Pilot Operated Hydraulic Relief Valves

Richard is a purchaser of ATOS company in Italy. Last September, ATOS received a complaint from a South African customer that the starting pressure of the hydraulic pump was often insufficient recently. The field engineer analyzed that the valve spool spring of the pilot hydraulic relief valve of the hydraulic pump was deformed, resulting in the unstable pressure of the hydraulic system. He tried to replace the pilot hydraulic relief valve to solve the problem. The customer questioned the stability of their equipment because it had been used for less than 1 year. After learning about it, the owner asked Richard to solve the customer complaint as soon as possible and replace this batch of pilot hydraulic relief valves. Richard wondered about the problem with the pilot hydraulic relief valve. This pilot hydraulic relief valve was produced by an American company and was re purchased this time. The original manufacturer replied that this pilot hydraulic relief valve has been produced according to the standard. The strength limit and elastic limit of the piano steel wire used meet the requirements. The problem should be caused by improper use by the user. Of course, he can not tell the owner of such results. The original manufacturer was unwilling to take responsibility. Richard contacted nearly 20 hydraulic valve manufacturers, including AAK hydraulic valve. After several rounds of communication, Richard eliminated half of the hydraulic valve manufacturers, and then asked the shortlisted hydraulic valve manufacturers to send their own ready-made pilot hydraulic relief valves. Their company conducted spring elasticity test. Finally, 5 manufacturers were selected to send samples for the second round according to the drawing size of his pilot hydraulic relief valve and improve the spring elasticity. After communicating with Richard, we learned that the service limit pressure of the hydraulic pump is above 350bar and the service frequency is very high. Although the piano wire spring used by Sun, the original American manufacturer, is advanced, special materials must be used for this special working condition. We started to test the special spring first. Richard has received samples of pilot hydraulic relief valves from other 4 factories, but AAK hasn't sent them yet. Richard pushed us several times and we advised that we are still in testing. Richard may think AAK should not be able to do it. AAK engineers spent 3 weeks, 6 times replacing materials and 9 times proofing, determined the special alloy steel spring as a trial, and sent the pilot hydraulic relief valve 30 days later. We specially asked Richard about the test of the pilot hydraulic relief valves from the other 4 manufacturers. Richard advised that if AAK pilot hydraulic relief valve could not pass the test, he would need a new round of looking for suppliers.