Don't try this before answering.
Let's take a TEN2 (R134 TEV from Danfoss) and fit an orifice in it.
Connect the inlet to nitrogen and the outlet of 1/2 to a pressure indicator.
Apply pressure of 30 bar on the inlet. What happens on the outlet?
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Don't try this before answering.
Let's take a TEN2 (R134 TEV from Danfoss) and fit an orifice in it.
Connect the inlet to nitrogen and the outlet of 1/2 to a pressure indicator.
Apply pressure of 30 bar on the inlet. What happens on the outlet?
hi peter.
please tell us.
I will not try it anyway. I have a feeling the consequences are still on the ceiling.
chemi :)
Or what do you think that should happen? What do you expect?Quote:
Originally posted by chemi-cool
hi peter.
please tell us.
I will not try it anyway. I have a feeling the consequences are still on the ceiling.
chemi :)
What do you mean Chemi with "the consequences are still on the ceiling"
With many post, i have to look in a dictionary for expressions, quotes, words, especially those of Marc.
Also for this reason is this forum usefully for me.
Peter Just a guess but you would probably get a combination vapor and liquid,
Roger:confused:
Hi Peter:)
I would think the valve would slam shut and little or nothing would come out of it, but I really wouldn't like to test that theory:( :(
Regards. Andy.
Yes, or you blow the head off it :(Quote:
Originally posted by Andy
Hi Peter:)
I would think the valve would slam shut and little or nothing would come out of it, but I really wouldn't like to test that theory:( :(
Regards. Andy.
Blow the head off:confused:
No, you can safely test it till 35 bar.
We needed to test them at 30 bar according to a controller when doing a PED test.
We had following set up from which I posted some pictures in thread Plate cooling.
We had a coil underneath a stainless steel plate.
Thereafter a static evap which we also connected.
Connection: liquid 3/8 in - T 3/8 - divided to each TEN2 - each TEN ejects in his evap - LP coming out both evaps connected in a 5/8 T - final 5/8 out of the counter.
Before installing the counter we did a pressure test like we always did in the past.
We pinche the 5/8 and soldered it closely. In the 3/8 we installed a schraeder valve. Pascal, our tech pressure tested it via the schraeder on 25 bar and left it there until the next morning.
Pressure had dropped from 25 bar to 5 bar.
He had other work to do, so put some R22 into it till 5 bar and then increased pressure with nitrogen till 25 bar. Controlled in the afternoon (pressure decreased to 18 bar) with the old fashioned leak lamp (still aslo my favourite leak searching device) Found no leak. Pascal had to leave the site to do a repair but not before he increased pressure again to 30 bar.
Next morning: pressure on 10 bar.
I told him I shouls help him the next morning searching the leak, hopefully not in the coil undernetah the ss plate.
So what we did (pressure dropped to 10 bar) searching for a leak for at least 20 minutes (with 2 persons) - nothing.
I installed also a schraeder in the 5/8 and connected a pressure gauge. Applied pressure on the common inlet of the 2 TEVs and pressure on the outlet very slowly increased to 5 bar. Heated the bulb with my leak flame, nothing happened.
I thought a restriction in the orifice but in both ?????
Removed orifices and installed twice a 6 to be sure. Same result.
Removed ext. eg. ofthe TEN, plugged it of, same result.
Finally took a new TEN2 and did a liitle set up as I described at the start of this thread. Connected a reduction nut of 3/8 F -->/1/4 M on the outlet and a 1/2 - ->1/4 on the outlet.
Pressure tested inlet on 30 bar and outlet goes till 6 to 7 bar and that's it, even if you heat it with a cigarette lighter to 50°C.
did the test als owith anbother TEN with same result.
This was strange.
So can someone continue this story with an explantion because most of those I have spoken all said "Well,.. pressure should stabilise to same pressure as inlet"
And nobody in this thread was 100% sure of his answer I think, even of how far you can pressurise it, so ...i'ts a litlle confusing.
morning peter,
I would check the pressure gages just to be sure.
you can apply the pressure on both sides of the TEN and see what will hapened.
I also think, that andy has a point.
let us know how it goes.
chemi
Chemi,Quote:
Originally posted by chemi-cool
morning peter,
I would check the pressure gages just to be sure.
you can apply the pressure on both sides of the TEN and see what will hapened.
I also think, that andy has a point.
let us know how it goes.
chemi
Factory (on the other side of my street) where counter is is closed today.
Gages reads correct.
We did it also the reverse way (applying pressure on the outlet of the TEN) Chemi, same result.
Andy, you wouldn't like to test the theory because of what? Exploding of the valve? You can safely test it till 35 bar and then there is still some safety margin of 1,5 to 2.
But it remains something we - and others in this thread - hadn't expected and with which we lost a lot of valuable time before we realised that we hadn't a leak. We almost ordered disassembling the counter.
We now applied pressure on both sides (5/8 and 3/8) to be sure that counter is leak tight. Otherwise we will block the further progress of the ongoing works of the van.
But I will do the test again next week on a TEN2 which isn't connected to an evaporator.
We've scheduled the start up end next week.
Will take some pictures of it if I don't forget it.
External egalisation connected or not, result didn't changed anything.
ok marc,
please explain why?
chemi
Will do the test Monday again with an open external equaliser.Quote:
Originally posted by Marc O'Brien
Only if the external equaliser was open to atmosphere would the full 30bar be seen in the evaporator. But internal leakage would result in some nitrogen loss to atmosphere from the uncapped external equaliser.
thanks marc.
chemi :)
no, but it helps me to understand, what exactly do you mean.
chemi :)
Marc is of course correct concerning the TEV pressure test. Any static pressure test of the system's low side with either the TEV's equalizer connected or capped off must be done downstream of the TEV. Conversely, any pressure test of the system's high side with either the TEV's equalizer connected of capped off must be done upstream of the TEV
The Prof has had several occasions to explain to OEM QC folks why applying pressure to one part of the system having a TEV will not equalize thru the entire system.
One way to get around this problem is to cap off the equalizer line itself and leave the equalizer connection on the TEV open to atmosphere. With internally equalized TEVs, you're out of luck... :(
hi marc,
your modesty should be admired. :)
chemi
thats allright mark, just kidding,
never realy had the need to check a system with such high pressure, so I was wondering why.
as a gentelman gesture to another one, it was a good explanation.
chemi :)
According to the VLAREM II law in Belgium (environemental law), we have to pressurise 1,5 x max operating pressure, therefore not exceeding the max allowable pressure of the components.Quote:
Originally posted by chemi-cool
thats allright mark, just kidding,
never realy had the need to check a system with such high pressure, so I was wondering why.
as a gentelman gesture to another one, it was a good explanation.
chemi :)
So this can be 25 bar.
In VLAREM I (15 yeras ago) could be read : Every pressure vessel, including ***** vessels has to be pressurised each 5 year with water"!!!
But ever pressurised tubes in an evaporator??
You can go almost to 100 bar before it explodes. Tried it myself.
Do you have an idea of the burst pressure of a simplet PET cola bottle?
Now the Prof understands how Danfoss has been able to sell so many filter-driers in Belgium... :DQuote:
In VLAREM I (15 yeras ago) could be read : Every pressure vessel, including ***** vessels has to be pressurised each 5 year with water"!!!
I did the pressure test with the Danfoss TUAE R507 TEV, with MOP at -20C. Just to find out how high the leakage rate was with TEV fully closed.
When pressurizing the inlet with 18 bar of air (sorry, I'm a hobbyist), the pressure at the coil outlet rose to 2 bar, and stayed there. After 24 hours, pressure was still at 2 bar.
This showed me that I could not expect TEV leakage to equalise pressures during off-cycle in a reasonable amount of time.
Agree 100%, same result. Some other posted different opinions without trying it themself.Quote:
Originally posted by DaBit
I did the pressure test with the Danfoss TUAE R507 TEV, with MOP at -20C. Just to find out how high the leakage rate was with TEV fully closed.
When pressurizing the inlet with 18 bar of air (sorry, I'm a hobbyist), the pressure at the coil outlet rose to 2 bar, and stayed there. After 24 hours, pressure was still at 2 bar.
This showed me that I could not expect TEV leakage to equalise pressures during off-cycle in a reasonable amount of time.
Nitrogen's critical temperature is -147C....Quote:
Originally posted by shogun7
Peter Just a guess but you would probably get a combination vapor and liquid,
Roger:confused:
Though, if you used WAY more pressure than 30 bar, and you left the output open to atmosphere, you might encounter droplets of liquiefied nitrogen :)
(but I think you will find pieces of the TEV orbiting the earth before that happens)
hey that is not strange at all:
You are looking at a valve that should be closed when high pressure is on it.
The membrane is pushed to a close as the topside is pressed by your nitrogen.
So it will happen both sides. Only way to test it is take out the insert.
If you take off the equalisation line and put it in open air while charging it will be fine. After charging mount again and pressure test.
It looks the same as with a MOP filling. even without a MOP there is a maximum to it.
If you reaaly want to know everything then use a pressure and a temp and make a scale of it. Same problem by the way with these electronic valves.