Pipe valves are everywhere. If there are any problems, just these 4 aspects are needed to solve the pipe valves. What should we pay attention to when installing them?

Pipe valves are everywhere. If there are any problems, just these 4 aspects are needed to solve the pipe valves. What should we pay attention to when installing them?
What are the functions of pipeline valves?

How to install it?
What do common signs mean?
If there is a fault, how to repair it? The 4 functions of the pipeline valve
First, cut off and release medium
This is the basic function of the valve, usually choose a straight passage valve, its flow resistance is small.
Downward closed valve (globe valve, plunger valve) because of its tortuous flow path, flow resistance is higher than other valves, so less selected. Closed valves may be used where high flow resistance is permitted.
Two, control the flow
A valve that is easy to adjust is usually chosen to control flow. Downward CLOSING valves (such AS GLOBE valves) ARE SUITABLE FOR THIS PURPOSE BECAUSE THE SEAT size IS PROPORTIONAL TO THE STROKE OF THE SHUTOFF.
Rotary VALVES (PLUG, butterfly, BALL valves) and FLEXURE BODY VALVES (PINCH, DIAPHRAGM) ARE ALSO AVAILABLE FOR THROTTLING CONTROL, but USUALLY ONLY IN a limited range of valve DIAMETERS.
Gate VALVE IS A disc shaped gate to the circular seat port to do transverse motion, it only in close to the closed position, can better control the flow, so usually not used for flow control.
Three, commutation shunt
The valve may have three or more channels, depending on the need for reversing and diverting. Plug and ball valves are more suitable for this purpose, and therefore, most valves used for reversing and diverting are selected as one of these valves.
However, IN SOME CASES, other TYPES OF VALVES MAY ALSO BE USED AS commutATION diverTERS, PROVIDED THAT TWO or MORE VALVES ARE properly connected to EACH other.
4. Medium with suspended particles
When the medium with suspended particles, ** suitable for the use of the closing parts along the sealing surface of the sliding valve with wiping action.
If THE SHUTOFF IS VERTICAL TO THE BACK AND FORTH MOVEMENT OF THE SEAT, PARTICLES MAY BE TRAPPED, SO THIS VALVE IS ONLY SUITABLE FOR BASICALLY CLEAN MEDIA UNLESS THE SEALING MATERIAL ALLOWS FOR PARTICLES TO BE EMBEDDED. Ball valves and plug valves wipe the sealing surface during opening and closing, so they are suitable for use in media with suspended particles. 3 installation problems of pipe valves
I. Check before installation
1. Carefully check whether the valve model and specification meet the requirements of the drawing.
2. Check whether the stem and disc open flexibly and are not stuck or skewed.
3. Check whether the valve is damaged, and whether the thread of the threaded valve is straight and intact.
4. Check whether the combination of the seat and the valve body is firm, the valve disc and the valve seat, the valve cover and the valve body, the connection between the valve stem and the valve disc.
5. Check whether the valve padding, packing and fasteners (bolts) are suitable for the requirements of the nature of the working medium.
6. The old or used for a long time pressure reducing valve should be disassembled, dust, sand and other debris must be cleaned with water.
7.*** opening seal, check the sealing degree, the valve disc must be tightly closed.
2. General provisions for installation
1. The installation position of the valve should not interfere with the operation, disassembly and maintenance of the equipment, pipeline and valve body itself, while taking into account the appearance of the assembly.
2. For valves on horizontal pipelines, install the valve stem upward or at a certain Angle, do not install the handwheel downward. The valve, stem and handwheel on the high altitude pipe can be installed horizontally, and the opening and closing of the valve can be remotely operated by the chain in the vertical low place.
3. Symmetrical arrangement, neat and beautiful; The valve on the riser, under the premise of allowing the process, the valve handwheel to chest height ** suitable operation, generally 1.0-1.2m from the ground is appropriate, and the valve stem must be installed along the direction of the operator.
4. The center line elevation of the valves on the side-by-side riser is relatively consistent, and the net distance between the handwheels is not less than 100mm; Valves on side-by-side horizontal lines should be staggered to reduce pipe spacing.
5. When installing heavy valves on water pumps, heat exchangers and other equipment, valve supports should be set; When the valve is operated frequently and installed above 1.8m from the operating surface, a fixed operating platform should be provided.
6. If there is an arrow mark on the valve body, the arrow point is the flow direction of the medium. When installing the valve, be careful that the arrow points in the same direction as the medium in the pipeline.
7. When installing flange valves, ensure that the two flange end faces are parallel and concentric, and do not use double gaskets.
8. When installing threaded valves, a threaded valve shall be equipped with a live connection for easy disassembly. The setting of the live connection should consider the convenience of maintenance, usually the water flow through the valve and then through the live connection.
Three, installation precautions
1. The valve body material is mostly made of cast iron, brittle, so it can not be impacted by heavy objects.
2. When handling the valve, do not allow to throw; When LIFTING AND HOISTING THE VALVE, THE rope SHOULD be tied to the valve body, and it is forbidden to tie to the handwheel, valve stem and flange bolt hole.
3. The valve should be installed in the most convenient place for operation, maintenance and overhaul. It is forbidden to bury it underground. The valve on the pipe in the direct buried and trench should be equipped with the inspection well room, so as to facilitate the opening, closing and adjustment of the valve.
4. Ensure that the thread is intact and undamaged, and wrap the thread with hemp, lead oil or PTFE raw material belt. When turning the buckle, it is necessary to use a wrench to jam and screw the hexagonal valve body at one end of the pipe.
5. When installing flanged valve, pay attention to tighten the connecting bolt along the diagonal direction, and exert even force when twisting to prevent the gasket from running off or causing deformation and damage to the valve body.
6. The valve should be kept closed during installation. For THREADED valves close to the wall, it is often necessary to remove the stem, disc and handwheel to turn. During disassembly, the valve should be removed after twisting the handwheel to keep the valve open. 6 common installation methods of pipe valves
A, gate valve,
Also known as gate valve, is the use of gate to control the opening and closing of the valve, by changing the cross section to adjust the pipeline flow and opening and closing of the pipeline. Gate valve is used for the fluid medium to do full opening or full closing operation of the pipeline.
Gate valve installation generally without directional requirements, but can not be inverted.
Two. Stop valve
The valve that uses the disc to control the opening and closing. By changing the clearance between disc and seat, that is, changing the size of the channel section to adjust the medium flow or cut off the medium path. Pay attention to the flow direction of the fluid when installing the globe valve.
Installation globe valve must comply with the principle is, the fluid in the pipeline from the bottom through the valve hole, commonly known as “low into high”, do not install reverse.
Three, check valve
Check valve, also known as check valve, check valve, is a valve in the valve before and after the pressure difference under the action of automatic opening and closing, its role is to make the medium only do one direction of flow, and prevent the medium reverse flow back.
Check valve according to its different structure, there are lift type, swing type and butterfly type. Lift type check valve and horizontal and vertical points.
When installing the check valve, attention should also be paid to the flow direction of the medium.
Four, pressure reducing valve
1. The vertically installed pressure reducing valve group is generally arranged along the wall at a suitable height from the ground; The pressure reducing valve set installed horizontally is generally installed on the permanent operation platform.
2. The application of steel in the two control valves (often used in the globe valve) on the outside of the wall, constitute a bracket, bypass pipe is also stuck in the bracket, leveling and alignment.
3. The pressure reducing valve should be installed upright on the horizontal pipeline, not inclined, the arrow on the valve body should point to the direction of the medium flow, not reverse.
4. Stop valves and high and low pressure pressure gauges should be installed on both sides to observe the pressure changes before and after the valve. The diameter of the pipe after the pressure reducing valve should be 2#-3# larger than the diameter of the inlet pipe before the valve, and installed with a bypass pipe for maintenance.
5. The pressure equalizing pipe of the film pressure reducing valve should be connected to the low pressure pipe. A safety valve shall be set for the low pressure pipeline to ensure the safe operation of the system.
6. When used for steam decompression, the drain pipe should be set. For pipe systems with higher purification requirements, filters should be set before the pressure reducing valve.
7. After the installation of the pressure reducing valve group, the pressure reducing valve and safety valve should be tested, washed and adjusted according to the design requirements, and the adjusted mark should be made.
8. When flushing the pressure reducing valve, close the inlet valve of the decompressor and open the flushing valve for flushing.
Five, the trap
1. The cut-off valve (globe valve) should be set before and after, and the filter should be set between the trap and the front cut-off valve to prevent the dirt in the condensate from blocking the trap.
2. A check pipe should be set between the trap and the rear cut-off valve to check whether the trap works normally. If the check pipe is opened and a large number of steam is generated, it indicates that the trap is broken and needs maintenance.
3. The bypass pipe is set to discharge a large amount of condensed water during startup to reduce the drain load of the trap.
4. When the trap is used to remove condensate water from the hot equipment, it should be installed at the bottom of the hot equipment so that the condensate pipe can be connected to the trap vertically to prevent water storage by the hot equipment.
5. The installation position should be as close as possible to the drainage point. If the distance is too far, air or steam will accumulate in the slender pipe in front of the trap.
6. When the horizontal pipeline of the dry steam pipe is too long, the hydrophobic problem should be considered.
Six, safety valve
1. Before installation, the product must be carefully checked to see whether there is a certificate of quality and product instruction, so as to clarify the constant pressure situation when leaving the factory.
2. The safety valve should be placed as close to the platform as possible for inspection and maintenance.
3. The safety valve should be vertically installed, the medium should flow from the bottom to the top, and check the verticality of the valve stem.
4. In general, the safety valve can not be set before and after the cut-off valve to ensure safety and reliability.
5 safety valve pressure relief: when the medium is liquid, generally discharged into the pipeline or closed system; When the medium is gas, it is generally discharged to the outdoor atmosphere.
6. The oil and gas medium can generally be discharged into the atmosphere. The outlet of the relief valve empty pipe should be 3m higher than the surrounding tall structure, but the following cases should be discharged into the closed system to ensure safety.
7. Population pipe diameter, ** should be equal to the inlet pipe diameter of the valve; The DIAMETER OF THE DISCHARGE PIPE SHALL NOT BE LESS THAN THE OUTLET DIAMETER OF THE VALVE, AND THE DISCHARGE PIPE SHALL BE LED OUTSIDE AND INSTALLED WITH a BEND SO THAT THE OUTLET OF THE PIPE is ORIENTED TO a SAFE area.
8. When the safety valve is installed, when the connection between the safety valve and the equipment and the pipeline is open hole welding, the opening diameter should be the same as the nominal diameter of the safety valve.
What should we pay attention to when installing pipeline valves?
In the fluid piping system, the valve is the control element, its main role is to isolate the equipment and piping system, regulate the flow, prevent backflow, regulate and discharge pressure. It can be used to control the flow of air, water, steam, all kinds of corrosive media, mud, oil, liquid metal and radioactive media. Because the pipeline system to choose the right valve is very important, in the construction process, the quality of pipeline valve installation, directly affect the future normal operation, so must pay attention to.
Check items before installation
1. Carefully check whether the valve model and specification meet the requirements of the drawing.
2, check whether the stem and disc open flexibly, whether there is stuck and skew phenomenon.
3. Check whether the valve is damaged, and whether the thread of the valve is straight and intact.
4, check whether the combination of the valve seat and the valve body is firm, the valve disc and the valve seat, the valve cover and the valve body, the valve stem and the valve disc.
5. Check whether the valve padding, packing and fasteners (bolts) are suitable for the requirements of the nature of the working medium.
6, the old or used for a long time should be disassembled, dust, sand and other debris must be cleaned with water.
7, the opening seal, check the sealing degree, the valve disc must be closed tightly.