Gate construction scheme and matters needing attention

Gate installation will be encountered in many construction occasions. Gate refers to a device that can control the opening and closing of materials. Its materials are varied, and different materials are used in different occasions. Its installation also determines whether the next construction can be carried out smoothly. Many people often know little about the installation methods and precautions of the gate. Therefore, this article will give you an overview of these installation methods and precautions for your reference when necessary.

Construction method

Care must be taken during installation and construction not to hit the valve made of brittle materials.

Before installation?

1. Carefully check whether the models and specifications of all valves meet the design requirements.

(According to the valve model and factory instructions, check whether they can be used under the required conditions, and carry out water pressure or air pressure test if necessary. )

2, in addition, should also check whether the packing is in good condition, gland bolts have enough adjustment allowance, and check whether the valve stem and valve disc are smart, and whether there is a stuck and skewed phenomenon.

(The sealing surface of the valve disc must be tightly closed, and the thread quality of the threaded valve should be checked. Unqualified valves cannot be installed and should be stacked or marked separately. )

3. Remove the sundries in the valve.

Installation process

1. When lifting the valve, the rope should not be tied to the handwheel or valve stem to avoid damaging these parts, but should be tied to the flange.

2. The pipeline connected to the valve must be cleaned.

Compressed air can be used to blow away iron oxide chips, mud sand, welding slag and other sundries. These sundries are not only easy to scratch the sealing surface of the valve, but also block the small valve and make it invalid.

When installing the spiral valve, the sealing filler (aluminum oil or ptef) should be wrapped on the thread of the pipeline to prevent it from entering the valve and accumulating in the valve to affect the medium circulation.

When installing flanged valves, pay attention to tighten the bolts symmetrically and evenly. Valve flange and pipeline flange must be parallel and have a reasonable gap to avoid excessive pressure or even cracking of the valve. Special attention should be paid to brittle materials and low-strength valves. Valves that must be welded to the pipeline should be spot-welded first, then the closing parts should be fully opened and then welded to death.

3. Protective measures

Some valves also need external protection, that is, heat preservation and cold preservation. Sometimes hot steam pipes are mixed in the insulation layer. Which valve should be kept warm or cold depends on the production requirements.

In principle, if the temperature of the medium in the valve decreases too much, which will affect the production efficiency or freeze the valve, it is necessary to keep warm or even mix heat; If the valve is exposed, which is not conducive to production or leads to frosting and other undesirable phenomena, it is necessary to keep the temperature low. Thermal insulation materials include asbestos, slag wool, glass wool, perlite, diatomite, vermiculite, etc. Cold insulation materials include cork, perlite, foam, plastic and so on.

4. Bypass and instrument

In addition to the necessary protective facilities, some valves are also equipped with bypass and instruments. Bypass has been installed. It is convenient for the maintenance of the trap. Other valves are also equipped with bypass valves. Whether to install bypass depends on the condition, importance and production requirements of the valve.

5, packing replacement

For the valves in stock, some fillers are not easy to use, and some are inconsistent with the medium used, so it is necessary to replace the fillers.

Valve manufacturers can't consider using all kinds of media, and stuffing boxes are always filled with ordinary fillers, but when they are used, the fillers must be suitable for the media.

When replacing the packing, press it in round and round. The joint of each circle should be 45 degrees, and the circles should be connected at 180 degrees. The packing height should consider the space where the gland continues to be compressed. Now, the packing chamber under the gland should be pressed to an appropriate depth, which is usually 10-20% of the total depth of the packing chamber. ? For demanding valves, the joint angle is 30 degrees. The joints between rings are staggered 120 degrees.

In addition to the above fillers, rubber O-rings (natural rubber can resist weak alkali below 60 degrees Celsius, nitrile rubber can resist oil crystallization below 80 degrees Celsius, and fluororubber can resist various corrosive media below 65,438+050 degrees Celsius), nylon bowl-shaped rings (ammonia and alkali below 65,438+020 degrees Celsius) and other molding fillers can be used according to specific conditions. Wrapping a layer of ptef around the common asbestos packing can improve the sealing effect and reduce the electrochemical corrosion of the valve stem. When pressing seasoning, rotate the valve stem at the same time to make the periphery uniform and prevent it from being pressed too hard. Tighten the gland evenly and don't tilt.

Matters needing attention

Direction and position

Many valves are directional.

Such as stop valves, throttle valves, pressure reducing valves, check valves, etc. If installed backwards, it will affect the service effect and service life (such as throttle valve), or it will not work at all (such as pressure reducing valve), or even cause danger (such as check valve). Generally, valves have directional signs on the valve body. If not, it should be correctly identified according to the working principle of the valve.

The valve cavity of the stop valve is asymmetrical left and right, and the fluid should pass through the valve port from bottom to top, so that the fluid resistance is small (determined by the shape), and it is labor-saving to open (due to the upward pressure of the medium). After closing, the medium does not press the filler, which is convenient for maintenance. This is why the stop valve cannot be reversed. Other valves also have their own characteristics.

Valve installation position must be easy to operate.

Even if the installation is temporarily difficult, it is necessary to consider the long-term work of the operators. It is best to aim the handwheel of the valve at the chest (generally, the distance from the operating table1.2m), so that it is more labor-saving to open and close the valve. The handwheel of floor-standing valve should be upward, not inclined, so as to avoid embarrassing operation. The machine valve against the wall should also leave room for the operator to stand. Avoid aerial work, especially in acid, alkali and toxic media, otherwise it will be unsafe.

Don't turn the gate upside down (i.e. the handwheel is downward), otherwise the medium will stay in the bonnet space for a long time, which is easy to corrode the valve stem, which is taboo for some process requirements. At the same time, it is very inconvenient to replace the filler. Open-stem gate valves should not be installed underground, otherwise the exposed valve stem will be corroded due to moisture. When installing the lifting check valve, make sure that its disc is vertical, so as to lift it flexibly. When installing swing check valve, make sure its pin shaft is horizontal so as to swing flexibly. The pressure reducing valve shall be installed vertically on the horizontal pipeline and shall not be inclined in all directions.

Through the above introduction, we have a general understanding of the gate installation methods and matters needing attention. It can be seen that in order to install sluice wells, it is very important to choose the installation location first, and then select materials according to different functional requirements. Everyone should pay attention to empty the debris in the gate before installation, so as to avoid blocking and interfering with the subsequent construction. It is worth noting that the installation should pay attention to directionality, which has a great impact on the later use, and many people often ignore this.

Tubatu Online provides you with "each decoration quotation, 1-4 local decoration companies, 3 sets of decoration design schemes" and the decoration pit avoidance strategy for free! Click this link:/Zhu Ye /zxbj-cszy.php? to8 to _ from = SEO _ zhidao _ m _ jiare & amp； Wb, you can get it for free ~