High-performance Metal Spring Energized PTFE Seals

DEF has been available with various PEEK seals since before 2015. The most famous of these is a Spring seal made of PEEK. But do you really know anything about PEEK? 

Today let’s take a look at this mysterious material

PEEK (Polyether ether ketone) is one of the slowest developing and expensive special engineering plastics. It was first developed and commercialized by ICI in 1981. PEEK is a semi-crystalline polymer with excellent comprehensive performance, which can be used as a substitute for metal materials in most occasions, mainly used in aerospace, military equipment, nuclear power, medical equipment, electronic semiconductor and other fields.

The price of PEEK is expensive. Generally, domestic PEEK costs dozens of dollars per kilogram, while imported PEEK costs more than 200 dollars per kilogram. PEEK’s high cost is inseparable from its outstanding performance. Compared with other resin materials, PEEK has excellent performance in high-temperature resistance, mechanical property, stability, corrosion resistance, aging resistance, processing performance and other aspects.

Product Description
The Spring Energized PTFE Seal is a spring- energized, pressure-assisted sealing device consisting of a PTFE (or other polymer) seal partially encapsulating a corrosion-resistant metal spring energizer.
The PTFE jackets are precisely machined, filled with PTFE composites and other high performance polymers, function at temperatures ranging from cryogenic to 250 C and inert to almost all chemicals. Some types also can be used in sanitary environment.

PTFE filled with bronze(glass, graphite, carbon, etc.)

Application Example
Radial Seals in Static Service.
Radial Seals in Reciprocating Motion.
Radial Seals in Rotary Motion.
Inside face Seals in Static and rotary Service.
Outside face Seals in Static and rotary Service.

Section structure
Symmetric, for Rod, for Piston are available.

Spring type:
U shaped spring(Type 400)
Round wire spring (Type APS)
O shaped spring (Type 103)

Standard Heel Groove.
Extended Heel Groove
Flanged Heel Groove.

Both imperial and metric sizes are available on all types.

Its main properties are as follows:

1.High temperature resistant
PEEK is one of the most heat-resistant thermoplastic materials available, with a melting point of 343 ° C and a U.S. UL certified long-term service temperature of 260 ° C. PEEK maintains excellent mechanical properties even at temperatures as high as 300 ° C. PEEK thermal deformation temperature is 135~160℃, 20% glass fiber reinforced PEEK thermal deformation temperature is 286℃, 30% glass fiber reinforced temperature is 300℃.
2.Heat aging resistant
PEEK has outstanding thermal aging properties. Even after thermal aging at 200℃ for 10000h, PEEK tensile strength, mass and appearance will not change significantly.
3.PEEK has outstanding thermal aging properties
PEEK has excellent mechanical properties and is the perfect combination of toughness and rigidity among all resins. PEEK has high rigidity, and its strength and fatigue resistance are comparable to some metals and alloy materials. PEEK can maintain high strength even at high temperature, bending strength up to 24MPa at 200℃, bending strength up to 12~ 13mpa at 250℃, and compression strength up to 12~ 13mpa, especially suitable for manufacturing components that work continuously at high temperature.
4.Good wear resistance and self-lubrication
PEEK resin itself has excellent self-lubrication and wear resistance. After filling, the friction coefficient of the resin can be reduced to 0.15, and the abrasion loss is extremely low. It can achieve oil-free lubrication and be used in many harsh environments such as high temperature, high load and high speed. PEEK polymer and its composites have excellent wear resistance, making them excellent bearing materials.
5.Chemical resistant
PEEK is resistant to almost any chemical except for strong oxidizing acids, such as concentrated sulfuric acid, and it remains chemically stable even at higher temperatures.
6.Resistance to hydrolysis
PEEK has good hydrolysis resistance, and its saturated water absorption rate is only 0.5% at 23℃. PEEK has the best heat resistant water and steam resistance of all engineered plastics, and can be used for long periods at 200 ° C steam or for short periods at 300 ° C high pressure steam.
7.Electrical insulation property
PEEK resin is an ideal electrical insulator, which can maintain good electrical insulation performance under severe working conditions such as high temperature, high pressure and high humidity. Usually the volume resistivity can be up to 10 of 15 to 16 power Ω cm, dielectric constant of 3.2 ~ 3.3 F/m, under the condition of 1 KHZ dielectric loss 0.0016, 17 KV breakdown voltage, arc resistance 175 v.
8.Good machining performance
PEEK has high thermal decomposition temperature and good fluidity at high temperature, so it has good processing performance. It can be processed in various ways: injection molding, extrusion molding, molding, blow molding, melt spinning, rotation molding, powder spraying, etc.
9.Radiation resistant
PEEK has a strong resistance to gamma irradiation, surpassing the most irradiation-resistant polystyrene general-purpose resins, such as high-performance wires made from PEEK resin, which maintain good insulation at gamma irradiation doses up to 1100Mrad.
10.Flame retardant and low smoke
PEEK flame retardant is good, has self-extinguishing, in the case of not using any additives, 1.45 mm thick PEEK sample flammability grade is UL94V-0; 3.2 mm thick PEEK sample has a flammability grade of UL94 5-V. Even when burning, the amount of smoke and the amount of toxic gas produced is very small, far less than other types of resin.

Post time: Dec-05-2020