A hydraulic pump is the most important component in the hydraulic system and any malfunctions related to a hydraulic pump can bring severe damage to the entire system affecting performance and productivity. The issue of short hydraulic pump life can be a burden on machine operators and this can be costly because of frequent repairing or replacement. There are many reasons for hydraulic pump malfunctioning. But, the frequent occurrence of pump issues, requires a complete system inspection. The reasons can be contamination, wrong component selection, incorrect oil selection or others. These reasons for the hydraulic pump issues are analyzed in this article.
Contamination: Contaminants in the hydraulic system will change the oil properties and causes oil contamination. Also, sludge or varnish accumulated due to lack of maintenance or longer operation will also contaminate the fluid. These contaminants will reach the hydraulic pump through hoses/tubes when the system is under operation. The particle debris and oil contamination will increase the friction between pump parts causing corrosion and other wear that reduces pump lifespan. Undesired changes in fluid properties (especially, viscosity index(VI), fire resistance, compressibility, demulsibility, material compatibility, etc...) will also affect pump performance. For example, higher fluid viscosity will cause hydromechanical inefficiencies and lower viscosity results in leakages.
Wrong Pump Selection: Hydraulic pumps are of different types and choosing the ideal one is required for smooth and long-time operation. Pumps can be mainly categorized into piston, vane, and gear pumps. The factors to be considered for pump selection are pump inlet operation, working environment, flow rate & pressure, material compatibility, and more. Material compatibility is analyzed with the help of chemical compatibility charts.
Wrong Assembly of Components: Wrongly assembled hydraulic components can damage the pump. The wrong assembly means, incorrect insertion depth, improper valve adjustments, incorrect pump shaft rotation, and more. Among these, the incorrect hose insertion depth is the most serious concern. I.e; when the fittings are not attached properly, there is a high possibility for the fittings to blow off when exposed to high pressure. Checking the pump pressure compensator and relief valves are also required.
Pipe Geometry: The geometry of the pipes/hoses in the hydraulic circuit need to be considered when the hydraulic pump faces any issues. Too many twists and turns in the circuit will affect the fluid flow and lead to poor performance of the system.
Other reasons for hydraulic pump failure are overpressurization, cavitation, aeration, implosion and ageing.
Read more:Hydraulic Pump Cavitation: Learn from the Basics