After adding PTFE retaining ring, AAK hydraulic check valve does not leak, Eddy

Last week, Eddy emailed me that after AAK hydraulic check valves of the test order has been used for 3 months , the O-ring seal was still free of wear. He was finally relieved. Eddy, who works at Terex company in the United States, has successfully purchased hydraulic valves from China over the years, and his boss is also very satisfied. At the beginning of last year, a customer complained about the hydraulic equipment supplied by their company for offshore oil field exploitation, which made him very passive. Some equipment has the phenomenon that the drilling machine rises slowly or cannot rise. Their engineer found that the hydraulic check valves used in the oil circuit of the hydraulic equipment had internal leakage, the one-way oil circuit could not be fully locked, resulting in the inability of the equipment to rise. Their engineer can only replace the hydraulic check valves with the previous spare ones and bring the problematic hydraulic check valves back to the company. Eddy sent these hydraulic check valves to the original supplier. The supplier replied that the reason for the leakage in the hydraulic check valves was that the ambient temperature was too low. The O-ring seal of the hydraulic check valves was hardened and worn quickly in extremely cold conditions, which was difficult to solve. Eddy knows that if he can't give reply to customer like this, he must find a manufacturer who is able to produce the hydraulic check valves working at low temperature. Eddy contacted several hydraulic check valve manufacturers, most of them reported that it was difficult to achieve 100% leakage free under such extremely cold conditions. Eddy was worried.

When Eddy contacted us, our engineer wanted to see the real reason for the wear of the O-ring of his hydraulic check valves and asked him to send the defective hydraulic check valves. After receiving the samples, our engineer realized that even if the cold resistant O-ring is used, it may not be 100% leak free, and the structure of the sealing ring needs to be changed, because the internal structure of this hydraulic check valve is a little complex. Eddy said that this is the only different reply he received. It seems that Eddy still doesn't believe that AAK can solve the leakage problem of the hydraulic check valves.

I told him that a Russian customer has purchased hydraulic relief valves from us, and their hydraulic equipment is also used in oil fields. The customer told us that under extremely cold conditions, the service life of AAK hydraulic relief valve is more than 4 times that of its peers. Three weeks later, we sent 4 pieces of hydraulic check valves of the test order to Eddy. There was no news after 3 months. Until last week, we received email from Eddy amazing that their engineers also admired our idea of adding retaining ring to the O-ring of the hydraulic check valves.

I told Eddy that the installation of retaining ring can play the role of axial fixation, reduce the gap between the O-ring and the low-pressure side of the seal, and prevent the O-ring from being 'extruded'. At the same time, the structure of O-ring added with retaining ring will bear much greater pressure than when the O-ring is used alone, which reduces the wear of the O-ring.