Description
TA770-R Breather Valve
High-Capacity Two-Way Pressure and Vacuum Relief
Conforms to MIL-DTL-27166, SAE AS27166 & U.S. Navy Drawing 6212863
The TA770-R breather valve from Arcadia Desiccant provides independent pressure and vacuum relief settings, offering a high flow rate of 10.0 to 25.0 SCFM at 1.5 psi above the valve setting. It is well suited to large enclosures and transit containers up to 208 cubic feet in volume. Standard reseal pressure settings range from 0.5 psid to 5.0 psid, with higher flow rates at lower settings.
This valve is tamper-resistant, maintenance-free, and manufactured from corrosion-resistant materials. The internal seal is made from silicone rubber, and the Teflon-coated spherical valve seat ensures smooth actuation, even after extended storage.
A recessed manual release push button is integrated into the design to allow pressure equalisation for easy opening. The recessed design protects the button from accidental activation, and a light-duty spring separates the button from the vacuum stem, adding an additional layer of protection against unintentional actuation.
Each TA770-R valve is supplied with a gasket, washer, and hex nut for mounting. Options for RFI/EMI shielding and a rear-mounted high-flow filter (with or without shielding) are available.
The TA770’s specially designed cover and dust baffle offer outstanding protection from dust and sand ingress. The design also provides excellent resistance to high-pressure hose-down conditions. When compared with screened valves (such as Arcadia Desiccant’s TA238) and competitor models, the TA770 significantly reduces water ingress under high-pressure water streams.
The TA770 has been tested to NEMA 250 Section 5.7 for high-pressure hose-down protection.
Cracking vs Reseal Valves:
Cracking and reseal valves are structurally identical; the difference lies in their performance specification:
-
Reseal valves conform to MIL-DTL-27166 and SAE AS27166 reseal/cracking pressure criteria.
-
Cracking valves are defined by nominal actuation pressures (e.g., 0.25, 0.5, 1.0, 2.0 psi, etc.).
Both types are rated for cracking and reseal performance. Simply choose the valve with the settings that meet your application’s needs, regardless of whether it is listed as a reseal or cracking variant.
Sizing Guidance:
According to SAE AS27166, a breather valve should provide a flow rate of at least 12% of the container volume per minute, at a pressure below the container’s pressure rating.
Example: A 10 cubic foot container with a 2 psi pressure rating requires a valve that flows 1.2 SCFM at 2 psid or less. A valve with a crack point of 2 psi may appear suitable, but flow at the crack point is extremely low (approx. 1 cc/min), which would likely be insufficient.
Flow rate vs pressure curves are available for select valves. Please contact Arcadia Desiccant’s engineering department for additional technical guidance.
Materials and Finish:
-
Housing, Hex Nut & Washer: Aluminium
-
Gasket: Silicone rubber (A-A-59588 Class II Grade 60)
-
Finish: Anodised housing, nut, and washer
Mounting Specifications:
-
Mounting Hardware: Supplied with gasket, washer, and hex nut
-
Mounting Hole Diameter: 2.050 ± 0.020 in. (52 ± 0.50 mm)
-
Wall Thickness Range: 0.001 in. (0.03 mm) minimum to 0.75 in. (19 mm) maximum
-
Installation Torque: 80–90 in-lbs (9.0–10.0 N·m)
-
Weight: 0.40 lbs (181 grams)
For threaded boss installations: Use 2.00-18 UNS-2B; requires 2.050 ± 0.020 in. (52 ± 0.50 mm) counterbore diameter with minimum 0.085 in. (2 mm) depth for thread relief.
For IP/NEMA rating guidance or application-specific recommendations, please contact Arcadia Desiccant’s engineering team.
