PTFE Encapsulated O-Rings

Encapsulated o-rings are o-rings consisting of a seamless and uniform Teflon encapsulation which completely encloses a rubber core material. Elastomer/rubber core material are a choice of Silicone or Viton. The combination of  these components creates an o-ring that is virtually chemically inert and compression set resistant for use in harsh sealing environments. This combination of chemically resistant polymer jacket over a low-compression set elastomer provides unique properties for a range of demanding applications

PTFE Encapsulated o-rings are o-rings consisting of a seamless and uniform PTFE FEP/PFA encapsulation/jacket which completely encloses a core material Viton® fluoroelastomer (also available in silicone). The combination of these components creates an o-ring that is virtually chemically inert and compression set resistant for use in harsh sealing environments. Encapsulated o-rings will decrease downtime and hence increase profitability wherever corrosive fluids and gases cause premature seal failure.

The PTFE provides a non stick surface for easy cleanup of viscous materials. These o-rings have a low coefficient of friction of .2 on metal and the o-rings surface is self lubricating. The PTFE encapsulation makes the o-rings sanitary by eliminating contamination of fluids by the elastomers. The o-rings are sterilizable and autoclavable, FDA compliant, USP Class VI compliant, NSF compliance available for specific applications.

Encapsulated o-rings are specifically designed to address the problem of sealing the most hostile chemicals and extreme temperature applications. Encapsulated o-rings consist of a solid or hollow elastomeric core encapsulated in a PTFE FEP or PFA sheath. The elastomeric core may be fluorocarbon or silicon rubber. Solid core encapsulated o-rings are generally used in static applications. Hollow Silicone core encapsulated o-rings are commonly used in applications where lower sealing force is required as in semi dynamic applications. The encapsulated o-ring offers an effective solution for many difficult applications. The PTFE FEP or PFA encapsulation actually affects the seal and the elastomeric core insures consistent compression on the seal. The result is an overall sealing compression, increasing with medium pressure. The encapsulated o-ring behaves like a highly viscous fluid, any pressure exerted on the seal is transmitted in all directions. Maximum operating temperature for FEP is 205°C (400°F) and for PFA 260°C (500°F).

Benefits

* Excellent chemical resistance
* Temperature range
  - silicone core: -75°F to 400°F (-60°C to 205°C)
  - flurocarbon core: 5°F to 440°F (-15°C to 205°C)
  - special applications are possible up to 500°F (260°C)
* Overall hardness 85° Shore A ± 5 durometer
* Sterilizable.
* Pressures from vacuum to 10000 psi (700 bar, 70 MPa)
* Low compression set characteristics.
* Anti-adhesive properties, non stick surface, low coefficient of friction
* FDA compliant
* No restrictions on inside diameter

PTFE Seals & Rings

PTFE Seal Material Offers Greater Durability, Longer Operating Life & Other Mission-Critical Benefits.

Polytetrafluoroethylene (PTFE) seals and piston rings have started to replace their carbon counterpart as PTFE seals and rings offer greater durability, have a longer operating life, and can be operated at various pressures, velocities and temperatures.

PTFE seals and rings are becoming more common in a variety of applications and industries because of the unique advantages they offer.

Advantages

PTFE seals and rings have various properties that make it ideal for a wide range of applications. Some advantages of PTFE seals and rings include:

Low-Friction
High Wear Resistance
Chemical Resistance
Ease of Machinability
Broad Temperature Tolerance (-328F to +500F)
Anti-Adhesive Properties
Low Stick Slip

Applications

PTFE seals and rings are ideal for a variety of applications, particularly in fluid & gas applications.

Other applications where PTFE seals and rings are common include:

Gas Compressors (Air, Oxygen, Hydrogen, Carbon Dioxide, Ammoniac, etc.)
Hydraulic & Pneumatic Cylinders
Metallic & Thermoplastic Cylinders
Dosage Pumps
Liquid Pumps with High Fluidity
Liquid Oxygen Pumps
Liquidated Gas Compressors (butane, propane, etc.)
Liquid and Gas Vacuum Pumps
Reciprocating Compressors
Rocking Piston Pumps
Braking Systems
Combination Heat & Power Systems

Source:https://www.sukoptfe.com/ptfe-seals-rings

PTFE Piston Ring Types

Traight Joint;Scarf Joint;Overlapped Joint;Gas-tight Joint

Traight Joint
Piston rings with straight joints are used for sealing pressure differences above 15 bar.

With this gap, the leakage is slightly higher than with piston rings that have a scarf joint. Because of the high compressor speeds (rpm) typically achieved today, the loss of gas from leakage has only a minor impact on compressor performance.

The amount of gas leakage is negligible.

Scarf Joint
Piston rings with scarf joints are used for sealing pressure differences above 15 bar. During the run-in period, the sealing effect of scarf joints is slightly better than that of piston rings with a straight joint.

Overlapped Joint
The overlapped joint achieves a favorable sealing effect.

For this reason, it is primarily used for sealing gases with a specific light weight. Because of bending stress and the resulting  risk of breakage in the overlapping areas, piston sealing rings with overlapped joints should only be used in compressors operating with pressure differences of max. 15  bar.

Gas-tight Joint
Our gas-tight piston rings achieve the best sealing effect.

The special design of the joint reduces leakage to a minimum. The differential pressure is limited to a maximum of 15 bar. During assembly, please note that the piston ring achieves a good sealing effect in one direction of pressure only.

Source:https://www.sukoptfe.com/ptfe-piston-ring-types

PTFE Piston Rings

Polytetrafluoroethylene (PTFE) seals and piston rings have started to replace their carbon counterpart as PTFE seals and rings offer greater durability, have a longer operating life, and can be operated at various pressures, velocities and temperatures.

PTFE seals and rings are becoming more common in a variety of applications and industries because of the unique advantages they offer.

PTFE Piston Rings and Guide Rings (Rider rings) for dry-running applications are currently a focal point of technical development. 

They significantly reduce a machine’s operating costs and, in today’s increasingly environmentally aware society, make it easier for operators to fulfill stricter environmental legislation.

Properties

Exceptionally low friction coefficient in combination with metals and plastics
Antiadhesive behavior without any stick-slip effect
High elongation properties enabling easy fitting
of sealing and guide rings to one-piece pistons
Exceptionally large temperature range from –200°C to +260°C
Chemically resistant to almost all solid, liquid, and gaseous media
Ageing-resistant
Nonflammable
Physiologically neutral in the stated temperature range

Suitable for the Following Application Areas

Compressors operating under full- and low-lube conditions
Gas rotary pumps
Expansion machinery
Liquid gas and vacuum pumps
Rocking piston pumps
Rotary compressors for loading/unloading of silos
Generation of oil-free compressed air for the
food processing industry, pharmaceutical industry, and dentistry
Compressed air for the craft and do-it-yourself market
Pneumatic hammer drills
Automotive technology, including ride leveling
and air-conditioning systems

Source:https://www.sukoptfe.com/ptfe-piston-rings

PTFE Piston Seals and Rod Seals

The rod seal is the most critical seal on any type of fluid power equipment preventing leakage of fluid from within the cylinder to the outside. Leakage through the rod seal can reduce equipment performance, and also in extreme cases can cause environmental issues.

PTFE piston seals (PTFE rod seals) as Spring-energized seals and memory packings are always the ideal choice for sealing static or dynamic pistons and rods.

Properties

Outstanding dry-running characteristics
Low wear
Low friction
Variable friction conditions through choice of spring characteristics
Extremely low breakaway forces even after prolonged downtimes
No stick-slip effect even at low sliding speeds
High dimensional stability
High chemical and thermal stability
No volumetric change by swelling or shrinkage
Compact seal, suitable for O-ring assembly spaces in acc.
Good cost-benefit ratio
Dimensions from Ø 2 to 3,000 mm available
Very good wiping effect with abrasive media, such as paints and lacquers
Sterilizable
Easy to rinse

Suitable for the Following Application Areas

Automotive industry, e.g., in gasoline direct injection and in headlight cleaning devices;
General mechanical engineering, e.g., in valves, solenoid valves, CNC machines, compressors, and vacuum pumps as well as tank systems;
Aerospace industry, e.g., in landing gear systems;
Food processing industry, e.g., in filling machines and metering systems;
Pneumatics, e.g., in cylinders and other pneumatic components;
Medical engineering and analytics, e.g., in chromatography and endoscopy;
Offshore technology, e.g., as petroleum and natural gas seals;
Chemical plant and equipment technology, e.g., in apparatus and container engineering;

Source:https://www.sukoptfe.com/ptfe-piston-seals-and-rod-seals

PTFE O-Ring

Polytetrafluoroethylene (PTFE) is a high molecular weight polymer, one of the most versatile plastic materials known and useful for a large range of
products for applications excluded to other materials.

Polytetrafluoroethylene (PTFE for short) is a low friction synthetic rubber that has long been used for sealant applications for a variety of substances including gasses, fluids, and chemicals.

PTFE O-Ring Temperature Range

Although PTFE has lower mechanical properties compared to other plastics, the material’s chemical resistance in tandem with its ability to withstand a wide temperature range (-100oF to +400oF) allow PTFE o-rings to provide effective resistance to weathering as well as electrical and thermal insulation.

Because PTFE is such a dense material, it cannot be “melt processed” – it must be compressed and sintered to form useful shapes (like o-rings).

Top Applications

outdoors
lubricants
hydrocarbons
acids
alkalis
detergents
alcohol
ketones
steam
refrigerants

Mechanical Weaknesses

high vacuum seals
low compression vacuum sealing flanges
super-heated steam

Increase Mechanical Properties with Filled Grades
As shown in the table above, PTFE o-rings have some mechanical vulnerabilities compared to other plastics. If needed, these properties can be enhanced by adding fillers, such as:

Glass Fibers
Carbon
Graphite
Molybdenum disulphide
Bronze

Source:https://www.sukoptfe.com/PTFE-O-Ring

1/2X260" PTFE Seal Tape

1/2X260" PTFE Seal Tape, Pack of 25 1/2" x 260", Virgin White PTFE Thread Seal Tape, 0.4 Density, 0.003" Thickness, Temperature Range -400 Degrees Fahrenheit To 500 Degrees Fahrenheit.

Color: Multicolor
Assembled Product Dimensions (L x W x H): 2.00 x 2.00 x 1.20 Inches

55mm x 39.5mm x 6.3mm O Ring PTFE Seal

PTFE Ring Outside Diameter : 55mm / 2.16";
Ring Inner Diameter : 39.5mm / 1.55"
PTFE Ring Height : 6.3mm / 0.248";
Color : Black & Brown
Net Weight : 14g
Package Content : 1 x Piston Ring Seal

The PTFE Seal ring for pistons. Composed of a PTFE wear-resistant ring and an O-ring. With its elasticity, the O-ring can offer compensation for the wear of the PTFE ring. Applied to the sealing of hydraulic cylinder piston.