project-fum-final-fume-extractor-for-cnc-machine.pdf

Studocu is not sponsored or endorsed by any college or university
Project fum Final] - fume extractor for cnc machine
Mechanical Internship project (Addis Ababa Science and Technology University )
Studocu is not sponsored or endorsed by any college or university
Project fum Final] - fume extractor for cnc machine
Mechanical Internship project (Addis Ababa Science and Technology University )
Downloaded by Rakshith M S Gowda (rakshithms4545@gmail.com)
lOMoARcPSD|20608229

ADDISABEBA SCINCE AND TECHNOLOGY UNIVERSTY 2021
Declaration
We hereby declare that this internship project is an authentic record of our own works
as requirements of Industrial Training during the period from July 2021 to September
2021 for the award of degree of B.Sc. in Mechanical Engineering, AddisAbaba
Science and Technology University, Addis Ababa, under the guidance of Mr.Weyuma
Tolera.
1 | P a g e
BELAYNEH KINDE METAL ENGINEERING
`
lOMoARcPSD|20608229

Abstract
CNC machine produce fumes which are known to be dangerous to human health. In
order for the operators to work in a safe environment, a means of removing these
fumes from the working environment must be provided during the welding and
cutting process. This is the purpose for which this paper has been developed. Fume
extractors are generally known to be fixed to the walls of factories and places where
fumes need to be extracted from. Materials for design and fabrication of the fume
extractor was selected based on cost, safety, functionality, ease of availability and
affordable maintainability. The fabricated fume extractor was tested on several
welding and cutting sites and found to be very effective in extracting fumes from the
operators breathing zone. It was also observed that the function of the extractor did
not adversely affect the welding and cutting process.
2 | P a g e
`
lOMoARcPSD|20608229

ACKNOWLEDGEMENT
3 | P a g e
`
lOMoARcPSD|20608229

LIST OF FIGURE
Figure 1.1.Scroll or Volute...........................................................................................10
Figure 1.2.wheel vector diagram..................................................................................10
Figure 1.3.Tip speed/static pressure relationship.........................................................11
Figure 1.4.Velocity triangle at inlet and outlet blade...................................................12
Figure 1.5.Block representation of energy conversion for motor................................13
Figure 1.6.Electric Motor.............................................................................................14
Figure 1.7.HEPA air filter............................................................................................15
Figure 1.8.Air filter box...............................................................................................15
Figure 1.9.Pipe.............................................................................................................16
Figure 1.10.Bolt and Nut..............................................................................................16
Figure 1.11.Washer.......................................................................................................17
Figure 1.12.Weldment Frame.......................................................................................17
Figure 1.13.CNC cutting machine...............................................................................18
Figure 3.1.Conceptual Design......................................................................................26
Figure 4.1.Radial type centrifugal impeller.................................................................28
Figure 4.2.Base simple beam-Concentrated load at center..........................................36
Figure 4.3.Free body diagram......................................................................................36
Figure 4.4.Shear force and bending diagram of base...................................................37
Figure 4.5.Base indication............................................................................................38
LIST OF TABLE
Table 1.Table of Material Selection.............................................................................21
Table 6.1.Results of the design.....................................................................................41
4 | P a g e
`
lOMoARcPSD|20608229

Nomenclature
A – Area
V – Volume
Pa – Pascal
v – Velocity
D – Diameter
l – Length
w – Width
h – Height
F – Force
Q – Discharging flow
T – Torque
P – Power
τ – Shear stress
5 | P a g e
`
lOMoARcPSD|20608229

LIST OF ACRONYM
AC--------ALTERNATE CURRENT
HEPA---- HIGH EFFICIENCY PARTICULATE AIR [FILTER
OHS-------OCCUPATIONAL HEALTH AND SAFETY
COSHH--- CONTROL OF SUBSTANCES HAZARDOUS TO HEALTH
ASHRAE---SOCIETY OF HEATING REFRIGRATING AND AIR-CONDITONING
ENGINEERING
6 | P a g e
`
lOMoARcPSD|20608229

ASME ----- AMERICAN SOCIETY OF MECHANICAL ENGINEERS
7 | P a g e
`
lOMoARcPSD|20608229

8 | P a g e
`
lOMoARcPSD|20608229

CHAPTER ONE
INTRODUCTION
1.1Background Justification
Fume extractors are widely used in many industrial processes to capture fumes
evolved from reaction vessels. Fume from many processes is often toxic and
corrosive. Release of such fumes poses both an environmental problem and a health
and safety hazard for the workers. The fume extractors are designed for direct source
capture removal of smoke, dust, fumes and other airborne contaminants from a wide
variety of industrial and other applications. Our design specifically to capture fume
from plasma cutting machine. A multi-stage filtration and filter options will provide
the ideal system to improve the air quality by effectively trap airborne contaminants
before they enter the operator’s breathing zone. The machine is made up of several
separate components put together to form a linked mechanism. It has;
1.1.1Centrifugal Blower
A centrifugal blower is a pump or motor that moves air. It pulls the air inside the
blower and then pushes it out at a 90º angle. The two main components of a
centrifugal blower are the motor and the impeller.
Centrifugal blower consists of an impeller with small blades on the circumference,
shroud to direct and control the airflow into the center of the impeller and out at the
periphery. The blades move the air by centrifugal force and throwing it out thus
creating suction inside the impeller and suction duct. The pressure rise and flow rate
in centrifugal blowers depend on the peripheral speed of impeller and blade angles.
The blower can therefore be described as a device, which converts driver energy to
ʼ
kinetic energy in air by accelerating it to the outer rim of a revolving device known as
an impeller. The impeller is always placed directly onto the shaft of the suction motor.
Air enters the impeller axially through the inlet nozzle which provides slight
acceleration to the air before its entry to the impeller. The action of the impeller
swings the air from a smaller to a larger radius and delivers the air at a high pressure
and velocity to the casing. The centrifugal energy also contributes to the stage
pressure rise. The flow from the impeller blades is collected by spirally-shaped casing
known as scroll or volute. It delivers the air to the exit of the blower. The scroll
9 | P a g e
`
lOMoARcPSD|20608229

casing can further increase the static pressure of air. The outlet passage after the scroll
can also take the form of a conical diffuser.
Figure 1.1.Scroll or Volute
Centrifugal blowers are fundamentally high speed machines (compared with the
reciprocating rotary or displacement type). The recent advances in stream turbine,
electric motor, and high speed gearing design have greatly increased their use and
application. Centrifugal blowers are used in many applications such as for high
pressure air, chemical plants, blast furnace, sewage aeration blowers, biogas
application, air plane supercharger, farm machinery and other many engineering
fields.
Centrifugal blower may be classified into three basic types according to blade
configuration
1. Forward curve blade
2. Backward inclined blade
3. Radial or straight blade
Each type has its own application range and limits. Modifications of these basic types
include radial tip, mixed flow and tangential flow.
Figure 1.2.wheel vector diagram
10 | P a g e
`
lOMoARcPSD|20608229

The tip speed required to produce the required air particle velocity varies substantially
with the type of blade used. Fig 1a, 1b and 1c shows vector diagrams of forces in
forward curve, backward curve and radial blade impellers, respectively. Vector V1
represents the rotational or tangential velocity, and V2 represents the radial velocity of
the air flow between the blades with respect to the various blade shapes. Vector R
represents the resultant velocity for each of these blade shapes. Note that R for the
forward curve impeller is the largest with the backward inclined impeller the smallest,
while the radial blade lies somewhere in between. In fid 2, which shows a typical tip
speed/static pressure relationship for various types of centrifugal blow
Figure 1.3.Tip speed/static pressure relationship
After careful considerations of the various types of blower available, the radial bladed
blower was selected as the one suitable for our project design. This blower is
characterized by high pressure, medium flow and continuous power increase and very
suitable for handling dust-laden, moist air/gases. This blower is equally known to be
well suited for high temperature and handle heavily contaminated airstream.
11 | P a g e
`
lOMoARcPSD|20608229

Radial Blade Blower
Steel plate and paddle wheel are two of the common names for radial blade blower.
The impeller blades are generally narrower, deeper and heavier than forward curve
and backward inclined blades. A radial blade impeller usually comprises six to fifteen
equally spaced flat blades extending
Radially from the center of the hub. Radial blades will be radial at its outlet, but at the
inlet of such blades there will be curvature and this curvature will be in the direction
of rotation of impeller. Outlet angle to the impeller blade i.e. β2 will be equal to the
90deg.
Velocity triangle
Absolute velocity of air at inlet to impeller blade will be axial and it means that there
will not be any tangential component of absolute velocity of air at inlet i.e. velocity of
whirl at inlet (Vω1) will be zero.
Vω2 = u2, if β2 =90deg, Radial blades
Figure 1.4.Velocity triangle at inlet and outlet blade
Electric motor is the other part of centrifugal blower in which impeller is mounted.
Electromechanical energy conversion involves the interchange of energy between an
electrical system and mechanical system through the medium of a coupling magnetic
field. When the conversion takes place from electrical to mechanical form, the device
is called a motor. The primary quantities involved in the electrical system are voltage
and current while the analogous quantities in the mechanical system are torque and
speed respectively.
12 | P a g e
`
lOMoARcPSD|20608229

Figure 1.5.Block representation of energy conversion for motor
An AC induction motor primarily consists of a stationary member, called the stator,
and a rotating member, called the rotor. The stator is made of steel with slots cut out
along the inner perimeter to carry coil windings. Coils of insulated copper wire filling
the stator slots are wound around the stator teeth, the steel regions between adjacent
slots. The rotor fits snugly in to the stator forming a concentric structure with a small
radial gab between them. Rotors slot are filled with conductors composed of coils of
copper wire or bars of copper or aluminum. There are two common types of AC
induction motor namely; Squirrel cage and slip ring motor.
Slip ring motor
The motor which employing the wound rotor is known as a slip ring induction motor
or phase wound motor. It consists laminated cylindrical core which has a semi –
closed slot at the outer periphery and carries three- phase insulated winding. The rotor
is wound for the same number of poles as that of the stator.
Squirrel cage motor
The motor which employing squirrel cage type rotor is known as the squirrel cage
motor. The construction of the rotor is rugged and simple. The rotor of the motor
consists the cylindrical laminated core having semi-closed circular slots and short
circuit at each end by copper or aluminum ring called short circuiting ring. It is not
possible to add any external resistance in the rotor of the circuit.
13 | P a g e
`
lOMoARcPSD|20608229

One of the major differences between the slip ring and the squirrel cage motor is that
the slip ring motor has an external resistance circuit for controlling the speed of the
motor. Whereas in squirrel cage motor, it is not possible to add any external circuit
because the bar of the motor is permanently slotted at the end of the ring.
Induction motors — or (in the context of blowers in particular) often called by the
more playful squirrel-cage motors (to avoid confusion with inducer-blower products).
In fact, these motors are the most common used in blowers today, as they excel in
high-horsepower blower and cooling-fan applications
Figure 1.6.Electric Motor
1.1.2 Air filter
During the production process, there is a high possibility that dangerous fumes, smoke
and dust will form in the work environment. These can prove a hazard to not just the
operators working on the site. So, finding the best possible filtration system to trap the
fume and dust particles in a safe manner is something that should be high on our
priority list. Filter performance is significantly reduced with their use and depending
on the filter type and operating conditions (i.e. air quality and number of contaminants
that are encountered) they have to be periodically replaced or cleaned. Filter selection
is based upon the function and the role of the filter under different operating
conditions. They are differentiated based on their effectiveness to remove certain
categories of air particulates. The most common parameters that are used to
differentiate and rate different filters include; Efficiency, Air flow resistance and Dust
holding capacity
The most common materials used to make fume extraction system filters are:
 Cellulose
 Cellulose-Polyester Blends
 Spun-Bond Polyester
14 | P a g e
`
lOMoARcPSD|20608229

 PTFE Coated Blends
Your more affordable filters are made from cellulose, but you get into some
cellulose-polyester blends. For improved surface loading, the cellulose-polyester
blends will get a PTFE coating.
When you're looking for superior filtration, go to the HEPA filters. Because a HEPA
rated filter according to ASME, or the US Department of Energy, is 99.97% efficient
at capturing 0.3 microns, it captures the most difficult microns to extract.
1.1.3 Air filter box
Air filter box used to hold two air filter. And filtration
process is processed on it.
It has two holes for intake & exhaust of fume.
Intake and exhaust pipe are fitted on it.
Figure 1.8.Air filter box
1.1.4 Pipe
When designing a fume extraction system, you must also consider the type of piping
material. For safety reasons and as required by the OHS regulations, it is
recommended to use steel pipes, preferably with a smooth inner wall, to minimize
resistance, ensure unhindered airflow, and maintain the optimum speed. In practice,
15 | P a g e
`
Figure 1.7.HEPA air filter
lOMoARcPSD|20608229

traditional spiral ducts, smooth pipes and plastic sewage pipes are used for extracting
fume. Although all of these types have their pros and cons, the use of plastic piping is
certainly cheaper but certainly dangerous. The use of such pipes involves the risk of
explosion, which puts employees of the plant and your machinery at risk. Therefore,
you have to analyses whether it will generally pay off to save on the piping.
Explosion safety is not the only aspect to be taken into account when selecting piping,
as minimizing air resistance is another equally important aspect. It is recommended to
use pipes with a smooth interior and duct fittings with soft curves and large radii to
prevent blockages inside the dust extraction system. The best solution is a steel pipe
with seam welds, or even better butt welds.
Figure 1.9.Pipe
1.1.4 Bolt and nut
Bolt and nut used in this project to join different component of this machine. We use
different dimension of bolt and nut based on the component size and strength of
material.
The material we have used is stainless steel.
Figure 1.10.Bolt and Nut
1.1.5 Washers
Washer is a flat thin ring or a perforated plate used in joints or assemblies to ensure
tightness and relieve friction.
16 | P a g e
`
lOMoARcPSD|20608229

Figure 1.11.Washer
1.1.6 weldment frame
It is used to support all component of the machine.the material we have used in our
design is sainless steel because it have better strength and easily availability of the
material in the shope.
Figure1. 12.Weldment Frame
1.2 Problem statement
When we stayed in BKME to do our internship program for the time of three months,
we have seen some problem which is not suitable for the work. From those problems
we select one which is look like as follow;
Plasma CNC machine are highly risky machine among from other machines available
in the material preparation shop. An employee who works on these machines are very
susceptible to high risk. Especially operators of plasma CNC machine are capable of
being affected by a poisonous fume which comes out of the CNC machine while
cutting, that cause an allergy on the respiratory system and also cause cancer and
bareness ,the environment is affected by this fume and The productivity of the
company decreases due to the workers are not happy.
And also there are also another problem the product quality decrease due to the fume.
Then after identifying the problem we were able to design a fume extractor which it
absorbs a fume from the surrounding.
17 | P a g e
`
lOMoARcPSD|20608229

Figure1. 13.CNC cutting machine
1.3Objective
1.3.1General objective
The main objective of this project is to design Fume extraction machine for CNC
cutting machine.
1.3.2Specific objective
 To design centrifugal blower
 To design fume extraction pipe
 To design air filter
 To design air filter box
 Modeling using solid work software for part and assembling drawings.
1.4. Scope of the project
18 | P a g e
`
lOMoARcPSD|20608229

This project encompasses different features such as the methodology, working
principles, part design and specifications parameters, solid work and finally we have a
plan to do the prototype as much as possible. In the cause of carrying out this project,
the following design considerations were given a due attention; the machine should be
efficient during use in the shop as well as safety and ease of operation. In addition, the
cost of construction was also considered.
1.5 .Significant of the project
A significant percentage of individuals around the world spend a bigger portion of
their 24 hours at their workplace. It’s for this reason that it is important for employers
to ensure that their employees’ workplace is conducive and comfortable to work. A
healthy working environment is essential to the health of the workers and improves
the efficiency of all the staff in the workplace. One way of improving the workplace
to suit the employees’ needs is by fume extraction. Having correct extraction systems
installed is not only important to meet workplace regulations, but also to ensure the
safety and health of your operators. Reduce contamination of surfaces as well as the
machines you service, produce or work on.
1.6.Methodology
In this design the following methods are being used
 Getting information by referring previous existing document manuals and
reports which are connected to this project.
 Making basic assumption and taking in account design consideration.
 Selecting the appropriate material for the design
 Design the required part of the fume extract machine
 Making the detail drawing and assembly drawing using solid work software
1.4.1 Materials used for construction
19 | P a g e
`
lOMoARcPSD|20608229

Selection of suitable material must to be considered in account. The suitable of
material with the process of fabrication as well as the compatibility of the material
with the environment. The selection of proper material for engineering the best
material is one with which save design objective let the maximum cost.
Different manufacturing factor have been consider selecting material is the first target
for designing or manufacturing one machine. The process responsible for their
commanding material that will be suitable for process consideration.
Selecting material must consider the requirement or the material properties, sufficient
strength and easily workable. The most economical material that satisfies both
processes and mechanical requirements should be considered the material will give
that: -
 Safety during working
 Machinability
 Productivity
 Low cost over the working life
The material properties are very important in the selection of the material. Some
important mechanical properties which are considered in material selection are:-
 Strength
 Roughness i.e., fracture resistance
 Hardness i.e., wear resistance
 Corrosion resistance
But the following factors should be considered, which the material is:-
• Availability of the material
• Suitability of material for the working consideration service
• The cost of the material and easily fabrication
In our design the material we have used base on the above criteria listed in the below
table;
20 | P a g e
`
lOMoARcPSD|20608229

No Machine
component
Reason for selection Material selected
1 Centrifugal
blower
High Static pressure
and suitability for
high temperature
Radial bladed centrifugal
blower
2 Electric motor Ability to overcome
shear stress,
durability, regulates
speed and torque
9.9 hp electric motor
3 Air filter for better it works and the
longer the replacement
interval.
Cellulose-Polyester
Blends
4 Air filter box High fatigue and impact
strength
Stainless steel
5 Bolt ,Washer and
nut
High fatigue and impact
strength
Stainless steel
6 Pipe effective and easy passage
of the fume
Stainless steel
7 Weldement frame High fatigue and impact
strength
Milde steel
8 paint Corrosion resistant and
good texture
Corrosion resistant
paint
Table 1.Table of Material Selection
CHAPTER TWO
LITERATURE REVIEW
21 | P a g e
`
lOMoARcPSD|20608229

2.1Introduction
Fume extractors has been developed and built throughout since welding related fumes
are known to cause harm on human health. Different projects have been done and
implemented to construct and design different kinds of extractors.
2.2 LITERATURE SURVEY
Fume extraction torch development began in the 1970s. Research undertaken from
1985 to 1990 using a tracer gas concluded that a flow rate of the order of 100
m3
h−1
would efficiently capture fumes (Cornu et al., 1991). Torch inclination was
found to have a strong influence on capture performance during these studies.
Experiments conducted by Yapp et al. (2001) represented the first overall approaches
(ergonomics and capture efficiency) to address this problem. The Econweld project
(Marconi and Bravaccini, 2010), which was co-financed by the European Union,
included a facet with similar aims to those of Yapp, i.e. to design a lightweight,
efficient, ergonomic torch, which would curtail exposure to welding fumes and
cutting machine.
In the UK, the health and safety executive has implemented COSHH regulations to
ensure all industrial workplaces protect the health of their employees via effective
local host exhaust ventilation. This policy is now being mirrored in other parts of the
world including China and the north America.
CHAPTER THREE
METHODOLOGY OF THE RESEARCH
3.1 Planning method
22 | P a g e
`
lOMoARcPSD|20608229

The proposed product planning process for our fume extraction project considers the
collection of sequence of product development tasks to be executed. By considering
project opportunities, our product planning involves the below discussed set of
activities approved by the planning process and sequenced in time:
 Identify opportunities: collects possibilities for new product platforms,
enhancements, and fundamentally new products from several sources
within and outside the firm.
 Evaluate and prioritize projects: to select the most promising projects to
pursue in evaluating and prioritizing opportunities for the product/s to be
designed or developed.
 Allocate resources and plan timing: Are the total resources allocated to
product development sufficient to pursue the firm’s competitive strategy?
 Complete pre-project planning: Pre-project planning takes place after the
project is approved and before substantial resources are applied.
 Reflect on the results and the process: In this final step of the planning and
strategy process, the team should ask several questions to assess the
quality of both the process and the results. Such as
 Is the opportunity funnel collecting an exciting and diverse set of product
opportunities?
 Does the product plan support the competitive strategy of the firm?
 Does the product plan address the most important current opportunities
facing the firm?
 Does the core team accept the challenges of the resulting mission
statement?
 Are the elements of the mission statement consistent?
 Are the assumptions listed in the mission statement really necessary or is
the project over constrained? Will the development team have the freedom
to develop the best possible product?
3.2. Data collection method
All needed data's which required for analytical and modification will be collected
from different source. This includes collecting data from:
 Primary date collection method which is by visual inspection and
Observing how the fume is extracted from the plasma machine.
23 | P a g e
`
lOMoARcPSD|20608229

 Secondary source data collection method such as websites and different
books related to fume extraction
3.3. Analysis method
Analysis method is part identifying problems, designing the device, specify the
process, selecting the proper materials that are suitable for the device and using
software simulation to view the dimension of the machine.
Selection of suitable material must to be considered in account. The suitable of
material with the process of fabrication as well as the compatibility of the material
with the environment and its cost as well. Selecting material is the first target for
designing or manufacturing one machine. The process is responsible for making the
material suitable for process consideration.
Selecting material must consider the requirement or the material properties, sufficient
strength and easily workable. The most economical material that satisfy both
processes and mechanical requirements should be considered. The material properties
are very important in the selection of the material. Some important mechanical
properties which are considered in material selection are: -
 Strength
 Corrosion resistance
 Roughness which is fracture resistance
 Availability of the material
 The cost of the material and easily fabrication.
3.4. Idea generation methods
We generate this idea when we saw the plasma machine produce fume that is
dangerous for the workers, the company and environment. Since this fume can cause
different disease.
3.5.Evaluation Method
The evaluation of our internship project depend on the efficiency, cost, design
condition and time of service. Due to the nature of working centrifugal blower is best
for the efficiency around 50-60%.we can buy accessories to machine and easily
service.
24 | P a g e
`
lOMoARcPSD|20608229

3.6. Collection of data
We have used both the primary and secondary data collection method to get enough
knowledge about the engine cylinder liner extractor. The primary data collection
method we have used to collect the data are;
• by observation Evaluation Method
• by interviewing the CNC machine operator
• by taking measurements
We also used the secondary data collection method by;
• reading different references related to our project,
• searching different websites
• From different journals related to fume extractor machine.
•
3.7. Research & Analysis
We observed that in the company’s fabrication shop environmental pollution problem
caused by that is released from the CNC machine, so our design is extraction of fume
from the CNC machine. The design solves disease related to poisons gas like co2 that
are leave in the form of fume. .
Based on our observation often the worker loses their motivation for full capacity of
work.
3.7 Function and task analysis
Selecting the the right idea and design for solving the the problem is the main
function and task of our our analysis of the information determined
25 | P a g e
`
lOMoARcPSD|20608229

Figure 3.1.Conceptual Design
26 | P a g e
`
detaileofthe
design
designof
motor
designof
volute
desidnofair
filter
designofbox
air filterof
designof
bolt,nutand
washer
Assembling design
lOMoARcPSD|20608229

CHAPTER FOUR
DESIGN PROCESS
.1 Recognition of need
Our machine is used for
 removing fumes from work place
 creating comfortable of work place
 providing healthy working environment
4.2. Definition of problem
Plasma CNC machine are highly risky machine among from other machines available
in the material preparation shop do to the production fume from the machine..
Employees who work on these machines are very susceptible to high healthy risk and
the environment is affected by this fume.
4.3. Analysis
Our project is very essential, easy to operate and to install on CNC machine.
We think that the company and all the worker of the shop keep their susceptibility by
creating the work environment free from fume.
4.5 .Design of calculation
4.5.1. Design centrifugal blower
The main components of a centrifugal blower are the motor ,the impeller, volute
casing. We design each component precisely by considering the important case
1.1Design of impeller
Design specifications
Flow discharge Q = 48m3
/min = 0.8m3
/sec
Air density =1.16Kg/m3
Outlet blade angle β2 = 900
Atmospheric pressure = 1.013*105
Pa
Atmospheric temperature = 300
c=303K
Manometric head = 12m
27 | P a g e
`
lOMoARcPSD|20608229

Blade diameter;
From the optimum performance specification, it is stated that the ratio of the internal
diameter to the external diameter is to fall between 0.4 to 0.7 as stated in
the ASME code.
That is 0.4 < D1/D2 < 0.7, for this design
The ratio D1/D2 = 0.44 is taken.
We take the inlet diameter D1 = 70mm, then D2 = D1/0.45 = 150mm
Number of blades;
From ASME code, for optimum performance the number of blades is given by
C = (8.5 sin β2) / (1-D1/D2)
From this design β2 = 900
and D1/D2 = 0.466
= 8.5 sin β2 /1-0.44
= 15 blades
Figure 4.1.Radial type centrifugal impeller
Blade width
It is given from ASME code specification that, the blade width is given by the
formula.
W = 6 (D1/2)/C+1, where C is the number of blades.
W = 6 (70/2) / 15+1 = 15mm.
Number of revolutions per minute
For centrifugal blower to deliver an air, the centrifugal head must be equal to the total
head.
Thus, U2
2
– U1
2
/ 2g = H
28 | P a g e
`
lOMoARcPSD|20608229

Where U1 and U2 are the respective impeller velocities at inlet and outlet.
U1 = π D1 N / 60 and
U2 = π D2 N / 60
So,
U2
2
– U1
2
= 2gH
= [ π D2 N / 60 ]2
– [ π D1 N / 60 ]2
= 2*9.81*12
= [ π*0.16 N / 60 ]2
– [ π*0.070 N / 60]2
= 294.3
= (0.008377N)2
– (0.003665N)2
= 294.3
= 0.00004 N2
– 0.0000083 N2
= 235.44
= 0.0000567 N2
= 235.44
N = 2037.7 rpm.
Analysis of the various velocities of the blades
From the velocity diagram above, we can determine different velocities;
 Absolute velocity of the air at outlet (v2)
 Relative velocity of the air at outlet (vr2)
 Relative velocity of the air at inlet (vr1)
 Whirl velocity at out let (vw2)
 Velocity of the blade at the inlet (u1)
 Velocity of the blade at the outlet (u2)
 Velocity of flow at out let (vf2)
The inlet and outlet blade velocity are calculated as;
U1 = π D1 N / 60 = (π*0.07*2037.7) / 60 = 7.46 m/s
U2 = π D2 N / 60 = (π*0.150*2037.7) / 60 = 16m/s
Now, to calculate other parameters we can prefer to use the continuity equation first.
Q = π D2 q Vf2 = π D1 q Vf1 = 0.8 m3
/s where; q = 0.022
We can now, calculate the flow velocity at inlet and outlet using the equation above;
Vf2 = Q / π D2 q = 0.8 / (π*0.15*0.022) = 77 m/s
Vf1 = Q / π D1 q = 0.8/ (π*0.07*0.022) = 165m/s
From the outlet velocity triangle, we can obtain the α2 as follows;
tan α2 = Vf2 / Vw2 = 72 / 16 = 3.789
α2 = 78o
From the inlet velocity triangle, we can obtain the β1 as follows;
29 | P a g e
`
lOMoARcPSD|20608229

tan β1 = Vf1/ U1 = 165/ 7.46 = 22.09
β1 = 87.4o
By considering the outlet velocity triangle we can get the absolute velocity of the air
V2.
Sin α2 = Vf2 / V2, then by rearranging;
V2 = Vr2 / sin α2 = 77 / sin 78 = 78.7 m/s
V1 = Vf1 = 165 m/s – assuming radial flow at inlet
Again, for radial bladed blower i.e. 90o
, U2 =Vw2 =16m/s
The relative velocities Vr1 and Vr2 at inlet and outlet are given from velocity triangle.
Vr2 = Vf2 / sin β2 = 77 / sin 90o
= 77 m/s
Vr1 = Vf1 / sin β1 = 165 / sin 87.4o
= 165.2 m/s
Efficiency of the blower
E = manometric head / head imparted by impeller
Head imparted by the impeller = Vw2 U2 / g
= 16 * 16 / 9.81
= 25m
E = 12/ 25 = 48%
Working temperature
Temperature equivalent to work done;
T02 – T01 = σU2
2
/ cp; σ = Vw2 / U2 = 1
T02 = T01 + σU2
2
/ cp
T02 = 303 + 162
/ 1005
T02 = 303.25K
Static temperature at impeller exit;
T2 = T02 – V2
2
/2cp
T2 = 303.25– 772
/ 2*1005
T2 = 300.3K
Overall pressure ratio
P03 / P02 = [1+ (E σU2
/ cp T01)]3.5
= [1+ (0.5* 162
/ 1005*303)]3.5
= 1.002
30 | P a g e
`
lOMoARcPSD|20608229

1.3Design of Electric motor
Material selected: Squirrel cage AC electric induction motor
Reason for selection: Relatively cheap, robust, efficient and reliable..
The standard voltage input for this design will be 220/380V
Horse power required by the motor;
This given by the formula;
P = Q γ H / 550; where γ = ρ g
= 1.16 * 9.8
= 11.368
Where; Q--- Discharge flow and
H ---Manometric head
P = (48*11.368 * 12) / 550
= 12Hp or
=12*746
=8.952KW
Torque developed
T = P * 60 / (2πN )
= (8.952KW* 60) / (2π *2400 )
= 35.6364Nm/s
2. Design of the filter
Material selected: Cellulose-Polyester Blends
Reason for selection: its ability to trap large amount of fume and you get better
surface loading and improved clean ability and they capture particles very well.
Design calculation;
A = l * w
where; l = length and
w=width
For our design; We select Industrial HEPA air filter have;
l = 50cm and
h = 60 cm
Thickness= 3inch (76.2mm)……standard
A = 0.5 * 0.6= 0.3 m2
31 | P a g e
`
lOMoARcPSD|20608229

3. DESIGN OF AIR FILTER BOX
Filter box are used to hold air filter.
Material selected; stain less steel
Reason for selection; High fatigue and impact strength
Dimension
For our design we select;
L=500mm
Width=500mm
Height=600mm
Volume=L*W*H where; L=length
W=Width
H= Height
=500*500*600
=150*106
mm3
=150cm3
4. DESIGN OF BOLT AND WASHER
In order to fit the motor to its support plate we have used four bolt and
To join blower to filter box we use four bolt.
For our design we select M15mm bolt
Material selected: Stainless steel
Tensile yield strength(Syt) 505MPa
Permissible shear stress Ssyt=0.5Syt
Factor of safety (fos)= 3
Reason for selection: Readily available
Criteria for selection: High fatigue and impact strength
When a force applied on the bolt, a shear stress might be happened. So, we can design
a bolt using
a maximum force(F) 1.64KN ,
tensile yield strength(Syt) 505MPa
Permissible shear stress(τ) =
=0.5*505Mpa/2
32 | P a g e
`
lOMoARcPSD|20608229

=126.25Mpa
Now check our selection safe or not
First calculate induced stress on the material
Where; n= is numbers of bolt
F= is load applied on it
A=shear area of bolt
=
=84.16Mpa
So that the allowable stress is greater than the induced stress therefore
the design is safe.
Dimension of nut for M15 bolt
The height of the nut h can be determined by Equating the strength
of the bolt in tension with the strength in shear.
The procedure is based on the Following assumptions:
(i) Each turn of the thread in contact with the-
Nut supports an equal amount of load.
(ii) There is no stress concentration in the threads.
(iii) The yield strength in shear is equal to half of the yield
strength in tension (Ssy = 0.5Syt).
(iv)Failure occurs in the threads of the bolt and not in the
threads of the nut.
The threads of the bolt in contact with the nut are sheared at the
core diameter dc
dc=0.8d
dc=12mm
The height of the standard nut,
h = 0.8dh=12mm
33 | P a g e
`
lOMoARcPSD|20608229

Analysis of washer design
As we consider a suitable material for washer as a commercial steels
We know that the nominal diameters of bolt is
Then the diameters of washer can be calculated as
= 1.2*d = 1.2*15= 18mm
The thickness of washer is given by
= 0.15*d = 2.25mm
The inner diameters of washer is given by
= d+1 = 16mm
Bolt for joining of pipe to blower and air filter box
The material is the same as above
We select M10 bolt
Number of bolt is 8
The force required to tighten is1KN
Now check our selection safe or not
First calculate induced stress on the material
=
=12.73Mpa
the design is safe.
Dimension of nut for M10 BOLT
The threads of the bolt in contact with the nut are sheared at the
core diameter dc
d c= 0.8d
dc = 8mm
The height of the standard nut,
h = 0.8dh
34 | P a g e
`
lOMoARcPSD|20608229

=8mm
 Analysis of washer design for M10 BOLT
As we consider a suitable material for washer as a stainless steel
We know that the nominal diameters of bolt is
Then the diameters of washer can be calculated as
= 1.2*d = 1.2*10 = 12mm
The thickness of washer is given by
= 0.15*d = 1.5mm
The inner diameters of washer is given by
= +1 = 11mm
5. Design of pipe
Material selected: Stain less steel have a thickness of 2mm
Reason for selection: effective and easy passage of the fume
Criteria for selection: easily available in the market or to fabricate it in the shop.
Constant velocity method is used for sizing this duct which convey as recommended
by ASHRAE. From American conference of governmental industrial hygienists
(ACGIH), it recommended 10 to 13 m/s minimum transport velocity for the fume. For
this work we have selected 10 m/s of velocity.
For duct, using continuity equation
Q = A * V
A = Q / V
Where; Q = fume flow rate
=0.8 m3
/s
V = fume velocity
=10 m/s
A = area of the duct
A = 0.8 / 10
= 0.08m2
Area for the round duct = π d2
/4
D = sqrt (4A/ π)
D = sqrt (4*0.08/ π)
D = 0.319m
6. Design of base
35 | P a g e
`
lOMoARcPSD|20608229

The base of machine in which all part of the machine rest on it.
The base also considered as a beam. Beam are structural members supporting loads
applied at any points along the members. Beams are usually long, straight prismatic
members. In most cases, the loads applied on the beam are perpendicular to the axis
of the beam. In my design the beam is simply supported that have a load applied on
the center of the axis of the beam this load is perpendicular to the axis of the beam.
DESIGN CONSIDERATION
Material selection = cast iron
Permissible shear stress of cast iron (τ) = 35 N/mm²
Permissible compressive stress of cast iron (σC) = 120 N/mm
The beam is loaded and supported as shown in the figure.
Weight=total weight rest on it is mass of dynamo plus mass of blower plus mass air
filter box for safety we add 50kg
Mass of dynamo 120kg, Mass of air filter box 20kg, Mass of blower 15 kg
For safety 50 kg totally 200kg
Wight =2000N=P , Length =1510mm, Height=120m
Figure 4.2.Base simple beam-Concentrated load at center
P
RA RB
A free body diagram for the beam is shown. The reactions shown on the diagram are
determined from equilibrium equation as follows:
36 | P a g e
`
Figure 4.3.Free body diagram
lOMoARcPSD|20608229

∑ F=0, ∑F= RA + RB
RA + RB = 2000N
RA = 2000N- RB
The two loads are equal and opposite direction from the center load therefore
they are equal in dimension because of they are applied in equal distance from
the center load so that
RA = 1000KN
RB = 1000KN
After determining the loads applied on the beam we can find and draw the
bending moment and shear force diagram of the beam.
In order to calculate the bending moment and shear force we can take the
∑M(at A)=0 ∑M(at B)=0
The bending moment at C can be calculated by
Mc = RA x AC
= 1000N x 755 mm
=750NM
Figure 4.4.Shear force and bending diagram of base
Now the moment of inertia of the section about the central or natural axis given by
I=bh3
37 | P a g e
`
lOMoARcPSD|20608229

=
=mm4
Now by using the relation the relation calculate the induced stress in the material
,
But we have to calculate the allowable stress in order to know the design is safe or
not. The allowable stress is given by
the design is safe.
Base
CHAPTER FIVE
CONCEPT DEVELOPMENT
5.1. Introduction
38 | P a g e
`
Figure 4.5.Base indication
lOMoARcPSD|20608229

The concept of this project includes the flow rate of air which is governed by
continuity equations.it also concludes concepts of electrical motor and centrifugal
blower that are applied in our design process and finally we draw the drawing by
using solid work software.
5.2. Idea generation
We started generating the idea after we observe the problem. We ask the workers and
the coordinators to give us additional concepts for our design. Finally we reach an
agreement to design our project by dappling concept of continuity equation, rotational
energy of the motor, the force analysis. After that we read different books about the
fume extraction, stress analysis for design of material and collect ideas that are
interesting to remove the fume .Finally we design the project in proper manner and
draw using solid work software by using the collected data.
5.3. Evaluation of ideas
Our ideas were evaluated from quantitative prospective. We have evaluated the
capacity of the motor and height that can be delivered. The dimensions of the
centrifugal blower is mandatory for the effective removal of fume and for the valuable
cost of materials
5.4. Concepts
Different concepts are considered for solving the problem. Conservation of energy,
stress analysis and continuity concepts are applied mainly to design. We now the idea
of energy neither created nor destroyed but converted to another form. From this
concept the electrical energy is converted to mechanical energy.
5.5. Concept selection
The concepts that we consider are:
 Material science that tells us to which material we are going to select.
 Continuity equations
 Mathematical concepts that are apply for the design
 solid work
CHAPTER SIX
RESULT AND DISCUSSION
6.1 Result
39 | P a g e
`
lOMoARcPSD|20608229

The result of our design give easily applicable in the in the fabrication work shop by
installing it on CNC plasma machine. Designing this particular product play a great
role on in the shop by creating best environment.
6.1.1 Result of the design procedure
The design procedure leads us to select the appropriate material for each part of the
equipment based on design criteria like cost, availability, efficiency, and durability.
This makes my design suitable and useful in all aspects which in turn to makes the
Equipment easy to use. The design also considers the cost of the material used to
make the equipment. Finally we put all dimension of data in the below table.
Part no Part of fume
extraction
machine
Material selection Value of
Syt (Mpa)
Dimension of
parts or results
1 Air filter Cellulose-Polyester
Blends
L=50cm
H=60cm
t=3inch(76.2mm)
A=0.3mm2
2 Air filter box Stainless steel Syt=505Mpa L=50cm
W=50cm
H=60cm
V=150mm3
3 Bolt Stainless steel Syt=505Mpa M10 And M15
4 NUT For
M10
Stainless steel Syt=505Mpa dc=8mm
h=8mm
5 NUT For
M15
Stainless steel Syt=505Mpa dc=12mm
h=12mm
6 Washer for
M15
Stainless steel Syt=505Mpa Dw=18mm
dw=16mm
t=2.25mm
7 Washer for
M10
Stainless steel Syt=505Mpa Dw=12mm
dw=11mm
t=1.5mm
8 Ac Induction
motor
Squirrel cage AC
electric induction
P=9.9hp
T=29Nm/s
40 | P a g e
`
lOMoARcPSD|20608229

motor
10 Pipe Stainless steel Syt=505Mpa D=0.319m
A=0.08m2
11 Base 35 N/mm² Syt=35Mpa L=1510mm
H=120mm
Table6.1.Results of the design
6.1.2Usage
This machine is widely used in many industrial processes to capture fumes evolved
from reaction vessels. Especially in manufacturing work like CNC machine.
.
6.1.3 Technical principles
. The fume extractor is a machine that uses an electric motor to power a centrifugal
blower. The electric motor provides power for the rotation of the impeller inside the
centrifugal blower which leads to suction of the fume from the CNC cutting machine
table. This fume goes through the pipe into an air filter air box and inside an air filter
box there is an air filter that purifies the fume laden air by extracting poisonous
particles from the fume and then releases a purified air back to the atmosphere. The
fume extractor work on the principle of high-volume air, travelling at low velocity.
6.1.5 Material and manufacturing
We select materials based on strength, cost, and availability. Selection method is
illustrated in methodology section and selected. Material is listed in the above table.
Some part of the machine is easily manufacture in the machine shop of BKMEC like
air filter box, pipe, washer, bolt and nut, impeller, air filter, volute casing. But an
electric motor related to it is directly buy from the market.
6.1.6. Safety
41 | P a g e
`
lOMoARcPSD|20608229

 Turns on the motor only when the CNC machine start to work to increase the
life time of blower
 When the user use air filter for a long time there is accumulation of dust
particle on it this cause to restrict flow fume as a result efficiency of filtration
system so we must sweep air filter once per two day after we finish the work
to keep their efficiency and to increase their life.
 When the user want to change the part of the machine in case of failerty or
whatever case should buy the part like the previous.
6.2. DISCUSTION
6.2.1 Project out come
We think that this project solve the problem related to fume in the material
preparation and fabrication shop of BKMEC.as a result the working environment is
good and the company economic growth increased by one step because all worker are
their job in full capacity.
6.2.2. Lesson learnt
During design of this project, many conceptual knowledge was taking consideration
which led us to calculate and analysis the force exerted on the component of fume
extraction machine .this project gave us the exposure to the solid works mechanical
design any idea in your mind .here also, we have been doing in a group of four
students and it was a great experience of working in a team.
6.2.3. Process
When we had work in material preparation and fabrication shop. All worker including
our does not feel comfort because of fume that leave from CNC machine especially
the operator CNC machine. Then we generate the idea of, why don’t we design a
machine to suck these fume from the CNC machine. After these explore what type of
material are used to manufacture the machine and selected appropriate materials.
Then we are starting the design.
6.2.3.Use of Methods
42 | P a g e
`
lOMoARcPSD|20608229

For the project the material is checked then the safety based on the designed
Dimensions and in other parts first we calculate the appropriate dimensions then the
Safe materials are selected.
6.2.4. Future Development
For the future we shall design some additional systems which improves the machine
to work fully automatic by the aid of sensors and actuators which means the fume
extractor machine is start when the CNC machine is start. We also think in the future
to extend it in to extract fume from welding machine by modification some design of
machine.
CHAPTER SEVEN
CONCLUSION AND RECOMMENDATION
Conclusion
The present work deals with reduction of emission rate of plasma CNC fumes and
create a better health environmental during the welding process in technical institute
and industrial application. As concerned with design results the emission rate like
43 | P a g e
`
lOMoARcPSD|20608229

oxides of Sulphur, Oxides of Nitrogen, Carbon monoxide and Carbon Dioxide has
been reduced, when the filter has been installed to the fumes Extraction System.
The design of the fume extractor is achieved with a thorough study and research of
centrifugal blower. The overall design calculation is done with the consideration of
industrial material standards of ASHRAE and ASME. The fume extractor will have a
high level of performance in the extraction of fume particles. The calculated design
power of the motor is 9.9 hp but for availability a 10 hp motor can be used with
adequate power. The machine is easy to operate and require no special technical
training on how to operate it. It will be coated with corrosive resistant aluminum
silver spray paints.. This machine can be used for extraction of fumes, smokes and
small particles while CNC PLASMA MACHINE work.
Recommendation
We strongly recommend the company to do whatever it takes to put this fume
extractor machine into work. Highly toxic substances are released with fumes which
cause a serious injury in the internal and external organs of the body. The machine we
have built is strongly recommended because it has the capability extract fume from
plasma cutting machine that dangerous for the operator it may cause cancer.
Reference
[1] Mansour A. B. and Mohammad K. G. (2010) “Total Fume and Metal
Contaminations During Welding in Selected Factories in Jeddah, Saudi Arabia.
International Journal of Environmental Research and Public Health”, Vol. 7, No 7,
pp. 2978-2987.
[2] IOP Conf. Series: “Materials Science and Engineering 413 (2018) 012018”
44 | P a g e
`
lOMoARcPSD|20608229

[3] M. J. Omoregie1, *, T. I. F.- Akilaki and K. E. Kalu “Nigerian Journal of
Technology (NIJOTECH)”
[4] R.S. Khurmi and J.K. Gupta (Naqash), “A Textbook of Machine Design”, 2005
[5] Babalola Philip Olufemi and Oriyomi Moses Oluwayimika “2018 IOP Conf. Ser.:
Mater. Sci. Eng. 413 012018”
[6] ASME Research Committee on Fluid Meters (1961). Flowmeter Computation
Handbook. New York: The American Society of Mechanical Engineers.
[7]https://www.hkdivedi.com/2019/10/velocity-triangle-for-centrifugal-fan.html?m=1
[8]https://pubmed.ncbi.nlm.nih.gov/22459321/
Appendix
45 | P a g e
`
lOMoARcPSD|20608229

Fig top view assemble drawing
Fig front view
46 | P a g e
`
lOMoARcPSD|20608229

project-fum-final-fume-extractor-for-cnc-machine.pdf

Recommended

Recommended

More Related Content

Similar to project-fum-final-fume-extractor-for-cnc-machine.pdf

Similar to project-fum-final-fume-extractor-for-cnc-machine.pdf (20)

Recently uploaded

Recently uploaded (20)

project-fum-final-fume-extractor-for-cnc-machine.pdf