Fully automatic diaphragm filter press

Yangzhou Huazhuo Filtration Equipment Co., Ltd. [Phone:] mainly produces and sells various specifications of automatic filters, bag filters, precision filters, pipeline filters, mechanical filters, plastic filters, filter cartridges, filter bags, membrane shells, water tanks, tanks, dust removal bags, gas purification filtration equipment and other accessories.

Product Introduction

A filter press is a mechanical device that uses a special filtering medium to apply a certain pressure to an object, causing liquid to be dialyzed out. It is a commonly used solid-liquid separation equipment. It was applied in chemical production in the early 18th century and is still widely used in industries such as chemical, pharmaceutical, metallurgy, dyes, food, brewing, ceramics, and environmental protection.

The filter plate has stable performance, easy operation, safety, and labor-saving; The metal squeezing cylinder is made of seamless steel pipe processing and precision casting of plastic steel filter plate, which is resistant to high temperature and high pressure and durable.

Basic Overview

Function: Extract solids from the mixed liquid to achieve the separation of solid and liquid.

Category classification:

A、 Classification of filtration methods: chamber pressure filter, belt pressure filter, diaphragm filter, plate and frame filter

B、 Structural classification: Suspended beam filter press and belt filter press

C、 Classification of pressure methods: hydraulic compression, manual jack compression, mechanical compression

The science used: the physics of solids and liquids.

Discipline: Coal Science and Technology (First level Discipline); Mining Machinery Engineering (Secondary Discipline); Coal Preparation Machinery (Third level Discipline)

History: The first filter press equipment appeared in the early 18th century and was used for chemical industry production.

Scope of use of filter press:

Environmental protection industries such as pharmaceuticals, chemicals, standard parts, pharmaceuticals, metallurgy, non-standard screws, dyes, food, brewing, ceramics, oil refining, and sewage treatment.

Technical Specifications

Model performance parameters

Filter area (㎡), filter plate dimensions (mm), filter plate thickness (mm), filter cake thickness (mm), number of filter chambers (pieces), theoretical volume of filter chambers (L), (m ³), overall dimensions of the machine (length x width x height) (mm), installation foundation dimensions (mm), working pressure inside the filter chamber (MPa), motor power (KW), overall weight (KG), filter plate performance, filter plate structure: plate frame type, box type filter plate

Filter plate materials: stainless steel, cast iron, rubber, reinforced polypropylene (plastic), polymer PE, etc

Other properties: acid and alkali resistance, filtration temperature (℃), filtration pressure (MPa)

Function Configuration

Manual compression, motor compression, automatic hydraulic compression, automatic pressure maintenance, electrical control/computer program control, automatic plate pulling, automatic liquid receiving flipping, etc

Feeding method and liquid flow form

Mid feed, corner feed, mid feed

Clear flowing liquid, dark flowing liquid

component

The structure of a filter press consists of three parts:

rack

The frame is the basic component of the filter press, with thrust plates and compression heads at both ends. The two are connected by large beams on both sides, which support the filter plate, filter frame, and compression plate. To meet advanced hygiene requirements, the rack needs to be wrapped in stainless steel. Stainless steel technology can be used as a reference, and its quality can meet the needs of European customers.

A、 Thrust plate: It is connected to the support to seat one end of the filter press on the foundation, and the middle of the thrust plate of the box filter press is for feeding

Holes, there are four corners and four holes. The holes in the upper two corners are for the inlet of washing liquid or compressed gas, and the lower two corners are for the outlet (whether it is a dark flow structure or a filtrate outlet)

b、 Compression plate: used to compress the filter frame of the filter plate, and the rollers on both sides are used to support the compression plate to roll on the track of the main beam.

C、 Main beam: It is a load-bearing component that can be coated with rigid polyvinyl chloride, polypropylene, stainless steel coating, or new anti-corrosion coatings according to the requirements of anti-corrosion in the usage environment.

Compression mechanism

Manual compression, mechanical compression, hydraulic compression.

A、 Manual compression: It is to use a spiral mechanical jack to push the compression plate to compress the filter plate.

B、 Mechanical compression: The compression mechanism consists of an electric motor (equipped with advanced overload protection), a reducer, a gear pair, a screw, and a fixed part

Composed of nuts. When compressing, the motor rotates forward, driving the reducer and gear pair to rotate the screw rod in the fixed nut, and pushing the compression plate to compress the filter plate and filter frame. As the clamping force increases, the motor load current increases. When it reaches the current value set by the protector, the maximum clamping force is reached, and the motor cuts off the power and stops rotating. Due to the reliable self-locking helix angle of the screw rod and fixed nut, the clamping state during the working process can be reliably guaranteed. When it retracts, the motor reverses. When the pressure block on the clamping plate touches the travel switch, it retracts and stops.

C、 Hydraulic compression: The hydraulic compression mechanism consists of a hydraulic station, an oil cylinder, a piston, a piston rod, and a connection between the piston rod and the compression plate

The structure of the Haflan card hydraulic station includes: motor, oil pump, relief valve (regulating pressure), directional valve, pressure gauge, oil circuit, and oil tank. When hydraulic compression mechanical compression is applied, high-pressure oil is supplied by the hydraulic station, and the component chamber composed of the oil cylinder and piston is filled with oil. When the pressure is greater than the frictional resistance of the compression plate, the compression plate slowly presses the filter plate. When the compression force reaches the pressure value set by the overflow valve (displayed by the pressure gauge pointer), the filter plate, filter frame (plate frame type) or filter plate (box type) is compressed, and the overflow valve begins to unload. At this time, the motor power is cut off, the compression action is completed, and when it returns, the directional valve changes direction, and the pressure oil enters the rod chamber of the oil cylinder. When the oil pressure can overcome the frictional resistance of the compression plate, the compression plate begins to retreat. When hydraulic compression is automatically maintained, the compression force is controlled by an electric contact pressure gauge. The upper and lower limit pointers of the pressure gauge are set to the values required by the process. When the compression force reaches the upper limit of the pressure gauge, the power supply is cut off and the oil pump stops supplying power. Due to possible internal and external leaks in the oil system, the compression force decreases. When it reaches the lower limit pointer of the pressure gauge, the power supply is turned on and the oil pump starts supplying oil. When the pressure reaches the upper limit, the power supply is cut off and the oil pump stops supplying oil. This cycle is used to ensure the compression force during the process of filtering materials.

Filter mechanism

The filtering mechanism consists of a filter plate, a filter frame, a filter cloth, and a pressing diaphragm. The filter plate is wrapped on both sides by filter cloth. When a pressing diaphragm is required, a set of filter plates consists of a diaphragm plate and a side plate. The substrate of the diaphragm plate is covered with rubber diaphragms on both sides, and the outer edge of the diaphragm is covered with filter cloth. The side plate is a regular filter plate. The material enters each filter chamber through the feeding hole on the thrust plate, and solid particles are trapped in the filter chamber due to their particle size being larger than the aperture of the filter medium (filter cloth). The filtrate flows out from the outlet hole below the filter plate. When the filter cake needs to be squeezed dry, in addition to using a diaphragm to press, compressed air or steam can also be used to pass through the washing port, and the airflow can flush out the moisture in the filter cake to reduce its moisture content.

(1) Filtering method

The ways of filtrate outflow are clear flow filtration and dark flow filtration.

A、 Clear flow filtration: Each filter plate is equipped with a water nozzle on the bottom outlet hole, and the filtrate flows out intuitively from the water nozzle.

B、 Underflow filtration: Each filter plate is equipped with an outlet channel hole below, and the outlet holes of several filter plates are connected to form an outlet channel

Dao is discharged through the pipeline connected to the outlet hole below the thrust plate.

(2) Washing method

When the filter cake needs to be washed, there are open flow unidirectional washing and bidirectional washing, and dark flow unidirectional washing and bidirectional washing.

A、 Clear flow unidirectional washing is a process in which the washing liquid enters through the washing liquid inlet holes of the thrust plate, passes through the filter cloth, and then through the filter cake, and flows out from the non porous filter plate. At this time, the outlet water nozzle of the perforated plate is in the closed state, and the outlet water nozzle of the non perforated plate is in the open state.

B、 Clear flow bidirectional washing is a process in which the washing solution is washed twice from the two sides of the washing solution inlet holes above the thrust plate, that is, the washing solution is washed from one side first and then from the other side. The outlet of the washing solution is diagonal to the inlet, so it is also called bidirectional cross washing.

C、 Underflow unidirectional flow washing is a process where the washing solution enters the perforated plate through the washing solution inlet holes of the thrust plate, passes through the filter cloth, and then passes through the filter cake before flowing out from the non perforated filter plate.

D、 Undercurrent bidirectional washing is a process where the washing solution is washed twice from the two washing solution inlet holes on both sides above the stopper plate. The washing solution is washed from one side first and then from the other side. The outlet of the washing solution is in a diagonal direction, hence it is also known as undercurrent bidirectional cross washing.

(3) Filter cloth: Filter cloth is a primary filtering medium, and its selection and use play a decisive role in the filtration effect. When selecting, the appropriate filter cloth material and aperture should be chosen based on factors such as the pH value and solid particle size of the filter material to ensure low filtration costs and high filtration efficiency. When using, the filter cloth should be smooth and not folded, and the aperture should be unobstructed.

classification

plate and frame filter press

1: A plate and frame filter press (plate and frame filter press) consists of a set of filter chambers composed of alternately arranged filter plates and filter frames. The surface of the filter plate has grooves, and its protruding parts are used to support the filter cloth. There are through holes on the corners of the filter frame and filter plate, which form a complete channel after assembly, allowing suspension, washing water, and filtrate to be introduced. Both sides of the board and frame are supported by handles on the crossbeam, and are compressed by a clamping device. The filter cloth between the board and the frame serves as a sealing gasket. The suspended hydraulic pressure is pumped into the filter chamber by the feed pump to form filter residue on the filter cloth until the filter chamber is filled. The filtrate passes through the filter cloth and flows along the groove of the filter plate to the corner channel of the plate frame, and is discharged in a concentrated manner. After filtration, the filter residue can be washed with clean water. After washing, sometimes compressed air is also introduced to remove the remaining washing solution. Then open the filter press to remove the filter residue, clean the filter cloth, re press the plate and frame, and start the next work cycle.

2: The plate and frame filter press is suitable for suspensions with high compressibility or near incompressibility of filter residue. The solid particle concentration of suitable suspension is generally below 10%, and the operating pressure is generally 0.3-0.6 megapascals, with some reaching 3 megapascals or higher. The filtering area can increase or decrease with the number of frames used. The frame is usually square, with an inner edge length of 200-2000 millimeters, a frame thickness of 16-80 millimeters, and a filtering area of 0.5-1200 square meters. The board and frame are tightened using manual screws, electric screws, and hydraulic methods. The board and frame are made of materials such as wood, cast iron, cast steel, stainless steel, polypropylene, and rubber.

chamber pressure filter

The structure and working principle of a box filter press are similar to those of a plate and frame filter press, with the difference being that the two sides of the filter plate are concave, and every two filter plates are combined to form a box shaped filter chamber, eliminating the need for a filter frame. There is a circular hole in the center of the filter plate through which the suspension flows into each filter chamber. This filter is suitable for suspensions that require filtration at higher pressures without washing the filter residue.

Vertical filter press

The vertical filter press filter plate is horizontally and vertically stacked to form a set of filter chambers, occupying a relatively small area. It adopts a continuous filter belt, and after completing the filtration, the filter belt is moved for slag unloading and cleaning, and the operation is automated. The filter press has a wide range of applications and a relatively simple structure. The compression and opening of the plate and frame, as well as the unloading and cleaning of the filter cloth, can all be automated, which is conducive to the development of large-scale filter presses. After adding an elastic rubber diaphragm to the filter chamber of the filter press, high-pressure water or compressed air can be used to compress the filter residue with the help of the rubber diaphragm at the end of the filtration, so that the filter residue can be further pressed and dewatered, forming a variable volume filter chamber and compressed filter residue with a pressure of 1-2 megapascals.

belt filter press

Belt filter press is widely used for sludge dewatering in urban sewage treatment, chemical industry, refining, metallurgy, papermaking, leather making, food, coal washing, printing and dyeing industries. The machine operates continuously, with high automation, energy saving, high efficiency, and easy maintenance, making it an ideal equipment for sludge dewatering.

structural characteristics
1. Adopting advanced Australian technology, the appearance is beautiful and elegant.
2. High structural stiffness, smooth operation, and low noise.
3. Equipped with advanced concentration pretreatment equipment, it has good coagulation effect on sludge and low operating cost.
4. The gravity dehydration zone is equipped with advanced fabric distributors to ensure uniform material distribution and extend the lifespan of the filter belt.
5. It has an ultra long gravity dehydration zone and a wedge-shaped dehydration zone, ensuring sufficient material dehydration and preventing material overflow in the pressing zone.
6. The roller system is arranged in a scientific and orderly manner, with gravity dewatering, wedge dewatering, and press dewatering being discharged separately without interfering with each other. The press dewatering roller has a large diameter ratio, resulting in good dewatering effect. Therefore, it has a large production capacity and is energy-saving and efficient.
7. The continuous operation from feeding to discharging mud cakes has a high degree of automation, and PLC interfaces can be set up as needed for centralized control by microcomputers.
8. The power transmission mechanism adopts mechanical or variable frequency stepless speed regulation, with a large speed range and wide adaptability.
9. The filter belt is equipped with a reliable backwash device to ensure the dehydration effect of the filter belt.
10. Adopting pneumatic tensioning and pneumatic automatic correction device to ensure the safe and normal operation of the filter belt.
11. Safe and reliable operation, equipped with infrared safety protection and comprehensive emergency safety parking device.
12. Filter belts with different structures can be configured according to different materials, resulting in high filtration accuracy.

working principle

The hydraulic compression mechanism of the filter press consists of a hydraulic station, an oil cylinder, a piston, a piston rod, and a Havlan card hydraulic station connected to the compression plate. The structure of the Havlan card hydraulic station includes a motor, an oil pump, an overflow valve (regulating pressure), a directional valve, a pressure gauge, an oil circuit, and an oil tank.

Filtration method: The filtrate flows out through clear flow filtration and dark flow filtration. Clear flow filtration, with a water nozzle installed on the bottom outlet of each filter plate, allowing the filtrate to flow out intuitively from the water nozzle. Underflow filtration, each filter plate is equipped with an outlet channel hole below, and the outlet holes of several filter plates are connected to form an outlet channel, which is discharged through a pipeline connected to the outlet holes below the thrust plate.

Washing method: When the filter cake needs to be washed, sometimes there are unidirectional and bidirectional washing, and unidirectional and bidirectional washing with dark flow.

Dehydration application

1: As a mature dewatering equipment, filter press is widely used in the field of environmental protection and has become an important equipment for sewage and sludge treatment.

2: Mechanical dewatering of sludge mainly removes capillary water between sludge particles. The moisture content of sludge after ordinary mechanical dewatering is usually 65% -80%, and it is in the form of a sludge cake.

3: Mechanical dewatering equipment used to mainly include belt filter presses, plate and frame filter presses, and horizontal screw settling centrifuges. Nowadays, box filter presses, vertical hydraulic filter presses, diaphragm presses, and high-pressure plate and frame presses are commonly used.

4: When using sludge landfill, sludge dewatering can greatly reduce the site for sludge accumulation and save costs incurred during transportation; When composting sludge, sludge dewatering can ensure smooth composting (usually requiring sludge to have a low moisture content during the composting process); If sludge incineration and centralized treatment are carried out, the sludge dewatering rate can be greatly reduced, greatly reducing heat consumption and lowering the cost of hazardous material treatment.

5: However, the complex composition, low relative density, fine particles, and often colloidal state of sludge determine its difficulty in dewatering. Therefore, so far, except for ultra-high pressure vertical hydraulic filter presses, all other filter presses have added drying processes to reduce residual oil (liquid) rates.

6: Belt filter press has low power consumption. Plastic plate and frame filter press has low moisture content in the filter cake, but the horizontal screw settling centrifuge has strong adaptability to sludge flow fluctuations, good sealing performance, large processing capacity, and small footprint. In the past, most sewage treatment plants in our country used centrifuges, belt filter presses, and plate and frame filter presses. Small sewage treatment plants generally used concentration and dehydration integrated machines. The commonly used box type filter press, diaphragm filter press, and ultra-high pressure vertical hydraulic filter press have unique technologies and are ideal equipment for sludge dewatering.

Belt filter press:

1: Continuous operation, the belt press dewatering machine has three 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 scope is expanding. The dewatering effect of belt filter press relies heavily on chemical agents, resulting in high sludge treatment costs.

Plate and frame filter press:

1: Intermittent pressure filtration equipment, used for solid-liquid separation of various suspensions.

2-box filter press: developed after the 1960s. Its characteristic is high filtration pressure, with a maximum pressure of 4.5 MPa; The single machine filtration area is large. There are already 2050 square meters of products available abroad, and the largest filtration area in China has reached 2000 square meters. The liquid content of the filter cake is low, and the moisture content of the pressed filter cake can be further reduced by 5% to 15%; Good corrosion resistance, the filter plate can be made of various reinforced plastics, light weight, good elasticity, corrosion resistance, and wide adaptability; Low operating costs, capable of achieving multiple continuous operations and online control. Modern filter presses are mainly of the box type.

Diaphragm filter press:

1: Intermittent pressure filtration equipment, used for solid-liquid separation of various suspensions. The filter press is equipped with a rubber press diaphragm to dehydrate the filter cake. The medium for expanding the diaphragm can be compressed air (used below 0.7 MPa) or water (used above 0.7 MPa).

2: Ultra high pressure vertical hydraulic filter press: With a unique filter chamber structure, the sludge is subjected to secondary pressing, and the moisture content of the pressed sludge is ≤ 50%; The residual oil rate of pressed edible oil is low, and the technology is leading in China. Currently, it is preferred by many manufacturers for application.

Sludge conditioning:

Generally, domestic sludge is mechanically dehydrated by adding high molecular weight polymers and undergoes "conditioning" treatment. There are various methods of conditioning, including thermophysical methods such as "thermal hydrolysis", "hydrothermal drying", "wet oxidation", etc., physical methods such as ultrasound, microwave, etc., and most commonly chemical methods. By adding certain inorganic chemical salts (agents), the polarity of sludge molecular charges can be changed, particle pores can be increased, and pressure filtration characteristics can be improved. Currently, it is the most common and prevalent in the market The cheap technology is a combination of "sludge chemical conditioning+filter press treatment".

industry standard

1: CJ/T 80-1999 Belt filter press for sludge dewatering

2: JB/T 3966-2001 Coal Chamber Filter Press

3: HG/T 21615-1997 Modified Polypropylene Box and Plate Frame Filter Press

4: JB/T 9040-1999 Belt Filter Press

5: ZB D 96013-1990 YD belt filter press

ZB J 77001-1988 Technical Conditions for Plate and Frame Filter Press

SHS 09015-2004 Maintenance and Inspection Regulations for Belt Filter Press

installation and debugging

1. The filter press should be installed on a flat concrete foundation. The foot of the thrust plate machine at the feeding end is fixed to the foundation with anchor bolts; The bracket end does not require anchor bolts, or the anchor bolts can be locked with two nuts after positioning, leaving a suitable gap between the nut washer and the machine foot base. This machine foot can be slightly extended and retracted. Before positioning, the installation personnel should calibrate the perpendicularity between the crossbeam and the large plane of the thrust plate.

2. The foundation structure should be designed by construction personnel according to the equipment load situation, and it is advisable to grout the anchor bolts twice with reserved holes.

3. There should be sufficient space for operation and maintenance around the filter press. The hydraulic compression filter press should be placed in an appropriate position to ensure that the hydraulic station can work normally.

4. Place the filter plate according to the job requirements, and arrange the feeding, washing, and drainage pipelines. Equipped with a filter pressure display gauge and a return channel for controlling the filter pressure. If it is a diaphragm squeezing type, arrange compressed air pipelines.

5. Hydraulic filter press, inject clean 20 # -40 # hydraulic mechanical oil into the hydraulic station oil tank, with a usage temperature of>-5 ℃; If the ambient temperature is low, hydraulic oil with similar viscosity and low pour point can be used. Hydraulic oil must be added through an 80-100 mesh filter.

6. The mechanical or hydraulic clamping device should work correctly when the power is turned on to start the motor. When hydraulic pressure is applied, the pressure gauge should rise steadily, and there should be no leakage in the hydraulic system. Adjust the working pressure of the hydraulic station correctly according to the size of the model. If insufficient oil is found in the oil tank after testing, it should be replenished.

Fault Analysis

Root cause analysis

(1) Impact phenomenon: During the use of the filter press, there may be a sudden increase in liquid pressure, resulting in a pressure peak that is much higher than the normal pressure. The pressure pointer exceeds the upper limit of the electric contact pressure gauge, which was originally thought to be a pressure gauge phenomenon. After multiple tracking, it was found that this occurred during the pressure holding state, with a pressure value between 4 and 6 MPa higher than the maximum pressure, much higher than the maximum pressure.

Maintenance matters

l、 The filter press must be debugged normally before feeding work, and a comprehensive inspection of the entire machine must be conducted before each shift. Mechanical compression transmission components and gearboxes must be adequately lubricated; Hydraulic compression recheck the oil storage capacity of the oil tank and the working pressure of the hydraulic station. Hydraulic oil is generally replaced once a year, and the hydraulic system should be thoroughly cleaned during replacement. The working pressure of the hydraulic station should be lower than the maximum working pressure of the oil cylinder, but the minimum should not be lower than the allowable filtering pressure. If it is too small, it will cause significant leakage, and if it is too large, it will damage the components.

2. It is prohibited to start working in the factory when the number of filter plates is less than the specified quantity, in order to avoid damaging the components. Before adding materials, check the arrangement of the filter plates. The filter cloth should not be folded to prevent significant leakage; After unloading the cake, the filter plate must be tightly pressed and arranged neatly.

3. Only when everything is normal can the filter plate be compressed and pressurized for filtration. The filtration pressure and temperature must be within the specified range. If the filtration pressure is too high, it will cause leakage, and if the filtration temperature is too high, the plastic filter plate is prone to deformation. When adding materials, the suspension concentration should be uniform. No mixed substances are allowed; After unloading the cake, the filter cloth and filter plate must be washed clean, and residue is not allowed to stick to the sealing surface or feeding channel, otherwise it will affect the smooth feeding and the sealing of the filter plate, resulting in uneven pressure on both sides of the filter plate and deformation and damage of the filter plate.

4. The selection of filter cloth must meet the filtration technology requirements of the filter blade. Before making a new filter cloth, it should be shrunk first, and the opening diameter should be smaller than the filter plate aperture. When matching the filter plate, the cloth holes should be concentric with the plate holes, and the feeding hole cloth should be tightly attached to the cylinder wall. Otherwise, it will cause unclear filtration, low filtration rate, broken cloth cylinder, and fail to achieve the expected filtration purpose.

5. In the initial stage of filter pressing, the filter is relatively turbid. When a layer of filter cake is formed on the filter cloth, the filtrate will become clear. If the filtrate remains cloudy or mixed, it may be due to damage to the filter cloth or deviation between the cloth holes and the plate holes. At this time, the valve should be closed or the feeding should be stopped to replace the filter cloth. A small amount of leakage caused by capillary phenomenon of filter cloth is allowed between filter plates.

6. When moving the filter plate, the force should be even and appropriate, and collision or falling should be avoided to avoid damaging the sealing surface and filter wrench handle. After using the filter cloth for a period of time, it will become hard and its performance will decrease. Therefore, regular inspections are needed. If any changes are found that affect the filtration rate, corresponding low concentration weak acid and weak alkali can be used for neutralization and cleaning to restore the function of the filter cloth. If it cannot be restored, it should be replaced in a timely manner.

7. Slurry, washing solution or compressed air valves must be activated according to the operating procedures and cannot be activated simultaneously. The compressed air pressure during diaphragm squeezing cannot exceed the filtration pressure.