As we near year-end of 2020, this year has already proven to be one of the most challenging in many decades. To help make things more positive, our manufacturer MTI is releasing articles assisting in different seal points, and Power Dynamics has these items availabe to ship!
What is a “V-band clamp”?
V-band clamps are clamping mechanisms used in joining two cylindrical “pipes” together in place of a heavier, bolted joint. Also referred to as “Marmon joints”, these designs are most commonly used in diesel exhaust systems to connect pipe sections together. This design is particularly useful in this application because the DPF (diesel particulate filter), SCR (selective catalytic reduction), and other components need to be disassembled for occasional service. This design makes it easy to perform this maintenance using these types of joints.
How does it work?
The clamps provide loading to a flange when tightened around it. The “V” section provides increasing force up to its design load; however, overloading the clamp leads to stress damage and misalignment, and a general and permanent failure of the seal point. Flanges can be flat or angled, rough or machined, stainless or carbon, etc. In general, this clamp style joint provides less sealing stress than a bolted joint. Since the exhaust piping does not require a high-pressure seal, it is generally sufficient when designed and installed properly.
In many applications, the component “fit” does not allow the joint to seal even when the clamp is used as per the manufacturer’s instructions. The metal shim inserts used are insufficient to provide the initial seal of the joint system and leads to leakages and ultimately a catastrophic failure in the system. Our design and products provide a much wider tolerance range and corresponding success than the Marmon designed metal shims.
What do I seal it with?
Materials can vary by application, but generally these are for hot gas/exhaust joint applications. To handle the heat and low sealing loads, the Hi-Tex products are recommended due to their robust steel core and high temp facings. By working with OEM design teams, MTI has had successful results with both the HT 400 and HT 195 products in the OEM joints. Moreover, they have successfully used Metal Tech Industries engineered designs to replace the metal shim insert designs by others. This change alleviates a very large warranty costs and customer satisfaction issues for many applications.
The HT 400 is designed for gaskets under elevated temperature conditions, while the HT 195 has excellent sealability under a variety of environments. In both cases, a stainless steel core is available if corrosion exposure is a concern. As with all designs, they should be tested and validated by the end user, and clamps should be installed per the manufacturer’s recommendations.