Valve installation quality, direct impact on use, it must be careful attention.

1.Direction and position

Many valve is directional, such as cut-off valve, throttle valve, pressure reducing valve, check valve, if installed anti-flip, it will affect the results and longevity (eg throttle), or does not work (eg valve), and even dangerous (such as check valves). General valve, the valve on the direction flag; in case it does not, according to the valve works, correctly identified.

Valve asymmetrical valve chamber , the fluid to make it from the bottom up through the valve port , so that the fluid resistance is small ( as determined by the shape ) , open the effort ( because of media pressure up ) , after the closure of the media do not pressure filler , easy maintenance . That is why the non- safety valve against the truth. Other valves have their own characteristics .

Valve mounting location must be accessible to the operation ; even install some temporary difficulties , but also for the sake of the operator's long-term work . Best valve hand wheel and chest aligners ( generally 1.2 m from the floor operation ) , so that opening and closing the valve more provincial fresh. Landing valve hand wheel should be facing up , do not tilt to avoid awkward operation . Wall unit by the device of the valve, but also leaving a room for an operator to stand . To avoid sky operation , especially acid, toxic media , otherwise very safe. Do not flip gate ( ie, hand wheel down ) , otherwise it would be retained in the valve cover long-term media space , stem susceptible to corrosion , but also for some of the technical requirements of the taboo. At the same time replace the packing is very inconvenient .

Rising stem gate valve , do not install in the ground , or due to moisture and corrosion exposed stem .

Lift check valves , installation to ensure its vertical valve for lifting flexible.

Swing check valves , installation to ensure that its pin levels in order to swing flexible.

To erect valve installed in horizontal pipelines , do not tilt in all directions .

2.Construction work

Installation and construction must be careful and avoid the impact of brittle materials produced by the valves.

Before installation , you should make a check valve , check the specifications, the identification of damage, especially for the stem . Also a few turns to see if skewed , because the transport process, most likely hit the crooked stem . Also clear debris inside the valve .

Valve lifting, rope Do not tie the hand wheel or stem to avoid damage to these parts , it should be based on the flange .

The valve is connected to piping , must be cleaned. Used compressed air to remove iron oxide dust, silt , welding slag and other debris. These debris, not only easy to scratch the sealing surface of the valve , where large particles debris ( such as welding slag ) , but also blocked the small valve to fail .

Install screw valve , should seal packing ( hemp leaded oil or Teflon tape ) , wrapped in pipe threads , do not get the valve , the valve in order to avoid memory plot , affecting medium flow .

Mounting flange valve , pay attention to symmetry evenly Bolt . Valve flange and pipe flanges must be parallel , the gap is reasonable, in order to avoid excessive pressure on the valve , and even cracking. For brittle material and strength of the valve is not high , with particular attention . Valves and pipe welding required , you should spot , and then shut down parts open, and then welded shut .

3.Protection facilities

Some valves need to have external protection, which is heat and cold. Sometimes also add insulation layer with hot steam pipes. What kind of valve should be warm or cold, according to the production requirements. Principle to say, where the lower the temperature inside the valve too much media will affect productivity or frozen valves, you need insulation, even heating; Where valves nudity, or cause frost on the production adversely and other undesirable phenomena, you need cold. Insulation materials are asbestos, slag wool, glass wool, perlite, diatomaceous earth, Vermiculite, etc.; cold material is cork, perlite, foam, plastic.

Long-term need of water, steam valves must let go of water.

4.Bypass and instrumentation

Some valves, in addition to the necessary protection facilities, but also a bypass and instrumentation. Installed a bypass for easy trap maintenance. Other valves, but also the bypass is installed. Bypass is installed, depending on the valve position on the importance and production requirements.

5.Packing replacement

Stock valves, some filler has been so bad, some discrepancies with the use of the media, which need to replace the packing.

Valve manufacturer can not consider the use of units of one thousand million class of different media, always filled with ordinary stuffing box packing, but when used, must be allowed to adapt to the filler and the media.

When replacing packing, to circle around pushed. Each lap joints at 45 degrees is appropriate, ring and ring joints staggered 180 degrees. Continue to consider the gland packing height pressed room, now we allow the gland packing the lower pressure chamber proper depth, this depth is generally room for filler 10-20% of the total depth.

Valves that require high seams angle of 30 degrees. Stagger joints between windings 120 degrees.

In addition to the packing of the Department, but also depending on the circumstances, the use of rubber O-ring (natural rubber resistant to 60 degrees Celsius below the weak base, nitrile rubber oil resistant 80 degrees Celsius, fluorine rubber resistant to 150 degrees Celsius in a variety of corrosive media) three stacked PTFE rings (resistant to 200 degrees Celsius below the strong corrosive media) nylon bowl rings (resistant to 120 degrees Celsius, ammonia, alkali) and other forming filler. Outside the ordinary asbestos packing, pack a layer of Teflon tape, can improve the sealing effect, reducing stem electrochemical corrosion.

In the compression packing, we needed to turn the valve stem to keep four weeks evenly and prevent too dead, tighten the gland to force uniform, can not tilt.

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