Which pressure gauge to use?

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JJG Koopmans
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Re: Which pressure gauge to use?

Post by JJG Koopmans » Mon Dec 02, 2019 10:14 am

Hi all,
The report of the Committee on Locomotive Front Ends of the Master Mechanics Ass. of 1906 is also on line:
https://babel.hathitrust.org/cgi/pt?id= ... up&seq=253
This shows the diminished performance of petticoats.
The other book of Goss is Locomotive Sparks, also online.
Kind regards

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Re: Which pressure gauge to use?

Post by rkcarguy » Mon Dec 02, 2019 3:00 pm

Glenn Brooks wrote:
Fri Nov 29, 2019 1:24 pm
As Richard says, you can get draft into the smoke box from the top of the stack! I just tested my exhaust out the stack and found 1/3rd of my stack drawing air INTO the smoke box (blower offset a little) on the port side of my engine. I used a long strip of paper. The exhaust sucked the paper into the smoke box on the one side- yet blasted it out of the nozzle on the other. A real eye opener. Now, I think this was due to nozzle placement. Both blast nozzles and the blower nozzle are catiwampus, offset to the rear and left of center in th stack.

Airflow tumble/reversal down part of the stack from the offset nozzle. Centering that alone will help quite a bit I bet.

Glenn Brooks
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Re: Which pressure gauge to use?

Post by Glenn Brooks » Tue Dec 03, 2019 2:36 am

Quick update on results of smoke box vacuum tests, using my home made manometer. I constructed the below seen nanometer last week and have made three trials with it thus far.

Briefly here are the results:

Test #1: 9” water in the gauge. 130# live steam feed from the boiler. no measurable reading from blower.

Device fell off loco during operation. Spilled the water out of the tube and disconnected from the smoke box fitting. Cancelled test.

Test #2: 9” water in gauge. stationary. 120 lbs live steam from boiler. Blower only, 9” water in the gauge. no measurable vacuum.

Test #3: 4” water in gauge. stationary. 100 lbs compressed air feed to blower. consistently measured 5/16” vacuum with lower water level in gauge portion of the device.

For test 3, I centered the blower nozzle on to the axis of the stack. This corrected the negative pressure and air flow out of the port side of the stack- resulting in a noticeably more consistent air flow at the exit. This very likely contributed to increased and measurable vacuum.

Note: Also inclined the gauge to approx 45* angle for one iteration during test # 3. At the inclined position, Vacuum reading showed 6” water movement in the gauge. Then when vertically mounted, during next iteration, again 5/16” water vacuum.

I suspect the weight and resistance in the tube of 4”+ column of water is to great for the existing vacuum capacity in the smoke box to create a measurable reading. The lower weight, volume, and resistance of the 4” of water in the gauge appears to render the Manometer more useful for measuring smaller vacua.
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Motive power : 1902 A.S.Campbell 4-4-0 American - 12 5/8" gauge, 1955 Ottaway 4-4-0 American 12" gauge

Ahaha, Retirement: the good life - drifting endlessly on a Sea of projects....

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Re: Which pressure gauge to use?

Post by NP317 » Tue Dec 03, 2019 11:23 am

Keep going.

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