Manometer
device · 1661 · Early modern era
An instrument that measures the pressure of a gas or liquid: a U-shaped tube of liquid or a Bourdon tube with a needle.
Principles and materials it uses
- Pressure — uses. Gas or liquid pressure pushes a column of liquid in a tube or straightens a Bourdon tube that moves a needle.
- Hydraulics (Pascal’s law) — uses. A liquid manometer is a pair of communicating vessels: the difference in levels shows the pressure.
Where it is used
- Boiler — is part of. The gauge on a boiler shows the steam pressure — without it the boiler could explode.
- Autoclave — is part of. The gauge shows whether the steam pressure in the chamber is high enough to sterilize.
- Blood pressure monitor — is part of. It shows the pressure.
History: what it evolved from and what it influenced
- Blood pressure monitor — evolved into. A blood pressure monitor is a manometer connected to a cuff: it measures the air pressure that squeezes the artery.
Things built in a similar way
- Barometer — works like. Both measure pressure with a column of liquid: a barometer measures the air around us, a manometer the pressure inside a vessel.