East African Scholars Journal of Engineering and Computer Sciences

Abbreviated Key Title: East African Scholars J Eng Comput Sci

ISSN 2617-4480 (Print) | ISSN 2663-0346 (Online) |
Published By East African Scholars Publisher, Kenya
Volume-2 | Issue-2 | February-2019 |

Research Article

Fabrication and Performance Evaluation of Designed Multipurpose

Domestic Gas Baking Oven
1 1
Akinnuli , Basil Olufemi
1
Department of Industrial and Production Engineering, Federal University of Technology PMB 704, Akure Ondo State, Nigeria.

*Corresponding Author
Akinnuli

Abstract: Akinnuli and Caleb designed a multipurpose domestic gas baking oven due to irregular power supply common
in developing countries. The study reported the design and predicted cost of production of a proposed domestic gas oven.
The simulation, fabrication and performance evaluation of the proposed machine were left. The proposed gas oven was
limited to its design concept and predicted production cost. This study made use of their drawings as well as their design
analysis values which are : outer dimension 860 mm length × 660 mm width × 1150 mm height and the inner dimension
is 759 mm length × 559 mm width × 835 mm height. Proposed material to be used are mild steel and fiber glass as an
insulator. Total cost of its production was predicted to be N56, 470.00 ( $156.86 as at time of the design concept at the
exchange rate of N360.00 to a Dollar). This study find out the level of reality, produce-ability , and performance level
involved in this design concept by fabricating the designed oven and evaluate its performance to determine its,
functionality, use-ability and marketability. When the gas baking oven was tested, high efficiency was obtained. The
performance test gave oven efficiency of 90.7 per cent. The oven can be adapted for both domestic and industrial
purposes and have been found very useful in bakery industries. Actual amount spent for the oven production was N
59,880.40 ($166.33) compared to the proposed cost of N56, 470.00 by designers which is about 5.69% increase, this
might have been change in some material cost in the market. The oven can be adapted for both domestic and industrial
purposes and have been found very useful in bakery industries. Therefore, it can be deduced that the designed project is
cost effective, faster and thus bakes and roasts effectively.
Keywords: multipurpose, gas oven, cost, fabrication , performance evaluation, functionality establishment.

INTRODUCTION baking process and equipment have been conducted for

A baking oven is the most widely used minimizing energy consumption (Therdthai et al.,
appliance in food service industry. An oven can be 2003). The first historical record of an oven being built
simply described as a fully enclosed thermally insulated is in 1490, in Alsace, France. This oven was made
chamber use for the heating, baking or drying of a entirely of bricks and tile (Mary,2017). Count Rumford
substance (Merriam-Webster Dictionary, 2011). The (aka Benjamin Thompson) invented a working iron
moisture in the food material simultaneously diffuses kitchen stove that was designed for very large working
with continuous movement of the oven ambient air kitchens (Rumford, 1928).
(Tong and Lund 1990; Ozilgen and Heil 1994) and
between the product and its environment (Carvalho and One successful and compact cast iron design
Martins 1993), which theoretically are well known. was Stewart’s Oberlin iron stove, patented in 1834. The
Commercially, ovens are available in the various evolution of gas stoves was delayed until gas lines that
configurations like electric ovens, micro oven and wood could furnish gas to households became common
oven etc. (Mary, 2017). The microwave ovens were a byproduct
of another technology (Mary, 2017). The significance
Study of baking oven is important because it attached to this research is to investigate the
could lead to a more efficient process of baking functionality of already designed gas baking gas oven
favorable to energy efficiency and better product by fabrication and evaluate the performance of the
quality (Fellows, 2000). Analysis and optimization of
Quick Response Code Journal homepage: Copyright © 2019 The Author(s): This is an open-
http://www.easpublisher.com/easjecs/ access article distributed under the terms of the
Creative Commons Attribution 4.0 International
Article History License (CC BY-NC 4.0) which permits unrestricted
Received: 24.01.2019 use, distribution, and reproduction in any medium
Accepted: 10.02.2019 for non-commercial use provided the original author
and source are credited.
Published: 25.02.2019
DOI: 10.36349/easjecs.2019.v02i02.001

Published By East African Scholars Publisher, Kenya 47

Akinnuli & Basil Olufemi; East African Scholars J Eng Comput Sci; Vol-2, Iss-2 (February, 2019): 47-52
oven. Since fabrication and performance evaluation of
the existing designed oven was carried out in t
his research, little was done on literature
review.

METHODOLOGY
The method used here involve : Adoption of
the existing engineering drawing and the designed Figure 2: Orthographic View of the Gas oven
values, of the designed oven, fabrication, performance
evaluation as well as the current cost estimate for the Explosive drawing of the designed oven.
proposed oven.

Assembly view of the Gas Oven

Figure-3: Exploded View of the Gas oven

Figure 1: Assembly View of the Gas oven
Table-1: Component Parts of the Oven
Orthographic view of the Gas Oven (Front view, ITEM COMPONENT QUANTITY
Side view and Top View) NO.
1 Tray 3
2 Gas valve or regulator 1
3 Handle 2
4 Frame 1
5 Burner 1
6 Perforated plate 1
7 Oven door 1
8 Oven firing door 1
9 Chimney or vent 1
10 Caster wheel or rollers 4
11 Thermometer 1

Figure 4a : Fabricated Gas oven Figure 4b Thermometer

The gas oven was fabricated with the use of layers, the body (outer layer) is made of well coated
indigenous material according to the conceptual design. mild steel of thickness 1mm with the dimension
The oven consists of housing unit (frame), 860×660×1150 (Length × Width × Height respectively)
thermometer, gas regulator, tray, oven door and oven in mm, inner layer is made of mild steel of thickness
firing door, perforated plate, heating gas burner, 1mm with the dimension from the end of the perforated
chimney or vent, rollers. The housing unit which is the sheet 759×559×835 (Length × width × height
frame represents the entire out look of the baking oven. respectively) in mm. Fiber glass of thickness 40 mm is
The housing unit of the gas oven was made up of three the lagging material (insulator) which is stuffed in-

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Akinnuli & Basil Olufemi; East African Scholars J Eng Comput Sci; Vol-2, Iss-2 (February, 2019): 47-52
between the outer layer and inner layer and which acts
as a thermal insulating material to prevent loss of heat Three trays were provided in the baking
(insulation), from the inner baking chamber to the chamber of the oven, each having the dimension of
outside and also ensure even baking of the product in 770×570 (length × width respectively) in mm,
the baking chamber, and this fiber glass makes up the galvanized wire mesh was welded to provide base or
middle layer of the gas oven. Fiber glass is known to support for the baking trays and the oven works by
have light weight, high strength and high thermal shock natural convection; it helps for the movement of hot air
resistance characteristics. from the lower tray to the upper tray of the oven. The
distance between the top of the oven and the upper tray
The oven has two door chambers. The upper was kept at 230 mm, also the distance from the upper
door chamber of the gas oven was made up of mild tray to the middle tray was kept at also 230 mm and
steel and fiber glass of thickness 40 mm was placed in also the same distance (230 mm) was kept between the
between the steel plate to avoid the loss of heat through middle tray and lower tray, while the distance between
the door and in front of the door was provided with a the lower tray and the base of the oven was kept at a
heat treated (resistive) glass which can withstand very height of 410 mm.
high temperatures to monitor the baking product inside
the oven without opening the door. And the lower door Principle of Operation
chamber also known as oven firing door houses the The major operational principle of the
burner compartment. Inside the oven firing door is an fabricated gas oven is the process of heat transfer. Heat
oven burner stand on which the burner is welded to, the transfer tends to occur whenever there is a temperature
stand kept at a height of 190 mm from the ground level difference, and the ways in which heat may be
so that an opening is created under the body in the same transferred in the gas oven that is convection.
direction with the burner to enable the entrance of
required amount of air (oxygen) for easy and neat Convection is the transfer of energy from one
burning/combustion of the gas flame. The opening of place to another by the motion of a mass of materials
about 200 mm by 200 mm length by width respectively between the two points. Convection occurs when
is created through which the burner head is connected particles with a lot of heat energy in a liquid or gas
to the gas pipeline / hose i.e. Gas inlet. It is regulated move and take the place of particles with less heat
with gas knobs. energy. Heat energy is transferred from hot places to
cooler places by convection (BBC – GCSE Bitesize,
The oven burner is an O shaped pipe 2014). Naturally, convection occurs when a solid
drilled/perforated with small opening at intervals. It is surface is in contact with a fluid of different
mounted inside the oven lower chamber and tightened temperature from a surface. Density differences provide
with nuts and bolts. Perforations are created just below the force required to move the fluid (moisture) in the
the burner to allow for heat dissipation. Heat energy is food. In the oven, the fluid involved is the enclosed air
caused to escape through holes created just below the and the burner surface, which provides the solid
burner and circulates round the oven chamber. The base surface, while the oven walls serve as the solid surfaces.
of the inner baking chamber was provided with a
deflector plate of the thickness of 1mm with dimension Usually this equipment has a gas inlet through
of 800×580 (length × width) mm placed at a height of which it is connected to a medium size gas cylinder via
280 mm from the base of the oven to avoid the direct a regulator with low pressure flexible hose. The
flame coming from the burner to the baking chamber regulator of gas flow rate into the pipeline from the gas
and to provide even distribution of the heat throughout cylinder is turned open.
the baking chamber.
With gas in the pipeline, the gas burner is
The thermometer was attached to a drilled activated by turning on the temperature knob after
surface on top of the oven. The thermometer sensor was turned on from the gas cylinder. This creates a gap
placed in the center portion of the baking chamber to through which the gas rushes to the nozzle. The gas
ensure that the thermometer should detect the then passes through the nozzle after which the pressure
temperature of the both the lower and the upper layer of drops with increased velocity. The low pressure high
the baking oven. The oven is also provided with a velocity gas then flows into the burner gas compartment
vent/chimney at the top of the baking oven connected together with the air (oxygen) from the opening created
from the inner baking chamber for the continuous below the oven stand into a channel where it spreads
removal of hot and humid air from the inner baking out through the holes around the burner to glow in
chamber. The baking oven was provided with the flame when lighted up by a lighter. The intensity of the
handles in both the sides for mobility, easy carriage and heat generated from the flames depends on the amount
to prevent the rollers (wheels) from wearing out due to of gas that is being burnt. The gas flow rate is altered or
bad terrain. The oven supports have rollers for easy controlled by the continuous adjustment of the valve
movement and to absorb shock as well as sustain the (gas knob).
weight of the oven.

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The pre – set of the gas regulator has made it
possible to obtain a stoichiometric mixture with a Different sizes of dough were baked to examine the
constant flow at various level of gas flow rate. This effect of dough size on baking time. Figure 6 shows the
continuous adjustment has therefore provided a wider result obtained.
limitation of range whereby the equipment can be
operated provided that the temperature gauges still
accommodate that.

Performance Evaluation
The gas baking oven after fabricated was put
to test in order to determine its functionality and the
effectiveness through baking some food items like
bread and meat items.

Baking of bread
Breads of different sizes were baked in the gas
oven at a temperature range of the 170-180˚C.The time Figure-7: Size of dough vs. Baking Time
taken by the gas oven for the baking of the breads is Source: Study, 2017
shown in Table-2
DISCUSSION
Table-2: Baking Time of the Bread There is observed sharp increase in baking
Product Size Time Taken For time as the weight of dough increases. This is quite
Baking at 170- understandable since as the dough size increases more
180˚C time is needed for sensible heat to penetrate the dough.
Bread dough 300 grams (0.3 30 minutes It is further observed that there is less marginal increase
(small size) kilograms) in baking time as the size of dough is increased beyond
Bread dough 400 grams (0.4 37 minutes a certain point. Too much heat will burn the dough
(medium size) kilograms) whilst leaving the inside undone. In industrial (large)
ovens, baking time can be improved a great deal by
introducing forced air to increase heat flux within the
system.

The high efficiency record of 90.7% can be

attributed to the 20 per cent allowance for sensible heat
transfer considered in the design.

Estimated /Actual Production Cost

The proposed design values were un-bolded
Figure-5 : Baking of Bread in the oven figures while the actual fabricated values as at time of
Source: Study, 2017 fabrication were bolded in Table 4.

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Bill of Engineering Measurement and Evaluation (BEME)

Table -4: Material Cost

S/N QUANTITY MATERIAL DESCRIPTION UNIT COST TOTAL
COST
1 3 Mild steel sheet metal (1mm) N2, 000.00 N 6,000.00
N2,240.00 N 6,720.00
2 1 Roll of fibre glass N 3, 500.00 N 3, 500.00
N 3,920.00 N 3,920.00
3 1 Temperature sensor / N 2, 500.00 N 2, 500
thermometer N N2,800.00
2,800.00
4 1 Gas burner N2, 800.00 N 2, 800
N 3,136.00 N 3,136.00
5 4 Length 40 x 40 square pipe N 450.00 N 1800.00
N 504.00 N 2,016.00
6 2 Angle iron N 875.00 N 1750.00
N 980.00 N 1,960.00
7 4 Lock bolt (10mm) N 30.00 N 120.00
N 33.60 N134.40
8 1 Handle N 250.00 N 250.00
N 300.00 N 300.00
9 1 Filler N 1500.00 N 1500.00
N 1,680.00 N1,680.00
10 2 Sand paper N 125.00 N 250.00
N 140.00 N 280.00
11 2 Yards gas hose N 200.00 N 400.00
N 224.00 N 448.00
12 2 Clips N 50.00 N 100.00
N 56.00 N 112.00
13 1 Gas regulator N 1, 000.00 N 1, 000.00
N 1,200.00 N 1,200.00
14 1 Gas cylinder (3kg) N 4, 500.00 N 4, 500
N 5040.00 N 5040.00
15 Gas N 500.00 N 500.00
N 560.00 N 560.00
16 1 (240 pieces Electrode (gauge 12) N 1, 500.00 N 1, 500.00
in a pack) N 1,680.00 N 1,680.00
17 3 Drill bit (5m) N 150.00 N 450.00
N1,68.00 N 504.00
N28, 420.00
N 31,830.40
Note: The bolded figures are the fabricated cost while the un-bolded figures are the designed cost.

Total Design Cost = N 13, 000.00

Total Material Cost Proposed is (N 28,420.00) Machine Cost = N 1, 050.00
WHILE ACTUAL COST IS N 31,830.40
Labour cost Typing and Binding = N 5, 000.00
Cost Per hour = N450.00
Number People =4 Total Engineering Evaluation of the Gas Baking
Working Hours = 5 hours Oven
Labour cost for 4 people = (5 x 450) x 4  Material Cost = N 31,830.40 (N
= 2250 x 4 = N 9, 000.00 28,420.00)
Total Labour Cost = N9, 000.00  Labour Cost = N 9, 000.00
 Design Cost = N 13, 000.00
Design Cost  Machine Cost = N 1, 050.00
3D Solidworks software = N 5, 000.00  Typing and binding = N 5, 000.00
Simulation using ANSYS = N 8, 000.00

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TOTAL COST = N 31,830.40, (N 28,420.00) + N 9, the bakery products with good quality parameters like
000.00 + N 13, 000.00 + N 1, 050.00 color, texture and the taste and good volume in the
+ N 5, 000.00 fermented products and also the pre heating time of the
gas oven was also reduced this in turn consumes very
TOTAL COST = N 59,880.40 ( $166.33) ; ( N56, less energy and the time of the baking and reduces the
470.00; $156.86.). The Dollar values was based on the overall working cost. This can be used for small
exchange rate of N 360 per USSD as at the time of this entrepreneurs and can be popularized in areas where
fabrication. power cuts are more frequent and power is available for
limited hours. The design and construction of this
The percentage cost change for the proposed project has been satisfactorily completed with the
design value is capability of providing high performance heat energy
(N 59,880.4 - N56, 470.00 / N 59,880.40) X 100 = for effective baking. The design of the gas baking oven
5.69% was produced with locally soured raw materials in its
totality, with the exception of bimetallic thermometer,
RESULTS AND DISCUSSION sensor and knobs due to their scarcity.
The the fabrication of the designed oven was
accomplished and performance of the oven was Nevertheless, the designers cannot claim that
evaluated the following were deduced from the the gas baking oven is hundred percent efficient, since
evaluation: Oven of ( 860 x 660 x 1150) mm external from the knowledge of thermodynamics, it is
dimension, ( 759 x 559 x 835) mm internal dimension impossible for any heat transferring device to deliver
was fabricated using 1 mm thick mild steel sheet. This heat with a 100% efficiency due to some heat losses.
system was incorporated with thermometer for oven But the designers ensured that a good finish was given
temperature measurement and lagged with fiber glass of to the design and development of the equipment.
40 mm thick. Average time for baking 300g of dough
for bread was 35 minutes while for 400g average time REFERENCES
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© East African Scholars Publisher, Kenya 52