Triplex Pump Design.pdf
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Transcript of Triplex Pump Design.pdf
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Design of Triplex Plunger Pump
Abdullah Al-JubranAli Al-Qahtani
Haitam Al-Mubarak
Project Advisor: Dr. Emad TanbourA Design Project Submitted in Partial Fulfillment
of the Requirements for the Course
Assessment III: Graduation Project
College of EngineeringDepartment of Mechanical Engineering
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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
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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
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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
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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
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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
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Triplex Pump Design GANTT Chart
College of EngineeringDepartment of Mechanical Engineering
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Positive Displacement Pump versus Centrifugal Pump
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Classification Diagram of Displacement Pumps
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Classification Diagram of Displacement Pumps
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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
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Ways to Achieve Reciprocating Motion
1. Crankshaft with crank pin
2. Crankshaft with eccentric sheave or strap
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Slider Crank Mechanism
The offset between the shaft center and eccentric sheave center determines the pump stroke
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Plunger Pump with Eccentric Sheave
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Critical Componentsa. Crankshaftb. Eccentric Sheavec. Crankshaft Support Bearingd. Eccentric Sheave Bearinge. Wrist Pinf. Wrist Pin Bearing g. Fluid End Plunger
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Design CalculationsCriteria: Displacement: 24 li/min
Discharge Pressure: 350 bar# of Plungers: 3
Computation to determine required powerkW = Q Ptd / 36 ME
Where Q = delivered capacity, m3/hPtd = 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)(360.88)kW =
kW = 15.91 kilowatts, or 21.33 Hp
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Computation to determine Pump Speed and Plunger Speed
Q = A m n s 6 10-8Sp = s n / 30,000
From Pump Handbook, 3rd edition, pages 3.4, 3.6
Where Q = displacement, m3/hSp = plunger speed, m/sA = cross-sectional area of plunger, mm2M = 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
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Plunger Bore, mm Plunger Stroke, mm
Pump Speed, rpm Plunger Speed, m/s
1821 1,497 1.0522 1,429 1.0523 1,367 1.05
1921 1,344 0.9422 1,283 0.9423 1,227 0.94
2021 1,213 0.8522 1,158 0.8523 1,107 0.85
2121 1,100 0.7722 1,050 0.7723 1,004 0.77
2221 1,002 0.7022 957 0.7023 915 0.70
Table 1 Pump Speed at Different Plunger Bore and Stroke
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The obtained plunger speeds above are in accordance with the industry standard
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Computation to determine Pump Required TorqueFrom Pump Handbook, 3rd edition, page 3.8
M = p 9.549 / nWhere M = pump torque, Nm
n = speed, rpmp = power, W
Plunger Bore, mm Plunger Stroke, mm
Pump Speed, rpm Torque, Nm
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
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a. Calculation to Determine Crankshaft Diameter
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a. Calculation to Determine Crankshaft Diameter
Where D = shaft diameter, mmKt = 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, Nmyd = design yield stress, Pa
From Machine Design Data Book, 2nd edition, page 14.3
16piyd
Kt MtD = 1000
For rotating shafts with dynamic load, dynamic effect taken indirectly into consideration
The diameter of shaft subjected to simple torsion
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From Machine Design Data Book, 2nd edition, page 14.18
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Using AISI 1020 steel which has a yield strength of about 206 MPa, and using a design factor of 1.5,
max = 206 MPa 10^6 Pa/MPa(2 1.5)max = 68,666,666 Pa
From Shigley's Mechanical Engineering Design, 8th Edition, page 212
max = Sy / 2n
Where max = maximum shear stress, PaSy = yield stress, Pan = design factor
163.1415 68,666,666
1.5 MtD =
1000
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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 Plunger Bore and Stroke
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b. Calculation to Determine Eccentric Sheave Diameter
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 facilitate easywelding of the eccentric sheave to the shaft
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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 Shaft Size
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c. Calculation to Determine Strength of Eccentric Sheave Weldment
Stresses in welded joints in torsion" = Mr / J
Where = shear or torsional stress, PaM = torsional moment, Nmr = distance from the centroid of the weld group to the point in the weld
of interest, mJ = second polar moment of area, m4
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For circular fillet welds
Ju = 2 pi 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) pi (22mm/1000mm/m)2/4
Fp = 13,304 N
Maximum moment = Fp (stroke/2). For 23mm stroke, M = 13,304 N (23mm/1000mm/m) 2M = 153 Nm
J = 0.707hJu
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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.)(23.1415)((27mm/1000mm/m)2)3" =
" = 39,682,448 N/m2 or 39.7 MPa (5.473 ksi)
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c. Calculation to Determine Crankshaft Bearing
Bearing Catalog Load Rating
C10 =1/a
FDLDnD60LRnR60
Where C10 = catalog load rating, kNFD = 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
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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) pi (bore in mm/1000mm/m)2/4
= Fbmax
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Plunger Bore, mm
18 19 20 21 22FP, kN 8.91 9.92 11.0 12.12 13.30Fbmax 11.13 12.40 13.74 15.15 16.63
Table 3: Maximum Bearing Load at Different Plunger Bore Sizes
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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 98.12 104.71 111.40C10, (kN)
(roller bearing) 69.55 75.03 80.61 86.31 92.11Computed Shaft
Dia, (mm) 23.1 24.0 24.8 25.6 26.4Std. Shaft Dia., (mm) 25 25 25 30 30AvailableBearing - - - - -
Table 4: Shaft Bearing Load Rating
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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 98.12 104.71 111.40C10, (kN)
(roller bearing) 69.55 75.03 80.61 86.31 92.11Computed Shaft
Dia, (mm) 23.1 24.0 24.8 25.6 26.4Initial Std. Shaft
Dia., (mm) 25 25 25 30 30Adjusted Std.
Shaft Dia., (mm) 30 30 30 30 30Available
Bearing, SKFNU 2306NJ 2306
NU 2306NJ 2306
NU 2306NJ 2306 - -
Table 4: Shaft Bearing Load Rating
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Available SKF Bearing for the crankshaft
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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 78.50C10, (kN)
(roller bearing) 55.64 60.02 64.49Eccentric Sheave
Internal Dia., (mm) 30 30 30Eccentric 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
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e. Pump Driver Selection
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e. Pump Driver Selection
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e. Pump Driver Selection
Manufacturer Hp Speed, rpm Efficiency,% 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 2,480 1LE29313AC116AA3
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
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e. Pump Driver Selection
Manufacturer Hp Speed, rpm Efficiency,% 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 2,480 1LE29313AC116AA3
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
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Plunger Bore,mm
Plunger Stroke, mm Speed, rpm Remarks
1821 1,497
Disregarded. Motor speed is only1,200 rpm.22 1,429
23 1,367
1921 1,344
Disregarded. Motor speed is only1,200 rpm.22 1,283
23 1,227
2021 1,213 Disregarded. Motor speed is only 1,200 rpm22 1,158 Selected Plunger Bore & Stroke23 1,107 Disregarded. Not optimal.
2121
Disregarded. No crankshaft bearing available.2223
2221
Disregarded. No crankshaft bearing available.2223
Selected Plunger Bore and Stroke
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Since the standard shaft diameter chosen is 30mm, and the eccentric sheave diameter is 60mm, the minimum sheave thickness, sw, is recalculated.
Sd2 = (s/2) + (D/2) + sw
From
sw =Sd - s - D
2
sw =60 - 22 - 30
2= 4 mm
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f. Calculation to determine wrist pin sizeAISI 1030 steel is chosen because of higher yield strength than AISI 1020 steel.
Based on maximum shear stress theory, the maximum allowable shear stress,
max = Sy / 2n
Where the yield strength, Sy, for 1030 steel is equal to 260 Mpa. Using a design factor of 1.5,
max = 260 / (21.5) = 86.7 Mpa
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f. Calculation to determine wrist pin size (contd)Wrist pin will fail by shearing on sections a and b.
max = 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.
max = Fp / 2A = Fp 2(pidw2/4) ; dw = wrist pin diameterBy transposing the equation above
dw = (4Fp/2pi max)1/2
411kN1000N/kN23.141586.7Mpa106Pa/Mpadw =
dw = 0.00899m or 8.99mm
The next preferred size is chosen which is 10 mm.
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g. Computation to determine the wrist pin bearing
The bearing size is selected based on the static load rating, C0, because the wrist pin
Basic static load rating C0
a. makes a slow oscillating or alignment movements under loadb. rotates under load at very low speed
C0 = S0 P0Where C0 = basic static load rating, kN
P0 = equivalent static bearing load, kNS0 = static safety factor
Based on SKF guideline, for non-rotating roller bearing with normal operations, S0=1. Since P0=11kN, then
C0 = 111kNC0 = 11kN
From SKF catalogue, a drawn cup needle roller bearing with C0=11.4kN is available. The bearing designation is HN1010.
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h. Bill of Materials
Item Description Specifications Quantity1 Crankshaft 30 mm O.D., AISI 1020 steel 12 Crankshaft Suppport Bearing SKF NU 2306 or NJ 2306 23 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
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j. Triplex Pump Solidworks Digital Prototype
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j. Triplex Pump Solidworks Digital Prototype
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j. Triplex Pump Solidworks Digital Prototype
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j. Triplex Pump Solidworks Digital Prototype
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i. Triplex Pump Solidworks Digital Prototype
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j. Triplex Pump Solidworks Digital Prototype