Factors affecting the life of the mechanical seal of the G single-screw pump

G single screw pump mechanical seal is one of the common wearing parts of the water pump, but if it is used or installed improperly, it will cause the mechanical seal to be more easily worn and leaked, so we should pay attention to what aspects and which ones will affect the mechanical seal The life expectancy is summarized below for your reference:

1. The axial force is too large. The mechanical seal cannot withstand axial force during use. If there is an axial force, the impact on the mechanical seal is serious. Sometimes due to the unreasonable design of the axial force balance mechanism of the pump and the reasons of manufacture, installation and use, the axial force is not balanced. The mechanical seal is subjected to an axial force, and the temperature of the sealing gland will be high during operation. For polypropylene media, it will be melted at high temperature, so the sealing effect will be lost soon after the pump is started, and the sealing end face will appear when the pump is stationary. Intermittent leaks.

Second, the deflection of the G single-screw pump shaft is too large. Mechanical seal, also known as end face seal, is a kind of contact dynamic seal in the axial direction of rotation. The sealing effect is therefore required to be uniform between the two seals. However, due to the unreasonable design of the pump product, when the pump shaft is running, the deflection at the installation location of the mechanical seal is large, which makes the force between the sealing surfaces uneven, resulting in poor sealing effect.

Third, the reasons for pump cavitation. Due to the unreasonable operation of the device system, the poor cavitation performance of the pump inlet, and the high speed of the pump, local cavitation occurs at the pump inlet. After the cavitation occurs, there will be bubbles in the water, which will impact the mechanical sealing surface on the one hand. On the other hand, the flow film of the mating surface of the dynamic and static rings will also contain air bubbles, which cannot form a stable flow film, resulting in dry friction of the mating surfaces of the dynamic and static rings, and damage to the mechanical seal.

4. There is no auxiliary flushing system or the setting of the auxiliary flushing system is unreasonable. The auxiliary flushing system of the mechanical seal is very important, it can effectively protect the sealing surface, and play the role of cooling, lubricating, and washing away debris. Sometimes the designer does not configure the auxiliary flushing system reasonably, and the sealing effect cannot be achieved; sometimes although the designer designs the auxiliary system, due to impurities in the flushing liquid, the flow and pressure of the flushing liquid are not enough, and the design of the flushing port is unreasonable. , also can not achieve the sealing effect.

Fifth, the vibration is too large. The vibration of the mechanical seal is too large, which eventually leads to the loss of the sealing effect. However, the reason for the excessive vibration of the mechanical seal is often not the cause of the mechanical seal itself. Other parts of the pump are the source of the vibration, such as the unreasonable design of the submersible sewage pump shaft, the reasons for processing, the lack of bearing accuracy, and the parallelism of the coupling. difference, large radial force, etc.

Six, the machining accuracy is not enough. There are many reasons for the insufficient machining accuracy. Some of them are the insufficient machining accuracy of the mechanical seal itself. The reasons for this are easy to attract people's attention and easy to find. But sometimes the machining accuracy of other parts of the pump is not enough, and this reason is not easy to attract people's attention. For example: the increase of the accuracy of the pump shaft, shaft sleeve, pump body and sealing cavity is not enough. The existence of these reasons is very unfavorable to the sealing effect of the mechanical seal.