SIC 3053 Gaskets, Packing, and Sealing Devices
SIC 3053
This category covers establishments primarily engaged in manufacturing gaskets, gasketing materials, compression packings, mold packings, oil seals, and mechanical seals. It includes gaskets, packing, and sealing devices made of rubber leather, metal, asbestos, and plastics.
339991
Gaskets, Packing, and Sealing Devices
A seal is a device used to control or eliminate leakage of liquids or gases while simultaneously preventing the entrance of contaminants from the external environment, such as dirt and dust. Seals are divided into two classifications: static or dynamic. Static seals are used on surfaces where there is no relative motion between the surfaces. An example of a static seal would be an engine cylinder-head gasket. Dynamic seals are used wherever relative motion exists between two surfaces, either intermittently or continuously. Examples are engine crank-shaft seals and hydraulic cylinder-rod seals.
There are several basic types of seals. Cup-packings are mainly used as piston-head seals. Previously made from leather, elastomers are now used for low-pressure, smaller cups, while an elastomer/fabric blend is used for high-pressure applications. Cup-packings are particularly effective where clearance between surfaces to be sealed is excessive—for example, when sealing rough metal surfaces.
Gaskets typify the compression-sealing method. They are made from a wide variety of materials, often used in combination with one another. For example, cork and elastomers are a popular combination in automotive usage because cork's compressibility and rubber's resiliency combine to give excellent results in such uses as engine gaskets. Gaskets can be molded or cut from a sheet. They are installed between two surfaces, and pressure from bolting or clamping provides the sealing force.
Elastomeric gaskets are the most common type of nonmetallic gasket. They can be made of synthetic rubber or thermoplastic elastomers (TPEs)—materials that have properties similar to rubber but are processed like plastics. Elastomeric gaskets are produced in a variety of sizes, colors, and finishes. They also can be produced to be especially resistant to such things as temperature, oil, chemicals, weathering, aging, and abrasion. With all these variations, as well as the variety of elastomers available, the applications vary tremendously. Simple applications would include such things as plumbing gaskets, while other, more sophisticated gaskets find advanced applications in aerospace products.
The simplest and most common sealing device, the O-ring, is used in numerous systems. O-rings can be used in static and dynamic applications, depending on the proper design. Among their primary uses are as components in automotive steering and brake systems, off-road heavy equipment, aircraft, and other industrial and household items.
Mechanical face seals are a multicomponent sealing device used to create a leakage-free seal between a rotating shaft and a member through which the shaft passes. They are used in automotive water pumps and in the chemical process industries.
Molded packings and seals are mainly used in such things as fluid handling pumps, valves, cylinders, piston-type accumulators, and other equipment. They can be used as seals on the rod, ram, piston, plunger stem, or spool to develop and maintain hydraulic working power. They find their main applications in static sealing uses. Molded seals include squeeze-type ring seals and lip types. Squeeze seals are used in low-pressure applications, with lip seals finding more usage in high-pressure needs.
Radial lip seals are used in dynamic, low-pressure applications. Many are available in standard sizes, but the trend is to customize production.
U-packings are pressure-activated sealing devices commonly used in low to moderate dynamic sealing applications. They can be found in such things as pneumatically or hydraulically activated door openers.
Three or more seals are often used together in the low-speed...
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