Mechanical seal with embedded lubrication

Mechanical seal with embedded lubrication

Mechanical seal for providing a seal around the drive shaft of a variable displacement swash plate type compressor used in an air conditioning system for a vehicle comprising a rotating bearing surface, an associated stationary bearing surface and a lubricant embedded in the stationary bearing surface.

During operation of the compressor, the rotating bearing surface is caused to move against the stationary bearing surface causing lubricant to be released between the bearing surfaces, thereby providing efficient lubrication of the bearing surfaces.

The present invention relates to a mechanical seal, and more particularly to a mechanical seal disposed between two relatively moving bearing surfaces such as, for example, between a rotating bearing surface and an associated stationary bearing surface for providing a seal around the drive shaft of a variable displacement swash plate type compressor used in an air conditioning system for a vehicle.

A mechanical face seal is frequently used in an automotive cooling pump or refrigeration compressor. Generally, such seals include a stationary annular bearing surface integral with the compressor housing and an associated sealing ring disposed on a rotating drive shaft. A means are provided for urging the facing surfaces of the stationary bearing surface and the sealing ring together. The rotating surface of the sealing ring contacts the stationary bearing surface to form a sealing face which is perpendicular to the shaft. The stationary sealing surface is typically formed of cast iron, stainless steel, ceramic, hard chromium-plated steel or hardened bearing steel; and the associated rotating ring is formed of sintered carbon-graphite, resin-bonded carbon-graphite, resin impregnated carbon-graphite or ceramic.

Refrigeration compressors are used to compress refrigerants, such as carbon dioxide, as part of a standard vapor-compression refrigeration cycle. Typically, a gaseous refrigerant is mixed with a liquid lubricating medium, such as oil, before entering the compressor. The oil is employed to lubricate the compressor components, such as bearings and seals, to reduce component wear. Refrigeration compressors typically include a shaft rotatably supported by bearings within a compressor housing. Mechanical seals are typically employed in such refrigeration compressors to inhibit leakage of lubricating oil between the compressor housing and the shaft.

When a mechanical seal is mounted in a conventional variable displacement swash plate type compressor of an air-conditioner for a vehicle in which carbon dioxide refrigerant is used, the operational conditions of the mechanical seal become severe. The pressure within such a compressor is greater than within a compressor using a different refrigerant, resulting in a greater axial sealing force on the mechanical seal. Additionally, conventional lubricating oil is not soluble in carbon dioxide and therefore the lubricating oil cannot be efficiently distributed within the compressor. Such inefficient distribution of lubricating oil can cause the sealing face of the mechanical seal to receive an insufficient amount of lubricating oil. Insufficient lubrication will cause excessive friction in the sealing face, resulting in over-heating and failure of the mechanical seal.

The mechanical seals of the prior art rely primarily on the flow of oil mixed with refrigerant gas to effect proper lubrication. Therefore, ineffective lubrication of the sealing face occurs due the lack of consistent flow of refrigerant gas within the compressor.

It would be desirable to produce a mechanical seal wherein a constant supply of lubrication is released into the sealing face to result in improved lubrication of the mechanical seal.

Consistent and consonant with the present invention, a mechanical seal wherein a constant supply of lubrication is released into the sealing face to result in improved lubrication of the mechanical seal has surprisingly been discovered.

How dry gas seal works in a Cenrifugal compressor?

Question by Ravi: How dry gas seal works in a Cenrifugal compressor?
Mechanical seal and dry gas seal working principle

Best answer:

Answer by pboltonchina
Try this site http://www.howstuffworks.com it may help

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whatis a mechanical seal?

Question by sandeep d: whatis a mechanical seal ?
used in centrifugal pumps.

Best answer:

Answer by dawnsdad
It is a seal that separates the motor housing from the wet end of the pump. It is installed behind the impeller. Since the impeller must be surrounded by water and is also connected to the motor (which cannot be wet), a mechanical seal is used to prevent water from leaking from the pump volute (were the impeller is located), down the motor shaft. It allows the motor shaft to rotate without leaking.

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what is quench in mechanical seal?

Question by masoud: what is quench in mechanical seal?

Best answer:

Answer by Bert K
A seal Quench is a product supplied to the atmospheric side of a mechanical seal (such as cool water). A water quench can help reduce the amount of heat transmitted from a hot product being pumped to the pumps bearing frame. A steam or water quench can be used to keep product from oxidizing or reacting with oxygen on the atmospheric side of the seal faces by replacing the atmosphere with steam or water. The oxidized product can hang the seal up ( keep it from adjusting to shaft movement) causing a leak. Those are some of the most common uses of a seal quench. But there are many other uses for quenches such as a steam quench to keep the seal faces warm on temperature sensitive applications like pumping asphalt. It would keep the faces from being glued together by the asphalt when the pump is shut down.

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mechanical seal for pump?

Question by edwin p: mechanical seal for pump?
Why do some pumps need seal pot and nitrogen gas as blanketing

Best answer:

Answer by Robert A
Pump handling volatile liquid may need seal pot and nitrogen blanketing to prevent fire/explosion.

Edited Comment: Despite comments below on negligible leakage from mechanical seals they can and do fail and for safety reasons provision has to be made for this when leakage would lead to a hazard. In my experience steam is more commonly used than nitrogen. However steam may not be available.

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