The hydraulic pressure relief valve was delivered in 15 days by AAK

On Monday afternoon, I received an email from Tony. Tony is a purchasing manager of CASAPPA in Italian, mainly responsible for the purchasing of hydraulic pump components, and the work has been very smooth. Last month, they received a complaint from the largest customer that the pressure at the outlet of the hydraulic pump sometimes rises by itself, resulting in unstable operation of the equipment. The customer's site engineer couldn't solve it and turned to CASAPPA for after-sales service. Although the warranty period has expired, they still need to help customer solve the problem. Their engineers tested various parameters of the hydraulic pump. After comprehensive analysis, they were still uncertain about the root cause, but they suspected that the hydraulic pressure relief valve in the pump is faulty.

The engineer asked Tony to contact the original supplier of the hydraulic pressure relief valve and ask him to send a sample of the hydraulic pressure relief valve for replacement and test. It is a local hydraulic valve manufacturer and they still have samples in stock. After receiving samples and commissioning, the engineer's suspicion was proved to be correct. After replacing the hydraulic pressure relief valve, the hydraulic pump worked normally. Tony asked the original hydraulic valve manufacturer to urgently replenish 30 hydraulic pressure relief valves to solve this complaint. The manufacturer said that the shipment has passed the two-year warranty period. At present, there are only 3 samples in stock. The remaining quantity needs to wait in production schedule for production, and can only be delivered after 3 months. If offering this plan to the big customer, Tony would be scolded by the boss. He thought of AAK, because the hydraulic valve failed last year, which was also solved by AAK.

Tony established a business relationship with us last October. Now we are also friends besides business. We often discuss the knowledge related to hydraulic valves. His email on Monday is just to ask for help on this hydraulic pressure relief valve. After knowing these conditions, I asked him to send us samples of those faulty hydraulic pressure relief valves, and provide us the drawings of this hydraulic pressure relief valve, noting those special requirements.

After receiving and disassembling the samples from Tony, we found that the main valve spool of the hydraulic pressure relief valve was too loose and had increased leakage, then the pressure at the oil outlet increased. The problem should be caused by high-frequency wear or insufficient accuracy of the original shipped hydraulic pressure relief valve. The engineer of CASAPPA asked us to reply why it was determined that it was the problem of the valve spool? Because in the pressure reducing control circuit, after the directional valve works, the flow at the valve outlet becomes zero, but the pressure still maintains the originally set pressure. In this case, the flow through the pressure reducing port is only pilot flow.