After being used for 1 year, the concentricity still remained, Bill listed AAK a

Bill is a purchaser of Manitowoc company in the United States. Two years ago, AAK received an inquiry about hydraulic counterbalance valves from him, and there were few contacts later. Unexpectedly, two years later, we received an email from him consulting about the problems of the hydraulic counterbalance valves. After communication, we learned that a batch of hydraulic counterbalance valves he purchased elsewhere had problems and almost got into a big trouble.

Last summer, a crane shipped by their company, the crane winch system lost control during construction and the hook slipped off. Fortunately, there was no one under the hook at that time, otherwise there would be great trouble. According to the analysis of the field engineer, it is considered that the hydraulic counterbalance valve used in the crane winch system is abnormal. After disassembling the hydraulic counterbalance valve, it is found that there is a deviation in the concentricity between the valve spool and the valve seat. The valve spool is affected by large eccentric hydraulic force, so that the hydraulic counterbalance valve lost its function of balance and the hook slipped off.

After knowing the reason, Bill contacted the original hydraulic counterbalance valve supplier. The supplier replied that the hydraulic counterbalance valves were indeed within the warranty period, he can replace the abnormal hydraulic counterbalance valves with a new ones, but can not guarantee that each hydraulic counterbalance valve had the same concentricity and could be used for more than 1 year. Bill was worried about the stability of the new hydraulic counterbalance valves. He didn't want to have big trouble and had to find a new hydraulic counterbalance valve manufacturer.

In crane hydraulic system, the performance of hydraulic counterbalance valve is the cornerstone of winch system, and the consistency of hydraulic counterbalance valve concentricity is the key. Bill also asked other hydraulic counterbalance valve manufacturers. No factory guarantees that the concentricity of the hydraulic counterbalance valve can be still consistent after 1 year of use. Bill wants to know how about the concentricity of AAK hydraulic counterbalance valves after being used for 1 year.

We told Bill that perhaps having a try is the best answer. He can detect the concentricity of AAK hydraulic counterbalance valves in an all-round way. After 15 days, we sent 4 samples of hydraulic counterbalance valves according to his drawings. Seven days later, Bill informed us that the concentricity test data of AAK hydraulic counterbalance valves were indeed more comprehensive than that of his original manufacturer. How to ensure that the concentricity of AAK hydraulic counterbalance valves is still consistent after 1 year of use?

For some manufacturers, when processing the components of hydraulic counterbalance valves, there are discrepancies between the specification parameters and design, the standard of normal distribution cannot be reached, there are certain differences in between the structure of components and the concentricity of grooves, which is difficult to detect. AAK has Mahr cylindricity instrument imported from Germany.