In zinc-copper hydrometallurgy, titanium dioxide, kaolin processing and other industries, with the filter press feeding pump shaft seal easily damaged, usually 10 days and a half months to be repaired, and some even only 3 to 5 days It is necessary to repair, so the filter press pump maintenance costs are more than 5 times the conventional pump, which is well-known in the industry, and has been recognized by everyone. Why is the shaft seal of filter press feeding pump easily damaged? According to our many years of observation and analysis, that there are the following main reasons. Sealing damage is due to the sealing part of the cavity caused by the pressure rise, the reason for the pressure increase is the pump forced pressure operation and pump components (impeller, pump housing, etc.) wear two reasons. Pump pressure due to the nature of the pressure filter feed pump working nature of the decision: because there is no pressure you can not filter. The pump component wear and tear is the actual conditions caused by: Because it is the filter press feed, then the material must have solid material, a solid material will pump components wear and tear. The above elements of the synthesis, constitutes a filter press pump shaft seal easily damaged, but also the industry over the years difficult to solve the problem. The industry has to solve this problem has been thought of ways: First, increase the impeller or impeller for the sealed chamber decompression, the consequences are two: First, increase power consumption, no savings; Second, wear and tear still exists, but the seal life slightly There is growth. Second, the commonly used power seal (lip-shaped seal) to mechanical seal, do not know the mechanical working chamber pressure can not be increased, especially in the solid-phase material containing machine seal, once the cavity pressure increases The solid material will be pushed to the friction kettle working surface, thus causing damage to the mechanical seal wear. Therefore, the mechanical seal pressure filter with the pump life will not be long, but the relative dynamic seal slightly better. Third, in the above two methods do not work, frequent replacement of pump components (impeller, pump housing, sealed three) to maintain normal production. Fourth, the new method of discussion. The focus of the new method is how to make the pressure inside the sealed cavity does not increase, the process is: as long as the pressure does not rise, you can keep the seal life. In what way to solve the pressure inside the sealed chamber does not increase the problem? The tried-and-true method is to design the pump suction port at the seal, so that the seal chamber is under a relatively low pressure in the working state, the sealing life can be prolonged. We have tried it on the HFM suction pump and have obvious effect. Conditions conditions, compared with the use of sealed form, seal life can be 2 to 3 times longer.