Hi there everyone!
Welcome back to Cody's Lab
So I have a new little toy which is paid for by my Patreon supporters
Let's have a little closer look at that
You see it's a vacuum gauge
This is a thermoeletric type so it shouldn't matter that it's actually inside the chamber
Cause all it is, is it's a heater and a temperature detector thermometer
So it's got a heater and a thermometer
And they measure the temperature difference between the two
To estimate what the - uh - you know how conductive the medium is
If the medium's a perfect vacuum it shouldn't be conductive of heat
At all except for the radiation
And I assume it's very well calibrated because it's a very expensive device
And uh
Yeah and I was getting at that it shouldn't matter that it's actually inside the chamber
'Cause it really makes no difference to it
'Cause as long as the internal parts of it are evacuated it'll work just fine
So uh
My mercury gauge just up there
Has started to read a low pressure
And uh this one
It should've started reading a pressure but it just probably hasn't uh
Reached a temperature differential yet so it probably still thinks it's in an atmosphere
So I'll wait a little while and see if it actually starts reading
It's uh one thing I like about the mercury gauge is it's immediate and you easily can see it
But uh
This ought to be a good calibration test to see just how incorrect my mergury gauge is
Uh the mercury gauge
Uhm
I'd say it's probably plus or minus two millimetres of mercury
Because uh
There's a little bit of cohesion with the glass and the mercury
So it, it'll actually hang up a little bit so you're not getting a true reading
But I've been uh, taking into that
I've been taking that into account in
Most of my videos, I don't think I did in a couple
But uh
This is taking a long time I think it shoulda responded faster than this
I'll give it another few minutes
Which uh
Is kind of
Not good because according to the specification sheet, that I got here
The thing'll shut itself off after 5 minutes of inactivity, so
If it takes more than 5 minutes to reach the vacuum then
Or, or start reading the vacuum, then it's absolutely no good to me
Well
I'm gonna pause the video, I'll come back if it starts doing anything
Okay so it has started to do something
You can see that little bar is now
On the bottom row
That means that it's measuring between 50,000 and 25,000 microns and
There it is, now it's uh below 25,000 and it's reading a number
Course 25,000 microns is
25 millimetres of mercury so
Wrong at the moment but it should
Uh, hopefully reach a point where it's actually correct so, once it stops falling
Well, Imagine that'll be
The actual reading
If it doesn't manage to do it I'm just gonna send the thing back
Well, either that or I'll
Get a different vacuum chamber and
Actually have a port on the outside that I can plug it into
That way I can - or, or maybe even make like an automatic button pusher, like every
four minutes just restart the device
Don't know if that would actually be good for it
Alright now it's reading about the same as what the mercury gauge is reading
I expected it to go down a little bit farther
So the gauge appears to have reached a point where it's stopped decreasing
It's number that it's givin' me
It's kinda bouncing back and forth
And uh apparently, according to it's specifications it should uh
Be plus or minus 10% of the actual value
So that's
It seems reasonable to me
So that's three and a half millimetres of mercury
And that probably indicates that I've got a bit of a leak in my chamber or
Actually more probably I need to replace my vacuum oil
But uh
Yeah, that's uh
'Bout 4 mil-
4 - 5 millimetres on the uh
Mercury gauge
3 and a half-ish on the
Precision
Vacrometer
I'd say those two
Match fairly closely
And it turned off
Ha ha
Hold I caught that just as it was doing it
I was just about to say that uh it didn't turn off after the 5 minutes but
Turns out it did
Yep
Okay
So it does turn off
Even when it's under vacuum and
Doin' things
That's annoying
Like what if my thing is lasting longer than that
Obviously it was designed to be outside the chamber
And just hooked up to it
If you guys uh
Have this unit and know how to fix that let me know
Otherwise I might have to [gear rig?] something or possibly even send it back
'Cause I'd like to run it inside the chamber so I could have it on screen with ya
'Spose I could hook it up into the vacuum pump but
Then you won't be able to see it
On camera
Well I guess I could move the camera but *laughs*
Alright
Well
I was gonna do a test where I unplug the vacuum pump and see how fast the pressure comes back but
It doesn't look like it's happening so
Hope you all enjoyed, I'll see you next time