Xiaobai has a question: I can’t understand the data sheet for control valves provided by the design institute
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Xiaobai has a rather basic question: There are many items in the control valve data sheet provided by the design institute that I don’t understand. Could everyone please take a look at them? 1. The allowable noise level – does the noise referred to here mean the sound generated when the valve is in operation? What impact does noise have on valves? Why is this needed to be shown in the data table? 2. Regarding seals, there is Telfon (i.e., PTFE) and GRAPHITE. What is the difference between these two? In what occasions are they used respectively? 3. Parameters related to pressure: 1) The pressure value can be normal or maximum. 2) The differential pressure value has three levels: minimum, normal, and maximum. Where are these pressure values and differential pressure values used? Why does the design need to provide this data? (A very basic question -_-!) 4. What do these 5 parameters below mean? What’s the use? Thank you
First, noise refers to the sound generated during the operation of the valve; this noise level must comply with relevant standard specifications and must not exceed a certain threshold in decibels. Secondly, Teflon, whose scientific name is polytetrafluoroethylene, and the graphite filler is made by weaving flexible graphite fibers together; it is suitable for use as a static filler seal at high temperatures, with a maximum operating pressure of 30 MPa. Its operating temperature range is from -200 to 650 degrees Celsius, and it is black in color. There are two types of existing polytetrafluoroethylene packings: one is made from polytetrafluoroethylene dispersion resin, while the other is made using polytetrafluoroethylene suspension resin from which fibers have been separated as the main material. The former is softer while the latter is harder; both have the same corrosion resistance. Their maximum operating temperature is between +200 and -200 degrees Celsius, and they are white in color. Compared to graphite, polytetrafluoroethylene has inferior high-temperature resistance, but its corrosion resistance is better than that of graphite; it can be used in a wider range of applications for sealing in various special environments. However, its price is higher. Thirdly, pressure value: this refers to the pressure level under normal operating conditions. Maximum value: The highest pressure that the valve can reach under special operating conditions as well as in the most severe combinations. The pressure difference is the difference between the pressure at the outlet and that at the inlet, and it can be divided into three situations as well. Fourth are the density, viscosity, Poisson’s ratio under operating conditions, cut-off pressure, and so on.