Used since 1849, pressure gauges have had many applications, from depth to altitude measuring and more. Classified in different types, they show the increase and reduction of pressure in different fields. Here is the list of some of the pressure gauges used today.
Air pressure gauges: Measuring the optimal amount of air needed to fill the object, this gauge can usually be used for objects that contain air, such as tires. Too little air makes the tire flatten quicker, but too much can make it wear unevenly and even cause it to explode. An air pressure gauge will show the number of pounds per square inch (PSI) of air in the object.
Differential pressure gauges: This gauge, a u-shaped glass tube partially filled with fluid (such as mercury), shows the variations in pressure between two points. It simplifies the operators' job, because they don't have to monitor pressure at two points and calculate the difference. An example is a liquid-column manometer used to measure vacuum pressures.
Oil pressure gauges: These gauges show whether the level of oil is safe. Machine engines use oil to lubricate their parts while they're in motion. It is crucial that natural friction between the parts is eliminated, so these gauges help keep the level oil at the safe level.
Digital pressure gauges: This type of gauge is diverse in its applications, including pharmaceutical, food, or automotive. The applied pressure is seen on the numerical displays. These gauges are also often used to monitor hazardous materials.
Diaphragm pressure gauges: These aneroid gauges have a capsule that's separated by a flexible diaphragm -- hence the name. One end of this capsule is opened to the external pressure being measured. The other end is connected to the known pressure. The diaphragm's deflection from a leveled position exhibits the pressure difference. These gauges can be found in the chemical or petrochemical industries, plastics and paper manufacturers, machine and plant settings, etc.
Bourdon pressure gauges: This early type of pressure gauge is still widely used for measuring pressure in different liquids and gasses. It consists of circular curved tubes with an oval cross section that straighten out when the pressure increases. These gauges are used in simple devices (such as barometers) and more specialized ones in medical, industrial, or mechanical settings. However, they can measure pressure only up to 60 bar, after which they can be easily damaged.
Nick Murden is a keen amateur engineering enthusiast from South East England who writes regularly about what is happening in the engineering world. He works for TC Fluid Control.