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Thread: AccuTools BluVac Micron Gauge
06-28-2011, 11:05 PM #118
"What are u pulling the vac on? Hopefully not just the gauge itself,cuz that is not telling you anything. "
It's telling me that my vacuum pump is working and the oil doesn't need to be changed. I also do a test with a 30lb recovery cylinder to see how long my pump takes to 500, 200, 100 etc mics.
06-29-2011, 08:04 AM #119
06-29-2011, 08:06 AM #120
Was cleaning in the garage and found a 9V transformer with +/- plug and am just connecting the BV with the pump now.“If You Can Dodge A Wrench You Can Dodge A Ball”
07-01-2011, 09:20 PM #121Regular Guest
- Join Date
- May 2008
YJ doesn't even publish the calibration procedure for their vacuum gauges; but they are not unique in that respect...
Thermal Engineering does though:
Thermal 14571...Calibration Procedure
As you can see, just entering the 'offset' on a Thermal Vacuum Gauge isn't the same as calibration. If it is not calibrated the new sensor will still be incorrect after the offset is entered.
07-01-2011, 11:29 PM #122
I agree that the BluVac method of calibration is more complete and is the way they do it at the factory. However, when YJ, JB or whoever provides you with a calibration coefficient (offset) they are calibrating the sensor to a know standard. They are not taking into account the offsets, drift etc. of the electronics in your meter, but the error contributed by the electronics is minuscule compared to an un-calibrated sensor. So in effect it’s about as close are you are going to come to factory calibration (I not sure if YJ, JB calibrate the whole package or just the sensor). By the way I like the way the BluVac lets you calibrate the same way as the factory. I would like to compare it to several other know accurate Vacuum gauges before I declare it the standard by which all other vacuum gauges are compared. So far I really like it and have confidence in it.
07-01-2011, 11:32 PM #123
Any wholesalers carrying these yet? My boss isn't really excited about buying tools online with the old company card....
07-01-2011, 11:53 PM #124
For the time being, TruTechTools.com is the only place to get it. If your boss doesn't want to deal with them, call us and maybe we can work something out.
07-02-2011, 12:20 AM #125Regular Guest
- Join Date
- May 2008
True, the new sensors are calibrated (and subsequently stamped) to a known reference (500 microns or whatever) but also to a known electrical reference (that's the stamped number reference). The reference is in their lab (or whoever they source it from), not your instrument. If you KNOW your instrument is as accurate as their bench reference then you have no need for calibration; slap on a new sensor and go... My point is, we don't KNOW that to be true, hence the need for calibration (REAL calibration).
IE, the Thermal Instrument is designed to read 500 Microns at 37 mA, the YJ is very similar. IF it is out of calibration and reads 500 Microns at 45 mA then it doesn't matter how many new sensors you put on it and 'offset'; they will all be inaccurate (but still SHOW 500 microns!). So you THINK you are at 500 microns but in reality you aren't.
The drift in the meter you say is miniscule is the very transient we are eliminating when we calibrate an instrument. But you are right again in that installing a new sensor is about as close as you are going to get to factory 'calibration'...with the YJ. The BluVac, on the other hand, is EXACTLY to factory calibration; there are no unknowns.
YJ, J/B and Thermal do calibrate the whole instrument; otherwise they would be useless to us.
The point is this; when you calibrate a BluVac you are REALLY calibrating the instrument. It isn't just an offset for a new sensor. There are only two ways to know if it (anything) truly is in calibration; calibrate it like the factory does or, measure it against a known reference.
I also agree that the sensor is the weak link and is, most often, the source of errors. However, in speaking of calibration, you either know or you don't know; I want to KNOW!
07-02-2011, 12:29 AM #126
Even with the best precision temperature sensors, it is not easy (or cheap) to get better than 1 degree accuracy across a broad range of operating temps. Part of the magic of the BluVac is that it essentially eliminates temperature errors as a factor in the pressure computation.
As a case in point, many micron gauges are spec'd to be accurate only within a limited temperature range, and, in fact, are calibrated (at the factory) at that particular temperature. Further, some only guarantee accuracy within a small range of pressures at that temperature.
Finally, the "calibration coefficient" that you refer to is a "one-dimensional" value. It can only compensate for a single variation among sensors, whether it be an offset or a scaling value, and only applicable at the time-of-manufacture of the sensor. What happens if the sensor changes as it ages? Is that coefficient still valid? How do you know? The BluVac recomputes all of its own coefficients during the calibration process, ensuring that even an aged sensor can be operated as accurately as the day it left the factory.
Listen, I know this all sounds like hocus-pocus and typical marketing speak. I'll be the first to admit that when I came up with the idea for the BluVac tech that it was based upon a bunch of unwarranted (but logical) assumptions. I knew it would work, but I didn't know how well. Only after I started testing actual hardware did I begin to understand how well it did work, and, believe it or not, I was in stunned disbelief at how well it did work.
07-02-2011, 09:43 AM #127
did you watch this?
The bluvac is it. It is way more responsive then the others..
THe thermal usually compared well in other tests but this time it was out in left field. After I brought the system up to atmosphere it was back on track..
I did not experience those type of issues with the bluvac.Gotta have the right tool for the job!
Where is all the stuff MADE IN THE USA?
"Thats what we do Troy. Incredible, Invisible, Imbelivable things. We are an Unseen, Unknown, Unvincible fraternity of craftsman.."
07-02-2011, 09:56 AM #128
Yes, I did watch that video; that is one of the reasons I bought the BluVac. However, even though the vacuum gauges are connected to the same system, If you are comparing two I would like to see both connected on the same pipe, preferably with a tee so they are both reading the same environment.
07-02-2011, 09:59 AM #129
07-02-2011, 10:17 AM #130
Great! By the way I appreciate your taking the time to share your test results with us. That why I wanted to share my results too! It helps all of us make informed decisions when in comes to purchasing equipment.