Showing posts with the label Pressure measuring devices

What is the use of pressure switch?

What is the use of pressure switch?  A pressure switch is used to detect low pressure condition or high pressure condition.

Well type Manometer

  Well type Manometer   The well type monometer is widely used because of having only one leg.  The main difference between a U-tube manometer and a well type manometer is that the U-tube is substituted by a large well such that the variation in the level in the well will be negligible and instead of measuring a differential height, a single height in the remaining column is measured. It consist of a large diameter vessel with one side connected to very small size tube, so that the zero level moves very little when the pressure is applied. The area of well is much greater than the area of tube. In general this ratio is greater than 10. Accuracy is achieved by setting zero level of well at zero level of scale before each reading of table. The sensitivity of such monometer is good. Well Manometer Principle Well Manometer same as the U-tube except for the reservoir on the high-pressure side. It is sometimes called a single column gauge. The manometer consists of a metal well of large cro

U-Tube Manometer

  monomers Manometer is a device used to measure pressure at a single or multiple points in a single or multiple pipelines, by balancing the fluid column by the same or another column of fluid. Manometers work by the principle that a column of fluid in a tube will rise or fall until its weight is in equilibrium with the pressure differential between the two ends of the tube. For a pressure difference P is the height difference h between the level of liquid in the two halves of the tube A and B, is given by the equation P = pgh, where p is the density of the fluid in the tube. U-Tube Manometer “A U-tube manometer, in which differential pressure is measured as the difference 'h' between the high-pressure reading and the low-pressure reading, multiplied by the density of the liquid in the tube.” The difference in height of the liquid represents the applied pressure. In U-tube manometer we measure the pressure as: P= sp wt * height( fluid)- sp wt * height( Hg) Introduction

Bourdon tube Working principle and Applications

  Bourdon Tubes Bourdon Tubes are known for its very high range of differential pressure measurement in the range of almost 100,000 psi (700 MPa). It is an elastic type pressure transducer. The device was invented by Eugene Bourdon in the year 1849. The basic idea behind the device is that, cross-sectional tubing when deformed in any way will tend to regain its circular form under the action of pressure. The bourdon pressure gauges used today have a slight elliptical cross-section and the tube is generally bent into a C-shape or arc length of about 27 degrees. The detailed diagram of the bourdon tube is shown below. As seen in the figure, the pressure input is given to a socket which is soldered to the tube at the base. The other end or free end of the device is sealed by a tip. This tip is connected to a segmental lever through an adjustable length link. The lever length may also be adjustable. The segmental lever is suitably pivoted and the spindle holds the pointer as shown in the f

Pressure Measurement

  Pressure Measurement   This module will examine the theory and operation of pressure detectors (bourdon tubes, diaphragms, bellows, forced balance and variable capacitance). It also covers the variables of an operating environment (pressure, temperature) and the possible modes of failure. General Theory   Pressure is probably one of the most commonly measured variables in the power plant. It includes the measurement of steam pressure; feed water pressure, condenser pressure, lubricating oil pressure and many more. Pressure is actually the measurement of force acting on area of surface.  We could represent this as:  Pressure = Force/Area or P=F/A The units of measurement are either in pounds per square inch (PSI) in British units or Pascals (Pa) in metric. As one PSI is approximately 7000 Pa, we often use kPa and MPa as units of pressure. Pressure Scales   Before we go into how pressure is sensed and measured, we have to establish a set of ground rules. Pressure varies depending on al

Pressure Measuring Devices

Pressure Measuring Devices Pressure  Pressure is the force acting per unit area and it is expressed mathematically as pressure equal to the force divided by the area and the unit of pressure is newton per meter squared and newton per meter squared is also called pascal. And common types of pressure are atmospheric pressure, absolute pressure, vacuum pressure, gauge pressure. Common units of pressure are pascal, kilogram per square centimeter, bar, pound per square inch or psi, mmh2o, mmhg, inh2o, inhg. P = Force(F)/ Area(A) , pascal (N/m²) Pressure measuring devices Pressure measuring instruments are barometer, manometer, pressure tube, diaphragm pressure gauge 1. Barometer A barometer is a device that measures atmospheric pressure and common types of barometers are digital barometers, water barometers and mercury barometers. 1. Digital Barometer Digital barometer is the most common barometer for measuring pressure and Digital barometer is used for micro chip or IC to measure air press