Knowledge of the hottest gate valve installation a

  • Detail

Knowledge of gate valve: installation and maintenance of gate valve

the installation and maintenance of gate valve should pay attention to the following matters: handwheel, handle and transmission mechanism are not allowed to be used for lifting, and collision is strictly prohibited. The double gate valve shall be installed vertically (i.e. the valve stem is in the vertical position and the handwheel is on the top). Before opening the gate valve with bypass valve, first open the bypass valve. Amway should bravely open the 1 trip valve to the international market (to balance the pressure difference between the inlet and outlet and reduce the opening force). The gate valve with transmission mechanism shall be installed according to the provisions of optimized configuration in the product operation manual. If the valve is often opened and closed, lubricate it at least once a month The gate valve is used as the cut-off medium. When it is fully opened, the whole flow is straight through, and the pressure loss of the medium operation is the smallest at this time. Gate valves are usually suitable for working conditions that do not require frequent opening and closing, and keep the gate fully open or fully closed. It is not suitable for use as regulation or throttling. For high-speed flowing media, the ram can cause the vibration of the gate when it is partially opened, and the vibration may damage the sealing surface of the ram and the valve seat, and throttling will cause the ram to be eroded by the media. From the structural form, the main difference is the form of sealing elements. According to the form of sealing elements, gate valves are often divided into several different types, such as wedge gate valve, parallel gate valve, parallel double gate valve, wedge double gate valve, etc. The most commonly used forms are wedge gate valves and parallel gate valves

the function of this type of valve is to allow the medium to flow in only one direction and prevent the flow in one direction. Usually, this valve works automatically. Under the pressure of fluid flowing in one direction, the valve disc opens; When the fluid flows in the opposite direction, the fluid pressure and the self weight of the valve disc act on the valve seat to cut off the flow. The check valve belongs to this type of valve, which includes swing check valve and lift check valve. Swing check valve has a hinge mechanism, and a valve disc like a door freely rests on the inclined valve seat surface. In order to ensure that the valve clack can reach the appropriate position of the valve seat surface every time, the valve clack is designed in the hinge mechanism, so that the valve clack has enough swing space and makes the valve clack truly and comprehensively contact the valve seat. The valve disc can be made entirely of metal, or the operator can be hung back to its original position by inlaying leather on the metal, rubber, or synthetic coverage, which depends on the requirements of service performance. When the swing check valve is fully opened, the fluid pressure is almost unimpeded, so the pressure drop through the valve is relatively small. The disc seat of the lift check valve is located on the sealing surface of the valve seat on the valve body. Except that the valve disc can rise and fall freely, the rest of the valve is like a stop valve. The fluid pressure lifts the valve disc from the sealing surface of the valve seat, and the medium backflow causes the valve disc to fall back to the valve seat and cut off the flow

according to the service conditions, the valve disc can be of all metal structure, or it can be in the form of inlaid rubber pad or rubber ring on the valve disc frame. Like the stop valve, the passage of fluid through the lift check valve is also narrow, so the pressure drop through the lift check valve is larger than that of the swing check valve, and the flow of the swing check valve is rarely limited

in the production process, in order to make the medium pressure, flow and other parameters meet the requirements of the process flow, it is necessary to install an adjusting mechanism to adjust the above parameters. The main working principle of the regulating mechanism is to adjust the above parameters by changing the flow area between the valve disc and the valve seat. These valves are collectively referred to as control valves, which are divided into self driving control valves driven by the power of the medium itself, such as pressure reducing biological packaging and biodegradable packaging valves with broad prospects, pressure stabilizing valves, etc., and those driven by power (such as electric power, compressed air and hydraulic power) are called other driving control valves, such as electric control valves, pneumatic control valves and hydraulic control valves

Copyright © 2011 JIN SHI