All of the following application information should be used in conjunction with the pressure/temperature rating graph and
corrosion chart.
(B) Buna N – (Also known a Nit rile) is rated to 300 psi from -20° F. to 180° F. It is excellent for use on petroleum
products. The Material is IPC No. W-29-1, Black in color, and may have one red dot.
(N) Neoprene seats are also rated to 300 psi from -20° F. to 180°F. Neoprene is excellent for use with refrigerants
such as Freon and for use on Oxygen or Nitrous Oxide. Seats are color coded with one yellow mark.
(T) TFE seats, made from virgin TFE material, are suitable for -50° F. to 450° F. at pressures to 1000 psi. TFE is the
most common sealing material and is excellent for most media. TFE has excellent chemical resistance and is white
in color.
(R) Reinforced TFE seats are suitable for temperatures from -50° F. to 450° F. at pressures to 1500 psi. Reinforced
TFE seats are made with glass filled TFE. They are harder than virgin TFE (except for hot strong caustics). These
seats can be identified a white with green or blue speckles. They also have seven relief slots instead of six if they
are white.
(MT) Multifill seats. A TFE seat (filled with carbon, glass and graphite) that is good for temperatures ranging
from -450° F. to 650° F. at pressures to 1500 psi. It is an excellent seat material for steam and thermal fluid
(hot oil) services, and is good material for difficult applications. It also has better cycle life than other materials.
These seats are black in color.
(D) Lubetal, (Delrin AF), is a high pressure seat material. These seats are rated at various pressures (up to 5000 psi),
depending on valve size and style. The temperature range is -70° F. to 180° F. This material should not be used on
oxygen service. They are made from Dupont Acetyl homopolimer and are filled with Teflon and glass fibers. Lubetal seats
are green in color.
(U) UHMWPE, Ultra High Molecular Weight Polyethylene, is rated to 1500 psi at temperatures from 0° F. to 200° F.
Material is Hercules UMW 1900 or equal. This can be in low to medium level radiation service and in applications
where fluorocarbons can not be tolerated. Abrasion resistance is quite good. UHMWPE seats are white in color (more
translucent than TFE). ¼” thru ¾” UHMWPE seats may be injection molded. These seats appear very similar to TFE.
(PK) High-per fill is rated to 500 psi, and to temperatures from -70° F. to 600° F. High-per Fill has very good
pressure capability at elevated temperatures. It is PEEK (Poly Ether Ether Keton) filled with glass and graphite to give
excellent abrasion resistance, and is resistant to most medias except sulfuric and other strong oxidizing acids and
halons. It is black in color and feels (and sounds when tapped) much harder than Multifill. When supplied as parts, a
white streak shows on the top surface.
(SS) Alpha, suitable for -20° F. to 600° F. at 1000 psi. 316L metal matrix filled with TFE, this material combines
the strength and abrasion resistance of metal with the lubricity of TFE. The seat is gray in color, has a seal groove
in the back face, and is noticeably heavier than plastic seats. Alpha seats DO NOT have relief slots.
(G) Gamma- The benefits and features of Alpha seats with increased temperature capability (1000° F.) by substituting
graphite for TFE as the lubricant. Gamma is successful on hot abrasive services. This seat material has all the
advantages of Graphite without the brittleness which causes Graphite seats to fracture and fail.