Capillary tube

[NockE]

Okay, I've read Bowman's article on Phase-Change (http://www.phase-change.com) about DIY phase change cooling.

Can you clear something up for me?

The capillary tube is the tube which leads to the coolingblock

Way it works as I presume: compressor "compresses" gaz to high-pressured gaz, through the condensor it becomes liquid again, through the filter and capillary tube where the liquid "boils off" (other word ????) and absorbs the heat of the die of the cpu and off again to the compressor

I want to know how it works.... ;)

greetz

[TheDude]

Hi NockE,

Bowman is out of town this week, so I will attempt to answer this as best I can.

The capillary tube is used to provide resistance to refrigerant flow, creating a high and low pressure area. In the evaporator or low pressure area, heat is absorbed, changing liquid to a vapor, and in the condenser or high pressure area heat is given off, changing the vapor back to a liquid. If there were no resistance, pressures would be the same throughout and the refrigerant would circulate with no cooling effect.
The compressor pumps vapor into the condenser. The capillary tube at the other end of the condenser is a smaller diameter which causes resistance, which creates pressure as more refrigerant is pumped thru. The pressure is regulated by how much refrigerant comes in, versus how much is forced through the capillary. The low pressure side is the evaporator side where the compresor is pushing the vapor thru the suction line.
So you have the high pressure side (condenser)..then the capillary tube...then the low pressure side (evaporator)....then the suction line which leads to the compressor where the cycle starts over again.
Therefore your system temperature can be controlled by the length of the cap line. Be very careful when soddering the cap line so as not to get anything inside of it where it will cause clogs.

I am sure that Bowman can explain it better when he returns, but I hope that helps explain the basics. :D

[NockE]

thank you for the explanation ;)

what I actually want to know is which part is going "through" the coolblock

Is that the evaporator?

greetz

[TheDude]

I'm very sorry, but I don't understand what you are asking? What do you mean by "coolblock"? By coolblock, do you mean evaporator? The part that actually sits on the cpu and cools it? Does this diagram of Bowmans help any with your question?

[NockE]

Maybe my question wasn't clear enough, sorry

By coolblock I mean the part that actually sits on the cpu/die. But through that coolblock "something" must pass so the heat is taken from the cpu.

Seen from the picture I guess it is the evaporator where we have the low-pressure area.

[TheDude]

Yeah...coolblock and evap are the same. Bowman will be back in the next couple of days. He designed and made my evaporator...well my whole cooler actually. :D He will be able to answer evap questions of any kind...he's working on a very interesting new design. :D
I want to make a simple chiller from an ac unit I have....similar to what Opp was using....for watercooling my Koolance case. Handmade evaporators are beyond my abilities.

[gecko991]

I just built a flat surface evaporator for my 9800 pro which runs with a small milk cooler condenser. The ID diameter and length of the capillary determines the pressure op range of the application. The longer the cap length the higher the head pressure. Your evaporator suction pressure will increase also.

[TheDude]

gecko991,

Got a pic? :D

Thanks...Welcome to Xtreme!
:toast:

[aenigma]

Originally posted by gecko991
The ID diameter and length of the capillary determines the pressure op range of the application. The longer the cap length the higher the head pressure. Your evaporator suction pressure will increase also.

You got that backwards. ;)
The longer the capillary, the lower the head pressure, lower suction pressure, more subcooling, less heat handling.

[gecko991]

Sorry about that your right I was a little hung over this morning. I do not have any pics yet but hopefully sunday I can hook it all up and grab my friends dig camara for some pics.

[bowman1964]

Originally posted by NockE
Okay, I've read Bowman's article on Phase-Change (http://www.phase-change.com) about DIY phase change cooling.

Can you clear something up for me?

The capillary tube is the tube which leads to the coolingblock

Way it works as I presume: compressor "compresses" gaz to high-pressured gaz, through the condensor it becomes liquid again, through the filter and capillary tube where the liquid "boils off" (other word ????) and absorbs the heat of the die of the cpu and off again to the compressor

I want to know how it works.... ;)

greetz

well i think you might have figured it out on your own by now.but here is a simple way it works...
compressor compresses the gas under high pressure.(pressure is generated by the restriction of gas at the capillary tube)this high pressure gas when cooled by the condensor will condense into droplets forming a liquid that collects in the lower part of the condensor.this high pressure cooled liquid will pass though a filter to collect any mositure or small particals.then move into the capillary tubing,which is nothing more than a way to meter and control the flow of refrigerant.then as it exits the capillary tubing it is exposed to the low side of the system where it quickly evaperates into a gas taking the heat with it.and the suction of the compressor brings it back to start the process over and over again.

[gecko991]

Hello Bowman 1964. Have you experimented with AZ20 yet. Compared to R404A or HP62 at -48F its still 6.9 lbs suction pressure.

[bowman1964]

Originally posted by gecko991
Hello Bowman 1964. Have you experimented with AZ20 yet. Compared to R404A or HP62 at -48F its still 6.9 lbs suction pressure.

well az20 is just 410a and yes it does have a better boiling point.but the added cost isnt worth the 5 degrees of temp drop.i can get 404a easily .410a isnt as easy and cost more i have a new can of 404a heading to me now since i am out personaly.
if i had some 410a i wouldnt mind trying it out.

but to your anser no.i havent had the pleasure of playing with az20 (410a) yet.

[gecko991]

You got a point there. Its rather expensive and we do not run into many clients who desire it. 404A on the other hand is plentiful. I just got a tank of AZ50 also which is similar in pressure.

[NockE]

If I take a quick look to my vapo, I see the capillary tube and from a certain point it is isolated.
So, that spot should be the end of the capillary tube and the begin of the evaporator.

I think I figured it out by now, thx Bowman :toast:
the others to too ;)

greetz