How to Calibrate Pressure Gauges In-House

Sounds like you need a deadweight tester. Depending on the amount of gauges you are speaking of you may need a dedicated person as well.

Yes, a dead weight tester would be the perfect solution, however they are quite expensive. Another option would be to buy new gauges in the ranges that you use, and send these out for calibration. Label them "Standards", and don't let them leave your lab. Make up a test rig and periodically compare your field instruments to these.

Good idea, Bricktop, for practical application. It's very witty from position of common sense.

There are only two issues though. For one - is one completely legal, for two - from a classic metrological approach those "Standard" gauges should be matched at least 3 times higher accuracy class than field's ones. So it'd be turned out as the same pricey solution along with an ambiguous legacy.

Oh, I agree. Any method would have to depend on the level of accuracy required, and if traceability is required.

It is very difficult to give a "right" answer when the OP gives so little information to go on.

Yes, he will need Dead Weight Pressure Guage tester. The price will depend up on the accuracy we are looking for.

Standard pressure guage to compare will also be costly, as as you say it needs to be few orders high in accuracy than what acuracy we are looking for. Besides, this pressure guage needs to be calibrated and validated periodically from standard laboratory with international traceability.

Even if we keep in house DWPT, the instrument needs traceabilty and certification from accrediting authorities... its plunger diameter and the weights being used.

But, if we compare the two methods... DWPT and the calibrated high accuracy guage as standard, DWPT is better option, as it is less prone problems like going defective and getting calibration shift, as pressure guage may face. Besides, if you have number of guages to be calibrated periodically, this is the best choice.

The operation of DWPT is very simple. Need of dedicated person depends upon the number of guages to be calibrated (this will be needed even if you use standard high accuracy guage). Anybody wth little training can operate the DWPT.

Price will depend on pressure range and accuracy required but you might find something here: http://www.coleparmer.co.uk/catalog/product_view.asp?sku=6803500

Have a look at this thread, I was looking at a similar problem.

http://cr4.globalspec.com/thread/30836

You will find several dead weight testers for sale in Ebay, they have various ranges also most are not warranted. But generally speaking a dead weight tester produces the correct pressure with the weights supplied unless there is something seriously wrong with the equipment.

If you have to produce a warranted accuracy the equipment will have to be certified also you will need a clean room and an certified operator all approved by the relevant authority. If you are happy with in house tests to your own standard and not requiring public reliability there is no reason why a dead weight tester should not do the job.

If you are testing other than hydraulic gauges you will need an isolation testing chamber to avoid contaminating the gauges.

Hello, try this new product from GE Druck. Relatively inexpensive compared to a deadweight tester and the pressure modules are interchangable so you can alternate different ranges with the same basic set-up. The electronics also detach from the pressure simulation unit and can be used as a temp and electronic calibrator.

http://www.gesensing.com/products/amc.htm?bc=null

Full disclosure, I am a sales rep for this product in the US.

Ok, now lets get down to the "skinny", that machine costs what?

Take a look here, notice it say's "starting at":

http://www.instrumart.com/ProductList.aspx?CategoryID=734&Landing=1&gclid=CKmmw9bC2ZcCFQG7Ggode16L7A

Depending on the pressure range, saturated gasses, I'm thinking specifically of refrigerants have a known pressure at a temperature. the gas could be heated or cooled and it's pressure looked up on a TP chart. You would want to do this over a range of pressures.

It all depends on the requirement of the Gauges, If the gauges used for calibration (The masters) can not be traced to any of the standard laboratories, the calibration will not have any validity.

However for working gauges (not inspection gauges) this may not be a problem - unless the QMS/ OHSAS auditor objects.

I was looking at some sites, earlier, and had some interesting readings on solid state pressure gauges- of course piezo is ruled out (being dynamic), strain gauges may be OK and these normally have much more stability (and compensatable) for temperature etc changes.

check this site

www.sensorsmag.com/articles/1198/fun1198/main.shtml

it has some interesting readings

Welcome aboard! I'm guessing you are not in the United States, but just in case, for DWPT and also pressure testers with reference gauges (which can be used for calibration), try McMaster-Carr at < www.mcmaster.com >

The advice of the responses to use a dead weight tester is correct, however these "standards" have to be calibrated and THAT is very expensive. Your quality plan dictates how often gauges and standards have to be calibrated. The key is to determine what is reasonable and what guarantees that the gauges in use are accurate. If all your gauges are used for testing, the calibration should be yearly unless dropped or mishandled. If they are process gauges, they may need calibrated more often. In my plant our gauges are for testing vessels. We calibrate our gauges every year using a dead weight tester. We calibrate the dead weight tester every 10 years. It works for us. A combination of "standard" gauges, as suggested is good. Buy the dead weight tester, calibrated and write your plan so as to insure accuracy. It is reasonable to calibrate a dead weight tester every 10 years.

I often think the QA people are inadvertantly in the business of making sure the "Labs" have good cash flow.

I'm very happy to see all of you trying to help. In my company we use a "standard" gauge, (calibrated every year on a national laboratory) to calibrate pressure gauges installed on facilities and production equipment. With a precision of 0,01% full scale, we have an accuracy 10 times higher than the normal pressure gauges that we calibrate internally. We use a Keller LEX1 with a manual pressure pump (K/P Handpump). This system is very good to operate on field and it costs around 1300€ (cable and software included for data logging) I hope that this information can help. Best regards, Filipe Rocha Activeng, Lda

If you are looking for cheap, why not clean a porta-power pumping unit replace the oil with a mixture of glycerine and water tee that off to a calibrated test guage and the guage being set?

Thanks to all for replying my problem. I will Definately follow yours suggestions.

Yogesh.

Hi

in the past i faced same problem in our company so I asked for new eq. to make calibration for pressure gauges, Finally we bought a device from CRYSTAL ENGINEERING (search by google to find it)

the calibration method is too easy and try to read the manuls online.

Dear Yogesh,

You can buy the equipment can calibrate your gauges but will cost you for that equipment to purchase and you need to certify that equipment every year. How much is a cost to certify? where do you get certify your gauges. let me know i can get it done chipper or if you like to purchase the equipment i will sale to you. send me an emai at rakesh@gemcous.com, cell # 201-218-6930