Universal Low-Pressure Check Valve Style – U3, UR

Description

The Universal Low Pressure (U3, UR) female threaded check valve is a one-piece body machined from bar stock and is designed for minimum pressure drop. The valve is light-weight, compact, and provides maintenance-free dependable service. NPT threads are per ASME B1.20.1 and this valve is also available with ISO 7 “Rp” threads (UR). For applications above 3000 PSIG, view our UN-10 series. For applications where weld joint are required view our UN-SW series.

Many valves in this series can be supplied with B16.34 certification. Give us a call for more information.

Size & Dimension

Nominal Pipe SizeSize CodeAHEX SIZE BC**Orifice Diameter
3/8C2.1613/163/8 NPT0.348
1/2D2.711-11/2 NPT0.464
3/4F2.951-1/43/4 NPT0.593
1H3.641-5/81 NPT0.890
1-1/4I3.912-1/41-1/4 NPT1.135
1-1/2J4.362-121-1/21.385
2K5.8532 NPT1.555
2-1/2L5.503-3/42-1/2 NPT1.555
3M6.254-1/23 NPT2.025
4N7.135-1/24 NPT2.560

NOTES (DIMENSIONS TABLE)*May be larger and/or round.
**Consult factory for ISO 7 "Rp" threads.

Available Materials

* 316 Stainless Steel (SS)* Alloy B (HB)
* Alloy 20 (A2)* Alloy C-276 (HC)
* Brass (BR)* Alloy 400 or MONEL® (MO)
* Carbon Steel (CS)* Alloy 400 or MONEL® (MO)
* Titanium (TI)

Pressure Temperature Table

Body MaterialAvailabilityNon-Shock Pressure-Temperature Rating 
316 Stainless Steel (SS)
Carbon Steel (CS)
Brass (BR)
Standard3/8" - 3"
3000 PSIG @ 100°F
(1500 PSIG for o-ring seats)
4"
1500 PSIG @ 100°F
Alloy 20 (A2)
Alloy C-276 (HC)
Alloy 400 or MONEL®(MO)
Semi-standard
Alloy B (HB)
Titanium (TI)
Contact the factory for these or other materials.

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

SizeCv
3/81.9
1/24.3
3/47.2
114.6
1-1/428.8
1-1/231.9
242.0
2-1/250.0
389.0
4140

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

SIZEPART NUMBERSS, CS & AlloysBRASS
3/8U3C3.0 oz.3.3 oz.
1/2U3D8.5 oz.9.1 oz.
3/4U3F9.6 oz.10.1 oz.
1U3H1.2 lb.1.3 lb.
1-1/4U3I2.9 lb.3.2 lb.
1-1/2U3J3.6 lb.3.9
2U3K6.5 lb.7.2 lb.
2-1/2U3L9.2 lb.10 lb.
3U3M14.3 lb.15.5 lb.
4U3N21.7 lb.23.9 lb.

Seat & Cracking Pressure Options

Valve StyleSize RangeBody Materials
Other Options
Allowable Seat Materials
Other Options
Standard Cracking Pressures.
Other Options
More Info.
Standard Spring Material
More Info.
U33/8" -1-1/4"316 SS BrassAFLAS®
EPDM
"Metal to Metal"
PTFE

Buna-N
Kalrez®
Neoprene
Viton®
1/8 PSI
1/2 PSI
1.5 PSI
3.5 PSI
316 SS
U33/8" - 1-1/4"C. SteelAFLAS®
Buna-N
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/8 PSI
1/2 PSI
1.5 PSI
3.5 PSI
316 SS
U31-1/2" - 2"316SS
Brass
AFLAS®
Buna-N
EPDM
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/8 PSI
1/2 PSI
1.5 PSI
316 SS
U31-1/2" - 2"C. SteelAFLAS®
Buna-N
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/8 PSI
1/2 PSI
1.5 PSI
316 SS
U33/8" - 2"Alloy 20
Alloy C-276
AFLAS®
Buna-N
EPDM
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/2 PSIAlloy C-276
U33/8" - 2"Alloy 400 or MONEL®AFLAS®
Buna-N
EPDM
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/2 PSIAlloy 400 or MONEL®
U33/8" - 2"Alloy BAFLAS®
Buna-N
EPDM
Kalrez®
"Metal to Metal"
Neoprene
PTFE
Viton®
1/2 PSIAlloy B

For additional information about Check Valves

What is a Silent Check Valve?
What is a Spring Loaded Check Valve?
What is a Poppet Check Valve?

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