For you younger guys I just want to make it clear that it has nothing whatever to do with mamary glands. Hope is car related though. Dial says manometer and in large letters A lame Acier, Blondelles S.A. constructeurs. I assume the last is the maker. Reads to 6 bars on scale and has four threaded adapters plus misc. copper seals and rubber o rings in kit. Have not the foggiest ideal only remember manometer has something to do with fluids I thought. Just hoping has something to do with cars i guess. Someone gave it to my brother-in- law with no description some years ago.

Its used to measure air speed, a nice description of it is here:

http://www.science-house.org/student/bw/flight/manometer.html

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Thanks as was not even a good description in my dictionary other than measures liquid or gases. Have a start now. This device is in a plastic case very simular to what you find in specialized kits in for automotive service. Since it was six bars on total gauge sweep thought maybe oil pressure reading kit direct from block perhaps. No venturi effect on screw in adapters they are just threaded adapters to get you hooked up and kit is complete. It seems to have no provision incorporated in adapters to measure flow rate but just pressure. Thought it was perhaps for air conditioning but that did not particularily make sense to me either. Just a chinese puzzle I suppose.

Barry,

A manometer does not measure air speed. It measures vacuum. It is a tube that is bent in a u shape and filled with a liquid, usually either mercury or water and calibrated in inches of milimeters up both sides.

By connecting a rubber hose to one end of the tube and subjecting it to a vacuum it will cause the column of liquid to rise in that side of the tube. The height of the column is usually read in inches in the USA and in milimeters in the real world. This height will tell you the amount of vacuum. Vacuum is usually read in inches of mercury.

Conversly, applying pressure to one side of the tube will also give you a reading in inches of pressure.

A manometer is usually used to measure vacuum because the range of measure is usually smaller, i.e. less than 14.7 psi. Air conditioning people often use a manometer to determin air flow in the system or the pressure of natural gas at the heater.

Thanks again, will hook up to one of my vaccum sources and see whats happening on the gauge. Do think you fellows are right as cannot see it being mislabled. Expect heavy snow overnight here and may not be able to access and do for a couple of days. Now starting to suspect air conditioning may have been primary function after all. Too bad . Of course happen to own vaccum gauge already so may turn out as just surplus. Again best of the season. Oh yes, try to excuse my slow mental processes. Going to beg off with excuse of too much food indulgence in last two days. But really probably just thickheaded as usual. Hope to totally recover to semi-normal tomorrow, whatever that is.

Appears that there was a lot of good info in each post about the use and construction of manometers. However seems like all the answers covered what each person knew about a certain area of use. A Manometer is a U-tube filled with liquid that is used to measure pressure differences. The pressure difference can be between normal atmospheric pressure at the measuring point and a vacuum source, or one atmospheric pressure point and a slightly elevated one ( pressurized room ), or it can be the pressure drop across a furnace filter as it lints up. There were manometer type fuel gauges for mid thirties Auburns & Fords and engine oil level gauges on Auburns. The weather related barometric pressure was originally measured with a calibrated manometer. A manometer can be used to measure air speed but not directly. It would need to be hooked up to a calibrated pitot tube which creates a vacuum as the air flows thru it, then measured by the manometer. The liquid can be Mercury, water, oil, kerosine or really just about any suitable fluid as long as the temperature, fluid viscosity, and freezing point values are known and taken into account. Oh, and this is the real world!!! US of A!!!

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I think mercury is normally used in a manometer as it is about the heaviest material which is still a liquid at temperatures at which humans can live. Since it is so heavy, less of it can be used.

Gilly

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I have used manomometers to measure small amounts of air pressure. If you use water as the fluid, you can read very small pressures, or vacuum. An atmoshere of water is about 21-22feet. In a manomometer you can see 2 or INCHES of water column which is a very small fraction of an atmoshere. I used a manomometer to measure the air pressure in front of my Ford Pick up to see if there was enough pressure to "supercharge" the intake. ( The short answer is "no" . I found a max of less than 12" or half psi)
As a note of interest ( at least for me) Classically voiced pipe organs operate on 2 to 4 inches of water column.

A manometer is a gauge used to set multiple carburetors. Like the twin carb on English auto’s for the four carb’s on motorcycles. When each is drawing the same amount your Carb are “in Sync.”

Good point as I have one that totally covers each carb throat on my 1972 250c zenith carbs. Required me making up a round adapter plate to fit the zenith throat tops and believe the flow device i picked up years ago was for syncronization of multiple carbs. Measures the vaccum or airflow. Just get rid of all the airleaks around the bases of these carbs first. Famous for them I think. In fact when fooling around with these cars made my first meaningful discovery. Sometimes the carbs were gummed up. As these cars did not see service for many years. At least I keep them in heated storage. I did not enjoy the prospect or cost of removing manifold and carbs to clean and kit carbs. Kind of knew cars run well on laquer thinner. Also knew the thinner ate gas residue like crazy. Just took a quart can of it and separated fuel line at bottom of firewall. Ran engine till fuel was low in bowls and engine quit. Put hose in can and ran for a minute or so after getting thinner up in carbs. Let carbs soak, repeat again and carbs were cleaned like new. Sometimes had to change accelorator plunger but was probably bad or dryed out from sitting anyways. May have been the thinner dryed them out but just removing the leather ones and soaking in oil or leather conditioner may have restored them. Some were leather and some plastic if i remember. Best of all did not have to remove carbs to change part. Gas purge? I was sure other people used this approach but as time went on never heard or saw any mention of it. Sure worked for me and could find no downside at all. But only tremendous upside. Also very useful on our small motors like lawn tractors etc. In fact any gas engine that sit around unused a lot. Tuneup in a can at a dollar a quart? I actually got a thread started? Great, helps makes my season. Thanks.