[AT] Power Steering

Dennis Johnson moscowengnr at yahoo.com
Thu Feb 18 16:03:42 PST 2010


One other source for Char Lynn units is some oild oilfield equipment. We have used them for years to actuate some cylinders. We have a small steering wheel type on them, and it outputs to a cylinder to control a valve position or a slide valve. They are also common on some other small industrial equipment steering systems.
There are 2 different type of Char Lynn Units. 
One type is a closed center that only flows oil when you turn the handle. It does not normally flow any oil between the pressure and the tank port. These types of pumps are designed to "tee" into a pressure circuit and not flow any oil though them when the handle is not turned. If you put one of these onto a power steering type of circuit, you end up dumping oil over a releif valve, making heat, using excess energy, and wearing out the releif valve.
The other type is an open center type that normally flows oil between the pressure and tanak port, and diverts oil to the A or B port when the handle is turned. These units are made to work with a small power steering type pump that will continuously flow at low pressure until you turn the handle.
I think that I have a Char Lynn unit somewhere, but not sure that I am ready to part with it. I had thought about using it to steer an articulated tractor I want to build someday.
Regards,
Dennis
 


      



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