Check Valves for Oxygen | McMaster-Carr

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47 Products

About Backflow-Prevention Valves

Assembled View

Exploded View

To reduce installation time and allow for maintenance without detaching pipe connections, these valves have union fittings. The plastic body and fluoroelastomer seal provide excellent chemical resistance. Valves open to allow flow in one direction and close when flow stops or reverses.

PVC and CPVC valves come with unthreaded socket-connect female fittings in addition to the threaded NPT female fittings.

Polypropylene valves are more corrosion resistant than PVC or CPVC valves.

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.

PVC Plastic Body

For Use With:
BSPP thread type:
Butane, Kerosene, Liquid Carbon Dioxide, Natural Gas, Nitric Acid, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Water
NPT thread type:
Citric Acid, Diesel Fuel, Drinking Water, Ethylene Glycol, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Nitric Acid, Oil, Phosphoric Acid, Salt Water, Sodium Hypochlorite, Water
Ball Material: PVC Plastic
Seal Material: Fluoroelastomer Rubber

BSPP Female × BSPP Female
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.	Specifications Met		Each
1/2	6.3	150 psi @ 70° F	1	40° to 140°	Dark Gray	4 1/4"	ASTM D1784	0000000	0000000
1	25	150 psi @ 70° F	1	40° to 140°	Dark Gray	5 3/16"	ASTM D1784	0000000	000000

Polypropylene Plastic Body

For Use With: Air, Ammonia, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Ethanol, Ethylene Glycol, Isopropyl Alcohol, Kerosene, Methanol, Natural Gas, Oil, Oxygen, Phosphoric Acid, Salt Water, Soap Solutions, Sodium Hydroxide, Water
Ball Material: Polypropylene Plastic
Seal Material: Fluoroelastomer Rubber

NPT Female × NPT Female
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.	Specifications Met		Each
1/2	4.8	150 psi @ 70° F	1	35° to 160°	White	4 11/16"	ASTM D4101	0000000	0000000
3/4	7.7	150 psi @ 70° F	1	35° to 160°	White	4 3/4"	ASTM D4101	0000000	000000
1	11	150 psi @ 70° F	1	35° to 160°	White	5 3/8"	ASTM D4101	0000000	000000
1 1/2	45	150 psi @ 70° F	1	35° to 160°	White	6 3/4"	ASTM D4101	0000000	000000
2	130	150 psi @ 70° F	1	35° to 160°	White	8 1/8"	ASTM D4101	0000000	000000

Threaded Check Valves for Harsh Chemicals

These valves open to allow flow in one direction and close when flow stops or reverses.

Valves for drinking water meet NSF/ANSI Standard 61.

Polypropylene valves are more corrosion resistant than PVC or CPVC valves.

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.

PVDF Plastic Body—Spring-Loaded Ball

For Use With: Air, Ammonia, Butane, Carbon Dioxide, Chlorine, Citric Acid, Deionized Water, Diesel Fuel, Ethylene Glycol, Fuel Oil, Gasoline, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Natural Gas, Nitric Acid, Oil, Oxygen, Phosphoric Acid, Propane, Salt Water, Sodium Hydroxide, Toluene, Water, Xylene
Ball Material: 316 Stainless Steel
Spring Material: 316 Stainless Steel
Seal Material: Fluoroelastomer Rubber

NPT Male × NPT Male
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.		Each
1/8	Not Rated	220 psi @ 70° F	2.5	40° to 180°	White	1"	00000000	000000
1/4	Not Rated	220 psi @ 70° F	2.5	40° to 180°	White	1 7/16"	00000000	00000
3/8	Not Rated	220 psi @ 70° F	2.5	40° to 180°	White	1 1/2"	00000000	00000
1/2	Not Rated	220 psi @ 70° F	2.5	40° to 180°	White	1 13/16"	00000000	00000

PVC Plastic Body—Ball

For Use With: Air, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Diesel Fuel, Drinking Water, Ethanol, Ethylene Glycol, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Methanol, Mineral Spirits, Natural Gas, Oil, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Water
Ball Material: PVC Plastic
Seal Material: Fluoroelastomer Rubber

NPT Female × NPT Female
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.	Specifications Met		Each
1/4	1	150 psi @ 70° F	1.5	35° to 140°	Dark Gray	3"	ASTM D1784, NSF/ANSI 61	0000000	000000
3/8	3	150 psi @ 70° F	1.5	35° to 140°	Dark Gray	3"	ASTM D1784, NSF/ANSI 61	0000000	00000
3	250	150 psi @ 70° F	1.5	35° to 140°	Dark Gray	10 9/16"	ASTM D1784, NSF/ANSI 61	0000000	000000
4	400	150 psi @ 70° F	1.5	35° to 140°	Dark Gray	12 15/16"	ASTM D1784, NSF/ANSI 61	0000000	000000

CPVC Plastic Body—Ball

For Use With: Air, Butane, Carbon Dioxide, Citric Acid, Deionized Water, Diesel Fuel, Drinking Water, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Mineral Spirits, Natural Gas, Nitric Acid, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Sulfuric Acid, Water
Ball Material: CPVC Plastic
Seal Material: Fluoroelastomer Rubber

NPT Female × NPT Female
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.	Specifications Met		Each
3	250	150 psi @ 70° F	1.5	35° to 190°	Dark Gray	10 9/16"	ASTM D1784, NSF/ANSI 61	0000000	0000000
4	400	150 psi @ 70° F	1.5	35° to 190°	Dark Gray	12 15/16"	ASTM D1784, NSF/ANSI 61	0000000	00000000

Ultra-Chemical-Resistant Threaded Check Valves

Female × Female

Female × Male

Male × Female

Male × Male

For Use With: Acetone, Ammonia, Butane, Carbon Dioxide, Citric Acid, Diesel Fuel, Ethylene Glycol, Fuel Oil, Gasoline, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Methanol, Methyl Ethyl Ketone, Mineral Spirits, Natural Gas, Nitric Acid, Nitrogen, Oil, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hydroxide, Sodium Hypochlorite, Sulfuric Acid, Toluene, Water, Xylene
Piston Material: PTFE Plastic
Spring Material: PTFE Plastic

The most chemical-resistant check valves in our offering, these have a PFA body to withstand methyl ethyl ketone, sodium hypochlorite, and other extremely harsh chemicals. They open to allow flow in one direction and close when flow stops or reverses.

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.

PFA Plastic Body
Pipe Size	Flow Coefficient (Cv)	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.		Each
NPT Female × NPT Female
1/4	0.75	125 psi @ 150° F	1	0° to 210°	Semi-Clear White	2 3/8"	00000000	0000000
1/2	4	100 psi @ 150° F	1	0° to 210°	Semi-Clear White	3 3/8"	00000000	000000
NPT Female × NPT Male
1/4	0.75	125 psi @ 150° F	1	0° to 210°	Semi-Clear White	2 7/16"	00000000	000000
NPT Male × NPT Female
1/4	0.75	125 psi @ 150° F	1	0° to 210°	Semi-Clear White	2 1/16"	00000000	000000
NPT Male × NPT Male
1/4	0.75	125 psi @ 150° F	1	0° to 210°	Semi-Clear White	2 7/16"	00000000	000000

Check Valves with Push-to-Connect Fittings for Harsh Chemicals

For Use With: Air, Argon, Butane, Carbon Dioxide, Chlorine, Citric Acid, Deionized Water, Diesel Fuel, Ethanol, Ethylene Glycol, Gasoline, Helium, Hydrochloric Acid, Isopropyl Alcohol, Kerosene, Krypton, Mineral Spirits, Natural Gas, Neon, Nitric Acid, Nitrogen, Oil, Oxygen, Phosphoric Acid, Propane, Salt Water, Soap Solutions, Sodium Hypochlorite, Sulfuric Acid, Toluene, Water, Xenon, Xylene
Piston Material: PVDF Plastic
Spring Material: Stainless Steel
Seal Material: Fluoroelastomer Rubber

Connect your outlet tubing into the push-to-connect fittings—no heat, solder, or flux required. These valves have a PVDF body and a fluoroelastomer seal for excellent chemical resistance. They open to allow flow in one direction and close when flow stops or reverses.

For technical drawings and 3-D models, click on a part number.

PVDF Plastic Body
For Tube OD	Pipe Size	Max. Pressure	Min. Opening Pressure, psi	Temperature Range, °F	Color	End-to-End Lg.		Each
Push-to-Connect Inlet × NPTF Male Outlet
3/8"	1/4	300 psi @ 70° F	0.5	0° to 250°	Black	1 3/8"	0000000	000000

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.

Diaphragm

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

PVC Plastic Body
Pipe Size	For Pipe Schedule	Max. Pressure	Min. Opening Pressure, psi	End-to-End Lg.	Color	Temperature Range, °F		Each
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

Spring-Loaded Piston

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

PVC Plastic Body
Pipe Size	For Pipe Schedule	Max. Pressure	Min. Opening Pressure, psi	End-to-End Lg.	Color	Temperature Range, °F		Each
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

Welding Gas Check Valves for Regulators

Stop the reverse flow of gas in your regulator. Check valves do not stop flashbacks.

Max. Pressure, psi	Male Hose Connection			Male Pipe Connection
Oxygen	Thread Direction	Thread Size	Thread Type	Thread Direction	Pipe Size	Thread Type	Material		Each
125	Right Hand	9/16"-18	UNF	Right Hand	1/4	NPT	Brass	000000	000000

Welding Gas Check Valves for Torches

Stop the reverse flow of gas in your torch. Check valves do not stop flashbacks.

Max. Pressure, psi	Male Hose Connection			Female Hose Connection
Oxygen	Thread Direction	Thread Size	Thread Type	Thread Direction	Thread Size	Thread Type	Material		Each
125	Right Hand	3/8"-24	UNF	Right Hand	3/8"-24	UNF	Brass	000000	000000
125	Right Hand	9/16"-18	UNF	Right Hand	9/16"-18	UNF	Brass	000000	00000

Welding Gas Flashback Arresters for Regulators

Standard and High Flow

Quick Disconnect

Attach these arresters to the outlet connection of a regulator on a torch that cuts steel up to 11" thick. Arresters extinguish flames and have a check valve to stop reverse gas flow. They are reusable; resetting is not required after flashback.

Arresters with right-hand threads are for use with oxygen. Arresters with left-hand threads are for use with acetylene, hydrogen, and propane.

High-flow arresters give you twice the airflow rate compared to standard flashback arresters when they’re used at the same inlet pressure. They are often used with larger torch tips.

Quick-disconnect arresters have a fitting that connects and disconnects them from your torch, so you don't have to thread these arresters on and off with a wrench.

Right-Hand Threads—UNF Male × UNF Female

Standard
Thread Size	Max. Pressure for Oxygen, psi	Material	Specifications Met		Each
3/8"-24	143	Brass	EN 730, ISO 5175	0000000	000000
9/16"-18	143	Brass	EN 730, ISO 5175	00000000	00000
High Flow
9/16"-18	143	Brass	EN 730, ISO 5175	00000000	000000
7/8"-14	143	Brass	EN 730, ISO 5175	00000000	000000
Quick Disconnect
9/16"-18	143	Brass	EN 561, ISO 7289	00000000	000000

Right-Hand and Left-Hand Threads—UNF Male × UNF Female

	Max. Pressure, psi
Thread Size	Oxygen	Acetylene	Hydrogen	Propane	Material	Specifications Met		Pair
Standard
9/16"-18	143	15	50	50	Brass	EN 730, ISO 5175	00000000	0000000

NPT Female × NPT Female

Standard
Pipe Size	Max. Pressure for Oxygen, psi	Material	Specifications Met		Each
1/4	143	Brass	EN 730, ISO 5175	00000000	0000000

Welding Gas Flashback Arresters for Torches

Standard and High Flow

Quick Disconnect

These arresters attach directly to torches that cut steel up to 8" thick. They extinguish flames and have a check valve to stop reverse gas flow. They are reusable; resetting is not required after flashback.

Arresters with right-hand threads are for use with oxygen; arresters with left-hand threads are for use with acetylene, hydrogen, and propane.

High-flow arresters give you twice the airflow rate compared to standard flashback arresters when they’re used at the same inlet pressure. They are often used with larger torch tips.

Quick-disconnect arresters have a fitting that connects and disconnects them from your torch, so you don't have to thread these arresters on and off with a wrench.

With Right-Hand Threads

Male Hose Connection		Female Hose Connection
Thread Size	Thread Type	Thread Size	Thread Type	Max. Pressure for Oxygen, psi	Material	Specifications Met		Each
Standard
9/16"-18	UNF	9/16"-18	UNF	143	Brass	EN 730, ISO 5175	00000000	000000
High Flow
3/8"-24	UNF	3/8"-24	UNF	143	Brass	EN 730, ISO 5175	0000000	00000
9/16"-18	UNF	9/16"-18	UNF	143	Brass	EN 730, ISO 5175	00000000	000000
7/8"-14	UNF	7/8"-14	UNF	143	Brass	EN 730, ISO 5175	00000000	000000
Quick Disconnect
9/16"-18	UNF	9/16"-18	UNF	143	Brass	EN 561, ISO 7289	00000000	00000

With Right-Hand and Left-Hand Threads

Male Hose Connection		Female Hose Connection		Max. Pressure, psi
Thread Size	Thread Type	Thread Size	Thread Type	Oxygen	Acetylene	Hydrogen	Propane	Material	Specifications Met		Pair
Standard
9/16"-18	UNF	9/16"-18	UNF	143	15	50	50	Brass	EN 730, ISO 5175	00000000	0000000

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About Backflow-Prevention Valves

Easy-to-Install Threaded Check Valves for Harsh Chemicals

Threaded Check Valves for Harsh Chemicals

Ultra-Chemical-Resistant Threaded Check Valves

Check Valves with Push-to-Connect Fittings for Harsh Chemicals

Vacuum-Breaking Valves for Chemicals

Welding Gas Check Valves for Regulators

Welding Gas Check Valves for Torches

Welding Gas Flashback Arresters for Regulators

Welding Gas Flashback Arresters for Torches