D3 Study Flashcards
1
Q
Vehicle load damage to buried pipes dissipates _____ ft below the surface, and the _____ the trench, the less possibility of pipe damage from vehicles loads.
A
2 to 5, narrower
2
Q
When casing is used for under a rail Road or Highway, the casing pipe diameter should be _____ Larger than the outside diameter of the Watermain bells
A
2 to 8 in.
3
Q
What does the service line size primarily depend upon?
A
Elevation difference between main and highest building point served
4
Q
Standards for tapping ______ Have been withdrawn by AWWA
A
Asbestos cement
5
Q
This type of valve should be use so that restricted flow and increase pumping cost should not occur
A
Air relief valve
6
Q
What type of valve is used in distribution system where the main is not buried very deep?
A
Horizontal gate valve
7
Q
A valve that should not be operated frequently because it requires too much time to open and close is a
A
Gate valve
8
Q
This type of valve provides low volume flow without the need for opening the main valve
A
Bypass valve
9
Q
What type of valve produces high head loss even when fully opened
A
Globe valve
10
Q
This type of valve is similar to globe valves except their desks are usually maintained against the seat by a spring
A
Pressure relief valve
11
Q
_____ head is a measurement of the _____ distance from the hydraulic grade line to the energy great line
A
Velocity, vertical
12
Q
What are the two main elements that affect the efficient delivery of water
A
Water losses and energy usage
13
Q
The most significant and useful head measurement from an operating standpoint is
A
Pressure
14
Q
A distribution system performance category would include
A
Reliability
15
Q
Friction had loss is one of the ______ head losses to calculate. The formula most commonly used is the _____ formula.
A
Simplest , Hazen Williams
16
Q
A high-capacity pump will need to overcome ____ head that may be many times greater than the _____
A
Friction, increase in flow rate
17
Q
The pump centerline is represented by a _____ line drawn through the center of the pump, and it is important because it is the _____
A
Horizontal, reference line from which pump head measurements are made
18
Q
All the power of the electric current driving the motor is used to drive the pump. However, some of the current is used to overcome _____ within the motor, and some current is lost to the conversion of _____ to _____
A
Friction, electrical energy, mechanical energy
19
Q
What is wire to wire efficiency
A
Motor efficiency times pump efficiency
20
Q
What type of valve allows for the opening and closing speeds of an actuator to be adjusted
A
Needle valve
21
Q
What can help a water utility avoid using large pumps?
A
Elevated storage tanks
22
Q
What type of storage most likely not require an emergency pump?
A
Elevated tank
23
Q
Where are air relief valves used?
A
On the discharge side of a well pump and at the high points in transmission pipelines
24
Q
The fire insurance underwriters recommend high value districts should have a minimum pipe sizes
A
8 to 12 inches
25
The fire insurance underwriters recommend that residential areas should have a minimum pipe sizes of
6 to 8 inches
26
What is the most likely problem that oversize pipes cause?
Water quality problems
27
A pipe friction loss depends on a combination of factors, including
Flow velocity, pipe roughness, and pipe diameter
28
Pipe sizes can be determined using the friction loss calculation from the
Hazen William formula
29
The distribution system design should include equal emphasis on _____ and _____
Quantity, quality
30
General factors to be considered for selection of pipe include service connections. What is the main factor that should be considered for service connections
Pressure
31
What inoculant is added to molten iron that makes it strong enough in producing ductile iron pipe
Magnesium
32
If a pressure test in a particular location indicates a wide variation from night to peak day use, then the
System is being stressed
33
What type of pipe has high tensile strength and low cost and is good hydraulically when lined but is subject to general corrosion if installed unprotected in a corrosive environment?
Steel pipe
34
What type of joint utilizes a bolted, segmental, clamp type, mechanical coupling with a housing that encloses a U-shaped rubber gasket?
Grooved joints
35
What type of pipe is easy to fabricate and special configurations, relatively easy to transport and install, and is resistant to shock load and has the ability to bend to some degree but can collapse due to partial vacuum from rapid emptying
Steel pipe
36
What type of pipe is generally easy to install, easy to ship, easy to handle, and generally of low cost but susceptible to buckling under a vacuum?
PVC pipe
37
The use of _____ has decreased remarkably because of structural difficulties causing premature pipe failures
Polybutylene pipe
38
What type of piping material is corrosion resistant and light weight and has a low installation cost but has low molecules of elasticity
Fiberglass pipe
39
Water utilities that purchase their water during off-peak hours will usually pay much less. The rate charge for this water is often called
Off peak charge
40
A water system may need a large amount of storage if it depends on a single, long transmission mean as it’s only water source. This type of system usually provides storage equal to at least _____ of water use
1 day
41
____ demand can account for as much as _____ of the total capacity of a storage system
Fire, 50%
42
What type(s) of large water storage is (are) usually equipped with an adjacent pumping system that can be used in an emergency to pump water to the distribution system?
Standpipes
43
Most elevator storage tanks are constructed out of
Steel
44
What type of concrete storage tank is constructed by first installing an inner concrete core wall that establishes the reservoirs form
Circular, prestressed concrete tank
45
In cold climates, any exposed risers on multicolumn tanks are generally _____ In diameter or larger to allow for freezing around the inside edge of the riser
6 feet
46
And inside ladder will not be installed in elevated tanks that are
In cold climates
47
The coatings inside a tank must not cause _____ and must meet _____
Taste and odor, NSF International standards
48
Where water tanks regularly form ice inside, they should be protected from corrosion by using sacrificial anodes that are ____ the tank
Welded to a submerged structure in
49
Tanks that form ice inside should have
Nothing exposed inside that can be damaged by the ice
50
If sodium hypochlorite is used to disinfect the storage tank, the total value of the entire tank should have a free chlorine residual of at least _____ after the proper detention time
10 mg/L
51
If after the appropriate detention time I disinfected tank test positive for _____, It must be disinfected again and re-tested until at least _____ Consecutive sample test safe
Total coliform, two
52
What should be inspected on an altitude valve that feels an elevated tank
Opening and closing speed to prevent water hammer
and
make sure valve is letting enough water in to fill the tank
53
In a Venturi meter, the difference in pressure before the constriction and at the throat can be measured, and the change in pressure is
Proportional to the square of the velocity
54
Why is the design of the suction piping so important
To allow sufficient flow
To minimize pressure losses
55
The joints on large sized suction piping should be _____, and for smaller sized pipes, the joints should be _____
Flanged, screwed or flanged
56
In the pump characteristic curves, three curves are use that relate _____, _____ and _____
Head to discharge, efficiency to discharge, power to discharge
57
A vertical turbine pump is a type of
Velocity pump
58
A velocity pump will convert the velocity and pressure of the water to _____ and ____ because of the _____
Low velocity, high pressure, shape of the volute or shape of the diffuser vanes
59
What type of pump generally develops very high heads and has low flow capacities
Radial flow pump
60
What type of pump move the water parallel to the axis of the pump rather than being thrown outward
Axial flow pump
61
What type of pumps are manufactured in a wide range of sizes and designs, combining efficiency with high speeds to create the highest heads obtainable from velocity pumps?
Vertical turbine pumps
62
The close fitting impeller of this type of pump prohibits any pumping of solid sediment, such as sand, find grit, and silt
Vertical turbine pump
63
For monitoring flow at _____ And for control purposes, meters must be provided with _____ that are _____ to the flow rate
Remote locations, pulses or an electrical outlet, proportional
64
What is a disadvantage of using a vertical turbine pump
High repair cost
65
Many older plants have instrumentation that runs on pneumatic air with an operating range of _____, And newer plants run with electrical transmission using either current or voltage, the most common being ____
3 to 15 psig, 4-20 mA direct current (DC)
66
What type of transmission allows signals to pass in only one direction
Simplex
67
Large pumps should be started with the discharge valve _____. If a foot valve does not exist and no head is on the suction side of the pump, it should be primed using a _____.
Closed, vacuum pump or ejector operated with Steam, air, or water
68
If a pump with a check valve on the discharge side experiences water hammer when shut down suddenly, what can be installed to absorb this pressure shot
Relief valves
69
What is a pump design called if it has the pump unit mounted on the shaft of the motor that drives the pump with the motor bearings supporting the impeller
Close coupled
70
Double suction pumps will use impellers
Only of the closed design
71
In some centrifugal pumps, only one wear is mounted _____; Others utilize two wear rings, _____
In the case; one on the impeller and one in the case
72
The clearance between the rotating impeller wear ring and the stationary case wear ring is usually
0.010 to 0.020 inches
73
A double suction pump shaft and impeller is secured together by _____. An end-suction pumps impeller is mounted on the end of the shaft and held in place by a.
A key, key nut
74
If a pump operates under a high suction head, what should be used
A mechanical seal
75
Mechanical seals are designed so that they can be ____ balanced and have an operating life to as much as _____
Hydraulically, 20,000 hours
76
A pump that develops a partial vacuum on the suction side must be fitted with (a) close clearance _____ between the _____ and the suction passage of the pump to maintain lubrication, cooling, and the flushing fluid at the _____
Bushing, seal, seal
77
EPANET is a computer program that performs extended period simulation of _____ and _____ Behavior within pressurized pipe networks
Hydraulic, water quality
78
Hydraulic modeling capabilities can compute friction head loss using the
Hazen William’s formula
79
What type of actuators will operate by a limit switch for on and off and can be fitted with controls that can be adjusted to leave the valve partially open for use in throttling
Electric actuators
80
What type of actuators would use electric solenoid valves to operate the valve in each direction
Hydraulic actuators
81
What type of actuators need sufficient reserve capacity to provide continuous operation after a power failure
Pneumatic actuators
82
Although pneumatic actuators can be used on _____, they are more common on _____.
Isolation valves, control valves
83
How does the valve work in a standard compression hydrant
The valve closes with the water pressure against the seat
84
How does the valve work on a toggle hydrant
Valve closes horizontally
85
If the hydrant needs to be throttled, one of the nozzles should be fitted with a _____ and the hydrant valve funny opened
Gate valve
86
In large motors both the _____ are electromagnets
Rotor and stator
87
There must be at least two poles in a motor, but there can be more depending on how the ______ is made and how the _____ are wired and connected
Stator, current-carrying coils
88
A four-pole motor has synchronous speed of
1800 rpm’s
89
What is the starting current on a motor called
Locked rotor current
90
What type of motor has a high starting torque and a high starting current
Capacitor start motor
91
What type of motor has a starting current that is seldom greater than normal full load current
Wound rotor induction motor’s
92
What development got us away from manually starting large motors that posed a considerable danger of shock and electrocution
Magnetic starters
93
Where extreme accuracy is required, what type of level sensor can be fitted with a special adaptation that is a level transmitter called a stage recorder?
Float mechanism
94
What type of level sensor is commonly use a strain gauge sensor to convert their changes into an electrical signal
Bubbler tubes and diaphragm
95
Electronica signal transmissions use
Electrical current or voltage signals
96
These analog systems can be used only for short distances
Current and voltage
97
These analog systems can be used only for long distances
Post duration modulation and variable frequency
98
What is it called when signals are allowed to be passed in both directions simultaneously
Pulse duration modulation
99
What is an example of an automatic control device
Thermostat
100
What type of control requires ability to predict outfit
Feed forward control
101
This type of control is open loop
Feed forward control
102
What type of control reacts to an error and adjust to correct it
Feedback control
103
What type of control is a closed loop
Feedback control
104
Which type of meter should have a strainer installed ahead of the flow into it to protect it from sediment and other objects in the water
Compound meter
105
This type of water meter is used wear daily flow is usually low, but on occasion like in an emergency the flow has to be very high
Detector check meter
106
In most cases, the meter size is installed ___ The service line
One size smaller
107
If large capacity and close accuracy at low flows is important, what type of meter is best?
Compound type meter
108
What type of meter has an inductive coil mounted on a wall or on the cover of the meter pit and where the meter reader gets near the interactive coil to obtain the reading
Scanning type unit
109
What does system metering accomplish?
Helps in administrating water rights
Helps determine pump in pipeline capacity
Helps engineer and design of water system improvements
110
Propeller meters are primary use for the measurement of
Main lines
111
Proportional meters are _____ but are _____. However, they have _____
Relatively accurate, difficult to maintain, little friction loss
112
Microbial incidence due to cross connections are most likely caused by
Sewage
113
The casing for a tunnel under a railroad or highway is usually made out of
Steel or concrete pipe
114
Water quality considerations need to be included in the design of pipeline networks. By integrating these concepts with _____ and ___ Requirements, many future water quality problems can be avoided
Volume, pressure
115
The ___ can get soil worked up from the bottom, and the ______ can probably bring the curb stop and ____ up with it if the box is pulled from the ground, for example by a backhoe
Arc pattern base, Minneapolis style curb stops in boxes, service line
116
Some ___ have _____ Requiring the maintenance of drawings and records so that the utility can respond to emergencies, personal injuries, or damage to underground utility services during excavation’s
States, statues or regulations
117
Water supply should try to reference their comprehensive maps to the _____ for range and section lines
State coordinate system
118
Water distribution system operators will occasionally deal with _____. These _____ should be referenced to _____
Plan and profile drawings, engineer in drawings, section lines or property lines
119
What is another name for a transmitter
Transducer
