Design of Triplex Plunger Pump
Abdullah Al-JubranAli 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 EngineeringDepartment of Mechanical Engineering
Statement of Purpose
� To design a triplex plunger pump that can bemanufactured using locally available resources and manufacturing techniques
� To practice the application of computer-aided design program in the design of machines
College of EngineeringDepartment 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 EngineeringDepartment 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 EngineeringDepartment of Mechanical Engineering
Scope of Project
Designing of Triplex Plunger PumpDischarge 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 EngineeringDepartment 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 EngineeringDepartment of Mechanical Engineering
Triplex Pump Design GANTT Chart
College of EngineeringDepartment of Mechanical Engineering
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� Higher Pressure � Suitable for Chemicals� Good packing life
� Expensive� Good for slurries � Easier to maintain
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. Crankshaftb. Eccentric Sheavec. Crankshaft Support Bearingd. Eccentric Sheave Bearinge. Wrist Pinf. Wrist Pin Bearing g. Fluid End Plunger
Design Calculations
Criteria: Displacement: 24 li/minDischarge 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), barME = mechanical efficiency, %
At 24 liters/minute, 350 bar and typical efficiency of 88%,
(24 liters/min)(60min/hr)(1m3/1000liters)(350bar)
(36×0.88)kW =
kW = 15.91 kilowatts, or 21.33 Hp
Computation to determine Pump Speed and Plunger Spe ed
Q = A × m × n × s × 6× 10-8
Sp = s × n / 30,000
From Pump Handbook, 3 rd edition, pages 3.4, 3.6
Where Q = displacement, m 3/hSp = plunger speed, m/sA = cross-sectional area of plunger, mm 2
M = number of plungersn = rpm of pumps = 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
Plunger Bore, mm Plunger Stroke, mm
Pump Speed, rpm Plunger Speed, m/s
18
21 1,497 1.0522 1,429 1.0523 1,367 1.05
19
21 1,344 0.9422 1,283 0.9423 1,227 0.94
20
21 1,213 0.8522 1,158 0.8523 1,107 0.85
21
21 1,100 0.7722 1,050 0.7723 1,004 0.77
22
21 1,002 0.7022 957 0.7023 915 0.70
Table 1 Pump Speed at Different Plunger Bore and St roke
The obtained plunger speeds above are in accordance with the industry standard
Computation to determine Pump Required TorqueFrom Pump Handbook, 3 rd edition, page 3.8
M = p × 9.549 / nWhere M = pump torque, N·m
n = speed, rpmp = power, W
Plunger Bore, mm Plunger Stroke, mm
Pump Speed, rpm Torque, N·m
1821 1,497 10222 1,429 10623 1,367 111
1921 1,344 11322 1,283 11823 1,227 124
2021 1,213 12522 1,158 13123 1,107 137
2121 1,100 13822 1,050 14523 1,004 151
2221 1,002 15222 957 15923 915 166
a. Calculation to Determine Crankshaft Diameter
a. Calculation to Determine Crankshaft Diameter
Where D = shaft diameter, mmKt = shock and endurance factor applied to computed twi sting
moment (Table 14-2 Machine Design Data Book, 2 nd ed. page 14.18)
Mt = twisting moment or torque, N·mτyd = design yield stress, Pa
From Machine Design Data Book, 2 nd edition, page 14.3
16
πτyd
Kt × MtD =⅓× 1000
For rotating shafts with dynamic load, dynamic effe ct taken indirectly into consideration
The diameter of shaft subjected to simple torsion
From Machine Design Data Book, 2 nd edition, page 14.18
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
From Shigley's Mechanical Engineering Design, 8 th Edition, page 212
τmax = Sy / 2n
Where τmax = maximum shear stress, PaSy = yield stress, Pan = design factor
163.1415 × 68,666,666
1.5 × MtD =⅓
× 1000
Plunger Bore, mm
Plunger Stroke, mm
Pump Speed, rpm
Pump Torque, Nm
Computed Shaft
Diameter, mm
1821 1,497 102 22.422 1,429 106 22.823 1,367 111 23.1
1921 1,344 113 23.322 1,283 118 23.623 1,227 124 24.0
2021 1,213 125 24.122 1,158 131 24.423 1,107 137 24.8
2121 1,100 138 24.922 1,050 145 25.323 1,004 151 25.6
2221 1,002 152 25.622 957 159 26.023 915 166 26.4
Table 1: Computed Shaft Diameter at Different Plung er Bore and Stroke
b. Calculation to Determine Eccentric Sheave Diamet er
Sd2 = (s/2) + (D/2) + sw
Where Sd = eccentric sheave diameter, mms = plunger stroke, mmD = shaft diameter, mmsw = minimum sheave width, mm
- pre-selected to be 4.7625 mm (3/16 inch) to facili tate easywelding of the eccentric sheave to the shaft
Plunger Bore, mm
Plunger Stroke, mm
Computed Shaft Diameter, mm
Ecc. Sheave Diameter, mm
1821 22.4 53.022 22.8 54.323 23.1 55.7
1921 23.3 53.822 23.6 55.123 24.0 56.5
2021 24.1 54.622 24.4 56.023 24.8 57.3
2121 24.9 55.422 25.3 56.823 25.6 58.2
2221 25.6 56.222 26.0 57.623 26.4 59.0
Table 2: Eccentric Sheave Diameter at Different Sha ft Size
c. Calculation to Determine Strength of Eccentric S heave Weldment
Stresses in welded joints in torsion
τ" = Mr / J
Where τ” = shear or torsional stress, PaM = torsional moment, N·mr = distance from the centroid of the weld group to the point in the weld
of interest, mJ = second polar moment of area, m 4
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
J = 0.707hJu
By using the results above, the stress on the 3/16 inch fillet weld can be calculated.
(153Nm)(27mm/1000mm/m) ÷2
(0.707)(3/16in.)(1m/39.37in.)(2 ×3.1415)((27mm/1000mm/m) ÷2)3τ" =
τ" = 39,682,448 N/m2 or 39.7 MPa (5.473 ksi)
c. Calculation to Determine Crankshaft Bearing
Bearing Catalog Load Rating
C10 =1/a
FDLDnD60
LRnR60
Where C10 = catalog load rating, kN
FD = desired radial load, kNLD = desired life, hoursnD = desired speed, rev/minLR = rating life, hoursnR = rating speed, rev/mina = constant; a = 3 for ball bearings, a = 10/3 for roller bearings
For most bearing manufacturers LRnR60 = 106
C10 =1/a
FDLDnD60
106
Forces acting on the crankshaft bearing
Total maximum force acting on the bearing
Fb1 = 12
Fp2 + 34
Fp1
Fb1 = 54
Fp
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
= Fbmax
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 3: Maximum Bearing Load at Different Plunger Bore Sizes
Plunger Bore, mm18 19 20 21 22
FP, (kN) 8.91 9.92 11.0 12.12 13.30Fbmax, (kN) 11.13 12.40 13.74 15.15 16.63nD, (rpm) 1,497 1,344 1,213 1,100 1,002
LD, (hours) 5,000 5,000 5,000 5,000 5,000C10, (kN)
(ball bearing) 85.25 91.64 98.12 104.71 111.40
C10, (kN)(roller bearing) 69.55 75.03 80.61 86.31 92.11
Computed Shaft Dia, (mm) 23.1 24.0 24.8 25.6 26.4
Std. Shaft Dia., (mm) 25 25 25 30 30
AvailableBearing - - - - -
Table 4: Shaft Bearing Load Rating
Plunger Bore, mm18 19 20 21 22
FP, (kN) 8.91 9.92 11.0 12.12 13.30Fbmax, (kN) 11.13 12.40 13.74 15.15 16.63nD, (rpm) 1,497 1,344 1,213 1,100 1,002
LD, (hours) 5,000 5,000 5,000 5,000 5,000C10, (kN)
(ball bearing) 85.25 91.64 98.12 104.71 111.40
C10, (kN)(roller bearing) 69.55 75.03 80.61 86.31 92.11
Computed Shaft Dia, (mm) 23.1 24.0 24.8 25.6 26.4
Initial Std. Shaft Dia., (mm) 25 25 25 30 30
Adjusted Std. Shaft Dia., (mm) 30 30 30 30 30
AvailableBearing, SKF
NU 2306NJ 2306
NU 2306NJ 2306
NU 2306NJ 2306
- -
Table 4: Shaft Bearing Load Rating
Available SKF Bearing for the crankshaft
Plunger Bore, mm18 19 20
FP, (kN) 8.91 9.92 11.0nD, (rpm) 1,497 1,344 1,213
LD, (hours) 5,000 5,000 5,000C10, (kN)
(ball bearing) 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 60NA 4912
NKI 60/35
NKIS 60NA 4912
NKI 60/35
NKIS 60
Table 5: Eccentric Sheave Bearing Load Rating
e. Pump Driver Selection
e. Pump Driver Selection
e. Pump Driver Selection
Manufacturer Hp Speed, rpmEfficiency,
%Cost, $ Cat. No.
GE25 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 2,4801LE29313AC116AA3
TECO Westinghouse
25 1,200 91.7 3,438 N0256
25 1,200 93.0 4,456 EP0256
25 1,200 93.0 4,635 HH0256
Table 6: List of Applicable Drive Motors
e. Pump Driver Selection
Manufacturer Hp Speed, rpmEfficiency,
%Cost, $ Cat. No.
GE25 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 2,4801LE29313AC116AA3
TECO Westinghouse
25 1,200 91.7 3,438 N0256
25 1,200 93.0 4,456 EP0256
25 1,200 93.0 4,635 HH0256
Table 6: List of Applicable Drive Motors
Plunger Bore,mm
Plunger Stroke, mm
Speed, rpm Remarks
18
21 1,497Disregarded. Motor speed is only1,200 rpm.
22 1,429
23 1,367
19
21 1,344Disregarded. Motor speed is only1,200 rpm.
22 1,283
23 1,227
20
21 1,213 Disregarded. Motor speed is only 1,200 rpm
22 1,158 Selected Plunger Bore & Stroke
23 1,107 Disregarded. Not optimal.
21
21
Disregarded. No crankshaft bearing available.22
23
22
21
Disregarded. No crankshaft bearing available.22
23
Selected Plunger Bore and Stroke
Since the standard shaft diameter chosen is 30mm, a nd the eccentric sheave diameter is 60mm, the minimum sheave thickne ss, sw, is recalculated.
Sd2 = (s/2) + (D/2) + sw
From
sw =Sd - s - D
2
sw =60 - 22 - 30
2= 4 mm
f. Calculation to determine wrist pin size
AISI 1030 steel is chosen because of higher yield s trength than AISI 1020 steel.
Based on maximum shear stress theory, the maximum a llowable 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)
But since the cross-sectional area of the wrist pin is the same, therefore Aa=Ab, then,
Where A = cross-sectional area of wrist pin.
τmax = Fp / 2A = Fp ÷ 2(πdw2/4) ; dw = wrist pin diameter
By transposing the equation above
dw = (4Fp/2π τmax)1/2
4×11kN×1000N/kN
2×3.1415×86.7Mpa×106Pa/Mpadw =
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 loa d rating, C0, because the wrist pin
Basic static load rating C0
a. makes a slow oscillating or alignment movements u nder loadb. rotates under load at very low speed
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 bea ring with normal operations, S0=1. Since P0=11kN, then
C0 = 1×11k·N
C0 = 11k·N
From SKF catalogue, a drawn cup needle roller beari ng with C0=11.4k·N is available. The bearing designation is HN1010.
h. Bill of Materials
Item Description Specifications Quantity1 Crankshaft 30 mm O.D., AISI 1020 steel 1
2Crankshaft Suppport Bearing
SKF NU 2306 or NJ 2306 2
3 Eccentric Sheave 60 mm I.D., AISI 1030 steel 34 Eccentric Sheave Bearing SKF NKIS 60 35 Wrist Pin 10 mm O.D., AISI 1030 16 Wrist Pin Bearing SKF HN 1010 17 Motor GE M7549 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