I posted a 3″ Swing Check Valve on GrabCad today. Within a couple of hours, it got 6 likes and 3 downloads. And if you didn’t know…all downloads on GrabCad are free.
This valve is manufactured by KITZ. It has class 300 raised face flanges and the body is made from cast stainless steel. The face to face dimension is 12.5″.
The KITZ number is 300UOAM3 316SS GRAFOIL C.E.
Link: https://www.kitzus-kca.com/industrial-check-valves.php
The model does not have any internals. You can use it for system design.
Link: https://grabcad.com/library/3-flanged-check-vavle-1
This is a rendering of the valve created in SolidWorks 2017
Below is a photo of the valve. 
Below is a generic cross section from the KITZ web site. When you look inside, you can see the are and disc that rotate up when the flow is from the left to the right. When there is no flow or the flow is going from right to left, the arm swings down and the dick closes the valve.
After nearly 1 day, 14 likes and 11 downloads.
Simmer3D 