In order for a filter press to function properly the selection of a feed pump is very important. Most Pump Engineers recommends the use of three different styles:
- Air Diaphragm pumps
- Centrifugal pumps
- Progressive cavity pumps
The pump must be capable producing the calculated flow at the maximum pressure for which the press is rated (typically100 psi (7.5bar) or 225psi (16bar). This flow and pressure must be able to be controlled pneumatically or electrically to gradually build up a filter cake in the filter chamber. The slurry pump must also be rated to handle large solids, heavy slurries and abrasive solids.
: Air Diaphragm Pumps :
Air diaphragm pumps are ideal for feeding heavy sludges into filter presses. This low cost, simple to maintain pump uses compressed air to operate and can be provided with an incremental pressure controller to form a dryer cake.
Air diaphragm pumps are designed to operate by compressed air and are capable of pumping heavy slurries. The main advantage is that an air piston diaphragm pump can be in a “stall” condition and not “burn up”. This stall feature is used to compact solids firmly into the filter chamber. The addition of a pump controller enables this stall time to be programmed as a feature in an Automatic Pump Controller.
: Press Mounted Pumps :
For convenience of installation an as a space saving measure air diaphragm pumps are offered as a mountable feature on
most smaller filter presses up to 800mm in size.
Most centrifugal pumps on the market will not work for filter press applications. The advantage of a centrifugal pump is that the flows are capable of several hundred GPM while being very cost effective. A number of different alloys are available for chemical compatibilities and abrasion resistance castings.Centrifugal pumps are very efficient pumps to use for Pre coating of materials such as Diatomaceous Earth.