how to determine volume of hidden vessel

A23s are oddball batteries, which I've bought only once locally. I have had to both bend the clips and tape the battery in for each of my wireless doorbell transmitters over the years.

The Chiwanese brands give over a year's service for under a buck apiece in a 5pk. Free shipping from Chiwan takes 4-6 weeks.

Duracells $3 a pop in 2pks gave a bit more: 1.5 years.

Energizers at $6 a pop in 2pks give zero life, since I won't pay that ridiculous price.

Back in grad school, I screwed up the conversion of Pascals to atmospheres (or Torr?) by a factor of ten. And made my flow impedance line x10 times too restrictive. ~x10 the work too. But once I found the mistake in my notebook it was pretty easy to cut the line down to the right impedance.

George H.

Nice find. Ordered one last night.

My house is now at 22C so as promised I rechecked theAD584 reference against the 5-1/2 digit Fluke, after an hour warmup which decreased the Fluke's initial 11 microVolt zero offset to +/-0. Using an analog variable power supply, the Fluke reads +10.0018/19 with 12V powering the standard, and +10.0021/22 with 18V powering it. It starts to droop below 10.0018 at less than 11.0V in.

I'd say that a more convenient 12V A23 battery clipped onto the board is fine for adjusting 3-1/2 and 4-1/2 digit DVMs and the AD584 only benefits from two dangling 9V batteries with a 5-1/2 digit meter. Up to 30V is permitted. At 27V the Fluke still reads +10.0021/22, but lingers longer on 22.

-jsw

I got one of these boards. Hooked it up just now to a bench supply at 15V. I checked one of my three Fluke 8840As that hadn't been calibrated in over 20 years. Holy crap dead nuts on target. Fluke builds some serious stuff.

And, for giggles, the Centech POS they were giving away at HF reads: 2.49, 4.99, 7.48, 9.98. Not nearly as bad as I expected.

Later, I'll check some more meters. But so far, I'm happy that I got the reference board, it confirms that my "reference" meter can still be trusted, and I needn't pay for calibration unless a particular job demands it.

skating rink, and we have decided to replace the R22 with RS-45 as part of a general upgrade. The system was full of leaks and was constantly losing s ignificant and costly amounts of R22.

h the pipes under the ice surface. These pipes are buried in concrete and n obody knows how large they are. The people who installed this are long gon e, and there is zero access to the piping after the large feed and return l ines enter the concrete.

imates ranging from 4000 pounds to 7000 pounds from various experts in the field. That extra 3000 pounds is almost $30,000, so it would be good to get a better feel for a real number. The refrigerant pipes in a typical rink a re about 10 or 11 miles long (seriously), and are (sometimes) 5/8 OD thinwa ll steel, but that's a variable.

covered really has no bearing on the actual capacity as there had been cons iderable leakage.

I can isolate the rink floor pipes from the rest of the system and there ar e service valves accessible, does anyone know how I might determine the vol ume of these pipes?

rate and watching for a pressure rise and then doing some magic calculation s I haven't thought about since high school. Does that make sense? can anyo ne offer specifics?

Crap - every time I try to get started on this, another emergency comes up. I did pump ump with air, and found a couple more leaks. Hopefully, this we ekend I'll get to do the actual test.

All the yellow and red HF meters I have can be adjusted, though the pot is overly sensitive.

-jsw

Probably, but not really worth the trouble to get one more least significant digit. It's close enough to live in my glove compartment.

I use them for battery testing where the full range from charged to discharged is 1V or less, on the 20V range, and the second decimal place is reassurance that the first one is correct. Accidents do happen so I wear safety glasses and don't risk my better meters.