Common desulfurization
pumps include fluorine lined centrifugal pumps, mortar pumps, stainless steel
pumps, etc. the seals include mechanical seals, power seals, double face seals
and packing seals, etc. What is the role of these seals?
1. Packing
seal
Put the compressible and resilient packing into the stuffing box, and
convert the axial compression force of the gland into radial sealing force, so
as to play a sealing role. This sealing method is called packing sealing, and
this packing is called sealing packing. Packing seal is widely used in pump
design because of its simple structure, convenient replacement, low price, wide
adaptability to speed, pressure and medium. When transporting normal temperature
media, the packing seal is generally equipped with a packing ring, which is
either connected with the high-pressure chamber of the pump or externally
connected with a certain pressure of liquid media, which can play the role of
cooling, lubrication, sealing or flushing.
As the packing seal is a contact
seal, there must be friction and wear problems. The size of friction and wear
mainly depends on the compression force of the packing gland. High pressure can
improve the sealing effect, but it will increase the power consumption and wear
of the shaft sleeve, otherwise it will produce large leakage. Therefore, the
pressing force of the gland should be adjusted according to the leakage volume
and the temperature of the leaking medium, and the packing should be replaced or
supplemented if necessary. The reasonable leakage of packing seal is generally
10-20ml/min. When introducing liquid from the outside, it should be ensured that
this liquid has good chemical stability, which will not pollute the medium
delivered by the pump, nor react with the medium to produce sediment and solid
particles. It should also have good impregnation and lasting retention with the
filler, so as to have a good and lasting sealing effect.
2. Power
seal
When the auxiliary impeller plus parking seal pump is running, the
pressure head generated by the auxiliary impeller balances the high-pressure
liquid at the outlet of the main impeller, so as to realize sealing. During
shutdown, the auxiliary impeller does not work, so the shutdown sealing device
must be equipped at the same time to solve the possible leakage during
shutdown.
The sealing structure of the auxiliary impeller is simple,
reliable, long service life, and no leakage can be achieved during operation.
Therefore, it is often used in pumps conveying media containing impurities. The
good sealing effect of the auxiliary impeller is conditional, that is, the
working pressure is not allowed to exceed the allowable working pressure. Once
exceeded, serious leakage will occur. The main reason for the change of working
pressure is the pressure change at the suction port of the pump. Therefore, for
the pump with auxiliary impeller seal, strict regulations must be made on the
inlet pressure of the pump, otherwise the seal will fail. Due to many forms of
parking seals, it is easy to find them after failure, so this article will not
repeat it.
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