Air-controlled, direct-acting relief valve - pilot capacity

Capacity: .5 gpm2 L/min. | Cavity: T-3A
RBAB : Air-controlled, direct-acting relief valve - pilot capacity
Technical Features [ + ]

Air-controlled, pilot relief cartridges are used to remotely control the pressure setting of other pilot operated valves. Because capacity is limited to pilot flow, these valves should be used with valves with compatable pilot flows. They use compressed air over a diaphragm instead of an adjustable spring to control pressure setting, the air signal is supplied through a port in the hex-end of the cartridge.

  • Maximum air pressure should not exceed 150 psi (10 bar).
  • Pressure settings are insensitive to back pressure at the tank port (port 2). Back pressure should not exceed 1000 psi (70 bar).
  • Capable of providing explosion proof remote control of the pressure setting, the hydraulic setting is directly porportional to the air setting at a ratio of 20:1 (hydraulic:air).
  • Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.
Technical Data [ + ]
Note: Data may vary by configuration. See CONFIGURATION section.
Cavity T-3A
Series 2
Capacity .5 gpm2 L/min.
Maximum Operating Pressure 2000 psi140 bar
Pilot Ratio 20:120:1
Maximum Valve Leakage at 110 SUS (24 cSt) 5 drops/min.0,3 cc/min.
Response Time - Typical 2 ms2 ms
Valve Hex Size 1 1/8 in.28,6 mm
Valve Installation Torque 45 - 50 lbf ft61 - 68 Nm
Model Weight .50 lb0,25 kg
Seal kit - Cartridge Buna: 990203007
Seal kit - Cartridge Viton: 990203006
Performance Curves [ + ]
FAQs [ + ]

Pressure setting tolerances are listed in our Performance Data page. A link to this page can also be found in the Additional Resources tab of the applicable product page.

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

Maybe not. We build in a good amount of overlap in the kick-down reliefs to prevent false tripping. This means they are not as fast as our standard pilot-operated reliefs. A direct-acting relief valve set just above the kick-down relief valve would be good insurance.

Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.

One graphic example is on a portable grain auger for silos. When the farmer gets caught in the auger the kick-down relief trips and allows him to escape.

Only external seals are serviceable.  Sun offers replacement seal kits for all cartridge models. The applicable kit part number can be found in the product page's Technical Data table or by using our Cartridge Seal Kit search function located under Accessories. Please note: Converting the external seals from one material to another does not ensure fluid compatibility with that material due to the existence of internal seals within the cartridge.
Additional Resources [ + ]