Tips on the selection of the hottest low temperatu

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Tips for the selection of low-temperature valves

generally speaking, valves that can be used at temperatures below -101 ℃ are low-temperature valves. Low temperature is also a kind of harsh working conditions. For the control valve used in low temperature working conditions, like the high temperature valve, many factors need to be considered, the most important of which is the sealing of materials and packing

I. low temperature materials

under the temperature below -180 ℃, there is no oil leakage and other phenomena in plastic and elastic materials, and the parts of materials are not suitable. In this temperature range, we have expanded this series. The packing and valve core sealing elements need special consideration, and the soft sealing method can no longer be used (the soft seal will harden and lack flexibility, and cannot provide good cutting capacity). Under this temperature condition, special elastic materials should be used. When the standard tensile specimen is in the tensile state, the extensometer or strain gauge should be installed on it, and special load should be provided to obtain good cutting effect

II. Problems that should be paid attention to in packing sealing

in low temperature occasions, the water in the atmosphere will condense when the temperature is lower than the freezing point, forming a layer of frost. If frost forms on the surface of the valve stem, when the valve stem is driven up and down by the actuator, this layer of frost may be pulled into the packing and cause tearing, thereby damaging the seal. Therefore, an elongated upper bonnet should be used to keep the stuffing box area of the control valve away from the low temperature area to avoid frost forming in the valve stem and stuffing box area

low temperature double seat regulating valve

III. typical low temperature regulating valve

in low temperature occasions, the more suitable valve types mainly include single seat valve, double seat valve, angle valve and small flow valve. On the basis of these valve structures, attention should also be paid to the problems of low temperature application. It can become a low temperature valve with a special extended upper bonnet. The length of the extended upper bonnet and the maximum range (v/div) of the oscilloscope depend on the temperature and heat insulation requirements of the application. The lower the temperature of the application, the longer the extended upper bonnet

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