Working principle and precautions of Hengshui diaphragm filter press

The diaphragm filter press is a filter press with an elastic membrane installed between the filter plate and the filter cloth. During use, after the feeding is completed, high-pressure fluid or gas medium can be injected into the diaphragm plate, and then the entire diaphragm will expand and squeeze the filter cake to further dehydrate the filter cake, which is commonly known as filter pressure.

Working Principle of Diaphragm Filter Press

The main difference between the diaphragm filter press and the ordinary box filter press is that an elastic diaphragm plate is installed between the filter plate and the filter cloth. During operation, when the feeding is completed, a high-pressure fluid medium can be injected between the filter plate and the diaphragm, and then the entire diaphragm will expand and squeeze the filter cake, thereby achieving further dehydration of the filter cake, that is, filter pressing.

The first is positive pressure dehydration. A certain number of filter plates are closely arranged in a row under the action of strong mechanical force, forming a filter chamber between the filter plates. The filtered material is sent into the filter chamber under strong positive pressure. The filter medium intercepts the solid part of the filtered material to form a filter cake, while the liquid part is discharged from the filter chamber through the filter medium, achieving solid-liquid separation. With increased positive pressure, the separation becomes more thorough.

However, considering energy and cost, after slurry dehydration, the filter press equipped with a rubber extrusion membrane allows the compression medium to enter the rear of the extrusion membrane, pushing it to further dehydrate the filter cake. After slurry dehydration or squeezing, compressed air enters one side of the filter cake, penetrates it, and carries liquid water out of the filter chamber through the filter cloth. The liquid is evenly discharged through both sides of the filter chamber. If the filter cloth is coated on both sides, this is called double-sided dehydration. After dehydration, the mechanical pressure of the filter plate is released, the filter plates are gradually pulled apart, and the filter chamber opens for cake unloading.

According to the properties of different materials, the filter press can be equipped with slurry dehydration, squeeze dehydration, blast dehydration, or single/double-sided dehydration, all aimed at reducing the moisture content of the filter cake.

Precautions for Using the Diaphragm Filter Press

1. Operators must strictly follow the manual for operation, adjustment, usage, and maintenance and be familiar with its contents.

2. The filter cloth should not be damaged, and high-quality filter cloth should be selected. The sealing surface should be free of wrinkles or overlaps.

3. Regularly check the safety of all machine parts, inspect the hydraulic system for oil leaks, ensure fasteners are tightened, and verify that transmission parts operate flexibly and reliably.

4. Regularly check the quality and purity of hydraulic oil and ensure the oil level meets requirements. Keep the hydraulic system clean, waterproof, and dustproof.

5. After each startup, carefully observe the machine’s operation. If any abnormalities occur, stop the machine immediately for maintenance.

6. During operation, the filtration pressure, compaction pressure, and liquid temperature must not exceed specified values. It is strictly forbidden to start the filter press without plate racks or if the pressing plate displacement exceeds the piston stroke.

Advantages of the Diaphragm Filter Press

The diaphragm filter press achieves efficient dehydration, ensuring optimal filtration performance and significantly reducing the moisture content of the filter cake. After feeding, the dehydration efficiency is improved by squeezing the filter cake, increasing its dryness, reducing pollution, and lowering labor intensity. In some processes, the drying step can even be eliminated, further enhancing operational efficiency.