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