As noted in the Elastomeric Flex Connector section, all connections to isolated pieces of equipment must be flexible. Having resolved most of the inherent design flaws in the market-available elastomeric connectors, at the time, by redesigning, engineering and coming out with their own Elastomeric Flex Connectors, Mason was then forced to turn their attention to Metal Flex Connectors because they were getting calls claiming that the vibration isolation product that they had supplied to isolate various pieces of equipment was not working effectively. Upon investigation, invariably, they found that the Metal Flex connections to the equipment were the root cause of the problem. Simply changing out the ‘Metal Flex’ with their Elastomeric Connectors resolved the issue in most instances. However, there were many applications where, for process/system reasons (ie: corrosive fluids, gaseous applications or when temperatures and pressures were out of the design range of Elastomeric Connectors), only Metal Connectors could be used.
So the question was; ‘why were these metal connectors not performing well in reducing vibration from equipment to piping?’. What they found was that most of the manufacturers were largely designing their connectors to flex so that piping forces and misalignments would not get transmitted to the equipment. These forces could cause casting cracking or fracturing of the piping and, hence, mitigating these forces was the basis of the design. Vibration Isolation really wasn’t ‘on their radar’. Compounding the problem was the fact that these manufacturers would buy the raw corrugated metal ‘hose’, which had tight ‘closed pitch’ corrugations, and stretch it into an ‘open pitch’ so that they could get a much higher yield of connectors, thus gaining significant competitive cost advantage. Further, in a vast number of instances, misalignment and superimposed forces, though potentially catastrophic if not addressed, were nominal. So they were able to reduce the effective length of the connectors, again to cost advantage. Their product still worked well to deal with the prime objective of the connector’s designed function but that design became totally ineffective in dealing with vibration traveling from equipment into piping. As a result, as with Elastomeric Connectors, Mason decided to design, engineer and market their own Metal Flex Connectors, solely based on addressing vibration isolation of the equipment from piping issue. This involved using ‘closed pitch’ (greater number of convolutions per inch) hose and establishing, through testing’, the most effective length to achieve acceptable vibration isolation. Ironically, even in shorter lengths, theirs were more effective than the standard Metal Flex Connectors on the market in dealing with misalignment, expansion/contraction and mitigating pipe forces to the equipment. So, Mason made shorter lengths available to the market for those applications. However, in seismic areas, only the longer lengths should be used, if not Seismic ‘V-loops’, which incorporate 2 long length, ‘closed’ pitch connectors, set at an appropriate angle to each other, in the assembly, such that large movements in all three planes is accommodated during a dynamic event. For more detailed information about the evolution of these connectors please click here