Common Problems And Solutions During The Operation of Plate And Frame Filter Press

Dewatering machine,In the coal gasification industry, gasification filter press cake is usually mixed with thermal coal for co firing. However, due to the high moisture content of the filter cake, direct co firing can cause coal blockage in thermal coal. In order to reduce the risk of coal blockage caused by co firing of thermal coal, it is necessary to further reduce the moisture content of the filter cake. The plate and frame filtration can effectively reduce the moisture content of the filter cake, so it is necessary to ensure the stable operation of the plate and frame filter press. Based on this, common problems and solutions during the operation of plate frame filter are discussed. Introduction to 1 Common Solid Liquid Separation Equipment: 4 Common Types of Solid Liquid Separation Equipment.

1.1 The vacuum belt filter utilizes the coordinated operation of a rotating motor, reducer, and traction roller to effectively utilize the pressure changes of materials and the maximum vacuum degree they bring, thereby achieving solid-liquid separation. In addition, the filter cloth is installed on the tape to better complete the entire filtration process. By connecting the circular friction belt and water seal, the track can effectively slide between the vacuum chambers. At the same time, by connecting vacuum equipment, a vacuum filtration zone can be constructed on the surface of the track, and a large amount of mud can be smoothly transferred to the filter cloth.

1.2 Disc Vacuum Filter Disc vacuum filter has excellent filtration performance, which can effectively separate mud and other substances, and achieve more efficient filtration effect by changing the vacuum flow rate. In addition, the disc vacuum filter also has a series of the latest technologies, such as adjustable agitator, adjustable exhaust device, and adjustable filter disc guide frame.

1.3 Spiral discharge settling centrifuge Spiral discharge settling centrifuge is used to achieve complete separation from natural fluids through centrifugal precipitation, mainly for solid-phase dehydration. In theory, the spiral discharge settling centrifuge utilizes the principle of density difference between solid and liquid phases to produce a relatively clear liquid phase with a lower solid phase moisture content.

1.4 Plate and frame filter press: Many filter press plates and frames with striped patterns are assembled into a machine after regular display. Plate and frame filter presses ,filter press china usually adopt intermittent operation, and their processing capacity is relatively weak. However, plate and frame filter presses usually have strong filtering driving force, and the produced filter cake is dry and can be recycled.

2. Operation process of plate and frame filter press

2.1 Plate and Frame Filter Press System The plate and frame filter press system includes a slurry tank, a feed pump, a filter press thrust plate filter plate main beam machine, a press water tank, a press water pump, a cloth washing water tank, a cloth washing water pump, a belt conveyor, a compressed air storage tank, an instrument air storage tank, a compression plate machine base, an oil cylinder, an electric control cabinet, a hydraulic station diagram. The plate and frame filter press is composed of multiple parts, including a thrust plate, a main beam, a pressure plate, a manual pull plate system, a machine base, an electric control cabinet, a hydraulic control system, a washing filter cloth equipment, a flipping plate equipment, a filter cloth, a discharge port, a diaphragm pressing and filtrate discharge device, as well as the population and outlet of the slurry, and equipment for connecting the filter cloth and water. Through an efficient mud conveying system, a closed space is established between the two filter plates of the filter press to generate high pressure and effectively isolate the filtrate and filter cake.

2.2 Operation process of plate and frame filter press,filter press factory.

(1) Feed: When the slurry is added to the storage tank, the plate and frame filter press pushes the slurry into the filter chamber composed of multiple filter plates through pressure, ultimately filling the entire filter chamber and forming a thick layer of filter cake.

(2) Filter cake: As the material flows, this layer of filter cake will be squeezed out and finally sent to the vehicle that pulls the filter cake by the belt conveyor. After collection, it will be used for co firing with power coal.

(3) Filtrate: After the slurry is dehydrated by the filter press, the clear liquid is discharged from the filter press and flows automatically to the grinding water tank.

(4) Filter plate group: A group of adjacent and positioned filter plates installed between the compression plate and the thrust plate of the filter press.

(5) Diaphragm squeezing: Inject water into the diaphragm plate to expand the diaphragm chamber, and further discharge the residual filtrate in the filter cake by reducing the volume of the filter chamber.

(6) Flip plate device: In order to prevent the filtrate and filter cloth flushing water from flowing into the filter cake, conveyor track, and receiving vehicle, the flip plate device uses hydraulic cylinder expansion and contraction action to open the flip plate before the filter cake is discharged, and close the flip plate after the filter cake is discharged.

Common faults and solutions in the operation of 3 plate and frame filter presses

filter press manufacturers

Common faults and solutions in the operation of 3 plate and frame filter presses

3.1 Insufficient oil pressure The main causes of insufficient oil pressure are hydraulic pump (see Figure 6) overflow valve failure, oil pump failure, valve block and joint leakage, oil red seal ring aging, valve leakage or low oil level. The solution is to repair or replace the faulty part.

3.2 Low pressure squeezing is mainly manifested by insufficient pressure of the squeezing water pump, which makes it impossible to proceed to the next step of the program. The main causes are cracking of the filter plate pressing water pipe, empty liquid level in the pressing water tank, malfunction of the pressing water pump, and failure to open the instrument valve. The usual handling measures are to replace, repair, or contact instrument personnel to handle the valve.

3.3 Leakage between Filter Plates The causes of material leakage between filter plates are usually due to excessive pressure and flow of the feed pump, resulting in dirt on the sealing surface of the filter plate and diaphragm, uneven and wrinkled filter cloth, and unstable oil pressure. The solution is to readjust the feeding pump and clean the filter cloth, and adjust the oil pressure to a suitable range.

The cause of filter plate breakage is damage to the filter cloth, resulting in incomplete filling of the filter cake, excessive loading rate, blockage of the inlet pipes of the filter plate and diaphragm, and blockage of the exhaust valve. The measures taken include: timely replacement of filter cloth to ensure that the filter cake fills the filter chamber for pressing; Slow down the feeding speed; Clean the holes in the feeding hopper; Keep the inside of the filter plate clean.

The reason for lifting the filter plate upwards is that the installation foundation is not stable or the lower part of the filter plate is not clean. The treatment measure is to re adjust the foundation and remove the slag under the filter plate.

3.6 Unclear filtrate and long feeding time of the plate and frame may be caused by damage to the filter cloth, deviation in the size of the screen mesh, cracks in the joint of the screen mesh, leakage points in the pipeline, and problems with the operation of the feed pump (such as impeller detachment or unopened outlet valve of the feed pump). The handling measures are to inspect and replace the filter cloth, eliminate equipment and pipeline defects or leaks.

3.7 Hydraulic system noise may be caused by air intake, loose fasteners, high hydraulic oil viscosity, clogged return oil filter, etc. The solution is to open the exhaust valve, ensure that the fasteners are secure, and reduce the viscosity of the hydraulic oil.

The failure of the 3.9 filter press to operate is caused by the limit problem of the filter press itself and the failure of the pressing pressure gauge to reach the set minimum value. The solution is to promptly contact the transportation and maintenance personnel for adjustments.

3.10 Filter cloth blockage Over time, the filter cloth of the filter press may become clogged. When the filtration time is significantly shortened, the moisture in the filter cake is significantly reduced, and the instantaneous filtration pressure of the filter press is significantly increased, resulting in a significant acceleration of the liquid discharge time. At this time, it is necessary to clean the filter cloth. Usually, the original filter cloth is removed and cleaned again, but this method is time-consuming and labor-intensive. There are significant drawbacks to traditional cleaning methods, such as lower cleaning pressure, requirement for smooth cleaning surfaces, and lower cleaning efficiency. For this purpose, this system adopts an automatic filter cloth flushing device. Through the flushing mechanism installed on the upper part of the filter press, high-pressure water is diverted to several nozzles. The filter cloth installed on the filter plate is flushed one by one through the programmable system of the flushing device, the lifting device, and the automatic pulling plate system of the filter press.

3.11 Other fault diagnosis

(1) The feeding pump has a long feeding time, insufficient feeding pressure, and serious black water carryover in the discharged filtrate. Possible reasons include damage to the filter cloth and leaks in the pipeline. At this time, the on-site pipelines and filter cloth should be inspected immediately and any defects should be eliminated.

(2) The feed pump can operate, but the liquid level in the slurry storage tank drops slowly and the feed pressure does not rise. Possible reasons include the impeller of the feed pump falling off or the valve outlet not being opened. The solution is to promptly check the operation of the feed pump.

(3) The pressure cannot be relieved during the compression process, which may be due to oil leakage at the pipeline, low hydraulic oil level in the pump station, oil pump failure, damaged one-way valve, damaged oil cylinder seal, etc.

(4) Poor sealing of pipelines and oil cylinders, damage to one-way valves and solenoid ball valves, and possible failure to maintain pressure after compression.

(5) During the compression process, if the pressure gauge is damaged or the external wiring is loose, there may be a situation where the pressure limit is reached but the compression process continues.

(6) If the number of plates is not configured according to the nameplate of the plate and frame filter press during operation, the oil pump may stop before reaching the upper pressure limit.

(7) The pulling plate trolley and chain are stuck by foreign objects, which can cause abnormalities in the pulling plate trolley. In daily work, it is necessary to regularly apply engine oil to the chain and track to ensure good lubrication of the parts.

Conclusion: In summary, mechanical leakage and program errors are more likely to occur during the operation of the plate and frame filter press. Optimizing measures to address these issues can help solve the problem and ensure stable system operation. In the future, it is necessary to optimize the process of the plate and frame filter press itself and improve the technical level of operators to ensure the long life cycle of the plate and frame filter press system.