Sealant/Grease Injection Fittings

[Angsi2]

For which sizes and conditions are the above fittings necessary? I have given some examples here and if it is otherwise, let me know:

1. All trunnion mounted valves i.e. maybe 4" to 6" and larger for ANSI classes
2. Expensive valves in extreme high pressure and critical isolatio service i.e. 15,000 psi API 6A design 2" and above

In addition to sealing functions, these fittings can also be used for lubrication. Regardless of what the valve manufacturers might say, I understand it will be a good practise to flush the valves periodically to rid of debris/particles etc, especially in a dry gas service.

Comments welcome.

 

[gerhardl]

I have no direct experience either in the service nor the specifications or practical use of greasing and sealing injection. Please look as my remarks as additional trying to start the discussion:

1. Suggestion for reformulation: Is there any ongoing trend for more use of or away from sealant and grease injection fittings?

In my opinion:

a. On greasing. With modern material choices, valves should in general not be greased. Reason: correct materials and constructions make this unnecessary, you puncture the valve and make it possible to get unwanted material in, and emissions out. (Is greasing necessary for some special services?)

b. On sealant injection: only necessary if sealing or valve itself cannot be changed, and only as preliminary repair. Should be avoided for reasons as above. (Is sealing injectant necessary for some special services/applications?)

c. On flushing devices direct on valves. Only to be seen as necessary direct on valves if cavities in valves from construction and application could be filled or packed with unwanted material that can not be removed elswise. (Eg.: wrongly selected valvetype or necessary for some valvetypes for some applications? Only one I can think of is large gatevalves to outlign pressure before and after valve plus flushing)

 

[bcd]

The use of lubricant & sealant injection is caused by the valve design and the application it will be used in. If you have a API-6D trunion ball valve with piston type seats, you should consider the need for fittings. Soft seated floating balls generally do not use injection fittings.