TUSA SPG measuring wrong

[emoreira]

4 years ago I bought a TUSA Platima SPG.
Today I was complaining of the low pressure a gas tank was filled by the LDS, and my buddy told me that his tank was 2800 and both were filled in parallel, so there was no reason why my tank was 2500.
We changed regulators and his tank was now 2500 and mine was 2800, meaning that my SPG measures wrong.
Is there a way to calibrate my SPG ?

 

[redacted]

Your memory or a permanent magic marker. I don't worry much about small high end errors. But do take a close look at the low end.

 

[tbone1004]

unfortunately not. Time for a new SPG, they do wear out over time, especially if they get pressurized real fast regularly, better to ease them into the pressure. SPG's are cheap and you can reuse the hose.

What happens when they start reading low like that is that the spring is stretched and that makes it inaccurate throughout the whole range, no amount of calibration can fix that on an analog gauge. It's 300psi low at 2800, but it may be 600psi low at 1000, so there's no way to fix it.

 

[LandonL]

Honestly, getting a new gauge is your only option to 'fix' the situation.

You could memorize a few actual values versus what your gauge is showing by using another more accurate SPG to determine different pressures, but by far the easiest method is to just buy a new SPG. They are not really that expensive anyway.

 

[JohnN]

unfortunately not. Time for a new SPG, they do wear out over time, especially if they get pressurized real fast regularly, better to ease them into the pressure. SPG's are cheap and you can reuse the hose.

What happens when they start reading low like that is that the spring is stretched and that makes it inaccurate throughout the whole range, no amount of calibration can fix that on an analog gauge. It's 300psi low at 2800, but it may be 600psi low at 1000, so there's no way to fix it.

I thought the spring in a Bourdon gauge only pre-loaded the needle?

 

[tbone1004]

it does, but explaining the bourdon tube like a spring is easier to understand. What is most likely happening is stress hardening of the curl in the bourdon tube due to rapid pressurization which is making it less sensitive to pressure changes.

 

[divad]

4 years ago I bought a TUSA Platima SPG.
Today I was complaining of the low pressure a gas tank was filled by the LDS, and my buddy told me that his tank was 2800 and both were filled in parallel, so there was no reason why my tank was 2500.
We changed regulators and his tank was now 2500 and mine was 2800, meaning that my SPG measures wrong.

How do you know your buddy's gauge is not reading high?



Here's a nifty picture:

 

[tbone1004]

quick explanation.

when the gauge gets pressurized, the bourdon tube *the silver pipe looking thing* expands causing the top bar to lift up which pulls on the brass arm which then causes the needle to go up.

Possible his is reading high, would go to the LDS and crosscheck it against one of their pressure gauges to make sure you pick the right one that needs to be replaced