LE2 Flashcards
(127 cards)
1
Q
It is a push or pull upon an object resulting from the object’s interaction with another object.
A
Force
2
Q
What are the two categories of force?
A
↵
- Contact forces
- Forces resulting from action-at-a-distance
3
Q
This force results when the two interacting objects are perceived to be physically contacting each other.
A
Contact forces
4
Q
This type of force results even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation.
A
Action-at-a-distance force
(Non-contact force)
5
Q
Give 6 examples of contact forces
A
- Frictional force
- Applied force
- Spring force
- Air resistance force
- Normal force
- Tension force
6
Q
Give 3 examples of action-at-a-distance
A
- Gravitational force
- Electrical force
- Magnetic force
7
Q
MEMS is an abbreviation of …
A
Microelectromechanical system
8
Q
It is made by bonding strain gauges to a spring material.
A
Load Cell
9
Q
Strain gauges are placed on the part of the spring material where the strain will be the smallest.
TRUE or FALSE
A
FALSE
10
Q
What is the common metallic foil used for strain gauges?
A
Copper-Nickel alloy
11
Q
What is the relationship between the strain and resistance?
A
12
Q
It converts the load or weight acting on it into electrical signals.
A
Load transducer
13
Q
Strain gauges are load transducers.
TRUE or FALSE
A
TRUE
14
Q
The spring element of the load cells is in the shape of the parallelogram configuration. This configuration is known to be …
A
Roberval Mechanism
15
Q
The position of the load or weights placed on a scale that uses Roberval mechanism is very important.
TRUE or FALSE
A
FALSE
16
Q
What is the phenomenon which the material is deformed linearly based on force?
A
Hooke’s Law
17
Q
What are the advantages of load cells?
A
- Rugged and compact
- No moving parts
- Highly accurate
- Wide range of measurement
18
Q
What are the disadvantages of load cells?
A
- Mounting is difficult
- Calibration is hard
19
Q
What are the 8 types of load cells?
A
- Strain gauge
- Hydraulic
- Pneumatic
- Inductive and reluctance-based
- Magnetoelastic
- Piezoelectric
- Fibre-optic
- Resonant wire
20
Q
What is the most common type of load cell?
A
Strain gauge
21
Q
These are force-balance devices, measuring weight as a change in pressure of the internal filling fluid. The liquid (usually oil) has a preload pressure.
A
Hydraulic load cells
22
Q
It also operate on force-balance principle. The force is applied to one side of a diaphragm of flexible material and balanced by pneumatic pressure on the other side.
A
Pneumatic load cells
23
Q
These cells are based on the measurement of displacement of a ferromagnetic core caused to a force-summing device, like a diaphragm or bellows, by the applied force. The former changes the inductance of a solenoid coil due to the movement of its iron core while the latter changes the reluctance of a very small air gap.
A
Inductive and reluctance-based load cells
24
Q
This load cell is built from a stack of ferromagnetic laminations forming a load-bearing column. A set of primary and secondary transformer coils, oriented at 90o with each other, are wound through holes in the column.
A
Magnetoelastic load cell
25
This load cell produces a charge proportional to the force component specific to it.
Piezoelectric load cell
26
Like a wire strain gauge, a fibre-optic strain gauge can be fabricated using optical fibres. If this fibre-optic strain gauge is bonded to the elastic element of a load cell, an applied force will cause length changes in the optical fibre.
It uses monochromatic light to feed the gauges.
Fibre-optic load cells
27
It consists of a ferromagnetic wire that is excited into resonant transverse vibrations by a drive coil. A pick-up coil detects these vibrations. The resonant frequency is a measure of the tension of the wire and hence, applied force at that instant.
Resonant wire load cell
28
It is used to measure the differential pressure between two input points. It consists of a sensor, a transducer and a transmitter combined in a single device.
Differential pressure cell
29
What is the working principle of the differential pressure cell?
In DP cell a diaphragm is present which remains in normal condition when the forces on both sides of the diaphragm are equal. The unequal forces (pressure difference) create deformation in the diaphragm. By the extent of deformation, the differential pressure is calculated.
30
What are the two main types of DP cells?
* Pneumatic DP cell
* Electronic DP cell
31
It is the ratio of force to the area over which that force is distributed perpendicularly
Pressure
32
It is the pressure relative to the local atmospheric or ambient pressure
Gauge pressure
33
What is the unit of pressure and the scientist it was named after?
Pascal ; Blaise pascal
34
It is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of Earth (or that of another planet
Atmospheric pressure
35
What are the formulas of pressure?
P = F/A
P = ρgh
where:
ρ - density of liquid
g - gravitational acceleration
h - depth
36
It is the gauge pressure plus atmospheric pressure.
Absolute pressure
37
It derives pressure by the combination of a height differential of a liquid column and the density of the fluid within the liquid column.
Manometer
38
What are the different types of manometers?
* U-tube
* Inclined tube
* Well type
39
Fr this type of manometer, the pressure is always the height of fluid from one surface to the other regardless of the shape or size of the tubes
U-tube manometers
40
This type of the manometer tube is used for applications where accurate measurements of low pressure such as drafts and very low differential is required.
Inclined tube manometer
41
For this type of the manometer tube, the pressure is applied to a fluid well attached to a single indicating tube. as fluid moves down the well, the fluid is displaced into the smaller indicating leg of the manometer.
Well type manometer
42
It is an instrument used to measure linear, non-linear, mass or volumetric flow rate of a liquid or gas
Flow meter
43
It states that an increase in velocity of the fluid increases its kinetic energy and decreases its static energy. Therefore, restricting flow causes an increase in flowing velocity and also a drop in the static pressure.
Bernoulli principle
44
What are the 5 reasons for flow metering?
* Plant control, for product quality and safety reasons.
* Custody transfer, both interplant and selling to outside customers.
* Filling of containers, stock tanks and transporters.
* Energy, mass balancing for costing purpose and health monitoring of heat exchangers.
* Health monitoring of pipelines and on-line analysis equipment
45
It is defined as the volume of material passing a fixed point per unit of time, where the material is solid, liquid, or gas.
It has a formula of:
Q = V x A
where:
V – velocity of the fluid
A – cross-sectional area of the pipe
Flow rate
46
What is the formula for the rate of flow meter?
47
What the formula for the instantaneous flow rate?
48
What are the 2 different kinds of fluid flows?
* Laminar flow
* Turbulent flow
49
The fluid flow is rather smoothly parallel to the walls of the pipe. There is a linear relationship between the flow and pressure drop. It means very low flow rates and highly viscous fluids.
Laminar flow
50
Fluid flow is down the pipe but swirling within the flow. The pressure drop across a restriction is proportional to the square of the flow rate.
Turbulent flow
51
What are the two broad categories of flow sensors?
* Intrusive
* Non-intrusive
52
These are flow sensors that disturb the flow of the fluid that they are measuring
Intrusive flow sensors
53
These are flow sensors that do not disturb the flow of the fluid that they are measuring
Not-intrusive flow sensors
54
What are the measurement methods of flow classifications?
* Differential
* Velocity
* Displacement
* Mass
55
In this measurement method, the flow rate is determined by calculating the pressure difference (or pressure drop) as the final fluid flows through an obstruction such as an orifice plate
Differential measurement method
56
In this measurement method, the flow rate is determined based on the velocity of the fluid as it passes through a turbine
Velocity measurement method
57
In this measurement method, the flow rate is determined by measuring all the fluid used (VOLUME)
Displacement measurement method
58
In this measurement method, the flow rate is determined based on the total volume of the fluid that passes through the sensor
Mass measurement method
59
What are the three types of flow meters?
* Differential pressure meters
* Rotary meters
* Electrical flow meters
60
This type of flow meter has no moving parts, and it creates a pressure difference on either side of the device.
State the 4 kinds of this flow meter
Differential pressure flow meters
* Flow nozzle
* Dall flow tube
* Orifice plate
* Venturi tube
61
What is the disadvantage of differential pressure flow meters?
The obstruction causes a permanent loss of pressure in the flowing fluid
62
It is a type of differential flow meter where a metal disc with a concentric hole through it, placed in the flow
Orifice plate
63
It is a differential flow meter similar to the orifice but has better performance. Has a precision-engineered tube of a special shape, constricts the flow in some fashion and pressure sensors measures the differential pressure before and within the constriction.
Venturi differential pressure flow meter
64
It is a differential flow meter and it consists of two conical reducers inserted into the fluid-carrying pipe. It has a very similar internal shape to the Venturi, except that it lacks a throat
Dall flow tube differential pressure flow meter
65
Only gives the visual indication of flow rate, not used in automatic control. It consist of a tapered glass tube containing a float which takes up a stable position where its submerged weight is balanced by the upthrust due to the differential pressure across it
Rotameter
66
It is a common type of positive displacement flow meter. It consists of a slotted cylindrical piston moving cylindrical working chamber that has an inlet port and an outlet port. A peg on top of the piston causes a reciprocating motion of a lever attached to it, this is made to operate a counter
Rotary piston meter
67
Consists of a multi-bladed wheel mounted in a pipe along an axis parallel to the direction of fluid flow in the pipe
Turbine meters
68
What are the 3 different electrical flow meters?
clue: E V U
* Electromagnetic
* Vortex-Shedder
* Ultrasonic
69
This electrical flow meter is used for conductive fluids.
Electromagnetic
70
Who discovered vortex-shedding e-flow meter?
What is the working principle of vortex-shedding?
Theodore von Karman
71
This type of electrical flow meter is useful for measuring flow of corrosive fluids and slurries. Can be clamped externally onto existing pipe work rather than being inserted as an integral part of the flow line (safety advantage)
Ultrasonic
72
Two types of ultrasonic flow meter
* Doppler shift
* Transit time
73
It is a measure of how much a force acting on an object causes that object to rotate.
Torque
74
What is the formula of torque?
T = rFsin(Ø)
75
It is a device for measuring and recording the torque on a rotating system, such as an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or Cap Torque Tester. Static torque is relatively easy to measure.
Torque sensor or torque transducer or torque meter
76
The torque meter uses strain gauges to measure the torque.
TRUE or FALSE
TRUE
77
It is a device for measuring force, moment of force (torque), or power.
Dynamometer
78
What are the 3 classifications of dynamometer?
* Driving dynamometer
* Passive dynamometer
* Active dynamometer
79
It is a dynamometer that is used to determine the torque and power required to operate a driven machine such as a pump.
Driving dynamometer
80
It is a dynamometer that is designed to be driven.
Passive dynamometer
81
It is a dynamometer that can either drive or absorb.
Active dynamometer
82
The dynamometer has a "braking" torque regulator.
TRUE or FALSE
TRUE
83
What is the formula for the power in dynamometers?
P =* *Torque x angular velocity
P = F x V
84
What is the formula for power in dynamometer in terms of hp?
85
What is the formula for power in dynamometer in terms of kW?
86
Who introduced horsepower and invented the steam engine?
James Watt
87
What is the device used to measure temperature above 500°C?
Pyrometer
88
What is the device used to measure temperature below 500°C?
Thermometer
89
What are the 3 temperature transducers?
↵
* Thermocouple
* RTD
* Thermistor
90
This temperature measurement device uses the Seebeck effect that occurs when 2 different metals are joined at two junctions and held at two different temperatures.
Thermocouple
91
These are temperature sensors that exploit the predictable change in electrical resistance of some materials with changing temperature.
Positive temperature coefficient
RTD
92
What is the main type of wire used in RTDs?
Platinum
93
Special type of resistance sensor made from a small piece of semiconductor material.
Negative temperature coefficient.
It is highly sensitive and non-linear
Thermistors
94
What are the 10 applications of temperature sensors?
* Monitoring
* Portable Equipment
* CPU Temperature
* Battery Temperature
* Ambient Temperature
* Compensation
* Thermocouple Cold-Junction Compensation
* Control
* Battery Charging
* Process Control
95
This temperature measuring device is filled with either a liquid such as mercury or an evaporating fluid. Any rise in temperature produces expansion or evaporation of the liquid so the sensor becomes pressurized
Thermometers
96
In glass thermometers, Mercury is used for hot temperatures and colored alcohol for cold temperatures.
TRUE or FALSE
TRUE
97
This temperature measurement device is composed of two different metals joined together along its length. The two metals are sometimes configured as spiral or helix for compactness
Bimetallic thermometer
98
This temperature measurement device is similar to glass thermometers. It uses a bulb filled with liquid, and a pressure element such as a bourbon tube.
Filled bulb thermometer or filled system thermometer.
99
An apparatus for measuring high temperatures that uses the radiation emitted by a hot body as a basis for measurement.
Pyrometer
100
What are the 3 classifications of pressure sensors?
* Elastic pressure transducer
* Manometer method
* Electric pressure transducer
101
What are the 3 different kinds of elastic pressure transducer?
* Bourdon tube
* Diaphragm
* Bellows
102
This elastic pressure transducer is commonly used for measuring the gauge pressure of both gaseous and liquid fluids.
3 types of it are:
* C-type
* Spiral type
* Helical type
Bourdon tube
103
These are elastic pressure transducer that is used to measure gauge pressures over very low ranges.
2 types of it are:
* Metallic diaphragm
* Slack diaphragm
Diaphragm pressure transducer
104
This elastic pressure transducer is more sensitive than the bourdon type it resembles the accordion.
Bellows pressure gauges
105
What are the 5 types of electric pressure transducers?
* Strain gauge pressure transducers
* Capacitive pressure transducers
* Potentiometer pressure transducers
* Resonant Wire pressure transducers
* Piezeoelectric pressure transducers
106
It consists of interconnected components that is designed to control some physical quantity like temperature, pressure or speed.
Control system
107
In order to control a physical quantity, the control system must do what?
Sense the physical quantity
108
Then feedback of the control system uses _____ to determine the difference of the desired output with the actual output.
error
109
What are the two types of control system?
* Open-loop control systems
* Control-loop systems
110
This type of control system utilizes a controller to obtain the desired response.
Open-loop control system
111
This type of control system utilizes a feedback to compare the actual output to the desired output response.
Close-loop control system
112
What are the basic elements of an open-loop system?
Input - Control element - Correction element - Process - Output/Controlled variable
113
What are the basic elements of a closed-loop system?
Input/Comparison element - Control element - Correction element - Process element - Measurement element - Feedback
114
This control system element compares the reference value with the measure value and produces an error signal.
Comparison element in control-loop system
115
This control system element decides what action to take when it receives an error signal.
Control element
116
This control system element is used to produce a change in the process to remove the error and is often called an actuator,
Correction element
117
This control system element is the system of which a variable is being conrtolled
Process element
118
This control system element produces a signal related to the variable being controlled and provides the signal fed back to the comparison element to determine if there is an error.
Measurement element
119
It is the regulation of processes without human intervention.
Automatic control
120
What is the water triple point?
0.01°C or 273.16K
121
What are the mechanical ways to measure temperature?
↵
* Liquid in glass thermometer
* Bimetallic strip
* Pressure thermometer
* Gas filled thermometer
* Filled bulb thermometer
122
What is the working principle of bimetallic strip?
Two metals with different characteristics are joined together along its entire length. These metals elongate differently, thus, it curves.
123
What are the temperature classifications and its maximum surface temperature? (European)
↵
* T6 - 85
* T5 - 100
* T4 - 135
* T3 - 200
* T2 - 300
* T1 - 450
124
Newton's 1st law of motion states that...
An object at rest will stay at rest, and an object in motion will stay in motion at constant velocity, unless acted upon by an unbalanced force.
125
Newton's 2nd law of motion states that...
Force equals mass times acceleration.
126
Newton's 3rd law of motion states that...
For every action there is an equal and opposite reaction
127
