Common fault plate and frame filter press

Plate and frame filter press is the equipment for sludge treatment in sewage treatment system. Its function is to filter the sludge after sewage treatment to form large filter cake (mud cake) for removal. The plate and frame filter press consists of filter plate, hydraulic system, filter frame, filter plate transmission system and electrical system. The working principle of the plate and frame filter press is relatively simple. First, the plate and frame group is compressed by hydraulic force, and the precipitated sludge enters from the middle and distributes among the filter cloth.

Due to the compression of the plate and frame, the mud can not overflow. Under the high pressure of screw pump and diaphragm pump, the water in the mud oozes from the filter cloth and flows into the return pipe, while the mud cake is left in the cavity. After that, the pressure of the plate and frame is relieved, the filter plate is pulled open, and the mud cake falls by gravity and is pulled away by the car. Therefore, the filter pressing process is the last process in the sewage treatment process.

Damage to the plate itself. The causes of plate damage are as follows:

1.When the sludge is too thick or the dry block is left behind, the feeding port will be blocked. At this time, there is no medium between the filter plates, and only the pressure of the hydraulic system itself is left. At this time, the plate itself is easily damaged due to long-time pressure.

2.When the material is insufficient or contains inappropriate solid particles, the plate and frame itself will be damaged due to excessive force.

3.If the outlet is blocked by solid or the feed valve or outlet valve is closed when starting, there is no place for pressure leakage, which will cause damage.

4.When the filter plate is not cleaned up, sometimes the medium will leak out. Once it leaks out, the edge of the plate and frame will be washed out one by one, and a large amount of medium leakage will cause the pressure can not be increased and the mud cake can not be formed.

Corresponding troubleshooting methods:

1.Use nylon cleaning scraper to remove mud from the feed port

2.Complete the cycle and reduce the filter plate volume.

3.Check the filter cloth, clean the drainage outlet, check the outlet, open the corresponding valve and release the pressure.

4. Clean the filter plate carefully and repair the filter plate

The repair technology of filter plate is as follows:

After several years of use, for some reason, the edges and corners of the filter plate are scoured out. Once the furrow marks appear, they will expand rapidly until the formation of filter cake is affected. At first the cake becomes soft, then it becomes semi slimy, and finally the cake cannot be formed. Due to the special material of filter plate, it is difficult to repair, so it can only be replaced, resulting in high cost of spare parts. The specific repair methods are as follows:

Repair steps:

1. Clean the groove, leak out fresh surface, can use small saw blade to clean

2. Black and white two kinds of repair agent according to the ratio of 1:1

3. Apply the prepared repair agent on the groove, and apply a little higher

4. Quickly set up the filter cloth, squeeze the filter plate together, make the repair agent and the filter cloth stick together, and squeeze the groove at the same time

5. After extrusion for a period of time, the viscose naturally takes shape and no longer changes. At this time, it can be used normally.

The main causes of water seepage between plates and frames are as follows:

1. Low hydraulic pressure

2. Fold and hole on filter cloth

3. There are lumps on the sealing surface.

The treatment method of water seepage between plates and frames is relatively simple, as long as the corresponding increase of hydraulic pressure, replacement of filter cloth or use of nylon scraper to remove the block on the sealing surface.

Filter cake is not formed or uneven

There are many reasons for this phenomenon, such as insufficient or uneven cake feeding. In view of these faults, we should carefully investigate the causes, and finally find the exact problem, and then symptomatic treatment to solve the problem. The main solutions are: increasing the feed, adjusting the process, improving the feed, cleaning or replacing the filter cloth, cleaning the blockage, cleaning the feed hole, cleaning the drain hole, cleaning or replacing the filter cloth, increasing the pressure or pump power, starting at low pressure, increasing the pressure, etc.

The filter plate is slow or easy to fall off. Sometimes, due to too much oil and dirt on the guide rod, the filter plate will walk slowly and even fall off. At this time, it is necessary to clean the guide rod in time and apply grease to ensure its lubricity. It should be noted that it is strictly forbidden to apply thin oil on the guide rod, because the thin oil is easy to fall off, which makes the bottom very slippery. It is very easy for personnel to fall down during operation and maintenance here, causing personal injury accidents.

Hydraulic system failure.

The hydraulic system of plate and frame filter press mainly provides pressure. When the oil injection in oil chamber a increases, the piston moves to the left to press the filter plate to make it airtight. When more oil is injected into the oil chamber B, the piston moves to the right and the filter plate is released. Due to the precision manufacturing, hydraulic system failure is less, as long as you pay attention to routine maintenance. Nevertheless, due to wear and tear, oil leakage will occur every year or so. At this time, the O-ring as shown in the figure should be repaired and replaced.

The common hydraulic faults are that the pressure can not be maintained and the hydraulic cylinder is not suitable for propulsion. The main reasons for not maintaining pressure are oil leakage, O-ring wear and abnormal operation of solenoid valve. The common treatment methods are to remove and check the valve, replace the O-ring, clean and check the solenoid valve or replace the solenoid valve. The improper propulsion of hydraulic cylinder is obviously that the air is sealed inside. At this time, as long as the system pumps air, it can be solved quickly.

Post time: Mar-24-2021