When installing valves, keep these points in mind when using fluorine lined valves

When installing valves, keep these points in mind when using fluorine lined valves

Many valves have directional, such as globe valve, throttle valve, pressure reducing valve, check valve, etc., if installed in reverse, it will affect the use of the effect and life (such as throttle valve), or do not work at all (such as pressure reducing valve), and even cause danger (such as check valve). General valve, there is a direction mark on the valve body; If not, it should be correctly identified according to the principle of valve operation. The valve chamber around the globe valve is asymmetrical, fluid to let it from the bottom to the top through the valve port, so the fluid resistance is small (determined by the shape), open labor-saving (due to the medium pressure up), closed after the medium pressure packing, easy to repair, this is why the globe valve can not install the truth. Other valves have their own characteristics.
Valve INSTALLATION POSITION, must be easy to operate: EVEN if the installation is temporarily difficult, but also for the operator’s long-term work. Valve handwheel and chest alignment (generally 1.2 meters from the operating floor), so that the opening and closing of the valve is less effort. Floor valve handwheel should be facing up and not tilted to avoid awkward operation. The valve of the wall machine depends on the equipment, and the operator should also be left standing room. To avoid the operation of the sky, especially acid and alkali, toxic media, otherwise it is not safe. The gate should not be inverted (that is, the handwheel is down), otherwise the medium will be retained in the cover space for a long time, easy to corrode the stem, and for some process requirements taboo. It is extremely inconvenient to replace packing at the same time. Open STEM GATE VALVES, DO NOT INSTALL underground, otherwise due to damp corrosion of the exposed stem. Lift check valve, installation to ensure that the valve disc vertical, so that the lift flexible. Swing check valve, when installed to ensure that the pin level, in order to swing flexible. The pressure reducing valve shall be installed upright on the horizontal pipe, and shall not tilt in any direction.
Installation and construction must be careful, do not hit the valve made of brittle materials.
Before INSTALLATION, THE VALVE SHOULD be INSPECTED TO check specifications AND models to identify any damage, especially for the stem. Also turn a few times to see if it is skewed, because in the process of transportation, it is easy to hit the skewed stem. Also *** debris in the valve.
When LIFTING THE VALVE, THE ROPE SHOULD NOT BE TIED TO THE HANDWHEEL OR STEM TO AVOID DAMAGE TO THESE PARTS. It SHOULD BE TIED TO THE flange.
The line to which the valve is connected must be cleaned. Compressed air can be used to blow iron oxide filings, sand, welding slag and other sundries. These debris, not only easy to scratch the sealing surface of the valve, the large particles of debris (such as welding slag), but also can block the small valve, so that its failure. When INSTALLING THE SCREW VALVE, THE SEALING PACKING (WIRE AND aluminum oil OR PTFE RAW material belt) should be wrapped on the pipe thread, do not get into the valve, so as to avoid the valve memory volume, affect the medium flow.
When installing flange valves, pay attention to tighten the bolts symmetrically and evenly. The valve flange and the pipe flange must be parallel, the clearance is reasonable, lest the valve produces excessive pressure, even crack. For brittle materials and not high strength of the valve, special attention should be paid. The valve to be welded with the pipe shall be spot welded first, then the closed part shall be fully opened, and then welded dead.
Some valves must also have external protection, which is heat preservation and cold retention. The insulation layer is sometimes mixed with hot steam lines. What kind of valve should be heat or cold, according to the production requirements.
In principle, where the valve medium to reduce the temperature is too much, will affect the production efficiency or frozen valve, you need to keep warm, even mix heat; Where the valve is bare, adverse to production or cause frost and other adverse phenomena, you need to keep cold. Insulation materials are asbestos, slag wool, glass wool, perlite, diatomite, vermiculite, etc.; The cooling materials are cork, perlite, foam, plastic and so on.
Some valves, in addition to the necessary protection facilities, also have bypass and instrumentation. A bypass is installed. Easy to repair the trap. Other valves, also installed bypass. Bypass installation depends on valve condition, importance, and production requirements.
Stock valve, some packing has not been good, and some do not conform to the use of media, which needs to replace the packing.
Valve factory can not consider the use of thousands of different types of media, packing box is always filled with ordinary root, but when used, must let the packing in the medium to adapt.
When replacing packing, press in round by round. Each ring seam to 45 degrees is appropriate, ring and ring open 180 degrees. The packing height should consider the leeway for the gland to continue pressing, and now it is necessary to let the lower part of the gland press the packing chamber to an appropriate depth, which can generally be 10-20% of the total depth of the packing chamber. For demanding valves, the joint Angle is 30 degrees. The seam between the ring and the ring is staggered 120 degrees. In addition to the packing, but also according to the specific situation, the use of rubber O-ring (natural rubber resistant to 60 degrees Celsius weak alkali, butadiene rubber resistant to 80 degrees Celsius oil crystal, Fluorine rubber resistant to a variety of corrosive media below 150 degrees Celsius) three stacked polytetrafluoron ring (resistant to strong corrosive media below 200 degrees Celsius) nylon bowl ring (resistant to 120 degrees Celsius ammonia, alkali) and other forming filler. A layer of TEflon raw material tape can improve the sealing effect and reduce the electrochemical corrosion of the valve stem.
When pressing the seasoning, turn the stem at the same time to keep all around evenly, and prevent too dead, tighten the gland to force evenly, can not tilt.
Fluorine-butterfly valves use matters needing attention Fluorine-butterfly valves flange cover plate can’t open unless prepared and pipeline connection, otherwise PTFE flange surface may be caused by temperature difference, foreign bodies, knock against scratches or distortion and seal, such as moving cover board for inspection need, also must stay speed will cover plate to reset after inspection, in order to protect the PTFE flange surface.
Fluorine lining valve installation, fluorine lining valve use
1 fluorine lined valve flange cover plate can not be opened at will, unless it is ready to connect with the pipeline, otherwise PTFE flange surface may be due to temperature difference, foreign body caused by scratch or distortion and affect the sealing, such as the need to move the cover plate, also must be inspected after the speed to reset the cover plate, to protect PTFE flange surface.
2 fluorine lined valve and pipeline connection, generally and no longer use alone gasket, but with dissimilar material (metal surface, etc.) flange surface, should use appropriate gasket, in order to protect PTFE flange surface.
In THE USE OF THE SYSTEM, IF LEAKAGE OCCURS AT HIGH temperature, THE system temperature should be reduced to room temperature first, then find out the reason for maintenance.
During installation, flange nuts should be uniformly tightened in the diagonal direction (symmetric) and equipped with appropriate torque: a If the flange sealing surface leaks and the nut at the leakage position is locked, the nut at the leakage position should be loosened for half a turn and the opposite side of the nut should be tightened again with the same torque; B If the above method is still not stop leakage, should check PTFE flange surface whether there are concave and convex indentation, scratch, then available yarn paper, cloth to be leveled and reconnected.
Do NOT DO ANY HIGH TEMPERATURE WELDING WORK ON FLUORINE LINED VALVES TO avoid LONG-TERM DAMAGE TO THE LINING LAYER.
6 Fluorine lined valves should be stored in a dry and ventilated room. Do not stack them.
The FLUORINE LINED VALVE AFTER MAINTENANCE SHALL BE tested and qualified according to relevant standards before being installed.
When MANUALLY OPERATING THE FLUORINE LINED VALVE, IT IS NOT ALLOWED TO FORCE OPEN AND CLOSE THE VALVE WITH the HELP OF OTHER levers.
9 directional requirements of fluorine lined valve in the installation of the medium should pay attention to the direction of the arrow on the valve body, and ensure that the operation and maintenance is convenient.
10 long-term storage of the fluorine lined valve sealing pair should be slightly open and separated, to avoid long-term deformation of the sealing surface under long-term pressure, affecting the sealing performance and service life.