Conclusion first: With the secondary pressing process of expandable diaphragm, the moisture content of filter cake can be reduced to less than 40% at most, and the dehydration efficiency is significantly improved.
Case study: After a chemical plant in Jiangsu introduced this machine, the annual sludge processing volume increased by 20% and the cost of chemicals was reduced by about 300,000 yuan.
As environmental regulations become increasingly stringent, printing and dyeing, chemical, mineral processing and other industries have put forward higher requirements for solid-liquid separation equipment. The moisture content of filter cakes from traditional filter presses is usually between 50% and 60%, while the membrane filter press achieves secondary squeezing by installing an expandable diaphragm on the filter plate, further reducing the moisture content to ≤40%, greatly reducing the subsequent drying or incineration costs. The following content provides you with an in-depth analysis of the process, components, applications and selection recommendations.
1. New interpretation of process flow
1. Feed filtration: Under pre-pressure of 35–50 kPa, the slurry is introduced into the machine body to form a preliminary filter cake.
2. Secondary pressing: After closing the slag discharge valve, use 0.3-0.6 MPa of air (or water) pressure to act on the diaphragm to continuously squeeze out the remaining water for 3-5 minutes.
3. Cake unloading and cleaning: After the filter cake is formed, the filter plate unloading mechanism is automatically opened, the filter plates are separated, and the filter cake falls off; back washing or surface washing process can be selected to improve the purity of the filter cake.
2. Core Components and Technical Highlights
– Diaphragm filter plate: 304 stainless steel frame wrapped with food grade polyethylene diaphragm, corrosion resistant and easy to clean.
– Intelligent hydraulic system: closed-loop control valve group, real-time adjustment of squeezing pressure and time, pressure fluctuation ≤±2%.
– High-performance filter cloth: Polyester filament filter cloth with customizable pore size (0.2–5 μm) effectively prevents clogging by fine particles; the sealing ring is made of wear-resistant nylon material with a service life of over 20,000 cycles.
3. Application value and economic benefits
Industry scenario | Feed solid content | Filter cake moisture content | Typical benefits
Printing and dyeing wastewater treatment | ≥25% | ≤38% | Save about 120 yuan per ton of sludge post-treatment cost
Mine tailings dehydration | ≥30% | ≤42% | Annual drying energy saving over 15%
Food and medicine clarification and filtration | — | — | Clarity ≥ 99.8%, reducing the dosage of medicine by 10%
4. Selection Guide
Laboratory/pilot scale: throughput ≤ 0.5 m³/h, recommended filter plate size 400×400 mm, number of filter plates 10–20.
Industrial production scale: processing capacity ≥ 5 m³/h, 800×800 mm or 1000×1000 mm models are recommended, the number of filter plates is 20–40, and it is equipped with an automatic cake unloading system.
V. Conclusion
Under the dual pressure of cost and environmental protection, the membrane filter press is becoming the preferred equipment for solid-liquid separation in the fields of chemical industry, printing and dyeing, mining, food and medicine with its efficient secondary pressing capacity, intelligent control and modular design. When purchasing, enterprises should combine material characteristics, production capacity requirements and back-end processing procedures for comprehensive evaluation to achieve the best balance between dehydration efficiency and economic benefits.