Study on the balance force regulation method of multi-stage pump balance drum system

Balanced drum systems are widely used in high-pressure multi-stage pump axial force balancing mechanisms. When the pump working, the fluid (solid-fluid mixture) collides with each other or rubs against the pump case, and the balance drum is affected by this situation for a long time, so wear of the balance drum gap occurs from time to time. The first is to study how the axial force of the multistage pump changes at different balance drum gap sizes in this paper. Based on the energy equation and momentum equation, and on the basis of maintaining the original balance force unchanged, a new equation of resistance pressure difference relationship is established. The corresponding relationship between balance drum gap and balance pipe orifice plate is obtained by solving this equation. The result shows that the larger the balance drum gap, the greater the balance drum balance force decreases obviously, and the multistage pump residual axial force increases in multiples. The adjustment formula of balance force can be used to obtain the radial size of the balance pipe orifice plate under different balance drum gap, when the gap increases, to keep the balance force constant, the diameter of the orifice plate should be increased gradually. After adjusting the balance force, the fluid velocity uniformity and velocity average angle of balance pipe increases, the flow pattern in the pipe becomes uniform, the gap leakage increases and the pump efficiency decreases. The pump hydraulic properties and balancing the axial force have an opposing relationship, that is, by promoting the drum balance force, the pump hydraulic properties will be reduced. Due to processing balance drum is complex, frequent replacement is time-consuming and costly, so this article provides a handy approach for enhancing the balance force of balance drum, the results of the study can provide guarantees for the balance drum system optimization and long period stable operation of the multistage pump.