更新時間：2018.07.20

Medium corrosion, poor manufacturing quality, improper operation, etc., will lead to the closure of the joint damage and fall off. This is a dangerous malfunction that prevents the valve from opening and the valve from closing properly. Taking gate valve as an example, this paper introduces the emergency treatment after gate plate falls off. 1. The method of opening the valve by the top rod can be adopted when the gate plate needs to be opened after it falls off. This method can also eliminate some foreign matter between the gate and the seat. On the corresponding valve body at the tip (small head) of the middle chamber gate plate of the gate valve, weld a small valve with packing device, open the valve completely, drill the valve to the middle chamber gate plate, pull out the drill bit, close the small valve, install the top rod and stuffing, and open the valve, and open the top of the top bar to open the closing parts. As shown in the figure below: before opening the gate, the stem should be adjusted to a high position in advance to avoid the gate against the stem. 2, a handstand open valve According to the 180 ° upward transposition stem stem prolapse, the cover is to take the gravity of ram fall into, automatically open the valve. Therefore, the method should loosen the gasket at both ends of the valve, more or less will produce leakage phenomenon. Therefore, this method is only applicable to non-toxic, non-combustible, non-explosive, low temperature and low pressure working conditions. This method is best for the convex and concave surface, tenon groove surface, trapezoid groove and other types of static seal, avoid plane type static seal as far as possible. First of all, two sets of two semicircle sleeve should be made according to the flange size. The gap between them should be small. Card installed, remove flange screw, tied to quickly adjust the valve 180 °. Be careful not to push the gasket out of the static seal position, affecting the seal. Then aim the screw hole and tighten the bolts until they are tight. This time plate will automatically fall off the seat and the valve will open. If the ram does not fall, copper rod can be used to knock the valve body, so that the ram will fall after vibration. In order not to push the stem against the gate, the stem should be unscrewed to the upper dead point. If the gate is threaded connections at two ends and union connection, generally only need to exchange 180 ° position the valve is ok. If it is difficult to analyze which side the tight end is, adjust the live joint or trim the thread properly. After opening the valve upside down, if the leakage at the two ends of the gaskets cannot be blocked, the leak sealing method can be adopted. The flange joint can be prefabricated with the injection hole on the card sleeve in advance, and the leakage can be stopped by the method of high-pressure glue injection. 3. After the pressure bonding closing parts (gate plates) of the closing parts fall off, the valve may be very difficult because there is no pressure applied on the gate plates. At this time can use the strong pressure injection method or the use of the plug on the valve to infiltrate into the valve. 4. When the valve is in the closed state or has minor leakage after the valve cover pressure repair gate falls off, adhesive is used to fix the gate plate (which is self-locking under low pressure), plug the leakage, and then open the cover to repair the connection between the gate plate and the stem. This method is suitable for gate valves that cannot be stopped for pressure relief repair and are often opened and closed. 5. After the valve is blocked, dredge semi-liquid medium and easy to crystallize and solidify medium, which is easy to block the valve passage, resulting in the equipment and pipelines not working normally. Remove the pipe at the outlet of the valve, remove the plug at the outlet, install the special packing device and drill, open the valve, and drill through the plug at the population end of the valve. Then exit the bit, close the valve, remove the stuffing device and the bit, and restore the original pipeline. Finally open the valve and wash away the sediment. This method is only applicable to gate valve, ball valve, plug valve and other straight - way valves.