Saturday, October 13, 2012

CEB Hydraulics

hydraulic rover and CEB machine
The CEB presses require 2200 psi of hydraulic pressure to operate. I had originally thought I would use a large tractor and its established hydraulics. I could unhook the kwik-couple units from the seat and then free the tractor for hauling bricks and re-loading soil to the hopper.

Well, experience taught me quickly that those extra steps were tiring, so we tried another option: retrofitting an old mower. I had an 26-HP Briggs Stratton mower on a frame and so we converted that to produce all the hydraulic power we need and more. We can still use the larger tractor should we need to.
hydraulic pump with industry coupler
As you can see from the photo of the hydraulic pump underneath the mower, we removed the blade deck and installed this industry standard coupler to run the 16-gpm pump directly from the engine shaft.
hydraulic controls and pressure gauge
oil reservoir filter and cooler
The fat hose out the back is a return hose and it is very low pressure. The high pressure lines from the pump come out the front to a junction where we have a cut off valve to circulate the oil without going to the press while starting the engine. Then the valve is closed and oil under 2200 psi flows to the solenoids to operate them electronically by the controller.

Should the pressure exceed its limit of 2200 psi, the black poppet valve has been set to release the pressure and return oil to the reservoir in the rear of the machine. The main cylinder also has its own dedicated pressure relief switch and will send the cylinder on to the next step if it doesn’t reach the cut-off pin exactly when it reaches its maximum pressure. That way it won’t just sit there pushing if it should get a little too much dirt in one load and can’t quite compact it enough to reach the sensor.

You can see the large steel sensors and the bolt heads (buttons) that they read as the cylinders slide by.

Normal flow through the lines and the solenoids generates extreme heat and so we added a cooler that maintains oil temperatures well below 150oF. The long lines to the machine allow the noisy mower engine to not seem so loud when its close. The lines are also cooled this way. I use a laser remote thermometer to monitor all lines and valves and engines to maintain safe temperatures and keep the working environment pleasant and safe.

The nice thing is that all of this equipment is not only custom made for this machine but it is extremely high quality and industrial lstrength materials. The next machines will take must less time and cost much less to make.
Bell propriety components- proximity sensor and pins


Zach Dwiel said...

Two questions:

1) Those look like induction sensors you've used instead of magnetic sensors. What kind of circuit is used to interface those to the microcontroller?

2) What kind of pressure gauge are you using to detect maximum pressure on the primary cylinder? The only digital gauges I can find are super expensive.


Pittsburgh Tool Library said...
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