David McDonald on sun 25 jun 00
In response to your (David Hendley's) questions regarding my hydraulic
extruder;
Cylinder is an old Boeing Aircraft ramp cylinder, from an aircraft
salvage yard. Fill in the blank with whatever you can find that works, &
is cheap. I paid $45 for mine. It's double action, meaning that it
extends, and retracts. A hose fits to each end of the cylinder barrel.
Cylinder rod extends 16 to 18 inches, and is about 1" diameter.
The pump is a 1/2 GPM hydraulic gear pump, attached to a 1/2 horsepower
electric motor. A 2 gallon hyraulic fluid reservoir sits next to the
motor/pump.
I've mounted a four way control valve near the floor, which I can push
down on to extend, and lift up on to retract, with my foot, leaving both
hands free to work with the clay coming out of the extruder die. Control
valve is called "4 way", but only does two things that I can see; send
the fluid pressure going to the top of the cylinder to extend the
cylinder rod, or send the fluid pressure to the bottom of the cylinder to
retract the cylinder rod.
Onto the end of the cylinder rod, I've attached a plunger plate, which
is 1/2" plywood, backed up by 1/4" steel. The wood was easier to cut to
fit the inside of the clay barrel. The steel back up plate is cut a
little smaller, and keeps the wood from getting busted up from the
extreme pressure.
The clay barrel is 6 1/2"square X 1/8" thick extruded steel tubing,
which accepts a standard bag of pugged clay from the supplier. This whole
assembly is mounted to a 6" wide by 4' length of channel iron, which is
mounted to the wall. The top of the hydraulic cylinder pivots, so that
the cylinder can swing out of the way for loading clay into the barrel.
The rate of speed of the cylinder as it's extending is fairly slow.
Maybe 1/2 inch per second at full pressure. I'm glad for this, as it
makes it much "safer". One can only imagine the damage to fingers and
hands from such a machine, if attention is not well paid. So since the
rate of cylinder extension is 1/2 inch per second, obviously the clay
will be coming out of the die at a much faster rate. The amount of
pressure I put on the foot valve allows me a very fine degree of control
over the extruding process. Also, there is no "lag time" between letting
go of the valve, and the plunger stopping. It is immediate.
I recall the whole thing costing me around $450 to make, since a friend
and I welded and put it together. Am I happy with it? YOU BET! Kind of
like a hot rod extruder! If anyone's interested in seeing a picture of
it, I'll try to post one on the web. I know it must be hard to visualize
it as I describe.
Hope this answers your questions David. Go for it! David McDonald
On Sun, 25 Jun 2000 10:56:14 -0500 "David Hendley"
writes:
> Hey David, I'm considering building a hydraulic extruder
> and would be interested in hearing how you like working
> with yours. I'm sending this to Clayart, since there may
> be some others interested.
>
> A few questions, if you don't mind:
>
> Do you use a hand pump, or motorized? I'm thinking a
> hand pump might be too slow, but a motor might be
> too fast and hard to control.
>
> Do you have a two-way cylinder that will retract as
> well as extrude? If not, how do you remove the
> plunger after extruding?
>
> Is there much 'lag time'; does clay continue to come
> out after you have stopped the cylinder?
>
> I agree with your advice to Anji about extruder installation;
> attach the post to the floor and the ceiling and it will be
> plenty strong. No need for concrete really; concrete anchors
> on the floor and bolts to the ceiling joists are adequate.
>
> --
> David Hendley
> Maydelle, Texas
> hendley@tyler.net
> http://www.farmpots.com/
________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk! For your FREE software, visit:
http://dl.www.juno.com/get/tagj.
| |
|
