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Chad's Flashcards

1
Q

What does the first number on the C-pump reference number indicate?

A

diameter of the discharge port in inches

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2
Q

What does the second number on the C-pump reference number indicate?

A

diameter of the suction port in inches

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3
Q

How does a C-pump work?

A

It employs a centrifugal force to develop pressure change to move a liquid.

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4
Q

What are the steps of the function of the C-pump?

A

When the pump is full of fluid and the impeller begins rotating, the fluid follows the impeller blades. As the impeller speed increases, the centrifugal force throws the fluid toward the outer edge of the impeller blade.

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5
Q

What happens when the impeller moves faster?

A

The faster the fluid moves outward and the greater the flow rate.

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6
Q

What is necessary for a C-pump to move fluid?

A

It must be full of fluid

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7
Q

Pumps convert _____ energy from an engine or electric motor into ______ energy by pushing fluid into the system

A
  1. mechanical

2. hydraulic

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8
Q

What are the two main families of pumps?

A
  1. positive displacement pumps

2. non-positive displacement pumps

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9
Q

What defines a positive displacement pump?

A

Whatever enters the pump inlet is forced out the outlet port

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10
Q

How do positive displacement pumps add energy?

A

by increasing the pressure on the fluid in the pump

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11
Q

A positive displacement pump delivers a specific amount of _______, revolution, or cycle to the system.

A

fluid per stroke

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12
Q

How is pump output on a positive displacement pump?

A

constant, regardless of pressure, with the exemption of changes in efficiency

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13
Q

What are the 3 best know positive displacement pumps?

A
  1. gear pumps
  2. vane pumps
  3. piston pumps
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14
Q

What defines a non positive displacement pump?

A

Do not have a positive seal between the inlet and outlet ports.

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15
Q

For non-positive displacement pumps, what are pressure capabilities a function of?

A

drive speed

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16
Q

For a non-positive displacement pump, what happens to output as resistance is increased?

A

output is reduced

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17
Q

When are non-positive displacement pumps mainly used?

A

fluid transfer in systems where the only resistance is created by weight of the fluid and by friction

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18
Q

Non-positive displacement pumps ____ energy by _____ the speed of the fluid inside the pump

A

add

increasing

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19
Q

What are the 7 main components of a centrifugal pump?

A
  1. casing or volute
  2. impeller and wear plates
  3. shaft
  4. bearings
  5. bearings frame and stuffing box
  6. seals or packing
  7. power source
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20
Q

What is the C-pump casing/housing called?

A

Volute

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21
Q

What does the volute convert the velocity energy into?

A

pressure

and also gives the fluid direction.

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22
Q

What two factors determine volute design?

A
  1. maximum output rates and pressures

2. sense of pump rotation or the intended rotation direction

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23
Q

How can the rotation of the volute be determined?

A

by watching the direction of rotation of the input shaft.

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24
Q

What are volute frames typically made of?

A

cast iron
therefore they should never be welded or brazed because the heat will call the volute to become distorted, warped, or cracked.

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25
Volute Casing:Flowrate | Volute Casing:Pressure
directly | indirectly
26
What is the impeller?
1. the rotating element in the centrifugal pump through with liquid passes. 2. energy is imparted to the liquid in the impeller
27
What are the 3 types of impellers?
1. open 2. semi-open 3. closed
28
What is an example of an open impeller?
RA 4X5 | RA 5X6
29
What types of fluids do open impellers typically move?
dirty
30
What flow rates do open impellers have?
high
31
What discharge pressures do open impellers have?
Low
32
What is an example of a closed impeller?
RB 2X3 | Guinard
33
What type of fluid do closed impellers move?
Clean
34
What flow rate to closed impellers typically have?
Low
35
What discharge rates do closed impellers typically have?
High
36
What 3 ways can the direction of impeller rotation be changed?
1. reversing the volute 2. installing the opposite impeller 3. . switching the hydraulic lines to the motor
37
What is the purpose of wear plates?
provide a wear surface and a seal between the casing and the impeller.
38
Where are the wear plates located?
on either side of the impeller and are generally solid steel plates
39
What should be replaced when installing a new impeller?
wear plates
40
What is the correct clearance between the impeller and the wear plates?
1/16 inch
41
True or False. Wear rings serve the same function as wear plates
True
42
Wear rings are used in centrifugals that contain ______ impellers.
closed | such as RB 2X3X11
43
What are wear rings typically made of?
brass
44
What is the role of the centrifugal pump shaft?
supports the impeller and is itself supported by bearings
45
The shaft transmits the torque from a _______ source to the _______ where it is subject to radial, axial, and torque loads.
power source | impeller
46
True or False. Radial loads are due to the impeller weight and pressure differences around the impeller when it is moving
True
47
What is the function of the bearing?
supports the shaft
48
What happens if the shaft is not supported and held with a precision?
The impeller will touch the casing and the packing will have a shorter life span.
49
Where is the seal or packing contained in the stuffing box located?
between the stationary casing casing and the rotating shaft.
50
What is the role of the stuffing box and packing material of a c-pump?
provide an area to seal against leakage from the pump and along the shaft.
51
The packing material must counter ______
the effects of the fluid trying to escape along the shaft when it is being pumped at pressure.
52
What are the 3 things that packing material must have?
1. a low coefficient of friction 2. an absence of abrasive effect on the shaft 3. an ability to prevent excessive leakage
53
What are the two main types of packing materials?
1. "jam-type" (used for self-lubricating pumps) | 2. rubber oil seals known as"automatic/mechanical type"
54
Describe "jam-type"
Rope packing that is jammed into the stuffing box and adjusted periodically by tightening the nuts on a gland to preserve its sealing ability
55
T or F. Rope packing in a c-pump acts like a seal around the moving shaft, but only to the extent that it throttles leakage.
True
56
Where does lubrication come from in rope packing?
a slight leak through the packing or, in emergencies, from a saturant in the packing itself.
57
What happens if the packing is dry?
it will start to run hot, harden, and score the shaft.
58
What happens if the packing is over-tightened?
the packing will soon burn up and score the shaft, so it is important to pack the stuffing box properly
59
Which ring does most of the work in rope packing?
The ring next to the gland in jam-type packing does most of the work because the mechanical pressure on the gland is greater than the friction along the rod.
60
What are the 3 common rope packing ring materials?
1. asbestos rope 2. teflon-coated rope 3. graphite-coated rope
61
How do the mechanical seals work?
liquid pressure in the seal chamber force the mating faces together and provide a thin film of lubricant between them.
62
Which types of pumps use mechanical seals?
RA 4X5 RA 5X6 RB 2X3X11
63
True or False. Neither "jam type" seals or the oil seals should ever be over-tightened.
True
64
3 types of lubrication
1. self-lubricated 2. oil 3. grease
65
What does the method of lubricating the packing largely depend on?
the nature of the liquid being pumped as well as the pressure in the stuffing box
66
What happens when the pumping stuffing box pressure is above the atmospheric pressure?
the pumped liquid itself will lubricate the packing. The pumped liquid must be allowed to leak or flow through the stuffing box to cool the packing.
67
What are examples of self-lubricated systems?
RB 2X3 and the LPM pumps
68
What is cavitation?
a
69
True or false. For pumps that have a lower discharge pressure, an enclosed lubrication system is needed to help prevent cavitation
True
70
Which is the best lubrication system?
oil-lubricated systems
71
What two things are extremely detrimental to packing?
1. inadequate lubrication | 2. heat generation
72
True or false. An air-operated pump (Alemite pump) delivers lubricating oil to a divider block which in turn delivers oil equally to each packing set.
True
73
Which pumps use oil lubrication systems or air over oil packing lube systems
RA 4x5 and RA 5x6
74
Grease lubrication
not very efficient. used for pumps with a high discharge rate and low pressure. example is the RB 10x12
75
What are the 4 main power sources for centrifugal pumps?
1. Diesel Drives 2. Electric Drives 3. Power Take-Off (PT0)
76
Which type of pumps typically use diesel-driven C-pumps?
small pressurizer skids and blenders
77
Which type of C-pumps use electric drives?
Offshore RMX and Batch Mixers (RA45-RA56)
78
What are power take-offs?
drive mechanisms coupled directly from the transmission of the engine
79
Which type of C-pumps typically use hydraulic drives?
cement pump units, recirculating mixers, and batch mixers (RA45-RA56)
80
What centrifugal pumps are used by Schlumberger?
RB 2x3, RA 4x5, RA5x6, 10x12
81
Which pumps use open impellers?
RA45 RA56 LaBour 5x6
82
What is the RA45 pump used for?
pressuring and make-up pump | *used for both sand and cement pumping operations
83
What type of seals do the RA45 pumps use?
mechanical oil seals
84
What is the main application of the LaBour Pump 5x6
a Tornado mixer
85
What are the pumps with closed impellers used for?
low pressure mixing pumps

Centrifugal Pumps (2 decks)

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