College of Engineering
Department of Mechanical Engineering
Design of Triplex Plunger Pump
Abdullah Al-Jubran
Ali Al-Qahtani
Haitam Al-Mubarak
Project Advisor: Dr. Emad Tanbour
A Design Project Submitted in Partial Fulfillment
of the Requirements for the Course
Assessment III: Graduation Project
College of Engineering
Department of Mechanical Engineering
Statement of Purpose
To design a triplex plunger pump that can be
manufactured using locally available
resources and manufacturing techniques
To practice the application of computer-aided
design program in the design of machines
College of Engineering
Department of Mechanical Engineering
Table of Contents
Introduction
Scope of Project
Pumps Classification
Triplex Pump Basics/Concept
Calculations
Crankshaft Diameter
Bearings
Triplex Pump Prototype
College of Engineering
Department of Mechanical Engineering
Introduction
Triplex Plunger Pump
Positive Displacement Pump
Three Plungers in parallel
High-Pressure Low-Capacity Application
hydrostatic testing
water blasting
surface preparation
car washing
pipe and tube cleaning
oil drilling
College of Engineering
Department of Mechanical Engineering
Scope of Project
Designing of Triplex Plunger Pump
Discharge Pressure: 350 bar (5,076 psi)
Flow Rate:
24 li/min (6.3 gpm)
Crankshaft
Bearings
Material Selection
Fasteners
Making of Digital Prototype
College of Engineering
Department of Mechanical Engineering
Design Approach
Group Brainstorming
Gather Literatures from the web
Design Conceptualization
Identification of Critical Components
Sizing and Strength Calculations
Prototyping by CAD Solidworks
College of Engineering
Department of Mechanical Engineering
Triplex Pump Design GANTT Chart
Positive Displacement Pump versus Centrifugal Pump
Classification Diagram of Displacement Pumps
Classification Diagram of Displacement Pumps
Reciprocating Positive Displacement Pumps
1. Piston Pump
2. Plunger Pump
3. Diaphragm Pump
Good packing life
Higher Pressure
Suitable for Chemicals
Good for slurries
Easier to maintain
Expensive
Ways to Achieve Reciprocating Motion
1. Crankshaft with crank pin
2. Crankshaft with eccentric sheave or strap
Slider Crank Mechanism
The offset between the shaft center and eccentric
sheave center determines the pump stroke
Plunger Pump with Eccentric Sheave
Critical Components
a.
b.
c.
d.
e.
f.
g.
Crankshaft
Eccentric Sheave
Crankshaft Support Bearing
Eccentric Sheave Bearing
Wrist Pin
Wrist Pin Bearing
Fluid End Plunger
Design Calculations
Criteria:
Displacement:
24 li/min
Discharge Pressure: 350 bar
# of Plungers:
3
Computation to determine required power
kW = Q × Ptd / 36 × ME
Where Q = delivered capacity, m3/h
Ptd = differential pressure (discharge – suction), bar
ME = mechanical efficiency, %
At 24 liters/minute, 350 bar and typical efficiency of 88%,
kW =
(24 liters/min)(60min/hr)(1m3/1000liters)(350bar)
(36×0.88)
kW = 15.91 kilowatts, or 21.33 Hp
Computation to determine Pump Speed and Plunger Speed
From Pump Handbook, 3rd edition, pages 3.4, 3.6
Q = A × m × n × s × 6× 10-8
Sp = s × n / 30,000
Where Q =
Sp =
A=
M=
n=
s=
displacement, m3/h
plunger speed, m/s
cross-sectional area of plunger, mm2
number of plungers
rpm of pump
stroke of pump, mm
Preselected Plunger Bore and Stroke
Plunger Bore Size : 18, 19, 20, 21 and 22 mm
Plunger Stroke
: 21, 22, and 23 mm
Table 1 Pump Speed at Different Plunger Bore and Stroke
Plunger Bore, mm
18
19
20
21
22
Plunger Stroke,
mm
Pump Speed, rpm
Plunger Speed,
m/s
21
22
23
21
22
23
21
22
23
21
22
23
21
22
23
1,497
1,429
1,367
1,344
1,283
1,227
1,213
1,158
1,107
1,100
1,050
1,004
1,002
957
915
1.05
1.05
1.05
0.94
0.94
0.94
0.85
0.85
0.85
0.77
0.77
0.77
0.70
0.70
0.70
The obtained plunger speeds above are in accordance with the industry
standard
Computation to determine Pump Required Torque
From Pump Handbook, 3rd edition, page 3.8
Where
M
M
n
p
= p × 9.549 / n
= pump torque, N·m
= speed, rpm
= power, W
Plunger Bore, mm
18
19
20
21
22
Plunger Stroke,
mm
21
22
23
21
22
23
21
22
23
21
22
23
21
22
23
Pump Speed, rpm
1,497
1,429
1,367
1,344
1,283
1,227
1,213
1,158
1,107
1,100
1,050
1,004
1,002
957
915
Torque,
N·m
102
106
111
113
118
124
125
131
137
138
145
151
152
159
166
a. Calculation to Determine Crankshaft Diameter
a. Calculation to Determine Crankshaft Diameter
From Machine Design Data Book, 2nd edition, page 14.3
For rotating shafts with dynamic load, dynamic effect taken
indirectly into consideration
The diameter of shaft subjected to simple torsion
D =
πτyd
Where
⅓
16
Kt × Mt
× 1000
D = shaft diameter, mm
Kt = shock and endurance factor applied to computed twisting
moment
(Table 14-2 Machine Design Data Book, 2nd ed. page 14.18)
Mt = twisting moment or torque, N·m
τyd = design yield stress, Pa
From Machine Design Data Book, 2nd edition, page 14.18
From Shigley's Mechanical Engineering Design, 8th Edition, page 212
τmax = Sy / 2n
Where
τmax = maximum shear stress, Pa
Sy = yield stress, Pa
n
= design factor
Using AISI 1020 steel which has a yield strength of about 206 MPa,
and using a design factor of 1.5,
τmax = 206 MPa × 10^6 Pa/MPa
(2 × 1.5)
τmax = 68,666,666 Pa
16
D =
3.1415 × 68,666,666
1.5 × Mt
⅓
× 1000
Table 1: Computed Shaft Diameter at Different Plunger Bore and Stroke
Plunger Bore, Plunger Stroke,
mm
mm
18
19
20
21
22
21
22
23
21
22
23
21
22
23
21
22
23
21
22
23
Pump Speed,
rpm
Pump Torque,
Nm
1,497
1,429
1,367
1,344
1,283
1,227
1,213
1,158
1,107
1,100
1,050
1,004
1,002
957
915
102
106
111
113
118
124
125
131
137
138
145
151
152
159
166
Computed
Shaft
Diameter, mm
22.4
22.8
23.1
23.3
23.6
24.0
24.1
24.4
24.8
24.9
25.3
25.6
25.6
26.0
26.4
b. Calculation to Determine Eccentric Sheave Diameter
Sd
2
Where Sd
s
D
sw
= (s/2) + (D/2) + sw
=
=
=
=
eccentric sheave diameter, mm
plunger stroke, mm
shaft diameter, mm
minimum sheave width, mm
- pre-selected to be 4.7625 mm (3/16 inch) to facilitate easy
welding of the eccentric sheave to the shaft
Table 2: Eccentric Sheave Diameter at Different Shaft Size
Plunger Bore,
mm
18
19
20
21
22
Plunger Stroke,
mm
21
22
23
21
22
23
21
22
23
21
22
23
21
22
23
Computed Shaft
Diameter, mm
22.4
22.8
23.1
23.3
23.6
24.0
24.1
24.4
24.8
24.9
25.3
25.6
25.6
26.0
26.4
Ecc. Sheave
Diameter, mm
53.0
54.3
55.7
53.8
55.1
56.5
54.6
56.0
57.3
55.4
56.8
58.2
56.2
57.6
59.0
c. Calculation to Determine Strength of Eccentric Sheave Weldment
Stresses in welded joints in torsion
Where
τ"
= Mr / J
τ”
M
r
= shear or torsional stress, Pa
= torsional moment, N·m
= distance from the centroid of the weld group to the point in the weld
of interest, m
= second polar moment of area, m4
J
J
= 0.707hJu
For circular fillet welds
Ju
= 2 × π × r3
The distance from the centroid of the weld group to the point in the weld of interest,
r, can be taken as the radius of the shaft.
The force exerted by the plunger
Fp
= Pressure × Plunger Cross-Sectional Area
Example, 22mm plunger bore
Fp
= (350 bar) × (100KPa/bar) × (1000Pa/Kpa) × (1N/m2/Pa) × π ×
(22mm/1000mm/m)2/4
Fp
= 13,304 N
Maximum moment = Fp × (stroke/2). For 23mm stroke,
M
= 13,304 N × (23mm/1000mm/m) ÷ 2
M
= 153 N·m
By using the results above, the stress on the 3/16 inch fillet weld can be calculated.
(153Nm)(27mm/1000mm/m)÷2
τ"
=
τ"
= 39,682,448 N/m2 or 39.7 MPa (5.473 ksi)
(0.707)(3/16in.)(1m/39.37in.)(2×3.1415)((27mm/1000mm/m)÷2)3
c. Calculation to Determine Crankshaft Bearing
Bearing Catalog Load Rating
C10 = FD
LDnD60
1/a
LRnR60
Where C10 = catalog load rating, kN
FD
LD
nD
LR
nR
a
=
=
=
=
=
=
desired radial load, kN
desired life, hours
desired speed, rev/min
rating life, hours
rating speed, rev/min
constant; a = 3 for ball bearings, a = 10/3 for roller bearings
For most bearing manufacturers LRnR60 = 106
C10 = FD
LDnD60
106
1/a
Forces acting on the crankshaft bearing
Total maximum force acting on the bearing
Fb1 =
3F
1
Fp2 +
p1
4
2
Fb1 =
5 =F
F
bmax
4 p
Where Fp = Pressure × Plunger Cross-Sectional Area
Fp = (350 bar) × (100KPa/bar) × (1000Pa/Kpa) × (1N/m2/Pa) × π ×
(bore in mm/1000mm/m)2/4
Table 3: Maximum Bearing Load at Different Plunger Bore Sizes
Plunger Bore, mm
18
19
20
21
22
FP, k·N
8.91
9.92
11.0
12.12
13.30
Fbmax
11.13
12.40
13.74
15.15
16.63
Table 4: Shaft Bearing Load Rating
FP, (kN)
Fbmax, (kN)
nD, (rpm)
LD, (hours)
C10, (kN)
(ball bearing)
C10, (kN)
(roller bearing)
Computed Shaft
Dia, (mm)
Std. Shaft
Dia., (mm)
Available
Bearing
18
8.91
11.13
1,497
5,000
Plunger Bore, mm
19
20
9.92
11.0
12.40
13.74
1,344
1,213
5,000
5,000
21
12.12
15.15
1,100
5,000
22
13.30
16.63
1,002
5,000
85.25
91.64
98.12
104.71
111.40
69.55
75.03
80.61
86.31
92.11
23.1
24.0
24.8
25.6
26.4
25
25
25
30
30
-
-
-
-
-
Table 4: Shaft Bearing Load Rating
FP, (kN)
Fbmax, (kN)
nD, (rpm)
LD, (hours)
C10, (kN)
(ball bearing)
C10, (kN)
(roller bearing)
Computed Shaft
Dia, (mm)
Initial Std. Shaft
Dia., (mm)
Adjusted Std.
Shaft Dia., (mm)
Available
Bearing, SKF
18
8.91
11.13
1,497
5,000
Plunger Bore, mm
19
20
9.92
11.0
12.40
13.74
1,344
1,213
5,000
5,000
21
12.12
15.15
1,100
5,000
22
13.30
16.63
1,002
5,000
85.25
91.64
98.12
104.71
111.40
69.55
75.03
80.61
86.31
92.11
23.1
24.0
24.8
25.6
26.4
25
25
25
30
30
30
30
30
30
30
NU 2306
NJ 2306
NU 2306
NJ 2306
NU 2306
NJ 2306
-
-
Available SKF Bearing for the crankshaft
Table 5: Eccentric Sheave Bearing Load Rating
18
8.91
1,497
5,000
Plunger Bore, mm
19
9.92
1,344
5,000
20
11.0
1,213
5,000
68.20
73.31
78.50
C10, (kN)
(roller bearing)
55.64
60.02
64.49
Eccentric Sheave
Internal Dia., (mm)
30
30
30
Eccentric Sheave
Outside Dia., (mm)
60
60
60
Available Bearing,
SKF
NKIS 60
NA 4912
NKI 60/35
NKIS 60
NA 4912
NKI 60/35
NKIS 60
FP, (kN)
nD, (rpm)
LD, (hours)
C10, (kN)
(ball bearing)
e. Pump Driver Selection
e. Pump Driver Selection
e. Pump Driver Selection
Table 6: List of Applicable Drive Motors
Hp
Speed, rpm
Efficiency,
%
Cost, $
Cat. No.
25
1,200
91.7
2,312
S279
25
1,200
93.0
2,800
M7549
Baldor
25
1,200
93.0
5,090
ECP4111T
Siemens
25
1,200
91.7
2,480
1LE29313A
C116AA3
25
1,200
91.7
3,438
N0256
25
1,200
93.0
4,456
EP0256
25
1,200
93.0
4,635
HH0256
Manufacturer
GE
TECO
Westinghouse
e. Pump Driver Selection
Table 6: List of Applicable Drive Motors
Hp
Speed, rpm
Efficiency,
%
Cost, $
Cat. No.
25
1,200
91.7
2,312
S279
25
1,200
93.0
2,800
M7549
Baldor
25
1,200
93.0
5,090
ECP4111T
Siemens
25
1,200
91.7
2,480
1LE29313A
C116AA3
25
1,200
91.7
3,438
N0256
25
1,200
93.0
4,456
EP0256
25
1,200
93.0
4,635
HH0256
Manufacturer
GE
TECO
Westinghouse
Selected Plunger Bore and Stroke
Plunger
Bore,mm
18
19
20
21
22
Plunger
Stroke, mm
21
22
23
21
22
23
21
22
23
21
22
23
21
22
23
Speed, rpm
1,497
1,429
1,367
1,344
1,283
1,227
1,213
1,158
1,107
Remarks
Disregarded. Motor speed is only
1,200 rpm.
Disregarded. Motor speed is only
1,200 rpm.
Disregarded. Motor speed is only 1,200 rpm
Selected Plunger Bore & Stroke
Disregarded. Not optimal.
Disregarded. No crankshaft bearing available.
Disregarded. No crankshaft bearing available.
Since the standard shaft diameter chosen is 30mm, and the eccentric
sheave diameter is 60mm, the minimum sheave thickness, sw, is
recalculated.
From
Sd
2
= (s/2) + (D/2) + sw
sw =
sw =
Sd - s - D
2
60 - 22 - 30
2
= 4 mm
f. Calculation to determine wrist pin size
AISI 1030 steel is chosen because of higher yield strength than AISI
1020 steel.
Based on maximum shear stress theory, the maximum allowable shear
stress,
τmax = Sy / 2n
Where the yield strength, Sy, for 1030 steel is equal to 260 Mpa. Using a
design factor of 1.5,
τmax = 260 / (2×1.5) = 86.7 Mpa
f. Calculation to determine wrist pin size (cont’d)
Wrist pin will fail by shearing on sections a and b.
τmax = Fp / (Aa + Ab)
Where A = cross-sectional area of wrist pin.
But since the cross-sectional area of the wrist pin is the same, therefore
Aa=Ab, then,
τmax = Fp / 2A = Fp ÷ 2(πdw2/4) ; dw = wrist pin diameter
By transposing the equation above
dw = (4Fp/2π τmax)1/2
dw =
4×11kN×1000N/kN
2×3.1415×86.7Mpa×106Pa/Mpa
dw = 0.00899m or 8.99mm
The next preferred size is chosen which is 10 mm.
g. Computation to determine the wrist pin bearing
The bearing size is selected based on the static load rating, C0, because
the wrist pin
a. makes a slow oscillating or alignment movements under load
b. rotates under load at very low speed
Basic static load rating C0
C0 = S0 P0
Where C0 = basic static load rating, k·N
P0 = equivalent static bearing load, k·N
S0 = static safety factor
Based on SKF guideline, for non-rotating roller bearing with normal
operations, S0=1. Since P0=11kN, then
C0 = 1×11k·N
C0 = 11k·N
From SKF catalogue, a drawn cup needle roller bearing with C0=11.4k·N is
available. The bearing designation is HN1010.
h. Bill of Materials
Item
Description
1 Crankshaft
Crankshaft Suppport
2
Bearing
3 Eccentric Sheave
4 Eccentric Sheave Bearing
5 Wrist Pin
6 Wrist Pin Bearing
7 Motor
Specifications
30 mm O.D., AISI 1020 steel
Quantity
1
SKF NU 2306 or NJ 2306
2
60 mm I.D., AISI 1030 steel
SKF NKIS 60
10 mm O.D., AISI 1030
SKF HN 1010
GE M7549
3
3
1
1
1
j. Triplex Pump Solidworks Digital Prototype
j. Triplex Pump Solidworks Digital Prototype
j. Triplex Pump Solidworks Digital Prototype
j. Triplex Pump Solidworks Digital Prototype
i. Triplex Pump Solidworks Digital Prototype
j. Triplex Pump Solidworks Digital Prototype