TABLE OF CONTENT
INTRODUCTION
Scope 5
General Instrumentation Consideration 6
Pneumatic Power Supplies 7
Important of Instrumentation Control for Unit Operation 8
Process Variable Measurement Instrument 9
DEFINITIONS 11
NOMENCLATURE 13
THEORY
A) Pressure Measurement 15
Height of a Liquid Column 15
Elastic-Element – Bourdon Tube, Bellows and Diaphragm 17
i) Bourdon Tubes 17
ii) Bellows 19
iii) Diaphragm 21
Electrical Method -Electrical Pressure Transducers 22
i) Strain Gauges 22
B) Level Measurement 23
Gauge Glass 23
Chain or Tape Float Gauges 25
Lever and Shaft Float Gauges (Ball Gauge) 25
Displacer 27
Pressure Gauge 30
Electrical Level Gauges 32
Magnetic Gauge 33
C) Temperature Measurement 34
Thermocouples 35
i) Thermocouples Sensor 37
Resistance Thermometers (RTD) 38
Bimetal Thermometers 39
D) Signal Transmitter 40
E) Recorders and Indicators 41
F) Control System 41
G) Control Modes and Controllers 42
On-off Controller 42
Proportional Controller 43
Proportional Plus Integral (PI) 44
Proportional Plus Derivative Mode (PD) 45
Proportional Plus Integral Plus Derivative (PID) 45
APPLICATION
Example Case 1: Level Control Schematic Drawing for Fractionation 47
Tower Bottom.
Example Case 2: Pressure Control Schematic Drawing for Fractionation 48
Overhead Drum.
Example Case 3: Temperature Control Schematic for Bottom Fractionation 49
Tower
REFEREENCES
50
SPECIFICATION DATA SHEET
Instrument Specification Data Sheet Revision 01
51
CALCULATION SPREADSHEET
U-Tube Manometer Calculation Spreadsheet Revision 01 52
Level- Pressure Gauge Calculation Spreadsheet Revision 01 53
Level- Pressure Gauge (HTG) Calculation Spreadsheet Revision 01 54
Temperature- Bimetal Thermometer Calculation Spreadsheet Revision 01 55
LIST OF TABLE
Table 1: Properties of Typical Type of Thermocouples. 36
Table 2: Metals Properties for RTDs. 39
LIST OF FIGURE
Figure 1: Simple Instrument Model 6
Figure 2: U- Shape Tube Manometer 16
Figure 3: Inclined U-Tube Manometer 17
Figure 4: C-spring Bourdon-Tube Pressure Gauge 18
Figure 5: Spring-Loaded Bellows 19
Figure 6: Unopposed Bellows 20
Figure 7: Beam Balance Sensor Bellows 20
Figure 8: Diaphragm Pressure Elements 21
Figure 9: The Wheatstone bridge 22
Figure 10: Reflex Gauge Glass 24
Figure 11: Transparent Gauge Glass 24
Figure 12: Chain and Tape Float Gauge 25
Figure 13: External Ball Float Level Device for Emergency and Alarm Services 26
Figure 14: Internal Ball Float Level Device 27
Figure 15: Displacer Level Measuring Device 28
Figure 16: Quantities of a solid body immersed into a liquid 28
Figure 17: Typical pressure gauge level measurement system 30
Figure 18: HTG Level Measurement System 31
Figure 19: Bubble Tube Level Measurement 32
Figure 20: Conductivity Level Device – Low and High Level Alarm Indication 33
Figure 21: Magnetic Gauge Level Measurement Device 34
Figure 22: Thermal EMF, E, of Commonly Used Thermocouples as a Function of Temperature 35
Figure 23: Typical Thermocouple circuit 36
Figure 24: Industrial Thermocouple Assembly 37
Figure 25: Ceramic Platinum RTD. 38
Figure 26: Flat Strip Bimetal Thermometer 39
Figure 27: Controller Modeling Diagram 43
Figure 28: Response of Step Change in Disturbance with Tuned P, PI, PID, and
Non-controlled. 46
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