The pressure holding time of AAK hydraulic valve block is 3 times that of its pe

The guard told me on Monday that there was an international parcel in the office. From the shipment airway bill, it was a sample of hydraulic valve block from an old American customer Zero. I was a little puzzled. Zero only purchases hydraulic cartridge valves from AAK. I didn't know why he sent me the hydraulic valve block sample until I read all the emails today.

Zero introduced in the email that he purchased this hydraulic valve block from a friend, the quantity was not big, just 100 pieces. The hydraulic valve block was easy to leak after being used for a period of time. He didn't know the source of the leak and asked me to help have a check. After the pressure test and inspection, our technician analyzed that the leakage was serious and the pressure could not reach the pressure value of the system. I told Zero that the original manufacturer of this hydraulic valve block judged that the hydraulic valve block was qualified without strictly controlling the data in the pressure test stage.

For this kind of hydraulic valve block, AAK did this in the pressure test stage, and this method has been used since 5 years ago. After the production of the hydraulic valve block is completed, start the pressure test. First, adjust the throttle valve opening on the hydraulic valve block to the maximum, and at the same time, adjust the pressure valve adjusting spring to a very loose state, and then gradually increase the pressure. When the pressure reaches the required test pressure, our pressure holding time is 10min, while the pressure holding time of most hydraulic valve block manufacturers is 3min. The problem is easy to be exposed if the pressure is maintained for a long time. If there is leakage during the pressure maintenance, the source can be traced, and special treatment of sealing glue can be added at the joint surface. At the same time, after the test is completed, adjust the relief valve on the hydraulic valve block to the set pressure value required by the system to achieve the internal pressure balance of the valve block system. Few manufacturers do this step.

Zero realized that only AAK could ensure that there was no leakage in the hydraulic valve block, so he asked me to arrange 100 hydraulic valve blocks on the production line in a hurry. The pressure maintaining test is the key to check the leakage, but to produce a leak-free hydraulic valve block, AAK do these in production: first, select the appropriate processing material according to the working conditions of the customer's hydraulic valve block, and ensure that the internal organization of the processed valve block material is dense, without foreign objects, sand holes and other defects. If necessary, flaw detection will be carried out on the blank material. Secondly, the control of machining precision is also very strict, and the machining of all threaded holes on the valve block is guaranteed to be above 7H; In addition, the perpendicularity tolerance between the screw hole of the installation pipe joint and its external mating surface shall be at least Class 8.