For ammonia use ball valves, fire and static electricity protection are required, as well as copper-free construction; is pressure relief in an intermediate chamber necessary?
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Ball valve for ammonia, with medium being liquid ammonia; floating ball valve AQ41F-16P. Fire and static protection are required, as well as copper prohibition; is pressure relief in a middle chamber needed? Should the vent for the middle chamber be provided with an opening at the lower end of the valve shaft or at the inlet end?
When the ball valve is closed, if the medium trapped in the valve chamber between the two seat surfaces experiences an increase in temperature, the pressure there will rise. To avoid danger, it is necessary to release the pressure in the valve chamber once a certain pressure level is reached (API6D specifies this as 1.33 times the operating pressure). Internal pressure relief refers to the phenomenon where, once the upstream valve seat of a ball valve (usually of the piston type) reaches a specified pressure value, it is pushed away from the valve ball by the pressure of the medium, allowing the high-pressure medium to be released upstream; thereafter, the valve seat returns to its original position automatically.