|
|
Post by ChrisJ on Dec 15, 2014 21:46:48 GMT
You know that pisses me off. Scotty gave them the formula for that in what, 1986? But do you see it anywhere?  On a serious note, why does the left tank stay frosted all of the way up and yet the right tank only half way or a little less? Shouldn't the liquid be equalized on both sides during off periods? No you don't see it anywhere; it's transparent!  I'm thinking they are keeping it a military secret. The current generation of stealth aircraft are indeed completely invisible. It usually takes 30 years for military tech to be revealed to the public, so another couple of years should do it. The frost line is level; your floor is tilted.  Differences in internal distribution? Remember that liquified gasses always move to the coldest point (lowest pressure), so tiny differences in temp or loading? It just seems to me that every time it comes up, a full charge is described as one side frosted to the top, the other half way up. All of them I have seen have the crossover tube well above the liquid level, curved in the middle to be even higher; there isn't going to be much flow from one side to the other during off times. It seems like they made it that way deliberately, though I have no idea why.To keep the suction like from sucking up liquid other than oil perhaps? |
|
|
|
Post by cablehack on Dec 15, 2014 22:19:01 GMT
The evaporator patent mentions give some reasoning for the raised crossover tube:  |
|
|
|
Post by blackhorse on Dec 16, 2014 5:59:33 GMT
The evaporator patent mentions give some reasoning for the raised crossover tube: I'm somewhat discombobulated by that last sentence (in the patent attachment). Oil doesn't have to be conveyed through the crossover tube from one side to the other because liquid refrigerant carries it across? Meaning liquid refrigerant flows through the crossover tube? 1) I don't see how that is possible, since the tube is well higher, especially in the middle, than the refrigerant level, and 2) That brings us right back to ChrisJ's observation of why don't the levels on both sides equalize, if liquid refrigerant is passing through the crossover tube as the patent states. Is this the point where the special additive "Magic" is injected? |
|
|
|
Post by cablehack on Dec 16, 2014 6:09:40 GMT
I think it means the oil is carried to both sides by the liquid refrigerant that's in the bottom of the evaporator, but the crossover tube works only for vapour allowing the pressure to equalise in both tanks.
If that is correct then it should be possible to have different refrigerant levels in each tank, but with the same vapour pressure.
|
|
|
|
Post by coldspaces on Dec 16, 2014 6:15:14 GMT
I think it means the oil is carried to both sides by the liquid refrigerant that's in the bottom of the evaporator, but the crossover tube works only for vapour allowing the pressure to equalise in both tanks. If that is correct then it should be possible to have different refrigerant levels in each tank, but with the same vapour pressure. That's the way I read it also. |
|
|
|
Post by blackhorse on Dec 16, 2014 15:22:36 GMT
I think it means the oil is carried to both sides by the liquid refrigerant that's in the bottom of the evaporator, but the crossover tube works only for vapour allowing the pressure to equalise in both tanks. If that is correct then it should be possible to have different refrigerant levels in each tank, but with the same vapour pressure. That's the way I read it also. That would be what logic dictates would be how it works, though the last bit didn't read that way to me. And special reference was made to oil traveling from one tank to the other. Why is that necessary? The suction line draws equally from each, in the center of the crossover tube. Why does oil need to go from one tank to the other? Does the tank that always has the lower frost line do so because it has more oil on top (thus lower liquid refrigerant)? Bringing us back to ChrisJ's question. |
|
|
|
Post by ChrisJ on Dec 16, 2014 15:28:42 GMT
The suction line goes to the right tank, not the center of the crossover tube.
|
|
|
|
Post by jhigdon2 on Dec 16, 2014 18:38:46 GMT
Guinea pig still running. No issues. Box was getting a little cold. (32 deg) Sorry allan! I readjusted to bring it back up to 38 deg. The 123 seems to work just fine, and there is no apparent difference in sound. It does however require different cap tube. The 30" inches of .031 is a little short I think. Run Time are decent but could be improved a bit. On times are 5 on 10 off. It's just gonna take some time to experiment with oil heat, refrigerant charge and cap tube length. One thing I have noticed is that the unit seems to require less run amps with the 123. 2.38 amps. My other CA2 draws about 2.6 amps. Also noticed evap cools faster and it's almost silent. (Very little bubbling noise).
|
|
|
|
Post by cablehack on Dec 17, 2014 1:44:45 GMT
I would have thought the slightly higher pressure of R123 should cause an increase in current draw, rather than a decrease, so some other factor must be evident here.
|
|
|
|
Post by jhigdon2 on Dec 17, 2014 3:46:03 GMT
The 82 deg. Boiling point of the R123 almost made me abandon the whole idea. I initially thought it would just run and hide in the oil sump. It may do just that, if the unit is used in cool Ambient temps. So far I am pleased. I am however borrowing a 25 watt heater from Allan so I can experiment with this theory. At this point in time, it seems like a near drop in substitute non flammable refrigerant for methyl formate. If you have a CA unit with a working float chamber, I believe it would be a drop in replacement, and present no problems. Now I just need to see if oil migration will be a probem. So far though, it still sounds like there is plenty of oil in the sump.
|
|
|
|
Post by cablehack on Dec 17, 2014 4:34:53 GMT
Would 82F vs. 89F really be so critical? The heater could be run from a Variac to simulate lower power heaters, and thus find out how much heating power it actually needs.
|
|
|
|
Post by jhigdon2 on Dec 17, 2014 4:44:00 GMT
Maybe I'm getting a little more forgetful than I thought. I Coulda swore methyl formate had a much lower boiling point. Hmmm.
|
|
|
|
Post by allan on Dec 17, 2014 5:18:58 GMT
Guinea pig still running. No issues. Box was getting a little cold. (32 deg) Sorry allan! I readjusted to bring it back up to 38 deg. The 123 seems to work just fine, and there is no apparent difference in sound. It does however require different cap tube. The 30" inches of .031 is a little short I think. Run Time are decent but could be improved a bit. On times are 5 on 10 off. It's just gonna take some time to experiment with oil heat, refrigerant charge and cap tube length. One thing I have noticed is that the unit seems to require less run amps with the 123. 2.38 amps. My other CA2 draws about 2.6 amps. Also noticed evap cools faster and it's almost silent. (Very little bubbling noise). Lol that's a good one about the 32 degrees John! And I am not the only one on this forum that wouldn't touch a beer or soda that was 38 degrees :-). I believe the goal was "if your beverage don't make your head hurt when drinking it, then it's too warm" |
|
|
|
Post by blackhorse on Dec 17, 2014 5:20:52 GMT
I would have thought the slightly higher pressure of R123 should cause an increase in current draw, rather than a decrease, so some other factor must be evident here. When I converted to 134a from SO2 in a CK, the amps dropped a bit even though 134a is quite a bit higher pressure than the SO2 was. So yeah, there's some interesting effects going on there. |
|
|
|
Post by blackhorse on Dec 17, 2014 5:25:40 GMT
The suction line goes to the right tank, not the center of the crossover tube. Seriously?!? What the heck am I seeing here?:  That would explain a lot though......... |
|
