Seals Suported by

Introduction A seal is a piece of material or method that prevents the flow of a fluid between two surfaces. The surfaces can be stationary or have movement between them. Suported by

Seals Functions 1. Prevent the leakage of lubricant; 2. Stop the flow of dirt and foreign material into a system; 3. Keep fluids like lubricant and water apart; 4. Be flexible enough to prevent leakage when there is small movement between parts; and 5. Seal rough surfaces and wear faster than the parts they are used with. The parts cost much more to replace than a seal would. Suported by

Basic Types of Seals There are two basic types of seals: Static seal – A seal in which there is no movement between the two sealed surfaces. Dynamic seal – A seal that is used between surfaces in which there is movement of the sealed surfaces in relation to each other. Suported by

Types of Seals Suported by

Gaskets Gaskets are static seals made of deformable (elastic) material. Gaskets are made in all shapes and sizes but normally are flat and shaped like the surface sealed. Gaskets are generally made from cork, metal, paper, asbestos, rubber, or a combination of these. Suported by

O-ring Seal An O-ring or seal is a smooth round ring made of natural rubber, synthetic rubber (man-made), or plastic material. Most O-rings have a black color but other colors are also common. O-rings generally have a part number shown on the ring. O-rings normally have a round cross-section but can be shaped differently. An O-ring can be used as a static seal or a dynamic seal to prevent the movement of liquids or gases between two round parts. Suported by

Lipe-type Seal There are many types of lip-type seals. A typical lip-type seal is made of several parts. An outer shell (covering) is used for support and installation alignment. Inside the shell is a flexible sealing element formed into a lip. Many times there is a "garter" spring to hold the lip against the surface to be sealed. Lip-type seals are available in many sizes and designs. Lip-type seals are low-pressure, dynamic seals found in applications where a rotating shaft needs sealing. Suported by

Wear Sleeve A wear sleeve is a round, steel, thin-walled ring. One end of the sleeve is tapered to help the installation of the seal that fits around the outside of the sleeve. Wear sleeves are available in sizes that range from about .75 to 7.5 inches (1.91 to 19 cm) in inside diameter. The width is generally determined by the width of the seal used. Use of a wear sleeve is a low-cost way to repair worn shafts. The wear sleeve is pressed on the worn shaft and a new seal of the correct size is installed over the sleeve. Suported by

Duo Cone Seal The Duo-Cone® seal is made of two "toric" rings and two metal rings. The "toric" rings are similar to large O-rings and they are installed in a groove around the metal ring. The surface of the metal rings is machined and lapped to form a smooth "metal to metal" seal. Duo Cone seals are a very special type of seal. The seal is designed to keep large amounts of dirt out and keep lubricants in. Suported by

V-type and U-cup Packing Rings The two types of packing rings are the V-type and the U-cup type. A cross-section of the ring will show that it is shaped like a V or a U. Several V-type rings are used together to form a seal. Only one Ucup seal is used to form a seal. Packing rings are usually black in color and made of synthetic material. Packing rings are usually used in high-pressure dynamic applications.Compression of the ring causes the expansion of the inside and outside lips of the ring. Suported by

Metal-backed Seal A metal-backed seal is very similar to an O-ring. A spring steel case (cover) outside supports the sealing material, which is usually a synthetic-rubber like material. Metal-backed seals are used in the same static applications as O-ring seals especially where high or low temperatures are experienced. Suported by

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