The Instrumentation for Measuring Vacuum

The word “vacuum” comes from the Latin word meaning empty or void, in science vacuum refers to a space that is low in pressure than the pressure in the atmosphere. It is a condition that is well below the atmospheric pressure and is usually measured in Pascal which is known to be the units of pressure. There are two types of vacuum, the partial vacuum in which some low amount of matter is there and then there is the absolute vacuum in which there is no matter, the absolute vacuum is also known as free space.

Measuring Vacuum With Instruments

The measuring of the vacuum is quite necessary and it is done by the vacuum instrumentation, there are quite a lot of instruments that are used to measure vacuum out of which gauges are used the most and are quite popularly used. What is a vacuum gauge? A vacuum gauge is a gauge that is mainly used for the purpose of measuring pressure and it is set in negative values at the zero points. The gauges are designed in a way that they vary in design depending upon the range of the vacuum:

1. The hydrostatic gauges -  The instruments for measuring the emptiness of a place are being used for centuries, there are the type of hydrostatic measuring devices the bourdon gauge and the McLeod gauge. The Bourdon gauge is also known as the diaphragm gauge which is known for accurately indicates the pressure. The McLeod gauge can measure absolute pressure quite accurately and the best thing about this gauge is that it is not affected by the gas that is there in the system.

2. The capacitance manometer gauge - This is a pressure gauge that is used for the measuring of vacuum, the higher the vacuum would be the father would its diaphragm go. The main advantage of using a capacitance manometer gauge is that has the ability and the quality of detecting diaphragm movements that are extremely small. The accuracy of this instrument is also high; it is mainly used in the semiconductor industry for corrosive services.

3. The Pirani gauges - The Pirani gauge is used to measure the pressure in a vacuum, there are two types of such gauges the constant current and the constant resistance. Each of the Pirani gauges mainly sees the electrical measurement of the wire.

4. Thermocouple gauges - The Thermocouple gauges are similar to the Pirani gauges and the current in this is mainly determined by the resistance. This kind of gauge is mainly used for comparing and the sensitivity of this gauge is based on the pressure as well as on the strength of the current. One disadvantage of this gauge is that it has no linear order marked, meaning that at high pressure the markings are quite close while in low pressures the markings are quite apart.

5. Ionization gauges - Most of the modern furnaces rely on the ionization gauges, these gauges are able to detect pressure indirectly by just measuring the electrical ions. There are two types of ionization gauges the hot gauge ionization gauge in which three electrodes are used are most commonly used today and then there is the cold cathode gauge, in which the pressure is measured by a gas discharge which is at low pressure.

Conclusion

So, different types of vacuum instrumentation are basically used to measure everyday pressures in the unit of pressure. All these instruments are used to measure varied kind of pressure to a person using a gauge should be well aware of the atmospheric pressure level the instrument can record.