The function of the TXZTQ automatic vent valve is that during the lifting or lowering of the floating roof to the bottom plate of the tank, the vent valve will automatically close or open to allow the gas below the floating body to be discharged or replenished. This is to avoid excessive pressure or vacuum in the gas phase space below the floating roof, which could damage the floating roof or other accessories. Under normal circumstances, this vent valve is automatically closed, which can prevent the evaporation loss of the oil product.