Hypothetical question on pressure bypass

   / Hypothetical question on pressure bypass #1  

jmc

Elite Member
Joined
Jul 21, 2003
Messages
3,083
Location
SW Indiana
Tractor
Ford 1920 4x4 (traded in on Kubota). Case 480F TLB w/4 in 1 bucket, 4x4. Gehl CTL60 tracked loader, Kubota L4330 GST
Hello All,

Let's say I have a hydraulic top link on a 3 PH and I'm using a back blade (but not adjusting the top link) when I hit an obstruction. If the resulting pressure in the top link cylinder from this external load exceeds the bypass pressure setting, does the bypass valve open?

Thanks.

John
 
   / Hypothetical question on pressure bypass #2  
Hello All,

Let's say I have a hydraulic top link on a 3 PH and I'm using a back blade (but not adjusting the top link) when I hit an obstruction. If the resulting pressure in the top link cylinder from this external load exceeds the bypass pressure setting, does the bypass valve open?

Thanks.

John
To protect from that external "shock", you need a "shock" Releif Valve, RV ,between the Control Valve, CV, and the cylinder (aka port releif valve).....then, yes, the RV will open.
This picture shows a double crossover RV....
crossove_RV_1_to_2.jpg
 
   / Hypothetical question on pressure bypass #3  
Hello All,

Let's say I have a hydraulic top link on a 3 PH and I'm using a back blade (but not adjusting the top link) when I hit an obstruction. If the resulting pressure in the top link cylinder from this external load exceeds the bypass pressure setting, does the bypass valve open?

Thanks.

John

The short answer is NO. The reason is because the work ports of the valve are blocked when the valve is in neutral, and the PRV is on the IN port of the valve.
 
   / Hypothetical question on pressure bypass #4  
The short answer is NO. The reason is because the work ports of the valve are blocked when the valve is in neutral, and the PRV is on the IN port of the valve.
Kennyd!! I hope I did not express my self that bad so I got

of course the pump protecting PRV can never protect from external force shocks......;)
 
Last edited:
   / Hypothetical question on pressure bypass #5  
Kennedy!! I hope I did not express my self that bad so I got

of course the pump protecting PRV can never protect from external force shocks......;)

I was just saying it in a different way, that's all;):D
 
   / Hypothetical question on pressure bypass #7  
Some valves also have work port relief in addition to PRV.
 
   / Hypothetical question on pressure bypass
  • Thread Starter
#9  
Thanks, everyone, for the replies. I should have known it would't be simple.

John
 

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