YDK FLANGED FLEXIBLE RUBBER EXPANSION JOINT | MODEL: VNM-16

The YDK flanged flexible rubber joint, Model VNM-16, is an important piping accessory that absorbs vibration, reduces noise, and compensates for misalignment that arises during the operation of water supply systems. With a highly elastic EPDM rubber body combined with ductile iron flanges on both sides, the product relieves mechanical stress and protects valves and pumps from cracking or pipeline leakage. This accessory is commonly used in water supply and drainage systems, fire protection systems, HVAC, and other industrial piping projects.

General information on the YDK VNM-16 flanged rubber joint

Product construction

This is a flexible rubber joint with flanges at both ends and a spherical expansion body, consisting of two main component groups.

• Flanges: Made of ductile iron, located at both ends of the joint, with bolt holes in accordance with the BS4504 standard, used to connect directly to the flanges of pipes, valves, or equipment at either end.
• Body: Made of EPDM rubber, with a spherical bulge in the middle, internally reinforced with an additional layer of reinforcing material to increase pressure resistance while retaining the necessary elasticity. The body allows the joint to flex in all 3 directions: axial, lateral, and slight angular misalignment.

Technical dimension table of the YDK flexible rubber joint (DN50 – DN500)

Functions of the flanged flexible rubber joint

Although simple in construction, the flanged flexible rubber joint plays an extremely important and indispensable role in piping systems, because of the following:

• Absorbs thermal expansion of the pipeline when the temperature of the fluid changes. This prevents large thermal stresses from acting on flanges, pumps, or other rigidly connected equipment in the system.
• Dampens and isolates vibration from pumps or machinery. It is usually installed directly at the suction and discharge ends of a pump to stop mechanical vibration from the pump being transmitted into the piping system, while also protecting the pump from stresses caused by the pipeline.
• Compensates for small installation misalignments between pipe sections or between a pipe and equipment, making installation easier when there are small errors in position or angle, without having to rework the pipe.
• Reduces noise transmitted through the pipeline, thanks to the vibration-absorbing properties of rubber. This is useful in residential and commercial buildings that require limited noise from mechanical and electrical systems.

Installation locations and operating notes for the YDK VNM-16 flanged flexible rubber joint

Common installation locations of the flexible rubber joint

• Install the flanged flexible rubber joint directly at the suction and discharge ends of the pump. This is the most common location; it isolates pump vibration from the main piping system and vice versa, protecting both the pump and the pipeline.
• Install the flexible joint where the pipeline crosses a settlement joint or expansion joint of a building, where the structure may move slightly over time or with the seasons.
• Install before and after heat exchangers, pressure vessels, or other mechanical and electrical equipment that may vibrate or expand thermally during operation.

Note: Do not install the flexible joint in a position where it must bear bending forces or axial tension beyond the manufacturer’s design limits. Pipe supports or hangers must be provided on both sides of the joint, to avoid the entire weight of the pipeline bearing on the rubber joint, because this component has far less load-bearing capacity than a metal pipe.

Operating notes for the YDK VNM-16 flexible rubber joint

• Do not operate above the nominal pressure PN16 or outside the permitted temperature range. EPDM rubber that is exposed for a long time to temperatures or pressures beyond its design limits ages quickly, loses elasticity, and risks cracking or abnormal blistering at the spherical body.
• Periodically check the rubber body for abnormal tension or deformation during operation, especially at locations near pumps with continuous vibration. If the spherical body is found bulging to one side, cracked on the surface, or leaking at the connection with the flange, stop operation and inspect or replace it promptly.
• Avoid direct contact between the joint and mineral oils and greases, organic solvents, or chemicals incompatible with EPDM rubber. These substances can swell or break down the rubber structure, causing it to lose its sealing and pressure-bearing capability.
• Re-check and re-tighten the flange bolts as part of the periodic maintenance cycle, especially after the initial operating period when the rubber may relax slightly as the material settles, ensuring even tightening force around the whole flange circumference to avoid local leakage.

The YDK flanged flexible rubber joint is an important link that protects the entire piping system from the risk of failure caused by vibration and shock. Choosing genuine products is therefore a priority for many contractors. An Phu Thanh is proud to be a reputable importer and distributor of genuine YDK valves and accessories in Vietnam, in a wide range of sizes and types.

If you are a customer or project owner looking for the best quotation for the YDK VNM-16 flexible rubber joint, please contact An Phu Thanh via Hotline 0946 729 913 for detailed consultation today!