Adjustable Stroke Diaphragm Pump

Simplicity and ease of discharge regulation — while in operation—is one of the many distinctive features of the Adjustable Stroke Diaphragm Pump. This is accomplished by means of a conveniently located handwheel which operates a heavy rod, moving the pivot end of the connecting rod closer to the fulcrum point of the walking beam, or farther away, to increase or decrease the stroke. Maximum diaphragm life is assured by the vertical motion of the rod operating the diaphragm, resulting in the elimination of excessive flexing and wear. Also, the diaphragm is always wet on both sides; preventing drying and resultant cracking. Valves are rubber faced and valve seats are rubber covered. The discharge bowl may be set at any one of four quadrants. Single or double discharge bowls are available as desired. All valve parts can be replaced without dismantling the pump.

Pump, Diaphragm

Adjustable Stroke Diaphragm Pump is designed for convenient mounting on thickeners and hydroclassifiers, and when mounted on a Thickener may be driven from the thickener mechanism. Arrangement of mounting is such as to place all parts so that an abrasive material cannot attack wearing surfaces. This insures longest possible life of wearing parts.

The Adjustable Stroke Diaphragm Pump is available in 2″, 3″, and 4″ sizes and in simplex, duplex, triplex and quadruplex types to give a wide range of capacities for the pumping of dense pulps, dewatered concentrates, tailings, cyanide pulps, and all sludges and slurries. As a filtrate pump, it ensures positive, trouble-free removal of solution from filtrate receivers at lowest cost per unit of capacity in filtering operations.

Cast steel, cast iron, and structural steel members make up the rugged mechanism and rigid framework, while bronze bearings are used at the critical points.

Adjustable Stroke Diaphragm Pump CapacityDimensionsDimensions

Adjustable Stroke Diaphragm Pump Stroke 5 ” and 6″

Pump, Diaphragm,

The 5″ and 6″ Adjustable Stroke Diaphragm Pump has the same distinctive features as the 2″, 3″ and 4″ sizes, plus exceptionally high capacity. One 6″ Adjustable Stroke Diaphragm Pump has a capacity equal to that of four 4″ pumps. Pump capacity can be varied one hundred percent while the pump is running by means of a conveniently located handwheel. Mechanical advantages are: (1) Valve can be removed without stopping the pump: (2) Bowl can be set to discharge in any of four quad-rants: (3) Vertical diaphragm motion prolongs life of diaphragm: (4) Bronze bushed hinge points and heavy main bearings: (5) Drive through cut tooth gears to the eccentric shaft: (6) Frame of heavy welded steel construction: (7) Alemite fittings for pressure lubrication insure minimum repair and operating costs.

Pump is available in 5″ and 6″ sizes and in simplex, duplex, triplex, and quadruplex types to give capacities ranging from 400 to over 3,000 tons of solids per 24 hours.

Adjustable Stroke Diaphragm Pump Capacity


Lowhead Diaphragm Pump

Pump, Diaphragm, Lowhead

Lowhead Diaphragm Pump is an inexpensive, reliable unit for pumping thick pulps, concentrates, sludges, and slurries; it is ideal for pumping thickener underflow.

The lowhead design requires a minimum of head¬room and construction is so that replacement of diaphragm and inspection of parts is simple. The entire upper casting, as shown in the illustration, hinges backward, bringing the diaphragm and rubber faced valves into easy accessibility. The pumping stroke may be quickly adjusted from½” to 2½’ by revolving the eccentric. Available in simplex and duplex types.

Lowhead Diaphragm Pump Capacity


Suction-Pressure Diaphragm Pump

Pump, Diaphragm, Suction-Pressure

Suction-Pressure Diaphragm Pump is the solution to pumping problems which involve the handling of all types of pulps and slurries, particularly where elevating material to a point higher than is possible with an open discharge diaphragm pump.

Pumping against a discharge head up to 20 feet is possible with this unit. It is also an ideal filtrate pump for discharging the solution from a filtrate receiver in the vacuum circuit of a filter system where the vacuum is not greater than 15 inches of mercury. The fine solids that are often present in filtrates will seriously damage an ordinary centrifugal solution pump, but are handled without trouble by the Suction-Pressure Diaphragm Pump due to its outstanding design features and adaptability.

Carefully engineered throughout, this pump is simple in design and operation. The ¾” size has a single heavy rubber diaphragm and is available in the simplex type only. The 1¼”, 2″, and 4″ sizes have two heavy, molded rubber diaphragms, and are available in simplex, duplex, triplex, and quadruplex types. Thus, almost any range of capacities desired can be obtained by varying size and type.

The vertical flow pulp through the pump and the vertical position of the diaphragms make it impossible for air, which would decrease the pump’s efficiency, to collect in pockets. Also, when a diaphragm wears out or breaks, there is no spray or splash of pulp outside the pump as in ordinary suction-pressure pumps. This is important in preventing injury to operators when pumping caustic pulps.

Variation in stroke on all sizes is made possible by means of an adjustable eccentric, and on the 1¼”, 2″, and 4′” sizes the capacity may be further regulated by admitting air during the suction stroke—through a small needle valve—this having the effect of varying the suction and therefore allowing finer capacity adjustments.

Both belt driven and motor driven units are available. All sizes are equipped with replaceable rubber valve seats. Valves and valve seats are readily accessible from the side opposite the diaphragm, without disturbing the diaphragm, by simply unbolting the pump’s removable side plate. Ball valves are standard on the 34″ size and tapered valves with replaceable rubber wearing faces are standard on the larger sizes.

Suction-Pressure Diaphragm Pump Capacity

CapacityPump Size

Adjustable Stroke Diaphragm Pump

Diaphragm Pump Working Principle

The Adjustable Stroke Diaphragm Pump is a diaphragm type suction pump designed to operate on high density pulps or slurries. The vertical movement of the large diaphragm is obtained by means of an eccentric on the shaft and a connecting rod acting through a fulcrum and plunger rod toggle which imparts a vertical motion to the plunger rod connected to the diaphragm.

Stroke Adjustment

A 100 percent variation in pump capacity while the pump is operating is possible by adjusting the position of the connecting rod on the fulcrum by means of a conveniently located handwheel. This is very important in pumping thickener underflow as it enables the operator to compensate for fluctuating feed and thus to maintain the highest possible per cent solids in the thickened material.

Diaphragm Life

The life of the molded rubber diaphragm used on the Adjustable Stroke Diaphragm Pump varies from one to four years depending upon the pumping problem. A pump operated at minimum stroke against a low suction lift will require less frequent diaphragm replacement than a pump operating at maximum stroke against a high lift. Side flexing of a diaphragm will shorten the life, and on pumps, this is eliminated by imparting only a vertical motion to the plunger rod.

Diaphragm Pump

Diaphragm Pump Capacity

Theoretically, the capacity of the diaphragm pump is in direct proportion to the cubic displacement of the diaphragm and the strokes per minute of the pump. This is the basis for most diaphragm pump capacity tables; however, in actual operation there are other influencing factors.

In pumping thick pulp through short suction lines against a high suction lift, a pump often handles less than the theoretical capacity. On the other hand, when pumping more fluid pulp through long suction lines against a low suction lift, a pump may handle double the theoretical capacity due to the momentum of the pulp in the suction line.

Two methods are provided for changing the capacity of Adjustable Stroke Diaphragm Pumps while in operation:
1. Adjustment of stroke by handwheel.
2. Admitting air beneath the diaphragm by means of a needle valve.

Height of Lift

Normally the maximum lift of a diaphragm pump is limited to that corresponding to 14′ of water at sea level. This amounts to a lift of approximately 8′ when pumping pulp containing 50% solids when the specific gravity of the dry solids is 2.65. The lower the lift, the longer the diaphragm life. In actual installations, whenever possible, a diaphragm pump is mounted with the lower valve located at a point from two to four feet above the water level of the thickener.

Diaphragm Pump Specifications

The Standard Diaphragm Pump is a heavy duty machine designed for continuous 24-hour operation. Required headroom is low, and parts are easily accessible. Bronze bushed hinge points and babbitted main bearings are used, and provided with alemite industrial fittings for pressure lubrication. Pump bowl can be set to discharge in any of the four quadrants. Further detail includes rubber faced valve assemblies, and valves which can be removed while the pump is in operation; bronze eccentrics with steel straps; and special molded rubber diaphragms.

Special alloys and synthetic rubber can be furnished to handle hot or corrosive solutions and pulps. This makes the Adjustable Stroke Diaphragm Pump particularly well suited to use in the chemical industry.

Adjustable Stroke Diaphragm Pump 2 inch size

2 inch Size

Adjustable Stroke

Adjustable Stroke Diaphragm Pump 3 and 4 inch sizes

3 and 4 inches

5 and 6 Inches

Adjustable Stroke Diaphragm Pump for Positive Control easily quickly adjusted while pump is running


Positive control with the easily adjusted Adjustable Stroke Diaphragm Pump gives more uniform and higher density pulp discharge from thickeners and hydroclassifiers.

Feed from Classifier

This pump is ideal for providing steady feed to flotation circuit when rate of feed to mill fluctuates.


Adjustable Stroke Diaphragm Pump has proved to be very successful in overcoming the difficulties normally encountered with centrifugal filtrate pumps.

Diaphragm Pump’s Pumping Capacity


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