What are the requirements for the sealing fluid used for flushing of mechanical seals

Auxiliary facilities for mechanical seals refer to lubricating, cooling or temperature-regulating, flushing, purifying, diluting and flushing away the leakage medium to improve the working environment of the mechanical seal by means of flushing, cooling, filtering and separation.
The primary mode of operation of all ancillary facilities of mechanical seals is flushing.

For self-flushing, the flushing fluid is the sealed medium itself. For circular flushing and injection flushing, the sealing fluids and the sealed medium are different, and some requirements are put forward for the sealing fluids.

1)The flushing fluid should be clean, non-corrosive, compatible with the medium in the pump, and have good lubricity at working temperature. 2) The flushing liquid will not affect the product quality if it enters the pump, and if it leaks out, it will not pollute the environment and have no other adverse effects. 3) The flushing liquid entering the pump will not affect the operation of the pump. For example, pumping down and cavitation are not caused. 4) The flushing fluid has good thermal conductivity and can conduct heat out in time. The washing temperature should meet the working requirements. 5) The price of the flushing solution should be low. The amount of flushing should be controlled and not too much, which is necessary for energy saving and consumption reduction. The choice of which fluid to use as the flushing fluid is flexibly controlled according to the specific conditions.

For example, for an alkylation unit that uses concentrated sulfuric acid as a catalyst, the ordinary 104-type mechanical seal has a shorter service life because of severe corrosion. It is impossible to use self-flushing, so injection flushing has to be used. So what fluid to choose as the flushing fluid? Diesel certainly is OK, but the device cannot be used without water, which will affect production and aggravate corrosion. According to the requirements of the flushing liquid, the reaction product of the device is finally selected - a mixture of carbon 4~carbon 9. The mixture does not reduce the concentration of the acid after it is sealed into the pump, and enters the reactor through the pump together with the acid, and only a small amount of reaction product circulates between the pump and the reactor. The mechanical seal device’s working environment is improved and the working life is prolonged.