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GASM 230 > GASM 230 Test 3 > Flashcards

GASM 230 Test 3 Flashcards

1
Q
  1. Name the sources of energy that are used to move the internal parts of an actuator. _
A

Pneumatic pressure, hydraulic pressure or electric current

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2
Q
  1. This type of actuator has instrument air supplied to both sides of the piston and uses the air/liquid to both open and close the valve.
A

Double Acting

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3
Q
  1. This type of actuator has instrument air supplied to only one side of the piston and uses a spring for energy on the opposite side.
A

Spring Return

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4
Q
  1. This type of actuator has a “fail-safe” position.
A

Spring Return

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5
Q
  1. This type of actuator is used in applications where the valve needs to fail in last position
A

Double Acting

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6
Q
  1. Name the five types of actuator groupings
A

Pneumatic, hydraulic, direct gas, gas over oil and electric

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7
Q
  1. These type of actuators use lower pressure compressed air or natural gas to generate the operating energy for the actuator.
A

pneumatic

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8
Q
  1. These type of actuators use high pressure gas to generate the operating energy for the actuator.
A

direct gas

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9
Q
  1. These type of actuators use an electric motor and some form of gear reduction to generate the operating energy for the actuator.
A

electric

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10
Q
  1. This type of actuator is typically used with valves requiring shorter travel such as globe valves
A

diaphragm

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11
Q
  1. The type of actuator is used where high levels of thrust is required to move the valve
A

piston

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12
Q
  1. Gate valves and globe valves require a _________ type actuator
A

linear

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13
Q
  1. Ball valves and plug valves require a _________ type actuator
A

rotary

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14
Q
  1. A direct acting actuator will fail _______ with a loss of supply pressure
A

open

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15
Q
  1. A reverse acting actuator will fail ______ with a loss of supply pressure
A

closed

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16
Q
  1. Name the two main styles of rotary actuators.
A

Rack-n-pinion and Scotch Yoke

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17
Q
  1. Butterfly and plug valves are typically used in ____________ applications.
A

on/off

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18
Q
  1. T/F In a rack and pinion actuator, the linear gear is known as the pinion.
A

False

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19
Q
  1. T/F An oversized valve actuator can cause damage to the stem of the valve.
A

True

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20
Q
  1. In the natural gas industry, _______ valves are typically used for throttling applications
A

ball and globe

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21
Q
  1. In the natural gas industry, ________ valves are typically used for on/off applications.
A

ball

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22
Q
  1. Identify the actuator types below:
A

Scotch Yoke
Piston
Diaphragm
Rack N Pinion

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23
Q
  1. How can restricted–capacity trim parts be helpful for changing flow conditions in an existing control valve?
A

Restricted capacity trim make it possible to select a valve body large enough for increased future flow requirements, but with trim capacity properly sized for present needs.

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24
Q
  1. Rack-and-pinion actuators are typically used for ________ applications
A

on/off

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25
Q
  1. T/F A controller is used to regulate process variables in an industrial process
A

True

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26
Q
  1. Name the three modes of control.
A

Proportional, Integral, Derivative.

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27
Q

3.T/F In a closed loop system, a sensor is used to measure the process variable and provide feedback to the controller.

A

True

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28
Q
  1. The desired or command value for the process variable is known as the _____.
A

Set Point

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29
Q
  1. _______ control is a control method that initiates a control response that is made in proportion to the magnitude and direction of the error amount between the set point and the measured value.
A

Proportional

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30
Q
  1. A proportional controller compares the set point with the process variable value and generates a(n)
A

Offset error

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31
Q
  1. What is the output signal equation for proportional control.
A

Kpxe

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32
Q
  1. The greater the value of the proportional gain factor Kp, the _____ is the response of the system
A

faster

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33
Q
  1. T/F If the proportional gain is too large for the process, the process will oscillate
A

True

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34
Q
  1. Proportional band is _______ proportional to gain
A

inversely

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35
Q
  1. T/F When sufficient gain is applied, the output will stabilize but will not quite reach the set point.
A

True

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36
Q
  1. When controller output exceeds its desired value, it is known as ________.
A

overshoot

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37
Q
  1. T/F Integral control is used when an unacceptable amount of offset occurs.
A

True

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38
Q
  1. Give an example of integrating (accumulating) a variables value with respect to time
A

Vehicle odometer

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39
Q
  1. T/F Integral control basically tells the controller output how fast to move
A

True

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40
Q
  1. T/F Integral control determines how much to compensate for the offset
A

True

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41
Q
  1. Once the process variable equals the setpoint, integral actions ___
A

stop operating

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42
Q
  1. Name the two ways to specify the degree of integral action.
A

Minutes or minutes per repeat

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43
Q
  1. Proportional plus integral control is also referred to as proportional plus ____ control.
A

reset

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44
Q
  1. When the amount of correction exceeds the capacity of the equipment and the setpoint still can’t be reached, the result is called integral ________.
A

windup

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45
Q
  1. T/F Too much integral action will not cause the control loop to oscillate
A

False

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46
Q
  1. T/F Derivative control is an expression of a variable’s rate of change with another variable
A

True

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47
Q
  1. Derivative control calculates the ratio of a variables change per ____________.
A

Unit of time

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48
Q
  1. T/F The purpose of the derivative action is to move the final control elements in a direction to counteract the rapid change by moderating the speed at which the process variable changes
A

True

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49
Q
  1. T/F Using derivative control is a good idea when the process variable has small, random, rapid changes in process variables.
A

False

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50
Q
  1. Rapid changes in a process variable is known as _______.
A

Noise

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51
Q
  1. Derivative control is most commonly used in _____ control loops.
A

temperature

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52
Q
  1. The adjustment of control parameters to achieve proper control is called ________.
A

Tuning

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53
Q
  1. What is the goal of tuning a PID control loop.
A

Adjust its output to move the process variable as quickly as possible to the set point, while minimizing overshoot, and the hold the variable steady at the set point without excessive output changes

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54
Q
  1. The time required to reach the setpoint is known as _______ time.
A

Response

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55
Q
  1. A control loop response that results in a process value that drives below the set point is known as ___________.
A

Undershoot

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56
Q
  1. To start tuning, one should begin with ___________ control.
A

proportional

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57
Q
  1. T/F Integral control is used when an unacceptable amount of offset occurs in a process with proportional control.
A

True

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58
Q

A device used for the control of fluid flow. It consists of a fluid retaining assembly, one or more ports between end openings and a movable closure member which opens, restricts or closes the ports).

A

Valve

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59
Q

A power operated device which modifies the fluid flow rate in a process control system. It consists of a valve connected to an actuator mechanism that is capable of changing the position of a flow controlling element in the valve in response to a signal from the controlling system

A

Control Valve

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60
Q

A a fluid powered or electrically powered device which supplies force and motion to a valve closure member.

A

Actuator

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61
Q

Is mechanically connected to a moving part of a final control element or its actuator, and automatically adjusts its output pressure to the actuator in order to maintain a desired position that bears a predetermined relationship to the input signal. The positioner can be used to modify the action of the valve (reversing positioner), extend the stroke/ controller signal (split range positioner), increase the pressure to the valve actuator (amplifying positioner) or modify the control valve flow characteristic (characterized positioner).

A

Positioner

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62
Q
  1. Name the four types of linear motion control valves.
A

Globe, gate diaphragm, pinch and clamp

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63
Q
  1. The three types of rotary motion control valves are ball, butterfly, and
A

Plug

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64
Q
  1. Name the three types of actuators. _
A

Pneumatic, electric and hydraulic

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65
Q
  1. A pneumatic input valve positioner has a ____________ output.
A

pneumatic

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66
Q
  1. This form of deadband is also known as slack that results from a temporary discontinuity between theinput and output of a device. An example is looseness of a mechanical connection. _
A

Backlash

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67
Q
  1. The rate of flow through a valve under stated conditions is known as _________________________.
A

Capacity

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68
Q
  1. T/F A process control loop where information from the process variable is continuously fed back to the controller to provide continuous automatic corrections to the process variable is known as an open loop.
A

False

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69
Q
  1. A device that operates automatically by use of an algorithm to regulate a controlled variable is known as a ___________________.
A

Controller

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70
Q
  1. The range through which an input signal can be varied without an observable change in the output signal is known as _______________.
A

Deadband

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71
Q
  1. The device that implements the control strategy determined by the output of the controller is known as the ______________________
A

Final Control element

72
Q
  1. T/F A force that opposes the motion between two surfaces is known as friction.
A

True

73
Q
  1. The ratio of between output change to input change is known as _________________.
A

Sensitivity

74
Q
  1. T/F The abbreviation for current to pressure input modules is known as E/P.
A

False

75
Q
  1. T/F A process control loop where information from the process variable is continuously not fed back to the controller is known as an open loop.
A

True

76
Q
  1. The closeness to which a curve relating two variables approximates a straight line is known as____________________________.
A

Linearity

77
Q
  1. The desired value of the process variable being controlled is known as ____________________.
A

Set point

78
Q
  1. The internal components of a valve that modulate the flow of the controlled fluid is known as___________.
A

Trim

79
Q
  1. For the globe valve trim characteristics below, label the equal percentage, linear, and quick opening
    characteristics.
A

top curve - Quick Opening
Middle flat- Linear
low curve - Equal percentage

80
Q
  1. At the 50% of rated travel, the quick opening valve trim provides _____% of maximum flow.
A

80

81
Q
  1. At the 50% of rated travel, this valve trim provides 18% of maximum flow. _______________.
A

Equal percentage

82
Q
  1. This characteristic of this valve trim typically has the same % of maximum flow as the % of rated travel. (i.e. 30% travel = 30% flow) __________________________________
A

Linear

83
Q
  1. A part of the trim that surrounds the closure member and provides flow characterization is the_______________________.
A

Cage

84
Q
  1. For the valve trims below, identify the equal percentage, linear, and quick opening cages
A

Linear
Equal Percentage
Quick Opening

85
Q
  1. The area of contact between the closure member and its mating surface that establishes valve shut-off is known as the _____________.
A

seat

86
Q
  1. T/F Flangeless control valves are common to rotary-shaft control valves.
A

True

87
Q
  1. The flow control orifice of a control valve is known as a ________________________.
A

Port

88
Q
  1. The most common type of segmented ball valve is known as a ___________________ ball.
A

V Notch

89
Q
  1. A part of the valve assembly used to seal against leakage around the valve disk or stem is known as _______________________________________.
A

Packing

90
Q
  1. A control valve that moves to a closed position when the actuating supply gas source fails is known as a ________________ valve.
A

Fail-closed

91
Q
  1. A control valve that moves to an open position when the actuating supply gas source fails is known as a ________________ valve.
A

fail-open

92
Q
  1. A control valve that stays in its last position when the actuating supply gas source fails is known as a ________________ valve.
A

fail-safe

93
Q
  1. This constant known as Cv is related to the geometry of a valve for a given travel and represents the number of US gallons/minute of 60 Degree water that will flow through a valve with a 1 psi pressure
    drop is the _______________________________.
A

Flow Coefficient

94
Q
  1. The quantity of fluid passing through a valve when the valve is in the fully closed position with specified pressure differential and temperature is known as______________________________.
A

Seat leakage

95
Q
  1. Name the six ANSI Leakage Class Designations for Control Valve Seat Leakage.
A

I
II
III
IV
V
VI

96
Q
  1. This ANSI Leakage Class Designations requires no testing
A

I

97
Q
  1. This ANSI Leakage Class Designation requires 45 -60 psig of pressure of air or water between 50 – 125 ◦F applied to the inlet with outlet open to the atmosphere and a maximum allowable leakage of 0.01% of rated capacity. _____________
A

IV

98
Q
  1. This ANSI Leakage Class Designation requires 45 -60 psig of pressure applied to the inlet with outlet open to the atmosphere and a maximum allowable leakage given in bubbles per minute____________.
A

VI

99
Q
  1. A valve with a Class VI ANSI Leakage Class Designation with a 1” has an allowable seat leakage of ______ bubbles per minute.
A

1

100
Q
  1. A valve with a Class VI ANSI Leakage Class Designation with a 2” has an allowable seat leakage of ______ bubbles per minute.
A

3

101
Q
  1. Why are compressed air systems not used at gas pipeline valve settings and measuring stations for instrument supply air?
A

The remoteness of the valve settings and measuring stations makes them impractical to install pneumatic systems

102
Q
  1. Name some of the operating problems that unprocessed natural gas can cause in pneumatic actuated valves
A

Dirty or wet gas will clog pneumatic controllers and wet air or gas will freeze in the winter months

103
Q
  1. What are the two components that are used to dry the gas in dryer canisters? _
A

Silica gel and activated charcoal

104
Q
  1. What are the two typical pressure outputs for an instrument supply system?
A

35psig spit for actuators requiring 6-30 psig supply pressure and 20 psig for actuators requiring 3-15 psig supply pressure

105
Q
  1. Why are catalytic heaters used in instrument supply systems?
A

High inlet pressures (>1,000 psig) due to the Joule-Thomson effect of 7° F temperature reduction occurs for every 100 psig drop and they are flameless

106
Q
  1. In a moisture indicator, this color indicates that the desiccant is saturated and needs changed out.
A

Pink Color

107
Q
  1. Why do some instrument supply systems have duplicative filters and regulators? _
A

So that flow can continue should maintenance be required on one of the filters or regulators or as a standby backup.

108
Q
  1. What function does a pneumatic controller perform?
A

Use regulated gas supply pressure to control the operation of mechanical devices, such as valves

109
Q
  1. Name two process variables that can be controlled with a pneumatic controller.
A

Levels and Pressures

110
Q
  1. What are the two typical output pressure ranges of pneumatic controllers?
A

3-15 psi or 6-30 psi

111
Q
  1. Name the three types of process signal measuring elements that are can be used with the controller.
A

Bellows, Helical bourdon tube and spiral bourdon tube

112
Q
  1. What part of the controller shows the scale range of the controller?
A

Dial

113
Q
  1. The __________ measures the difference between the measurement pointer and the setting index position.
A

Differential linkage

114
Q
  1. The __________ allows the operator to manually operate the pneumatic controller
A

Auto/manual transfer system

115
Q
  1. Name the part of the controller that adjusts the output pressure when the controller is set to “Manual”.
A

Regulator

116
Q
  1. What part of the pneumatic controller shows the true value of the process variable? _
A

Measurement Pointer

117
Q
  1. To understand what is happening in a process, what three pieces of information that is available on a pneumatic controller should a technician should look at?
A

The Set point index, the measurement pointer and the output pressure to the valve actuator

118
Q
  1. To make an adjustment to the minimum range of the pneumatic controller, you should use the _____ adjustment
A

Zero

119
Q
  1. To make an adjustment to the maximum range of the pneumatic controller, you should use the _____ adjustment.
A

Span

120
Q
  1. Where are positioners typically mounted on linear sliding stem control valves?
A

On the side-yoke or top casing of the pneumatic actuator

121
Q
  1. Name three reasons for using a valve positioner
A

Increase control system resolution, Allow for split ranging, one controller for 2 valves. Overcome seation friction in rotary valves

122
Q
  1. Name the three types of positioners.
A

Pneumatic, Analog I/P Postioners and Smart or Digital Positioners

123
Q
  1. An I/P positioner uses __________________ instead of air supply as the input signal.
A

electrical current

124
Q
  1. The electronic signal conversion is ________ in a smart positioner
A

digital

125
Q
  1. Valve hysteresis throughout the valve stroke in a control valve configuration without a positioner is __________ than a control valve configuration with a positioner.
A

Significantly higher

126
Q
  1. Name five reasons why instrumentation and accessories are added to a control valve. _
A

Improve process control, improve safety for the process or personnel, improve valve performance or speed of response, Monitor or verify the valve responsiveness and diagnose potential valve issues

127
Q
  1. Positioners are typically used when valves are used in ____________ applications.
A

throttling

128
Q
  1. An I/P positioner uses a _________ mA DC signal to modulate the control valves.
A

4 to 20

129
Q
  1. T/F With a digital valve positioner, the microprocessor enables diagnostics and two-way digital communication to simplify setup and troubleshooting.
A

True

130
Q
  1. Provide two examples of data feedback that is provided by the microprocessor to the control system.
A

Run, analyze, and store diagnostic tests as well allowing the positioner to communicate with the control system via a digital signal

131
Q
  1. Name two common protocols used by digital positioners.
A

HART communication and FOUNDATION fieldbus

132
Q
  1. This communication protocol uses a digital signal superimposed over a 4 to 20 mA DC control signal.
A

HART communication

133
Q
  1. An I/P transducer converts a current input into a proportional _________________ output.
A

Pressure

134
Q
  1. What is the purpose of a volume booster?
A

Used to provide additional pneumatic output capacity to a valve assembly

135
Q
  1. A properly sized control valve should operate at between ________ percent open at the maximum required flow rate
A

60 to 80

136
Q
  1. A properly sized control valve should operate at not less than ____ % open at the minimum required flow.
A

20

137
Q
  1. T/F Commonly, the control valve is too large for the application.
A

True

138
Q
  1. With an oversized valve, small changes in valve position will cause _____ changes in flow.
A

large

139
Q
  1. T/F Valve sizing and selection for control valves in gas service must include noise calculations.
A

True

140
Q
  1. Inherent characteristic of a control valve represents the relationship between valve flow capacity and _______ when there are no system effects involved.
A

Valve opening

141
Q
  1. T/F The majority of fluid process systems include a significant amount of pipe and other pressure consuming elements such as tees, elbows and valves.
A

True

142
Q
  1. The installed characteristic of an equal percentage valve in a system with a lot of pipe is not linear but has a slight ____ shape
A

S

143
Q
  1. A process system with a lot of piping should use a control valve with a(n) _____________ characteristic.
A

Equal percentage inherent

144
Q
  1. A process system that has very little pipe should use a control valve with a(n) _______ characteristic.
A

Linear inherent

145
Q
  1. T/F A standard port ball valve has a flow path that is the same size as the valve’s pipe size
A

False

146
Q
  1. How many shafts are used to support the ball in a Fisher V250 ball valve?
A

two

147
Q
  1. What is/are the name(s) of the shaft(s) called in Question #2 above? _
A

follower shaft and drive shaft

148
Q
  1. What are the two types of soft seal designs for ball valves?
A

Single and double

149
Q
  1. The seal face is a ball valve is protected from contact with the flowing media by a
A

Metal seal protector ring

150
Q
  1. If you have a ball control valve with bidirectional flow, you should select a ______ seal design.
A

double

151
Q
  1. T/F Advantages of a ball control valve include high flow capacities and low pressure drop across the valve.
A

True

152
Q
  1. Name the three basic styles of butterfly valves.
A

Conventional, lined and high-performance

153
Q
  1. Pressure drop across a butterfly valve is _________ the pressure drop through a globe valve.
A

less than

154
Q
  1. T/F A wafer style butterfly valve requires care in installation because they must be perfectly centered between two flanges
A

True

155
Q
  1. T/F A conventional butterfly valve does not provide a tight shutoff
A

True

156
Q
  1. What feature does a high performance butterfly valve have that a conventional butterfly valve does not have?
A

An offset (eccentric) disk used in the construction which allows for pressure-assisted seals

157
Q
  1. How is the sealing action accomplished in a high performance butterfly valve?
A

Allows the process pressure behind the seal to provide the force for the seal to press against the sealing edge of the disk

158
Q
  1. Name the two basic types of plug valves. _
A

Lubricated and non-lubricated

159
Q

Correct position to install a valve?

A

Upside up

160
Q
  1. T/F Flanges, piping and equipment must line up square and true with the valve without putting undue stress on the valve.
A

True

161
Q
  1. T/F When gas or steam flows through a control valve, noise is generated.
A

True

162
Q
  1. T/F Noise from a control valve may be loud enough to cause hearing damage to those who are nearby.
A

True

163
Q
  1. When gas flows past a restriction in the control valve, the velocity _______.
A

increases

164
Q
  1. T/F If the pressure drop across the control valve is high enough, the turbulence will generate sound waves which will move down the pipe with some coming through the pipe wall
A

True

165
Q
  1. Name the two strategies for reducing control valve noise.
A

Source Control and Path Control

166
Q
  1. Define “pressure drop staging” noise reduction.
A

Instead of taking then entire pressure drop in one step, the pressure drop is divided up into two or more steps.

167
Q
  1. Doing something to the valve to make it less noisy is known as ____ control.
A

source

168
Q
  1. Small reductions in velocity have a small effect on reducing valve noise.
A

True

169
Q
  1. For the “flow division” noise reduction method, every time you double the number of openings, you reduce the noise by ___dBA.
A

3

170
Q
  1. Define “flow division” noise reduction
A

Instead of flowing through a single opening, the flow is divided up so that it pass through several openings in parallel

171
Q
  1. T/F Using the smaller opening associated with “flow division” actually shift the noise to higher frequencies.
A

True

172
Q
  1. Globe control valve using flow division with one stage noise trim can achieve noise reduction of ___dBA noise reduction.
A

10 to 15 dBA

173
Q
  1. Multiple stage flow dividers can achieve ____ dBA noise reduction.
A

15 to 25

174
Q
  1. Name the three types of path control method that can be used to control noise.
A

Distance, heavy wall pipe and thermal or acoustic insulation

175
Q
  1. Thicker pipe walls attenuate ____ noise as it passes through the pipe wall compared to thinner pipe walls.
A

more

176
Q
  1. Name a disadvantage of using heavy wall pipe to control noise.
A

Can become cost prohibitive as it is expensive

GASM 230 (2 decks)

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