1, clamping connection
Divided into single card pressure and double card pressure. Double card pressure is the most stable connection mode. The external force (hydraulic tongs) contracted radially is used to clamp the pipe fitting on the pipe, and the connection effect is achieved by sealing the O-ring. Convenient operation, good sealing and non-disassembly.
2. Ring-expanding connection
The pipe fitting is clamped on the pipeline by radial contraction external force (hydraulic tongs), and the connection effect is achieved by sealing the water with the wide-band rubber sealing ring, which is detachable. When installing the pipeline, the process of rolling the convex ring at the pipe end is added. The sealing property is general, and the cost of casting pipe fittings is high.
3. Welding joint
The two connectors are fused by hot melt process to achieve the connection effect. The connection strength is high, and the welding gas protection at the field welding joint is difficult to meet the standard, which leads to the rust of the weld and directly reduces the service life of the pipeline; The installation quality is highly dependent on the welding workers' skills, and the quality is difficult to stabilize.
4. Self-locking connection
It was first used to connect small-caliber plastic hoses, and it can be quickly installed without tools. The interior of the interface is easy to loosen and leak, and the sealing performance is poor.
Second, how to install stainless steel water pipes
1, material acceptance
Pay attention to the strict inspection before the drainage pipe is installed. The internal and external walls of the drainage pipe should be smooth and level, without bubbles, cracks, depressions, peeling, serious cold spots and obvious traces.
2, on-site disclosure
The installer should read the drawings carefully, confirm the location of facilities and equipment, and find out whether the owner or designer has any special requirements. If there are special requirements, the construction shall be carried out according to the instructions of the owner or the designer.
3, pipe cutting
The installer should measure the length of the pipe required for cutting. The pipe is cut by special pipe, and the whole section of the fracture is burr-free.
4. Pipe connection
Stainless steel water pipes and fittings are connected by hot melt, which is the most reliable, convenient to operate, good in air tightness and high in joint strength. Dust and foreign matter on pipes and fittings shall be removed before connection. Pipes and fittings should be heated by welding machine, and the depth and time of hot melting between pipes and fittings should meet the requirements. Do not rotate during hot melt welding. When connecting threaded fittings, the raw material belt should be wrapped to ensure sealing.
5, pipe fixation
In order to ensure that stainless steel water pipes will not vibrate due to water pressure in future use, all stainless steel water pipes must be fixed with pipe clamps. Pipe clamps should be set at the corner, water meter and pipe end of the pipeline, with the spacing of 400-500mm and the outer diameter less than 25mm. Under special circumstances, the thickness of mortar landfill layer should be greater than100 mm.
6. Inhibition test
After the installation of stainless steel water pipes, pressure test should be carried out. After installation, all internal curved pipelines shall be equipped with baffles or triangle valve to ensure sealing. Water pipe pressure test is a test to ensure the quality of drainage pipeline and installation quality. The pressure test of drainage pipeline is to pump the pressure ≥0.6MPa into the pipeline, and the pressure measurement time is not less than 30 minutes, and the pressure drop is less than 0.05Mpa.
Three. Precautions for installation of stainless steel water pipes
1, pay attention to cover with anticorrosive materials.
Even the best stainless steel water pipes should not be in direct contact with cement and concrete during installation and laying. When the pipeline is concealed, the outer wall of the pipeline should be wrapped with anticorrosive tape or plastic-coated thin-walled stainless steel pipe, or two layers of polyethylene tape or vinyl chloride tape should be wrapped around the stainless steel water pipe, and then two layers of asphalt paint and glass fiber plastic cloth should be wrapped for anticorrosion, which can help the stainless steel water pipe resist more serious natural corrosion.
2, set up the compensation device
When laying stainless steel water pipes, expansion compensation devices and supports, fixed supports or movable supports should also be reasonably arranged to control the expansion direction or compensation of the pipes.
3. Pay attention to the collocation of accessories
When installing the first-class stainless steel water pipe, we must also pay attention to the use of matching accessories, and do a good job of pipes and fittings provided by the same supplier to avoid welding difficulties caused by differences in data specifications between different models, so this is also something that project engineering enterprises should pay special attention to.
Many engineering stainless steel water pipes are laid in bare positions, so it is necessary to take corresponding dew prevention measures and pay attention to the heat preservation of the water pipes to avoid freezing phenomena such as supercooling of the stainless steel water pipes, which makes water supply difficult; In addition, when installing and handling stainless steel water pipes, avoid collision with sharp objects, so as to avoid water leakage caused by pipeline damage, and pay attention to it during construction. In particular, it should be reminded that after the pipeline is installed and the pressure test is qualified, it should be disinfected with disinfectant.