[ Using 1500 # inlet flange instead of 300 # flange ] 3

[gguliye]

Dear All,
The pressure relief valves come with the different orifices and each orifice has the fixed flange rating based on API. However, in my case, the customer would like to deviate from API flange ratings
The customer requires J orifice with 300 # inlet and 300 # outlet. However, the existing J orifice flange rating is 1500 # inlet flange. Can we bolt 1500 # inlet flange with 300 # flange bolting so the valve will match with the existing tube?
regards,

 

[The Obturator]

No. 3" 1500# Rating will not mate with 300#.
Dependant on service conditions, you have a choice;
i) Machine standard 300 x 150 SRV with a cosmetic 300 outlet (ie., will fit holes only but will not be rated to 300#).
ii) Get manufacturer to modify body casting to have fully dimensional 300# outlet - still not fully rated, but meets OD of flange.
iii) Request vendor if he can machine his 1500# inlet to a 300# inlet from a standard 3J4 1500 x 300 SRV to meet API outlet rating.
iV) Dependant on manufacturer and design, use a standard 300 x 150 pilot operated SRV with modified outlet. SOME manufacturers have their standard 150# outlet design POSRV's core body actually rated to 300#. Note POSRV may have different centre to face dimensions.
In all cases confer with the manufacturer for availability and compatibility with the application. In all cases, this would be a special and price and delivery time will be affected.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[gguliye]

AVALVEMAN,
manufacturer is Crosby. have u ever seen such a design?
regards,

 

[The Obturator]

Yes. All the time when I worked there. Not sure how they would answer you now. The impression I get these days, from everywhere. is that if the catalogue/computer/sizing programme etc., says No, then they'll say no also. In your case its all dependant on the service conditions you have and what is acceptable to the customer, as per the above choices. Get the right one then go to the vendor and tell them what you want.

Per ISO, only the term Safety Valve is used regardless of application or design.

 

[gguliye]

Thanks valveman

 

[mk3223]

IMO, you may request the vendor to make the valve other than the standard sizes, but it may come down to the cost if worth for the project.

 

[gerhardl]

Cheapest is to machine a single barstock piece with 300 throughlet, face oneside with mounted pinbolts to fit 300 flange, other side with pinbolts to fit 1500. Better (since the valve seems to be mounted some distance before end of pipe) to use a similar mounting piece with different endflanges.

Both are normal solutions, supplied fast and relatively cheap from specialized subsuppliers worldwide, with all sertificates required. You can of course not let one flange deviate down from the required valve pressure class, while upward deviation is OK.