#filter plate

What are the ways to wash the filter plate of the filter press?

1) Open flow non-washable: This form has only one intermediate feed channel. The material enters each filter chamber from the feed hole on the thrust plate through the feed channel, and the filtrate is discharged from the outlet hole of each filter plate through the filter medium. It is suitable for general filtration and has the advantages of fast filtration speed and intuitive filtration effect. 2) Undercurrent non-washable: In addition to the feed channel, this type of filter press also has an outlet channel. The filtrate of each filter plate is discharged together through this channel. This form is suitable for materials that are polluted, toxic, volatile, and do not require washing. 3) Open flow washable: In addition to the feed channel, this form also has a washing liquid inlet channel. Its filtration part is the same as the open flow non-washable. After the filtration is completed, the washing operation is performed. 4) Undercurrent washable: It is divided into undercurrent unidirectional washing and undercurrent bidirectional cross washing. The feed and washing liquid of this type of filter press are the same as those of open flow washable, but the liquid discharge method is different. The liquid of each filter plate is collected and discharged together through the liquid discharge channel. This form is suitable for materials that are polluted, toxic, volatile, and need to be washed.

How to choose filter cloth for filter press?

The selection of filter cloth is very important and plays a key role in the filtering process. The performance of the filter cloth directly affects the filtering effect. In order to achieve a relatively ideal filtering effect and speed, it is necessary to select according to the particle size, density, viscosity, chemical composition and filtering process conditions of the material. The user determines it according to the actual filtering requirements. When cutting the filter cloth, the hole spacing and aperture size must be accurate, and the aperture cannot be too small, otherwise it will block the feed hole; the nylon buckles on the filter cloth must be arranged evenly, and the filter cloth must be cut with special tools such as electric soldering iron to prevent the filter cloth from being off the line.

What items are included in the complete machine inspection of the filter press?

1) Clean the hydraulic station and electric control cabinet, check whether the oil pipes of the hydraulic station are installed correctly, whether the wiring of the electric control cabinet is correct, and whether all electrical wiring is correct.

2) Clean the frame and filter plate, check whether the filter plate is arranged neatly and correctly; check whether the filter cloth is installed with folds, if so, it needs to be flattened.

3) Check whether the configuration of the feed, water washing, blowing and other pipelines and valves is correct and reasonable.

What are the safety-related matters of the filter press?

1) Check the working conditions of various instruments frequently, and repair or replace them in time if any abnormality is found.

2) Operate in strict accordance with the relevant contents of precautions, daily care and maintenance, and filter press fault repair methods, and prohibit various instruments from filtering under abnormal conditions.

3) The working pressure of the oil cylinder is generally around 25Mpa, and the maximum test pressure is 31.5Mpa, but it is strictly forbidden to work for a long time when it exceeds 28Mpa, and it is absolutely forbidden to work when it exceeds 31.5Mpa.

What are the preparations before the filter press test?

1) Sufficient filter slurry, air source, water source, etc. should be prepared to meet the test conditions.

2) For users who need to test and inspect the filter slurry, professional test personnel and the required test equipment and reagents should be equipped.

3) Equipped with 1-2 maintenance workers and several operators.

4) General tools such as small jack, adjustable spanner, hammer, wire cutters, screwdriver, pipe clamp, hexagonal wrench, etc. are available, as well as a small amount of auxiliary materials such as engine oil, lubricating oil, cotton yarn, etc.

Understanding Filter Press Fundamentals

● What is a Filter Press?

A filter press is an industrial equipment used for the separation of liquids and solids. It operates by applying pressure to the mixture, forcing the liquid through the filter media while retaining the solids. This process is essential in various industries like chemical manufacturing, food and beverage processing, pharmaceuticals, and wastewater treatment. The filter press is composed of a series of filter plates and frames, a hydraulic or manual closing system, and piping for the feed and discharge of liquids.

● Primary Uses and Applications

Filter presses are invaluable in processes where the separation of liquid from solids is necessary to achieve a product of higher purity or to recover valuable materials from industrial waste. Common applications include dewatering sludge in wastewater treatment plants, filtering wine and beer, and extracting essential oils in the pharmaceutical industry. They are also widely used in mining operations for the recovery of precious metals and minerals from ore slurry.

● Basic Components and Operation

The primary components of a filter press include the filter plates, filter cloth, hydraulic or manual closing mechanism, and the feed pump. The plates are designed to hold the filter cloth in place, which captures the solid particles while allowing the liquid to pass through. The closing mechanism ensures a tight seal during operation to prevent leakage. The feed pump supplies the slurry to the press under pressure, facilitating the separation process.

Determining Your Filtration Needs

● Assessing Your Process Requirements

Before choosing a filter press, it’s crucial to assess the specific requirements of your filtration process. Consider factors such as the type and volume of material to be filtered, the desired purity level of the filtrate, and the acceptable moisture content of the filter cake. Understanding these parameters will help you select a filter press that meets your operational needs efficiently.

● Identifying the Type of Materials to Filter

The nature of the material to be filtered greatly influences the choice of filter press. Different materials have varying filtration characteristics, such as particle size, viscosity, and chemical compatibility. For example, filtering a chemical slurry requires materials that can withstand corrosive substances, while filtering food products necessitates FDA-approved materials to ensure safety and compliance.

● Volume and Frequency of Filtration

The volume and frequency of your filtration operations will also dictate the size and type of filter press required. High-volume operations may necessitate a larger filter press or multiple units to handle the throughput efficiently. Conversely, lower-volume and less frequent operations might be adequately served by a smaller, more economical unit.

Choosing the Right Plate Size

● Importance of Cubic Foot Capacity

The cubic foot capacity of a filter press is a critical factor in determining the appropriate plate size. This capacity refers to the volume of solids the press can hold in a single cycle. Selecting the right plate size ensures that the filter press can handle the required volume of slurry without frequent cycling, thereby optimizing efficiency and workflow.

● Common Plate Sizes (470 mm, 630 mm, 800 mm)

Filter plates come in various sizes, with 470 mm, 630 mm, and 800 mm being common options. The choice of plate size is influenced by the desired filtration capacity and the available space in your facility. Larger plates can hold more solids, reducing the number of cycles needed, which can be advantageous for high-volume operations.

● Considerations for Expandability

When selecting a plate size, consider the potential for future expansion of your operations. Choosing a filter press that can accommodate additional plates in the future allows for scalability, accommodating increased production needs without requiring an entirely new system. This flexibility can be a cost-effective strategy for growing businesses.

Selecting Plate Material

● Differences in Material Types (Polypropylene, Stainless Steel)

The material composition of filter plates affects their durability, chemical resistance, and suitability for different applications. Polypropylene is a common choice due to its chemical resistance and lightweight properties, making it ideal for many industrial applications. Stainless steel plates offer superior strength and corrosion resistance, suitable for filtering aggressive chemicals or high-temperature processes.

● Food Grade vs. Industrial Grade Materials

For applications in the food and beverage industry, using food-grade materials is essential to ensure compliance with health and safety regulations. Food-grade polypropylene or stainless steel is typically used to prevent contamination and ensure the integrity of the filtered product. In industrial settings, standard industrial-grade materials may suffice, provided they meet the required chemical and thermal resistance standards.

● High Temperature and Special Materials

Certain applications may involve high temperatures or particularly aggressive chemicals, necessitating the use of specialized materials. High-temperature polypropylene or glass-filled polypropylene can withstand elevated temperatures, while materials like Kynar (PVDF) offer excellent resistance to a wide range of chemicals. Selecting the appropriate material ensures the longevity and reliability of the filter press under specific operating conditions.

Identifying Plate Style Options

● Recessed Gasketed Plates vs. Non-Gasketed Plates

Filter plates are available in recessed gasketed and non-gasketed styles, each with its advantages. Recessed gasketed plates provide a secure seal, minimizing the risk of leakage and ensuring a more efficient filtration process. Non-gasketed plates, on the other hand, are easier and quicker to change out, reducing downtime during maintenance but may allow some seepage during operation.

● Membrane Squeeze Plates for Higher Efficiency

Membrane squeeze plates are a specialized type of filter plate that can expand and contract to further dewater the filter cake after the initial filtration cycle. This squeezing action results in a drier cake and higher overall efficiency, reducing disposal costs and maximizing yield. Incorporating membrane squeeze plates can be particularly beneficial in processes where minimizing moisture content is critical.

● Seals and Gasket Choices (EPDM, Viton)

The type of seals and gaskets used in filter plates significantly impacts their performance and compatibility with different substances. EPDM (ethylene propylene diene monomer) seals are commonly used due to their flexibility and resistance to a wide range of chemicals. Viton (fluoroelastomer) seals offer superior chemical resistance and are suitable for applications involving highly aggressive substances. Selecting the appropriate seal material ensures a leak-free operation and long service life.

Considering Plate and Press Pressure Ratings

● Standard 100 psi Design

Most filter presses are designed for standard operating pressures of around 100 psi, which is sufficient for many dewatering applications. At this pressure, the filter press effectively separates solids from liquids, producing a filter cake with approximately 30-35% solids content. This design is suitable for a wide range of industrial processes.

● Benefits of Higher Pressure Designs (225 psi)

For applications requiring higher efficiency and drier filter cakes, higher pressure designs, such as 225 psi, are available. Operating at increased pressures can improve yield per cycle and produce filter cakes with higher solids content, potentially up to 50% or more. This enhancement is particularly useful in processes where the disposal or handling of wet filter cake is challenging.

● Impact on Cake Solids and Yield

The choice of pressure rating directly affects the solids content and yield of the filter cake. Higher pressure designs not only reduce the moisture content of the cake but also increase the throughput of the filter press by shortening cycle times. Understanding the specific requirements of your process will guide you in selecting the appropriate pressure rating for optimal performance.

Choosing Cake Thickness

● Standard vs. Optional Cake Thicknesses (32 mm, 25 mm, 38 mm, 50 mm)

The thickness of the filter cake is another important consideration. The standard cake thickness is typically 32 mm, but options for thicker or thinner cakes are available, such as 25 mm, 38 mm, and 50 mm. Thicker cakes may be advantageous for easily filtered materials, while thinner cakes are more suitable for high-viscosity or slimy substances.

● Impact on Filtration Efficiency and Material Type

The thickness of the filter cake affects the overall filtration efficiency and the ease with which the material is processed. Thinner cakes allow for faster filtration of high-viscosity liquids, reducing cycle times and increasing throughput. Thicker cakes, conversely, can enhance the retention of finer particles, making them ideal for materials that require more thorough separation.

Selecting the Right Filter Cloth

● Material Types and Weave Styles

Filter cloths play a crucial role in the filtration process, impacting both the clarity of the filtrate and the quality of the filter cake. They are available in various materials, including polypropylene, polyester, and nylon, each offering different properties suitable for specific applications. The weave style of the cloth, such as plain weave, twill weave, or sateen weave, also affects its performance characteristics, including particle retention, flow rate, and resistance to blinding.

● Importance of Air Permeability Values

Air permeability is a critical parameter in selecting the right filter cloth, as it determines the cloth's ability to allow air or liquid to pass through while retaining solids. Lower air permeability values are suitable for applications requiring high particle retention and clear filtrate, while higher values are better for processes needing rapid filtration and high flow rates. Matching the air permeability to your specific needs ensures optimal filtration performance.

● Cloth Testing and Selection Process

To select the most suitable filter cloth, conducting filterability tests with samples of the process liquid is highly recommended. These tests help determine the best material, weave style, and air permeability value for your specific application. If testing is not feasible, standard monofilament x multifilament filter cloths with known performance characteristics can be used as a starting point, with adjustments made based on actual operational results.

Automation vs. Manual Operation

● Manual and Semi-Automatic Operation Details

Filter presses can be operated manually, semi-automatically, or fully automatically, depending on the level of automation desired. Manual and semi-automatic systems require operator intervention to start and manage the filtration process, including opening and closing the press, shifting plates, and initiating the blow-down cycle. These systems are generally more cost-effective and suitable for smaller operations or processes with lower throughput.

● Benefits of Fully Automated Systems

Fully automated filter presses offer significant advantages in terms of efficiency, consistency, and labor savings. Once the initial setup is complete, these systems can perform all necessary operations, including filling, pressing, blow-down, plate shifting, cake discharge, and cloth washing, with minimal operator input. This automation improves cycle times, reduces downtime, and enhances overall productivity, particularly in high-volume and continuous operations.

● Factors Influencing the Choice

The decision between manual, semi-automatic, and fully automated filter presses depends on several factors, including the volume of material to be processed, the available budget, and the desired level of operational efficiency. Smaller businesses or those with intermittent filtration needs may opt for manual or semi-automatic systems to save on initial investment costs. In contrast, larger operations or those requiring consistent, high-throughput processing will benefit from the increased efficiency and reduced labor costs of fully automated systems.

Additional Features and Accessories

● Optional Back Plates for Shorter Cycles

For applications where shorter cycle times are desired, optional back plates or blank plates can be used to temporarily reduce the capacity of the filter press. By moving the follower plate forward in the plate stack and placing the blank plate behind it, the press can operate with fewer plates, reducing the volume of slurry processed per cycle and consequently shortening the cycle time. This feature provides flexibility for operations with varying processing needs.

● Discharge/Air Blow-Down Piping Options

The discharge and air blow-down piping is available in both manual and automatic configurations. Manual systems require operator intervention to initiate the blow-down process, while automatic systems can perform this task without human input. Additionally, materials such as schedule 80 CPVC or schedule 40 stainless steel can be chosen based on the specific requirements of the application, ensuring durability and compatibility with the process fluids.

● Feed Styles and Core Blow-Down Availability

The feed style of a filter press can vary depending on the application, with center feed being standard for most processes. Corner feed options are also available for specific needs, such as enhanced distribution of slurry across the filter plates. An optional core blow-down feature is available to purge the center feed line of residual fluid, further improving the efficiency and cleanliness of the filtration process.

Conclusion

Choosing the right filter press for your operation involves careful consideration of various factors, including the type and volume of materials to be filtered, the desired level of automation, and the specific requirements of your process. By understanding the fundamental principles of filter press operation and evaluating the available options for plate size, material, style, pressure rating, cake thickness, and filter cloth, you can make an informed decision that maximizes efficiency and productivity.

During use, do you spray grout between the filter plates?

If spraying suddenly occurs after long-term use, it may be caused by insufficient pressure in the machine itself or uneven filter cloth. If this happens, the equipment should be shut down immediately and check whether the filter cloth is flat, has debris or is damaged. Debris should be cleaned up in time, and if the filter cloth is damaged, replace it in time. If there is no problem with the filter cloth, the hydraulic system needs to be checked. If the oil level is insufficient, replenish the hydraulic oil. If the relief valve is damaged, repair or replace it. If the oil pump is damaged, replace the oil pump.

The filter plate cannot be opened, what should I do?

After the filter press is blown and released, the filter plate often cannot be opened or stops working intermittently. Then, you can try the following solutions: ① The filter plate must be loosened to relieve pressure to meet the pressure standard. Once the pressure is not completely released, the filter plate will become loose due to the operating lock. ② If the system loses too much during long-term operation and the hydraulic oil cannot be replenished in time, there will be insufficient oil supply in the system, which will lead to poor continuity of the hydraulic cylinder and intermittently stop working.

During the closing process, the action of the filter plate is out of sync?

When the filter press is working, there is a linkage and locking relationship between the internal mechanical structures. Once the filter plate movement is out of sync after the closing operation, you should promptly check whether the unloading trolley is in the initial position. If the initial position of the unloading trolley does not change, the initial position should be further checked to see if the detection device is operating normally. If there is a problem with the detection device, it should be repaired in time.

What should I do if the filter plate is damaged?

Damage to the filter plate may be caused by the following reasons:

The feed hole is blocked; the feed pressure is too high; the material concentration is high and the fluidity is too poor; the feed temperature is too high; the filter cloth is damaged and the liquid outlet hole is blocked.

The corresponding treatment methods are as follows: if several filter plates near the feed port are damaged, it can be initially judged that the feed port is clogged, the slurry concentration is too high, or the feed hole is not cleaned in time, which can cause the filtrate to be diluted; back pressure occurs Or the pressure gauge shows a pressure exceeding the pressure specified on the nameplate, indicating that the feed pressure is high. The pressure controller system at the feed end should be adjusted in time; the material concentration should be appropriately reduced to improve the material fluidity; first understand the temperature of the material. When the temperature of the filtered material exceeds the required When setting the operating temperature of the filter plate, explain the reason to the customer, and replace the appropriate filter plate or adopt a temperature to cool the slurry before filtering; if the filtrate of a few faucets is turbid, it can be judged that the filter cloth is damaged and the faucet is not working. If the liquid is flowing, it can be judged that the liquid outlet hole is clogged. The filter cloth should be replaced and the liquid outlet hole should be cleaned to ensure that the filtrate flows out normally and clearly.

How to identify the quality of filter plates?

First of all, the necessary condition for the filter plate is that the size of the filter plate is basically the same as that of the original equipment, including the length, width and thickness of the filter plate. If there is a deviation, the filter plate will move left and right during filtration, and may even fail to fit, seriously affecting the pressure. The overall operation of the filter.

Secondly, there are holes inside the filter plate. Since the current filter plate is made of thermally processed polypropylene, the filter plate is prone to holes during the casting process. When the holes reach a certain number, the filter plate is not a qualified product. .

Then there is the depth of the depression of the filter plate. The depth of the depression of the filter plate determines the workload of each gap cycle of the equipment. Generally, the deeper the depth of the filter plate, the greater the workload each time, but the deeper is not the better. When the filter plate is depressed, When the depth exceeds the bearing capacity of the filter plate itself, the filter plate is easily broken or damaged, and may even cause the filter plate to burst suddenly, which is life-threatening.

What is the reason for the low closing pressure of the filter plate?

The operating status of the fiber rotary disc filter includes: filtration, backwashing, and mud discharge status. (1）Filtration: outside in and inside out, the sewage gravity flows into the filter body, so that the filter disc is completely immersed in the sewage. At the same time, in order to distribute water evenly everywhere and produce low disturbance in the water inflow, a water distribution weir must be installed in the filter. The sewage is filtered through the filter cloth, and the filtrate is collected through the hollow tube and then flows into the outlet tank and weir to discharge the filter. Filtration is continuous during the entire operation, even during the cleaning process, filtration is still taking place.

(2) Cleaning: During filtration, part of the sludge is adsorbed in the fiber wool filter cloth and gradually becomes a sludge layer. As sludge accumulates on the filter cloth, the filtration resistance of the filter cloth increases, and the water level in the filter gradually rises. The liquid level change in the filter tank is monitored through a liquid level sensor installed in the filter tank. When the liquid level in the tank reaches the cleaning set value (high water level), the control panel starts the backwash pump and starts the filter disk rotation to start the cleaning process. . Backwash time and cycle can be adjusted. The sludge on the filter cloth passes through the back-suction device, is discharged through the backwash pump, and enters the plant sludge system.

During filtration, the filter plate is in a stationary state, which is conducive to the deposition of sludge. During cleaning, the filter turntable rotates at a speed of 0.5-1r/min. The backwash water pump suctions the surface of the filter cloth with negative pressure to remove the sludge particles accumulated on the filter cloth. The water in the filter turntable is simultaneously sucked from the inside out. and clean the filter cloth. The instantaneous flushing area only accounts for about 1% of the total filter turntable area, and the backwashing process is intermittent.

During normal cleaning, 2 filter turntables form a group, and one set of filter disks is cleaned each time. Controlled by the electric valve on the suction pump pipeline that automatically switches, the cleaning of each group is performed alternately during a complete cleaning process of the fiber turntable filter. During this period, the work of the suction pump is a continuous process.

(3)Sludge discharge: There is a bucket-shaped bottom under the fiber turntable microfilter turntable, which is conducive to the collection of sludge at the bottom of the tank. The sludge deposition at the bottom of the pool reduces the amount of sludge on the filter cloth, which can extend the filtration time and reduce the amount of backwash water. After a set period of time, the control panel starts the sludge discharge pump and discharges the sludge to the factory sludge system through the perforated sludge discharge pipe, valve and pump at the bottom of the pool. Among them, the mud discharge interval and mud discharge duration can be adjusted.

Our company supports technical guidance, so you don’t have to worry about the filter machine operation and maintenance, The customers we have served come from different industries, mainly for semiconductor WWT, WWT, iron ore filtration, clay filtration, red mud filtration, chemical filtration, carrageenan Filtration, palm oil filtration, coconut oil filtration, dye filtration, food industry, pharmaceutical industry and other solid-liquid separation applications.