Most skid steer attachments on the market are designed with a standard flow hydraulic system. However, when an attachment needs a large amount of hydraulic power, manufacturers will design them for use with high flow skid steers.
Here are some standard minicart accessories that often require high flow:
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Drum crushers
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Oscillating arm stump grinders
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Severe duty cold scrubbers
Let’s dig a little deeper into this.
What do we mean by “high flow miniature fittings”
High flow miniature fittings are hydraulically actuated fittings that require a higher fluid flow than the typical standard flow fitting. A high flow skid steer attachment must be combined with a skid steer with high flow hydraulics.
High flow hydraulics are an option offered by many modern skid steer manufacturers. A typical high-flow skid steer will be able to produce 26 to 40 gallons per minute of flow, but this will vary by make and model.
Why do some minicart attachments require high flow hydraulics?
Some miniature attachments have a higher demand for hydraulic power than others. Take, for example, a cold milling machine that mills concrete versus a brush cutter that cuts grass. The cold milling machine will need more power than the brush cutter.
This additional power will come from higher hydraulic flow.
Higher hydraulic flow increases hydraulic power when the pressure remains constant. The formula to represent it is:
Gallons per minute (GPM) times hydraulic pressure in pounds per square inch (PSI) divided by 1,714 equals hydraulic power.
For example, a standard flow skid steer with 17 GPM of hydraulic flow at 3,500 PSI will produce about 34 hp, while a high flow skid steer of 40 GPM at the same 3,500 PSI will produce over 80 hp of hydraulic power.
Power is the yardstick for measuring how much “work” is being done in a given amount of time. When you need a high-powered attachment, you increase the hydraulic flow to the engine, and that’s how you end up with a high-flow attachment!
Here are some popular attachments that require high flow hydraulics
Blue Diamond Drum Crusher
As with most drum crusher attachments on the market, Blue Diamond’s drum crusher requires your miniature to have a high-flow hydraulic system that can handle 35 to 52 gallons per minute.
The drum shredder’s hydraulic motor must keep the drum spinning at speeds up to 3,600 rpm while consistently meeting the resistance of trees and other debris, which require a lot of horsepower.
If we ran this drum crusher with a high flow Kubota SVL97 at 40 GPM and 3500 PSI, we would produce approximately 81.6 HP, which would be more than enough to run the crusher.
When we look a little closer at the drum crusher, we also notice that the hydraulic flow relief valve will open at 50 GPM, with a maximum of 6,000 PSI. Crunching these numbers would suggest that the crusher may be capable of running close to 175 HP! (Of course, we always want to carefully adhere to the limits set by the manufacturer to avoid injury and damage).
Blue Diamond Swing Arm Stump Grinders
Of the three models of swing arm stump grinder attachments that Blue Diamond offers, all three require a high-flow hydraulic system.
Swing arm stump grinder hydraulic flow rates reflect the larger displacement hydraulic motors installed in them. Depending on the swing arm stump grinder model, it will have a 130cc, 150cc or 170cc hydraulic motor.
While the large hydraulic motor turns the flywheel of the stump grinders through a hard stump, there must be enough hydraulic flow left to operate four large hydraulic cylinders that control the swing arm.
The first two hydraulic cylinders are 2.5″ by 6″ and rotate the “swing arm” of the stump grinder. The third cylinder measures 4.5″ by 8″ and raises and lowers the swing arm. The last 2.5″ by 12″ cylinder extends the swingarm. Together, these cylinders require a large amount of hydraulic flow.
The smallest swing arm stump grinder model offered by Blue Diamond is the 29-33 GPM model. It has a 60cc radial piston hydraulic motor, runs from 3,000 to 4,061 PSI and is advertised to produce 55 to 77 hydraulic horsepower.
You can plug these numbers into our formula to check Blue Diamond’s power ratings. On the low end, at 29 GPM and 3,000 PSI, the stump grinder will have 51 HP. At the high end, with 33 GPM and 4,061 PSI, the stump grinder will have 78 HP.
Blue Diamond Heavy Duty Cold Planer
Milling concrete and asphalt up to 8″ and not having the cutting drum overcome with resistance requires a lot of horsepower. The severe duty cold milling machine even uses a planetary gearbox to help produce more torque.
Blue Diamond’s Severe Duty Cold Planer models require a hydraulic flow rate of 30 to 42 GPM with a pressure range of 2,000 to 5,000 PSI. As you know, this will give us between 35 and 120 hydraulic horsepower.
In addition, the cold milling machine will have two hydraulic cylinders to adjust the depth of the milling machine and one hydraulic cylinder to control the inclination of the milling machine.
conclusion
Understanding flow and pressure isn’t necessary to own and operate a skid steer, but it can help you choose the right attachments for a job.
If you have any more questions about the High Flow Thumbnail Accessories, you can contact me directly via the hyperlink provided.
