Development Of Automatic Tester For Clay Methylene Blue Value

Clay is the most used binder for green sand. Clay content in the sand affects castingperformance and the quality of the castings directly. The quality of sand mold such as sandstrength, compactability, permeability, flowability, toughness and so on are closely linkedwith the clay content. The standard method for measuring clay content in sand is to testmethylene blue value. For now, the clay methylene blue value testing is completely doneby hand, using conventional glass burette dropping, relying on the operator to determinethe titration end point according to the testing standards. Manual inspection has manydeficiencies such as time-consuming. Testing the clay content in green sand fast andaccurately is great significance to improve the efficiency of the mold production and thecasting quality. To develop an intelligent automatic detection device for clay methyleneblue value is the core of this article.Although researchers have done some researching and studying in clay methyleneblue adsorption capacity testing automation, the market does not supply automatic devicesspecifically for the methylene blue value. After comprehensively comparing the titrationdevices for other applications, the paper elaborates on the rationality and feasibility of thedevelopment program in accordance with testing standards. And writer makes detaileddescription for the automatic dripping and the titration end point testing. The automaticdripping is a stepper motor driving peristaltic pump mode; the end point testing is to detectthe electrode potential of the composite glass electrode in mixture.Taking into account the automatic detector performance and cost requirements,hardware and software design principles is described in the paper. For hardware, aC8051F350microcontroller inserted a24bit AD converter is chosen as the core controldevice avoiding some other designs of signal acquisition circuit, making the entire circuitis more concise; program written in C51, the modular program structure of the program isclear and easy to modify and debug. As thermal components, the PT100is combined withprograms for temperature compensation of the automatic detector. Temperaturecompensation principle of the detector also made necessary instructions.Results show that the automatic detector has feature of fast testing, good accuracy,stability and performance, manages the requirements of clay methylene blue value testing.