tag:blogger.com,1999:blog-47352709372486088412024-03-12T19:33:06.595-07:00instrumentationthis blog is all about the calibration of instruments from temperature, flow, pressure and levelong-onghttp://www.blogger.com/profile/09173291947273581406noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-4735270937248608841.post-75568086217366184672010-07-12T06:56:00.002-07:002010-07-12T09:42:31.703-07:00pressure gauge calibration using deadweight tester<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhw_2kEq4GmOx8VZDJ5PpQdRBZNNHXnZc2jivStCQqatumSyMi1h49Zz_I3nDs8DJcVd4e-CuRg-0xaXHDQiAbH49WcLerfa1wGSmUOJZ2Iks1vkya2gtdyfq1sPd2Cw7MA6Me_9K7EHXY/s1600/DSC05855.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5493025749173203474" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhw_2kEq4GmOx8VZDJ5PpQdRBZNNHXnZc2jivStCQqatumSyMi1h49Zz_I3nDs8DJcVd4e-CuRg-0xaXHDQiAbH49WcLerfa1wGSmUOJZ2Iks1vkya2gtdyfq1sPd2Cw7MA6Me_9K7EHXY/s320/DSC05855.JPG" style="cursor: pointer; float: right; height: 240px; margin: 0pt 0pt 10px 10px; width: 320px;" /></a><br />
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STEPS:<br />
<br />
1. Set up the equipments needed for calibration<br />
note: know first the maximum capacity of the dead weight tester whether it can acommodate the range of the gauge calibrated.<br />
2. prepare the manual and date sheet that will be used for details of the instruments to be calibrated.<br />
some information needed for calibration to be input to data sheet:<br />
. equipment name/id no<br />
.ambient temperature<br />
. relative humidity<br />
.date of calibration<br />
.date of next calibration<br />
3. wrap the gauge fitting of teflon tape in clockwise direction<br />
4.place the gauge to be tested to the manifold assembly ( with gauge fitting match to the manifold joint) use correct size of wrench and make sure there is no leak.<br />
5. if the gauge has to be tested has for example 0 to 100 psi range, use the 5 points scale as reading reference.<br />
0% -low pressure ( zero reading)<br />
.100% high pressure<br />
(full scale reading)<br />
here are the i.e of 5 points calibration using zero to 100<br />
___________________________________________________<br />
[percent_____!___equivalent psi____!________________________________<br />
[___0%_____!____0____________!_____________________<br />
[___25%____!_____25__________!______________________<br />
[____50%___!____50___________!______________________________<br />
[____75%___!____75___________!_______________________<br />
[___100%___!____100__________!<br />
--------------------------------------------------------------------------------<br />
6. check the pointer intial reading 0 psi. If not, zero adjustment shall be made by adjusting the pinter zero.<br />
7.Place weights on the cylinder corresponding to each point scale of the pressure gauge. increase the actuating pressure equivalent to 0%, 25%,50%,75% and 100% of the assigned range<br />
8. Tightly close the release valve by turning clockwise.<br />
9.Pump gently until it weights floats to an ideal level<br />
10. rotate weights clockwise very gently and continuously while pumping.<br />
11.If cylinder base exceeds above or below the ideal level,, rotate fine pressure adjustment lever.<br />
12. record the pointer indication values for each point scale.<br />
.upscale ( o%,25%,50%,75% and 100%)<br />
.downscale ( 100%,75%,50%25% and 0%)<br />
this is the "as-found data".<br />
13. if the "as found" data exceeds the required accuracy, calibration should be done. a zero or span adjustment must be made.<br />
span = maximum range-minimum range<br />
14. repeat the procedure until the readings for each point scale is within the specified limits of accuracy.<br />
15.record the readings for each point scale and this is the as left date<br />
16. when done, release the built system pressure by opening the release valve<br />
17.put the calibrator sticker.<br />
18.make the calibration certificate with authorize signatures.<br />
19.housekeeping<br />
---------------<br />
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