room temperature
room temperature
(OP)
We have a hydraulic system to raise and lower 6' gates in a dam. The manual for the dam states that the control building temperature should not be allowed to drop below 50 degrees farenheit to keep the hydraulic systems warm. The dam was built in 1967. Now I'm wondering why the temperature has to be maintained since many machines work outside in much colder temperatures.





RE: room temperature
Performance of the system would degrade as the oil became thicker. The primary risk would be to the pump as it would not be able to fill as easily as it would with warmer, less viscous oil. Pumps that cannot suck enough oil in tend to die very quickly.
Other machines that work outside are designed with low temperatures in mind. Bigger pump inlets, flooded pump suction lines, reservoir heaters.
it is often the case that such notices are placed in the manual retrospectively. That is someone forgot to install a heater and rather than spend some money they just draw up a quick warranty "get out".
'hope this helps..
Adrian
RE: room temperature
Mobile systems do startup at lower temperatures. General practice is to run the system without doing work until the system warms.
What fluid are you using? The temperature caution statement may no longer apply for the fluid you currently use.
Ted
RE: room temperature
I also agree with hydtools on the viscosity. You should be able to switch to a multi-viscosity oil to help run in cold conditions.
ISZ
RE: room temperature
I was hoping a better oil would allow us to lower the temperature but wasn't sure if there might be some other problem that wouldn't occur to this civil engineer. It costs us about $1600 a month to heat the control building so pehaps we can save a few dollars.
RE: room temperature
Here is a piece of literature from Chevron.
https://w
Other suppliers can provide information too.
Ted
RE: room temperature
http://www.hydrosafe.com/products/viscosity.htm
Ted
RE: room temperature
- Does the pump run all the time or just as needed, and if so how often is this?
- Does the oil run out to each lock? If so is it in the elements or protected?
- What kind of pump do you have? (gear, piston, etc.) If piston is it fixed displacement or variable?
- What pressure does the pump see at stand-by?
Piston pumps do not like to have inlet vacuum. It pulls the slippers off of the swash plate and can cause havoc. A variable displacement pump could be a little better if there is no flow demand at start-up. Gear pumps can generally tolerate some vacuum for ~30 seconds during the occasional cold start. My experience with engine driven pumps shows that the oil acts live a viscous plug - during cranking it doesn't want to move a causes high vacuum, but once it starts moving (10-30 seconds) the vacuum drops quite a bit and becomes acceptable. An electric motor application would be similar but you don't get the luxury of the slow cranking period.
ISZ
RE: room temperature
More modern fluids and a tank heater might be a fairly easy fix there.
Slightly OT, but if the issue is cold oil in the lines, and line volume is more than the cylinder volume, the oil never comes back to the tank. It just shuttles back and forth in the lines and stays cold. I've seem aplications that use 4 lines, 2 for A and 2 for B, with checks at each end. Oil goes out in one line and back in the other so it cycles through and warms up. Also used in extremely dirty applications where dirt builds up in cylinders from rod seal ingression if it doesn't cycle and flush.
kcj
RE: room temperature
RE: room temperature
Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING
RE: room temperature
RE: room temperature
The Actuators still have old oil but can be cycled once or more and then reflush that oil back to tank.
Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING