This document discusses temperature and flow measurement. It begins by defining temperature and the common units used to measure it. There are two main methods for measuring temperature - electrical and non-electrical. Electrical methods include thermocouples, thermistors, and RTDs, which convert temperature into an electrical signal. Non-electrical methods include infrared thermometers and glass thermometers. The document also defines flow and common flow measurement units. Main flow measurement devices are discussed, including orifice plates, vortex meters, pitot tubes, and magnetic and turbine flow meters. These devices are used across industries like oil/gas, water treatment, and manufacturing.
2. Temperature
Introduction to Temperature
Measuring units of Temperature
Temperature measuring methods, Working principals
and there uses.
3. Introduction to Temperature
Temperature is a physical quantity that expresses hot
and cold.
Temperature is the degree of hotness and coldness of
object with respect to standard value.
5. Temperature measuring Methods
There are two types of temperature measuring
methods.
1. Electrical Method
2. Non Electrical Method
6. Electrical Method
Measuring temperature in electrical methods, the
temperature signal is converted into electrical signal
either through a change in resistance or voltage. The
following elements are used to convert temperature
into electrical signal.
1. Thermocouple
2. Thermistor
3. Resistance Temperature Detector (RTD)
7. Thermocouples
Thermocouple is a sensor used to measure temperature.
Thermocouple consist of two wire legs made from different
metals (antimony and bismuth, copper and iron). The wire legs
are welded together at one end creating a junction.
Thermocouple are voltage device that indicate temperature
measurement with a change in voltage. As temperature goes up,
the output voltage of the thermocouple rises.
9. Thermistors
The word Thermistors is a combination of thermal
and resistor. Thermistors are made up of mixture of
metallic oxides, pressed into wafers and then cut to
chip size. A thermistor is a type of resistor whose
electrical resistance varies with changes in
temperature.
10. Thermistors
There are two types of Thermistors:
1. Negative Temperature Co-efficient (NTC):
Decrease resistance as the temperature increases.
2. Positive Temperature Co-efficient (PTC): PTC has
high positive temperature coefficient, which
increases in resistance as the temperature increases.
Applications:
Food industries, Scientific laboratories, Industrial
processes, Liquids and ambient gasses and
Biological applications etc.
11. Resistance Temperature Detector (RTD)
Resistance Temperature Detector (RTD), also called
Resistance Thermometers, An RTD is a type of
temperature sensor that changes electrical wire
resistance as changes in temperature. RTD is useful
only when it connected to an electric circuit. Mostly
it’s made up from Copper, Nickel and platinum.
12. Applications
RTD is used in automotive to measure engine temperature
Food Industry
Medical Research
Textile Production
Air Conditioning and Refrigeration
14. Infrared Thermometer
Infrared thermometers employ a lens to focus the
infrared emitting from the object onto a detector
known as a thermopile. When the infrared radiation
falls on the thermopile surface, thermopile sense
radiations and forward output signal.
16. Glass Thermometer
Liquid as expand as temperature
rises. Device consists of small
bore glass tube & thin wall glass
bulb. Filled with mercury.
Applications:
Glass Thermometer is used in
Chemical Labs, Industries and
also doctor use this type of
thermometer.
17. Flow
Introduction to Flow
Flow Measuring Units
Flow Measuring Devices and their working Principal
Applications of flow measuring instruments
18. Introduction to Flow
Flow of Fluids that passes a specific point in a
specified period of time. Flow rate refers as a velocity
of the fluid or how fast fluid moves. A flow meter (or
flow sensor) is an instrument used to measure linear,
nonlinear, volumetric flow rate of a liquid or a gas.
Flow measuring Units:
1. Cubic feet per second (ft3/s)
2. Cubic meters per second (m3/s)
3. Gallons per minute (GPM)
19. Flow Measuring Devices
The common types of flowmeters with industrial
applications are listed below
1. Orifice Plate
2. Vortex Meter
3. Pitot Tube
4. Flow Nozzle
5. Magnetic Flow Meter
6. Turbine Flow Meter
20. Orifice Plate
The liquid or gas whose flow rate is to be determined is
passed through the orifice plate. This creates a pressure
drop across the orifice plate which varies with the flow
rate, resulting in a differential pressure between the outlet
and inlet pressure. This pressure drop is measured and is
used to calculate the flow rate of the fluid or gas.
22. Vortex Meters
The vortex meter is a flow meter which can be used
for metering, measurement and control of most steam,
gas and liquid flow for a very unique medium
versatility.
Applications:
Water and gas, but one of
the most common is for
steam flow measurement.
23. Pitot Tube
The pitot tube installed in the flow stream
measures the direct pressure at the contact pitot
tube hole and a second measurement is required,
being of static pressure. The difference between
the two measurements gives a value for dynamic
pressure.
24. Applications
It is widely used to determine the airspeed of
an aircraft
Water speed of a boat
Air and gas flow velocities in certain industrial
applications.
25. Flow Nozzle
When a flow nozzle is placed in a pipe carrying whose
rate of flow is to be measured, the flow nozzle causes
a pressure drop which varies with the flow rate. This
pressure drop is measured using a differential pressure
sensor and when calibrated this pressure becomes a
measure of flow rate.
26. Magnetic Flow Meter
The measuring principle is based on “Faraday’s Law of
induction. “When a conductor moves in the magnetic field,
it induces voltages that are perpendicular to the magnetic
field and direction of flow. The magnetic flow meter is a
volumetric flow metering device. The magnetic flow meter
is designed to measure the value of the voltage induced
when a conductive fluid passes through the body of the
meter (magnetic field).
28. Turbine Flow Meters
Turbine flow meters use the mechanical energy of the
liquid to rotate a rotor within the flow stream. The
rotational speed is directly proportional to the velocity
of the fluid traveling through the meter. These meters
are used in multiple industries to reliably measure
liquids, gases and vapors.