The valve is in the fluid system, is used to control the direction of the fluid, pressure, flow of the device is to make the piping and equipment within the medium (liquid, gas, powder) flow or stop and can control the flow of the device, the valve is an important control in fluid delivery system components.

Preparation before operation

Read the instructions carefully before operating the valve. Be sure to clear the gas flow before operation. Check valve opening and closing marks. Check the valve appearance to see whether the valve is damp, if there is moisture dry treatment; If any other problem is found, it should be handled in a timely manner without fault operation. If the electric valve is stopped for more than 3 months, the clutch should be checked before starting. After confirming the handle in the manual position, the insulation, steering and electrical wiring of the motor should be checked.

Correct operation of manual valve

Manual valve is the most widely used valve, its handwheel or handle, is designed according to ordinary manpower, considering the strength of the sealing cover and the necessary closing force. So you can't use a long lever or a long plate hand to move the board. Some people are used to using plate hand, should pay close attention to, when opening valve, should exert oneself firmly and steadily, avoid to exert oneself too hard, cause to open and close valve, force should be stable, cannot impact. Some parts of high pressure valves with impact opening and closing have considered the impact force and general valves can not wait.

When the valve is fully open, the handwheel should be reversed a little, so that the thread between tightly, so as not to loose damage. For open stem valves, remember the stem position when fully open and fully closed to avoid hitting the upper dead point when fully open. It is also convenient to check whether the complete closure is normal. If the valve handle falls off, or the valve core seal is embedded between larger sundries, the valve stem position when full closure is about to change. Damage to valve seal or handwheel.

Valve opening mark: when the groove on the top of ball valve, butterfly valve and cock valve stem is parallel to the channel, it indicates that the valve is in the fully open position. When the stem rotates 90 to the left or right. When, the groove is perpendicular to the channel, indicating that the valve is in the fully closed position. Some ball valves, butterfly valves, and plug valves open with wrench and channel horizontal behavior, vertical closed. The operation of three-way and four-way valves shall follow the mark of opening, closing and reversing. Remove the handle after operation.

Correct operation of the relief valve

The safety valve passed the test and fixed pressure before installation. Run safety valve for a long time, the operator should pay attention to check the safety valve, check, from the relief valve outlet, check the seal of the relief valve, safety valve lever up with wrench, open a period of time, between drainage in addition to dirt, check the flexibility of the relief valve.

Correct operation of trap

Hydrophobic valve is easy to be fouled by water and other debris blocked valves. When enabled, first open the flush valve, flush the pipe. If a bypass pipe is provided, the bypass valve may be opened for a brief flush. The drain valve without flushing pipe and by-pass pipe can be removed, and the drain valve can be opened after cutting off and washing. Then the shut-off valve can be closed, and the shut-off valve can be installed, and then the shut-off valve can be opened to enable the shut-off valve.

Correct operation of pressure relief valve

Before starting the pressure relief valve, open the bypass valve or flushing valve, clean the pipe dirt, after the pipe is cleaned, close the bypass valve and flushing valve, and then enable the pressure relief valve. Before some of the steam pressure reducing valve, trap needs to open, then slightly open the cut-off valve after pressure reducing valve, finally the pressure reducing valve before the cut-off valve open, watch the pressure reducing valve and pressure gauge, adjust the relief valve adjusting screw, the valve after pressure to the expected value, then slowly open the shut-off valve after pressure reducing valve, valve after pressure correction, until satisfied. Fix the adjusting screw and cover the protective cap.

Such as

Fruit malfunction or to repair the relief valve, should slowly open the bypass valve, close the valve at the same time before cut-off valve, manual roughly adjust the by-pass valve, the pressure reducing valve after pressure basically stable at a predetermined value, then close the pressure reducing valve replacement or repair, then back to normal.

Correct operation of check valve

In order to avoid the check valve is closed instantly formed high impact, the valve must be closed quickly, thus to prevent the reverse form great speed, the backflow speed when the valve is closed when all of a sudden, is the reason why the impact pressure. Therefore, the closing speed of the valve should match the attenuation speed of the downstream medium correctly.

If the velocity of the downstream medium varies widely, the minimum velocity is not sufficient to force the closure to stop stably. In this case, the movement of the closing member can be suppressed by a damper within a certain range of its action stroke. The quick vibration of the closing parts will cause the valve moving parts to wear out too fast, leading to premature valve failure. If the medium is a pulsating flow, the quick vibration of the closing member is also caused by extreme dielectric disturbance. In any case, the check valve should be placed where the medium disturbance is least.