Molecular formula :
nature : the lever and heavy hammer to force transmitted to the valve was closed as a safety valve, valve seat. Similar to the angle-cut-off valve, pressure valve disk media at the bottom, when the medium pressure exceeding a specified value, the valve will be set up in the top to vent to the outside world, changing the weight of a heavy hammer and position of the valve that is set to change the clamping force can be a safety valve regulating the work of pressure. Heavy automatic prevent mobile devices and beyond the limit leveraged derivative planes. Applied to high temperature, but not compact structure.
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