U41S flange plunger valve is composed of valve body, bonnet, valve stem, plunger, guide sleeve, sealing ring, handwheel and other parts (as shown in the figure). When the handwheel rotates, the valve rod drives the plunger to move up and down in the middle of the guide sleeve to open and close the valve. The interference fit is used between the plunger and the seal ring in the valve. By adjusting the flange bolts in the gland, the seal ring compresses the lateral force generated by the product and seals the middle hole surface of the valve body and the outer circle of the column plug, so as to ensure the sealing of the valve, eliminate internal leakage, and achieve rapid opening and closing of the valve with small opening torque. Since the sealing ring adopts non-toxic new sealing material with strong resilience and high wear resistance, it can withstand long-term high temperature and pressure without losing elasticity, so the sealing performance is reliable and durable.