A basic overview of plate and frame filter presses

As a solid-liquid separation equipment, the filter press has a long history of being used in industrial production, and it has good separation effect and wide adaptability, especially for the separation of viscous materials, it has its unique advantages.

The filter press is divided into plate and frame filter press and chamber filter press, and the filter press is a batch filtration equipment used for the solid-liquid separation of various suspensions. It relies on the pressing device to press the filter plate, and then the suspension is pressed into the filter chamber with a pump, and the purpose of separating the solid particles and liquid particles is achieved through the filter cloth.

The plate and frame filter press is a very mature dewatering equipment, which is used in the early sludge dewatering projects in Europe and the United States, the structure of the plate and frame filter press is simple, easy to operate, stable, the selection range of filtration area is flexible, the unit filtration area occupies less area, the filtration driving force is large, the moisture content of the obtained filter cake is low, the adaptability to the material is strong, and it is suitable for all kinds of sludge.

The filter press belongs to the batch solid-liquid separation equipment, if the filter press is analyzed according to the large category, the model can be divided into plate and frame filter press, chamber filter press and chamber diaphragm filter press, which is often referred to as plate and frame filter press or plate and frame machine in the industry.

Plate and frame sludge filter press is a kind of batch solid-liquid separation equipment, the filter chamber is composed of a filter plate and a filter frame in sequence, and the material is sent into each filter chamber from the conveying pipeline by the feed pump. Under the action of pressure, the moisture in the material will flow through the filter cloth into the discharge pipe, becoming a clear liquid without solids. The material filter cake will be trapped in the filter chamber and gradually accumulate in the filter chamber to form a filter mud cake, so that the solid and liquid can be separated.

With the filtration work, the filter cake filtration begins, the thickness of the mud cake gradually increases, and the filtration resistance is relatively increased. The longer the filtration time, the better the separation, also known as pressure holding.

In addition to the excellent separation effect and high solid content, the plate and frame filter press can also be combined with a backwash system during the filtration process to effectively wash the filter mud cake. As a result, valuable substances can be obtained** and high-purity filter mud cakes can be obtained.

The two models of plate and frame filter press and belt filter press are quite mature models, and the two models are widely used in urban sewage, pharmaceutical and pharmaceutical, petrochemical, food processing, metallurgy, mining and other industries.

The different structures of the two models also lead to the different filtration methods of the two models, and the working process of the plate and frame filter press is: feed pump feeding-filtration-pressing material-discharge. Now in order to get rid of the manual unloading of the old model, the automatic control does not need manual guarding.

Compared with the belt filter press, the single filtration time is longer, and it belongs to the intermittent work type. However, the water content of the treated sludge is low and the filtration effect is good.

Belt filter press: The belt filter press can work continuously, and the processing capacity of materials per unit time is large (the treatment capacity is not much different from the plate and frame filter press in the case of the same specification), and it is used more in large sewage treatment plants or water plants. However, because the moisture content of the treatment is high, it needs to be reprocessed in the later stage, so many users have slowly replaced the plate and frame machine, and the maintenance of the machine is inconvenient in the later stage.

The advantages of plate and frame chamber filter press are simple structure, easy manufacturing, compact equipment, large filtration area and small footprint, high operating pressure, low water content of filter cake, strong applicability to various materials, and suitable for various small and medium-sized sludge dewatering treatment occasions. The disadvantage is that the feed port of the filter frame is easy to block, the filter cake is not easy to take out, it cannot run continuously, the processing capacity is small, the working pressure is low, the ordinary material square plate is not pressure-resistant, it is easy to break the plate, the filter cloth consumes a lot, the plate and frame are difficult to be unattended, and the filter cloth often needs to be cleaned manually. Plate and frame filter press is a kind of filter chamber composed of filter frames, under the action of pressure, the filter medium is used to separate the solid and liquid equipment.

It is made of reinforced polypropylene filter plate, filter frame molded by patented technology, high strength, light weight, corrosion resistance, acid and alkali resistance, non-toxic and tasteless, its design is reasonable, simple structure, reliable performance, easy to use, easy to maintain, can be applied to chemical, petroleum, metallurgy, pharmaceutical, food and environmental protection and other industries of solid-liquid separation process. Versatile and adaptable. Advantages and disadvantagesThe shortcomings of the plate and frame filter press are that the feed port of the filter frame is easy to be blocked, the filter cake is not easy to take out, it cannot run continuously, the processing capacity is small, the working pressure is low, the ordinary material square plate is not resistant to wheel finch pressure reduction, easy to break the plate, the filter cloth consumes a lot, the plate and frame are difficult to be unattended, and the filter cloth often needs to be manually cleaned up over the years.

The advantages of plate and frame filter press are: simple structure, easy operation, stable operation and convenient maintenance; The selection range of filtration area is flexible and occupies a small area; It has strong adaptability to materials and is suitable for various occasions of small and medium-sized sludge dewatering.

Compared with the plate and frame filter press, the belt filter press is a water treatment equipment introduced from the United States, digested and absorbed, and successfully developed, which can work continuously and filter a large amount of sludge continuously, and the product is made of high-strength materials, which has the characteristics of large processing capacity, high dehydration efficiency and long service life, and is widely used in the treatment of various industries, and its configured bearings have a long service life. However, the filter cake after sludge dewatering of the belt filter press has high water content, high energy consumption, and is difficult to maintain during use.

The work of the plate and frame filter press adopts intermittent operation, and after running a complete process, it enters the next transportation feeding, filtration, pressing and drying, and discharging. Therefore, some equipment needs to be completed manually, and the filter cloth needs to be replaced, which affects the efficiency of the filter press equipment.

However, the plate and frame filter press is a very mature dewatering equipment, which is suitable for all kinds of sludge. The plate and frame filter press is mainly composed of thrust plate, filter plate, compression plate, girder and pressing device. The materials used to make the plate and frame are metal, wood, engineering plastics and rubber, etc., and there are various forms of filter plate surface grooves as the drainage channel, and the filter frame is hollow.

A plurality of filter plates and filter frames are arranged alternately, filter media (such as filter cloth) are sandwiched between plates and frames, filter frames and filter plates are erected on two equal beams horizontally through two lugs, one end is a thrust plate, and the hold-down plate at the other end is pressed or pulled apart by a hold-down device during work.

Belt press filter press: continuous work, belt press dewatering machine has 3 working areas, namely gravity dewatering area, wedge press dewatering area and shear press dewatering area, its pressing type belongs to two-dimensional pressing, mainly used for sludge dewatering, but its application range is expanding.

Plate and Frame Filter Press: Intermittent pressurized filtration equipment for solid-liquid separation of various suspensions.

1.Belt sludge dewatering machine.

The belt sludge dewatering machine is made of two tensioned filter belts up and down to carry the sludge layer, passing through an S shape from a series of regularly arranged roller cylinders, relying on the tension of the filter belt itself to form the pressing and shearing force on the sludge layer, squeezing out the capillary water in the sludge layer to obtain a mud cake with high solid content, so as to realize sludge dewatering.

Generally, the belt sludge dewatering machine is composed of a filter belt, a roller cylinder, a filter belt tensioning system, a filter belt deviation adjustment system, a filter belt flushing system and a filter belt drive system. In , the common value is 0 5MPa.

The belt sludge dewatering machine is less affected by sludge load fluctuations, and also has the characteristics of low sludge moisture content, stable work and low consumption, relatively simple management and control, and low quality requirements for operating personnel. At the same time, due to the earlier entry of belt sludge dewatering machine into China, a considerable number of manufacturers can produce this kind of equipment. When making decisions on the construction of sewage treatment projects, belt sludge dewatering machines can be selected to reduce project investment.

At present, most of the newly built sewage treatment plants in China use belt sludge dewatering models.

2.Plate-and-frame sludge dewatering machine.

The plate-and-frame filter press is to make the water in the sludge be discharged through the filter cloth through the extrusion of the plate and frame to achieve the purpose of dewatering. It is mainly composed of a concave filter plate, a frame, an automatic-pneumatic closure system, a plate suspension system, a filter plate vibration system, an air compression device, a filter cloth high-pressure washing device and a photoelectric protection device on one side of the fuselage.

The belt filter press is mainly used to treat the sand field or sludge with large output, the filter press can work continuously for a long time, the treatment capacity is large, the dehydration effect, and the water content of the slurry pressed out by the filter press is about 30%.

The similarities between plate and frame filter press and belt filter press: plate and frame filter press and belt filter press equipment are widely used, in urban sewage treatment, food processing, petrochemical industry, metallurgical manufacturing, mining and mining, metal forging, pharmaceutical industry, electronics industry, chemical industry and other industries. **Reusables, treatment of wastewater, protection of the environment.

Performance comparison: The plate and frame filter press has a simple structure and powerful functions, which basically meets the requirements of all walks of life. However, compared with the belt filter press, it has the following characteristics:

1. The work of the plate and frame filter press adopts intermittent operation, that is, after running a complete process, it can enter the next operation, namely: feeding - filtration - pressing and drying - discharging. Therefore, some equipment requires manual cooperation to complete, which increases the probability of human damage to the equipment.

2. There is an additional process of replacing the filter cloth, and the replacement of the filter cloth in the chamber filter press is more complicated, and the nature of the filter cloth will also affect the regeneration of the filter cloth, thereby affecting the efficiency of the filter press equipment.

3. The filter residue moisture of the plate and frame filter press is lower than that of the belt type, which can generally reach the range of 30%.

As the name suggests, the filter residue filtered by the belt filter cloth is continuously discharged, so that the belt filter press works continuously and has high filtration efficiency. But unlike plate and frame filter presses:

1. The market is high and the equipment is huge.

2. The filtered filter residue has high moisture, which can only be about 45% in general.

After the belt filter press, it can be connected to the non-thermal drying technology to reduce the moisture content to 40% and incinerate; The plate and frame filter press is not conducive to incineration due to the addition of lime.

Nico Environmental Technology **** sludge non-thermal drying technology, using non-heating method to dewater and dry sludge, only 10 minutes to reduce the moisture content of sludge from 85%-80% to 55%, and then through the forced ventilation drying technology in the non-heated state, the moisture content in the sludge continues to reduce to 40%, and the energy consumption is only 10% of thermal drying, and the treatment process will not produce odor.

Sludge heatless drying technology" has overcome the worldwide problem of high energy consumption and odor generation of sludge drying. Another striking result is that the dried mud cake has a fairly high calorific value.

Due to the drying process without heating, the loss of organic matter in the sludge is avoided. The biomass fuel made from the dried mud cake has been tested by the authoritative department, and the actual detection effect of the sludge heatless drying project of the MCC Sewage Treatment Plant in Funing District, Qinhuangdao is taken as an example, and the calorific value reaches 3826 kcal, which is higher than that of lignite, and the sludge is truly turned into "coal". It realizes the principle of circular economy advocated by the state, and truly realizes the reuse of resources for sludge treatment and disposal.

Belt filter press coefficient reference"> detailed factor reference.

Working condition: continuous dehydration.

Equipment advantages:1The machine is easy to manufacture, with few auxiliary equipment and low energy consumption; 2.Continuous operation, easy management, large dehydration capacity. 3. The equipment is prone to failure, and the cost of fault maintenance is relatively high.

Equipment disadvantages:1The polyacrylamide content used with it is high, expensive and the operating cost is high; 2.The dewatering efficiency is not as good as that of the plate and frame filter press.

Scope of application:1It is especially suitable for the dewatering of inorganic sludge; 2.Organic sludge is not suitable.

Plate and frame filter press detail coefficient reference.

Working condition: intermittent dehydration.

Equipment advantages:1Low moisture content of filter cake; 2.High rate of solids; 3.The consumption of polyacrylamide agents is low.

Equipment disadvantages:1It is an intermittent operation, and the workload is relatively low. 2.The filter cloth needs to be changed regularly.

Scope of application: Enterprises, especially those with high dewatering requirements, want to reduce the volume of sludge as much as possible to reduce the cost of later disposal.

Filter press"> belt press.

1. Feeding position: The common feeding method of the chamber filter press is intermediate feeding, and some old equipment is middle and upper feeding, or angle feeding; The feed of the plate and frame filter press is all corner feed.

2. Filter plate structure: The chamber filter plate is an integral filter plate. The plate-and-frame filter plate is a combination of two plates, one frame, and two pieces.

3. Filter material: The filter material of the chamber filter press is mainly filter cloth; The filter material of the plate and frame filter press has a variety of options such as filter cloth, filter paper, and filter membrane.

4. Degree of automation: the plate and frame filter press cannot achieve automatic operation regardless of the size; The chamber filter press can be operated automatically. This is mainly due to the different structure of the filter plate of the filter press.

To sum up, the working principle of the chamber filter press and the plate and frame filter press, the structure of the filter press is basically the same, and the biggest difference is the difference between the filter plates.

Belt press.

The difference between machine and plate and frame filter press"> difference between belt filter press and plate and frame filter press.

How it works. The belt machine mainly performs the function of filtration and dewatering in three steps (taking sludge dewatering as an example).

Gravity dehydration. After the sludge of the sewage treatment plant is pumped into the sludge mixing tank and mixed with the polymer coagulant, the fine suspended particles in the sewage are formed into large rubber plume particles by the bridging action of the polymer coagulant, and then flow into the sludge distribution device of the dewatering machine from the upper end of the agitation in a self-flowing manner, so that the granular sludge is evenly distributed on the filter screen of the gravity dewatering zone. The function of gravity concentration dewatering zone is to make the free water outside the block sludge be discharged by gravity through the mesh of the filter cloth, so as to increase the sludge concentration, make the block sludge properties tend to be stable, and facilitate the subsequent pressing and dewatering operation.

Pressure dehydration. After the sludge enters the pressure dewatering zone from the gravity dewatering zone, the upper and lower filter cloths begin to gradually pressurize the sludge to dewater.

Pressurized dehydration. The sludge moves into the pressurized dewatering zone with the filter cloth, between the 6 vertical rollers, according to the diameter of the rollers from large to small, the pressure is effectively gradually increased, and the upper and lower filter cloths are sheared on the sludge due to the change of the upper and lower positions of the filter cloth between different rollers, and the capillary tube in the sludge is pressed out in combination with water to produce a drier sludge cake.

Feature 1: Low power consumption and large processing capacity;

2. The dehydration efficiency is average, and the solid content of mud cake is average;

3. Simple operation and management, easy to maintain;

4. High degree of automation, continuous production;

5. Low noise and long service life;

6. Less auxiliary equipment, economical and reliable, with a wide range of applications.