The plunger valve is composed of valve body, valve cover, valve stem, plunger, hole frame, sealing ring, hand wheel and other parts. When the handwheel rotates, the valve stem drives the plunger to move up and down in the middle of the hole frame to complete the valve opening and closing function. Interference fit is adopted between the plunger and the sealing ring in the valve. By adjusting the flange bolt of the gland, the lateral force generated by the compression of the sealing ring is sealed with the hole surface of the valve body and the outer circle of the plunger, so as to ensure the sealing of the valve, eliminate internal and external leakage, and the opening torque of the valve is small, and the valve can be opened and closed quickly. Compared with the globe valve, the plunger valve has a long life and less effort to operate. However, the adjustment stroke is longer than the stop valve, so the throttle control is more difficult than the stop valve. Where there are clear requirements for regulation, neither is suitable.