It’s important to keep these points in mind about valve installation! Notes for the installation of German original imported valves

It’s important to keep these points in mind about valve installation! Notes for the installation of German original imported valves

The quality of valve installation directly affects the use, so careful attention must be paid to it.
(a) valve installation direction and position
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.
(2) valve installation and construction
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.
(3) valve protection measures
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.
(4) Bypass and instrumentation
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.
(5) Replacement of packing
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.
Notes for the installation of German original imported valves
Before valve installation, ensure that the valve meets the design requirements and relevant standards.
When handling and installing valves, beware of bumps and scratches
Before INSTALLING THE VALVE, THE INSIDE OF THE PIPELINE SHOULD be cleaned to REMOVE impurities such as iron filings to prevent the valve seal seat from containing foreign bodies. In addition, the valve should be installed in the closed state.
Lifting valve operation. The VALVE SHALL BE CORRECTLY LIFTED AT THE SPECIFIED LIFTING POSITION, AND SHALL NOT BE LIFTED OR PULLED UNDER local force.
When installing the valve, it is necessary to determine whether the flow direction of the medium, the installation form and the position of the handwheel conform to the regulations.
Installation of flanged connection valves
(1) The flange surface of valve and piping should be free from damage, scratches, etc., and kept clean. Especially the use of metal gaskets (oval or octagonal section), flange grooves and gaskets should be consistent,
It should be coated with red lead to make sure its sealing condition is good.
(2) The perpendicularity of the flange surface on the pipe and the center line of the pipe and the error of the flange bolt hole should be within the range of the allowed value. Valve and piping center line should be consistent before installation.
(3) When connecting two flanges, first of all, the flange sealing face and gasket should be pressed evenly, so as to ensure that the flange is connected by the same bolt stress.
(4) When tightening bolts, use a wrench that matches the nut. When using oil pressure and pneumatic tools for tightening, pay attention not to exceed the specified torque.
(5) The fastening of the flange should avoid uneven force, and should be tightened in order in the direction of symmetry and compatibility.
(6) After installation of flange, make sure that all bolts and nuts are firm and uniform.
(7) The material of bolts and nuts must meet the regulations. After fastening, the bolt head should be exposed from the nut two pitch is appropriate.
(8) Bolt and screw fastening, in order to prevent vibration caused by loosening, to use gaskets. In order to avoid adhesion between threads at high temperature, the thread parts should be coated with anti-adhesion agent (molybdenum disulfide) during installation.
(9) For high temperature valves above 300 degrees Celsius, after the temperature rises, the flange connection bolts, valve cover fastening bolts, pressure seal bolts and packing pressure cover bolts must be tightened again.
(10) The low temperature valve is installed in the state of atmospheric temperature. In practical application, when the medium passes through, it becomes a low temperature state. Due to the formation of temperature difference, flanges, gaskets, bolts and nuts, etc., shrink, and because the materials of these parts are not the same, their linear expansion coefficient is also different, forming a very easy to leak environmental conditions. From various objective conditions, when tightening bolts at atmospheric temperature, it is necessary to adopt the torque that takes into account the contraction factors of each part part at low temperature