Monthly Archives: August 2017

Classifying the Types of Seals

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Depending on the direction that squeeze is applied to the O-rings cross section on a seal, it will be categorized as an AXIAL or RADIAL seal.

Static Axial Seals

A static axial seal will act in a similar manner to a gasket that is squeezed on both the top and the bottom of an O-ring’s cross section. A static axial seal is used in face (flange) type applications. When it is used as a face seal and there is internal or external pressure, the O-ring should be positioned against the low-pressure side of the groove to cut down on O-ring movement and accompanying wear within the groove.

These seals are easier to design than static radial seals since there is no extrusion gap and fewer design steps. This enables you to control the tolerances more easily.

Static Radial Seals

Typically used in cap and plug type applications, static radial seals are squeezed between the inner and outer surface of the O-ring.

Static Crush Seals

The O-ring is confined and pressure deformed (crushed) within a triangular gland which is made by machining a 45-degree angle on the male cover. In crush seal applications, the seal is squeezed at an angle to the O-ring’s axis.

Static Seals with Dovetail Glands

Sometimes O-rings are used in static or slow moving dynamic situations where a specially machined “dovetail” gland needs to be used. Controlling tolerances in the glands can be difficult because of the angles involved. The glands are meant to securely hold the O-ring in place while the machine is in operation or during maintenance and disassembly.

The O-ring squeeze is mostly axial in direction and valve operations puts force on the top and bottom seal surfaces. So that there is no tearing or nicking, the use of an O-ring lubrication is recommending while the O-ring is being installed into the dovetail gland. It is difficult to create the groove and tight tolerances are required so this type of seal application should only be used when necessary.

Reciprocating Seals

Reciprocating seals are used when there is a moving piston and rod. This is the most common dynamic application for O-rings.

Rotary Seals

Rotary seals are used for rotating shafts with the turning shaft protruding from the ID of the O-ring.

Oscillating Seals

The shaft of an oscillating O-ring application moves in an arc within the gland and is in contact with the ID of the seal. The shaft can twist so self-lubricated O-rings with a hardness of 80 to 90 durometers are most often used. If there is graphite containing compounds caution is necessary as they can pit stainless steel alloys.

Real Seal manufactures and distributes seal products and mechanical component goods. Established in 1970 as a distributor of O-rings, we are now a full-service supplier of sealing and mechanical components for many different industries.

One of the most technically advanced organizations in the industry, Real Seal maintains a fully equipped laboratory with a full-time chemist and technical staff. We are able to assist you with your design challenges and formulate materials that meet your specific needs for any types of seals. We can provide solutions to your problems and create an increased value for your company.

Top Applications for Industrial Seals

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We have been talking a lot about seals lately, but where are they actually used? Seals are used for many different things in various industries for various applications. Industrial seals are used to seal the opening found between a static and rotating component. It is very important to use high performance seals so that equipment works efficiently. Using proper seals will save companies money and energy cost.
Here are the top ten industries that use hydraulic, pneumatic seals, or a combination of the two.

1. Agricultural Machinery – Farm Equipment

It is vital for agricultural machinery to be functioning at the optimum level, especially during harvest season. These machines are out in the elements facing various weather conditions, UV exposure, and contamination from things around them. In order to repair and maintain farm equipment, one must use high performance seals in order to increase productivity and lower expenses. Harvesting, threshing, baling, drainage, and crop harvesting machinery use single acting hydraulic seals. The preferred materials are super polymers like Oz Red Super Polymer (ORSP), Oz Monyt and Wifflon. These products have superior lubrications properties and are extremely durable.

2. Amusement Machines

The Brooklyn economy is supported each year with a $58 million contribution from Coney Island in New York. On average, there are 15 million visitors annually. If any of the amusement rides break down that is a huge loss in income. Rides have to shut down for repairs if seals fail so it is important to use proper seals. Fair ground rides use low friction seals and wipers in rubber, polyurethane or TMCF seals and wipers in control valves.

3. Automobile Manufacturers

Vehicle assembly departments usually use pneumatic rams on assembly jigs. Pneumatics are quieter and cleaner so it prevents leakage from contamination the surroundings. Polyurethane and rubber which are sound absorbing materials are effective for achieving significant compressed air savings.

4. Cheese Manufacturers

Manufacturing and packaging machines in the cheese industry use pneumatic seals, spring energized seals, wipers and guide rings. High pressure nitrile rubber (HNBR), Teflon, or wifflon materials are recommended for these machines.

5. Coal Mining Equipment

Underground machinery makes extensive use of hydraulics while pneumatics are used for roof support machinery. The use of high performance parts contributes to safety in the mining industry. High performance parts are needed so that there is little downtime and minimal maintenance required. HNBR and Oz Monyt are often used as they are high pressure materials.

6. Concrete Pumping

Concrete is heavy, abrasive, viscous, and contains pieces of hard rock and will solidify if not kept moving. Because of this, there are many challenges to designing concrete pumps. Dangerous blockages can occur if the pump system is not set properly. Specialized sealing and proper guided element replacement is essential. There are special designs by Oz seals that are suitable for hydraulic rams that are used to operate concrete pumping plungers and hydraulic rams on the boom.

7. Diecasters

In order to die cast, you force molten metal under high pressure into a mold cavity. You can use a hot-chamber die casting or cold-chamber die casting. HNBR and viton materials are used as they can withstand extreme temperatures; they are used on tamping and furnace rams. Polymer compatibility should be checked for possible HFA/FHB fluid compatibility since hydraulic or mechanical pistons may come into contact with fireproof liquids.

8. Earth-Movers and Excavators

Heavy earthmoving, excavators, dozers, and backhoe loaders require high performance oils seals and hydraulic seal kids. The heaviest user of high performance seals and reliable Oz wipers are the mining and construction industries.

9. Printers

The fast-paced publishing industry needs machine parts that are manufactured with high performance polyurethanes and rubber materials. This allows for greater speeds and higher productivity. Pneumatics such as Teflon seals with spring energizers are used for printing presses and packaging machines.

10. Textile Manufacturers

Textile machinery uses things like shaft seals, spring energized Teflon seals and mechanical seals. A high performance polymer such as ORSP or Wifflon is ideal for compact spinning, high pressures and constant rotation of the air rams.
There are several other industries that use high performance seals for various applications. To find out what you require for your industry contact the professionals at Real Seal and they will be able to assess your needs.