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TA797 Ultra High Flow Two-Way Relief Valve


The TA797 high-flow two-way relief valve is designed to offer similar pressure direction flow characteristics as AGMs TA796 One-way relief valve, but also provide vacuum direction flow within the same 4-inch diameter valve housing. It achieves high flow in the pressure direction with its unique, patented design that utilizes powerful rare earth magnets instead of the compression springs found on a conventional breather valve. The magnets allow the valve to open quickly and completely in the pressure direction once the initial opening resistance is overcome. For the vacuum direction, while providing higher flow than most other breather valves, it is controlled by the conventional, compression spring and poppet mechanism, so a gradual increase in vacuum direction flow as pressure increases should be expected.

This valve is commonly used for a combination of rapid decompression or explosive decompression events, where it is necessary to vent a container or enclosure quickly to prevent dangerous pressure buildups, as well as to provide day to day breathing as the container or enclosure requires. While decompression events are typically due to a sudden loss of pressure inside an airplane fuselage, the TA797 can be used in any application where high volume air venting is required.

The TA797 valve is hardier than most other products that are meant to provide protection during decompression events. For example, a blow-out membrane can be damaged by impact from material handling equipment such as a forklift, by accidental contact with protuberances on other containers, or by incidental pressure events. Additionally, blow-out membranes are not reusable. By contrast, the sturdy aluminum construction of the TA797 stands up to rough handling, and the valve will reseal automatically after relieving excess pressure spikes providing virtually unlimited reuse.

The following table shows a few of the currently available TA797 part numbers and their corresponding settings. Any combination of these pressure and vacuum settings can be achieved, and other potential settings may be possible. Contact AGM's Engineering department for assistance with verifying whether your desired settings are achievable or if other information is needed.

Part Number
Cracking Pressure Range (PSID)
Minumum "P" Flow Rate (SCFM by PSID)
Cracking Pressure Range (PSID)
Minumum "V" Flow Rate (SCFM by PSID)
0.25 - 0.50
525 by 1.50
0.25 - 0.50
160 by 1.75
0.50 - 0.80
525 by 1.50
0.50 - 0.80
160 by 2.00
0.75 - 1.00
525 by 1.50
0.75 - 1.00
160 by 2.25
1.00 - 1.25
525 by 1.50
1.00 - 1.25
160 by 2.50
1.50 - 1.70
525 by 2.00
1.50 - 1.70
160 by 3.50

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MaterialsHousing, Cover, Vacuum Float, Vacuum Seat, Washer & Nut - Aluminum Alloy • Cover Screws - Stainless Steel
Materials (Cont.)Pressure Float & Magnet Support - Glass Filled Polycarbonate • Magnets - Nickel Plated Neodymium Iron Boron
Materials (Cont.)Vacuum Spring – Stainless Steel • Gasket and Internal Seals - Silicone
Mounting Hole Diameter4.050 ± .04 (50.8 ± 1 mm)
Maximum Wall Thickness0.50 (19 mm)
Torque Value for Nut150 in-lbs (17 N•m)
Weight1.565 lbs. (710 grams)
Cracking Ranges Available (psid)0.1 - 1.5

Housing and nut have hook spanner notches.
Use a 4.5-inch hook spanner wrench for the nut and a 5.25-inch hook spanner wrench for the housing.

TA797 Drawing

TA797 Ultra High Flow Two-Way Relief Valve drawing

Additional information

Patent Number



Housing, Cover, Vacuum Float, Vacuum Seat, Washer & Nut-Aluminum Alloy, Cover Screws-Stainless Steel, Float & Magnet Support-Glass Filled Polycarbonate, Magnets-Nickel Plated Neodymium Iron Boron, Vacuum Spring-Stainless Steel, Gasket & Internal Seals-Silicone



Mounting Hole Diameter

4.050 ± .04 (103 ± 1 mm)

Maximum Wall Thickness

0.50 in. (13 mm)

Torque Valve for Nut

150 in-lbs (17 N•m)


1.565 lbs. (710 grams)

Cracking Ranges Available

0.1-1.5 psid

Operating Temperature

-80°F to +160°F (-62°C to +71°C)

AGM Container Controls, Inc.
3526 E. Fort Lowell Rd.
Tucson, AZ 85716

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