A. Persistence of the selection of the containment valve
The conditioning valve is an actuator in the self-control fine crushing, and its utilization quality indirectly echoes the fine crushing quality. As a terminal element in the process of containment, people are more familiar with its persistence than before. Regarding the quality of the use of the conditioning valve, in addition to the quality of the product and whether the user can accurately install, coax, and maintain it, it is accurately calculated and selected. Due to miscalculation of the selection, the components are switched on and off, and some of them cannot be put into use. Therefore, the users and the planning staff should be familiar with the persistence of the valve at the scene, and sufficient attention must be paid to the selection of the regulating valve. .
B. Principles for the selection of the containment valve
1. Comply with the technological premises and decide on the appropriate layout mode and quality materials.
Second, in accordance with the characteristics of the process tools, determined to contain the flow characteristics of the valve.
3. In accordance with the process and utilization parameters, determine the appropriate size of the check valve diameter.
4. Comply with the requirements of the craftsmanship, and decide to place the needed help.
5. Partially determined to implement the agency. The corresponding speed of the actuator should be able to compliment the process
The request for the time of the containment stroke: The selected containment valve actuator should be able to meet the requirements of the valve stroke and process for the level of leakage. In some occasions, such as the selection of a pressure control valve (sweeping the vent valve), the improper amplification of the possible pressure difference should be considered in practice, that is, the actuator can be requested to supply a larger inductive force. Otherwise, maybe when there is an abnormal environment in the process, the actual pressure difference of the control valve is relatively large, which will cause the killing that cannot be closed or opened.
Second, the accessories of the containment valve
In the production process, the control valve makes all kinds of extraordinary requests for the valve. Therefore, the control valve must be equipped with various subordinate devices (referred to as accessories) to satisfy the needs of the production process. The accessories of the containment valve are sweeping:
1. The valve positioner is used to improve the mission characteristics of the control valve regulation and to complete the positive position.
2. The valve position switch indicates the mission position of the upper and lower limit travel of the valve.
3. Pneumatic retaining valve When the air source of the restraining valve fails, the connecting valve is in the position of opening before the air source fails.
4. The solenoid valve completes the electromagnetic switching of the gas circuit to ensure that the valve is in the desired safe opening position when the power supply fails.
5. The handwheel mechanism can switch to the manual orally to use the valve when the pinning device fails.
6. The pneumatic relay accelerates the method of the actuator and reduces the transmission time.
7. The air filter pressure reducer is used to purify the air source and adjust the air pressure.
8. The gas storage tank ensures that when the gas source fails, the springless cylinder piston actuator may restrict the valve to the fail-safe position. Its size depends on the size of the cylinder, the requirements of the valve method and the mission of the valve.
In short, the sense of accessories is to make the holding of the check valve more perfect, more biased, and more complete.
3. Maintenance of the containment valve
The containment valve has the characteristics of complicated layout and reliable method, but because it indirectly constitutes a force with the process medium, it indirectly affects the quality of the fines and the environmental infection, so the frequent maintenance and current examinations must be terminated for the containment valve, which is extremely harmful to the premises. In dying occasions, the mission of training should be emphasized. Key inspection sites
1. The inner wall of the valve
For the containment valve that is used in the occasion of high pressure difference and winning medium, the inner wall of the valve body and the diaphragm of the diaphragm valve are often attacked and won by the medium. It is necessary to focus on the pressure-resistant and corrosion-resistant environment.
Second, the valve seat
During the check valve's mission, the threaded inner surface for fixing the valve seat is easy to get loose due to the infiltration of the medium, and the valve seat should be stabilized during inspection. For valves with high pressure differences, check whether the sealing surface of the valve seat can be damaged.
3. Spool
The spool is a movable part in the conditioning mission. It is most dying to be washed by the medium and winning. During the exam, you must work hard to check whether all the spools can be won and worn. Very much, the wear of the spool is more and more dying under the environment of high pressure difference ( Due to cavitation), it should be stabilized. When the spool is damaged and dying, the adjustment should be terminated. In addition, the stable valve stem should be similar, or the connection with the spool should be loose.
4. Diaphragm "O" ring and external gasket. The diaphragm and "O"-shaped gasket in the containment valve should be inspected for aging and cracking.
5. Sealing packing
The stable PTFE packing and sealing lubricating grease should be aging, and the mating surface should be damaged, and should be adjusted when necessary.
