About Backflow-Prevention Valves
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About Pressure-Relief Valves
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Plastic Panel-Mount Vacuum-Regulating Valves for Air and Inert Gas

- For Use With: Air, Inert Gas
- Temperature Range: 40° to 150° F
A lighter and more corrosion-resistant alternative to metal valves. All valves throttle a high vacuum source to maintain a lower vacuum level in your system. Adjust the outlet vacuum level within the range. Threads below the adjustment knob and an included panel-mount nut let you add these valves to your instrument panel. All are constant-bleed style, so they continually release small amounts of process gas to improve accuracy and repeatability.
For technical drawings and 3-D models, click on a part number.
Inlet | Outlet | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Pipe Size | Thread Size | Location | Pipe Size | Thread Size | Location | Vacuum Range, in. of Hg | Vacuum Adjustment Method | End-to-End Lg. | Panel Cutout Dia. | Each | |
NPT Female | |||||||||||
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal | |||||||||||
1/8 | __ | Side | 1/8 | __ | Side | 0 to 30 | Knob | 1 9/16" | 9/16" | 00000000 | 000000 |
UNF Female | |||||||||||
Polysulfone Body—Buna-N/EPDM Diaphragm and Polyurethane Seal | |||||||||||
__ | 10-32 | Side | __ | 10-32 | Side | 0 to 30 | Knob | 1 1/8" | 9/16" | 00000000 | 00000 |
High-Accuracy Panel-Mount Vacuum-Regulating Valves for Air and Inert Gas

- For Use With: Air, Argon, Nitrogen
- Temperature Range: -40° to 165° F
For precise control over your vacuum level, these valves have ±0.1% accuracy. They throttle a high vacuum source to maintain a lower vacuum level in your system. Adjust the outlet vacuum level within the range. Valves have threads below the adjustment knob and come with a panel-mount nut. All have a gauge port. They are constant-bleed style, so they continually release small amounts of process gas to improve accuracy and repeatability.
For technical drawings and 3-D models, click on a part number.
Extended-Life Vacuum-Regulating Valves for Air and Inert Gas

- For Use With: Air, Inert Gas
- Temperature Range: -20° to 180° F
For a longer service life than brass vacuum-regulating valves, these are made of bronze for strength and durability. They throttle a high vacuum source to maintain a lower vacuum level in your system. Turning the adjustment screw will adjust the vacuum setting.
For technical drawings and 3-D models, click on a part number.
Inlet | Outlet | |||||||
---|---|---|---|---|---|---|---|---|
Pipe Size | Location | Pipe Size | Location | Vacuum Range, in. of Hg | Vacuum Adjustment Method | End-to-End Lg. | Each | |
NPT Female | ||||||||
Bronze Body—Neoprene Diaphragm and Chrome-Plated Bronze Seal | ||||||||
1/2 | Side | 1/2 | Side | 2 to 30 | Screw | 2 7/8" | 0000000 | 0000000 |
3/4 | Side | 3/4 | Side | 2 to 30 | Screw | 2 7/8" | 0000000 | 000000 |
1 | Side | 1 | Side | 2 to 30 | Screw | 4 1/2" | 0000000 | 00000000 |
1 1/4 | Side | 1 1/4 | Side | 2 to 30 | Screw | 4 1/2" | 0000000 | 00000000 |
1 1/2 | Side | 1 1/2 | Side | 8 to 30 | Screw | 5 3/4" | 0000000 | 00000000 |
2 | Side | 2 | Side | 8 to 30 | Screw | 5 3/4" | 0000000 | 00000000 |
Vacuum-Regulating Valves for Air and Inert Gas

- For Use With: Air, Carbon Dioxide, Inert Gas, Nitrogen
- Temperature Range: -20° to 180° F
Throttle a high vacuum source to maintain a lower vacuum level in your system. Adjust the outlet vacuum level within the range. All valves have a gauge port.
For technical drawings and 3-D models, click on a part number.
Adjustable Vacuum-Relief Valves for Air and Inert Gas

- For Use With: Air, Inert Gas
- Temperature Range: -15° to 250° F
These valves begin opening at the set vacuum level and fully open at about 10% over the set point. They begin closing as the vacuum level drops and fully close when the system is restored below the set point. Adjust the set vacuum level within the range. Valves have a vented relief port to exhaust discharge directly.
For technical drawings and 3-D models, click on a part number.
Inlet | Set Vacuum | ||||||
---|---|---|---|---|---|---|---|
Pipe Size | Location | Relief Port Location | Range , in. of Hg | Adjustment Method | Overall Ht. | Each | |
NPT Male Inlet and Relief Vent | |||||||
Brass Body—440C Stainless Steel Seal | |||||||
1/4 | Bottom | Top | 0 to 27 | External Adjustment Screw | 1 3/4" | 00000000 | 00000 |
Brass Body—Buna-N Seal | |||||||
3/8 | Bottom | Top | 0 to 27 | External Adjustment Screw | 2 1/16" | 00000000 | 00000 |
3/4 | Bottom | Top | 0 to 27 | External Adjustment Screw | 2 5/8" | 00000000 | 00000 |
Compact Flange-Mount Check Valves


- For Use With: Air, Argon, Helium, Krypton, Neon, Water, Xenon
- Piston Material: 316 Stainless Steel
- Spring Material: 316 Stainless Steel
- Seal Material: Viton® Fluoroelastomer
Less than half the end-to-end length of standard flange-mount check valves, these can be installed between ANSI flanges in pipelines with limited clearance. ANSI flanges are sold separately. Valves open to allow flow in one direction and close when flow stops or reverses. All have a 316 stainless steel body for excellent corrosion resistance.
Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.
For technical drawings and 3-D models, click on a part number.
Pipe Size | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | End-to-End Lg. | For Flange Class | Each | |
316 Stainless Steel Body | ||||||||
---|---|---|---|---|---|---|---|---|
Flanged × Flanged | ||||||||
1/2 | 2.4 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 0000000 |
3/4 | 4.4 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 000000 |
1 | 6.1 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 000000 |
1 1/4 | 12.7 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 000000 |
1 1/2 | 18.8 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 000000 |
2 | 32 | 720 psi @ 100° F | 0.5 | -10° to 400° | 1/4" | 150, 300 | 0000000 | 000000 |
3 | 89 | 720 psi @ 100° F | 0.5 | -10° to 400° | 5/16" | 150, 300 | 0000000 | 000000 |
4 | 144 | 720 psi @ 100° F | 0.5 | -10° to 400° | 3/8" | 150, 300 | 0000000 | 000000 |
Butt-Weld Check Valves

- For Use With: Air, Argon, Helium, Krypton, Neon, Water, Xenon
- Piston Material: 316 Stainless Steel
- Spring Material: 316 Stainless Steel
- Seal Material: Viton® Fluoroelastomer
Weld these valves to unthreaded pipe for a smooth, flush connection that provides maximum flow. All open to allow flow in one direction and close when flow stops or reverses. They have a 316 stainless steel body for excellent corrosion resistance.
Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.
For technical drawings and 3-D models, click on a part number.
Pipe Size | For Pipe Schedule | Flow Coefficient (Cv) | Max. Pressure | Min. Opening Pressure, psi | Temperature Range, °F | End-to-End Lg. | Specifications Met | Each | |
316 Stainless Steel Body | |||||||||
---|---|---|---|---|---|---|---|---|---|
Butt Weld × Butt Weld | |||||||||
1/2 | 40 | 2.4 | 1,500 psi @ 100° F | 0.5 | -10° to 400° | 2 3/16" | ANSI/ASME B16.25 | 0000000 | 0000000 |
3/4 | 40 | 4.4 | 1,500 psi @ 100° F | 0.5 | -10° to 400° | 2 11/16" | ANSI/ASME B16.25 | 0000000 | 000000 |
1 | 40 | 6.1 | 1,500 psi @ 100° F | 0.5 | -10° to 400° | 2 15/16" | ANSI/ASME B16.25 | 0000000 | 000000 |
1 1/2 | 40 | 18.8 | 1,500 psi @ 100° F | 0.5 | -10° to 400° | 3 15/16" | ANSI/ASME B16.25 | 0000000 | 000000 |
2 | 40 | 32 | 1,500 psi @ 100° F | 0.5 | -10° to 400° | 4 3/8" | ANSI/ASME B16.25 | 0000000 | 000000 |
Vacuum-Breaking Valves
Also known as vacuum breakers, these valves have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping.
303 stainless steel valves have the best corrosion resistance.
Straights are often used with steam coils, heat exchangers, and space heaters.
For technical drawings and 3-D models, click on a part number.

- For Use With: Air, Argon, Helium, Krypton, Neon, Steam, Water, Xenon
- Seal Material: EPR Rubber
Inlet Pipe Size | Outlet Pipe Size | Max. Pressure | Temperature Range, °F | End-to-End Lg. | Body Material | Each | |
Brass Body | |||||||
---|---|---|---|---|---|---|---|
NPT Male Inlet × NPT Female Outlet | |||||||
1/2 | 3/8 | 300 psi @ 70° F | -20° to 365° | 1 3/4" | Brass | 0000000 | 0000000 |
3/4 | 1/2 | 300 psi @ 70° F | -20° to 365° | 2 1/8" | Brass | 0000000 | 000000 |
1 | 3/4 | 300 psi @ 70° F | -20° to 365° | 2 3/8" | Brass | 0000000 | 000000 |
303 Stainless Steel Body | |||||||
NPT Male Inlet × NPT Female Outlet | |||||||
1/2 | 3/8 | 300 psi @ 70° F | -20° to 365° | 1 3/4" | 303 Stainless Steel | 0000000 | 000000 |
3/4 | 1/2 | 300 psi @ 70° F | -20° to 365° | 2 1/8" | 303 Stainless Steel | 0000000 | 000000 |
1 | 3/4 | 300 psi @ 70° F | -20° to 365° | 2 3/8" | 303 Stainless Steel | 0000000 | 000000 |
High-Pressure Vacuum-Breaking Valves

- For Use With: Air, Argon, Helium, Krypton, Neon, Oil, Water, Xenon
- Seal Material: Fluoroelastomer Rubber
Rated for 12 times the pressure of standard vacuum-breaking valves, these can handle up to 1,500 psi. Also known as vacuum breakers, they have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping. Body is 316 stainless steel for excellent corrosion resistance.
Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.
For technical drawings and 3-D models, click on a part number.
Vacuum-Breaking Valves for Chemicals

A plastic body withstands pH neutralizing, cleaning, and plating solutions containing sodium hydroxide, methyl ethyl ketone, and other harsh chemicals. Also known as vacuum breakers, these valves have vents that open when pressure drops to relieve vacuum conditions and prevent backward suction from drawing liquid into upstream piping.
For technical drawings and 3-D models, click on a part number.
- For Use With: Air, Ammonia, Argon, Beverage, Carbon Dioxide, Chlorinated Water, Diesel Fuel, Drinking Water, Ethylene Glycol, Food, Helium, Hydrochloric Acid, Kerosene, Krypton, Liquid Carbon Dioxide, Methanol, Methyl Ethyl Ketone, Mineral Spirits, Natural Gas, Neon, Nitric Acid, Nitrogen, Oil, Oxygen, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water, Xenon
- Diaphragm Material: Fluoroelastomer Rubber
- Seal Material: Fluoroelastomer Rubber
Pipe Size | For Pipe Schedule | Max. Pressure | Min. Opening Pressure, psi | End-to-End Lg. | Color | Temperature Range, °F | Each | |
PVC Plastic Body | ||||||||
---|---|---|---|---|---|---|---|---|
NPT Female × NPT Female | ||||||||
1/2 | 80 | 100 psi @ 75° F | 1 | 4 5/16" | Gray | 40° to 140° | 000000 | 0000000 |
3/4 | 80 | 100 psi @ 75° F | 1 | 4 5/8" | Gray | 40° to 140° | 0000000 | 000000 |
1 | 80 | 100 psi @ 75° F | 1 | 5 1/8" | Gray | 40° to 140° | 0000000 | 000000 |
CPVC Plastic Body | ||||||||
NPT Female × NPT Female | ||||||||
1/2 | 80 | 100 psi @ 75° F | 1 | 4 5/16" | Light Gray | 40° to 180° | 0000000 | 000000 |
3/4 | 80 | 100 psi @ 75° F | 1 | 4 5/8" | Light Gray | 40° to 180° | 0000000 | 000000 |
1 | 80 | 100 psi @ 75° F | 1 | 5 1/8" | Light Gray | 40° to 180° | 0000000 | 000000 |
- For Use With: Air, Ammonia, Argon, Beverage, Carbon Dioxide, Chlorinated Water, Diesel Fuel, Drinking Water, Ethylene Glycol, Food, Helium, Hydrochloric Acid, Kerosene, Krypton, Liquid Carbon Dioxide, Methanol, Methyl Ethyl Ketone, Mineral Spirits, Natural Gas, Neon, Nitric Acid, Nitrogen, Oil, Oxygen, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water, Xenon
- Piston Material:
PVC Plastic Body: PVC Plastic
CPVC Plastic Body: CPVC Plastic - Spring Material: Plastic Polymer
- Seal Material: Fluoroelastomer Rubber
Pipe Size | For Pipe Schedule | Max. Pressure | Min. Opening Pressure, psi | End-to-End Lg. | Color | Temperature Range, °F | Each | |
PVC Plastic Body | ||||||||
---|---|---|---|---|---|---|---|---|
NPT Female × NPT Female | ||||||||
2 | 80 | 100 psi @ 75° F | 1 | 8 1/2" | Gray | 40° to 140° | 0000000 | 0000000 |
CPVC Plastic Body | ||||||||
NPT Female × NPT Female | ||||||||
1 1/2 | 80 | 100 psi @ 75° F | 1 | 7 15/16" | Light Gray | 40° to 180° | 0000000 | 000000 |