M

Manometer

P = ρgh (hydrostatic); manometer measures pressure differential
Quick Reference
Formula / NotationP = ρgh (hydrostatic); manometer measures pressure differential
Also Known AsPressure gauge, U-tube manometer, differential pressure gauge, sphygmomanometer (blood pressure)

What is Manometer?

A device used to measure the pressure of a gas or liquid. Open-arm manometers measure gauge pressure relative to atmospheric pressure; closed-arm manometers measure absolute pressure. Mercury manometers use the height of a mercury column to indicate pressure.

Formula & Notation

P = ρgh (hydrostatic); manometer measures pressure differential

Other Names / Synonyms: Pressure gauge, U-tube manometer, differential pressure gauge, sphygmomanometer (blood pressure)

Properties & Characteristics

A manometer is an instrument for measuring gas pressure or pressure differences. The simplest type is the U-tube manometer filled with a liquid (mercury, oil, or water): the height difference between the two arms reflects the pressure difference. A closed-end manometer measures absolute gas pressure; an open-end manometer measures gauge pressure (relative to atmosphere). Digital pressure transducers have largely replaced mercury manometers in modern laboratories.

Uses & Applications

Manometers are used to measure: vacuum system pressures (during distillations, evacuations), pressures in gas reaction systems, blood pressure (sphygmomanometer), tire pressure, atmospheric pressure monitoring, and differential pressures across flow meters and filters in process equipment.

Safety Information

Mercury manometers contain toxic liquid mercury — mercury spills from broken manometers are a serious clean-up and health hazard (inhalation of Hg vapour). Use oil or water manometers, or digital pressure gauges, as safer alternatives. Mercury-free manometers are preferred in all new installations.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Manometer
Formula P = ρgh (hydrostatic); manometer measures pressure differential
Synonyms Pressure gauge, U-tube manometer, differential pressure gauge, sphygmomanometer (blood pressure)

Frequently Asked Questions

A device used to measure the pressure of a gas or liquid. Open-arm manometers measure gauge pressure relative to atmospheric pressure; closed-arm manometers measure absolute pressure. Mercury manometers use the height of a mercury column to indicate pressure.

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