Mechanical seal pressure issue?

The pressure within the mechanical seal chamber of a multi-stage pump is usually the pump’s suction pressure plus some of the pressure increase between stages; the exact value depends on the design and operating conditions of the pump. The pressure experienced by the mechanical seal is related to the pump’s outlet pressure, as the pressure throughout the system affects the performance of the seal; however, it is not exactly equal to the outlet pressure, as it is also influenced by the design of the balance lines and the pressure distribution within the pump. The pressure in the balance tube is generally used to regulate or balance the pressure within the mechanical seal chamber, in order to reduce the load on the sealing surfaces; therefore, it can be considered as the pressure of the mechanical seal chamber. .

Thank you very much, :handshake. In other words, if there is a pressure gauge on the balance tube, then the pressure on that tube is essentially the pressure in the sealed chamber. If there is no pressure gauge on the balance tube, how can one determine the pressure in the sealed chamber? How much is it approximately? The static pressure in an ordinary inlet pipe is around 1 kilogram. If there is no pressure gauge, can the static pressure in the inlet pipe be considered as the pressure in the sealed chamber? Furthermore, in single-stage centrifugal pumps, there are no balance pipes, and the impeller is located behind the mechanical seal. After the pump starts operating, the fluid is pressurized, and a portion of it enters the sealing chamber through the bottom sleeve. As a result, the pressure in the sealing chamber after operation should be higher than the pressure in the inlet pipe. What is this pressure typically? How should it be calculated? Thank you again; there’s a part I don’t quite understand.

For those with a balance tube, it is basically equal to the inlet pressure.

The pressure in the mechanical seal chamber, the flushing scheme, and the specific structure of the pump are interrelated, so it is not possible to generalize. For safety reasons, it can be set to pump inlet pressure + (0.15 MPa to 1 MPa)

The pressure within the mechanical seal chamber of a multi-stage pump is usually between the inlet pressure and the outlet pressure of the pump, depending on the pump’s design and operating conditions. Here are the key points: Mechanical seal chamber pressure: This pressure is generally close to the pump’s inlet pressure, but slightly higher, as the chamber is connected to the pump’s inlet via a balance tube, which serves to balance the axial forces and control the pressure in the seal chamber. Relationship between the pressure on the mechanical seal and the pump outlet pressure: The pressure acting on the mechanical seal comes primarily from the sealing chamber, rather than the pump’s outlet pressure. The pressure in the sealed chamber is usually close to the inlet pressure; therefore, the pressure experienced by the mechanical seal has no direct relation to the outlet pressure. Pressure in the balance tube: The pressure in the balance tube is usually close to the pressure in the sealed chamber, as it connects the sealed chamber to the pump inlet, serving to balance axial forces and control the pressure in the sealed chamber. Summary: The pressure in the mechanical seal chamber is close to the inlet pressure; the pressure experienced by the mechanical seal has no direct relation to the outlet pressure, and the pressure in the balance tube is close to the pressure in the seal chamber.