3-way, direct-acting, fixed setting, directional valve with drain to port 4 (1 blocked, 2 to 3 open)

Capacity: 7 gpm28 L/min. | Cavity: T-21A
DRBOX : 3-way, direct-acting, fixed setting, directional valve with drain to port 4 (1 blocked, 2 to 3 open)
Technical Features [ + ]

Direct-acting, 3-way directional cartridges (1 blocked, 2 to 3 open) are switching devices typically used in moderate flow circuits. They can be used by themselves or to actuate larger pilot-operated directional cartridges or logic cartridges. The valve shifts when the pressure differential between port 1 and port 4 exceeds the setting.

  • Port 3 can be used as a work port.
  • The flow path between port 2 and port 3 is bidirectional.
  • Because of their direct-acting design, these cartridges feature low internal leakage and low pilot flow consumption.
  • Direct-acting and pilot-operated versions of these valves are interchangeable. They fit the same cavities and have the same flow paths.
  • Pressure at port 4 is directly additive to the setting of the valve.
  • This valve is not bistable; it is capable of modulating between the two positions shown.
  • The flow path between port 1 and port 2 is bidirectional.
  • Maximum pressure at port 3 should be limited to 3000 psi (210 bar). This is due to fatigue strength limits not hydraulic operating limits.
  • 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-21A
Series 1
Capacity 7 gpm28 L/min.
Factory Pressure Settings Established at 4 gpm15 L/min.
Maximum Operating Pressure 5000 psi350 bar
Maximum Valve Leakage at 110 SUS (24 cSt) 2 in³/min.30 cc/min.
Valve Hex Size 7/8 in.22,2 mm
Valve Installation Torque 30 - 35 lbf ft41 - 47 Nm
Model Weight .55 lb0,25 kg
Seal kit - Cartridge Buna: 990021007
Seal kit - Cartridge Polyurethane: 990021002
Seal kit - Cartridge Viton: 990021006
Performance Curves [ + ]
FAQs [ + ]

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.

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

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.

In many circuits the directional cartridge is set to shift at a low pressure no matter how high the pilot pressure goes. If you use a DP__ , the pilot flow increases to significant amounts. A DR__ however will only consume a small amount of flow. A DP__ is useful when you want to block or open the pilot flow to shift the valve.

DP**s and DR**s are from the reducer/reliever family and are very capable of modulating. They are not bistable.

Additional Resources [ + ]