Hydraulic Check Valves

Last Friday, we received 3 emails from Niki, they are all the order for a same hydraulic check valve, but only the ship to address is different. It is the first time for their company to place the orders of 1,500 hydraulic check valves at one time. Niki is a purchaser of a Dutch hydraulic equipment company. Last year, a boarding bridge equipment needed hydraulic check valves. At that time, he planned to purchase from old suppliers. Unexpectedly, after dozens of hydraulic check valves from the initial samples were installed on the boarding bridge and tested for less than a month, the boarding bridge will slowly decline automatically. The engineer judged that the hydraulic system did not maintain the pressure, and it is likely that some hydraulic check valves leaked. However, after disassembling and inspecting the hydraulic check valves, it was found that the matching clearance accuracy of the valve spool and valve sleeve was within the normal range, and there was no jamming. Niki contacted the hydraulic check valve manufacturer, and manufacturer also didn't know why the hydraulic check valve leaked, so they could only replace those leaking hydraulic check valves. Niki is a little worried that if the leakage source of the hydraulic check valve is not found and replaced blindly, there may be a bigger problem later. Niki was not satisfied with the old supplier and had to start looking for new manufacturers of hydraulic check valves again. AAK received message from Niki on our website: what are the reasons for the leakage of hydraulic check valves? I realized that there was a leak in the hydraulic check valves purchased by Niki, but he hasn't found the root cause. After receiving the drawings of hydraulic check valve and the working conditions of boarding bridge equipment provided by Niki, we still can't 100% determine what caused the leakage of hydraulic check valve. We suggest him send us one of the previously leaked hydraulic check valves for analysis. After dismantling, our engineer is 90% sure to understand the root cause of the leakage, but still need to try sample to make it 100% sure. Niki is also willing to allow AAK to make samples according to his hydraulic check valve drawing. One month later, we sent 12 samples of hydraulic check valves to Niki and told him that the leakage of the hydraulic check valves from original manufacturer should be caused by poor details in production. There will be a certain gap between the cap and the thread of the valve sleeve of the hydraulic check valve. How to seal this gap is not only the detail but also the key, especially for the equipment with high working conditions. AAK uses thread anaerobic adhesive, which can completely fill the gap, enhance the sealing or retention force of mechanical connection components, prevent thread loosening and leakage due to vibration between the cap and valve sleeve of hydraulic check valves, and protect the joint from corrosion. Few hydraulic valve manufacturers