Networked Measurement And Control Systems For Mechanical Seal Testing Device

Mechanical seals are widely used in chemical industry, water conservancy, and shipping,its performance direct impact on the safety and reliability of related equipments. To promote thedevelopment of mechanical seals, it is essential to adopt high-performance test devices. In thistopic, virtual instrument technology and network communication technologies were introducedto the design of the performance test device for mechanical seals, and developed networkedmeasurement and controlling systems for mechanical seals testing device based on virtualinstrument technology. This system will not only collect, display, store and process the signal ofmechanical seals' performance parameters, but also enable remote monitoring and networksharing of test data. The main contents and results are listed as follows:(1) Based on the principle of mechanical seal testing, considering the common test systemand technical of virtual instrument network, the paper put forward mechanical seal test deviceincluding network.(2) Based on LabVIEW2009software, the paper discussed the planning of construction ofnetwork mechanical seals test syetem. B/S model was proved very flexible and simple. But it isrestricted by IE communication mode. C/S model can make full use of server's and customer'shardware resources, but it will meet difficulties when upgrade.(3) The paper investigated the method of measuring mechanical seal performanceparameters and the type of test signal, completed assembly and adjustment of the hardware.After choosing floating ground signal sensor and USB bus acquistion card, a anti-interferencehardware system was constructed based on difference measurment mode.(4) Completed the development of mechanical sealing performance test and controlsoftware. Based on the concept of modular design, dividing the control system which meetusers' function requriments into several subVIs, after finishing every subVI's programming anddebugging, host program dynamically invoke every subVI, eventually, the system with featuressuch as data acquisition, analysis, display and storage is completed.(5) Making a test resesrch on the end face temperature of mechanical seal which is running.Exponential curve fitting and polynomial curve fitting fit four signals measured bythermocouples. Selecting the small difference of fitting function and calculating the sealing endtemperature. The test results are show that: under the normal working condition, the end facetemperature of mechanical seal is the same as the sealing medium, meanwhile, the measuredtemperature signal follow polynomial function distribution along the axial direction; But underthe special condition, such as under the dry friction condition the end temperature will suddenly increase, meanwhile, the measured temperature signal obeys exponential distribution along theaxial direction.(6) Through testing to compare the three technologies-Web, TCP/IP and DataSocket,Finalize system networked by DataSocket. Web technology can't dispose test data much further,programming with TCP/IP technology is complex, programming with DataSocket technology isnot only very easy, but also easy to read the data for further processing.In the system written byDataSocket technology, the server do not need to communicate with the clients directly, justneed to load a separate independent DataSocket Server, and send data to this server, clients canread data from the server, so the purpose of remote testing is achieved.