seals product

Waveguide Seals

For effective EMI shielding and pressure sealing for choke, cover and contact flanges, Chomerics’ waveguide gaskets ensure low insertion, low flange leakage, maximum heat transfer and minimum outgassing. Made from CHO-SEAL 1239 and 1212 conductive elastomers, the gaskets are reusable and will not scar flanges.

Cover flange and flat contact flange gaskets are die-cut from CHO-SEAL 1239 sheet stock 0.027 in. (0.69 mm) thick, ±0.003 in. (0.08 mm). Containing an expanded metal reinforcement to eliminate cold flow, these gaskets can be supplied with a slightly raised lip around the iris opening for high-pressure, high-power applications.

RF/pressure seals for waveguide cover flanges are also available in Gask-O-Seal™ form. Gask-O-Seal waveguide gaskets consist of thin metal retainers which incorporate elastomer seals on each side, and raised knurls which bite into flange surfaces to provide good electrical contact. For more information on Gask-O-Seal products, contact Parker Hannifin, Cleveland, OH, 1-800-272-7537 and ask for Gask-O-Seal catalog #OSD-6411.

Choke flange and grooved contact flange gaskets are molded from CHO-SEAL 1212 material, and are available with O- or D-cross sections.

Properties of CHO-SEAL 1212 and 1239 materials are shown in the table below.
Specifications CHO-SEAL 1212 CHO-SEAL 1239
Type (Ref: MIL-G-83528) K G
Volume Resistivity (ohm-cm, max) as supplied (w/o PSA) 0.005 0.007
Hardness (Shore A ±5) 80 80 ±7
Specific Gravity (±0.25) 3.5 4.75 ±0.75
Tensile Strength psi (MPa), min. 400 (2.76) 600 (4.14)
Elongation (percent, min/max) 100 / 300 20 / NA
Tear Strength (lb/in, min) 40 70
Compression Set, 70 hrs. @ 100°C (percent, max 35 Not Applicable
Low Temperature Flex, TR10 (°C, minimum) –45 Not Applicable
Continuous Use Temperature Range (°C) –55 to 125 –55 to 125
Shielding Effectiveness (dB, min.)
200 kHz (H Field)
100 MHz (E Field)
500MHz (E Field)
2 GHz (Plane Wave)
10 GHz (Plane Wave)
70
120
120
120
120
70
110
110
110
110
Electrical Stability (ohm-cm, max.) Heat Aging 0.010 0.010
Vibration During
Resistance After
0.010
0.005
0.010
0.007
Post Tensile Set Volume Resistivity 0.010 NA
EMP Survivability (kA per in. perimeter) >0.9 >0.9