If you are finding the list of pressure measuring device then you are at right place. Here will show the detailed function of all pressure measuring devices. We will also see the working and operating principle of pressure measuring device also. Here we will see different types of pressure measurement instrument.
Pressure is an expression of the force required to stop a fluid from expanding and is usually stated in terms of force per unit area. A pressure sensor is a device for pressure measurement of gases or liquids. A pressure sensor usually acts as a transducer; it generates a signal as a function of the pressure imposed.
Pressure is defined as the force per unit area : P = Force(F) / Area(A)
Pressure plays an important role in determining the boiling points of different liquids.
List of pressure measuring devices:
For measuring pressure different transducers are used. Electric pressure transducer translates mechanical force to the electrical signal such as the Bourdon tube, bellow, and diaphragm. You can also be called the types of the pressure transducer. Here is the list of pressure measuring device ( pressure transducer ) :
1. Elastic pressure transducer
- Bourdon tube pressure gauge
- Bellows pressure gauge,
- Diaphragm pressure gauge
- Manometer method: manometer
- Vacuum pressure measurement device
- Pressure measurement by balancing forces produced on the known area by a measured force
Direct Methods for measuring pressure: Here the displacement deflection caused by the pressure is measured and is correlated to the pressure. The following devices are included in this category:
>> Spiral Bourdon tubes
>> Flat and Corrugated diaphragms
Indirect or inferential methods: In these methods, a pressure is determined through the measurement of certain other pressure controlled properties, including volume and thermal conductivity. Devices included in this category are:
>> Mcleod Gauge
>> Thermal conductivity gauges
>> Ionization gauges
>> Radioactive vacuum meters
So we are going to know all pressure measuring devices (pressure transducer) in details one by one.
Elastic pressure transducer
These pressure transducers are used in high-pressure measuring applications. Most pressure measuring devices use elastic members for sensing pressure at the primary stage. These elastic members are of many types and convert the pressure into mechanical displacement which is later converted into an electrical form using a secondary transducer.
Elastic pressure transducers are :
>> Bourdon tube pressure gauge
>> Bellows pressure gauge
>> Diaphragm pressure gauge
Let see in details for this pressure gauges.
Bourdon tube pressure gauge
The bourdon tube works on a simple principle that a bent tube will change its shape.
As pressure is applied internally, the tube straightens and returns to its original form when the pressure is released. The tip of the tube moves with the internal pressure change and is easily converted with a pointer onto a scale. Generally, c shape bourdon gauges are used for measuring pressure.
Bourdon tubes are generally available in three types. Types of bourdon tube are,
>> C shape burden tube
>> Spiral type burden tube
>> Helical type burden tube
Spiral type bourdon tubes
The spiral Bourdon tube makes a few windings in one plane around the fixed shaft of the pointer. When the tube is being uncoiled by the process pressure, the free end will have a larger displacement compared to the C-shaped tube. The more windings, the larger the displacement will be.
For low-pressure ranges, the spiral is made of a flat oval tube, while the round tube is being used for the high-pressure ranges. The same low pressures can be measured with the spiral Bourdon tube as with the C-shaped Bourdon tube but the cost for a spiral pressure gauge is higher.
Helical type Bourdon tube
The helical Bourdon tube has several turns winded into a helix.
The number of coils can vary from two or three to as many as twenty.
They can be equipped with or without a transmission mechanism. With 2 to 3 windings, the measuring range will rather be small and a transmission mechanism will be necessary to amplify the movement of the free end.
Having 16 to 20 windings, a larger measuring range becomes possible without the need for a transmission mechanism because the movement of the free end is large enough on itself.
ADVANTAGES of the bourdon tube
- Wide operating range
- Fast response
- Good sensitivity
- Direct pressure measurements
DISADVANTAGES of the bourdon tube
- Sensitive to temperature variations
- Limited life when subjected to shock and vibrations
Now we will see another pressure measuring device diaphragm pressure gauge.
Diaphragm pressure gauge
The diaphragm is a flexible disc, which can be either flat or with concentric corrugations and is made from sheet metal with high tolerance dimensions.
The diaphragm can be used as a means of isolating the process fluids, or for high-pressure applications.
It is also useful in providing pressure measurement with electrical transducers (LVDT).
Diaphragm pressure gauge is used as primary pressure transducers in many dynamic pressure measuring devices.
Corrugated designs help in providing a linear deflection and also increase the member strength. The total amount of deflection for a given pressure differential is known by the following factors
- Number and depth of corrugation
- Number of capsules
- Capsule diameter
- Shell thickness
- Material characteristics
Advantages of diaphragm pressure gauge
- Good for low pressure
- Wide range
- Reliable and proven
- Used to measure gauge, atmospheric and
- differential pressure
Bellows pressure gauge
A bellows pressure gauge contains an elastic element that is a convoluted unit that expands and contracts axially with change in pressure.
The pressure to be measured can be applied to the outside or inside of the bellows. however, in practice, most bellows measuring devices have the pressure applied to the outside of the bellows.
Other types of pressure transducer:
We can also classify transducer based on their working and material used. Here are some types of pressure transducer :
- Resistance type pressure Transducers
- Pressure Voltage type
- Capacitive Type
- Carbon pile type
- Piezoelectric type
- Photoelectric Type
- Electromagnetic Type
Resistance type pressure Transducer
Resistance type pressure transducer are,
>> Strain gauge pressure transducer
>> Moving coil pressure transducer
Now here we know in details about strain gauge pressure transducer. Here we know strain gauge pressure transducer working principle, construction, and working of strain gauge pressure transducer.
Strain gauge pressure transducer
When a strain gauge, is used to measure the deflection of an elastic diaphragm or Bourdon tube, it becomes a component in a pressure transducer.
Strain gauge-type pressure transducers are widely used. The strain gauge is used to measure the displacement of an elastic diaphragm due to a difference in pressure across the diaphragm. These devices can detect gauge pressure if the low-pressure port is left open to the atmosphere or differential pressure if connected to two process pressures.
Stain gauge pressure transducer is used for narrow pressure span and for differential pressure measurement.
Hope you find your list of the pressure measurement devices. Here we show which transducers are used for pressure measurement. Here we saw a different pressure gauge for measuring mechanical pressure. Bourdon tube pressure gauge, Bellows pressure gauge, Diaphragm pressure gauge are used for measuring mechanical pressure.
We saw in details about bourdon tube pressure gauge working principle, working, types of working pressure etc. Bourdon tubes are easy to use and direct pressure measurement device. Other elastic pressure gauges we saw bellow pressure gauge and diaphragm.
We also saw some other types of the pressure transducer. We saw the strain gauge pressure transducer working principle, construction, and applications.
If you have any question related to pressure transducer then comment. I surely help you with your doubt.