A

PROJECT REPORT

ON

STUDY OF DIFFERENT TYPES OF FIELD INSTRUMENTS

Prepared by:

1) Miteshkumar Chandubhai Domadiya (ID no. 093008)2) Amit Vinubhai Kachhadiya (ID no. 093015)3) Bhaveshkumar Parabatbhai Kachhot (ID no. 093016)4) Dhara Yogeshbhai Patel (ID no. 093030)5) Hardik Pravinbhai Lad (ID no. 093017)

Guided by:

Prof. Ashish G. Patel, Mr. Bhagvan J. Koshti,

Instrumentation & Control Department, Manager (Instrumentation),

Faculty of Technology, Color Division,

Dharmsinh Desai University, Site-West,

Nadiad – 387 001. Atul Ltd.,

Atul- 396 020

Dharmsinh Desai UniversityNadiad – 387 001

This is to certify that the work reported in this Project

Report titled To Study of Different Types of Field

Instruments is the bonafide work of Mr. / Miss

Miteshkumar Chandubhai Domadiya, Roll No. IC-11,

Identity No. 093008 of Bachelor of Technology Semester-

VI in the branch of Instrumentation & Control

Engineering, during the academic year 2011-2012.

Certificat

e

Prof. Ashish G. Patel Prof. Saurin R. Shah

Project Guide Head of the Department

Dharmsinh Desai UniversityNadiad – 387 001

This is to certify that the work reported in this Project

Report titled To Study of Different Types of Field

Instruments is the bonafide work of Mr. / Miss

Bhaveshkumar Parabatbhai Kachhot, Roll No. IC-17,

Identity No. 093016 of Bachelor of Technology Semester-

VI in the branch of Instrumentation & Control

Engineering, during the academic year 2011-2012.

Certificat

e

Prof. Ashish G. Patel Prof. Saurin R. Shah

Project Guide Head of the Department

Dharmsinh Desai UniversityNadiad – 387 001

This is to certify that the work reported in this Project

Report titled To Study of Different Types of Field

Instruments is the bonafide work of Mr. / Miss Dhara

Yogeshbhai Patel, Roll No. IC-11, Identity No. 093008

of Bachelor of Technology Semester-VI in the branch of

Instrumentation & Control Engineering, during the

academic year 2011-2012.

Certificat

e

Prof. Ashish G. Patel Prof. Saurin R. Shah

Project Guide Head of the Department

Dharmsinh Desai UniversityNadiad – 387 001

This is to certify that the work reported in this Project

Report titled To Study of Different Types of Field

Instruments is the bonafide work of Mr. / Miss Hardik

Pravinbhai Lad, Roll No. IC-18, Identity No. 093017 of

Bachelor of Technology Semester-VI in the branch of

Instrumentation & Control Engineering, during the

academic year 2011-2012.

Certificat

e

Prof. Ashish G. Patel Prof. Saurin R. Shah

Project Guide Head of the Department

Dharmsinh Desai UniversityNadiad – 387 001

This is to certify that the work reported in this Project

Report titled To Study of Different Types of Field

Instruments is the bonafide work of Mr. / Miss Amit

Vinubhai Kachhadiya,, Roll No. IC-16, Identity No.

093015 of Bachelor of Technology Semester-VI in the

branch of Instrumentation & Control Engineering, during

the academic year 2011-2012.

Certificat

e

Prof. Ashish G. Patel Prof. Saurin R. Shah

Project Guide Head of the Department

ACKNOWLEDGEMENT

We would take an immense pleasure in thanking our guide Mr. Bhagvan J. Koshti (Manager of

– Instrumentation Division), and our mentor Mr. Bharat Patel well as other engineers and staff

for imparting us technical and practical knowledge. They helped us in understanding various

technical aspects, by practical applications with a lot of patience, consideration and concern.

In addition to, we have a respect for all the technicians of the organization who helped us a lot

in nurturing our technical aspects.

CONTENTS

CHAPTER NO CHAPTER TITLE

1 INTRODUCTION

2 TEMPERATURE MEASUREMENT

3 LEVEL MEASUREMENT

4 FLOW MEASUREMENT

5 PRESSURE MEASUREMENT

6 OTHER FIELD INSTRUMENTS

7 CONTROL VALVES

CHAPTER-1

INTRODUCTION

Company Profile:

Atul Limited is a member of the Lalbhai Group, one of the oldest business houses in India. Today, Atul is one of India's largest integrated chemical companies, with a turnover of Rs 1500 crore. The Company is rated among the top five global producers in several niche chemicals; it serves a number of industries in India, as well as around the world, in the fields of aerospace, automobiles, agriculture, construction, fragrance and flavors, and paper and textiles.

History:

ATUL, nestled within the green and tranquil environs, is one of the largest chemical complexes of its kind in Asia, a dream of a farsighted and enlightened industrialists, the late Shri Kasturbhai Lalbhai.

The story of ATUL began in 1945, when Shri Kasturbhai Lalbhai met Mr. Sidney C Moodey, the n the President of American Cyanamid, and the idea of setting up a Dyestuff unit in India was conceived. This was the time when the independence moment in India has reached a crescendo, and the desire to be self- reliant was widely prevalent. Shri Kasturbhai Lalbhai saw, in this proposal, self-reliance for India in Dyes on the one hand, and backward integration of his businesses of textiles on the other. It was Shri B K Muzumdar, a scholar and economist, who translated Shri Kasturbhai Lalbhai’s vision in to reality.

In 1947, ATUL, meaning ‘Incomparable’, was set up on bank of the river Par, in Valsad District in Gujarat, 200km north of Mumbai. The first manufacturing plant was inaugurated by India’s first Prime Minister Pandit Jawaharlal Nehru. From a modest beginning with few dyes, ATUL ltd has today emerged as a chemical giant, manufacturing an extensive range of dyes, Agrochemicals, Basic chemicals, Bulk drugs, Speciality chemical, Polymers, Pharmaceuticals and Intermediates thereof.

Over the years ATUL joined hands with American Cyanamid Imperical Chemical Industries (ICI), saw spun off to Zeneca and Ciba-Geigy to promote Cyanamid India, Atic Industries and Cibatul ltd respectively. In 1995, Zeneca diversted its shareholding in Atic to ATUL thereby Broadening the product range of Dyes in ATUL. In 1999, Cibatul also merged with ATUL. A giant chemical complex, spread over 1200 acres of afforested land, was once a barren and backward area. The complex provides direct employment to about 2700 people.

Atul is one of India's largest integrated chemical companies and among the top five global producers of several niche chemicals. The Company caters to the aerospace, automobiles, agriculture, construction, fragrance and flavors, and paper and textiles industries. Atul produces over 700 diverse products through its seven business divisions:

1)Aromatics

2)Colors

3)Crop Protection

4)Floras

5)Pharma & Inters

6)Polymers

We at the Atul Limited are placed in Colors (CO) Division for undergoing our UG level Project.

Colors (CO) Division:

Colors division is the largest business division of ATUL ltd, manufacturing a wide range of dyestuffs for the textiles, leather, paper, wool and silk industries. The CO division is one of the leading supplier of dyestuffs in India and export nearly 55% of its production to more than 75 countries worldwide. It has a wide range of over 350 dyes.

The division manufacturing operation started with sulphur dyes in 1952. In quick succession, other classes of dyes were added to the product range making ATUL as a pioneer in its field of business.

Atic Industries ltd, a 50:50 joint venture between ATUL ltd and Zeneca plc was established in 1955. Off late 1995, when Zeneca decided to diversted its textile colors business worldwide, ATUL bought over Zeneca’s stake in Atic Industries. Subsequently in the same year, Atic industries was amalgamated in to ATUL and the integrated dyestuff business was formed under the umbrella of CO division.

The range of dyes offered are:

*Acid dyes *Dye intermediates

*Azoic coupling components *Fluorescent brightening agents

*Azoic developing components *Reactive dyes

*Disperse dyes *Sulphur dyes

*Direct dyes *Vat dyes

The Colors Division has received a highest export award for a large scale unit (2002-03) by Dyestuff Manufacturer’s Association of India.

We also have received ISO 9001 Certificate. We are a member of ETAD.

Besides India, major market for colors are Germany, USA, Bangladesh, UK, Switzerland, China, Turkey, Mauritania, Brazil, Hong Kong, Egypt, Italy, Spain and Australia.

CHAPTER-2 TEMPERATURE MEASUREMENT

What is temperature?

Temperature is a measure of the average heat or thermal energy of the particles in a substance. Temperature does not depend on the size or type of object.

The sensors used for measuring temperature are listed below

Different types of thermometers Thermocouples Resistance thermometer Pyrometers etc.

They are used according to their range.

Temperature measures in different four scales named Fahrenheit, Centigrade, Kelvin, Rankine and Reaumur.

In industries most commonly temperature measures in Fahrenheit and Centigrade.

1) RESISTANCE TEMPERATURE DETECTOR:

Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature by correlating the resistance of the RTD element with temperature. Most RTD elements consist of a length of fine coiled wire wrapped around a ceramic or glass core. The element is usually quite fragile, so it is often placed inside a sheathed probe to protect it. The RTD element is made from a pure material whose resistance at various temperatures has been documented. The material has a predictable change in resistance as the temperature changes; it is this predictable change that is used to determine temperature.

A RTD Sensing element consists of a wire coil or deposited film of pure metal. The element’s resistance increases with temperature in a known and repeatable manner. RTD’s exhibit excellent accuracy over a wide temperature range.

Temperature range: -200 to 700ºC Sensitivity: the voltage drop across an RTD provides a much larger output than a

thermocouple. Linearity: Platinum and copper RTD’s produce a more linear response than thermocouples or

thermistors. RTD non-linearities can be corrected through proper design of resistive bridge networks.

The most commonly used element material is platinum with a resistance of 100 ohms @ 0ºC and a temperature coefficient (Alpha) of 0.00385 ohms/ohm/ºC.

Other element materials also used are copper, nickel and nickel-iron. Platinum elements predominate because of their wider range, and because platinum is the most repeatable and stable of all metals.

Tolerance of PT100 Ω (Alpha = 0.003850 @ 0ºC)

Connection / Wiring details:

Different connection Types. Standard Color code; A is white, B is red.

2 wireBasic connection where the lead is short. No lead wire compensation, introducing an error into the reading.

3 wire

Most common connection 3 wire, the instrument measures the lead wire resistance in the B legs and allows for this in its reading.

4 wire4 wire connection is the most accurate measurement. The instrument measures the lead resistance of all four lead wires removing these values for its reading

Duplex RTD

Duplex 3 wire RTD connection as per single RTD but two individual element windings.

Classes Of RTD :

TOLERANCE CLASS A BTOLERANCE 0.06% 0.12%RANGE -200°C to 650°C -200°C to 850°C

RTD Element Types:

There are three main categories of RTD sensors.

Thin Film Wire-Wound Coiled Elements

Thin Film Elements have a sensing element that is formed by depositing a very thin layer of resistive material, normal platinum, on a ceramic substrate. This layer is usually just 10 to 100 angstroms (1 to 10 nanometers) thick. This film is then coated with an epoxy or glass that helps protect the deposited film and also acts as a strain relief for the external lead-wires. Disadvantages of this type are that they are not as stable as their wire wound or coiled counterparts. They also can only be used over a limited temperature range due to the different expansion rates of the substrate and resistive deposited giving a "strain gauge" effect that can be seen in the resistive temperature coefficient. These elements work with temperatures to 300 °C.

Wire-wound Elements can have greater accuracy, especially for wide temperature ranges. The coil diameter provides a compromise between mechanical stability and allowing expansion of the wire to minimize strain and consequential drift. The sensing

wire is wrapped around an insulating mandrel or core. The winding core can be round or flat, but must be an electrical insulator. The coefficient of thermal expansion of the winding core material is matched to the sensing wire to minimize any mechanical strain. This strain on the element wire will result in a thermal measurement error. The sensing wire is connected to a larger wire, usually referred to as the element lead or wire. This wire is selected to be compatible with the sensing wire so that the combination does not generate an emf that would distort the thermal measurement. These elements work with temperatures to 660 °C.

Coiled elements have largely replaced wire-wound elements in industry. This design has a wire coil which can expand freely over temperature, held in place by some mechanical support which lets the coil keep its shape. This “strain free” design allows the sensing wire to expand and contract free of influence from other materials; in this respect it is similar to the SPRT, the primary standard upon which ITS-90 is based, while providing the durability necessary for industrial use. The basis of the sensing element is a small coil of platinum sensing wire. This coil resembles a filament in an incandescent light bulb. The housing or mandrel is a hard fired ceramic oxide tube with equally spaced bores that run transverse to the axes. The coil is inserted in the bores of the mandrel and then packed with a very finely ground ceramic powder. This permits the sensing wire to move while still remaining in good thermal contact with the process. These Elements works with temperatures to 850 °C.

The current international standard which specifies tolerance, and the temperature-to-electrical resistance relationship for platinum resistance thermometers is IEC 60751:2008, ASTM E1137 is also used in the United States. By far the most common devices used in industry have a nominal resistance of 100 ohms at 0 °C, and are called Pt100 sensors ('Pt' is the symbol for platinum). The sensitivity of a standard 100 ohm sensor is a nominal 0.00385 ohm/°C. RTDs with a sensitivity of 0.00375 and 0.00392 ohm/°C as well as a variety of others are also available.

Advantages Of RTD:

High accuracy Low drift Wide operating range Suitability for precision applications

Limitations Of RTD:

RTDs in industrial applications are rarely used above 660 °C. At temperatures above 660 °C it becomes increasingly difficult to prevent the platinum from becoming contaminated by impurities from the metal sheath of the thermometer. This is why laboratory standard thermometers replace the metal sheath with a glass construction. At very low temperatures, say below -270 °C (or 3 K), because there are very few photons, the resistance of an RTD is mainly determined by impurities and boundary scattering and thus basically independent of temperature. As a result, the sensitivity of the RTD is essentially zero and therefore not useful.

Compared to thermistors, platinum RTDs are less sensitive to small temperature changes and have a slower response time. However, thermistors have a smaller temperature range and stability.

2) THERMOCOUPLE:

One of the most common industrial thermometer is the thermocouple. A thermocouple is a device consisting of two different conductors (usually metal alloys) that produce a voltage, proportional to a temperature difference, between either ends of the two conductors. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a temperature gradient into electricity. They are inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self powered and require no external form of excitation. The main limitation with thermocouples is accuracy and system errors of less than one degree Celsius(C) can be difficult to achieve.

Any junction of dissimilar metals will produce an electric potential related to temperature. Thermocouples for practical measurement of temperature are junctions of specific alloys which have a predictable and repeatable relationship between temperature and voltage. Different alloys are used for different temperature ranges. Properties such as resistance to corrosion may also be important when choosing a type of thermocouple. Where the measurement point is far from the measuring instrument, the intermediate connection can be made by extension wires which are less costly than the materials used to make the sensor. Thermocouples are usually standardized against a reference temperature of 0 degrees Celsius; practical instruments use electronic methods of cold-junction compensation to adjust for varying temperature at the instrument terminals. Electronic instruments can also compensate for the varying characteristics of the thermocouple, and so improve the precision and accuracy of measurements.

Thermocouples are widely used in science and industry; applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes.

A thermocouple measuring circuit with a heat source, cold junction and a measuring instrument.

Principle of operation:

In 1821, the German–Estonian physicist Thomas Johann Seebeck discovered that when any conductor is subjected to a thermal gradient, it will generate a voltage. This is now known as the Thermoelectric effect or Seebeck effect. Any attempt to measure this voltage necessarily involves connecting another conductor to the "hot" end. This additional conductor will then also experience the temperature gradient, and develop a voltage of its own which will oppose the original. Fortunately, the magnitude of the effect depends on the metal in use. Using a dissimilar metal to complete the circuit creates a circuit in which the two legs generate different voltages, leaving a small difference in voltage available for measurement. That difference increases with temperature, and is between 1 and 70 microvolts per degree Celsius (µV/°C) for standard metal combinations.

The voltage is not generated at the junction of the two metals of the thermocouple but rather along that portion of the length of the two dissimilar metals that is subjected to a temperature gradient. Because both lengths of dissimilar metals experience the same temperature gradient, the end result is a measurement of the difference in temperature between the thermocouple junction and the reference junction.

Types Of Thermocouple:

Certain combinations of alloys have become popular as industry standards. Selection of the combination is driven by cost, availability, convenience, melting point, chemical properties, stability, and output. Different types are best suited for different applications. They are usually selected based on the temperature range and sensitivity needed. Thermocouples with low sensitivities (B, R, and S types) have correspondingly lower resolutions. Other selection criteria include the inertness of the thermocouple material, and whether it is magnetic or not. Standard thermocouple types are listed below with the positive electrode first, followed by the negative electrode.

K Type:

Type K (chromel {90 percent nickel and 10 percent chromium} – alumel {95% nickel, 2% manganese, 2% aluminium and 1% silicon}) is the most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C, chromel positive relative to alumel. It is inexpensive, and a wide variety of probes are available in its −200 °C to +1350 °C / -328 °F to +2462 °F range. Type K was specified at a time when metallurgy was less advanced than it is today, and consequently characteristics may vary considerably between samples. One of the constituent metals, nickel, is magnetic; a characteristic of thermocouples made with magnetic material is that they undergo a deviation in output when the material reaches its Curie point; this occurs for type K thermocouples at around 350 °C .

E Type:

Type E (chromel–constantan) has a high output (68 µV/°C) which makes it well suited to cryogenic use. Additionally, it is non-magnetic.

J Type:

Type J (iron–constantan) has a more restricted range than type K (−40 to +750 °C), but higher sensitivity of about 55 µV/°C. The Curie point of the iron (770 °C) causes an abrupt change in the characteristic, which determines the upper temperature limit.

N Type:

Type N (Nicrosil–Nisil) (nickel-chromium-silicon/nickel-silicon) thermocouples are suitable for use between −270 °C and 1300 °C owing to its stability and oxidation resistance. Sensitivity is about 39 µV/°C at 900 °C, slightly lower compared to type K.

Platinum Type Thermocouple:

Types B, R, and S thermocouples use platinum or a platinum–rhodium alloy for each conductor. These are among the most stable thermocouples, but have lower sensitivity than other types, approximately 10 µV/°C. Type B, R, and S thermocouples are usually used only for high temperature measurements due to their high cost and low sensitivity.

B Type:

Type B thermocouples use a platinum–rhodium alloy for each conductor. One conductor contains 30% rhodium while the other conductor contains 6% rhodium. These thermocouples are suited for use at up to 1800 °C. Type B thermocouples produce the same output at 0 °C and 42 °C, limiting their use below about 50 °C.

R Type:

Type R thermocouples use a platinum–rhodium alloy containing 13% rhodium for one conductor and pure platinum for the other conductor. Type R thermocouples are used up to 1600 °C.

S Type:

Type S thermocouples are constructed using one wire of 90% Platinum and 10% Rhodium (the positive or "+" wire) and a second wire of 100% platinum (the negative or "-" wire). Like type R, type S thermocouples are used up to 1600 °C. In particular, type S is used as the standard of calibration for the melting point of gold (1064.43 °C).

T Type:

Type T (copper–constantan) thermocouples are suited for measurements in the −200 to 350 °C range. Often used as a differential measurement since only copper wire touches the probes. Since both conductors are non-magnetic, there is no Curie point and thus no abrupt change in characteristics. Type T thermocouples have a sensitivity of about 43 µV/°C.

C Type:

Type C (tungsten 5% rhenium – tungsten 26% rhenium) thermocouples are suited for measurements in the 0 °C to 2320 °C range. This thermocouple is well-suited for vacuum furnaces at extremely high temperatures. It must never be used in the presence of oxygen at temperatures above 260 °C.

M Type:

Type M thermocouples use a nickel alloy for each wire. The positive wire (20 Alloy) contains 18% molybdenum while the negative wire (19 Alloy) contains 0.8% cobalt. These thermocouples are used in vacuum furnaces for the same reasons as with type C. Upper temperature is limited to 1400 °C. It is less commonly used than other types.

Advantages with thermocouples:

Capable of being used to directly measure temperatures up to 2600 oC. The thermocouple junction may be grounded and brought into direct contact with the

material being measured.

Disadvantages with thermocouples:

Temperature measurement with a thermocouple requires two temperatures be measured, the junction at the work end (the hot junction) and the junction where wires meet the instrumentation copper wires (cold junction). To avoid error the cold junction temperature is in general compensated in the electronic instruments by measuring the temperature at the terminal block using with a semiconductor, thermistor, or RTD.

Thermocouples operation are relatively complex with potential sources of error. The materials of which thermocouple wires are made are not inert and the thermoelectric voltage developed along the length of the thermocouple wire may be influenced by corrosion etc.

The relationship between the process temperature and the thermocouple signal (mill volt) is not linear.

The calibration of the thermocouple should be carried out while it is in use by comparing it to a nearby comparison thermocouple. If the thermocouple is removed and placed in a calibration bath, the output integrated over the length is not reproduced exactly.

RTDs vs Thermocouples:

Basic differences between RTDs and Thermocouples are given below:

RTD THERMOCUPLETemperature Requirement -200 to 500 °C -180 to 2,320 °CTime Response Slow FastSize (Sheath Diameter) 3.175 to 6.35 mm 1.6 mmAccuracy And Stability High Low

3) DIGITAL TEMPERATURE INDICATOR :

Under the category of temperature measuring instruments, we offer technically advanced digital temperature indicators and controllers. These are available with us in models DTIP and DTCP in which indicators or controllers are housed in flameproof casing. These modals are duly certified by CMRI as per gas group II A and II B of IS 2148. Some technical specifications of these measurement instruments are following:

Digital Temperature Indicator:

Temperature Range : -20OC to 600OC (J Type) Fe/Constant, -50OC to 1200OC (K Type) Cr/Alumel, -50OC to 199.9OC RTD (Pt 100), -50OC to 300OC RTD (Pt 100)

Display : 3 ', Oigil 12.5 mm hi Red LED Resolution : 1° C tor T/C and RTD - 50° C lo 199 9" C, 0.1°C(PI-100)RTD Accuracy : 0.5% of FSD /- 1count Power Supply : 230VAC ±10% 50 Hz Compensation : Automatic Cold junction compensation using solid state circuitry (built

in) over a range of 0°C to 5O°C for T/C type 3 wire system for RTD Open Sensor : Display shows "1" at MSD Overall Dimension : 96 X 96 X110 (D) mm Panel Cutout : 92 X 92 mm

CHAPTER-3

LEVEL MEASUREMENT

The height of the water column, liquid and powder etc., at the desired measurement of height between minimum level point to maximum level point is called level.

Level is measure with the help level gauges (sight glasses), other level meters etc.

1) ULTRASONIC LEVELTRANSMITTER:

Measures by Reflected Ultrasound

The Ultrasonic Level Transmitter allows simple and reliable non-contact level measurement of fluids in a tank, sump or other container. The microprocessor-controlled circuit generates a pulse that is transmitted from the transducer face. This pulse is reflected back from the surface of the liquid. The "round trip" transit time is then converted into the current output, which is directly proportional to the fluid level.

The current output (4-20mA) can power a load of up to 750 ohms.

SpecificationsElectrical specification:

Power 100 to 230 VAC ,50/60 HZ ,18 to 30 V DC Fuse Slow-Blow ,0.25 A , 250 VAC

Output

Repeatability 0.25 % of full rangeReasolution 3 mmRelay 2 form c (SPDT)

Contacts , Rated 5 A at 250 VAC ,Non inductive

Environment specification:

Location Indoor / OutdoorTemperature range -40 to 60 CRelative Humidity Type 6 , NEMA 6 , IP 67 EnclousureProcess Pressure 0.5 Bar

Mechanical specification:

Switching range Liquids : 0.25 to 5 mSolids : 0.25 to 3 m

Enclosure Terminal block ,Material : plastic

2) RADAR LEVEL TRANSMITTER:

The distance to the surface is measured by short radar pulses, which are transmitted from the antenna at the tank top. When a radar pulse reaches a media with a different dielectric constant, part of the energy is reflected back to the transmitter. The time difference between the transmitted and the reflected pulse is proportional to the distance, from which the level, volume and level rate, are calculated.

Environmental InfluenceTemperature Pressure Vapour Mist Product Density TurbulencesNo influence Slightly

dependentNo influence No influence Little influence

RADAR vs ULTRASONIC LEVEL TRANSMITTER:

RADAR ULTRASONICRANGE 1.5 to 780 inch. 1 ft to 20 ftMEASURE Liquid(also in highly

inflammable), solidLiquid

ACCURACY +/- 0.12 inch. Closer to 5mmPROCESS MOUNT ¾ inch. NPT 2 inch. NPTCERTIFICATION Standard: NEMA 6

Optional: Explosion proof, Zone 1

Intrinsically safe, Zone 0

CHAPTER-4

FLOW MEASUREMENT

Measurement of quantity which is flowing through close surface is known as flow.

Basically flow measurement is classified in three categories:

Instantaneous flow measurement Total flow measurement Mass flow measurement

1) MAGNETIC FLOW METER:

BASIC PRINCIPLE: Faraday's law of electromagnetic induction .

Magnetic flow meters use a magnetic field applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The potential difference is sensed by electrodes aligned perpendicular to the flow and the applied magnetic field.

The magnetic flow meter requires a conducting fluid and a non conducting pipe liner. The electrodes must not corrode in contact with the process fluid; some magnetic flow meters have auxiliary transducers installed to clean the electrodes in place. The applied magnetic field is pulsed, which allows the flow meter to cancel out the effect of stray voltage in the piping system.

A magnetic flow meter is a device that can measure a water-based or conductive volumetric flow with no moving parts.

2) VORTEX FLOW METER:

Another method of flow measurement involves placing a bluff body (called a shedder bar) in the path of the fluid. As the fluid passes this bar, disturbances in the flow called vortices are created. The vortices trail behind the cylinder, alternatively from each side of the bluff body.

The frequency at which these vortices alternate sides is essentially proportional to the flow rate of the fluid. Inside, atop, or downstream of the shedder bar is a sensor for measuring the frequency of the vortex shedding. This sensor is often a piezoelectric crystal, which produces a small, but measurable, voltage pulse every time a vortex is created. Since the frequency of such a voltage pulse is also proportional to the fluid velocity, a volumetric flow rate is calculated using the cross sectional area of the flow meter.

The frequency is measured and the flow rate is calculated by the flow meter electronics using

the equation where is the frequency of the vortices, the characteristic length of the bluff body, is the velocity of the flow over the bluff body, and is the Strouhal number, which is essentially a constant for a given body shape within its operating limits.

Benefits:

Maintenance-free due to fully welded sensor construction providing excellent stability and reliability

Contains three measuring points in one device with no extra equipment, installation or cabling costs

Saves downtime because of isolation valve, which makes an exchange of pressure sensor possible without interrupting the process

Easy installation because of Plug & Play Redundant system as a dual transmitter version is available

CHAPTER-5

PRESSURE MEASUREMENT

It is defined as amount of force applied to a surface & it is measured as force per unit area. The essentials of pressure measurement are encompassed in the above definitions & following observations.

1. Pressure is independent of direction. 2. Pressure is unaffected by the shape of confining boundaries.

Types of pressure

Gauge pressure: (Kg/cm2)

It is the difference between absolute and atmospheric pressure.

Absolute pressure: (Kg/cm2)

It is actual total pressure acting on a surface.

Vacuum pressure:

It is the pressure having value below zero.

Static pressure:

It is pressure at a particular point when the fluid is in equilibrium.

Different scales of pressure :

Pound per sq. in. (PSI) Pascal (Pa) Atmospheric pressure (atm) Pieze Torr mmHg kg/cm2

1) PRESSURE GUAGE:

Most standard dial type pressure gauges use a bourdon tube-sensing element generally made of a copper alloy (brass) or stainless steel for measuring pressures 15 PSI and above. Bourdon tube gauges are widely used in all branches of industry to measure pressure and vacuum. The construction is simple yet rugged and operation does not require any additional power source. The C- shaped or spirally wound bourdon tube flexes when pressure is applied producing a rotational movement, which in turn causes the pointer to indicate the measured pressure. These gauges are generally suitable for all clean and non-clogging liquids and gaseous media. Low pressure gauges typically use an extremely sensitive and highly accurate capsule design for measuring gaseous media from as low as 15 INWC to 240 INWC (10 PSI). Digital gauges use an electronic pressure sensor to measure the pressure and then transmit it to a digital display readout.

TYPES OF PRESSURE GUAGE:

1) Industrial gauges2) Commercial gauges3) Digital guages4) Process gauges5) Precision & Test gauges6) Low pressure gauges7) Specialty gauges

CALIBRATION:

Pressure gauges are either direct- or indirect-reading. Hydrostatic and elastic gauges measure pressure are directly influenced by force exerted on the surface by incident particle flux, and are called direct reading gauges. Thermal and ionization gauges read pressure indirectly by measuring a gas property that changes in a predictable manner with gas density. Indirect measurements are susceptible to more errors than direct measurements.

Dead-weight tester

McLeod

mass spec + ionization

2) DEAD WEIGHT PRESSURE TESTER:

A dead weight tester apparatus uses known traceable weights to apply pressure to a fluid for checking the accuracy of readings from a pressure gauge. A dead weight tester (DWT) is a calibration standard method that uses a piston cylinder on which a load is placed to make an equilibrium with an applied pressure underneath the piston. Deadweight testers are so called primary standards which means that the pressure measured by a deadweight tester is defined through other quantities: length, mass and time. Typically deadweight testers are used in calibration laboratories to calibrate pressure transfer standards like electronic pressure measuring devices.

CHAPTER-6

OTHER FIELD INSTRUMENTS

1) ORIFICE PLATES & FLANGES:

An orifice plate is a device used for measuring the volumetric flow rate. It uses the same principle as a Venturi nozzle, namely Bernoulli's principle which states that there is a relationship between the pressure of the fluid and the velocity of the fluid. When the velocity increases, the pressure decreases and vice versa.

An orifice plate is a thin plate with a hole in the middle. It is usually placed in a pipe in which fluid flows. When the fluid reaches the orifice plate, the fluid is forced to converge to go through the small hole; the point of maximum convergence actually occurs shortly downstream of the physical orifice, at the so-called vena contracta point. As it does so, the velocity and the pressure changes. Beyond the vena contracta, the fluid expands and the velocity and pressure change once again. By measuring the difference in fluid pressure between the normal pipe section and at the vena contracta, the volumetric and mass flow rates can be obtained from Bernoulli's equation.

There are three types of orifice plates:1) Concentric2) Eccentric3) Segmental

FLANGE: A protruding rim, edge, rib, or collar, as on a wheel or a pipe shaft, used to strengthen an object, hold it in place, or attach it to another object.

2) I to P CONVERTER:

"current to pressure" converter (I/P) which converts an analog signal (4-20 mA) to a proportional linear pneumatic output (3-15 psig). I To P Converter's purpose is to translate the analog output from a control system into a precise, repeatable pressure value to control pneumatic actuators/operators, pneumatic valves, dampers, vanes, etc.

CALIBRATION:

Zero adjustment of the unit is made by turning a screw that regulates the distance between the flapper valve and the air nozzle. Span adjustment is made by varying a potentiometer, which shunts input current past the coil. An integral volume flow booster provides adequate flow capacity, resulting in fast response time and accurate control.

3) R to I Converter:

These DIN rail mounted electronic modules have been designed to convert the position of a lever, tiller, steering wheel or azimuth control head into industry standard 4-20mA current signals.

FEATURES:

• Adjustable R/I-conversion circuit with span- and offset level calibration. • 10 Volts reference voltage to power the potentiometer. • The output signal is isolated from the power supply. • Large power supply range (24VDC±30%) • ‘Power-on’ indication (green LED). • Mounted on a DIN-rail according to EN50022.

BENEFITS:

Easy maintenance Longer service life Use friendly

4) STRAINERS & TRAPS:

STRAINER:One Spirax Strainer upstream of every trap, control valve, and flow meter can save you a bundle in annual maintenance and wear & tear costs. Available in Y or T type designs, our Strainers remove suspended grit from steam and condensate that would otherwise damage your downstream equipments with no additional pressure drop.

TRAP:

The duty of a steam trap is to discharge condensate while not permitting the escape of live steam.

No steam system is complete without that crucial component 'the steam trap' (or trap). This is the most important link in the condensate loop because it connects steam usage with condensate return.

A steam trap quite literally 'purges' condensate, (as well as air and other incondensable gases), out of the system, allowing steam to reach its destination in as dry a state/condition as possible to perform its task efficiently and economically.

The pressures at which steam traps can operate may be anywhere from vacuum to well over a hundred bar. To suit these varied conditions there are many different types, each having their own advantages and disadvantages. Experience shows that steam traps work most efficiently when their characteristics are matched to that of the application.

It is imperative that the correct trap is selected to carry out a given function under given conditions. At first sight it may not seem obvious what these conditions are.

They may involve variations in operating pressure, heat load or condensate pressure. Steam traps may be subjected to extremes of temperature or even water hammer.

They may need to be resistant to corrosion or dirt. Whatever the conditions, correct steam trap selection is important to system efficiency.

SELECTION OF STEAM TRAP:

Maximum steam and condensate pressures. Operating steam and condensate pressures. Temperatures and flow rates. Whether the process is temperature controlled.

5) SIGHT GLASSES:

A sight glass or water gauge is a transparent tube through which the operator of a tank or boiler can observe the level of liquid contained within.

Industrial observational instruments have changed with industry itself. More structurally sophisticated than the water gauge, the contemporary sight glass — also called the sight window or sight port — can be found on the media vessel at chemical plants and in other industrial settings, including pharmaceutical, food, beverage and bio gas plants. Sight glasses enable operators to visually observe processes inside tanks, pipes, reactors and vessels. The modern industrial sight glass is a glass disk held between two metal frames, which are secured by bolts and gaskets, or the glass disc is fused to the metal frame during manufacture. Borosilicate glass is superior to other formulations in terms of chemical corrosion resistance and temperature tolerance, as well as transparency. Fused sight glasses are also called mechanically pre-stressed glass, because the glass is strengthened by compression of the metal ring.

6) SWITCHES:

PRESSURE SWITCH:

A pressure switch is a form of switch that makes electrical contact when a certain set pressure has been reached on its input. This is used to provide on/off switching from a pneumatic or hydraulic source. The switch may be designed to make contact either on pressure rise or on pressure fall.

FLOW SWITCH:

A flow switch is a mechanical device that is switched on or off in response to the flow (or lack of flow) of a liquid or a gas. Flow switches are widely used in domestic air conditioning, heating and hot-water systems.

TEMPERATURE SWITCH:

A temperature switch is a switch that is responsive to temperature changes. Temperature switches generally are provided with a temperature responsive element which will open or close a switch when a predetermined minimum pressure or temperature is sensed by the responsive element.

CHAPTER-7

CoNTROL VALVES

What Is A Control Valve? A control valve is the final control element, which directly changes the flow rate of the manipulated variable.

Characteristics of control valves:

Quick Opening Linear Equal Percentage

BASIC PARTS OF CONTROL VALVE: Body Bonnet Actuator

TYPES OF ACTUATOR:

Direct Acting Reverse Acting

REVERSE-ACTING ACTUATOR

TYPES OF CONTROL VALVE:

Ball valve Globe valve Sliding gate valve Butterfly valve Diaphragm valve Venturi valve Pinch valve

CONCLUSION :

During preparation of this project, we had great experience with this company. The company provided us with a great platform to prove ourselves & our knowledge. The company was kind to us & they provided great help in terms of instruments, project feasibility.

We understood the Measurement of TEMPERATURE , LEVEL , FLOW , PRESSURE . We understood the working of different types of field instruments . We were also do the calibration of different types of indicators , Gauges & converters…