What are the flushing schemes of mechanical seals of commonly used devices in mechanical pumps

The purpose of flushing schemes of mechanical seals is to inject liquid directly into the high -voltage side of the dual or single mechanical seals. Generally, pumps especially light hydrocarbon pumps should be flushed.

1.Flushing and heat dissipation. The heat generated by the liquid mechanical seal must be controlled. This can be achieved by flushing the sealing cavity with liquid to take away the heat and thus controlling the temperature of the mechanical seal.

2.Reducing liquid temperature. In some cases, the high liquid temperature is too high to let the mechanical seals work normally. In such circumstances, the temperature must be reduced to improve the performance of the mechanical seal.

3.Changing the sealing pressure. In some cases, the pressure of sealing cavity of the mechanical seal is needed to increase or decrease to improve the seal performance. This can be achieved by suppressing evaporation or reducing the heat load of sealing parts of the mechanical seal.

4.Cleaning process liquid. If the process liquid contains inappropriate solid particles or pollutants, the liquid in the sealing cavity of the mechanical seal needs to be cleaned. In extreme cases, clean liquids may be provided from the outside of the sealing system.

5.Controlling the atmospheric side of the sealing part. Due to the contact with the atmosphere, the process liquid may become dry, crystallized or scorched. It is very important to prevent its interaction with the atmosphere to avoid adverse effects on the sealing performance of the mechanical seal.

Classification of flushing schemes of mechanical seals

◆ Single Seals

PLAN 01 (Single self -flushing)

PLAN 02 (Cooling with coats)

PLAN 11 (self -flushing)

Plan 13 (reverse flushing)

Plan 14 (Positive+reverse flushing)

Plan 21 (self -rushing with cooling)

Plan 23 (internal flushing of the circular set)

Plan 31 (self -rushing with a suspension separator)

Plan 32 (outer rushing)

Plan 41 (self -rushing with suspension separator, self -rushing of heat exchanger)

◆ Dual seals

PLAN 52 (tandem seal with unpressurized buffer tank)

PLAN 53A (double seal with a pressurized sealing solution seal)

PLAN 53B (double sea of the compulsory cycle sealing solution)

PLAN 53C (double seal with pressure increase tank)

PLAN 54 (double seal with external sealing liquid)

◆ Cooling seal (quench seals)

PLAN 62 (outer flush or quench to prevent the mechanical seal from accumulating solid particles)

PLAN 65 (measured the seal leakage with the floating subdividation switch)

◆ Gas Seals

PLAN 72 (use isolation nitrogen on medium easy to volatile of tandem gas seal)

Plan 74 (double dry gas seal)

PLAN 75 (tandem dry gas seal for not easy to volatilize media)

PLAN 76 (sealing the tandem dry seal with external sealed gas)