Product introduction of plate and frame filter press
Plate and frame filter press is the first machine used in chemical dehydration. Although plate and frame filter presses are generally operated intermittently, with large investment in infrastructure equipment and low filtration capacity, but because of their strong filtering force, high solid content of filter cake, clear filtrate, high solid recovery, and conditioning drugs The advantages of low consumption, etc., are still widely used in some small sewage plants.
Working principle of plate and frame filter press
After the sludge is concentrated and digested, it still has a moisture content of about 95% to 97%, and its volume is still large. Sludge dewatering can further remove the interstitial water and capillary water in the sludge and reduce its volume. After dehydration treatment, the moisture content of the sludge can be reduced to 70% to 80%, and its volume is 1/10 to 1/4 of the original volume, which is conducive to subsequent transportation and treatment. The mechanical dewatering methods of sludge include filtration dewatering, centrifugal dewatering, and squeeze dehydration. Filter dehydration includes vacuum filtration and pressure filtration; centrifugal dehydration uses dehydration by a centrifuge; dehydration by dehydration uses a screw press or a roller press. . Common methods are pressure filtration and centrifugal dewatering.
The sludge filtration and dehydration is based on the pressure difference between the two sides of the filter medium as the driving force, so that the sludge water is forced to pass through the filter medium to form a filtrate, and the solid particles are trapped on the medium to form a filter cake, thereby achieving the purpose of sludge dehydration. Plate and frame filter press is the first machine used in chemical dehydration. Although plate and frame filter presses are generally operated intermittently, with large investment in infrastructure equipment and low filtration capacity, but because of their strong filtering force, high solid content of filter cake, clear filtrate, high solid recovery, and conditioning drugs The advantages of superior consumption are still widely used in some small sewage plants.
Plate and frame filter press product structure
The structure of the filter plate, filter frame and filter cloth of the plate and frame filter press is shown in Figure 1, where (a) is the filter frame, (b) is the filter plate, and (c) is the filter cloth. The structure of the plate and frame filter press is shown in Figure 2. The layout of the plate and frame filter press and its auxiliary equipment is shown in Figure 3. In addition to the plate and frame filter press mainframe, there are mud inlet systems, dosing systems and compressed air systems.
Plate and frame filter press product dehydration process
The plate and the frame are arranged alternately, and filter cloth is covered on both sides of the filter plate, and the plate and the frame are compressed with a pressing device, that is, a filter press chamber is formed between the plate and the frame. A small hole is opened at the same position in the middle of the upper end of the plate and the frame. After compaction, it becomes a channel. The sludge pressurized to 0.2 ~ 0.4MPa enters the filter press chamber through this channel. The surface of the filter plate is engraved with grooves and the lower end. A hole is drilled for discharging the filtrate, and the filtrate is discharged under a pressure through a filter cloth, along the groove and the hole, to dewater the sludge.
Automatic plate and frame filter presses have been developed at home and abroad. Plate and frame filter presses can withstand higher sludge specific resistance than vacuum filters, so that the consumption of conditioning agents can be reduced, and cheaper chemicals (such as FeSO4 · 7H2O) can be used. When the specific resistance of the sludge is 5 × 1011 ~ 8 × 1012m / kg, it can be directly filtered without prior conditioning. The mud cake yield and mud cake moisture content of the plate and frame filter press shall be determined based on test data or similar operating experience. The moisture content of mud cake can generally be 75% ~ 80%.
Food industry applications:
Juice drinks, rice wine beer, white wine, yeast, plant protein, cyclamate, glucose, starch sugar, maltose, starch, rice flour, carrageenan, monosodium glutamate, flavor, soy sauce, oral liquid
Chemical industry applications:
Fuel pigment, caustic soda, soda ash, chlor-alkali salt, white carbon ink, soap violet, fennel ink, bleaching powder, Lide powder, fluorescent powder, insurance powder, potassium chlorate, potassium sulfate, ferrous sulfate, iron hydroxide, water purifying agent, sulfuric acid Aluminum, polyaluminum chloride, basic aluminum chloride
Applications in the pharmaceutical industry:
Antibiotics: erythromycin, spiramycin, tetracycline, oxytetracycline, etc .; Chinese medicine: inositol, organophosphorus, glycated alcohol, etc.
Application in metallurgical industry:
Molybdenum, iron, zinc, copper, silver, gold, etc.
Applications in the refining industry:
Butter, petroleum, cooking oil, glycerin, vegetable oil, machinery oil, etc.
Application of sewage treatment industry:
Liquid-solid separation of chemical wastewater, smelting wastewater, printing and dyeing wastewater, pharmaceutical wastewater, etc.
Five advantages of plate and frame filter press:
① The slag discharge through the pneumatic valve can greatly reduce the labor intensity of workers;
② Without the use of filter cloth and filter paper, the cost of filtration can be greatly reduced;
③Using fully enclosed operation mode, very environmentally friendly, and there is no material loss;
④ When the slag is shaken by vibration, the labor intensity can be greatly reduced to achieve continuous operation;
⑤ When the slag and activated carbon in the liquid are filtered and dehydrated, it can also replace the plate and frame filter, which is the first choice in the filtration industry.