plate-and-frame-filter-press zoom


merrill crowe zinc precipitate filter press (2) zoom


merrill-crowe_press_filter zoom


plate and frame filter press (1) zoom


merrill crowe zinc precipitate filter press (1) zoom


merrill crowe zinc precipitate filter press (2)
plate and frame filter press (1)
merrill crowe zinc precipitate filter press (1)
Full Screen

Plate and Frame Filter Press

A plate filter often used to filtrate the silver/gold/zinc precipitate generated in a Merrill Crowe process. These filters have the advantage of low cost, great strength and ease of internal inspection.

Plate and frame filters are made in every conceivable combination of inlet and outlet positions. Bottom inlet and top outlet positions are considered best for precoating and filter aid suspension. In larger sizes it is preferable that these are at opposite ends of the filter. All air should be purged from the filter before precoating is completed. This may be difficult if gasketed filter septa are used.canada manufacturer

  • Capacity/Sizes 0.6 cu.ft. to 6 cu.ft. 
  • Mild steel construction
  • Blanchard ground head and tail plate to ensure flatness
  • Articulating coupling at the tail plate to hydraulic cylinder rod connection
  • Centre feed with four corner discharge
  • Polypropylene recessed filter plates
  • Polypropylene gasketed filter clothes
  • Closure: 2-stage automatic air/oil hydraulic pump
  • Opening: automatic, spring-assisted
  • Hydraulic pump, pressure gauge and air blow-down header with valves


  • Sludge hopper
  • Elevated frame



Metal filter press of the plate and frame type having the passageways in the internal comers of the plates and frames, showing the filter cloths in position.Metal filter press of the plate and frame pattern
with passageways in external lugs. Joints in the lugs made by cloth cuffs or lipped rubber collars.

plate and frame filter press

There are two basic types of filters. One is the plate-and-frame, the other is the recessed-plate type. The plate-and-frame filter press consists of a skeleton framework made up to two end supports connected by two horizontal parallel bars. On the bars a varying number of filter chambers are assembled which consist of medium-covered plates alternating with frames which provide space for the cake. The chambers are closed and tightened by a screw or hydraulic ram, which forces the plates and frames together, making a gasket of the filter cloth. The charge enters the filter press under pressure and fills each chamber approximately simultaneously. The liquid passes through the filter medium, which in turn retains the solids. The clear filtrate is removed at a discharge outlet. The filter cake builds up until the frames are full – judging by filtering time, decrease in feed rate, or rise in back-pressure. Once the frames are full of cake, filtering is stopped and wash liquid applied if necessary; this may be followed by deliquoring the cake. There arc various ways of arranging feed inlet, filtrate outlet, and wash-liquor inlet port. For example, in simple washing the wash liquor follows the same path as filtrate, while in thorough washing the liquid is admitted to the faces of alternate plates and then passes through the entire cake thickness to drain away on the other plates.merrill-crowe_press_filter

The recessed-plate filter has no frame; each plate serves as both plate and frame. The feed slurry enters through a larger central port, and filter cake begins to form in the recess in each side of the plate. In order to minimize the strain on the filter cloth, the depth of the recess is usually about 16 mm. giving a maximum cake thickness of about 32 mm.

The advantages of a filter press are adaptability to high pressures, production of a dry washed cake, durability, easy alterability of media and frames, and flexibility. Disadvantages include high labor cost unless mechanized, leakage, and exposure of product to air during discharge. The provision of mechanized systems to move the filter plates and to open and close the filter press at the end and commencement of the filtration cycle can reduce operating manpower requirements. Filter press materials of construction include cast iron, wood, stainless steel, glass-filled polyester, polypropylene without fillers, and aluminum; metal plates and frames may have a rubber or phenolic coating, or they may be entirely of plastic.


merrill crowe zinc precipitate filter press (1)

plate_and_frame_filter_press plate_and_frame_filter_press_001



Utilities Specifications

Air Hookup (if so equipped)

Note: All values for one press only. If more than one press is used, air consumption must be carefully reviewed for total capacity.

Standard Plant Quality Air: Maximum particle size: 40u

Air Blow: 1.0 scfm per ft³ press capacity @ 40 psi (ANSI/ISA-57.3 – 1975, RI 981)

Instrument Quality Air: Maximum particle size: 3
Oil content less than 1 ppmm wet weight or v/u under normal operating conditions.
Pressure dew point at least 180 F below the lowest ambient temperature.
Air shall be free of all corrosive contaminants and hazardous substances.

Air Requirements For Press Closure: 12 scfm @ 100 PSI

The air processes listed with an asterisk do not occur simultaneously. The values listed are general estimates. Due to the highly variable nature of pressure filtration, accurate determination of total air requirements must be done on a case by case basis. For more detailed information contact ErtelAlsop.


Connected Power (if required): 15 amp @ 120VAC / I ph/ 60Hz

The customer is required to punch a hole in the electrical enclosure to supply incoming power to the panel.

Safety Instructions


To ensure maximum safety, optimum performance, and to gain knowledge of the product, it is essential that any operators of the filter press read and understand the contents of this manual before operating the press. Pay particular attention to the safety symbol, which means CAUTION, WARNING OR DANGER— “personal safety instruction”. Read and understand the instruction because your safety depends upon it. Failure to comply with the instruction can result in machine damage or personal injury.

The precautions mentioned in this manual are not intended to cover all of the hazards that can exist in a plant or with regard to this machine. Using safety mechanisms requires the constant attention of everyone near this (or any) machine.

A plant and related equipment are only as safe as the personnel using them. Proper equipment maintenance and use of personal safety devices will contribute much toward safety as will any number of mechanical devices.

Study this manual before attempting to install, operate or maintain this filter press.

Only competent, well-trained individuals should operate or maintain this equipment.

Explain the operation of this machine and its safety devices to a new operator before his or her operating the machine. Be certain the operator fully understands the machine, and is qualified to handle such operation.

Develop a safety checklist for the devices on this machine and perform regular maintenance to ensure proper operation.

As required by OSHA 1910.0151 ( C ), we also encourage the customers of its various products to install eyewash and/or safety showers adjacent to the product installation.





CAUTION: The main air supply to the machine should be free from water and oil. The presence of water or oil can cause severe damage to the hydraulic components. Air supply to the press should be a minimum of 85 psi and maximum of 100 psi. Disconnect the air supply before servicing the press. See the Air Quality Specifications in the Installation and Setup Section of this manual for detailed information.

CAUTION: Disconnect electrical power before servicing the press. See following section on proper lockout procedure.

CAUTION: Do not operate this machine unless all safety devices are in proper working order. Check all devices before starting the machine.

CAUTION: Do not stop the feed in mid-cycle! Stopping the feed in mid-cycle causes settling of the formed solids, which may plug the center feed eye. Restarting the cycle with a plugged feed eye will cause differential pressure across the plate web. This will lead to distortion of the web or total failure of the plates.

Recommended Lockout or Tag Out System Procedures

Lockout is the preferred method of isolating machines or equipment from energy sources. The following simple procedure is provided for use in either lockout or tag out programs. This procedure may be used when there are limited number or types of machines or equipment or there is a single power source. For more complex systems, a more comprehensive procedure will need to be developed, documented and utilized.

Lockout (or Tag Out) Procedure


This procedure establishes the minimum requirements for the lockout or tag out of energy isolating devices. It shall be used to ensure that the machine or equipment is isolated from all potentially hazardous energy and locked out or tagged out before employees perform any servicing or maintenance activities where the unexpected energizing, start-up or release of stored energy could cause injury.


Appropriate employees shall be instructed in the safety significance of the lockout (or tag out) procedure. Each new or transferred employee and other employees whose work operations may be in the area shall be instructed in the purpose and use of the lockout or tag out procedure.

Preparation for Lockout or Tag Out

Make a survey to locate and identify all isolating devices to be certain which switch(s), valve(s) or other energy isolating devices apply to the equipment to be locked or tagged out. More than one energy source (electrical, mechanical, or others) may be involved.

Sequence of Lockout or Tag Out System Procedure

  1. Notify all affected employees that a lockout or tag out system is going to be used. The authorized employee shall know the type and magnitude of energy that the machine or equipment utilizes and shall understand the hazards.
  2. If the machine or equipment is operating, shut it down by normal shutdown procedure.
  3. Operate the switch, valve or other energy isolating device(s) so that the equipment is isolated from its energy source(s). Stored energy, (such as that in springs, elevated machine members, rotating flywheels, hydraulic systems, and air, gas, steam, or water pressure, etc.) must be dissipated or restrained by methods such as repositioning, blocking or bleeding down.
  4. Lockout or tag out the energy isolating devices with assigned individual lock(s) or tag(s).
  5. After ensuring that no personnel are exposed, and as a check on having disconnected the energy sources, operate the push button or other normal operating controls to make certain the equipment will not operate. CAUTION: Return operating control(s) to “Neutral” or “Off” position after test.
  6. The equipment is now locked out or tagged out.

Restoring Machines or Equipment to Normal Production Operations

  1. After service and/or maintenance is complete, and equipment is ready for normal production operations, check the area around the machines/equipment to ensure that no one is exposed.
  2. After all tools have been removed from the machine/equipment, guards have been reinstalled and employees are in the clear, remove all lockout or tag out devices. Operated the energy isolating devices to restore energy to the machine/equipment.

Procedure Involving More Than One Person

In the preceding steps, if more than one individual is required to lockout or tag out equipment, each shall place his/her own personal lockout or tag out device on the energy isolating device(s). When an energy isolating device cannot accept multiple locks or tags, a multiple lockout or tag out device (hasp) may be used. If lockout is used, a single lock may be used to lockout the machine/equipment with the key being placed in a lockout box or cabinet. Each employee will then use his/her own lock to secure the box or cabinet.

Basic Rules for Using Lockout or Tag Out System Procedure

All equipment shall be locked out or tagged out to protect against accidental or inadvertent operation when such operation could cause injury to personnel. Do not attempt to operate any switch, valve, or other energy isolating device where it is locked or tagged out.


Chemical Resistance

Chemical resistance data are shown based on laboratory tests and compiled by the manufacturers of the resins. When using the table, please remember that many factors, such as concentration, temperature and the presence of impurities can change the rate of corrosion. For this reason, the chemical resistance charts should be used as a first approximation of your requirements rather than the final answer. All thermoplastic pipe should be tested under actual service conditions to determine its suitability for a specific purpose.

The Chemical Resistance Chart that follows is compliments of:

“A” = Excellent
“B” = Good, minor effect
“C” = Fair, needs further testing
“X” = Unsuitable


PVC – Polyvinyl Chloride
ABS – Acrylonitrile-Butadiene-Stryene
CPVC -Chlorinated Polyvinyl Chloride
PP – Polypropylene
PB – Polybutylene
LLDPE – Linear Low-Density Polyethylene
LDPE – Low-Density Polyethylene
HDPE – High-Density Polyethylene
CLDHPE – Cross-Linked High-Density Polyethylene
PVDF – Polyvinylidene Fluoride
PFA – Teflon


Model NumberEA-470-25.1.0-1.0-CG-M
Serial Number(s)EA470-6-0111
Maximum Inlet Feed Pump Pressure100 PSI (See Pressure/Temp Curves)
Total Volume1.73 ft³ (.0489 M3)
Number of Chambers:20 chambers
Total Filter Area:37.2 ft² (3.43 M²)
Plate Size:470 mm x 470 mm
Plate Style:Recessed Chamber
Plate Material:Polypropylene
Gasket Material:N/A
Filter Cloth:Polypropylene
Overall Press Length:66 21/32 Inches
Overall Press Width:22 3/4 Inches
Manifold ArrangementPVC Head Connections Only
Control LocationTop Cross Head
Control TypeSwitched Air Hydraulic
Closing DevicePneumatic Operated Hydraulic System
Hydraulic Clamping Pressure3200 psi
Relief Valve Setting3800 psi
Hydraulic Cylinder-Size4” diameter x 12” stroke
Hydraulic Oil RecommendedHO-68-7 or equivalent

Installation & Setup


Before beginning an installation, read and follow all of the instructions in this part of the manual. Pay close attention to the WARNING, NOTE and CAUTION statements to prevent personal injury and damage to the equipment.

Customer Service

This Installation and Start Up Section gives general guidelines for installation of the ErtelAlsop press. The customer is responsible for installation and must use his judgment and knowledge of his equipment, procedures and people to determine the best installation method. If there are any questions regarding interface, hookups, or installation, contact the Customer Service Department (see Section One) for further information. ErtelAlsop will not be liable for recommendations given by anyone other than ErtelAlsop.


Consult the temperature/pressure curves and chemical resistance chart in the safety section of this manual to insure safe and proper operation of the press.

Air Quality Specification

Use the following guidelines for air hookup to the filter press.

Air Blow, Core Blow use standard plant air:

Maximum particle size-40um

Air-Operated Diaphragm Pumps require “Pump Quality Air”

Maximum particle size-5um
Pressure dew point-at least 18°F below the lowest ambient temperature.
Lubricate with ISO Grade 15,5 Weight, Arctic Oil (unless lube free pump)
Air shall be free of all corrosive contaminants and hazardous substances.

Air over Oil Hydraulic System, Air-Operated Plate Shifter, Automatic Pump Control System

Require Instrument Quality Air (ANSI/ISA-57.3 – 1975, RI 981)

Maximum particle size -3um
Oil content to be less than 1 PPM wet weight or v/u under normal operating conditions.
Pressure dew point-at least 18°F below the lowest ambient temperature.
Air shall be free of all corrosive contaminants and hazardous substances.

Customer Interface

The following connections may be required. Review the list, then consult the Press Assembly Drawing in the Drawings Section of this manual for specific connections, locations and capacities required.

Feed Connections

  • Standard Slurry Feed
  • Double-End Slurry Feed
  • Precoat
  • Wash
  • Membrane Plate Squeeze

Discharge Connections

  • Filtrate
  • Launder
  • Core Blow


  • Press Closure
  • Air-Operated Plate Shifter
  • Air Blow
  • Core Blow
  • Cake Discharge


  • Filter Press
  • Electrical Panel
  • Drip Tray Doors
  • Pump Skid


  • Volts, Phase, Current

Press Installation

Receiving and Handling-Inspect all equipment immediately upon receipt. If any damage occurred during shipping, notify your Customer Service Manager (see Section One) and the carrier for Claims Inspection.

Recommended Moving Procedure

Carefully remove the ErtelAlsop press from the transport vehicle. Use Screw Eyes for lifting the press. There are threaded holes at each end. A spreader bar the length of the press or two lifting devices should be used so that the lifting cables lift vertically. Use qualified riggers and appropriate equipment when lifting and moving the press.

NOTE: If your ErtelAlsop press has a semi-automatic plate shifter, the strap must go between the rail and the sidebar. Placing the strap on the outside of the rail could lead to damage or failure of the rail!

CAUTION: Insure that the lifting device has sufficient capacity to lift the ErtelAlsop press.

DANGER: Do not stand under the press when lifting or moving.

Storing the ErtelAlsop Press

If the ErtelAlsop press is stored for any length of time before installation, store it in a temperature range of 40-90° F, out of direct sunlight.

The cylinder should be cycled at least once a month during extended storage periods to insure that the seals stay flexible.

Foundation Requirements

Prior to the installation of the ErtelAlsop press, a level and square foundation must be prepared. Reference the press drawing for mounting details.

CAUTION: Allow suitable time for the foundation to cure before installing the ErtelAlsop press.

Mounting and Leveling the ErtelAlsop Press

  1. Place the ErtelAlsop press on the foundation and level the press horizontally and vertically.
  2. Square the press by measuring diagonally across the corners of the press.
  3. Tighten the head leg bolts.
  4. Install the plates if they were shipped separately.
  5. Close the press to full operating pressure.
  6. Tighten the cylinder bracket leg bolts while the press is under full pressure. NOTE: It is recommended that the cylinder end of every ErtelAlsop press be allowed to “float” for expansion/contraction of the side bars. Consult ErtelAlsop if further assistance is needed on this procedure.

Process Connection to the ErtelAlsop Press

Make the necessary adjustments until the press is properly mounted (leveled, squared and lagged) before continuing with these instructions.

Connect the center inlet on the ErtelAlsop press manifold to the discharge outlet of the feed pump. The feed run line should be the same size as the inlet on the manifold. The feed line must not be supported by the press.

CAUTION: Use appropriate pressure and temperature rated pipe to connect the feed pump to the ErtelAlsop press feed pipe. Consult the temperature/pressure curves and chemical resistance chart in the safety section of this manual to insure safe and proper operation of the press.

Install the drain pipe to the bottom outlet of the ErtelAlsop press manifold as shown below.

CAUTION: The filtrate drains from the press by gravity. Therefore the outlet of the drain pipe must be below the level of the discharge manifold outlet.

NOTE: If this arrangement is not feasible, consult ErtelAlsop to determine alternative piping, valve and pump arrangements that must be made to insure correct operation of the ErtelAlsop press.


Cold Weather and High Temperature Operation

Standard or high pressure plates (polypropylene) cannot tolerate temperature gradients or operation at temperatures of 40°F or lower. The plates must be also be within 60°F of the temperature of the slurry, and operate within the temperature range indicated on the temperature/pressure curve found in the Safety section of this manual. Under these conditions, the plates must be preheated before sludge can be pumped into the press. The plates can be preheated with warm water or warm air to raise the temperature slowly to about 45-65°F for normal operation.

  1. The filter press must be piped to an external tank that can be heated, raising the temperature of the preheat filtrate slowly. Hot filtrate cannot be pumped directly, or the plates will encounter thermal shock.
  2. Pump the preheat filtrate through the press for 30 minutes or until the discharge filtrate is within 10°F of the feed filtrate. The valves should be set up the same way as for the precoat with a slow rate of flow through the press, this gives the preheat filtrate a chance to heat the plates slowly.
  3. Proceed with normal processing.

Cold Weather Shutdown

Following are the steps required for a cold weather shutdown (35°F or lower)

  1. Immediately after the last cycle, close the press and valves for a blowdown, and run air through the plates and cloths for 30 minutes. This removes most water from the cloths.
  2. Open the lower left valve to remove the filtrate from that side of the plates, blowing air for about 10 minutes to remove water from the discharge eyes.
  3. Pressurize the press by closing all valves, and opening the air blow valve, pressurizing the press with air pressure to about 40 psi. After the press is pressurized, open the feed pipe valve to blow out the sludge in the pipe between the pump and the press. Do the same for the precoat pump if applicable.
  4. Disconnect the inlet hose to the pump and insert a similar hose into a barrel of premixed antifreeze. Run the pump slowly with about 10 psi air pressure until some antifreeze comes out the end of the lower discharge eye. Do the same for the precoat pump if used.
  5. Blow out all hoses. Drain any water in the air compressor tank if supplied.

The goal is to remove all water in anything that can freeze and break.

Head Connections

Your ErtelAlsop filter press comes complete with head connections to provide proper feed line and outlet line sizes. They are intended to adapt directly to standard NPT pipe sizes for ease of assembly.

If your press is fitted with a center feed (this feed may be center or bottom center located), the appropriate head connections should screw through the head plate for approximately ½-inch. The corner or outlet head connections are screwed into the head plate until they bottom out.

Drape the head cloth over the head plate and the cloth pins at the top of the head plate to retain the cloth. Install the cloth nut by screwing it onto the ½-inch of feed connection piping protruding through the head plate, capturing the head cloth and retaining it against the surface of the head plate.

Install the lock nuts on each head connection and tighten them down against the outside face of the stationary head. DO NOT OVERTIGHTEN. The press is now ready to pipe fitted for feed and outlet lines.


If outlets are to be manifolded together, keep manifold area equal to or greater than the sum of the areas of the pipes entering it. Otherwise, back pressure may occur causing leakage and longer filtration cycles.

Discharge Pipes

The discharge pipes at the four corners of the head are used for draining clear filtrate from the plate stack. The discharge pipes are simply threaded into the head plate. To remove a discharge pipe, use a strap wrench to grasp the threads of the discharge pipe. A pipe wrench may be used, but this can damage the threads. If using a wrench, be sure to clamp on an area of the threads that is not used for engagement to other components.

Cloth Removal and Installation Non-Gasketed Plates (if applicable)

Cloth Removal

  1. Cut the ties on the vertical sides of the plates that hold the two cloth faces together outside the plate.
  2. Lift the cloth off the cloth dogs on the top of the plate.
  3. Pull the cloth through the center feed eye of the plate.

Cloth Installation

  1. Fold one side of the cloth and insert it through the center feed eye of the plate.
  2. Lift the cloth over the cloth dogs on top of the plate.
  3. Join the two edges on the sides of the filter plate with wire ties or similar clips.

See Step By Step Instructions For Installation of Filter Media Which Follow

Cloth Removal and Installation-Gasketed Plates (if applicable)

Cloth Removal

To remove a filter cloth from a gasketed plate, insert a thin bladed screwdriver into the groove at the outer edge of the caulking and pry out a small section of the cloth. Grasp the sash cord caulking with pliers and pull the remaining cloth out of the caulking groove. Do this on both sides of the plate. Pull the cloth through the center feed eye of the plate. After the cloth is removed, inspect and remove any accumulated solids from the groove before inserting the new

Cloth Installation

The tool for installing and retaining material (O-ring caulking and sash cords) is a simple wedge of polypropylene or some other no-shattering material. This can be purchased by contacting ErtelAlsop or your authorized representative directly.

CAUTION: Do not use a metal wedge since this may damage the cord or filter cloth.

Place the cloth against the plate and tap in a small section of the sash cord or O-ring on the top to hold the cloth in position. Line up and caulk the diagonal sections first to insure proper alignment of the cloth. Distribute the caulking on the sides, top and bottom by caulking in the center of these long sections first. Proceed to insert the balance of the caulking, insuring that the caulking is evenly distributed. Even though there may appear to be a surplus of material, this can be worked in easily.

Regasketing the Filter Plates (if applicable)

  1. Insert the gasket starting at the bottom center of the filter plate using a wood or plastic mallet. Push the gasket into the groove around the outer edge of the plate until it mates at the center of the plate. Many installers will incorrectly stretch the gasket material. This reduces the cross section, making it easier to insert. However, by stretching the gasket material for easier installation, it has a tendency to creep and open the buffed joint of the gasket, causing leakage.
  2. Cut the gasket approximately ½-inch to 1-inch longer than required, cutting the end squarely.
  3. Apply one or two drops of Eastman 910 (or equivalent “Super Glue”) to one end of the gasket and quickly join it to the other end. Hold it under hand pressure for approximately 30 seconds. Then crowd the excess gasket into the groove to insure fullness of gasket material.
  4. Install the discharge eye gaskets in the same manner.

Gasket life depends on many factors, such as length of filtration cycle, temperature, and excessive closing force. Gasket replacement should take place if the gasket appears to be delaminating or shredding into small pieces. Also, if excessive temperatures exist and cycles are very long, the EPDM elastomer (standard gasket material) may go into additional cure, causing it to harden slightly. If the gasket life of the EPDM elastomer is unsatisfactory, contact ErtelAlsop or your authorized representative for a suitable replacement.

Note: When gasketed plates are first put to use, the new gasket material may be slightly sticky or gummy and cause gaskets to pull out of the grooves when plates are separated. This condition is eliminated as product film builds up. If any gaskets demonstrate this condition, apply a silicone spray until the press has been used several times.

Membrane Plates (if applicable)

Membrane Plates have a separate operation manual.

Air/Oil Power Unit

The ErtelAlsop Automatic Hydraulic Oil Pressure Unit uses a regulated air supply (customer supplied) to produce a constant pressure oil output adjustable for proper closing force of any filter press. The unit contains two air/oil booster pumps. One provides a high volume output for rapid advance and retract, while the other provides high pressure for clamping force. A manual valve is provided for advance, neutral and retract positions. Two gauges are provided to monitor air input pressure and hydraulic clamping force.

Inlet Air:

No lubrication required
100 psi maximum pressure
80 psi minimum pressure

To Close:

Move the selector switch to the close position. When the press is fully closed the gauge will read proper hydraulic pressure and booster will stall. Feed pumps may now be started. LEAVE SWITCH IN THE CLOSE POSITION DURING FILTER CYCLE.

To Open:

Move the selector switch to the open position. When the press is fully open, move the switch to the neutral position. Press is now ready to be cleaned. CAUTION: Customer air shut-off is required when servicing this device. If air supply is left on, high pressure oil may be trapped between the booster and the check valve. During the filtration cycle, booster may periodically cycle. This is a normal condition, which maintains closing force.

Relief Valve Setting (optional)

The Relief Cartridge is a basic service item, which is easily removed from the body for cleaning or replacement, but is not designed to be disassembled or repaired in the field. It is never necessary to remove the entire valve from the circuit piping. Simply unscrew the cartridge from the body.

The most common cause of a cartridge failing to operate is dirt in the hydraulic system. If the cartridge does not operate as required, it should be removed from the valve body and thoroughly cleaned by washing in a suitable solvent. If the cleaning procedure does not eliminate the problem, replace the cartridge.

The pressure may be adjusted by screwing in the stem to increase pressure setting or out to decrease the pressure. The following procedure may be used to adjust the valve cartridge setting:

  1. Select the close position with valve actuator item 18.
  2. Gradually increase air pressure by adjusting regulator item 2 until relief valve setting is reached. The correct relief valve setting varies depending on the press and its application. The correct settings for working pressure and relief valve pressure may be found on the general arrangement drawing, which came with your press.
  3. Adjust the relief valve by turning stem in or out until pressure reaches correct setting and then drops back approximately 200 psi. Tighten the cartridge locking nut at this point.
  4. Select the open position with valve actuator item 18. Once pressure drops off return selector to close position and observe the highest pressure reading before the pressure drops off. This should equal the relief valve pressure setting.
  5. Reduce booster air pressure by adjusting the regulator item 2 until specified working pressure is achieved.

Automatic Pump Controller(optional)

Theory of Operation

The pump control unit uses a pressure transmitter to measure the pressure in the output line of an air operated pump. This transmitter generates a signal, which is proportional to the pressure applied. This signal is used to regulate an electrical proportional control valve, which provides a pneumatic signal proportional to the signal received the pressure transmitter. As the pressure in the output line of the pump increases, the pneumatic signal increases which, in turn, increases the output pressure of the pump.

Once the output line pressure of the pump reaches a pre-set value a timer is started which allows the pump to operate at a particular pressure for an adjustable amount of time. This pre-set pressure setting is achieved by the installation of a pressure switch in the output line of the pump. The purpose of this function is to allow the pump to pack more material into the press toward the end of the cycle, at a higher pressure, in order to more effectively dewater the cake.

The timer is provided with an accumulation device so that a drop below the preset pressure value does not reset the timer. This allows the timer to record the period of time the pump spends in the final pressure range and allows the cycle to end upon completion of the timed cycle.


It is the customer’s responsibility to install the components of this product in conformance with all local codes for electric and plumbing. This will include the mounting of the control box, installation of the pressure transmitter and pressure switch in the output line of the pump, plumbing the air supply to the proportional control valve and mounting tile proportional control valve to the air operated pump. All electrical interconnections will be performed at the control box terminal strip.

Identify the pressure transmitter and the isolation diaphragm. These components should already be assembled. Note that the isolation diaphragm has a pipe connection at the bottom to accept a pipe nipple. Thread the transmitter/diaphragm assembly into a nipple installed in the feed line between the pump and the filter press feed connection. DO NOT DISASSEMBLE THE DIAPHRAGM FROM THE PRESSURE TRANSMITTER AS IT HAS BEEN FACTORY FILLED WITH GLYCERIN AND SEALED.

The proportional control valve and regulator assembly should come as one assembly. The output side of the regulator should be piped to the air input connection on the air operated diaphragm pump. As the size of the connection will vary with the size of the pump, it may be necessary to bush the air input connection of the air operated diaphragm pump.

Connect the air supply to the inlet side of the proportional valve assembly. The inlet air pressure should be regulated not to exceed 100 psig. Exceeding 100 psig may cause damage to the sensor in the proportional control valve.

The air supply should have a valve for cut-off and servicing purposes and should be clean, dry and free of oil and other contaminants.

Please see electrical wiring diagram. Mount the control box at a location convenient to the air operated pump. Make certain that the cables attached to the control box will reach the pressure transmitter and proportional control valve. The pressure transmitter and proportional control valve connections are made with threaded connector permanently attached to the end of the appropriate cable. Push the connector firmly onto the pins protruding from the top of the transmitter and proportional control valve and screw down the locking nut. Make certain the pins line up wit the appropriate sockets in the connector.

Bring 120V/1PH/60HZ electrical to the control panel at the appropriate terminals as shown on the diagram. The components supplied with the Automatic Pump Controller are rated for NEMA 4 due to the nature of filtration applications. All wiring and interconnections must meet this standard. Please observe all local codes when installing the equipment.

Semi-Automatic Plate Shifter

The Semi-Automatic Plate Shifter uses an air motor to turn a sprocketed shaft, which supplies mechanical motion through a chain, to the shifter framework. A pair of cams are used to latch on an air cylinder, one on each side. For a complete pneumatic diagram, please see Drawing elsewhere in this manual.

To operate the shifter, begin by selecting “open” on the control console. When the press is completely open, the operator would depress the palm button on the shifter framework. The shifter will move toward the first plate to be shifted. Depress the palm button again and the framework will shift the first plate to the slide head. Continue depressing the palm button until all of the plates are shifted, cleaning out the cake as you move through the plate stack. When the last plate has shifted, depress the palm button once more to send the plate shifter framework to its home position, at the crosshead/cylinder end of the press. Once shifter is “home”, the cams will extend up and you are ready for another press cycle.

All adjustable conditions have been factory set; however it may be necessary to occasionally adjust cam extension pressure or air motor force. If the cams are lifting the plate as they pass under them, reduce the force applied by decreasing the regulator pressure opposite the palm button. If the plate shifter is applying excessive force to the plate handles, decrease the setting of the regulator inside the console. CAUTION: THERE ARE TWO REGULATORS INSIDE THE CONSOLE. MAKE SURE THE CORRECT ONE IS ADJUSTED.

If the shifter runs too fast or too slow, open or close the exhaust mufflers on the air motor valve in the control unit enclosure. Use caution when making these adjustments as a small change can create a large difference.

General Description

Press Frame (Sidebar)

The press frame incorporates four primary components: the Head, the Slide Head/Follower, the Fixed Cylinder End and the Sidebars.

The Head end of the press serves as the fixed loading surface for the plate stack. It supplies the opposing force necessary for holding the plate stack together during processing. The Head also serves as the interface between the feed inlet and discharge connections.

The Fixed Cylinder End is the mounting surface for the Hydraulic Cylinder.

The Sidebars connect the Head and the Cylinder End. They support and guide the plate stack, and maintain the plate stack position for proper sealing. The Sidebars also support the Slide Head/Follower.


The Follower is the moving portion of the filter press used to compress the plate stack for filtration cycles. The Follower uses a coupler arrangement to attach to the Hydraulic Cylinder. This serves two functions:

Cylinder (Optional on Air Oil Systems only)

The Cylinder moves the Follower open and closed and provides the clamping force necessary to seal the plate stack during the process cycle. A Boot around the Cylinder Rod provides protection from dirt and process.

Hydraulic Power Unit(optional)

The Hydraulic System provides the hydraulic fluid flow to the Hydraulic Cylinder. The pump converts instrument quality air to hydraulic pressure through a ratio system that uses a large area air piston at low pressure to produce a high hydraulic pressure on a small area hydraulic piston. As the hydraulic output approaches the desired preset pressure, the pump slows down and stalls when the hydraulic force is then maintained with no additional power supplied.

This system provides self-compensating pressure for stack contraction or expansion. Stack contraction occurs, the hydraulic thrust reduces, causing an imbalance in the pump. The pump then cycles to restore the hydraulic thrust to the desired setting.

During many applications involving polypropylene filter elements, especially when filtration temperatures are high and wash temperatures low, filter stack expansion can create excessive pressures if the system is non-compensating.

This can create increased stresses on the press. (Under such circumstances, excessive leaking, frame bowing, and even structural failure of the press may result due to excessive clamping force between the plates.) When expansion occurs, the excess hydraulic pressure that results bleeds back to the hydraulic reservoir through a relief valve, maintaining the desired hydraulic thrust.

A pressure difference between clamping force and relief pressure is provided for process startup. At the beginning of a process cycle a temporary peak is seen in the hydraulic pressure. This is caused by the initial slurry flow into the press. If the relief pressure is set too closely to the clamping pressure, the relief will dump hydraulic fluid back into the reservoir. This will cause leaking since the Follower has moved slightly and allowed movement of the plates. It is therefore necessary to maintain a 400 psi difference between the clamping force and the relief setting.

Recessed Chamber Plates (Gasketed)

The recessed chamber plate has the following features: plate recess, feed eye, filtrate discharge eyes, filtrate ports, drainage surface and stay bosses.

Each plate recess is one half of a single chamber. Two plates pressed together create the whole chamber. The slurry passes through the feed eye, to the chambers where the solid portion of the slurry is deposited.

The drainage surface is at the most recessed point of the chamber and is made up of “pips” or “ribs.” The pips support the cloth and allow the filtrate to drain to the ports.

The filtrate ports discharge the filtrate (the liquid part of the substance being filtered) to the discharge eyes. The filtrate ports are at the four corners of the plate.

The stay bosses are approximately the total thickness of the plate. The function of the stay bosses is to stabilize the web (drainage surface) of the plate.

The plates have identification marks on the non operator side to aid the operator in placing or replacing plates in the press. Each plate is designed as either a one-button or three-button plate. A one-button, or non-wash plate, means that the small air/wash water ports are located near the lower and upper right corners of the plate. A three-button, or wash plate, has the small ports located near the lower and upper left corners. The alternating plate provides the porting necessary to begin the wash and air blowdown processes.

The order of the plates must follow a 1,3,1,3,1,3 sequence, beginning at the Head End of the press, to assure proper air blowdown and wash cycles. Gasketed plates allow less leakage than non-gasketed plates due to an O-ring seal around the chamber and filtration ports. The identification marks are visible on the side edge of the plates as shallow drill marks.

The cloth is retained in a machined groove located around the outer edge of the plate recess. The sewn-in sash cord filter cloths are made by sewing a high-density polypropylene sash cord around the outer edge of the cloth. Cord diameter depends on type of cloth and relative thickness being used. In most cases, a No. 12 (3/8-inch diameter) cord is used.

Blanking Plate

A Blanking Plate (Backup or Dummy Plate) can be inserted in the plate stack to isolate filter plates between the Backup Plate and the Follower. The Backup Plate allows a smaller batch to be processed since a smaller number of chambers are used in the process.

The Tail Plate MUST be relocated and inserted in front of the Backup Plate to form a complete chamber. Together the two plates provide the strength needed for safe press operation.

For correct press operation, proper plate sequencing 1,3,1,3 must be followed when relocating the Tail Plate and Blanking Plate.

Filter Cloths

ErtelAlsop has supplied filter cloth based on criteria supplied by the customer or based on sample processing either in the ErtelAlsop laboratory or at the customer’s facility. Should the process change, ErtelAlsop recommends that the cloth type be reevaluated for suitability. Information follows to help you better understand filter cloth and how it works. Detailed questions should be directed to ErtelAlsop.

Cloths for non-gasketed plates are hung over the plate, extending from top to bottom, and are held in place by eyelets, which fit over the cloth-pins on top of the plates. With the non-gasketed plate, the filter cloth provides the seal between the plates. Leakage will occur during operation even though ErtelAlsop normally supplies the non-gasketed plate cloths with latex edging. The latex will cut down the wicking action somewhat, but will not eliminate it. The gasketed plate allows less leakage than the non-gasketed plate due to an O-ring seal around the chamber and filtration ports. The gasketed cloth has a high-density sash cord sewn around the perimeter of the cloth, which is caulked into a groove on the plate.

The type of cloth used is determined by the type of process or application performed by the ErtelAlsop press, the operating environment, and the performance required by the filtration media (filter cloths).

The filter cloths come in many different materials including polypropylene, polyester, cotton and other synthetic materials. The cloths are made from either monofilament fibers, multifilament fibers, or spun fibers. The smooth surface characteristic of monofilament fibers can help to improve cake release properties. The uniform circumference of monofilaments also enable fabrics to be produced with consistent pore sizes. Multifilament and spun fibers are produced by twisting several smaller diameter monofilament fibers together to form a single strand. They are used to produce fabrics that require a very tight weave and fabrics where high flow rates are not critical. Filter cloths also come in many different styles of fabric weave.

Mesh opening or pore size is also an important consideration when selecting the proper filter cloth for a particular application. The mesh opening or pore size is determined by the number of fibers, size of the fiber, and the type of weave. These factors in turn govern flow rates, particle retention, and the strength of the fabric itself.

Cloth can be finished in several ways: heat set, scoured, calendared, single-glazed and double-glazed.

Process Manifold

The Process Manifold Assembly consists of all the plumbing, process valves, and control valves necessary for process flow into and out of the filter press. The safe state is normally open for discharge valves and normally closed for feed valves.

Cake Chute

The Chute directs discharged cake from under the press to a single location for easy handling.


Note: The manifold supplied includes precoat capabilities. Your particular process may or may not require a precoat.

Precoat and body feed are two related applications. Both of these special applications use diatomaceous earth (commonly known as DE), cellulose, perlite or fly ash as a filter aid when the solids in the slurry are extremely fine and free-filtering. The filter aid helps trap the fine solids that otherwise might flow through the filter cloths. The processes of precoat and body feed increase the clarity of the filtrate, provide for higher flow rates, more consistent runs, shorter cycles, dryer cakes, better cake release, and protect and increase the life of the cloths.

Precoat requires the following setup:

  • Dosage rate of 0.1 lb./ft² filtration area
  • Precoat feed rate of 0.25 to 0.5 gal/min/ft² filtration area
  • Precoat tank size-approximately 1.5 times the holding capacity of the ErtelAlsop press.
  • Filtrate discharge capable of returning to the precoat tank for continuous flow.
  • Press discharge manifold should be “uniform-fill” type.

Uniform-fill is a filtration function used with rapidly settling solids. With rapid settling, an uneven solids distribution occurs with larger particles settling into the lower portion of the chamber before even pressure can be built up. In this case it is necessary to fill the press from bottom to top and end to end, allowing uniform distribution of the solids. If this is not done, a pressure differential can be built across the plate, and possible plate breakage can occur.

Note: The manifold supplied includes uniform-fill capabilities. Your particular process may or may not require uniform-fill.

Filtration Cycle (General Information)

General Rules of Filtration

  • Build pressure slowly. Building pressure too fast leads to cloth or cake binding.
  • Scrape plates between cycles if cake does not completely fall out.
  • Insure sufficient quantity of slurry to complete cycle. Use backup plate if sufficient quantity is not available.

Optional Automatic Pump Control (NEMA 4)

The ErtelAlsop Automatic Pump Controller regulates flow of slurry into the filter press AUTOMATICALLY.

The APC has three (3) components:

  1. The Air Pressure Control Valve: Receives a 4-20ma signal and controls the air pressure to the pump.
  2. Control Display Panel: 120 VAC control panel that is system controller-has LED pressure read-out to panel cover.
  3. Pressure Transmitter with Ceramic Base: Sends a 4-20ma signal based on inlet pressure of the filter press.

The system operates by measuring the pressure on the inlet side of the filter press (Pressure Transmitter #3). It then sends a signal to the air pressure control valve (#1), which increases the air pressure to the pump.

Air Oil Systems

Operation of Air Oil Systems

Closing Procedure (Single Switch Air/Hydraulic System)

If the air supply is properly connected to the press, the line pressure will register on the “Line Air Pressure Gauge”. Refer to the Specifications section for the required air pressure.

  1. Turn the “selector” switch to the “close” position. The hydraulic cylinder will extend and move the Follower and plate stack toward the Head End of the press. As the Follower meets resistance against the plate stack, hydraulic pressure will begin building. The hydraulic pump cycling rate will slow as it reaches the preset clamp pressure and will stall at operating pressure.
    CAUTION: Do not start pumping slurry until the press has closed and reached clamp

CAUTION: The air supply must be left “on” at all times, and the selector handle left in the “close” position during the complete process cycle. If the handle is turned to the “stop” position, clamp pressure will be lost and leaking or squirting may occur.


  1. Open the upper filtrate discharge valves. Close the lower filtrate discharge valves. This insures even flow across filter cloths.
  2. Start the precoat feed pump.
  3. After the filtrate runs clear, start the slurry feed pump or switch over valves on slurry lines. Velocity of slurry must be equal to or greater than the velocity of the precoat to prevent a pressure drop.
  4. Turn off the precoat pump.

Do not interrupt flow to the press at any time during the precoat or feed cycle. This will cause the precoat to fall off the filter cloths and collect at the bottom of the chambers. Poor filtration, uneven cake dryness and/or differential pressure on the plate stack may occur, resulting in plate failure.



  1. Close the lower filtrate discharge valves. Open the upper filtrate discharge valves.
  2. Begin slurry feed.
  3. When filtrate discharge begins flowing out of the press, open the lower filtrate discharge valves.

Filtration Cycle

Running the Filtration Cycle

  1. Open the feed valve and all filtrate discharge valves.
  2. Start the feed pump.
  3. Run the feed pump until maximum feed pressure has been reached and the pump has stalled.
  4. Turn off the feed pump (if manually controlled) and close the feed valve.

The cycle is now complete and the opening procedure can be performed (unless additional cake processing is performed such as air blow or core blow).

CAUTION: Do not stop the feed in mid-cycle! Stopping the feed in mid-cycle causes settling of the formed solids, which may plug the center feed eye. Restarting the cycle with a plugged feed eye will cause differential pressure across the plate web. This will lead to distortion of the web or total failure of the plates.

Automatic Pump Control


  1. Make certain the filter press is closed and up to pressure.
  2. Open appropriate valve for feed or discharge piping to and from the filter press.
  3. Open air supply valve to the pump.
  4. Select “start” from the selector switch on the face of the control box.
  5. When cycle is complete, the pump will stall out and cease operating.
  6. Press may now be opened and the cake discharged.

Air Blow

CAUTION: Air pressure must be regulated to 40 psi maximum. Failure to do so may cause adverse affects or failure of equipment.

  1. Shut off slurry pump.
  2. For manifolds with three discharge valves, close all filtrate discharge valves. For manifolds with four discharge valves, open the lower right filtrate discharge valve and close all other filtrate discharge valves.
    WARNING: It is extremely important to insure that the valves are set properly. Failure to do so may lead to equipment failure and personal injury!
  3. Close the feed valve(s).
  4. Open the air valve. Run air through the press for 2-3 minutes. If this does not remove all the water, longer filtration times should be performed.
  5. Open the filtrate discharge valves. Gravity will drain the press. Allow several minutes for complete drainage. The press can now be opened (or perform core blow if applicable).

Opening Procedure (Single Switch Air/Hydraulic System)

CAUTION: Make sure the feed pump has been turned off, and the pressure has been bled down!

  1. Turn the selector switch to the “open” position. Hydraulic pressure will bleed down then the Follower will open.
  2. After the press is opened, the plates can be shifted and the press emptied.

Preventative Maintenance

General Maintenance

An effective maintenance program is ultimately the responsibility of the customer. If properly maintained, the ErtelAlsop press will provide long and trouble-free service. You may use the following suggestions in establishing your comprehensive maintenance program:

  • Read and become familiar with this general maintenance information and the troubleshooting information.
  • Create a maintenance program and follow it diligently.
  • Use common sense precautions to prevent damage to the press or any part of the press.

The information and tables that follow should be a starting point for a maintenance program. Different slurries and factory conditions will affect press components differently. More or less frequent maintenance may be required.

Plate and Cloth Maintenance

CAUTION: KEEP CLOTHS CLEAN. Use a plastic spatula to scrape cake off the surface. Cake buildup can cause bending of the press frame. Excessive bending can lead to equipment failure! Keep the cloths and plates as clean as possible, especially along the sealing surfaces. Keep the following in mind when scraping cloths:

  • Use care not to cut or rip the cloth.
  • Cloths deteriorate over time and become more fragile and susceptible to tearing.
  • Make sure the edge of the spatula is smooth.
  • Do not tap the spatula on hard objects to remove cake from the spatula surface. This may form dents or tears in the spatula surface that can tear cloths.

The filter cloth is the initial barrier that separates the solids from the liquid, therefore, the filter cloth must remain porous to provide high filtration rates. During normal operation the filter cloth may gradually become plugged with small particles. The particles enter the cloth and become lodged in the depth of the weave, leading to decreased filtering action. Indications of plugged cloth include:

  • Initial high filtration pressure
  • Long filtration cycles
  • Wet filter cakes

Lodged particles must be removed periodically to maintain high filtration rates and dry cakes. A high-pressure, cold water spray unit with a capacity of 800-1200 psi and 2-10 gpm should have sufficient capacity. A broad spray nozzle should be used at a safe distance. If the pattern is too intense at a close distance, the cloth weave may be forced apart, leaving openings that allow sludge.

If high pressure washing does not improve performance, carefully pull back a corner of the filter cloth and check the drainage area and discharge ports of the plate for solids buildup. If there is any buildup, the cloths must be removed and the plates and cloth backs cleaned. Excessive buildup causes slow filtration cycles and can lead to plate breakage.

If there is no buildup behind the cloths, slight changes in the process may have changed the dewatering characteristics. Check all process parameters and insure that there have been no changes to the slurry characteristics.

If none of the above provides a solution, a more thorough cleaning process will be required to dissolve the entrapped particulate.

Cloth Washing

A re-circulation cleaning method using a particulate dissolving solution is the most effective cloth cleaning method. This method circulates an acid, caustic, or cleaning solution through the press to dissolve built up particulate. The type of solution depends on the slurry. Contact ErtelAlsop if you need assistance determining the appropriate solution.


Eye protection and protective clothing is required. Should you get acid or caustic in your eyes or on your skin, rinse with water immediately and seek medical attention, if necessary. Notify your supervisor of the incident.

CAUTION: Do not acid or caustic-wash non-gasketed filter plates unless extra precautions are taken to control leakage between plates.

CAUTION: Consult the chemical resistance chart in the Safety section of this manual to insure safe and proper operation of the press.

Setup & Requirements

  • Storage tank of sufficient capacity to fill the press and allow for re-circulation approximately 1.5 times the holding capacity of the press.
  • A low pressure (20-30 psi) pump.
  • Necessary plumbing (hoses or rigid PVC pipe) to isolate the press from the sludge stream and allow for both re-circulation to the storage tank and final draining of the spent solution. A throttling valve installed in the return line to the tank may be necessary to insure complete top and bottom press filling and wishing of the cloths.


  1. Clean filter cloths of all external material with a nylon or plastic spatula.
  2. Close the press.
  3. Disconnect the center feed line from the sludge pump.
  4. Connect the outlet of the acid pump to the center feed line of the press.
  5. Connect the filtrate discharge outlet of the press to the re-circulation tank.
  6. Open the feed line to the press.
  7. Start the feed pump. It may take considerable time to fill all the chambers of the press before the solution returns to the storage tank. Continually inspect the press for leakage during filling and circulation.
  8. Allow the solution to circulate for one to two hours.
  9. Turn off the feed pump.
  10. Perform and air blowdown to purge any remaining solution from the press.
  11. Disconnect the wash system and reinstall the sludge pump and outlet lines.
  12. Normal filtration cycles may be now be performed.

The plates can also be “dip washed” by immersing them in a tank of solution. The immersion method is less efficient than thorough-washing the press and will require a longer soak time. The plates will also float and require some method to keep them submerged.

Hydraulic Power Unit Maintenance

The Hydraulic Power Unit that came with your press has been filled with the correct grade of hydraulic oil and properly set for the correct closing force and relief conditions. As a general rule, no adjustments should be required.

It will be necessary to change the oil and the filter, where provided, on a regular basis. Interval lengths must be determined by application and working environment, however, the following information may be of use when setting up a program:

Always use clean oil and new filters. Never return used oil to the reservoir or reuse a filter. Do not use oil straight from the barrel, always filter it prior to filling the Hydraulic System reservoir.

  • Use clean containers, hoses and funnels when transferring oil.
  • Keep containers of oil tightly sealed.
  • Inspect filter elements for signs of failure, which may indicate a need to decrease time between service intervals.
  • Intake and return lines should be submerged in oil. If not, oil level in reservoir is too low.
  • Listen for unusual noises and change in performance. These are indicators of low oil levels, loose suction or return lines, clogged filter elements or air entrapment.

There are a limited number of tests that the average user can conduct. One simple test is to compare the same grade of clean oil with a sample from the power unit. The power unit sample should be allowed to sit overnight to promote settling of any contaminants. No foam should remain. A severe color change or a change in consistency means change the oil more often! It will always be cheaper to change the oil than to replace components.

Avoid the use of phosphate ester base, chlorinated hydrocarbon, water glycol and water based emulsion oils. This manual contains recommended specifications for hydraulic oil. ErtelAlsop cannot make recommendations as to specific manufacturers of hydraulic oil. A list of “or equal” oils is contained in the Section Three of this manual.

Under normal operating conditions, oil and filter, where provided, should be changed after 60 days and every 6 months thereafter.

press-filter preventive maintenance




Note: This troubleshooting guide gives general mechanical diagnostic guidelines. Use the following general guidelines for diagnosing electrical problems.

For Discrete Electrical Devices:

  1. Check that the main power is on.
  2. Check that all “Emergency Stop” buttons are reset.
  3. Check fuse or circuit breaker.
    If fuse is okay, proceed to Step 4
  4. Insure remote device has proper electrical signal
    Check remote device input voltage
    If voltage is acceptable, device is at fault and needs repair or replacement
    If voltage is not acceptable, continue to Step 5
  5. Inspect signaling device in main control panel
    Check signaling device output voltage
    If signaling device is sending proper signal, system wiring is at fault
    If signaling device is not giving proper signal, signaling device is at fault

For Analog Electrical Devices:

Pressure sensors and current to pressure (I/P) transducers require a thorough understanding of their operation for proper diagnostics. If you are not familiar with these devices, please consult the device manufacturer.

WARNING: Alteration of wiring or electrical devices is prohibited without the express written consent of ErtelAlsop. Unauthorized changes to the controls may result in:

  • Poor process performance
  • Severe damage to the equipment
  • Personal injury

Any change to the wiring and/or electrical controls on your press without written permission from ErtelAlsop voids any warranty.

Press Operations

Refer to the Hydraulic Schematic and parts location diagrams elsewhere in this manual.

  1. Press fails to close.
    A. Check gauge, if no reading, turn on air supply.
    B. Check selector switch position. Make sure it is in “close” position.
    C. Check oil level in the reservoir.
  2. Press fails to reach closing pressure.
    A. Check hydraulic pressure gauge. If booster is cycling and gauge shows fluctuation, increase the setting of relief valve.
    B. If previous step has no appreciable effort, lower the setting of regulator. If booster continues to cycle, the problem lies in the booster check valves of the main cylinder seals. Try bleeding system of any trapped air.
  3. Press fails to open.
    A. Check gauge. If no reading, turn on air supply.
    B. Check selector switch position. Make sure it is in “open” position.
    C. If above does not resolve the problem cylinder seals may be leaking.

press-filter recessed chamber plates



Automatic Pump Controller (NEMA 4)

  1. Pump will not start:
    A. Check incoming voltage.
    B. Check air supply
    C. Select “stop” on selector switch and then “start”
  2. Cake is damp or not sufficiently dewatered.
    A. Increase the amount of time on timer in control box.
    B. Check pressure switch setting. Is setting at maximum filtration pressure or lower? If lower, reset maximum.
    C. Check for cloth blinding. This occurs when solids penetrate the pores of the cloth and prevent or slow the filtration process. If this occurs, contact the factory for advice on filter media and/or precoating.
  3. Pump does not shut off.
    A. Pressure is set too high. Reduce setting to maximum filtration pressure.
    B. Check timer setting. Timer may be set for an excessive amount of time and not timing out at end of cycle.
  4. Pump develops pressure but it does not increase over time.
    A. Material being filtered may be free flowing and passing through the cloth. Check for clarity of filtrate. If cloudy, consult the factory for advice on filtering this type of material.
    B. Check regulated air supply to pump. If pressure is too low, increase amount of air pressure.
    C. If air pressure is inadequate, check voltage. Voltage should be between 1.5 to 10 volts depending upon pressure applied. If voltage is low pressure transmitter may be damaged.

Adjustments may be made to pressure transmitter and proportional valve however, these adjustments must only be made by persons familiar with this type of process instrumentation. Please consult the factory for additional information.

Cylinder (with Boot)

Cylinder BootWeeklyInspect boot for tears or holes. Repair/replace if damaged. Note: It is important that the boot maintain a seal around the cylinder rod since

certain processes may cause quick deterioration of the cylinder rod. Repair or replacement of the cylinder would be quite expensive, both in time and cost.


Hydraulic Power Unit

Clamp PressureDailyCheck for correct clamp pressure
Oil LevelMonthlyCheck for proper level

·         Fully retract Follower

·         Loosen pressure tube at top of reservoir

·         Remove plug from “Level Inspection Elbow” on side of reservoir

·         If level is low, no oil will be seen in elbow

·         Add oil, (filtered to 10 microns or less) at elbow or inspection tube until oil level reaches elbow.

·         Reconnect pressure hose to top of reservoir

·         Re-install plug in inspection elbow

Exhaust Filter/ReclassifierMonthlyDiscard exhaust oil from filter cup
Integrated Relief ValveQuarterlyCheck for proper setting
Hydraulic Oil & FilterYearlyReplace oil using type specified in Specification section of this manual (filtered to 10 microns or lower)

·         Fully retract Follower and remove plug from “Level Inspection Elbow” on side of Reservoir

·         Remove suction hose at manifold block (this hose connects to bottom of reservoir)

·         Lower suction hose into drain container

·         Reconnect suction hose and loosen air pressure

·         Add new filtered oil at elbow or inspection tube until oil reaches elbow

·         Reconnect pressure hose to reservoir top

·         Re-install plug in inspection elbow.


TroubleProbable CauseCorrective Action
Cloudy filtrateInsufficient quantity of precoat added to press.Need dosage rate of 0.1lb/ft² (1225 grams/m² filtration area)
Uneven distribution of precoat (if applicable)1.       Flow rate too low.

2.       Stopped precoat pump before starting feed pump (precoat falls to bottom of chamber).

3.       No precoat manifold.

1.       Need 0.25 to 0.5 gal/min/ft² (31-61 liters/m² filtration area)

2.       Start feed pump before stopping precoat pump.

3.       Contact ErtelAlsop or your authorized representative.


General Issues

TroubleProbable CauseCorrective Action
Pressing start button does not start the cycle (if Applicable)1.       Insufficient air supply to system

2.       Press not properly aligned.

1.       Ensure 100 psi system air pressure.

2.       Follow press closing procedure.

Pump stops mid-cycle.1.       Air supply pressure dropped and clamping force lost.

2.       Press closure switch in wrong position.

1.       Ensure 100 psi system air pressure.

2.       Ensure press is properly closed and clamped.

Recessed Chamber Plates (Gasketed)

TroubleProbable CauseCorrective Action
Plate breakage1.       Clogged Feed Ports.

2.       Irregular pumping of feed pumps.

3.       Short batches with insufficient solids.

4.       Solids built up in plate

drainage areas, reducing flow

to outlet. Plugged or partially

plugged outlet.

5.       High velocity constant

pressure/flow pumps such as progressive cavity pumps used for feeding sludge to the press may cause breakage due to velocity shock on one side of the plate.

6.       Improper use of backup plate.

7.       Pressure loading of plates-feed valve is closed when the feed pump is started, or outlet valves are closed when the feed pump is started.

8.       Careless handling of plates.

1A. Remove excess slurry remaining in feed eyes using a nylon cleaning spatula.

1B. Do not stop feed in mid-cycle.

2. Check pump to insure adequate pumping capacity and discharge pressure. Restart pump at a very low

pressure and gradually build pressure.

3. Have enough slurry available to complete the filter cycle, or obtain a backup plate to shorten the cycle.

4. Inspect plate drainage areas behind cloths frequently. Some cloths may allow more solids to pass through than

other style cloths. Unplug and clean outlet.

5. Use pumps with a pressure/flow curve

corresponding to the filtration curve of the material being filtered.

6. Place backup plate directly behind tail plate. Do not use tail plate alone to shorten chamber size.

7. Open all valves before starting feed pumps.

8. Handle plates carefully. Do not drop on side bars during installation or cleaning.

Water leaks out between plates1. Gaskets loose or torn.

2. Low hydraulic pressure

3. Wrinkle or hole in filter cloth.

4. Filter cake present in sealing surface.

1. Reinstall or replace.

2. Increase to required pressure.

3. Replace filter cloth.

4. Use nylon cleaning spatula to remove cake from sealing surface.

Filter cloths pull out of grooves during operationA full cake was not developed before wash or blowdown, causing cloth to be pushed out of caulking groove.Be sure chambers are completely full before wash or blowdown. The filter cake will then support the cloth.
Filter cloths pull out of grooves during operation, even though full cakes are being built.Improper size sash cord for cloth or application.Future cloths should be made with a slightly larger sash cord.

Filtration Cycle

TroubleProbable CauseCorrective Action
Solids in Filtrate1.       Holes in filter cloth.

2.       Filter cloth in head plate may be improperly installed.

3.       Filter cloth sash cord out of groove in gasketed plates.

4.       Incorrect filter cloth for application.

5.       Change in feed characteristics.

1. Replace filter cloths. Be careful when scraping cake-sharp edges may tear cloth.

2. Replace.

3. Clean groove and drainage

surface behind cloth and


4.&5. Submit sample for testing.

No filter cake formed (very little flow)1.       Material not amenable to pressure filtration.

2.       Filter cloths too blinded from polymer, oils, fine particulate, too high initial flow.

3.       Feed pump, feed line, or suction line plugged.

1.       Submit sample for testing.

2.       Clean or replace filter cloths.

3.       Clean as needed.

Partial filter cake formed (firm edges with liquid center)1.       Material not amenable to pressure filtration.

2.       Too low air pressure to feed pump (if air driven).

3.       Pump located below or too far away from filter press.

4.       Filter cloths partially blinded from polymers, oils, fine particulates.

5.       Ran out of feed material.

6.       Premature termination of cycle.

7.       Bodyfeed dosage too low, or inadequate pretreatment.

1.       Consult ErtelAlsop.

2.       Increase air pressure to maximum rating of filter press (last stage).

3.       Relocate pump next to filter press.

4.       Clean or replace filter cloths.

5.       Wait until more feed material is available or obtain backup plate.

6.       Allow longer time period between pump strokes at high pressure.

7.       Increase bodyfeed dosage or reevaluate treatment.

Uneven filter cake formation1.       Clogged feed eye.

2.       Plugged drainage surface or drain ports.

3.       Filter cloths partially blinded.

4.       Flow rate too low.

5.       Stopped feed pump during cycle and then restarted (filter cake slumps blocking feed eye)

1.       Clean at end of every cycle.

2.       Remove cloth and clean.

3.       Clean or replace filter cloths.

4.       Increase air pressure or pump size.

5.       Restart pump at low pressure and gradually build pressure.

Cycle time too long1.       Too low of solids in feed slurry.

2.       Dewatering characteristics of feed material.

3.       Filter cloths partially blinded.

4.       Feed pump undersized—too low of flow rate.

5.       Too low or air pressure to feed pump (if air drive)

6.       Filter press oversized.

1.       Concentrate/thicken solids in feed material.

2.       Add filter aid or evaluate treatment alternatives.

3.       Clean or replace filter cloths.

4.       Replace with larger pump.

5.       Increase air pressure to maximum rating of filter press.

6.       Wait until more feed material available before running.


I Need Assistance