DFT: Check Valves:

SCV-R® In-Line Restrictor Check Valve

The DFT® Model SCV-R® is a corrosion resistant, dependable, versatile and economical spring-assisted, in-line check valve for applications requiring higher cracking pressures than the DFT Model SCV® check valve.
The SCV-R® is a self-contained check valve that installs directly in a pipeline.
For liquid, gas or steam.
Stainless steel construction insures a long service life.

Documentation:
Product Specifications
(139KB PDF)

Please use the form below to request a quote:

SCV-R® Check Valve

1/2” to 2” Line size
750 CWP
NPT & SW ends
Stainless steel
Inconel® X-750 spring
Spring-assisted silent closing, non-slam
Cracking Pressures: 0.8 to 40.8 psig
Horiz or vert install
Body-guided disc
Tight shutoff lapped disc & seat

The SCV-R Check Valve is a non-slam spring-assisted check valve designed for applications requiring “higher cracking pressures” than the DFT Model SCV® check valve.

Options:

316 SS springs
Body seal weld
Soft seat
Alloy 20 body & seat (ASME 300)

Hastelloy® C body & seat (ASME 300)
NPT x socket weld ends
SCV-R (higher cracking pressure)
NACE

The SCV-R check valve is a self-contained check valve that installs directly in a pipeline and contains all of the proven features of the SCV check valve.

Pressure Temperature Rating (PSIG)
Temp. (F°)	750 CWP
100	750
200	645
250	610
300	580
400	535
470	510

Materials of Construction
Component	750 CWP
Body	A351 CF8M
Seat	A351 CF8M
Disc	A240 316
Spring	Inconel® X-750
“O” Ring	Zelon (470°F max)
Spring Retainer	A479 316
Shims	A240 316

SCV-R Check Valve
Class		750 CWP
1/2"	Dim A	2.68
	Dim B	1.62
	Weight	1.1
	Cv	6
	CP	1 to 25
3/4"	Dim A	3
	Dim B	2.13
	Weight	1.5
	Cv	10
	CP	0.80 to 20
1"	Dim A	3.32
	Dim B	2.54
	Weight	1.9
	Cv	17
	CP	1.2 to 23.5
1-1/4"	Dim A	3.87
	Dim B	3.06
	Weight	3.9
	Cv	33
	CP	7.7 to 22
1-1/2"	Dim A	4.75
	Dim B	3.44
	Weight	4.7
	Cv	36
	CP	1.4 to 40.8
2"	Dim A	5
	Dim B	4.4
	Weight	7.7
	Cv	64
	CP	0.9 to 21.4
Not recommended for use on discharge of reciprocating compressors.

Check Valve Operation:

A check valve allows flow in one direction and automatically prevents back flow (reverse flow) when fluid in the line reverses direction. They are one of the few self-automated valves that do not require assistance to open and close.
Check valves are flow sensitive and rely on the line fluid to open and close. The internal disc allows flow to pass forward, which opens the valve. The disc begins closing the valve as forward flow decreases or is reversed, depending on the design. The function or purpose of a check valve is to prevent reverse flow.
Internal sealing of the check valve disc and seat relies on “reverse” line pressure as opposed to the mechanical force used for on/off valves. Because of this, allowable seat leakage rates are greater for check valves than with on/off valves.

Factors affecting check valve seat leakage include reverse pressure, medium, and what the seat material is made of, such as metal or elastomer. Metal sealing surfaces generally will allow some leakage while elastomers such as Buna-N and Viton provide bubble-tight shutoff (zero leakage).
The longest trouble-free service will come from valves sized for the application, not the line size, whereby the disc is stable against the internal stop in the open position or fully closed. When these conditions are met, no fluttering of the disc will occur (resulting in premature failure.)

Check valve internals are flow sensitive. If there is not enough flow disc movement occurs inside the valve resulting in wear, potential failure, and a higher pressure drop than calculated.

Typically, pressure drop is calculated based on the check valve being 100% open as with on/off valves. However, if the flow is not sufficient to achieve full opening, but instead, the check valve is only partially open, the pressure drop will be greater than calculated since the flow passage is restricted by the disc being in the flow path.
In this situation, a large rated Cv actually becomes detrimental to the check valve (unlike with on/off valves), resulting in fluttering of the disc and eventual failure.
Two of the most common problems with check valves are reverse flow and water hammer. In both situations, a fast-closing valve is desired.

When installing check valves, point the “flow arrow” in the direction of the flow to allow the valve to perform its function. The flow arrow can be found on the body or tag.

S C V R R E S T R I C T O R C H E C K V A L V E S S C V R R E S T R I C T O R C H E C K V A L V E S
	SCV-R IN LINE RESTRICTOR CHECK VALVES
	Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
	8317-RC010	DN 15 0.5 in	0 to 750 psig 0 to 51.7 barg	2.68 in 68 mm	1.62 in 41 mm	6	1 psig 0.069 bar
	8317-RC015						1.5 psig 0.103 bar
	8317-RC020						2 psig 0.138 bar
	8317-RC025						2.5 psig 0.172 bar
	8317-RC029						2.9 psig 0.200 bar
	8317-RC036						3.6 psig 0.248 bar
	8317-RC043						4.3 psig 0.296 bar
	8317-RC050						5 psig 0.345 bar
	8317-RC058						5.8 psig 0.400 bar
	8317-RC065						6.5 psig 0.448 bar
	8317-RC077						7.7 psig 0.531 bar
	8317-RC092						9.2 psig 0.634 bar
	8317-RC107						10.7 psig 0.738 bar
	8317-RC123						12.3 psig 0.848 bar
	8317-RC150						15 psig 1.034 bar
	8317-RC181						18.1 psig 1.248 bar
	8317-RC216						21.6 psig 1.489 bar
	8317-RC250						25 psig 1.724 bar
	Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
	8368-RC035	DN 20 0.75 in	0 to 750 psig 0 to 51.7 barg	3.00 in 76 mm	2.13 in 54 mm	10	3.5 psig 0.241 bar
	8368-RC040						4 psig 0.276 bar
	8368-RC044						4.5 psig 0.310 bar
	8368-RC050						5 psig 0.345 bar
	8368-RC056						5.6 psig 0.386 bar
	8368-RC061						6.1 psig 0.421 bar
	8368-RC066						6.6 psig 0.455 bar
	8368-RC072						7.2 psig 0.496 bar
	8368-RC077						707 psig 0.531 bar
	8368-RC082						8.2 psig 0.565 bar
	Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
	8369-RC012	DN 25 1 in	0 to 750 psig 0 to 51.7 barg	3.32 in 84 mm	2.54 in 65 mm	17	1.2 psig 0.083 bar
	8369-RC014						1.4 psig 0.097 bar
	8369-RC016						1.6 psig 0.110 bar
	8369-RC018						1.8 psig 0.124 bar
	8369-RC020						2 psig 0.138 bar
	8369-RC022						2.2 psig 0.152 bar
	8369-RC024						2.4 psig 0.165 bar
	8369-RC029						2.9 psig 0.200 bar
	8369-RC036						3.6 psig 0.248 bar
	8369-RC043						4.3 psig 0.296 bar
	8369-RC050						5 psig 0.345 bar
	8369-RC057						5.7 psig 0.393 bar
	8369-RC065						6.5 psig 0.448 bar
	8369-RC077						7.7 psig 0.531 bar
	8369-RC088						8.8 psig 0.607 bar
	8369-RC100						10 psig 0.690 bar
	8369-RC111						11.1 psig 0.765 bar
	8369-RC123						12.3 psig 0.848 bar
	8369-RC136						13.6 psig 0.938 bar
	8369-RC150						15 psig 1.034 bar
	8369-RC164						16.4 psig 1.134 bar
	8369-RC186						18.6 psig 1.282 bar
	8369-RC211						21.1 psig 1.455 bar
	8369-RC235						23.5 psig 1.620 bar
	Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
	8371-RC077	DN 32 1.25 in	0 to 750 psig 0 to 51.7 barg	3.87 in 98 mm	3.06 in 78 mm	32	7.7 psig 0.531 bar
	8371-RC088						8.8 psig 0.607 bar
	8371-RC100						10 psig 0.690 bar
	8371-RC112						11.2 psig 0.772 bar
	8371-RC124						12.4 psig 0.855 bar
	8371-RC135						13.5 psig 0.931 bar
8371-RC147	14.7 psig 1.014 bar
8371-RC159	15.9 psig 1.096 bar
Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
8373-RC020	DN 40 1.5 in	0 to 750 psig 0 to 51.7 barg	4.75 in 121 mm	3.44 in 87 mm	36	2 psig 0.138 bar
8373-RC025						2.5 psig 0.172 bar
8373-RC031						3.1 psig 0.214 bar
8373-RC036						3.6 psig 0.248 bar
8373-RC042						4.2 psig 0.290 bar
8373-RC047						4.7 psig 0.324 bar
8373-RC050						5 psig 0.345 bar
8373-RC060						6 psig 0.414 bar
8373-RC065						6.5 psig 0.448 bar
8373-RC070						7 psig 0.483 bar
8373-RC076						7.6 psig 0.524 bar
8373-RC081						8.1 psig 0.558 bar
8373-RC086						8.6 psig 0.593 bar
8373-RC100						10 psig 0.690 bar
8373-RC125						12.5 psig 0.862 bar
8373-RC132						13.2 psig 0.910 bar
8373-RC139						13.9 psig 0.958 bar
8373-RC146						14.6 psig 1.007 bar
8373-RC151						15.1 psig 1.041 bar
8373-RC160						16 psig 1.103 bar
8373-RC167						16.7 psig 1.151 bar
8373-RC174						17.4 psig 1.200 bar
8373-RC181						18.1 psig 1.248 bar
8373-RC188						18.8 psig 1.296 bar
8373-RC197						19.7 psig 1.358 bar
Part #	Size	Cold Working Pressure	Dimension A	Dimension B	Cv	Cracking Pressure CP
8374-RC009	DN 50 2 in	0 to 750 psig 0 to 51.7 barg	5.00 in 127 mm	4.4 in 112 mm	64	0.9 psig 0.062 bar
8374-RC013						1.3 psig 0.090 bar
8374-RC016						1.6 psig 0.110 bar
8374-RC019						1.9 psig 0.131 bar
8374-RC023						2.3 psig 0.159 bar
8374-RC027						2.7 psig 0.186 bar
8374-RC034						3.4 psig 0.234 bar
8374-RC037						3.7 psig 0.255 bar
8374-RC040						4 psig 0.276 bar
8374-RC043						4.3 psig 0.296 bar
8374-RC047						4.7 psig 0.324 bar
8374-RC052						5.2 psig 0.359 bar
8374-RC066						6.6 psig 0.455 bar
8374-RC074						7.4 psig 0.510 bar
8374-RC083						8.3 psig 0.572 bar
8374-RC091						9.1 psig 0.627 bar
8374-RC100						10 psig 0.690 bar
8374-RC120						12 psig 0.827 bar