Whenever a very High Fluid Pressure is to be measured a Mechanical Gauge is best suited for the purpose. Mechanical Gauges is also used for the measurement of pressure is boilers or other pipes, where tube gauges cannot be conventionally used.

There are many Types Of Gauges available in the market. But the principle on which all these Gauges Work is almost the same. following three type of gauges are important from the subject point of view:-

What are the types of mechanical gauges?

1.  Bourdon's Tube Pressure Gauge
2.  Diaphragm Pressure Gauge
3.  Dead Weight Pressure Gauge

The pressure above or below the atmospheric pressure may be easily measured with the help of a bourdon's tube pressure gauge. A burdons tube pressure gauge in it is simplest form consists of an elliptical tube ABC. Bent into an Arc of a circle as shown in figure. This bent of tube is called burdon's tube.

When the gauge tube is connected to the fluid (whose pressure is required to be found out) at C the fluid under pressure flow into the tube. the Bourdon's Tube as a result of the increased pressure tend to strengthen itself.

Since the tube is encashed in a circular karva therefore it tend to become circular instead of straight. With the help of a simple pinion and sector attachment the elastic deformation of the bourdon's tube rotated the pointer. This pointer move over a calibrated scale which directly give the pressure as soon in figure.

Mechanical gauge diagram

The pressure above or below the atmospheric pressure is also found out with the help of Diaphragm Pressure Gauge. Order from pressure gauge in its simplest form consists of the diaphragm ( instead of bourdon tube is article first of bourdon tube pressure gauge of this blog).

When the gauge is connected to the fluid (whose pressure is required to be found out) at C, the fruit under pressure causes from the formation of the Diaphragm. With the help of some pinion arrangement the elastic deformation of the diaphragm rotates the pointers. This pointer moves over a calibrated scale which directly give the pressure as shown in figure.

A diaphragm pressure gauge in generally used to measure relatively low pressure.

It is the most accurate and pressure gauge which is generally used for the calibration of the other pressure gauge in a laboratory. Did weight pressure gauge in its simplest form consists of piston and cylinder of known area which is connected to a fluid through a tube as shown in figure.

The pressure of fluid in the pipe is calculated for from the relation,

A pressure gauge to big calibrated is treated on the other end of the tube as shown in figure by changing the weight on the piston the pressure on the fluid is calculated and marked on the gas at the respective point indicated by the pointer.

 A small error due to frictional resistance to the motion of the piston come into play. but the same may be avoided by taking adequate precautions.




#Mechanical_gauge_diagram  #Classification_of_gauges

A fluid consists of an innumerable number of particles and relative positions are never fixed. Whenever upload is in motion these particles move along certain lines, depending upon the characteristic of the fluid and the shape of the passage through to reach the fluid particles move.

For complete analysis of the fluid motion it is necessary to observe the motion of the fluid particles at various point and times. For The mathematical analysis of the blood motion following two method are generally used:-

It deals with the study of flow pattern of the individual particle. In this method the parts pressed by a particle under consideration with the passage of time is studied in detail.

 It deals with the study of flow pattern of all the particles simultaneously at one section, in this method the path traced by all particle at one section one time are studied in detail.

1. The generally example to explain both the method is the study of movement of a number of vehicles on a busy road. The Lagrangian method deals with the the the study of of the movement of only one vehicle through a specified distance. The Eulerian method deals with the study of movement of all the vehicles on the road at one section and at one instant.

2. In the study of hydraulics fluid mechanics and astrophysics the variance method is commonly used because of its mathematical simplicity. Moreover in fluid mechanics the movement of an individual fluids particles is not of much importance.

I think you have known motion of fluid particles clearly if you have any doubt about this you may comment below the comment box is open for you.

It has been established , since long, that the year process some weight. Subsequently, it was also thought that the air, due to its weight must exert some pressure on the surface of the Earth.

Since the air compressible therefore its density is different at different heights. the density of air has also been found to verify from time to time due to the changes in its temperature and humidity.

It is to thus obvious that due to these difficulties the atmospheric pressure cannot be calculated as is done in the case of of liquids. How ever it is measured by the height of the column of liquid that it can support.

It has been observed that at sea level the pressure exerted by the column air of 1 square metre cross sectional area and of height equal to that of the atmosphere is 103 kN. Thus we may say that the atmospheric pressure at the sea level is 103 kN per m² (103kPa). It can also be expressed as 10.3 metres of water.

 In terms of equivalent water column are 760 mm of mercury in terms of equivalent Mercury column.