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  1. #118
    Join Date
    Aug 2009
    Location
    Sugar Land, TX
    Posts
    56
    "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.

  2. #119
    Join Date
    Mar 2007
    Location
    wedged in freezer shelf
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    7,048
    Quote Originally Posted by chuckcrj View Post
    3/8 hose with schrader core removed. Yellow jacket black vacuum hose FWIW.
    Probably moisture in the oil then.
    Since using the BV its been taking longer since its a better gauge than I'm used to. I would have never seen stuff like that before unless it was dramatic.
    “If You Can Dodge A Wrench You Can Dodge A Ball”

  3. #120
    Join Date
    Mar 2007
    Location
    wedged in freezer shelf
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    7,048
    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”

  4. #121
    Join Date
    May 2008
    Location
    Texas
    Posts
    12
    Quote Originally Posted by dennyf View Post
    “Nice thing about the BluVac: it tells you that it is accurate. And if it is not, you can easily re-calibrate it (to factory specs) in the freezer. Try that with your YJ or JB.”

    Yeah, you’re right you would have to buy a new sensor and enter the calibration coefficient to get it back to factory calibration (it least for a YJ). So I know that you can calibrate the BluVac by putting it in the freezer and allowing it to warm to room temp; so it has a temperature to pressure relationship that you use to calibrate it. My question is that after performing the calibration as per instructions how does the microns displayed compare to a calibrated standard for values under 500 microns? If it is very close I know that I can use the BluVac to determine if my other vacuum gauge is working correctly. By the way I’m impressed with the BluVac you have a great tool. I may just end up with BluVac’s to check my main BluVac. Ha!
    FWIW, entering the 'offset' of the new thermistor is not the same as calibration; whether it is YJ, Thermal or J/B. The calibration procedure for the BluVac is the same they use in the factory for calibration; so the relationship of 'calibrated' values is the exact same (allowing for tolerances).

    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.

    BluVac wins...again.

  5. #122
    Join Date
    Aug 2009
    Location
    Sugar Land, TX
    Posts
    56
    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.

  6. #123
    Join Date
    Apr 2010
    Location
    Minnesota
    Posts
    520
    Any wholesalers carrying these yet? My boss isn't really excited about buying tools online with the old company card....

  7. #124
    Join Date
    Aug 2010
    Location
    Florida
    Posts
    250
    Quote Originally Posted by dunkman View Post
    Any wholesalers carrying these yet? My boss isn't really excited about buying tools online with the old company card....
    We are pushing real hard trying to get them into the traditional W/Ds, but, damn, its an up-hill climb. In this economy, few want to stock another new product, whatever it is.

    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.

  8. #125
    Join Date
    May 2008
    Location
    Texas
    Posts
    12
    Quote Originally Posted by dennyf View Post
    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)...
    That's my point, and I'm not arguing yours, I just want it to be clear for everyone. Simply installing a new sensor and 'adjusting' the meter to the new offset is NOT a calibration procedure.

    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!

  9. #126
    Join Date
    Aug 2010
    Location
    Florida
    Posts
    250
    Quote Originally Posted by dennyf View Post
    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.
    You would be surprised how much error can be contributed by the electronics. All of these gauges use the concept of "thermal conductivity" (TC) to estimate gas pressure, including the BluVac. Generally, heat is dissipated into the gas at a rate which is dependent upon both the TC of the gas, and the difference in temperature between the heating element and the gas itself. A mere 1 degree temperature error can result in as much as a 2.5% error in the micron reading under otherwise ideal circumstances.

    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.

  10. #127
    Join Date
    Jan 2008
    Location
    In the work truck
    Posts
    3,047
    Quote Originally Posted by dennyf View Post
    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.
    http://www.youtube.com/watch?v=G_6iOKzAuDA

    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.."

  11. #128
    Join Date
    Aug 2009
    Location
    Sugar Land, TX
    Posts
    56
    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.

  12. #129
    Join Date
    Jan 2008
    Location
    In the work truck
    Posts
    3,047
    Quote Originally Posted by dennyf View Post
    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.
    speak up. I'll make it happen..
    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.."

  13. #130
    Join Date
    Aug 2009
    Location
    Sugar Land, TX
    Posts
    56
    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.

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