Industry news

Do you know all the seven seals of chemical pumps?

2021-05-31
The sealing of chemical pump plays an important role in the operation of the whole equipment. The leakage of the sealing system of chemical pump will seriously affect the normal operation of the equipment. At present, the main shaft seal devices used in pumps in China are as follows: packing seal, labyrinth seal, mechanical seal, oil seal, gasket seal, thread seal and power seal. How many do you know?

Oil seal

Pump oil seal is a kind of self tightening lip seal with simple structure, small size, low cost, convenient maintenance and small resistance torque. It can not only prevent medium leakage, but also prevent the invasion of external dust and other harmful substances. Moreover, it has certain compensation ability for wear, but it is not resistant to high pressure, so it is generally used in chemical pumps in low pressure occasions.

Chemical pumps rely on centrifugal principle to extract liquid materials. Chemical pumps made of special materials are suitable for extracting corrosive liquid from bottles, barrels, cylinders, pools or other containers. Due to the existence of corrosion, volatilization, explosion and other dangers of the medium extracted by chemical pumps, the sealing performance requirements of the pump body are much higher than other types of pumps.

The oil seal of chemical pump should be installed on the surface with manufacturing accuracy of h8-h9 and surface roughness of 1.6-0.8 μ M and surface hardened. The sealing medium should not contain solid particles and impurities, otherwise it will cause the rapid wear of oil seal and shaft and make the seal failure.

In the selection of this sealing method, we should fully consider the performance and requirements of the materials transported by the chemical pump, so as to avoid unnecessary leakage and prevent accidents.

The main causes of oil seal leakage are as follows:

The main cause of oil leakage is that the oil seal is not tight. When the shaft is worn to form a groove, even if the new oil seal is replaced, it can not be sealed, because the contact pressure between the oil seal lip and the shaft is reduced, resulting in too small interference between the oil seal lip diameter and the shaft diameter after installation. Taking the crankshaft oil seal of S195 diesel engine as an example, this paper analyzes the main reasons for its lax sealing

The quality of oil seal is poor;

Poor quality of shaft or bearing;

Improper use and maintenance;

Improper installation;

Improper storage, resulting in adverse effects of environmental pollution.