Pressure Balanced Piston Rings
PRESSURE BALANCED PISTON RINGS
Pressure balancing maximizes ring life by minimizing the force on the sealing surface. The ring wear is reduced and the forces acting on the seal are stabilized. AAVOLYN Type 480 shown below provides excellent performance in discharge pressures over 250PSI.PISTON RING FUNCTION
PISTON RING DESIGN
- Creates seal in two directions
- Prevents gas or liquid being sealed from traveling past in cylinder
- Compressed gas presses against face of ring forcing it back against side wall of the piston groove, creating a seal between the side wall of the ring and piston groove. Compressed gas travels under piston ring and forces it out against cylinder wall
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- Ring conforms to the diameter of the cylinder and allows clearance under and alongside of the ring to allow it to move freely in the groove in which it is contained
- Side clearance based on ring material and temperature at operating conditions
- Space under ring provides room for the sealed substance to provide pressure against the ID of ring creating a seal on OD of the cylinder
Aavolyn Packing Kits
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OIL RINGSTYPE 320
The AAVOLYN type 320 radial oil scraper ring is designed to be used pinned in sets as a wiper assembly. The 320 design is installed with the wiping edge toward the oil source to provide maximum oil removal.
The 320 design includes the unique tapered wiping edge. Deep oil groove in the bore and large oil ports to allow rapid removal of oil wiped from the rod. It is used in many natural gas compressors depending on the design of the compressor manufacturer.back to top
Aavolyn Oil Rings Type 320
Aavolyn TY260/230 PBU Design Packing
AAVOLYN PRESSURE BALANCED UNIT (PBU) DESIGN PACKING
The pressure balanced packing ring (AAVOLYN TYPE260 PBU) maximizes the benefit of pressure balancing in a packing ring seal. The ring is designed to allow just enough resultant force on the piston rod to seal the gases without developing additional forces to cause ring wear.
You can expect normally two to three times the life of the PBU over other ring designs.back to top
Aavolyn TY260 PBU Design Packing
Heat Sources Play Havoc on Ring Wear
HEAT SOURCES PLAY HAVOC ON RING WEAR
Over lubrication is undesirable - when oil fills the packing groove and does not let the ring float and seat itself heat will be generated and rings lost.
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- Operating Temperature
- Operating Pressure
- RMS Finish Of Sealing Surface
- Physical Properties Of Sealing Material
- Lubrication (Lube, Mini-Lube Or Non-Lube)
- Properties Of Gas Or Liquid To Be Sealed
- Stroke And RPM
- Compression Ratio
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Aavolyn TY655 Fab Cup Liquid Cooled Design
AAVOLYN TY655 FAB CUP LIQUID COOLED DESIGN
AAVOLYN engineers developed the fabricated cup configuration as the most efficient type of internal coolant design. The Type 655 consists of a fabricated coolant cup composed of a cup and a bushing pressed together to form a sealed internal coolant area. This coolant area has permanent O rings on either side to prevent leakage between the pressed joints. The AAVOLYN design brings the cool-ant areas close to the bore of the case to allow maximum heat transfer. The size of the coolant areas are enlarged to provide a large surface for heat transfer. This design is used in all gas services and all discharge pressures.
One of the value added features of the Type 655 is that the O ring sealing the coolant flow from cup to cup does not go around the rod. Hence, the rod does not have to be removed to replace them resulting in a major time saver.back to top
Aavolyn Corp Booth
Piston Rider Ring Conversions
PISTON RIDER RING CONVERSIONS
Teflon ®Rider rings or Wear rings were developed originally for non-lubricated gas service to prevent the metal piston from contacting the cylinder wall without a lubrication film on the wall itself. Todays cylinder designs incorporate rider rings in both lube and non-lube service. This configuration allows for better alignment and also provides the added safety if lubrication is interrupted. To provide sufficient wear life for the rider ring, the piston has to be configured to add the rider ring groove and additional space between the piston O.D. and the cylinder.back to top
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RIDER RING WIDTH FACTORS
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- Weight the piston supports which is the piston and one half of the piston rod.
- The wear properties of the filled Teflon ® being used
- Operating temperature and pressure
- Wear space between the cylinder and the piston.
Rider Ring Width Factors
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RIDER RING ADDITIONAL FEATURES
Solid rider rings are installed when the rider groove travels more than halfway into the counterbore or valve port. This de-sign of ring is stretched over the piston and comes back onto the rider ring groove. The SOLID design prevents the ring from opening up and catching on the piston grooves.
Face and side grooves are added to the rider ring to allow the gas being compressed to bypass the rider without letting the rider ring act as a seal. The large surface area of this ring will develop significant frictional heat if the ring is sealing. The grooves allow the gas to travel past the ring easily.
When designing the piston or modifying it to add rider rings or reconfigure to improve ring life, it is important that the customer draw on as much experience as possible. AAVOLYN has many successful installations in the field where original OEM specs have been improved to provide longer ring life, higher performance with reduced downtime.back to top
Aavolyn Corp Tradeshow
Aavolyn DuPont 2009 Certificate of License
AAVOLYN Corp is again proud to be a recipient of the 2009 Certificate of License issued by Du Pont Fluroproducts. William VanHoeven of Du Pont is shown presenting Lynn Farrell, President of AAVOLYN with the certificate of license at AAVOLYNs offices in Millville, New Jersey.
Aavolyn DuPont Fluroproducts
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DU PONT TEFLON® PTFE FLUOROPOLYMER RESIN
Aavolyn relies on DuPont resin to produce a wide variety of lubricant-free seals for reciprocating compressors used by the natural gas industry.
Less wear, longer part life - because Teflon® PTFE has one of the lowest coefficients of friction of any solid material, it is ideal for lubricant-free compressor seals. Parts are designed to function in either a lubricated or non-lubricated environment, but in either case minimize friction operating heat and wear at the ring-cylinder interface.
Lower heat generation also helps reduce wear on the piston and piston rod. Teflon® PTFE can withstand continuous service temperatures up to 260 C. ( 500 degrees F). Consequently, Aavolyns sealing rings made with the polymer permit high compressor operating temperatures while minimizing wear on seal surfaces.
Impervious to most gases, Aavolyns seals stands up to nearly all process gases, including oxygen, hydrogen, nitrogen, argon, ammonia, methane, and carbon dioxide.
Aavolyns seals based on TEFLON® PTFE are substantially less expensive than those made with exotic alternative materials.
Low friction, high temperature capabilities and resistance to chemical attack by process gases makes Aavolyn packing rings along with its piston and rider rings an ideal material for high performance compressors.back to top
Du Pont Teflon® Ptfe Fluoropolymer Resin