FMDF | Cartridges » Flow Control » Flow Control

This valve is a 3-way, meter-in, electro-proportional throttle. The flow path, unenergized, has the supply blocked at port 1 and port 2 is drained to tank at port 3. Energizing the coil generates a closing force on the spool, creating a metering orifice in the 1 to 2 direction that is proportional to the coil command current. The valve self-compensates in the 1-to-2 direction and with the addition of an external compensator will provide pressure compensated flow control.

Flow in the 2-to-3 direction is not proportional and is limited in the interest of increased resolution and capacity. Flow capacity in the 2-to-3 direction is about 1.5 gpm (6 L/min). This valve is meant to be used in a circuit that has a separate passage to tank such as a cushion lock circuit. Two FMDFs in conjunction with a cushion lock circuit create a meter-in/meter-out 3-position 4-way.

Note: Flow in the 2 to 3 direction is limited to about 1.5 gpm (5 L/pm).
The transition between positions is closed.
Using 2 3-ways to create a 4-way allows one to choose existing flow ranges instead of cutting a special spool.
These valves may be pressure compensated by an external, modulating, logic element. Use LR_C-XHN for a bypass circuit or LP_C-XHN for a restrictive circuit.
The valve provides a degree of self-compensation and may be used as a flow control. To increase the accuracy of flow control, an external, modulating, logic element can be used to maintain a constant flow over a wider range of flows and pressures. See performance curves for additional information.
For optimum performance, an amplifier with current feedback and adjustable dither (100 - 250 Hz) should be used.
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.

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Note: Data may vary by configuration. See CONFIGURATION section.

Cavity	T-11A
Series	1
Capacity	9 gpm34 L/min.
Maximum Operating Pressure	5000 psi350 bar
Maximum Valve Leakage at 110 SUS (24 cSt)	2 in³/min.@1000 psi30 cc/min.@70 bar
Manual Override Force Requirement	5 lbs/1000 psi @ Port 133 N/100 bar @ Port 1
Manual Override Stroke	.10 in.2,5 mm
Solenoid Tube Diameter	.63 in.16 mm
Valve Hex Size	7/8 in.22,2 mm
Valve Installation Torque	30 - 35 lbf ft41 - 47 Nm

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Note: Data may vary by configuration. See CONFIGURATION section.

Hysteresis (with dither)	<4%<4%
Hysteresis with DC input	<8%<8%
Linearity (with dither)	<2%<2%
Repeatability (with dither)	<2%<2%
Recommended dither frequency	140 Hz140 Hz

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Performance Curve for FMDF: Electro-proportional 3-way flow control valve, meter in (740 Series)

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What happens if I block the control flow (priority) port?

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

What happens if I block the bypass port on a priority flow control?

The valve acts as a 2 port restrictive flow control.

What is the compensating pressure of Sun's flow controls?

The spring force in our flow controls equates to about 100 psi (7 bar). This is high enough to give the valves acceptable capacity 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.

How big is a drop of hydraulic oil?

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

What is the pressure drop through a flow control?

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.

How accurate are Sun's flow controls?

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 have a heat problem, will Sun's priority flow control help?

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.

What parts of the Sun cartridge valve are field serviceable?

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.

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Please verify cartridge clearance requirements when choosing a Sun manifold. Different valve controls and coils require different clearances.
An additional 2.00 inches (50,8 mm) beyond the valve extension is needed for coil installation and removal.

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Highlights