FMDAXBV924 - Electro-proportional 3-way flow control valve, meter in
Part Number: FMDAXBV924
Manufacturer: Sun Hydraulics
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 FMDA's 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.
- All ports will accept 5000 psi (350 bar).
- On models equipped with the D or L control, the detent mechanism in the manual override is meant for temporary actuation. The D, E, L and T manual control assemblies have a mechanical life expectancy of approximately 7,000 cycles.
- The momentary/twist override option "E" allows the operator to shift the valve by twisting the manual override clockwise 90 degrees.
- Coils are interchangeable with Sun's other full flow, solenoid-operated valves and can be mounted on the tube in either direction.
- For optimum performance, an amplifier with current sensing and adjustable dither should be used. Dither should be adjustable between 100 - 250 Hz.
- 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.
|Capacity||9 gpm34 L/min.|
|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||.75 in.19 mm|
|Valve Hex Size||7/8 in.22,2 mm|
|Valve Installation Torque||30 - 35 lbf ft41 - 47 Nm|
|Model Weight (with coil)||1.10 lb0,50 kg|
|Seal kit - Cartridge||Viton: 990-411-006|
|Seal and nut kit - Coil||Viton: 990-770-006Viton: 990-770-006|
|What happens if I block the bypass port on a priority flow control?||The valve acts as a 2 port restrictive flow control.|
|How big is a drop of hydraulic oil?||There are exactly 250 Sun drops in a cubic inch or 15 in a cc.|
|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 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 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 (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.|
|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.|