Here is cone crusher arranged with a Level Sensor interlocked with the feed conveyor.  It keeps the crusher feed cavity full for best choke feeding.

This is a great way how you can choke feed a cone and crush for a finer product.

You do know that choke feeding reduces liner wear? See why in this video.

I often see operators running their crushers at 65 percent. It seems to be a common comfort level. They definitely don’t push them as hard as they can be pushed.” Osborn says there is a fine line between use and abuse. But to get more production out of a cone crusher, the operator must look at the closed-side setting (CSS) and ask what he or she is getting out of the crusher, as well as what is returning. An operator might see that the crusher
is running at 80 percent, but it’s also getting 35 percent going back through the chamber. “The cone is shaped like an egg,” he says. “It’s natural to get some return. But you want to try and get that return to 20 to 25 percent.”
Osborn explains that operators can gauge their return by shutting off the raw feed to the cone and analyzing what is returning to it as recirculated feed. “If you’re making 3/4-inch aggregate and the cone is set at 1-inch, you’re not using it well,” he says. “If you’re making 3/4-inch or 5/8-inch material, don’t set the cone at 1-inch. But you’d be amazed. So many times, I ask an operator, ‘What’s the cone set at?’ And he’ll guess: ‘Oh, 3/4-inch.’ And he’s wrong.” Osborn notes that automation technology has made a difference with this challenge. But he says it’s frustrating that many long-time operators will not use the technology that is available to help them with their crusher settings.
“You take away their push buttons, and they’re lost. But use the technology. The readouts will tell you what your CSS is.
Often, it can adjust CSS automatically,” he adds. Proper preventive maintenance is another key to getting the best and most production from crushers, Osborn says. And he feels at the very root of this practice is familiarity with the machine, which will make daily pre-shift walkaround checks more meaningful. “If you know your machine, you’ll know the signs that something is wrong,” he says, adding that proper greasing and regular oil sampling
will also keep machines running well. “Every single time we’ve ever lost a bearing or had a failure, there was some sort of indicator before the fact that we didn’t catch,” Osborn explains. “If you do an oil analysis and there’s brass in the oil, it raises a red flag.

Because every deposit is unique, the variables that affect crusher and liner choices can be numerous to achieve the desired product. But he says, in addition to feed and closed-side setting (CSS), operators can also change the revolutions per minute (RPM) speed of a cone to improve performance. Smith explains that increasing the speed of the eccentric retains material longer in the chamber. This will increase production of fine material, consume less power, increase crushing efficiency of the desired gradation, and produce more quality (cubical) material. The tradeoff can be reduced volumetric throughput. “All things being equal, at a 1-inch CSS, you’re going to produce a higher percentage of minus 1-inch material in a single pass at a higher crushing speed,” he says. “The opposite is true at lower crushing speeds.” But even when the crushers are running at their fullest potential, an inefficient screen can bottleneck the entire operation. Because a cone crusher typically represents the most expensive asset in the system, a plant should be designed so that the bottleneck is at the last crusher in the circuit, not the screen. “If you’re optimizing crushers, you also have to optimize screens,” Smith says. “If a 200-ton-per-hour screen deck is suddenly asked to produce at 300 tons per hour, you’re going to overload the screen. It won’t be able to separate the undersize material, and that undersize rock will carry across the end of the screen, recirculating back to the cone. The only way you can get that material to the pay pile is to get it through the screen surface.” Obviously, more screen area spreads the load better and gives the material more time to stratify. But not every situation requires a new screen to match a crusher’s increased capacity. Other variables that can affect a screen’s efficiency include the speed, as well as the length, type direction, and angle of its “stroke,” or throw. “By design, screens are out of balance,” Smith says. “The speed and stroke pattern can be manipulated to affect how material behaves on the screen.” “Coarser screening applications generally favor a more aggressive, slower speed and a longer, steeper stroke. A longer stroke generates higher Gs needed to dislodge coarse particles from screen openings. Finer applications favor a thinner bed depth, which is achieved by higher speeds and flatter, shorter stroke patterns. Finer material needs more contact with the screen surface, and a shorter stroke does not allow material to bounce as high,” Smith says. “There’s a science and an art to improving your crusher.