testing 0.25 in water manometer

[paulmars]

I need to test this gauge. It reads -0.25 to 0 to +0.25 in water. Im using it in the 0.02 to 0.03 negative and positive ranges. What of known value can I use to deflect this gauge maybe .1 or .05 in either or both directions to test the gauges accuracy?

pa

 

[paulmars]

mount it inclined 10:1 for 10 times the resolution. https://www.amazon.com/Yellow-Jacket-78075-Water-Manometer/dp/B0038QHTK2/ref=sr_1_5?ie=UTF8&qid=1520466840&sr=8-5&keywords=manometer

its graduated at 0.25 intervals and you can easily judge 1/5 of that. So, 0.25 included 10:1 the 0.25 would then be 0.025 and I could fairly accurately judge 1/5 of that or 0.005.

thoughts?

 

[John Cuthber]

Something like this

https://www.coleparmer.com/i/dwyer-mark-ii-25-inclined-manometer-3-wc/6806258

though you may wish to make, rather than buy, one.

[paulmars]

3 hours ago, John Cuthber said:

Something like this

https://www.coleparmer.com/i/dwyer-mark-ii-25-inclined-manometer-3-wc/6806258

 

stated accuracy of that dwyer is +/-0.09 which makes it less then useless.

[John Cuthber]

3 hours ago, John Cuthber said:

though you may wish to make, rather than buy, one.

 

[paulmars]

then how would i test its accuracy?

[John Cuthber]

Make 2 or 3 and see how well they agree.