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Gaskets - How do they work and why do we need them?
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Gaskets - How do they work and why do we need them?
The scope of this presentation is to present basic information and understanding of the ASME code for the design of pressure vessels for the chemical and process industry as applicable in the United States and most of North and South America.Get more news about Flange Metallic Gasket,you can vist our website!
Gaskets – How do they work and why do we need them?
If you are a fabricator, one of the last things on your list is ordering the gaskets. If you are an Engineer, the last thing on your list is specifying gaskets. If you are an owner and you hare having a problem sealing flanges, the number ONE thing on your mind is gaskets.Many times, they look like a sheet of paper. They can have metal or graphite rings. They can be carbon steel or stainless steel. They can be big or small. But if you don’t have them, it is a tough life in the refinery, chemical plant or in the field.
The cost of leaky joints in industry today is staggering. Out-of-pocket costs run into billions of dollars annually in lost production, waste of energy, loss of product and, most recently, impact on the environment. These problems are increasing, not decreasing. It behooves all of us to consolidate our knowledge and experience to solve or at least minimize these problems. Too often we find insufficient time and attention has been given to:
Selection of the optimum gasket material required to solve a particular sealing problem.
We will endeavor to outline those areas we believe to be essential in a properly designed, installed and maintained gasketed joint.We believe most people involved with the design, installation, and maintenance of gasketed joints realize that no such thing as “zero” leakage can be achieved. Whether or not a joint is “tight” depends on the sophistication of the methods used to measure leakage. In certain applications the degree of leakage may be perfectly acceptable if one drop of water per minute is noted at the gasketed joint. Another requirement is that no bubbles would be observed if the gasketed joint was subjected to an air or gas test underwater. A still more stringent inspection would require passing a mass spectrometer test. The rigidity of any test method would be determined by:
Care in these areas will ensure that the best technology and planning goes into the total package and will minimize operating costs, pollution of the environment and hazards to employees and the general public.Why Gaskets are Used
Gaskets are used to create a static seal between two stationary members of a mechanical assembly and to maintain that seal under operating conditions, which may vary dependent upon changes in pressures and temperatures. If it were possible to have perfectly mated flanges and if it were possible to maintain an intimate contact of these perfectly mated flanges throughout the extremes of operating conditions, a gasket would not be required.
As a consequence, relatively inexpensive gaskets are used to provide the sealing element in these mechanical assemblies. In most cases, the gasket provides a seal by utilizing external forces to flow the gasket material into the imperfections between the mating surfaces. It follows then that in a properly designed gasket closure, three major considerations must be taken into account in order for a satisfactory seal to be achieved.