Natural gas pipeline installation is complicated,

2022-07-22
  • Detail

With the improvement of people's living standards, more and more people use natural gas in residential areas. Many people know natural gas, but they don't understand how natural gas pipelines are installed. Today, Xiaobian will give you the knowledge of popular science and see what steps are taken in the installation of natural gas pipelines

with the improvement of people's living standards, more and more people in the community use natural gas. Many people know natural gas, but they don't understand how natural gas pipelines are installed. Today, Xiaobian will give you the knowledge of popular science and see what steps are taken in the installation of natural gas pipelines

natural gas pipeline installation

I. process flow

Installation Preparation → Prefabrication processing → Main pipe installation → Riser installation → Branch pipe installation → Installation of valves and gas meters → Strength and tightness test → Pipe purging → Corrosion prevention, oil painting

1, operation method

1.1 installation preparation, carefully get familiar with the drawings, make preparations according to the construction method determined by the construction scheme and the specific measures of technical disclosure, refer to the relevant professional equipment drawings and decoration architectural drawings, check whether the coordinates and elevations of various pipelines intersect, timely study and solve problems with the designer and relevant personnel, make change negotiation records, and in the structural construction stage, Cooperate with civil engineering to reserve holes, casings and embedded parts

1.2 prefabrication and processing: according to the design drawing, draw the construction sketch of pipeline shunting, pipe diameter, reducing, reserved nozzle, valve position and so on, mark the actual installation structural position, measure the actual installation accurate size according to the marked sections, draw it on the construction sketch, and finally prefabricate and process according to the sketch. The one-time feed amount of pipe thread should not be too large. Set it again, adjust the dial to increase the feed amount, and then set it again. General requirements: dn< 25 can be assembled at one time. DN25— 40mm should be set twice. DN≥ 50mm shall be sleeved in three times. The screw thread shall be free of defects such as disordered threads, partial threads and burrs. The fracture and notch shall not exceed 10% of the whole thread. The tightness of the screw thread shall be appropriate

2. Main pipe installation

2.1 install the clamp frame according to the design requirements or the spacing specified in the specifications. When installing the elevator, first put the hanging rod on the section steel support according to the slope direction and sequence, put the lifting ring on the pipe according to the spacing position, and then lift the pipe, put on the bolt, screw the nut, and fix the pipe. Install the pipe on the bracket, first put the pipe in place on the bracket, install the first section of pipe with a U-shaped clamp, and then install the second section of pipe. Later, all sections of pipe should follow this, and tighten the bolts

2.2 indoor pipeline installation generally should first install the lead-in pipe, and then install the riser, horizontal pipe, branch pipe, etc. When the indoor horizontal pipeline encounters obstacles and the straight pipe cannot pass through, simmer bending or use pipe fittings to bypass the obstacles, such as duck neck bending, grab bending, 45 DEG; 90° Elbow. When the walls of two floors are not on the same plane, “ Turn back and forth ” Form laying

3. Riser installation

3.1 check whether the position of reserved holes on each floor is vertical, and check whether the hanging line, eye picking and clip planting. Transport the prefabricated pipes to the installation site in numbered order

3.2 remove the valve cover before installation. If there is a steel sleeve, put it on the pipe first, and install it from the first section according to the number. Apply lead oil to wrap the mahjong riser, align it with the interface, turn the buckle, one pipe wrench bites the pipe fitting, and one pipe wrench twists the pipe to a proper tightness, align it with the requirements of the alignment mark, and the screw thread is exposed for 2— 3 buckles, the reserved opening is flat, and the hemp head is cleaned

3.3 check whether the elevation, direction, etc. of each reserved opening of the riser are accurate and flat. Loosen the pipe clamp planted in advance, put the pipe into the card, tighten the bolts, use suspenders and plumbers to find the verticality from the first section, straighten the steel casing, and finally cooperate with the civil engineering to fill the holes, and the reserved openings must be equipped with temporary plugs. The installation direction of the riser cut-off door shall be convenient for operation and repair

3.4 gas risers are generally laid in kitchens or staircases. When the diameter of the indoor riser is not greater than 50mm, a flexible joint is generally installed every other floor, and the position is not less than 1.2m from the ground. When there is a valve, a union must be installed, and the position of the union should be set behind the valve. Pipe diameter > 50mm pipes may not be provided with unions

4. Branch pipe installation

4.1 check whether the installation position of the gas meter and the reserved opening of the riser are accurate. Measure the size of branch pipe and lamp fork

4.2 install the branch pipe, measure the size of the branch pipe, and then cut off the pipe, thread, bend and straighten the lamp. Put lead oil on both ends of the lamp fork or short pipe, wrap it with hemp, install the oil, connect the gas meter, and clean the hemp head

4.3 check the slope and parallel distance from the wall of the branch pipe with a steel ruler, a level ruler and a plumb bob, and recheck whether the riser and the gas meter move. Replace the gas meter with a branch pipe after it is qualified. The system pressure test and purging shall be carried out according to the pressure specified in the design or specifications. After the purging is qualified, the connecting pipe shall be removed and the gas meter shall be installed before handover. Go through the acceptance procedures after passing the inspection

5. Gas meter installation

5.1 the installation position of user metering device should meet the following requirements

5.2 it should be installed in the room with non combustible structure and good ventilation

5.3 it is strictly prohibited to install in bedrooms, bathrooms, dangerous goods and inflammable goods storage places, and places similar to the above situations

5.4 the metering devices for the production gas of public buildings and industrial enterprises should be set in separate rooms

5.5 the working environment temperature for installing the wax isolating meter should be higher than 0 ℃

5.6 the installation of gas meter shall meet the requirements of meter reading, overhaul, maintenance and safe use. When the gas meter is installed above the gas stove, the horizontal clear distance between the gas and the gas stove shall not be less than 30cm

5.7 before installation, the gas meter shall have a factory qualified owner and manufacturer's production license. The meter shall be tested by the legal testing unit, and the factory date shall not exceed 4 months. If it exceeds, it shall be tested by the legal testing unit. At the same time, there is no obvious damage

5.8 a gas meter should be installed in each household of residents, and at least one meter should be installed in each independent accounting unit for collective, business and institutional users

5.9 during the installation of the gas meter, it is not allowed to collide, invert, knock, and no rust, debris, oil and other substances are allowed to fall into the instrument

6. Pressure test of indoor gas pipeline

6.1 compressed air or nitrogen should be used for pressure test and purging of gas pipeline

6.2 test scope. The pressure test refers to the pipe section from the main valve of the air inlet pipe to the revolving valve of each stove connecting pipe. The gas meter is not included in the test, and a short pipe shall be used to connect the pipeline temporarily at the meter installation place. Tightness test, add all cooking appliances and equipment within the above range

6.3 the strength test pressure of the gas pipeline in the house is 0.1MPa (excluding the meter and stove). It is qualified if all joints are coated with soap liquid and there is no air leakage. Tightness test: observe with 7000pa pressure before installing the meter for 10 minutes, and it is qualified if the pressure drop does not exceed 200Pa. After connecting the gas meter, observe with 3000pa pressure for 5 minutes, and it is qualified if the pressure drop does not exceed 200Pa

6.4 strength test pressure of gas pipelines in public buildings: 100KPA for low-pressure gas pipelines (excluding meters and stoves). The medium pressure gas pipeline is 150kPa (excluding meters and stoves). It is qualified if all joints are wiped with soap liquid and there is no air leakage. Tightness test: the test pressure of low-pressure gas pipeline is 7000pa, and it is qualified if the pressure drop does not exceed 200Pa after 10min observation. The pressure of medium pressure gas pipeline is 100KPA, and it is qualified if the pressure drop does not exceed 1.5% after 3H observation. The gas meter is not subject to strength test, but only to tightness test. The pressure is 3000pa, and it is qualified if the pressure drop does not exceed 200Pa after 5min observation

7. After rust removal of indoor gas pipelines and accessories, brush one layer of antirust paint and two layers of silver paint

8. Installation of household stoves

9. Installation of stoves for public building users

the installation of natural gas is almost completed here. Of course, there are some details, because the small series of data is limited, the small series is not so clear. For more information about the installation of natural gas pipelines, please continue to pay attention to the information

南京皮肤病医院

大连性病医院

兰州银屑病医院

哈尔滨牛皮癣医院

Copyright © 2011 JIN SHI