butterfly valve construction and cover type

[Hashim lawati]

dear friends

i am working for a client following shell standard, so we use predefined piping classes and all components have a ready data sheet.


in a particular case of a butterfly valve data sheet, it states that type of construction is integral legging extension, and bonnet type is bottom cover. i am not sure what that means and i have some vendors who are deviating from this. i tried googling but could not find any thing useful.

the valve material body is CS and trim is rubber lining / DSS and size is 10"-24".

thanks a lot for your help.
Hashim.

 

[Hashim lawati]

guys, appreciate your help.

 

[GD2]

What's the valve standard - API 609, MSS SP 68, Cat A, B etc? What's the application - utility or process?

GDD
Canada

 

[bimr]

Lagging is an extension of the value stem ,so the handle can be operated even though the pipe has an insulated jacket (this style used rather than stansard valve).

Link

 

[Hashim lawati]

thanks for participating

service is process, flare header
valve spec is API 609

 

[GD2]

Hashim,
Are these valves be insulated? If yes, as bimr had pointed out usually there is a 2" extended neck provided for insulation.
As to bonnet type 'bottom cover' I would think the valve bottom will have a bush bearing with a retainer ring and packing ring with a bolted cover supporting the bottom part of the stem.
If your client is buying more of the earlier procured valves, try to get the picture of a bare valve (not insulated). It will explain the body construction.


GDD
Canada