Position of the suction outlet and return ports.

[desert trader]

I have noticed on most hydraulic reservoirs that the suction and return ports are at about the same level near the bottom of the tank. Is there a reason for this or can the return port be put in at the top.

 

[dodge85rc]

Yes the return line can be at the top.

 

[AKKAMAAN]

I have noticed on most hydraulic reservoirs that the suction and return ports are at about the same level near the bottom of the tank. Is there a reason for this or can the return port be put in at the top.

reservoir design is a special "science"....a couple pages can be said about reservoir design....

here is a couple about your question...

• 
  Cooler fluid have higher density and will go to bottom of reservoir, so that is the reason the suction port is at bottom

• make sure return is securely below lowest fluid level, if not, air bubbles will get into fluid...it do not have to be at bottom....

• also keep suction and return as far apart as possible to increase cooling capacity of reservoir.....it is also preferable to have a separating "wall" inside the reservoir, with some good size openings at the bottom corners

 

[desert trader]

I'm switching from the tractor's hyd to a pto pump and the reservoir is in the loader frame and the return line port is at the top and the fluid level will be below the port.

 

[AKKAMAAN]

I'm switching from the tractor's hyd to a pto pump and the reservoir is in the loader frame and the return line port is at the top and the fluid level will be below the port.

It is going to aerate the fluid......then it will depend on if fluid have enough time in the reservoir to let air out, before it goes to suction again....You do not want compressable air in a fluid for a hydraulic (static) system....

 

[J_J]

I'm switching from the tractor's hyd to a pto pump and the reservoir is in the loader frame and the return line port is at the top and the fluid level will be below the port.

If the reservoir cap is at the top of the arms, perhaps you can add another section of hose connected to a bulkhead fitting inside the arms and extending down about 6 in off the bottom.

There is a remedy for just about anything. Just have to find one that will work.

 

[IceStationZebra]

The return port does not need to go to the bottom, it just needs to be covered in oil at all times to prevent added aeration. You are not going to be able to measure the temperature difference by moving the return to the bottom of the reservoir. It is more important to the keep the return and suction separated to help deaerate the oil.

Tank volume also plays a big role in deaeration. You can get away with fairly small reservoirs (like 25% of the pump gpm / 15 second turnover) provided you don't have aeration problems. I know that you need a reservoir with at least a 1 minute turnover if you do have aeration with ISO 32 or 46 oil. At work we cut the side off of a reservoir and install a sheet of plexiglass - you could watch the bubbles just float around! And like AKKAMAAN said use a divider where possible. Off-road OEMs don't normally use them as it adds quite a bit of cost.

ISZ

 

[Wayne County Hose]

reservoir design is a special "science"....a couple pages can be said about reservoir design....

here is a couple about your question...

• 
  Cooler fluid have higher density and will go to bottom of reservoir, so that is the reason the suction port is at bottom

• make sure return is securely below lowest fluid level, if not, air bubbles will get into fluid...it do not have to be at bottom....

• also keep suction and return as far apart as possible to increase cooling capacity of reservoir.....it is also preferable to have a separating "wall" inside the reservoir, with some good size openings at the bottom corners

AKKAMAAN, I love your posts but really had to laugh at this one. I'll let you figure it out, lol!:laughing:

 

[AKKAMAAN]

AKKAMAAN, I love your posts but really had to laugh at this one. I'll let you figure it out, lol!:laughing:

Thanx Wayne!! Sometimes finger types faster than brain wants them to....hahhaha....so now to the task....there might be a few options that could have meade you crack up here....the high lighted red sentence might be the one....could be subject to mbe mis-interpreted....I skip "the english" and just post a pic to explain what I meant.....

Please keep replying...it SURE IS APRIL FOOLS DAY!!:laughing:...If there is more that I do not notice!!

quoting my self her.....LOL

reservoir design is a special "science"....a couple pages can be said about reservoir design....

here is a couple about your question...

Cooler fluid have higher density and will go to bottom of reservoir, so that is the reason the suction port is at bottom
make sure return is securely below lowest fluid level, if not, air bubbles will get into fluid...it do not have to be at bottom.... also keep suction and return as far apart as possible to increase cooling capacity of reservoir.....it is also preferable to have a separating "wall" inside the reservoir, with some good size openings at the bottom corners

 

[Wayne County Hose]

I just always figured the best reason the suction port is at the bottom of the tank is because that's where gravity pulls the fluid. Wouldn't work too well if the suction port was at the top of the tank. :confused2: