SCHOOL OF MECHANICAL AND MANUFACTURING ENGINEERING
ME155P / E02
INDUSTRIAL AUTOMATION AND CONTROL
WRITTEN REPORT ON
TEMPERATURE MEASURING INSTRUMENTS
EXPERIMENT NO. 1
NG SY, JAN LAWRENCE F.
ENGR. PAULO RAFAEL V. MERIS
NOVEMBER 26, 2018
In this experiment, students are to perform the task of measuring the temperature of the hot water to be boiled using a boiler and ice by using the infrared thermometer, thermistor and thermometer. The main objective of the experiment is to check the accuracy of the infrared thermometer, thermistor and the thermometer. It took a lot of time to boil the water since the aim of the students is to boil the water using the boiler to 100 degrees or nearly a hundred degrees. Students are required to perform 5 trials per temperature measuring tool. Also, the ambient room temperature is required to be measured twice. Then the average would be computed.
1. Evaluate the accuracy and reproducibility of the Laboratory Thermometer and Infrared thermometer
2. Discuss the instrument parameters that are applicable to the listed instruments
3. Identify and discuss the industrial applications of the listed instruments
TABLE OF CONTENTS
TITLE PAGE i
TABLE OF CONTENTS iii
THEORIES AND PRINCIPLES 1
FINAL DATA SHEET / SET-UP 9
THEORIES AND PRINCIPLES
The tendency of a matter to change its area, shape and volume in response to a temperature change. If a material or substance is heated up, its particles would move faster that would create greater distance with other co-particles. There is degree of expansion coefficient in linear expansion, volume expansion and area expansion.
Linear expansion coefficient is a factor in change in linear length of a particular material when exposed to heat, the higher the linear expansion coefficient of an object then the material would heat up slower unlike if the linear expansion coefficient of an object is lower, the material heats up easier. The formula for linear expansion is ?L=?L?T, where the change in length is equivalent to the linear expansion coefficient multiplied to the original length and the change temperature.
Like the aluminum kettle used for boiling water, it does not take a long time for a aluminum kettle to heat up since the fractional expansion per degree Celsius is just 24×10^-6.
The formula for linear expansion is ?L=?L?T, where the change in length is equivalent to the linear expansion coefficient multiplied to the original length and the change temperature.
Area expansion, on the other hand, is the change in area of a particular material, relating it to the linear expansion, linear expansion is multiplied to two in using the formula, and then the change in length is changed to change in area while the original length is changed to original area dimension.
Volume Expansion, on the other hand, is the change of a particular material in all directions, if related to linear expansion; linear expansion is multiplied into 3. The change in volume is divided into the original volume, equal to the coefficient of volume expansion multiplied to the change in temperature.
Thermocouple is an electronic device that has 2 dissimilar electrical conductors forming electrical junctions at different temperatures. It is a versatile temperature sensor that is used from regular usage to industrial usage. It is essential to fully understand a thermocouple temperature sensor before using it and to what type of material of electrical conductors for the suitable application.
3. Infrared thermometer
The infrared thermometer has a lens used to focus the IR infrared energy on to a detector of temperature that converts the energy into electrical signal that can determine the temperature without direct contact into the surface of an object or substance to be measured after compensated for the ambient temperature variation. It is sometimes used since it is very convenient to use and due to other measuring devices do not provide accurate measurement in temperature.
Boiler is a commonly used tool to heat up a certain type of fluid while in a boiler, it is important to inspect the size of a boiler, the type of boiler, material of the boiled and the amount of liquid to be boiled to save time and electricity or oil. If the concept is applied in factories and industry, the costing and energy consumption is greatly considered to save money, the efficiency of boiling a type of fluid in factory should be applicable to the type of boiler to be used. There are two ways of measuring the efficiency of boiling; these are the direct and indirect methods. The direct method is more usable and common where the formula used is
Boiler efficiency = power out / power in = (Q * (Hg – Hf)) / (q * GCV) * 100%
Where Q is the rate of flow in kg/h, Hg is the enthalpy of saturated steam in kcal/kg, Hf is the enthalpy of feed water in kcal/kg, q is the rate of fuel use in kg/h, GCV is the gross calorific value in kcal/kg. On the other hand, the indirect method is more complicated, where the following factors are concerned, like the ultimate analysis of fuel, percentage of oxygen or carbon dioxide at flue gas, flue gas temperature at outlet, ambient temperature in deg c and humidity of air in kg/kg, GCV of fuel in kcal/kg, ash percentage in combustible fuel, GCV of ash in kcal/kg.
• If the boiler is oversized, the fuel bills will be excessive.
• If the boiler is undersized, it may not generate enough heat in winter.
The ideal size for a boiler is one that just copes adequately on the coldest day of the year. Most boilers are oversized by at least 30%. This is due to the way systems used to be calculated with a card calculator. These were always over-calculated “to be on the safe side.” Today, the emphasis is on energy conservation, and the fact that heat loss calculations can be done very accurately, means there is no need to oversize. This allows smaller radiators and less water in the system, which in turn, means a smaller boiler and reduced costs for both installation and fuel bills.
The boiler does not directly govern the amount of radiators fitted to the system. It is the power of
the pump and circulation of the water through adequately sized pipes that determines the number
of radiators you can have. But the total output of all the radiators, pipes, and cylinders determines the size of the boiler.
The boiler is not the heating system; it is only one of the parts in the global heating system. As shown in ”’Figure 1”’, a heating system consists of four main parts:
1. Boiler/burner combination (the part producing the heat)
2. Piping with pumps and valves (the part distributing the heat)
3. Radiators and convectors (the part emitting the heat to the room)
4. Control equipment such as room thermostat and outside temperature control (the part controlling room and water temperature)
Figure 1. Different parts of heating system
There are two general types of boilers: ”fire-tube” and ”water-tube”. Boilers are classified as “high-pressure” or “low-pressure” and “steam boiler” or “hot water boiler.” Boilers that operate higher than 15 psig are called “high-pressure” boilers.
A hot water boiler, strictly speaking, is not a boiler. It is a fuel-fired hot water heater. Because of its similarities in many ways to a steam boiler, the term ”hot water boiler” is used.
• Hotwater boilers that have temperatures above 250° Fahrenheit or pressures higher than 160 psig are called ”high temperature hot water boilers”.
• Hotwater boilers that have temperatures not exceeding 250° Fahrenheit or pressures not exceeding 160 psig are called ”low temperature hot water boiler”s.
Heating boilers are also classified as to the method of manufacture, i.e., by casting (cast iron boilers) or fabrication (steel boilers). Those that are cast usually use iron, bronze, or brass in their construction. Those that are fabricated use steel, copper, or brass, with steel being the most common material.
”’Steel boilers”’ are generally divided into two types: ”fire-tube” and ”water-tube”.
Fire-tube boilers are:
• Relatively inexpensive
• Easy to clean
• Compact in size 4
• Available in sizes from 600,000 btu/hr to 50,000,000 btu/hr
• Easy to replace tubes
• Well suited for space heating and industrial process applications
Disadvantages of fire-tube boilers include:
• Not suitable for high pressure applications 250 psig and above
• Limitation for high capacity steam generation
Figure 2. Fire-tube Boiler Gas Flow
In a water-tube boiler (”’Figure 3”’), the water is inside the tubes and combustion gases pass around the outside of the tubes. The advantages of a water-tube boiler are a lower unit weight-per-pound of steam generated, less time required to raise steam pressure, a greater flexibility for responding to load changes, and a greater ability to operate at high rates of steam generation.
• Are available in sizes far greater than a fire-tube design , up to several million pounds-per-hour of steam
• Are able to handle higher pressures up to 5,000 psig
• Recover faster than their fire-tube cousin
• Have the ability to reach very high temperatures
Disadvantages of the water-tube design include:
• High initial capital cost
• Cleaning is more difficult due to the design
• No commonality between tubes
• Physical size may be an issue
Figure 3: Water-tube Boiler
Cast Iron Boilers
Cast iron boilers are made in three general types: horizontal-sectional, vertical-sectional, and one-piece. Most of the sectional boilers are assembled with push nipples or grommet type seals, but some are assembled with external headers and screw nipples. Horizontal-sectional, cast iron boilers are made up of sections stacked one above the other, like pancakes, and assembled with push nipples. Vertical-sectional, cast iron boilers are made up of sections standing vertically, like slices in a loaf of bread. One-piece cast iron boilers are those in which the pressure vessel is made as a single casting.
Steam and Condensate Boiler System
Boilers are generally used to provide a source of steam or hot water for facility heating and process needs.
In steam and condensate systems, heat is added to water in a boiler causing the water to boil and form steam. The steam is piped to points requiring heat, and as the heat is transferred from the steam to the building area or process requiring heat, the steam condenses to form condensate. In some very low-pressure saturated steam heating applications, the steam distribution piping may be sized to slope back to the boiler so that the steam distribution piping also acts as the condensate return piping (single-pipe system).
Figure 4: Steam and Condensate Boiler System
A turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating electrical power when combined with a generator. A turbine is a turbo machine with at least one moving part called a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades so that they move and impart rotational energy to the rotor. Early turbine examples are windmills and waterwheels.
Figure 5. a steam turbine
INTERNAL COMBUSTION ENGINE
Internal combustion engines (ICE) are the most common form of heat engines, as they are used in vehicles, boats, ships, airplanes, and trains. They are named as such because the fuel is ignited in order to do work inside the engine. The same fuel and air mixture is then emitted as exhaust. This can be done using a piston (called a reciprocating engine), or with a turbine.
Figure 6. Four stroke engine
Figure 7. Two stroke engine
Figure 8. Rotary engine
FINAL DATA SHEET / SET-UP
Figure 9. Boiled water measured using a thermistor
Figure 10. Boiled water measured using thermometer and Infrared Thermometer
Figure 11. Ice-water temperature measured using thermometer and Infrared Thermometer
Figure 12. Ice-water temperature measured using thermistor
Considering time efficiency, it is considered that the infrared thermometer is the most time-efficient than laboratory thermometer and the thermistor since it does not need to be calibrated again. The thermometer is more accurate due to they are closer to the standard values as compared to the infrared thermometer and also they are in contact to the substance being examined. The thermometer is the most accurate while the infrared thermometer being the least accurate of these due to it being a non-contact thermometer is one of its disadvantages in this kind of experiments.
In this experiment we used thermometer and infrared thermometer and thermistor to get the temperature of ice and the boiled water. Since not all the group can perform at the same time on the boiler, my recommendations in this experiment is additional equipment or take faster turns in performing the experiment on boiler. So that the other group will not have to wait for their next turn before they can start the experiment. I also recommend to those who are taking this experiment to have patience while using the laboratory thermometer because they need to be cooled down to the ambient temperature per trial for more accurate results. Lastly, I would recommend testing other types of temperature sensing instruments so that the other engineering students can see and interpret its working principle.
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