We just had to have a pilot operated check valve replaced on our back hoe.
On the back hoe we have singles and doubles. The single holds the bucket in
position until the pump pressure tells the valve to open and move the
bucket. The double is in the steering circuit to prevent the steering wheel
from jumping when the front wheels hit an obstruction.
What it does is act like a regular check valve until it sees pressure on the
pilot port and then turns it into a two way valve. On a double the pressure
lines from opposite sides are piped to the pilot ports so that when the
starboard valve sees pressure from the port steering side it opens and lets
the hydraulic fluid flow back to the pump allowing normal steering. If the
rudder is jammed over to port pressure on the starboard line to the rudder
will be high and pressure from the port pump to its check valve will be low
so the starboard check valve closes and prevents back flow to the pump.
The 211-1009 is just an open center control and does not come with check
valves. Open center controls direct the output of a constant pressure pump
and high pressure back flow can not only jerk the wheel but also damage the
pump leaving you with no steering at all. Normally you would probably use a
relief manifold that has the check valves built in. The relief manifold
bleeds the excess pressure back to the pump reservoir but that would let the
rudder move a little on its own and I am not sure you want that to happen at
120 MPH.
Eaton and Parker both make pilot operated check valves. You might check
their catalogs for a double. Worse case you could get two singles and tap
off the ports of the 1009 to cross feed the pilots on each valve.
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at:
http://www.rutuonline.com
Shameless Commercial Division:
http://www.spade-anchor-us.com
"Larry" wrote in message
news:s24ng.2278$Wh.192@trnddc04...
Hello,
I've asked 'the experts' but they must have thought I was asking for
'trade
secrets' and subsequently offered no help.
Here's my problem; I'm installing an Arneson ASD8 Surface Drive in my 30
foot Cobra Terminator race boat and understand I should use a Double
Piloted
Check Valve (DPCV) between the steering cylinder and the helm to eliminate
feedback into the wheel as discussed online at:
http://www.h-ri.com/Product/Steering..._sys_DPCV.html
I'll be using a single station, power hydraulic steering system with a
char-lynn 211-1009-002 helm (recommended for use with the ASD8). I've
been
unable to contact anyone at www.h-ri.com for further details and my
internet
searches (using various related phrases in Google) have been fruitless.
Does anyone here have experience with a Double Piloted Check Valve
installed
in their hydraulic steering system? What manufacturer and part number DPCV
should I be looking at?
You can follow the progress (or lack of progress) on my turbine powered
boat
project online at: www.TurbineFun.com
Thanks (in advance) for your assistance!
Larry