black body radiation

Geo-TH,In · Nov 24, 2016

Just how important is black body radiation when it comes to tractors? I know radiators are painted black to radiate heat.

Has anyone paint their hydraulic cylinders on backhoes painted black? Does it do any good? The reason I'm asking is my wiper seals on cylinders are cracking, looks like heat stress along with age.

I wish I had a safe place to install a hydraulic cooler on my little terramites, but there is absolutely no safe place to install one. So I'm looking for an alternative way to cool my 10 gallons of hydraulic oil, which is 10w40 motor oil, per manufacture's recommendation. After about 200 hours, my hydraulic oil smells burnt.

I may be looking for a small 12v fan to blow air over hydraulic pump and install expanded metal covers instead of solid metal covers over pump and transmission.

jeffcat · Nov 24, 2016

This might help. Look around in the junk yard. The little tiny coolers that are used for tranny and power steering lines might do for you. If you put one in the return line it should work. They are pretty thin and compact. Look in the front of a Ford expedition right behind the grill. There are a couple of them.

Texasmark1 · Nov 24, 2016

Agree on the inline cooler in hydraulic line on open center system where fluid is continually moving, if the tractor doesn't have one otherwise. Problem I see with painting the cylinders is:

Mass to be cooled
Lack of exposed surface area
Thickness of barrier (the case) that has to be overcome
Flow rate in cylinder....essentially 0

Heat transfer is weight of fluid movement, time, temp differential and barrier. That's how I used to measure the heat generated by a complex object.....put in a well insulated box, measure the flow in and out in #mass/unit time and measure the delta T. Answer in watts.

Geo-TH,In · Nov 24, 2016

Tex,
If you ever worked on a terramite, you would see there is no place to put a cooler. Engine is air cooled and muffler is in engine compartment. The engine compartment will only heat the oil, not cool it. I would make a cooler out of copper pipe if there was room. I have to come up with something else. geo.

Bill in IL · Nov 24, 2016

Would it be possible to add hydraulic capacity somewhere at the resevoir? Another 5 gallons in your system would help to absorb more heat giving you more working time for the oil to get to the same temp.

Could you add a heat sink to the side of the hydraulic tank with a fan? I am not familiar with a terramite other than what I have read from you does it use the rear end as a hydraulic reservoir or a separate tank?

It might be a good application for synthetic motor oil as it can handle higher temperatures and still remain stable.

JD Seller · Nov 24, 2016

George they make smaller coolers that have a 12 volt fan to move the air across them. You should be able to make one by using a aftermarket transmission cooler and a small heater fan.

sms · Nov 24, 2016

Sounds like you need a cooler,,,,,,,,,,full of refreshments. Take a break and give the little guy one too. Sorry, just trying to be funny. I'm bad that way also, once I start I want to keep going until it's done. Good luck.

MarkB_MI · Nov 24, 2016

I doubt the color of your cylinders will have much of an effect on oil temperature. The problem is that the larger the cylinder the less surface area you have relative to the volume of oil inside. (Circumference increases directly with diameter, but cross-sectional area increases as to the square of the diameter.)

Maybe the solution is to switch to synthetic oil, which (supposedly) handles higher temperatures than dino oil. Yes it's a lot more expensive, but might pay for itself in the long run if you never have to change it.

Bob · Nov 24, 2016

According to Mythbusters, the insulating effect of the extra coat of paint will negate any possible "black body radiation" heat radiation.
NO

buzz saw · Nov 24, 2016

(quoted from post at 08:47:29 11/24/16) George they make smaller coolers that have a 12 volt fan to move the air across them. You should be able to make one by using a aftermarket transmission cooler and a small heater fan.

Nothing here that hasn't already been said but as usual JD is right. My mechanics service truck has a crane, welder and air compressor, all hydraulic driven (yes even the welder). It makes a lot of heat, especially if you are running all three together. It has a cooler about the size of an automotive transmission cooler with a 12 volt thermostatically controlled fan in the return side. Amazing how well it works.

Gambles · Nov 24, 2016

Years ago, I took a college chemistry class and one of the experiments was to see how much faster a black radiates heat OFF of an object. We all know that a black object will absorb heat when sitting out in the sun, but radiators are black to aid in getting rid of the heat. We did several experiments that showed a black object will melt ice quicker than a light object when the object is filled with ice water. Having an object that is black will radiate heat quicker than a light object, but when the object is out in the sun, who knows?

Dune Country · Nov 24, 2016

A lot of race car engines are painted black, just sayin :wink:

MARK ROBKE · Nov 24, 2016

I am sure you have studied it out,but I would run the lines outside the engine compartment somewhere and mount a cooler,even if I had to build a guard a round it.Air cooled engines run real hot,and with your exhaust in there too,you need the hydraulics somewhere else.The machine may not be designed for what you are using it for-light duty perhaps;so you may need to may a product improvement.I doubt painting your cylinders would have any effect on the temperature of the hydraulic fluid.Get an infra red gun and check.Mark

Geo-TH,In · Nov 24, 2016

sms,
All ready attached a cooler. Doesn't really help.
geo

Geo-TH,In · Nov 24, 2016

Bill,
I have two terramites, one has a larger hydraulic reservoir. The oil in larger reservoir still gets a burnt smell.

Thermometer shows a rapid increase when driving, pushing hard, or climbing hills. Just digging with backhoe, temps remain good.
geo.

Geo-TH,In · Nov 24, 2016

Bob,
You at least address my answer question, thanks.
geo.

Mike M · Nov 24, 2016

George our machines we make at work have oil coolers mounted in the top of the limb riser. Maybe you can plumb one up on top of you roll cage ?

Texasmark1 · Nov 24, 2016

Yes I am not familiar with your application, but you asked about painting your cylinder black to benefit from the physics of black body radiation.

I just responded to that question. How you solve your problem is your doing. I just piggy backed on another YTer's suggestion on what device would work better and why.

Geo-TH,In · Nov 24, 2016

Mike
I have difficulty keeping a mirror on my tractor. I run it though too much brush and would damage anything not hidden inside tractor.

There is no room for an oil cooler unless I try to make one out of copper and put it near the pump. That would take some pondering and yankee engineering.
geo.

Geo-TH,In · Nov 25, 2016

I park all tractors inside. The roll cage just clears garage door by 1/4 inch.

Been thinking of a way to put a copper heat sink on pump and installing a small fan.

I'm also thinking there is a design flaw,
no cooler.

George

TGP · Nov 25, 2016

Maybe it's the quality of seals used?

Sitting in the sun really hurts, but you said you keep it inside,
So I'm back to the quality of cheaper aftermarket parts.

Doesn't your hoe already have a cooler from the factory?

Tom

Deutz Lover · Nov 25, 2016

There is a lot of misunderstanding about black-body radiation.
This is really only effective at much higher temperatures than a tractor engine gets. Black bodies are more effective a heat absorbers than transmitters at normal temperatures. For instance a black painted car will get hotter than a white painted car. Convection fins are a lot better at removing heat than a black body for this purpose. Color does not matter as much on these as surface finish.

A very smooth polished surface is not as good at convection cooling as a rougher surface because air flowing over the fins does not contact the metal because of laminar air flow across polished surfaces. This is the reason intake manifolds are not supposed to be polished compared to the exhaust ports and manifolds on carbureted engines. In this case the purpose is to create turbulence to mix the fuel/air. The fins on air cooled motors should not be smoothly polished so that the heat can be transferred to fresh air at the metal/air interface which is not as efficient when the surface is smoothly polished.

A thin paint (.001") really does not impair heat flow that much.

Geo-TH,In · Nov 25, 2016

Quality of seals doesn't cause oil to smell
brunt.

I get seals from hydraulic shop that
rebuilds cylinders.

black body radiation

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