High accuracy flow divider valve
Flow dividers are sliding-spool, pressure-compensated devices used to split oil flow to two different branches of a circuit in a designated ratio. These valves are suitable for applications that use the following: unidirectional hydraulic motors, hydraulic cylinders where flow division in one direction only is required, and multiple circuits that are serviced from one pump supply.
- All flow divider and divider/combiner cartridges are physically interchangeable (i.e. same flow path, same cavity for a given frame size).
- Operating characteristics cause the leg of the circuit with the greatest load to receive the higher percentage of flow in dividing mode. If a rigid mechanism is used to tie actuators together, the lead actuator may pull the lagging actuator and cause it to cavitate.
- In applications involving rigid mechanisms between multiple actuators, operating inaccuracy will cause the eventual lock-up of the system. If the mechanical structure is not designed to allow for the operating inaccuracy inherent in the valve, damage may occur.
- In motor circuits, rigid frames or mechanisms that tie motors together, and/or complete mechanical synchronized motion of the output shaft of the motors, either by wheels to the pavement or sprockets to conveyors, will contribute to cavitation, lock-up and/or pressure intensification.
- Variations in speed and lock-up can be attributed to differences in motor displacement, motor leakage, wheel diameter variance and friction of wheels on the driving surface.
- This valve is a divider only; any attempt to flow backwards through the valve is not advised.
- Below the minimum flow rating there is not enough flow for the valve to modulate. It is effectively a tee. If flow starts at zero and rises, there will be no dividing control until the flow reaches the minimum rating.
- 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||6 - 30 gpm23 - 120 L/min.|
|Pressure Drop at Minimum Rated Input Flow||30 psi2 bar|
|Pressure Drop at Maximum Rated Input Flow||250 psi18 bar|
|Valve Hex Size||1 5/8 in.41,3 mm|
|Valve Installation Torque||350 - 375 lbf ft474 - 508 Nm|
|Model Weight||2.80 lb1,30 kg|
|Seal kit - Cartridge||Buna: 990034007|
|Seal kit - Cartridge||Polyurethane: 990034002|
|Seal kit - Cartridge||Viton: 990034006|
No. Almost all of the error percentage we publish is due to flow forces. Even with a mechanically perfect valve you would see most of the variation.
The divider/combiner is an FSDH XAN. Input flow is 15 gpm (57 L/min.). This example depicts orifices that slip about 3 gpm (12 L/min.) at 3000 psi (210 bar) pressure differential between legs. The slip conditions between the 2 examples are the same...please be assured of this. Each orifice on the right is twice the area of the orifice on the left.
The pressure drop through the left example is 200 psi (14 bar), the drop through the right example is 130 psi (9 bar).
Absolutely not. The bell curve does not apply here. In the dividing mode the high pressure leg gets the higher flow and in the combining mode the high pressure leg is the lower flow......every time. The inaccuracies are always there and they accumulate. The high pressure leg goes up farther and comes down less, every time.
With a typical steered axle application the outside wheels go 15% to 20% farther than the inside wheels. As to how big your slip orifices need to be, there is no correct answer and you are the one that needs to make the compromise. If they are too big you will not have the traction you need at low speeds and if they are too small you will not be able to turn at higher speeds.
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
It is a static error correction feature. When any one of the 3 ports of a divider/combiner with the synchronizing feature is blocked, flow is possible between the other 2 ports. This "synchronizing" flow is called out in the performance chart and is pressure compensated.
When the leading actuator comes to a stop, the other actuator can catch up at a rate determined by the "synchronizing" flow.
When the actuators are stopped mid-stroke (port 3 blocked), oil can flow from the high pressure leg to the low pressure leg at a rate determined by the "synchronizing" flow.
The "synchronizing" flow does not exist until one port is blocked.
The "synchronizing" feature is most effective on applications where the actuators bottom out at at least one end of their strokes.
No. Synchronizing two cylinders hydraulically is a real problem which has no solution. Our valves with the synchronizing feature don't synchronize — they provide an error correction at each end of the stroke when the leading cylinder bottoms out. Another means of error correction is cross-port reliefs.
We test every cartridge in 16 modes. High pressure, low pressure, high flow, low flow, divide, and combine.....both legs. What you are probably seeing is the error that occurs as the flow is ramping up to the minimum rated flow. Below the minimum rated flow the valve does not see enough flow to operate correctly.
We eliminated the hooks. We have a 1 piece spool.
It is another name for what we call a priority flow control. We don't call it a divider because it doesn't start dividing until there is enough flow to satisfy the priority flow.
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