Selection of Valve Electric Actuator Models
Sep 26,2022Read More
The quality of the valve installation directly affects the using performance, because we must pay attention to the direction and position of the valve installation. During the installation, we must be careful not to touch the valve made of brittle materials, and do a good job in various protective measures and a series of work. Next, MSTN International Technologies Company will introduce the problems and details that should be paid attention to when installing valves.
Many valves are directional, such as globe valve, butterfly valve, pressure reducing valve, check valve, etc. If it is reversed, it will affect the use effect and service life, or it will not work at all, or even cause danger; Ordinary valves have direction marks on the valve body; Otherwise, it should be correctly identified according to the working principle of the valve; The cavity of the stop valve is asymmetric.
The fluid should pass through the valve port from bottom to top, so that the fluid resistance is small, the opening is labor-saving, and the medium does not press the packing, which is convenient for maintenance. This is also the reason why the stop valve cannot be reversed. Other valves also have their own characteristics.
The installation position of the valve is easy to operate: even if the installation is temporarily difficult, the long-term work of the operator should be considered;
The handwheel of the valve is flush with the hood, which makes the valve easier to open and close; The handwheel for the valve should face upwards and cannot be tilted to avoid wrong operation.
Wall-mounted machine valves and equipment should also leave standing space for operators. Avoid working in the air, especially acid and alkali, toxic media, or it will be very unsafe.
When installing the wedge, don't turn it upside down, otherwise the medium will stay in the gap of the bonnet for a long time, which will easily corrode the valve stem. It is taboo. At the same time, it is very inconvenient to change the gasket.
The gate valve with exposed valve stem shall not be installed underground, otherwise the exposed valve stem will be corroded by moisture.
When installing the lift check valve, make sure that the valve cover is vertical, so that it can be lifted flexibly.
For swing check valves, the clevis pin with head should be in a horizontal position during installation, so that it can swing flexibly.
The pressure reducing valve shall be installed vertically on the horizontal pipeline, and shall not tilt in all directions.
Some industrial valves also need external protection, that is, heat and cold preservation. Sometimes a hot steam pipe is added to the insulation layer. The type of valve that needs to be kept hot or cold depends on the production requirements.
In principle, if the temperature of the medium in the valve decreases too much, it will affect the production efficiency or freeze the valve, so it should be kept warm or even mixed with heat.
The exposed valve is not conducive to production. It may cause frosting and other undesirable phenomena, and need to be refrigerated. Thermal insulation materials include asbestos, slag wool, glass wool, perlite, diatomite, vermiculite, etc. Cold insulation materials include cork, perlite, foam, plastic, etc.
For the valves in stock, some packings are not good enough, and some do not match the used media, so the gaskets need to be replaced.
Manufacturers of valves can't consider using several different types of media. Packing boxes are always filled with ordinary packing, but the packing should be compatible with the media when used.
When replacing the gasket, the seam of each circle should be 45 degrees, and the circle should be opened by 180 degrees. The height of packing should take into account the space for the gland to continue compaction. At present, the stuffing chamber at the bottom of stuffing box should have enough depth.
This depth can usually be 10-20% of the total depth. For demanding valves, the joint angle is 30 degrees. The seams between the circles are staggered by 120 degrees.
In addition to the above packing, three rubber O-rings can be installed. According to the specific conditions, stratum fillers such as laminated polytetrafluoroethylene rings and bowl-shaped nylon rings are used.
Adding a layer of PTFE tape to the ordinary asbestos package can improve the sealing effect and reduce the electrochemical corrosion of the valve stem.
The problems and details that should be paid attention to when installing valves are introduced above. When operating under high pressure, turn the valve stem at the same time to keep the surroundings even and prevent excessive exertion. Tighten the bottle cap evenly and do not tilt it.
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