What Is Hg Vacuum

Hg Vacuum

What Is Hg Vacuum? By measuring manifold pressure, vacuum gauges are used to identify engine faults. Anything that is below atmospheric pressure is referred to as a vacuum, and a reading of 0 Hg is equal to atmospheric pressure. The measurements (in inches or millimeters of mercury) demonstrate the ability of a vacuum to hold mercury in a tube at a height equal to whatever is being measured. Mercury is a metal with the symbol Hg on the periodic table of elements. Although achieving a genuinely perfect vacuum is impossible, thirty inches of mercury is considered an effective perfect vacuum. Higher vacuum gauge readings usually indicate a healthier engine.

What Is A Vacuum Pressure 

The force deliver over an area, such as the wall of a container or as part of a manufacturing process, is known as pressure. The pound per square inch, or psi, is the most common English unit for pressure. See the conversion table to convert psi to other units.

How Vacuums Are Measure In Hg Vacuum

The number of molecules in a chamber determines the vacuum level. There are a variety of vacuum measurement units available; some of the most common are:

  • in.-Hg – this unit of measure refers to the height of a mercury column in inches. It is useful for estimating vacuum levels. It is a measurement that differs from the atmosphere and is usually express as a negative number.
  • Mm.
  • -Hg – refers to the height of a mercury column in millimeters, as well as the = Torr. It is differential pressure from the atmosphere when stated with a negative. It is an absolute measure when expressed as a positive number.
  • Torr is equal to 1/760 of an atmosphere, or 1 millimeter.
  • -Hg When expressed as a positive number, this is the same as mm Hg.
  • Atmospheres – 14.7 psi is one standard atmosphere of pressure (pounds per square inch)

What Is mmHg In Vacuum Pressure

We usually talk about gauge pressure, which is the pressure above atmospheric (or barometer) pressure.

At sea level, atmospheric pressure is specified to be 14.7 psi, 101 kPa, 760 mm Hg, and 29.92 in Hg. All of these values are equal in different unit systems.

Gauge pressure plus atmospheric pressure equals absolute pressure relative to a perfect vacuum of 100 percent.

A partial vacuum is define as negative gauge pressure. As an example, a vacuum of -5 inches of mercury may be written as:

(-5 in Hg) +29.92 in Hg Absolute Pressure

in Hg Abs = 24.92

Moreover, this assumes that your barometer is set to 29.92 inches of mercury.

Alternatively, we can use a compound gauge.

How Vacuum Pressure Is Calculate

can calculate Vacuum pressure in different ways. Some of them are as follows

Pressure Gauge In Hg Vacuum

Gauge pressure refers to the pressure measure concerning the surrounding atmosphere (approximately 14.7 PSIA). PSIG (pounds per square inch (gauge)) is the abbreviation for this measurement. At 0 PSIG (14.7 PSIA), a gauge pressure transducer’s electrical output is 0 VDC, and at full-scale pressure, it’s full-scale output (usually 5 VDC) (in PSIG).

Absolute Pressure

The measurement of absolute pressure is concerning a high vacuum (0 PSIA). PSIA (pounds per square inch) is the abbreviation for pounds per square inch (absolute). An absolute pressure transducer’s electrical output is 0 VDC at 0 PSIA and full-scale output (usually 5 VDC) at full-scale pressure (in PSIA).

Vacuum can refer to any pressure between 0 and 14.7 PSIA. At last it must be defined further. Two methodologies are frequently use in situations involving monitoring vacuum pressures over this entire range.

Vacuum Setra’s Sensors In Hg Vacuum

Vacuum pressure transducers from Serta with capacitive sensing technology and can be utilize in various applications. Setra’s Model 206, 209, and 210 are accurate, reliable, and steady and have been effectively integrate into applications ranging from injection molding to semiconductor manufacturing. The AXD is the newest member of this product family, and it’s design to be a tough solution for the toughest applications.


The difference in pressure between pressure in the evacuate system and atmospheric pressure is known as the vacuum level:

760 torr = 14.7 psia = 29.92 inc mercury abs = 101.4 kPa abs = 0 percent vacuum

380 torr = 7.3 psia = 15 inc mercury abs = 50.8 kPa abs = 50% vacuum

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