What are the functions of the pipeline valve?
how to install?
Common logo what does it mean?
Failure, how to repair? Pipeline valve 4 kinds of functions
First, cut off and release media
This is the most basic valve function, usually the choice of flow-through valve, the flow resistance is small.
Closed-down valve (globe valve, piston valve) because of its tortuous flow, flow resistance than other valves, it is less choice. In the case of allowing higher flow resistance, the choice of closed valve.
Second, control flow
Usually choose to adjust the flow of the valve as a control flow. Closed-down valves, such as stop valves, are suitable for this purpose because their seat size is proportional to the travel of the closure.
Rotary valves (plug valves, butterfly valves, ball valves) and flexible valve bodies (pinch valves, diaphragm valves) can also be used for throttling control, but usually only for a limited range of valve diameters.
Gate valve is a disc-shaped gate of the circular valve seat to make cross-sectional movement, it only close to the closed position, in order to better control the flow, it is not usually used for flow control.
Third, divert to divert
Depending on the need for diverting, the valve can have three or more passages. Plug valves and ball valves are more suitable for this purpose, therefore, most of the valves used for diverting shunts select one of these types of valves.
However, in some cases, other types of valves, as long as the two or more valves properly connected to each other, but also for diverting diverting.
Fourth, the medium with suspended particles
When the medium with suspended particles, the most suitable for the use of its closure along the sealing surface sliding wipe with a valve.
If the closure is vertical to the seat back and forth, the particles may be clamped, so this valve is only suitable for basic cleaning media unless the seal face material allows for embedment of particles. Ball valve and plug valve in the opening and closing process on the sealing surface are wiping effect, it is suitable for use in the medium with suspended particles. Pipeline valve installation problems
First, check before installation
1. Carefully check the valve type, the specifications are in line with the drawings requirements.
2. Check the valve stem and flap open is flexible, there is no stuck and skew phenomenon.
3. Check the valve for damage, threaded thread is correct and intact.
4. Check the valve seat and the valve body is solid, valve and valve seat, valve cover and valve body, the valve stem and the valve of the link.
5. Check valve packing, packing and fasteners (bolts) are suitable for the nature of the working medium requirements.
6. The old or shelved longer decompression valve should be removed, dust, sand and other debris to be cleaned with water.
7. Clear the port cover, check the seal, the valve must be closed tightly.
Second, the general provisions of the installation
1. Valve installation position should not hinder the operation of equipment, pipes and valve body, dismantling and maintenance, taking into account the aesthetic appearance of the assembly.
2. Horizontal pipe valve, stem upward installation, or tilt a certain angle installation, not the hand wheel down to install. High-altitude pipeline valves, stems and hand wheels can be installed horizontally, with vertical low chain remote control valve opening and closing.
3. Arrangement of symmetry, neat and beautiful; legislation on the valve, the process allows the premise, the valve handle to chest height is most suitable for operation, generally 1.0-1.2m from the ground is appropriate, and the stem must be along the operator Direction installation.
4. Side by side on the pipe valve, the center line of the same height, and the clear distance between the hand wheel is not less than 100mm; side by side horizontal pipe valve should be staggered installation, in order to reduce pipe spacing.
5. In the pumps, heat exchangers and other equipment to install heavier valves, valves should be set brackets; frequent operation and installed in the valve from the operating surface more than 1.8m, should be set up a fixed operating platform.
6. There is an arrow mark on the body of the valve, the direction of the arrow is the flow direction of the medium. When installing the valve, care should be taken that the arrows point in the same direction as the media in the pipe.
7. Flange valve installation, should ensure that the flange face parallel to each other and concentric, shall not use double shims.
8. When installing a threaded valve, a threaded valve should be fitted with a live connection for ease of removal. Living connections should be set to take over the convenience of maintenance, usually through the valve after the first flow through the living connection.
Third, the installation precautions
1. The valve body material is made of cast iron, brittle, it is not subject to heavy impact.
2. When handling the valve, do not allow throwing; lifting, lifting the valve, the rope should be tied to the body, not to tether hand wheel, stem and flange bolt hole.
3. Valve should be installed in the operation, maintenance and repair the most convenient place, is strictly prohibited buried in the ground. Buried and ditch within the pipeline valves should be located in the inspection room, in order to facilitate the valve opening and closing and regulation.
4 should ensure complete and non-destructive thread, and the thread wrapped in Ma, wipe oil or PTFE wrapped with raw materials, spin buckle, the need to use a wrench screwed into the hexagonal valve body at one end.
5. When installing the flange valve, pay attention to tighten the connecting bolt along the diagonal direction, and force it evenly when it is twisted to prevent the gasket from running off or causing the valve body to be deformed and damaged.
6. The valve should be kept closed during installation. On the wall closer to the threaded valve, the installation often need to remove the valve stem and hand wheel valve, can be screwed. When disassembling, please turn the handwheel to keep the valve open and then disassemble. Pipeline valve 6 kinds of commonly used methods of installation
First, the valve
Also known as the gate valve, is the use of gate to control the opening and closing of the valve, by changing the cross-section to regulate the pipeline flow and opening and closing pipeline. Gate valves are mostly used for the fluid medium to be fully or fully closed operation of the pipeline.
Gate valve installation generally non-directional requirements, but not flip.
Second, stop valve
Is to use the valve to control the opening and closing of the valve. By changing the disc and valve seat clearance, that is, the size of the channel section to adjust the media flow or cut off the media access. Shut-off valve must be installed to pay attention to the flow of fluid.
The principle that must be followed when installing the globe valve is that the fluid in the pipe passes through the valve hole from bottom to top, commonly known as "low entry and high exit".
Third, check valve
Check valve, also known as check valve, check valve, is a valve before and after the pressure difference between the opening and closing of the valve automatically, its role is to make the media only in one direction of flow, and prevent the media back to reverse flow.
Check valve according to their different structures, there are lift, swing-type and butterfly-type clip. Lift check valve there is horizontal and vertical points.
When installing the check valve, should also pay attention to the flow of medium, can not be installed anti.
Fourth, the valve
1. Vertical installation of the valve group, generally along the wall set at a suitable height from the ground; horizontal installation of the valve group, usually installed on a permanent operating platform.
2. Application of steel in the two control valves (commonly used in the globe valve) outside the loading wall, constitute the bracket, bypass pipe stuck in the bracket, leveling and leveling.
3. The pressure relief valve should be installed upright on the horizontal pipe, not inclined, the arrow on the valve body should point to the direction of flow of the medium, shall not be installed.
4. Both sides of the globe valve should be installed and high and low pressure gauges, in order to observe the pressure changes before and after the valve. Pressure reducing valve after the pipe diameter should be larger than the inlet diameter of the valve 2 # -3 #, and installed on the bypass pipe for inspection.
5. Membrane valve pressure equalizer, should be connected to the low-pressure pipe. Low-pressure pipe, safety valve should be set to ensure the safe operation of the system.
6. For steam decompression, to set the drain. Demands on the degree of purification of the pipeline system, set the filter in front of the valve.
7. After the installation of pressure reducing valve assembly, the pressure reducing valve and safety valve shall be pressure tested, rinsed and adjusted according to the design requirements, and the adjusted sign shall be made.
8. When depressurizing the valve, close the pressure reducer inlet valve and open the flush valve for flushing.
Fifth, traps
1. Before and after the cut-off valve should be set (cut-off valve), trap and the former cut-off valve should be set between the filter to prevent dirt in the condensate clogging traps.
2. Traps and after the cut-off valve should be set between the inspection tube, used to check the trap work is normal, such as open a large number of steam check tube, then the trap is broken, need maintenance.
3. The bypass pipe is set to discharge a large amount of condensate at start-up, reducing the drain load on the trap.
4. When the trap is used to remove the condensate from the hot equipment, it should be installed on the lower part of the hot equipment so that the condensate pipe can be vertically returned to the drain to prevent the hot equipment from storing water.
5. The installation location should be as close as possible to the drainage point. If the distance is too long, air or steam will accumulate in the elongated pipe in front of the trap.
6. Hydrophobic problems should be considered when the level of steam mains pipelines is too long.
Sixth, safety valve
1. Before installation, the product must be carefully inspected to verify whether there is a certificate of competency and product specifications to determine the factory pressure conditions.
2. Safety valve should be arranged in the vicinity of the platform for inspection and maintenance.
3. Safety valve should be mounted vertically, the medium should flow from the bottom up, and to check the valve stem perpendicularity.
4. Under normal circumstances, the safety valve can not be set before and after the cut-off valve to ensure safe and reliable.
5 relief valve relief: When the medium is liquid, are generally discharged into the pipeline or airtight system; when the medium is gas, generally discharged to the outdoor atmosphere.
6. Oil and gas medium can be generally discharged into the atmosphere, safety vent vent pipe should be higher than the highest structure around the 3m, but the following should be closed confined system, to ensure safety.
7. The diameter of the population pipe should be as small as the inlet diameter of the valve. The diameter of the discharge pipe should not be less than the diameter of the outlet of the valve. The discharge pipe should be led outdoors and be installed with elbows so that the pipe outlet faces the safety zone.
8. Safety valve installation, when the safety valve and equipment and pipe connections for the opening welding, the opening diameter should be the same as the nominal diameter of the safety valve.
【Print】 【Close】
