Check Valve Installation: Best Practice – Straight Pipe Requirements

1. Many designers are not aware of the Check Valve Installation: Best Practice – Straight Pipe Requirements.
If you download the Goodwin- Catalogue.pdf from the link below and go to Page 58, you will see the recommended practice. Note although the diagrams show Dual Plate Check Valves, i believe this Practice applies to all types of Check Valve. See further references stated below.

http://www.checkvalves.co.uk/brochure_downloads.html

Quite often 2 check valves are installed in series, usually dissimilar types, this is not covered by the best practice.
I would assume you may possibly class the 2nd Check Valve as a Throttling valve, and may therefore need straight requirements between them, BUT THIS NEEDS CONFIRMING or CLARIFYING?
Also for 2 dissimilar types, is there a preferance for which one should be installed upstream?
I believe the reason for this practice is the wear, tear and fatigue of the hinge pin. This is designed for specified lifecycles, based on periodic operation cycles. However, if the Check Valve is installed in a turbulent area of flow, then it will instead be continous operation cycles, and so the lifespan will be considerably reduced.

2, Also refer to ASME Publication 82-PET-12]https://www.youtube.com/watch?v=ZlrFMmGs_NI[/url]

Cavitation in a Globe Valve
https://www.youtube.com/watch?v=vRk1SWucy1s

4. Section 1.3 Page G17 of the Flowserve-Edwards Valve Document below summarises even greater straight pipe requirements for check valves in specific configurations.

http://flowserve.com/vgnfiles/Files/Lit … Sect.G.pdf