Temp Gauge for Hydraulic Fluid

[K5lwq]

I upgraded the pump on my LK2554 to a 10 GPM pump from a 7 GPM pump. With the increase in flow, I became concerned that the hydraulic oil might overheat. The only way I had to keep a eye on it was touching one of the fittings. It would get hot enough that I could not hold my finger on the fitting. So, is that too hot? Who knows.

So, today I decided to figure out a way to put a gauge on it that I can watch for overheating. My first plan was to tee into the tank return line off of the valve. No hydraulic tee available in my small town. Then I found a plug in the side of the filter block and was able to get the fittings to install the probe.

Now I will have something to reference.

 

[K5lwq]

Well, either I have nothing to worry about or this is not a good place to have the probe. I ran the mower for about 1.5 hours this morning, working the grapple often the whole time, and the gauge never left the resting position of 130 degrees. I am not sure what to think. I wish I could have found a gauge that started around 80 degrees so I would at least know it is working.

Does anyone have an opinion or suggestion on how to this better? Or I am worried for nothing?

 

[RickB]

When I saw your photos yesterday I thought the adapters would keep the bulb out of the oil flow and make the gauge read cold. I still do.

 

[K5lwq]

That swivel was the only way I could get to 1/2 NPT with what I could get local. I will see if I can find something tomorrow that will shorten things up.

 

[davrow]

Um, increased flow doesn't mean increased pressure. Temp with new pump should be exact same.

 

[K5lwq]

Um, increased flow doesn't mean increased pressure. Temp with new pump should be exact same.

I agree and understand pressure is the same. Mainly because I set the pressure using a gauge to 2100 psi. I disagree though that the temp would be the same. If you circulate fluid faster through a system with restriction points, such as a valve or fittings, temperature will increase. It creates more friction. However, I am not all that smart so I could be wrong. :confused3:

 

[davrow]

If you circulate fluid faster through a system with restriction points, such as a valve or fittings, temperature will increase. It creates more friction.

My contention is that there is no increased flow, nothing is moving faster, due exactly to the restriction points. Without increased pressure, there is nothing to push more fuid through those points.

What you have now is the ability to run more implements simultaneously.

 

[K5lwq]

My contention is that there is no increased flow, nothing is moving faster, due exactly to the restriction points. Without increased pressure, there is nothing to push more fuid through those points.

What you have now is the ability to run more implements simultaneously.

I guess I just don't understand. If I have increased flow rate from 7GPM to 10GPM @ operating RPM and have not increased line size, I will create more turbulent flow as a result of increased velocity. Turbulent flow = friction that creates more heat.

Maybe this link will help explain what I am saying.

 

[K5lwq]

My contention is that there is no increased flow, nothing is moving faster, due exactly to the restriction points. Without increased pressure, there is nothing to push more fuid through those points.

What you have now is the ability to run more implements simultaneously.

Also, why do you say nothing is moving faster? This is a write up I did when I changed the pump. At the end you will see the direct comparison, based on time, between the two pumps at different RPMs. As you will see, things are much faster with the new pump.

 

[kthompson]

Infrared hand held thermometer for 30 to 40 dollars are lowes. Can check any point you want to with one tool.

 

[RickB]

My contention is that there is no increased flow, nothing is moving faster, due exactly to the restriction points. Without increased pressure, there is nothing to push more fuid through those points.

What you have now is the ability to run more implements simultaneously.

There’s so many things wrong here I don’t know where to start.
He put on a larger pump; how is there not more flow?
How do you know that restrictions are limiting flow?
Let’s pretend there ARE restrictions. How would they NOT create more heat?
If there happens to be restrictions to the additional flow, measured pressure between the pump and restriction WILL be higher.
When valves in an open center system are plumbed in series without a flow divider, simultaneous operation is not a given, only a possibility dependent on variables not known here.

 

[RickB]

Infrared hand held thermometer for 30 to 40 dollars are lowes. Can check any point you want to with one tool.

And there is a useful tool available for other things.

 

[Texasmark]

Infrared hand held thermometer for 30 to 40 dollars are lowes. Can check any point you want to with one tool.

They are getting more popular these days HF has them on for 20 bucks from time to time. I have 2 and both work just fine. I was going to suggest the same as I use mine on everything. Really amazed at how cool things really run when you expect them to be sizzling hot.

As I recall at about 70C if you put your finger/hand on an object you have to immediately take it off. No burn involved, just uncomfortable enough to make you want to do it. That's 158F if I did my arithmetic correctly. For a benchmark, US domestic hot water heaters (of which I know) in the N position produce 140F water.

Fluid can get well over 230F before you have to start worrying about temp.

 

[K5lwq]

Thanks Rick for clearing that up. I thought for a second that I was loosing it.

Thanks everyone for your help. I will get a infrared thermometer to check things out. I still would like to get the gauge working if I can so I can monitor temps on a ongoing basis. My hope is to keep the temp below 180F if possible.

 

[countrybumpkin]

Should be a good location for your gauge once you get the probe in the fluid flow.