Hydraulic piston pumps are the most expensive and, at the same time, the most durable hydraulic pumps. These types of pumps are used in both open circuit and close circuits in the industrial and mobile hydraulic field. The hydraulic piston pump is the best and most suitable choice for use in circuits with a high working pressure of up to 700 bar. In this type of pumps, the tolerance between the pistons and the cylinder is very low, and the low tolerance between the piston and the cylinder makes this type of pump less tolerable than other hydraulic pumps. In order to increase the life of the pump, the two components of the purification of the pump oil and Non-contamination of the pump's work environment is very important.