Hagen Poiseuille equation gives the relationship between pressure drop and flow rate of a fluid through a long cylindrical pipe. Measurement of amount of fluid flows within a time interval is quite important in a process industry for the smooth and safe running of different operations. Since the fluid is considered as incompressible,įrom Continuity Equation, v 1A 1 = v 2A 2įrom Eq(3) we can calculate flow rate(Q=Area x average velocity) through the duct using pressure difference p 1 – p 2 Now considering any two points in the liquid, G = acceleration due to gravity considered as 9.81 m.s -2 As the name suggest it looks like the alphabet U, the bottom portion of the glass tube is filled with heavy liquid like mercury, water and air are also used as per requirement.įlow of fluid through a venturimeter Image Credit: wikipediaīernoulli’s Principle can be expressed in terms of a mathematical formula as below: U tube manometer is a device used to measure the pressure difference between two points which may be in the same pipe or in two different pipes. Differential Pressure Gauges and Differential U-tube Manometer are used to calculate the pressure difference between two points of same liquid or different liquids.ĭifferential pressure gauges consists of two inlet ports, each port is connected to one of the pipes or sources whose pressure is to be monitored. H is the height of the fluid column in ‘m’Ī swimmer experiences more pressure as he goes deeper underwater because of the more and more weight on the top as well as the air above him. G is the acceleration due to gravity considered as 9.81 ms -2 P is the pressure exerted by the liquid in Nm -2 The formula used to calculate hydrostatic pressure is shown below: Hydrostatic Pressure at different depths Image Credit: wikipedia The pressure of a liquid at rest at a certain depth due to gravitational force is known as Hydrostatic Pressure and hydrostatic pressure increases as the depth measured from the surface increases because of the increasing weight of the fluid exerts more downward force on the lower liquid layers. Hydrostatic Pressure Difference is specific measurement of liquid pressure above a vertical datum at different points or at different heights from the datum line.
To determine the respiratory flow in medical devices, air flow blockages in different devices, clogged filter detection in extractor fans, air conditioner, exhaust ducts are the examples of applications where Pressure difference monitoring plays an important role. If a part of a pipeline gets clogged, there is a change in pressure which makes a change in Pressure Difference, an operator can easily detect the exact blockage point and clean the pipeline to ensure the smooth flow of the fluid.įor a maximum value of pressure difference, we may have to change the filter otherwise it may lead to damage or corrosion. Pressure Difference is continuously monitored in industries to know whether there is any clog or contaminates through a pipeline. Pressure device for industry system Image Credit: unsplash