Correct installation is very important to the PVC-C piping system. In order to ensure that the system can operate safely for a long time, some installation instructions and precautions for piping installation will be introduced below.
1. General installation process
During transportation and installation, attention should be paid to avoid pipeline damage. During transportation, it should not be transported with metal pipelines, and should not be dropped or dragged anywhere, especially in cold areas; PVC-C accessories should be treated the same.
Before the formal installation, the pipeline should be carefully inspected for cracks, bulges or other damages, especially the inspection of the inner surface of the pipeline. Sometimes due to improper handling, problems occur on the inner wall of the pipe and the outer surface remains intact.
According to the cutting guide below, PVC-C pipes are very easy to be cut. It is best to choose a saw blade with fine serrations (6-8 serrations per centimeter), and there should be no lateral extension; if a circular electric saw is used, the speed should be about 6,000RPM, if a blade saw is used, the speed should be 18m/ Seconds; when manually cutting, in order to achieve the vertical cutting effect, it is best to have direction control measures; after cutting, please clean the sawdust and oil stains on the pipe surface.
Installation methods There are many installation methods for industrial PVC-C, such as solvent bonding, flanges, threaded connections, and welding. At the same time, PVC-C pipes can also use hot-melt connection and VICTAULIC method, but they are rarely used.
4. Pipeline hoisting/buried
industrial PVC-C can be installed on the ground or underground at the same time.
5. System stress
Any metal or non-metal piping system will be subject to stress-induced damage, so special attention should be paid to the stress of the entire system. The total stress on a piping system includes not only the known pressure stress, but also the stress generated during expansion or installation. Expansion rings or joints can minimize the expansion stress, and careful installation can minimize the installation stress . When bonding pipes, pipes and fittings should be ready at any time, hangers and brackets should have an appropriate distance to avoid sagging, hangers should not be cut into the pipe or clamped too tightly, and system fittings should not be forcibly inserted.
6. Thermal expansion
Compared with other thermoplastic pipes, industrial PVC-C has the lowest thermal expansion coefficient, but it is still much higher than that of metal pipes. Usually in the design, expansion rings or brackets are used to compensate for thermal expansion, and expansion can also be used. Connector.
7. Test of the
piping system After the piping system is installed and the adhesive is completely dry, the system should be pressure tested and checked for water leakage. It is not recommended to use compressed air or nitrogen for testing. All the air in the system can be exhausted when the system is full of water. The water injection speed should not exceed 0.3 m/s. After filling, the system should be pressurized to 125% of the maximum design value of the lowest part of the system. When checking whether the system is leaking, the pressure should be maintained for 1 hour.
2. There are several commonly used connection methods for industrial PVC-C piping systems.
PVC-C industrial pipes can generally be connected by adhesive connection, threaded connection, flange connection and welding connection. The following three commonly used connections will be introduced in detail.
1). Adhesive connection of
pipes. The scope of application of pipe adhesive connection: when the adhesive connection is widely used in PVC-C piping system, the connection of pipes and pipes and the connection of pipes and fittings;
the steps of pipe adhesion connection:
(1 1) Manual saw or cutting machine should be used for pipe cutting, entanglement is not allowed; when manual cutting, in order to achieve the vertical cutting effect, it is best to have direction control measures;
(2) The cut ends of the pipe should be cleaned of chips and burrs, and be lightly chamfered outside the end surface. The chamfer should be 15°~20°;
(3) Wipe the connecting end of the pipe and the fittings with a cleaning cloth. If there is oil on the part, it should be wiped with a cleaning agent;
(4) When the pipe and the fitting are sleeved, the joint surface needs to use a cleaning agent. The smearing equipment is about half the diameter of the pipe. The smearing tool or brush is very suitable. Use a rag. The cleaning cloth should coat the outside of the end of the tube and the inside of the fitting sleeve. If necessary, increase the amount of coating to ensure the surface joint;
(5) Try to insert the pipe into the socket until it cannot be inserted, and mark on the pipe. Insert the depth marking line, the trial insertion depth should be 1/3~3/4 of the socket depth, and mark the socket depth marking line
on the pipe ; (6) The adhesive must be applied after the cleaning agent on the pipe surface is completed. Instead of applying it when wet. The adhesive should be brushed with a bristle brush or nylon brush, and the width of the brush should be 1/3~1/2 of the pipe diameter. Coat the socket first, then the socket (when Dn≥75mm, two people should paint the socket and socket at the same time), and apply axially, repeat 2~3 times. The brushing socket should be from the inside to the outside, and the brushing socket should be from the depth mark of the socket to the end of the pipe;
(7) The tube coated with adhesive should be inserted quickly (make sure the bonding surface is wet when inserting) until the bearing Mouth depth markings. Do not use a hammer to knock in. When the pipe diameter is greater than 75mm, mechanical insertion should be used and the straightness of the socket interface should be ensured.
(8) After reaching the insertion holding time, wipe off the excess adhesive with a cloth and let it stand for 15 minutes;
(9) The bonding operation should not be performed in a low temperature environment below 0°C.
2. Threaded pipe connection
1) Scope of use of pipe threaded connection: generally used for the connection of CPVC pipes with other types of pipes, valves, and instruments; when regular disassembly is required, you can use roulette, flange and direct.
2) The threaded connection of the pipeline should meet the following requirements:
(1) When the pipe diameter is not greater than 110mm and the working temperature does not exceed 54°C, the threaded connection can be used;
(2) The working pressure of the threaded connection is 50% of the adhesive connection at the same temperature;
(3) The threaded connection should use PTFE raw material tape as the filler, and no hemp or thick white paint should be used.
(4) After wrapping the PTFE tape, screw the pipe to the pipe. If necessary, use special tools, such as a pipe wrench or a wrench, to tighten the threads.
3. Pipeline flange connection
1) The scope of application of pipeline flange connection: generally used in the connection of PVC-C pipes with other types of pipes, valves, and equipment, and the pipeline system needs temporary maintenance and disassembly or cannot be bonded at the installation site When connecting;
2) The steps of pipe flange connection:
(1) Bond the CPVC pipe and the CPVC flange joint according to the above method;
(2) The CPVC flange hole should
Link to this article：Industrial PVC-C pipe installation guide
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