Valve installation and flange welding

1, the installation of the valve

The valve installation is easy to use with the lifting ring. When installing with the chain, pay attention to the protective measures for the outer coating of the valve. When the valve has a bracket or transmission mechanism, the sling should be fixed on the valve sling, and the sling should not be placed on the transmission mechanism; the sling or hoisting chain cannot squeeze the external parts of the valve and its extension rod to avoid damage to the valve actuator. , causing the valve to be unable to switch or switch difficult.

2, the welding of the valve

(1) After the valve is in place, the valve should be placed in the fully open position during the preheating and welding of the valve. Otherwise, during the welding process, the ball of the ball valve and the gate of the gate valve will be stained with slag. These attached slag will scratch the seat seal, causing leakage inside the valve and causing valve failure in severe cases.

(2) The valves must be supported on their respective bases or separately supported.

(3) After the valve is welded, if the valve needs to be rotated, the grease should be filled with a manual grease gun.

(4) Confirm that the drain outlet and the discharge port are closed.

(5) The general ball valve installation has no directionality, but attention should be paid to the position of the operation side. Some ball valves have directionality when installed, and must be installed according to the arrow mark on the valve body, and cannot be reverse mounted. For example, the inlet and outlet sides of some of the ball valves of the crude oil and product oil stations of the Western Pipeline are in the form of two valve seat seals, one end adopts a double piston effect valve seat, and the other end adopts a self-venting sealing valve seat. After the application, the valve will automatically release pressure and a pipeline accident will occur.

3. Requirements after valve welding

(1) Before the valve is pressure tested after welding, the grease should be injected to ensure that the sealing surface of the valve is filled with grease, and the impurities adhering to the sealing surface of the valve seat are discharged with grease.

(2) Check the condition of the valve to ensure that the external joints are locked and there is no looseness; confirm that the drain outlet and the discharge port are in a locked state to prepare for the pressure test.

(3) Operate the valve according to the pressure test scheme so that the valve is in the specified position. -Sanjing Valve Technology Department provides