Hydraulic Relief Valve

When I opened the mailbox this morning, I saw an from , which should be a re-order for the hydraulic relief valve, because he asked about the durability of hydraulic relief valve spool last week. Opening the , it is indeed the need for purchasing a large number of 420 hydraulic relief valves, and requiring 3 years of quality guarantee. is a purchaser of . 3 years ago, a customer of his company complained that the crane was easy to depressurize during work, resulting in the inability of the crane to bear the force. Especially after the working temperature reaches 55 C, the pressure cannot go up. Field engineers believe that this is a problem of the hydraulic system, such as low pressure regulation of the hydraulic relief valve, wear of the hydraulic system, or oil pollution. No abnormality was found after inspection. Finally, it was determined that the fault occurred on the hydraulic relief valve. After disassembling the hydraulic relief valve, it was found that the cone valve spool was worn, affecting the sealing of the hydraulic system, so the oil pressure could not rise. The customer does not understand why the valve spool of this hydraulic relief valve is worn after less than 2 years of use. The customer requested to replace with a batch of hydraulic relief valves with durability of more than 3 years and use them on these 12 faulty cranes. At that time, contacted more than 10 hydraulic relief valve manufacturers and got reply that the warranty could not be achieved for 3 years. Some hydraulic valve manufacturers replied that they only have 50% confidence. This result embarrassed Bruce. The customer requirements for the hydraulic relief valve could not be implemented, how he should explain to the owner. I received message from on the of can really provide a 3-year warranty hydraulic relief valve I replied directly: just give it a try then you will know. I can't make money with the trial orders of several samples, and you can't lose money. Maybe was stimulated and sent us the test order the next day for 4 hydraulic relief valves. also frankly told that two other hydraulic valve manufacturers would also try the order at the same time. Their plan is that each factory will be tested for 4 samples, with a total of 12 hydraulic relief valves to meet the urgent needs of customer first. About 2 years after the samples were sent, we received from again for another trial order of 8 hydraulic relief valves. I felt strange and thought that they actually didn't have big quantity order for hydraulic valves. Until last week, from his email, we learnt that they had tested the hydraulic relief valves provided by for 3 years. Indeed, 3 years later, hydraulic relief valves still worked normally, and the hydraulic relief valves provided by the other two manufacturers had faults in less than 2 years.