DN Size Code DIM A DIM B DIM C DIM D Orifice Diameter 16 F 0.665-0.669 0.31 0.52 0.62 0.348 25 H 1.020-1.023 0.35 0.57 0.87 0.464 40 J 1.611-1.614 0.67 0.82 1.37 0.890 50 K 2.044-2.047 0.87 1.00 1.87 1.135 NOTES (DIMENSIONS TABLE) *Maximum nominal dimension for a fully open valve with no spring. Consult factory for more information.

DN PART NUMBER ALL MATL 16 VIFSS 0.7 oz. 25 VIHSS 1.6 oz. 40 VIJSS 4.1 oz. 50 VIKSS 7.0 oz. Valve weights are approximate.

Vacuum Check Valve for ISO/NW/KF/QF vacuum flange

The Vacuum Flange Insert (VI) is a vacuum check valve designed to fit between ISO/NW/KF/QF vacuum flanges designed in accordance with DIN 28403, DIN 28404, ISO 1609, and ISO 2861. It is both a centering ring and a check valve. The compact design requires no additional space in the line. Its size makes it extremely economical when compared to full-bodied valves.
The VI valve can also be used as a low-pressure relief valve under either positive or vacuum conditions by using the desired spring setting.

NOTE: USP Class VI o-rings can be supplied with certification.

Size & Dimension

DN	Size Code	DIM A	DIM B	DIM C	DIM D	Orifice Diameter
16	F	0.665-0.669	0.31	0.52	0.62	0.348
25	H	1.020-1.023	0.35	0.57	0.87	0.464
40	J	1.611-1.614	0.67	0.82	1.37	0.890
50	K	2.044-2.047	0.87	1.00	1.87	1.135

NOTES (DIMENSIONS TABLE)*Maximum nominal dimension for a fully open valve with no spring. Consult factory for more information.

Available Materials

* 316 Stainless Steel (SS)

Pressure Temperature Table

Body Material	Availability	Non-Shock Pressure-Temperature Rating
316 Stainless Steel (SS)	Standard	FULL VACUUM-ATMOSPHERIC @ 100° F

Seat material and spring material selection may limit the recommended service temperature.
See seat ratings, spring ratings, and body material ratings for their respective recommended service temperatures.
Consult the factory for reduced P-T rating above 100 °F. Standard spring material is 316 Stainless Steel.

Flow Data

PRESSURE DROP PSI

Size	Cv
16	2.4
25	4.6
40	9.5
50	20.9

FOR WATER AT 72°F

WATER FLOWRATE - GPM

Note: All flow curves and Cv values presume the valves are fully open with 1/2 PSI cracking pressure springs. Consult the factory for more information.

Valve Weights

DN	PART NUMBER	ALL MATL
16	VIFSS	0.7 oz.
25	VIHSS	1.6 oz.
40	VIJSS	4.1 oz.
50	VIKSS	7.0 oz.

Valve weights are approximate.

Seat & Cracking Pressure Options

Valve Style	Size Range	Body Materials Other Options	Allowable Seat Materials Other Options	Standard Cracking Pressures Other Options More Info.	Standard Spring Material More Info.
VI	3/4" - 1-1/2"	316 SS	AFLAS® EPDM "Metal to Metal" PTFE Buna-N Kalrez® Neoprene Viton®	1/8 PSI 1/2 PSI 1.5 PSI 3.5 PSI	316 SS
VI	2"	316 SS	AFLAS® Buna-N EPDM Kalrez® "Metal to Metal" Neoprene PTFE Viton®	1/8 PSI 1/2 PSI 1.5 PSI	316 SS