Best way to measure suction and power?

Measurement of the suction draw of a vacuum (or carburetor vacuum lines) is done with a negative atmospheric pressure Manometer.

Positive pressure manometers are used for pipe organ chest, windtrunk and reservoir readings.

Originally conceived as a device showing graphic water level differentials in a vertical U shaped open ended tube and called 'water inches', later ones used mercury - mercury inches - as it did not evaporate and could be much smaller. I have a 1920s cast metal/glass tube water manometer that reads up to 10" for smaller organs, which normally use pressures of only 4-8" wind.

Since vacuums can pull up to 120 water inches a do-it-yourself water manometer would have to be at least that tall. Thus mercury manometers for large pipe organ work could be much more portable. I have a pipe organ mercury manometer tho the mercury fill is long gone.
Most vintage canister and cylinder vacuums pull from 50" to 65", with Compacts and Filter Queens easily reaching 75-80".

I don't recall the water to mercury conversion formula but any basic engineering book will.

Equally accurate and indisputably more portable are vacuum diaphragm dial gauges that use a brass can connected to a rotary needle. A single 1/8" nipple fitting open to atmosphere gives an needle-adjustable reading of 0". Tap this nipple to a rubber ball seals it against the vacuum inlet and gives the reading on the dial. These are made in all ranges of Automotive and industrial measurement and in the player piano hobby we all must have one at our bench that reads past 100".

A gauge like this is what is inside the fancy Vac-U-Tronic Tester. Through a hole in the side of the case one inserts the hose end against a rubber ball; I have a second rubber ball on a 3 foot rubber airline so I can bring the ball to the vacuum's inlet for considerately accurate readings, since hose coupler fittings tend to leak somewhat. The electrical measurement side of the vac-U-Tronic is isolated from and unconnected to the vacuum gauge. This is for controlling the on & off of the vacuum motor, checking the viability of various circuits and measuring amperage under load.
Picture of my Electrolux Golden J pulling 80".

This link goes to a Do-It-Yourself manometer page.

CLICK HERE TO GO TO aeoliandave's LINK


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Post# 127620 3/16/2011 at 02:22 (4,783 days old) by klectrolux ()
Checkrate/Likes What are some devices one could use to measure the suction and power of a vacuum? I know aeoliandave has a fancy device called 'Vac-U-Tronic tester', where would you find one or something similar to this? I do have a Kill-A-Watt device, but I don't think that's a good way to measure suction, just overall consumption of power. What other devices are there similar to the "Vac-U-Tronic" and where could you find one?

Post# 127626 , Reply# 1 3/16/2011 at 09:30 (4,782 days old) by Elux89 ()
Checkrate/Likes *Suction/Airflow gauge* To measure suction you can purchase a suction gauge giving you inches of water lift. To measures air flow, you can purchase a baird air flow meter. The baird air flow meter was primarily designed to be used with kirbys, but will work on most other applications. Any vac shop should be able to access one from their suppliers, or look on ebay. Hope this helps. Vernon

Post# 127668 , Reply# 2 3/16/2011 at 20:25 (4,782 days old) by roto-matic ()
Checkrate/Likes Yea, but is there any way to make those measurements with some homemade apparatus that you could just throw together with off the shelf parts? That's the kind of thing I'd like to know about. Then I could get a reading on my vacuum and show my parents how much stronger my 50 year old vacuum is to their new model. I remember Professor Julius Sumner Miller used to like to play with air rushing out of a nozzle on TV, demonstrating Bernoulli principle by crushing a big metal can. "Watch it, watch it..."

Post# 127681 , Reply# 3 3/16/2011 at 23:14 (4,782 days old) by aeoliandave (Stratford Ontario Canada)
Checkrate/Likes Measurement of the suction draw of a vacuum (or carburetor vacuum lines) is done with a negative atmospheric pressure Manometer. Positive pressure manometers are used for pipe organ chest, windtrunk and reservoir readings. Originally conceived as a device showing graphic water level differentials in a vertical U shaped open ended tube and called 'water inches', later ones used mercury - mercury inches - as it did not evaporate and could be much smaller. I have a 1920s cast metal/glass tube water manometer that reads up to 10" for smaller organs, which normally use pressures of only 4-8" wind. Since vacuums can pull up to 120 water inches a do-it-yourself water manometer would have to be at least that tall. Thus mercury manometers for large pipe organ work could be much more portable. I have a pipe organ mercury manometer tho the mercury fill is long gone. Most vintage canister and cylinder vacuums pull from 50" to 65", with Compacts and Filter Queens easily reaching 75-80". I don't recall the water to mercury conversion formula but any basic engineering book will. Equally accurate and indisputably more portable are vacuum diaphragm dial gauges that use a brass can connected to a rotary needle. A single 1/8" nipple fitting open to atmosphere gives an needle-adjustable reading of 0". Tap this nipple to a rubber ball seals it against the vacuum inlet and gives the reading on the dial. These are made in all ranges of Automotive and industrial measurement and in the player piano hobby we all must have one at our bench that reads past 100". A gauge like this is what is inside the fancy Vac-U-Tronic Tester. Through a hole in the side of the case one inserts the hose end against a rubber ball; I have a second rubber ball on a 3 foot rubber airline so I can bring the ball to the vacuum's inlet for considerately accurate readings, since hose coupler fittings tend to leak somewhat. The electrical measurement side of the vac-U-Tronic is isolated from and unconnected to the vacuum gauge. This is for controlling the on & off of the vacuum motor, checking the viability of various circuits and measuring amperage under load. Picture of my Electrolux Golden J pulling 80". This link goes to a Do-It-Yourself manometer page. CLICK HERE TO GO TO aeoliandave's LINK

Post# 127685 , Reply# 4 3/17/2011 at 00:47 (4,782 days old) by tolivac (Greenville,NC)
Checkrate/Likes Manometers-whether they be set up to measure pressure or vacuum-were also used in some physics labs.HVAC contractors may use them ,too.Usually such devices were more measuring pressures under 1 PSI.We have Manometers at the transmitter site for measuring the pressure of some of the transmitter main air blowers.They are useful to tell you when its time to change the air filters on the fan intackes-15Hp blowers. The VacUTronics vacuum cleaner tester would be useful today if the suction guage is updated to read more than 120"Some new vacuums-Meile,Riccar-can pull more than 120"I have seen them break guages that can't read over 120.I have a couple of these meters in vacuum cleaner sales kits-TriStar.And some Baird meters-Kirby.Baird meters measure CFM.I would think science lab supopliers such as Fisher-could supply manometers-as well as pipe organ parts suppliers.

Post# 127693 , Reply# 5 3/17/2011 at 08:49 (4,781 days old) by twocvbloke ()
Checkrate/Likes You need a water lift gauge like this: CLICK HERE TO GO TO twocvbloke's LINK on eBay

Post# 127699 , Reply# 6 3/17/2011 at 12:37 (4,781 days old) by klectrolux ()
Checkrate/Likes Thanks Dave for all the info, and the link to make my own. And then thanks to David/twocvbloke for the link to eBay. I hope I can find one off eBay similar to Daves for a decent price.