Continuing the problem of the mechanical seal static ring o-ring last time, it leaked again! Please help????
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Horizontal centrifugal pump, medium diesel, working pressure 3Mpa, large spring single seal. After using it for a week, the user discovered that oil stars flew out between the sleeve and the gland. Now the leakage has increased and there are oil droplets. What is the problem? The fluorine rubber O-ring inside the shaft sleeve is relatively tight during assembly. When the static ring O-ring is pressed in, it is also quite close. I need to apply butter before pressing it in. The specific pressure is not too small, and if it is too high, it is afraid of ablation. There are still moving ring O-rings and moving and static ring end faces. The contact surface between the dynamic and static rings is relatively narrow. I don’t know if I made it clear? I really can't find the problem. Thank you all! Also, I would like to ask what the function of the white pad on the shaft is, it is cut by hand. There is already an O-ring inside the shaft sleeve. How much sealing effect will this white gasket have?
What material is the ring surface of the mechanical seal made of? Is it graphite versus silicon carbide? The seal is balanced or unbalanced. The working pressure of 3MPa you mentioned refers to the outlet pressure. The non-driving end seal chamber pressure of the multi-stage pump is slightly higher than the inlet pressure.
This white pad can be used to adjust the compression amount of the mechanical seal and also plays the role of sealing medium! Disassemble the mechanical seal and check carefully to find out where the leak is.
The compression ratio of the mechanical seal is large, and the high temperature ablation seal ring causes the seal cavity pressure at the non-driving end of the multi-stage pump to be slightly higher than the inlet pressure, causing the axial outlet end to shift and increase the compression ratio.
Too few photos taken! Take more photos of the key shaft sleeves, machine seals, balance plates, rings, and appearance bearings, and explain in detail the working conditions of the pump, inlet and outlet pressure, temperature, vibration, flow head, etc.!
1. The PTFE gasket on the shaft shoulder is used to adjust the compression amount of the mechanical seal.； (Adding padding increases compression) ； 2. According to the phenomenon mentioned by the poster, the fault is most likely caused by the sealing friction pair~~~ Directions for rectification: 1) Recalculate the seal compression amount ； 2) Change to small spring 3) Change to PLAN32
Whether the mechanical seal meets the requirements for diesel use, the white pad is to adjust the compression amount. If it is a new mechanical seal, if it meets the requirements for diesel use, the compression amount of the mechanical seal is insufficient.
Adjust the axial installation position of the shaft sleeve so that the positioning ring can be properly stuck in the positioning groove of the shaft sleeve. This is the design and installation position of the mechanical seal
Normally it should be like this. Can you see what kind of transmission its bushing is? I guess it is key transmission. The driving method and positioning method of the bushing are not visible from the picture. There is no clamping mechanism at the rear of the sleeve to fix it to the shaft. It can only be positioned through the pillow block.
There should also be a short sleeve here, which clamps the mechanical seal sleeve transmission through the lock nut.
The structure of the DG boiler feed water pump has a bearing pushing against a short sleeve. It should be driven by a key, and it cannot rely on friction.