Function of multi-stage pump balancing device for coal mine drainage
The function of the multi-stage pump balancing device for coal mine drainage:
The impeller of the multi-stage pump for coal mine drainage has an axial thrust force, which is difficult to fully bear only by the axial thrust bearing of the pump. An axial force balancing device must be installed. The reason for the axial thrust is mainly caused by the imbalance of the fluid pressure acting on both sides of the impeller. The multi-stage pump for coal mine drainage is generally equipped with a balancing device. The structure of the balancing disk device is composed of a balancing disk, a balancing seat, and an adjusting sleeve (some balancing disk and adjusting sleeve are integrated), which improves the service life of the pump. It has a reasonable structure and operation. It has the advantages of stability, axial force balance, long bearing service life and extended working time of the pump.
The working principle of the balance disc is: the liquid with pressure from the last-stage impeller flows into the water chamber between the balance plate and the balance seat through the radial gap between the balance seat and the adjusting sleeve, so that the water chamber is in a high-pressure state . Behind the balance plate, a balance pipe is connected to the inlet of the pump, and its pressure is approximately the inlet pressure of the multi-stage pump. In this way, the pressure on both sides of the balance plate is not equal, and a backward axial balance force is generated. The magnitude of the axial balance force changes with the change of the axial displacement, adjusting the axial gap between the balance plate and the balance seat (that is, changing the pressure of the water chamber between the balance plate and the balance seat), so as to achieve the purpose of balance. But this balance is often dynamic.
The axial force balancing device of the multi-stage pump for coal mine drainage is provided with a pump body, a pump shaft and an impeller. It is characterized in that the multi-stage pump shaft is provided with a balancing disk seat and a balancing disk, and the inner wall of the balancing disk is fixedly connected to the pump shaft. The outer wall is movably connected to the balance plate seat, and one end is connected to the impeller. The balance plate seat is fixedly connected to the rear section of the pump body to form a fluid gap between the balance plate seat and the balance plate. When the fluid passes between the balance plate seat and the balance plate During the fluid gap, due to the relative movement between the balance disc and the balance disc seat, a water ring is formed between the fluid gap to achieve the function of dynamic sealing, resulting in a drop in fluid pressure, which causes the pressure in the lower cavity of the balance disc to be greater than that of the upper cavity The pressure will balance most of the axial force generated by the impeller.
When the multi-stage pump for coal mine drainage is running, because the axial force generated by the impeller is greater than the axial force on the balance plate, the pump moves in the direction of the pump inlet, so that the gap between the balance plate and the balance ring is reduced. When the high-pressure liquid passes through the gap, the resistance increases and the leakage decreases, so that the pressure between the balance plate and the balance ring rises, increasing the balance force on the balance plate until the balance force is equal to the axial force. The axial clearance remains unchanged. Conversely, when the axial force is less than the balance force, the pump axis moves to the right, the gap increases, the high-pressure liquid leakage increases, the pressure between the balance plate and the balance ring decreases, and the balance force acting on the balance plate decreases until Until the axial force generated on the impeller is equal, keep the axial clearance running under a certain clearance.
