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31 Cards in this Set
- Front
- Back
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Flourocarbon rubber (such as Viton) is incompatable with... |
HFC refrigerants and is unauthorized |
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A Dynamic Seal is....
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a sealing device used between parts that have relative motion (piston,shaft seals)
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A Static Seal is...
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a seal where there is no relative motion between the seal and any parts in contact with the seal
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Nitrile (or Buna N) Rubber....
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most resistance to petroleum products
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Butyl rubber...
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-low permeability rate for gases
-ideal rubber for sealing gases |
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The most commonly used elastomers have a hardness between....
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65 and 75
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Explosive decompression is when...
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gasses trapped in a seal expands after rapid decreas in system pressure causing blisters in seal
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Best elastomers for high temperatures are...
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silicones, flourosilicones, and flourocarbons
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Keep preformed packings in.....
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their original envelopes
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Arrange preformed packings so...
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older seals are used first
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Storing temperatures for packings?
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60°F-100°F and should not exceed 125°F
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O-Ring seals are considered____type shelf life items
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type I
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If V-Ring packing age exceeds 10 years...
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packing should be discarded
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Shelf life of Nitril or Buna N
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15 years
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Shelf life of Ethylene-Propylene and Flourocarbon rubber
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unlimited
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Normally, backup rings are required for operating pressures over...
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1500 lb/in
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Best overall packing used for static applications
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O-Ring
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Gland face angle must not exceed...
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5 degree maximum
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Clean thread tube fitting seal using local procedures such as....
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caustic dip or wiping with clean lint free cloth
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Do not use skydrol based greases with...
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flourocarbon rubber
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The stretching of the O-ring during assembly usually should be limited to....
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twice the rings actual size
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When o-ring is installed in final position, the diameter shall have a permanent stretch of no more than...
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5 percent
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Avoid______ when maneuvering the o-ring into place.
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rolling or twisting
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Splicing of o-rings are....
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not usually recommended
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When glueing both ends of a spliced o-ring, hold in contact with firm pressure on the bond for....
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10 to 30 seconds
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When glueing o-ring splices together, allow adhesive to cure for....
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30 seconds
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Allow o-ring adhesive to cure at least____before flexing or scratching
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1 hour
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Anti-extrusion rings are also known as...
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back-up rings
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The most commonly used backup rings are....
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tetraflouroethylene (TFE of Teflon) type
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Tetraflouroethylene (TFE) characteristics
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-impervious to oils and solvants
-resistance to salts and acids |
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When split ring packing is used, joints shall be staggered....
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90°
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