The majority of manufacturing sectors, including the automotive, aerospace, electronics, appliance and military industries, utilize gaskets in their production methods. Made of deformable material, a gasket is a sealing device usually designed in the form of a ring or sheet. They create a pressure-tight seam between multiple stationary components, relying on a compression seal to prevent unwanted gas or liquid emissions. Often times, these seals are intended to be resistant to pressure, temperature fluctuations and in some instances, electrical or electromagnetic forces. A gasket uses compression, so it is generally more malleable than the components it joins and is able to conform to the shape of the harder surfaces between which it is placed.
Since gaskets are available in a large number of specifications, making appropriate gasket selection is an important step in many manufacturing processes. A wide range of materials can be formed from gaskets, such as metals, rubbers, plastics, corks, foams and composite substances. They also come in a variety of designs, including jacketed, double-jacketed, spiral wound and Kammprofile varieties. Selecting the right combination of material and design depends on the gasket’s specific uses and the cost parameters of the project.
Is a Gasket Necessary?
Gaskets serve an important function as sealing joints, but there are a few similar devices that may be better-suited to certain tasks. Applications which require a seal that forms a barrier between external and internal elements, such as a unit to prevent water leakage, typically need a gasket. However, to fill small assembly gaps between components, manufacturers would be better served by a space, or “shim,” which is a narrow wedge used for packing or leveling purposes.
While similar to gaskets, o-rings, have a subtly different designation. O-rings, unlike gaskets, are made almost exclusively of synthetic rubber or plastic polymers with elastomeric properties, and are produced solely in ring form. By creating a barrier around an area with leakage potential, o-rings are extremely durable and reliable in sealing matched components. Additionally, o-rings are distinct for their round or square cross-sectional configurations, as well as their high pressure resistance, which makes them valuable in some applications where a standard gasket’s resistance would not suffice.
Gasket Specifications
After determining gasket is the appropriate device you need for a given application, several other factors must be considered to select a well-suited design. There are a number of types of gaskets, though many share similar features and may be capable of handling related tasks. Some of the most common varieties of gasket include:
Jacketed Gaskets
Jacketed gaskets merge the efficiency and flexibility of soft gaskets (made of rubber or plastic) with the resistance and durability of an external metal coating. A single-jacket contains a soft filler with metal coverage along one face of the gasket. Double-jacketed gaskets have a fully coated metal facing, providing improved temperature, pressure and corrosion resistance. Other variations include corrugated jacketed gaskets and French Style jackets, which provide coating on either the inside or outside of the gasket.
Solid Gaskets
Generally, solid gaskets are formed of metal and are a relatively inexpensive alternative to jacketed gaskets. They contain high thermal and pressure resistance, though they require higher compression force to form a seal and are typically effective only against surfaces that are harder than the metal itself.
Spiral Wound Gaskets
Spiral wound gaskets are formed by combining metal with softer plastics or synthetic rubber in a winding shape. They are often reinforced with additional layers of metal without filler. The unique design of this gasket yields high thermal and physical stress resistance, coupled with flexibility and resilient sealing. These gaskets are frequently used in piping, pumping and heat exchange systems.
Kammprofile Gaskets
The Kammprofile design has a corrugated metal core covered with a malleable sealing material attached to both of its sides. This structure focuses physical stress onto the surface sealant, which creates tight seals along the gasket’s edges while retaining the device’s flexibility and strong tensile core. These gaskets offer reliable support in heat exchange systems and have improved cost-effectiveness due to their capacity for repair.
Metal Gaskets
Many types of gaskets are constructed from metal or a mixture of metal and non-metal materials. They are typically formed with aluminum, copper, nickel, steel, stainless steel or brass. A high level of thermal, corrosive and pressure resistance are provided by these materials, along with excellent durability and tensile strength. Conversely, metals require elevated amounts of compressive force to form a seal and have limited flexibility for multiple applications. As a result, metals are often used in combination with rubber or plastic compounds, otherwise known as soft fillers.
Rubber and Plastic Gaskets
Rubber contains elastomeric properties, so it is a popular material for gasket production. Rubber gaskets can form very tight seals within a wide range of applications since they can undergo a high degree of deformation without permanent damage or loss of attributes. Some types of rubber often used in gasket manufacturing include nitril, viton and neoprene. Certain polymers, such as thermoplastic elastomer, thermplastic rubber and polyvinyl chloride, display qualities simile to those of rubber and are also common in gasket production.
Silicone Gaskets
Because silicone displays strong resistance to extreme temperatures, it is a valuable gasket material. These gaskets can have operating temperatures that range between roughly -140° to 480°F. Additionally, silicone-based gaskets’ resistance to ultraviolet light makes them useful in outdoor settings, while their flame tolerance within a certain thickness range has applications in electronics and transit industries. They come in foam and sponge varieties, and can be reinforced with out materials to improve tensile strength or adjust thermal and electrical conductivity.
Compression Testing
A crucial characteristic for industrial gaskets is their capacity for tolerating compressive loads. Evaluations, such as the hot compress test, can be utilized to gauge a specific gasket’s ability to withstand various weights and temperatures. A gasket is usually placed between the exertion bolts of a hydraulic press. Temperature is increased, usually up to nearly 600°F, at an incremental rate over a given period of time while the press exerts constant load pressure on the gasket. If there are any decreases in material thickness, they are measured and used to asses the gasket’s effectiveness. Tests such as this can assist in choosing a gasket or deciding upon a given material or design configuration.
For more information on selecting the appropriate gasket, don’t hesitate to contact us here at Bryan Hose and Gasket with the link below!