A hydraulic pump is a simple device in the system with the most important functions to perform. In hydraulics, the oil pressure determines how well the system will perform and what the output will be offered. It is the hydraulic pump that pressurizes the fluid in the reservoir and pumps it towards other machine components. In short, the hydraulic pump works for converting mechanical/electrical energy into required hydraulic energy. As mentioned, the hydraulic fluid passes through the pump to attain the required pressure. What if this hydraulic fluid is contaminated? How these contaminants affect hydraulic pump operation? What are the methods to prevent hydraulic pump failures? All these details are discussed in this article.
Hydraulic fluid contamination is one of the most serious concern for pump failure. Foreign particles like dust, rust, water, air, etc… entrapped in the hydraulic fluid will damage the pump and negatively impact system performance. Corrosion, damaged filters, seal failures, old hydraulic fluid, etc… are common reasons for hydraulic fluid contamination. The severity of hydraulic pump failure is directly related to the size and quantity of solid particle, system pressure and internal clearance of the components. Aeration, cavitation, fluid viscosity issues, excessive heat, implosion, and overpressurization are other reasons for pump failure.
Hydraulic pump contaminants can be categorized into built-in contaminants, ingressed contaminants, water/moisture contaminants, and internally/externally generated contaminants. During the manufacturing process particles like burrs, chips, cloth fibres and dirt that remain behind from the machining are called built-in contaminants. Contaminants like dirt, debris, water, etc... that enter the pump from outside through oil, worn/damaged filters and seals, open ports, etc… are called ingressed contaminants. Water/moisture in hydraulic oil is a serious contaminant that leads to corrosion and such contaminants enter in systems that operate in humid environments. Internally or externally generated contaminants results in cavitation, aeration, abrasion and parts failure.
Contaminants in the hydraulic pump will accelerate the component wear and shows different failure symptoms like noise, overheat, erratic operation of cylinders, and slow performance. If it becomes worse, finally the hydraulic pump will break down and the only solution then will be to replace the pump. Actually, it is not advised to replace the pump immediately whenever the pump fails to offer its maximum efficiency. Poor hydraulic pump performance can be a result of oil viscosity issues, leakage, inappropriate hose selection, etc.... In such instances, other than replacing the pump, it is suitable to troubleshoot and repair the cause of the pump failure.
Now, let’s consider how particle contaminants damage your pump. Small size contaminants like airborne dust in hydraulic oil will accumulate in between the moving parts of the hydraulic system and create friction. This will increase the component wear and leads to corrosion and other damages. When the contaminant is large particles, then this will create fluid leakage and low performance because of the surface to surface contact. Large size contaminants can also block the fluid passage and restrict pressure and fluid flow.
What are the methods to prevent hydraulic pump failure? Similar to all other hydraulic components, inspection and maintenance of components and hydraulic oil will eliminate most of the pump issues. It is also important to keep the workplace clean. While disassembling or repairing a hydraulic pump, the first stage to consider is cleaning the machinery properly so that no external particle enter into it. To prevent hydraulic pump failures resulting from built-in contaminants, it is advised to flush the pump and filters after complete installation. This will help to clean the entire system before the actual operation begins. If considering the ingressed contaminants and water/moisture contaminants, the entry of foreign particles can be restricted by using replacing worn filters, tightened fittings, and by carefully performing maintenance/repair operations.