Gaskets
Gaskets
Able Industrial and Marine Sales has a complete gasket fabrication shop, handling most of the major manufacturers of gasket material. We customize gaskets to your tolerances.
AIMS offers non-asbestos gaskets, asbestos gaskets, rubber gaskets, graphite gaskets, teflon gaskets and more. We stock standard rings, full face gaskets, standard spiral wound gaskets, and can provide double jacketed gaskets and other special gaskets.
We fabricate gaskets for most applications including:
Our knowledgeable associates will be glad to help you choose the correct material to meet your requirements. With excellent pricing and service AIMS can help you compete and win in your industry
SPIRAL WOUND GASKETS
DEFINITION AND FUNCTION OF SPIRAL WOUND GASKETS
A gasket is a deformable material, which when clamped between essentially stationary members, prevents the passage of matter through or across the gasketed joint.
Joint and gasket design must be considered conjunctively. A leak-tight assembly depends upon successful interaction between the surfaces to be sealed, the gasket, the bolting or clamping force, and its environment. The gasket is but one component of the joint system and its selection is based upon matching its characteristics to those of the other components.
The gasket must deform and fill surface irregularities to effect a pressure boundary. it must be capable of maintaining this boundary for the intended life of the joint. A successful gasket selection must consider the following criteria:
SELECTION CRITERIA
TEMPERATURE: Gaskets are affected in two ways by temperature. Gross physical characteristics are determined by temperature, including material state, oxidation point, and resilience. Secondly, mechanical (creep or stress relaxation) and chemical properties are highly temperature dependent.
PRESSURE: Internal pressure
acts in two ways against a gasket. 
The hydrostatic end force, equal to the
pressure multiplied by the area of pressure boundary, tends to separate the
flanges. This force must be opposed by the flange clamp force. The
difference between the initial flange clamp force and the hydrostatic end force
is the residual flange load. The residual load must be positive to prevent
joint leakage. The magnitude of the residual flange load required to
prevent leakage is dependent upon the style of metal gasket selected and its
material construction. Secondly, the pressure acts to blow-out the gasket
across the gasket-flange surface.
FLUID COMPATIBILITY: The gasket must be resistant to deterioration from corrosive attack. The severity of attack and resulting corrosion is dependent upon temperature and time.
FLANGE COMPATIBILITY: The gasket is intended to be the renewable component in the joint system therefore it should be softer or more deformable than the mating surfaces. It must also be chemically compatible. For metal gaskets, this means consideration must be given to galvanic corrosion. Galvanic effects can be minimized by selection metals for gasket and flange which are close together in the galvanic series, or the gasket should be sacrificial (anodicaaaaaa0 to prevent damage to the flanges.
JOINT DESIGN: There must be sufficient clamping force to seat the gasket and to prevent flange separation due to confined fluid pressure. The flange must be sufficiently rigid to prevent excessive bending which would cause localized unloading of the gasket. Flanges using full face gaskets must be thick enough to prevent bowing between adjacent bolts.
SURFACE FINISH: Each gasket type works best when the flange contact faces have a specific surface finish. Surface finish requirements differ with gasket type and must be considered. Consult with the manufacturer for the proper surface finishes.
SEATING STRESS: Gasket sealing is accomplished by the flow of the gasket material into machines surfaces on the flange facings. The amount of force per unit of gasket area required to completely flow the gasket is known as yield or seating stress. This stress varies with gasket type, material and flange surface finish. Minimum seating stresses given in Tables 2-5.1 of the ASME Boiler and Pressure Vessel Code are values that have been established empirically and result in satisfactory flange design for pressure vessels. The design calculations ensure that the resulting flange thickness, size and number of bolts will provide a joint of adequate rigidity and clamping force to contain the maximum design operating pressure of the vessel gasket. The design includes a margin of safety of approximately 4:1. It is important to note that theses design criteria do not dictate the actual flange bolt loading and resulting gasket seating stress in operating conditions. New gasket constants and design methodology are expected to appear in upcoming editions of the ASME Code. The new constants will be based on testing by the Pressure Vessel Research Council. Effective sealing depends on many inter-related factors: pressure, temperature, type of fluid contained, flange surface finish, flange alignment, gasket type, etc. Operating factors such as thermal cycling, vibration and thermal shock must be considered. It is recommended that the operator of the equipment consult with the gasket manufacturer for bolt load recommendations for specific gasket style and operating conditions.
FLANGE FACINGS: There are many types of flange facings in use. But, the majority of these fall into one of the following three groups:
1. Unconfined: Best for all non-circular and large circular shapes.
2. Semi-Confines: For circular shapes and accurate location of gasket.
3. Fully Confined: These flange facings are used for circular shapes, with narrow gaskets at thigh pressure.
Other special flange facings are those which use the Bridgeman closure, the lens ring,
5617 Salmen Street Harahan, Louisiana 70123
Phone: (504)733-2601 Fax: (504) 734-7364
Email: inquiries@ableindustrial.com