Hydraulic Directional Control Valves Noise

HIGINSON company plans to develop a new plunger hydraulic cylinder, which needs to purchase the supporting hydraulic directional control valves. Helen, who had just joined the company, stumbled when purchasing the hydraulic directional control valves. Helen has no hydraulic valve supplier and can only purchase from the original hydraulic valve manufacturer of the company. Half a month later, the engineer and technician of the company installed the hydraulic directional control valves purchased by Helen for commissioning, and the plunger hydraulic cylinder dropped intermittently with vibration and noise. The technician pointed out that the hydraulic directional control valves needed to be replaced. Helen contacted the original manufacturer of hydraulic directional control valve. Per the manufacturer, the delivered hydraulic directional control valves met the requirements of Helen's parameters, and the accuracy also fully met the standard. As a novice, Helen was helpless, and the technician did not specifically say why to replace the hydraulic direction control valves. She tried to contact the new hydraulic directional control valve manufacturer to solve the problem. Helen left a message on AAK website: why is the plunger hydraulic cylinder equipped with hydraulic directional control valve noisy? At this moment, we can't tell the reason. After communicating with Helen, I learned the process of purchasing this hydraulic directional control valve and the judgment of technician in their company. AAK engineers are not 100% sure that where the problem is according to the hydraulic directional control valve drawings sent by Helen, the shipment sample of the original manufacturer and the video of their technician's machine test. We are thinking if Helen, as a novice, has mistaken the type of hydraulic directional control valve? The hydraulic directional control valves can be divided into internal leakage type and external leakage type. Combined with the working conditions, this plunger hydraulic cylinder just reverses the oil outlet chamber, and the back pressure is high. If the internal leakage hydraulic directional control valve is used, there will be abnormal phenomena such as vibration or noise. We told Helen our thinking. She really did not note to the original manufacturer that the hydraulic directional control valve is internal leakage or external leakage. I told her that AAK has ready-made samples of the external leakage hydraulic directional control valve. It is recommended to test the machine with AAK hydraulic directional control valve to see if there is still vibration or abnormal noise. A week later, Helen sent an email saying that AAK hydraulic directional control valve was installed and there was no abnormality in the test run.