Relief valve

[seacap04]

I need to eat crow. Awhile back I converted an old Fisher plow to QA. I extended rear remotes to front of FEL and used QD's for connecting to angle cylinders. I did not use a cross over relief valve. I thought there was a relief valve built into my Kioti DK45 remote control valve.

Long story short, pushing snow banks back to get at some logs, I blew a hydraulic hose. It poped like a ballon. Guess I will be adding cross over relief shortly. And yes, I should have been using the bucket, but it was 3 miles away at the time.

 

[mpham]

That sucks! At least the hose blew instead of damaging a piston though.

 

[vtsnowedin]

I need to eat crow. Awhile back I converted an old Fisher plow to QA. I extended rear remotes to front of FEL and used QD's for connecting to angle cylinders. I did not use a cross over relief valve. I thought there was a relief valve built into my Kioti DK45 remote control valve.

Long story short, pushing snow banks back to get at some logs, I blew a hydraulic hose. It poped like a ballon. Guess I will be adding cross over relief shortly. And yes, I should have been using the bucket, but it was 3 miles away at the time.

Your not alone. I managed to pop one hose myself and will be addding a cross over relief before next season. The problem is that with the control lever in closed position the fluid on the plow side of the control valve is isolated from the relief valve built into the system.

 

[J_J]

Some valves have work port relief built in

 

[vtsnowedin]

Some valves have work port relief built in

You would think they all would if it is feasible. Apparently JDs rear remotes are not.

 

[oldnslo]

Work port reliefs are usually an option on higher flow valves like those used are larger Ag tractors. Valves used on CUT's are lower flow lower cost valves with less features and they typically exhaust to tank so you cavitate one side of the cylinder but protect the other.

Are the cylinders in question single or double acting? If double acting it will only protect for part of the stroke while retracting. Reason being, The volume of fluid in the blind or cap end of the cylinder is greater than the volume in the rod end.

 

[vtsnowedin]

Work port reliefs are usually an option on higher flow valves like those used are larger Ag tractors. Valves used on CUT's are lower flow lower cost valves with less features and they typically exhaust to tank so you cavitate one side of the cylinder but protect the other.

Are the cylinders in question single or double acting? If double acting it will only protect for part of the stroke while retracting. Reason being, The volume of fluid in the blind or cap end of the cylinder is greater than the volume in the rod end.

In my case they are single acting cylinders on a Fisher plow. When feeding pressure to one the return of the other is open but when the control returns to closed they are locked . Fine until the full weight of the tractor comes against the full cylinder when pushing into a frozen snow bank with the leading side of the plow. A cross over relief valve will allow the two cylinders to balance. I just need to find one set to open at pressures above the 2700psi of the JDs working pressure and below the yield strength of the cylinders and hoses.

 

[J_J]

How about something like this.

Surplus Center - 1/2 NPT 30 GPM 1500-3000 PSI HYD CUSHION VALVE

 

[vtsnowedin]

How about something like this.

Surplus Center - 1/2 NPT 30 GPM 1500-3000 PSI HYD CUSHION VALVE

Probably just the thing. Have to get a couple of short hoses and a couple of 1/2" npt Ts and I should be all set. Thanks for the link.

 

[CJONE]

Probably just the thing. Have to get a couple of short hoses and a couple of 1/2" npt Ts and I should be all set. Thanks for the link.

You don't need to T anything, the T is the X over relief. You just add 2 short hoses and connect to the valve. I usually set these valves on my test bench and at about 3K. CJ

 

[seacap04]

Sorry been too busy to ck thread.

mpham, ageed includind the sucks. I was lucky that hose blew about 2" from hose end. I use reusable ends so it was only a 20 min fix.

vtsnowedin, I was doing just what you described when I blew hose. I also have single acting clyinders on a old fisher plow.

J_J, That is exactly what I should use. I am still looking for it, but somewhere around here I have a similar valve that I used as a brake valve with relief on a winch I used on a work boat I used to own. It probably will not work. I think I remember several inlets and outlets and would be more of use on double acting cylinders.

CJONE, 3000 is where I would start.

Thanks all

 

[vtsnowedin]

You don't need to T anything, the T is the X over relief. You just add 2 short hoses and connect to the valve. I usually set these valves on my test bench and at about 3K. CJ

I take it that means there are two inlets and two outlet ports on the valve itself? That would work.

 

[CJONE]

I take it that means there are two inlets and two outlet ports on the valve itself? That would work.

Part # DRV-4HH I think. 4 ports A and C ports go to cylinder and B and D ports to valve. You can reverse it but cannot mix the ports. The A and B ports X over to the D and C ports and vise versa. CJ