pvc-m tube

PVC-M not only maintains the advantages of PVC-U pipes, but also adds the following advantages:

1、Excellent impact resistance

The flexibility of PVC-M pipes has been greatly enhanced, and good toughness has improved the impact resistance of the pipes, effectively resisting external impact during installation and transportation, and improving the resistance to external force damage of the pipes.

Taking dn200mm pipe as an example, in the drop hammer impact test at 0 ℃, the impact heights of PVC-U pipe and PVC-M are both 2 meters, but the impact weight of PVC-M is 10kg, while the impact weight of PVC-U is only 2kg. Obviously, the impact energy borne by PVC-M is much higher than that of PVC-U pipes, indicating that the toughness of PVC-M is much higher than that of ordinary PVC-U pipes.

The rapid impact test at 22 ℃ and 20m for PVC-M pipes is more convincing. The standard requires that the test be conducted at 22 ℃, with a drop weight of 3-30kg (taking dn200mm as an example, the impact weight reaches 20kg) and an impact height of 20m. The test requires that all specimens do not undergo brittle failure to be qualified, while PVC-U pipes do not have this requirement. After systematic comparative testing, it was found that all PVC-M pipes were ductile damaged after impact, with a small pit punched out on the outer wall of the pipe, and the pipe body was not damaged; But under the same conditions, PVC-U pipes undergo fragmentation after being impacted.

Although throwing, dropping, rolling, and dragging pipes are strictly prohibited in the technical regulations for plastic pipeline construction, they are inevitably subjected to external impact during actual loading, unloading, transportation, and installation. PVC-M can effectively resist external impact to ensure pipeline safety.

2、Excellent crack resistance and ability to withstand point loads

In practice, pipes are inevitably damaged, or stress concentration may occur due to poor laying. Pipes with poor crack resistance are prone to leakage and rupture, and brittle failure may occur due to crack propagation. Experience has shown that most accidents in PVC-U pipelines in the past were "low stress brittle fracture", which means poor resistance to stress cracking.

The resistance to point load and environmental stress cracking of PVC-M is significantly improved. If scratches are accidentally caused on the surface of the pipe, it will not affect the use of the pipe. In order to verify the stress cracking resistance of PVC-M, a hydraulic test was specially developed for notched pipes. The cut pipe test is to determine the degree to which the pressure bearing capacity and service life of the pipe surface are affected after damage. Firstly, a cut should be machined on the surface of the pipe, with a depth of 10% of the pipe wall thickness. Then, the test should be conducted according to the internal pressure bearing standard. Only if the test is qualified (without cracking) can it indicate that the quality of the pipe is qualified. This test is unique to impact resistant pipes (PVC-M) and is basically consistent with the principle of ISO13479 "Slow Crack Growth Notch Pipe Test" required for PE pipes. PVC-U pipes do not require this test.

The hydraulic test results of the cut pipe show that PVC-M has strong resistance to point load, stress cracking, and crack growth. The long-term strength of PVC-M (with notches) is not affected, and its reliability is high; PVC-U (with incisions) has a significant decrease in long-term strength and low reliability. Due to the reduced sensitivity of PVC-M pipes to cuts, safety hazards are eliminated, thus ensuring the long-term, safe, and reliable operation of the pipeline.