Pressure Fittings Flashcards
What is the purpose of pressure fittings?
-Seal between tubing/piping, components, or vessels
-Allow for removal and installation of components
-Reliably seal system pressure
Why preload pressure fittings?
-The stress amplitude of the bolts and other parts is greatly reduced, resulting in improved fatigue life.
-Separation of the sealing surfaces (“gapping”) is minimized resulting in more consistent sealing.
What are some methods to control preload?
Torque measurement
Bolt elongation measurement
Instrumented bolts
Indicating washers
What is a vacuum coupling used for?
Vacuum and low pressure systems. Where softgood off gassing is a concern
What is a tapered pipe used for?
Water, steam, natural gas, & general use.
designed for sealing without the necessity of sealing compounds
What are Pipe Flanges used for?
Water, steam, natural gas, and general use in many applications for connection between pipes
What are Grayloc Connectors?
similar to pipe flanges except that sealing is accomplished by a tapered seal ring that fits between and inside a conical section of the connectors. A clamp creates preload from the outside by acting on fitting external tapered sections
What does AN stand for?
Air Force- Navy Aeronautical Standard
(True or False) SAE J514 fittings can be substituted for AN/SAE aerospace fittings where AN/SAE aerospace fittings are required.
False. Even if J514 and AN/SAE AS fittings screw together by hand, the root radius to minor diameter interference may be an issue when the fittings are tightened
What is a 37 Flared Tube Connection?
A flared tube end to hold & seal the medium under pressure. Main construction consists of three pieces: the body, sleeve & nut. The end of the tube is flared to 74 degrees included angle and held in between the body nose and the sleeve with a nut on top of them, thus resulting in a very effective seal between the fittings and the flared tube.
What is a Boss Gasketed Fitting “AN Boss”?
-Media exposed threads may result in thread lubricant migrating to the media, especially if the lubricant is soluble in the media.
-Krytox 240AC is quite soluble in MMH and it is somewhat soluble in other hydrazines and NTO. It is no longer allowed in hydrazine systems.
-Threads also create an entrapment area that is a concern for Hydrogen Peroxide.
-Cold temperatures may result in leakage due to gasket shrinkage, especially for Teflon
What are Gamah Metal Seal Fittings?
- Metal to metal sealing
- Designed to be a redundant seal fitting with one seal between two flat faces and the second seal being a seal that deflects (similar to a spring washer) and mates between two sealing surfaces.
What is a Ferrule Tube Fitting? (Swagelok)
A 2-piece conical ferrule is initially swaged (deformed) into the outside diameter of the tubing. The conical outside of the ferrule seals against a mating conical surface in the fitting body
