Dead weight safety valve consists of a large vertical steel pipe with a flange at the lower end for fitting it on the boiler shell. Valve seat is carefully and rigidly fixed at the top of the pipe. The valve actually is resting on this valve seat. This valve supports a large weight carrier where dead weight rings are kept and enclosed by the cover. Thus the contribution to the total load comes from the weight of the carrier, the dead weight rings, the cover and the valve. When the force due to steam pressure is less than the total load of the valve, the steam will reside within the valve. When the force due to the steam pressure is exactly equal to the total load of the valve, it will be in the position of just blowing. When the force due to steam pressure exceeds the total load of the valve, it lifts and the steam escapes through the discharge pipe. When pressure drops and attains normal value, valve returns to its initial position.
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