Design Of Detection System For Relay Valve

Relay valve is one of the important devices of rail vehicle braking system,its performance directly affects driving safety,and inferior products cause serious hidden trouble to people’s life and property.At present,the detection of relay valve was mainly relied on the whole brake test bench,and the test steps are complicated,the precision and efficiency can’t be guaranteed.The tests are not complete,and the overall level of automation is low.In order to solve the above problems,it is very important to design a relay valve performance testing system with simple operation,high precision and high automation.The main contents of this research include the following aspects:(1)The internal structure and working principle of the automatic air brake system,especially the relay valve,are studied.The mathematical model of the relay valve is established through the analysis of the force balance of the internal piston and the mass equation of the gas flow.The simulation design and analysis are carried out with AMESim software,and the main characteristic curves are obtained,which provides reference and basis for the design of the follow-up testing system.(2)On the basis of the People’s Republic of China railway industry standard TB/T2552-1995 JZ-7 locomotive brake air relay valve technical conditions to develop a seven performance testing includes sealing,the dynamic response of the total air shutoff valve,booster stage decompression,piston sensitivity,supply valve,exhaust valve,and the overcharge.At the same time,according to the different testing requirements,such as time and pressure,the corresponding hardware module,data acquisition and control module and power supply module are designed.Combined with the upper computer testing software developed by LabVIEW,the automatic testing task for the comprehensive performance of the relay valve is realized.(3)The corresponding relay valve products are selected for multiple detection,and the important parameters of the collection are analyzed.The error sources of the detection system and the uncertainty of the system are judged by the data obtained by the repeatability detection.Combined with the evaluation method of national testing equipment,it has been evaluated.The results show that the testing system meets the acceptance requirements and achieves the expected design standard,and it is checked and accepted.