Mechanical seal API682 standard seal arrangement method-

Mechanical seal API682 standard seal arrangement

　2019-08-07　　

The sealing arrangement of the mechanical seal API682 standard:

In addition to the above three basic types of standard mechanical seals, three types of seals for layout are also specified, but there will be some changes when selecting them according to the data sheet, as described in Table 7-2. Sand mill mechanical seal

Table 7-2 Three arrangements of mechanical seals for centrifugal pumps and rotor pumps

In addition, what needs to be explained is:

① Regardless of the arrangement and type of seal used, static mechanical seals are used when the peripheral speed is greater than 25m/s.

③ Suppression seal ('CS': ContainmentSeal) is an outer seal in a non-pressurized tandem arrangement. According to different working conditions and requirements, contact mechanical seal 'CS' or non-contact mechanical seal 'NC' can be selected. When the inner seal fails, according to the design requirements, it will operate at least under the condition that the sealed chamber is full of process fluid, and can prevent the process fluid from leaking into the atmosphere or minimize the amount of leakage into the atmosphere.

Suppressive sealing is designed for long-term operation under relatively poor working conditions. Its function is to isolate the suppression seal cavity from the atmosphere during the operation of the machine. According to the standard, the pressure in the sealed cavity should be less than 7030.7Pa. In fact, the inhibiting seal does not actually start to work until the primary seal fails. In this case, the inhibiting seal may work in an environment of high-pressure steam or process fluid. The quality qualification test is designed for the failure of the inner main seal under normal operation. During the test, the key points of leakage and pressure loss will be monitored and recorded.

Figure 7-1 shows the sealing types used under different sealing arrangements.

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