Michael Kellough
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Euro pressure gauge, how to read
- Thread starter Michael Kellough
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Packard
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I’m not sure this is the correct converter. Check it out.
https://www.inchcalculator.com/convert/atmosphere-to-pound-per-square-inch/
https://www.inchcalculator.com/convert/atmosphere-to-pound-per-square-inch/
tjbnwi
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The gauge is reading negitive pressure (vacuum), not pressure.
The gauge has 2 scales, the inner is in bar the outer is in inches of mercury (HG). You can read it directly, you are reading ~27.75"HG which is about as good as it gets for your altitidue.
Here I'm lucky to get to 24"HG, I'm at 6500 feet above sea level.
Tom
The gauge has 2 scales, the inner is in bar the outer is in inches of mercury (HG). You can read it directly, you are reading ~27.75"HG which is about as good as it gets for your altitidue.
Here I'm lucky to get to 24"HG, I'm at 6500 feet above sea level.
Tom
Michael Kellough
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Thanks to you both!
MikeGE
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This question just came up two weeks ago during a discussion with a distant family friend of drawing water out of a well that was 15 meters deep. I recommended the time-proven method of a submersible pump and controller for lots of water or using a hand pump for small amounts of water.
The person I was discussing this with could not comprehend that even if a perfect vacuum existed, it cannot exceed -1 bar, -14.7 pounds per square inch, or -29.95 inches of mercury at sea level, and there will be a maximum height any water column will reach before it stops and cannot rise any farther.
The solution to his problem was to spend the money on a submersible pump and controller, or install a hand pump, and be done with it. When I left him late in the evening, he was still trying to figure out how to use his Kärcher wet/dry vacuum and a garden hose to draw up the water.
The person I was discussing this with could not comprehend that even if a perfect vacuum existed, it cannot exceed -1 bar, -14.7 pounds per square inch, or -29.95 inches of mercury at sea level, and there will be a maximum height any water column will reach before it stops and cannot rise any farther.
The solution to his problem was to spend the money on a submersible pump and controller, or install a hand pump, and be done with it. When I left him late in the evening, he was still trying to figure out how to use his Kärcher wet/dry vacuum and a garden hose to draw up the water.
How to read the gauge?
I would guess if it's in the green it's ok, in the red is not ok [poke]
Someone correct me if I'm wrong, but at -0.9 BAR (or -900 HectoPascal) I believe there is about 13 PSI of atmosphere pressing down on the item you vacuum sucked (sucked vacuum?)
wpz
I would guess if it's in the green it's ok, in the red is not ok [poke]
Someone correct me if I'm wrong, but at -0.9 BAR (or -900 HectoPascal) I believe there is about 13 PSI of atmosphere pressing down on the item you vacuum sucked (sucked vacuum?)
wpz
tjbnwi
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How crazy is altitude on pressure and vacuum???
When I was back home I was about 150 above sea level, hard boiled eggs were about 7-1/2 minutes, water reached a boil @ 212ºF.
Now that I’m at 6500 feet above sea level hard boiled eggs are 17-1/2 to 18 minutes. I had to go out to my truck plug into the ECU to get the barometric pressure at my home, work it backwards to find the temperature the water boiled at. The boiling temp is about 204ºF, wasn’t putting enough BTU’s into the egg in 7-1/2 minutes.
Relearning to bake here has been fun…..
Tom
When I was back home I was about 150 above sea level, hard boiled eggs were about 7-1/2 minutes, water reached a boil @ 212ºF.
Now that I’m at 6500 feet above sea level hard boiled eggs are 17-1/2 to 18 minutes. I had to go out to my truck plug into the ECU to get the barometric pressure at my home, work it backwards to find the temperature the water boiled at. The boiling temp is about 204ºF, wasn’t putting enough BTU’s into the egg in 7-1/2 minutes.
Relearning to bake here has been fun…..
Tom
Michael Kellough
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Did some reading…
If -1 bar = 14.5 psi (minus 14?)
and my gauge is at ~-.88 bar
then .88 x 14.5 = 12.76 psi
Trying to press down some psa veneer that got a little washboardy from high humidity.
Using an 18 x 21 plywood platen yields about 4800 pounds, on both sides.
That’s always mind boggling to me.
If -1 bar = 14.5 psi (minus 14?)
and my gauge is at ~-.88 bar
then .88 x 14.5 = 12.76 psi
Trying to press down some psa veneer that got a little washboardy from high humidity.
Using an 18 x 21 plywood platen yields about 4800 pounds, on both sides.
That’s always mind boggling to me.
Packard
Member
In the early 1980s, I joined a group set on ascending the three major volcanoes in Mexico (which were “extinct” at that time).
They were the 3rd, 5th and 7th highest peaks in the Americas (I think, I have that right—it was a long time ago.)
We climbed them all within 10 days (Popocatépetl, Iztaccíhuatl and Pico de Orizaba), all around the first of the year. On New Year’s day we ascended Popo. One of the climbers carried a small split of champagne with him to celebrate New Years at the summit.
We left base camp at 2:00 a.m. and reached the summit just after noon. We un-roped to sit down and eat lunch. The climber with the champagne brought it out. The rest of the climbers were in awe. We all did everything we could to keep the weight of our gear low and he carried champagne up the mountain.
He carefully removed the cork at nearly 18,000 feet. The cork took off at least 150 feet in the air and the entire contents of the bottle went with it. There was not remaining even one drop of champagne to drink.
I suppose we were lucky that the bottle did not explode. It was filled under pressure at sea level. The pressure must have been extraordinary at 18,000 feet.
By the way, I did predict that the volcanoes would erupt. One of the climbers stood up and peed in the crater. I said, “The gods of the volcanoes will not be happy about that.” [big grin]
Apparently, when it comes to volcanoes, “extinct” is not forever.
P.S.: Apparently my spell checker was not happy with “un-roped” and changed it to “unrobed”. I’m glad I caught that. [eek]
They were the 3rd, 5th and 7th highest peaks in the Americas (I think, I have that right—it was a long time ago.)
We climbed them all within 10 days (Popocatépetl, Iztaccíhuatl and Pico de Orizaba), all around the first of the year. On New Year’s day we ascended Popo. One of the climbers carried a small split of champagne with him to celebrate New Years at the summit.
We left base camp at 2:00 a.m. and reached the summit just after noon. We un-roped to sit down and eat lunch. The climber with the champagne brought it out. The rest of the climbers were in awe. We all did everything we could to keep the weight of our gear low and he carried champagne up the mountain.
He carefully removed the cork at nearly 18,000 feet. The cork took off at least 150 feet in the air and the entire contents of the bottle went with it. There was not remaining even one drop of champagne to drink.
I suppose we were lucky that the bottle did not explode. It was filled under pressure at sea level. The pressure must have been extraordinary at 18,000 feet.
By the way, I did predict that the volcanoes would erupt. One of the climbers stood up and peed in the crater. I said, “The gods of the volcanoes will not be happy about that.” [big grin]
Apparently, when it comes to volcanoes, “extinct” is not forever.
P.S.: Apparently my spell checker was not happy with “un-roped” and changed it to “unrobed”. I’m glad I caught that. [eek]
Crazyraceguy
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It's amazing how "seemingly little" vacuum it takes to crush things.
That was one of the biggest lessons we learned the hard way, when we first got the thermoforming machine at work. We use it to bend Corian sheets. If your form is not strong enough, you end up flattening it.
That was one of the biggest lessons we learned the hard way, when we first got the thermoforming machine at work. We use it to bend Corian sheets. If your form is not strong enough, you end up flattening it.
Michael Kellough
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On my next piece I did a better job sealing and got up to .92 bar, ~13.34 psi. (.92 x 14.5)
Nearly 9000# on a 18 x 37 inch panel.
Nearly 9000# on a 18 x 37 inch panel.
bobtskutter
Member
This is an interesting thread.
That pressure indicator is reading "gauge pressure", not "absolute pressure".
At sea level, ambient pressure is 0 barG, or 1 barA.
A perfect vacuum is -1 barG or 0 barA.
That pressure gauge appears to be calibrated in barG, notice how the segments are equally spaced for the "bar" reading and the "inHG" marks don't line up with the segments. It also appears as though the gauge doesn't read higher than -0.025barG.
What pressure does the gauge read when it's not pulling vacuum? i.e. what does the gauge tell you is ambient pressure where you live? I would expect the indicator needle to be pressing hard against the white stop pin.
Edit, it took me a while to work this out...
The boiling point of water at -0.6barG is 170F, at -0.9barG it's 119F.
You're unlikely to boil the water out of the glue, unless its very hot where your working. There might be a potential to boil hydrocarbon solvents out of the glue if there's any in it. It be a good idea to keep an eye on the oil quality in the vacuum pump, you don't want to damage the pump.
Regards
Bob
That pressure indicator is reading "gauge pressure", not "absolute pressure".
At sea level, ambient pressure is 0 barG, or 1 barA.
A perfect vacuum is -1 barG or 0 barA.
That pressure gauge appears to be calibrated in barG, notice how the segments are equally spaced for the "bar" reading and the "inHG" marks don't line up with the segments. It also appears as though the gauge doesn't read higher than -0.025barG.
What pressure does the gauge read when it's not pulling vacuum? i.e. what does the gauge tell you is ambient pressure where you live? I would expect the indicator needle to be pressing hard against the white stop pin.
Edit, it took me a while to work this out...
The boiling point of water at -0.6barG is 170F, at -0.9barG it's 119F.
You're unlikely to boil the water out of the glue, unless its very hot where your working. There might be a potential to boil hydrocarbon solvents out of the glue if there's any in it. It be a good idea to keep an eye on the oil quality in the vacuum pump, you don't want to damage the pump.
Regards
Bob
Michael Kellough
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