Gate valve pressure test strength test method and cut-off valve. Tightness test valve in two ways. ① gate open so that the internal valve pressure rises to a predetermined value; then close the gate, immediately remove the valve, check whether the gate on both sides to seal a leak inside the valve cover or plug injection test media directly to the specified value Check gate seals on both sides. The above method is called intermediate pressure test. This method should not be in the nominal diameter of the valve DN32mm do the following seal test. ② Another method is to open the gate, so that the valve test pressure was raised to a predetermined value; then closing plate, open end of the blind, check the sealing surface for leaks. And then fell down, make more than repeat the test to pass up. Pneumatic valve packing and gasket sealing at the test should be carried out before the gate sealing tests. Stem gate valve and the dark bar gate valve according to what is the difference stem structure can be divided into: a clear shot valve: the valve stem nut on the valve cover or bracket, valves, opening and closing the shutter, achieved by rotating the stem nut the valve stem down. This structure of the valve stem lubrication favorable, Shanghai and Shanghai Valve Manufacturing Co., Ltd., the closing level of obvious, so widely used. 2 dark bar valve: the valve stem nut body, direct contact with the media. When the opening and closing gate with a rotary valve stem to achieve. The advantage of this structure are: the height of gate is always kept constant, so installation space is small, Suzhou Watts Valve Co., Ltd., is suitable for large diameter or restricted valve installation space. Such structure should be equipped with open and close indicator to indicate the degree of opening and closing. The disadvantage of this structure are: the stem threads not only can not be lubricated, but also directly accept the medium erosion, easy to damage. Tianjin Tanggu valve limited liability company | Ming Kong valve (Online) | valve provided by the Dongguan Science and Technology Co., Ltd., the Hong Kong valve. Valve Co., Ltd., Dongguan Ming Kong (www.gdmgfm.com) is Dongguan, butterfly leaders, over the years, the company implement the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Ming Kong valve leadership with the staff warmly welcome all inquiries negotiations to create a better valve out of Hong Kong in the future.