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Commonly used in industrial valve summary
Source:未知   Author:admin   Time:2012-08-01 14:27   Click:
Commonly used in industrial valve summary       Valve in all temperature range adapted to most of the switching operations, the vibration of hydrocarbons, as well as utilities. Vibration operation, the gate valve may be from their normal position to open or close. Unless the stem packing is carefully adjust the gate valve torque characteristics better than ball valves and plug valves, but there is no convenient operational features of the 90-degree spins.        For manual operation the size of DN50 (2in) in size or larger valve should be equipped with flexible gate or expander gate. Wedge gate valve is usually the valve cavity overpressure protection.        Unprotected rod valve is not recommended. Because the marine environment will corrode the exposed stem and thread to make the valve difficult to operate and easy to damage the stem packing.        The role of the board with a reverse valve, adapted to the automatic shutdown system operation. For these valves using a simple push-pull operation, therefore, to avoid the usually ball valves and plug valves required by complex joystick cam. With power operated movable part on the gate valve can be closed, eliminating the pollution caused due to the paint and corrosion products.        The gate valve can not be used for throttling operation. In particular, the fluid containing sand, throttling will damage the sealing surface.        The soft sealing gate valve operating temperature limit of the sealing material.        Cut-off valve        Need good throttle control (such as control valves, bypass piping or a small vent) valve, globe valve is the most appropriate.        Ball Valves        When the operating temperature between -29 ° C to 200 ° C, most of the manual (open and closed) ball valve adapted to hydrocarbons and utility system operation, the ball valve above 100 ℃, the application should be carefully considered soft seal the temperature limit of the material should be above 100 ℃. In the heat or abrasion is more serious job, you should consider the application of metal sealed ball valve, but should indicate the torque must increase.        The ball valve has two designs, the float type and trunnion ball valves. The design of the float type valve, high pressure or large diameter will produce higher operating torque, but a good sealing.        Ball does not apply to the throttle, because, when the valve is partially open, the sealing surface will be damaged by exposure in the processing fluid.        For critical operations, should consider buying a ball valve with a tee and valve stem lubrication accessories, because the lubrication can prevent minor leakage, reduce operating torque, if you need a valve with shutdown and discharge of two functions, you should sphere independent of the lubrication accessories vent hole.        Check valve        The check valve in a variety of forms: including swing, lift, ball, piston and separation circle circled the check valve. Among them, the full-type swing check valve adapted to most non-fluctuations. Swing check valves are also used in the vertical pipe (flow direction is upward). The valve, a stop block to prevent dead spots on the valve flap is more than open.        Swing check valves can not be used for the downward flow direction on the vertical pipe for low volatility, low flow rates, local, Swing check valve will vibrate and will eventually damage the sealing surface. In order to extend the life of the valve can be coated with a layer of Stellite. In order to reduce the leakage of the valve seat, you should use the flexible seal. The removable seat should be preferred, because they are easy to maintain, and easy to replace the valve seals.        Swing check valves should be selected to the bonnet of a screw or bolt connection, in order to check and repair the valve disc and seat. In many cases, repairable high-voltage swing check valve in the pipe, the minimum size is DN65 (2.5NPS) or DN80 (3NPS).        The slim design of the rotary valve (save space), adapted to be installed between two flanges. Normal this type of check valve failure to open and repair needs to be removed from the pipeline.        Double-disc slim check valve for small-footprint, light weight, it is often used in offshore oil. Due to fatigue will lead to spring failure, the double-disc slim check valve can not be used for pulse operation. But you can consider with no impact to (or automatically) check valve or rotary check valve.        Lift check valve can only be used in small-caliber (the DN40), high-pressure pipeline deal with cleaning fluid. Lift check valve can be designed for horizontal pipe or vertical pipes, but they are not interchangeable. Lift check valves are usually operated by gravity, they may be a paraffin wax or debris impacts arising from the blockage.        The ball check valves and lift check valves are very similar. As the ball is lifting by the fluid pressure, so this type of check valve and rotary check valve that the valve off a tendency to impact. Therefore, greater than of DN50 (2in) pipes for the frequent change of the flow of clean fluid is relatively good.        Balance, axial piston, automatic check valve is recommended to use the pipeline of the flow fluctuations, such as reciprocating compressors and pumps of the export pipeline. They are not suitable for use in fluid sand or impurities in the pipeline. The piston check valve is equipped with an orifice to control the activities of the piston. The orifice for the liquid than for gas orifice large. Piston check valve designed for the gas pipeline can not be used for liquid operations, unless the replacement of the orifice in the piston.        Butterfly valve        Ordinary butterfly valve rough throttle and low-voltage, non-hydrocarbon, non-dangerous job, they are not suitable for use as containers, cans and other important shut-off valve. Temperature is above 65 ° C or pressure level is higher than ASME150 or hazardous fluid working conditions should be applied to wireless butterfly valves. Just a small moment can make the butterfly valve vibration turned on, so the handle should be equipped with locking devices.        Diaphragm valve (piece-shaped)        In the design of this valve using synthetic rubber diaphragm and the valve stem connection, close the valve is achieved by the diaphragm pressure in the metal convex stage (which is part of the body). Diaphragm Valves are mainly used in the operations of the low pressure water 1400kPag (200 psig or less), they are particularly suitable for systems that contain sand and other solid particles.        Stopcock        Stopcock to adapt in the hydrocarbon and utility system operation. Lubrication and non-lubricated plug valves with 90 degree rotation in two designs. Lubricated plug valves must be lubricated on a regular basis, so that good sealing, and easy to operate, the number of refueling depends on the conditions of use. Its lubricating function to prevent the valve jamming is a solution.        In the design of non-lubricated, sealed Teflon, nylon and other soft materials. They do not require regular maintenance lubrication, but when the valve is set in a long time in one place, and then rotating it more difficult. Based on these characteristics, depending on the use of the environment (conditions) to select the valve.        Needle valve        The needle valve is basically a small cut-off valve. They are often used as a shut-off valve of the meter and pressure gauge for instrument air, gas and hydraulic fluid flow throttling is also used to reduce pressure fluctuations in the meter pipe. The needle valve channel is very small, very easy to plug, used to consider this point.撤消修改字典{window.jstiming.load.tick('rsw');window.jstiming.load.tick('rsl');window.jstiming.load.tick('rtl');function _njClk(e){document.body.className+=' nj';var i=new Image();i.src='/gen204?njclk=1';i.onload=function(){i.onload=null;};}var slgms=document.getElementById('gt-sl-gms');var tlgms= document.getElementById('gt-tl-gms');slgms.onclick=tlgms.onclock=_njClk;}
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