Shanghai Songjiang Vibration Absorber Co., Ltd. official website brings you information: The first thing after the production of new rubber expansion joints is pressure testing. Songjiang Group has produced a new type of rubber expansion joint, adopting a new appearance and applying for a design patent. The appearance design of this new type of rubber expansion joint is exquisite, and the flange material is made of QT450, which has toughness, strength, and is not easy to rust.
Songjiang Group made a public appearance at the Shanghai International Pump Pipe Valve Exhibition in June 2018:
Mass production for random sampling:
In order to simulate the most realistic on-site usage scenario, we used large-diameter flat welding flanges and welded heads on them, which appear to be blind plates, but are actually modifications of large-diameter flat welding flanges.
The new type of rubber expansion joints can be clearly distinguished from the appearance, and the rubber sealing surface has also been redesigned, which is much better than the original. The flange also adopts a new material, QT450, which is ductile iron. This material increases the toughness and plasticity of the flange, and is not easy to rust, thus extending the service life compared to traditional materials.
Our factory’s quality inspection department has its own testing standards. For small diameters below DN200, pressure testing is allowed to reach 16kg without adding limiters. When the water pressure reaches 10kg, the length of the rubber joint itself will change. Under the natural state of 16kg without limiters, the rubber joints with a diameter of DN200 will elongate by 20mm to 30mm. This experiment is called a mandatory test, which means that even after the product itself exceeds the elongation range, there is no leakage or explosion. Only then can customers be more assured to use it within the allowable range. All rubber joints produced by Songjiang Group require the addition of limiters to fix the rubber joints within the allowable length range for normal pressure testing, which can detect up to 1.5 times the pressure. Sometimes, without limiters, rubber joints may leak due to excessive length, or because the bolts are not tightened evenly. It’s difficult to control. Adding limiters eliminates many concerns.
