Application of Vacuum Pumps Matched with Filter Presses

1.Applicable equipment models

Vacuum pumps are mainly matched with vacuum belt filter presses and vacuum plate-and-frame filter presses. Some membrane chamber filter presses are also equipped with auxiliary vacuum suction systems. Ordinary plate-and-frame filter presses without vacuum structures are generally not fitted with vacuum pumps.

2.Core functions

Negative pressure is generated by the pump set to extract free capillary water inside filter cakes through filter cloth, strengthening solid-liquid separation and reducing the moisture content of filter cakes. Meanwhile, water vapor and a small amount of volatile gas inside filter chambers can be evacuated to improve filtration efficiency.

3.Commonly adopted pump types

Water ring vacuum pumps and Roots-water ring vacuum units are the mainstream options in the industry. Single-stage water ring vacuum pumps suit small and medium-sized filter equipment, with resistance to water vapor and minor dust. Roots-water ring units deliver higher negative pressure and larger pumping speeds, applicable to large-capacity industrial filter production lines. Dry vacuum pumps are rarely used for vacuum suction of filter presses, as they are vulnerable to damage from water vapor and fine powder.

4.Supporting auxiliary components

A gas-liquid separator and buffer tank must be installed at the front end of vacuum pipelines to intercept filtrate and solid powder, preventing corrosion and blockage of vacuum pumps caused by direct ingress of liquid and impurities. Pneumatic valves and vacuum pressure gauges are equipped on pipelines to monitor negative pressure values in real time.

5.Operating process logic

After feeding and preliminary squeezing of the equipment, the vacuum pump starts to build negative pressure for dewatering by suction. Upon completion of the vacuum filtration process, the vacuum valve is closed first to release negative pressure before discharging materials. The vacuum pump starts and stops in linkage with the main filter press and operates intermittently in sections instead of continuous full-cycle running.

6.Working condition adaptability

Suitable for dewatering sludge, ore pulp, chemical slurry and fine powder materials. It can handle filtration working conditions with water vapor and slightly corrosive volatile media. Compared with squeezing alone, dewatering assisted by vacuum negative pressure delivers drier filter cakes and lowers the load of subsequent drying equipment.

7.Usage limitations

Vacuum pumps only undertake negative pressure dewatering and cannot convey materials for feeding. They fail to generate high-pressure extrusion effects and cannot replace feed pumps or membrane squeezing media. There is an upper limit for vacuum degree; dewatering merely relying on vacuum pumps achieves limited effects for high-viscosity and sticky materials.