3-way, fully adjustable, bypass/restrictive, priority flow control valve

Capacity: 30 gpm120 L/min. | Cavity: T-17A
FREL : 3-way, fully adjustable, bypass/restrictive, priority flow control valve
Technical Features [ + ]

This valve is a fully adjustable, bypass/restrictive, priority flow control valve. The valve takes an input flow at port 1 and uses it to satisfy the priority flow at port 3. If the input flow exceeds the priority requirement, the excess is bypassed out port 2.

The valve pressure compensates the priority flow for precise flow regulation for applications where there may be wide pressure fluctuations. Port 2 may also be completely blocked so that the valve can be used as a 2-way, pressure compensated flow control from 1 to 3.

  • Both priority and bypass flow are usable up to the system operating pressure.
  • Priority remains relatively constant regardless of variation in input flow.
  • Bypass flow is not available until priority flow requirements are satisfied.
  • Pressure at the bypass port (port 2) may exceed pressure at the priority port (port 3).
  • In applications where the priority flow will be completely blocked, bypass pressure drop will increase over time unless a leak path is provided for the priority flow.
  • Designed using CFD fluid simulation for optimized geometries.
  • Exceeds NFPA test standard T2.6.1 R2014 for fatigue and burst pressure ratings.
  • 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-17A
Series 3
Capacity 30 gpm120 L/min.
Maximum Operating Pressure 5000 psi350 bar
Viscosity Range 35 - 2000 SUS2,8 - 380 cSt
Adjustment - No. of CCW Turns from Fully Closed to Fully Open 55
Typical Valve Leakage at 110 SUS (24 cSt) from port 1 to port 3 at 5000 psi (350 bar) 75 mL/min.75 mL/min.
Rated Maximum Priority 17.6 gpm66,5 L/min.
Response Time - Typical 50 ms50 ms
Valve Hex Size 1 1/4 in.31,8 mm
Valve Installation Torque 150 - 160 lbf ft203 - 217 Nm
Model Weight 1.20 lb0,55 kg
Performance Curves [ + ]
FAQs [ + ]

We claim +/- 10%. We set to +/- 5% in production testing to allow for differences in customers' conditions. If you want accuracy, stay in the bottom 2/3rds of the range. Our 12 gpm (45 L/min.) flow controls are quite flat at 9 gpm (34 L/min.) and dead flat below 6 gpm (23 L/min.), until you get to the bottom of the range. Below about .25 gpm (1 L/min.), spool leakage and orifice conditions start to limit accuracy.

I am afraid not. Unless you are overflowing your current valve and correctly size ours, you are not likely to notice any improvement. Priority flow controls are not efficient devices. They are an easy way to get more than 1 source of oil from 1 pump but they can generate a lot of heat. Try to size your actuators so the pressures are similar on both the priority and the bypass circuits. If you can't do that, try to have the lower flow leg be the lower pressure. The pump pressure is determined by whichever leg is higher and if there is flow that is taking a pressure drop that is not doing work it is creating heat.

All flow is blocked, hence the term priority. The priority flow has to be satisfied.

The valve acts as a 2 port restrictive flow control.

The spring force in our flow controls equates to about 100 psi (7 bar). This is high enough to give the valves acceptable capacity (not really) and not too high for proper circuit operation. 100 psi (7 bar) is the spring force; at the upper end of the flow control's range, the drop through the valve will be as high as 250 psi (17 bar) before it starts modulating.

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

In a meter-in flow control circuit if the pump is set at 3000 psi and the load is 2000 psi the drop through the flow control is 1000 psi. In a meter-out circuit with the load at 2000 psi the drop through the flow control is 2000 psi.

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 [ + ]