The installation tips of gate valves

Precautions for gate valve operation:
The basic operation of the gate valve:
1. The gate valve with bypass should be opened before opening the bypass valve (to balance the differential pressure in and out and reduce the opening torque).

2. When operating, the human body should not be facing the top of the valve stem to prevent the stem from being pressurized and ejected.

3. Switching operation should be smooth, force to be uniform, the use of impact is strictly prohibited, the general situation can be operated by hand, avoid the use of force lever to operate the new valve.

4. Handwheel (handle) strength is designed to operate the required torque value as a reference basis, so do not handwheel (handle) as an operating pedal and arbitrary growth or lengthening lever, or a wrench to increase the torque excessively, not to use ropes and other roles in the handwheel (handle), and then a crane or pulley to operate or lift the valve.

5. gate valve with handwheel or handle, turn the handwheel clockwise to close, counterclockwise to open. When the valve is fully open, the handwheel should be turned back 1 to 2 turns in the opposite direction. The operation of the gate valve with other actuators should strictly follow the product instructions.

6. Under the high pressure difference, the gate is half open and half closed state easy to damage the gate, so the gate valve can not be used for throttling or regulation, must be completely open or completely closed at one time.

 

Gate valve without stopping to replace the packing:

1. Preparation work

①Material preparation: packing with the size of the valve cover packing letter specifications, the appropriate amount of leak detection fluid and cotton yarn.

② Tools preparation: two wrenches, one scissors, two screw spinners (100mm), one brush (25mm) in line with the packing gland nut size.

2. Operation steps

① Use the wrench to loosen the packing gland nut slowly and evenly and observe the pressure leakage in the stuffing box.

② Determine that the pressure leakage is stable and no longer increasing, remove the packing gland nut and lift the packing gland to observe the leakage and the original packing up in the stuffing box.

③When the pressure leakage in the stuffing box is stable and decreasing, and the packing is moving up slightly, then proceed to the following steps.

④Cut the prepared packing into a short section with the length matching the circumference of the stuffing box and the 45° slant at both ends.

⑤Take a section of the cut packing and press it into the stuffing box around the valve stem, if it is not full, continue to add the second one, pay attention to the position of the two interfaces should be staggered about 120°, until it is full.

⑥Cover the packing gland, screw on the packing gland nut, tighten the nut symmetrically and evenly with a wrench, and press the packing gland moderately.

(7) Check whether the packing is leaking with the leak detection tool, if there is leakage, tighten the gland nut appropriately to further compress the packing until it does not leak.

Technical requirements and precautions

1. Make sure the gate valve is in full closed position before packing, the human body is strictly prohibited to face the valve stem when operating (for valves with upper sealing structure, the valve can be opened to full open position).

2. Loosen the packing gland nut slowly, force evenly, pay close attention to observe the pressure leakage, if the amount of leakage found when loosening the nut is too large, should immediately tighten the packing gland nut, stop packing operation.

3. The end bevel of each packing section is 30°~45°, the length should be just one circle around the valve stem, when pressed into the stuffing box, the two ends bevel should be flat butt, the interface of the upper and lower two packing should be staggered about 90°~120°.

4. Tighten the packing gland nut, should be symmetrical, uniform force, the gland should meet the degree of compression of the packing no leakage, the valve stem up and down movement flexible.

5. The packing should not be too full, not more than 3/4 of the depth of the stuffing box is appropriate after tightening.

Complete solutions for Industrial valves.