Design And Construction Of Electric Blower For Furnace

ABSTRACT

During furnace operation, air is the utility that should be available at all time in order to ensure a smooth and standardized operation.

Supplying air manually will reduce productivity and more man hour to accomplish a given task.

Thus, an electric blower was designed in this regard with an efficient electric motor as the driver. The suction conditions and other application data are appropriately used to calculate the design parameters such as: suction specific speed, the power input to the blower, the inlet and outlet velocity, the twisting moment of the impeller shaft etc.

The principle adopted in this design is that the impeller was made of a close type because of the level of pressure needed to carry out blowing operations in a furnace. The blower was designed to convert driver energy to kinetic energy by accelerating it to the outer rim of the impeller and the impeller driven by the connecting shaft adds the velocity component to the air by centrifugally casting the air away from the impeller vane tips.

TABLE OF CONTENTS

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWLEDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.1      INTRODUCTION

1.2      APPLICATION OF ELECTRIC BLOWER

1.3      SIGNIFICANCE OF THE PROJECT

1.4      SCOPE OF THE PROJECT

1.5      LIMITATION OF THE PROJECT

CHAPTER TWO

2.0     LITERATURE REVIEW

2.1      REVIEW OF THE STUDY

2.2     REVIEW OF DIFFERENT TYPES OF BLOWER

2.3      OVERVIEW OF A FURNACE

2.4      CATEGORIES OF FURNACE

CHAPTER THREE

3.0     CONSTRUCTION METHODOLOGY

3.1      SYSTEM HOUSING

3.2      SYSTEM MOTOR  FIXED WITH THE FAN

3.3      WORKING PRINCIPLE

3.4      SYSTEM WIRING

CHAPTER FOUR

RESULT ANALYSIS

4.0      CONSTRUCTION PROCEDURE AND TESTING

4.1      CASING AND PACKAGING

4.2      ASSEMBLING OF SECTIONS

4.3      DESIGN LIMITATION

4.4      ELECTRIC UTILITY TEST RESULTS

4.5      SAFETY REQUIREMENTS

4.6      CHANGE MOTOR SPEEDS

4.7      REPLACING THE BLOWER MOTOR

4.8      FINAL SYSTEM CHECKOUT

CHAPTER FIVE

5.0      CONCLUSION

5.1      REFERENCES

CHAPTER ONE

1.0                                                              INTRODUCTION

The blowers in furnaces typically move the heated air through a duct system that distributes heat and then returns it to the furnace. Usually the blowers are double inlet models with the inlets to the centrifugal blower at both sides. The motor mounts inside the inlet cone on one side. If a house has central air-conditioning, the same blower is usually used to move the cooled air throughout the house.

Although furnaces, air conditioners and heat pumps have become significantly more efficient over the last couple of decades, residential forced air system blowers have not experienced similar improvement. The most common blowers have been shown by in-field testing to  have efficiencies of only 10% to 15% (Phillips 1998 & 1995 Gusdorf et al. 2002). These low efficiencies indicate that there is significant room for improvement of both electric motor and the aerodynamic performance of furnace blowers.

An important consideration in analyzing forced air system blowers is that essentially all of the wasted electricity is manifested as heat. This extra heat reduces air conditioning cooling and dehumidification performance and effectively acts as fuel switching for fossil fuelled furnaces. For electric furnaces, this heat substitutes directly for the electric resistance heating elements. For heat pumps, this heat substitutes for vapor compression-based high COP heating and effectively reduces the COP of the heat pump.

In this study, the aim is to characterize the performance of electric furnace blowers to determine typical energy consumption, how performance differs between standard laboratory rating conditions and real life applications, what attributes of blowers contribute significantly to their performance, and to use this information to evaluate proposed performance testing.

1.1                                             OBJECTIVE OF THE PROJECT

The objective of the project is to fabricate an electric device that is used to produce consistent air supply to the base of the fire to aid the combustion process.

1.2                                         SIGNIFICANCE OF THE PROJECT

The electric blower is one of the most important and portable tools in a blacksmith’s workshop. The function of the blower is to deliver a consistent air supply to the base of the fire to aid the combustion process. Supplying the fire with oxygen means that the fire can get to a temperature hot enough to manipulate and craft iron objects – without a consistent supply of oxygen, this task is nearly impossible.

1.3                                     APPLICATION OF ELECTRICBLOWER

This work is used for local and industrial use for shaping or bending of metal. Electric blower is one of the most important and portable tools in a blacksmith’s workshop which is also used in electric furnace.

1.4                                                 SCOPE OF THE PROJECT

In the early days, it was common for a blacksmith’s apprentice to use their lungs to blow air into a hollow tube, directly into the base of the fire. This method was not very effective as the majority of the oxygen they inhaled would get absorbed by the lungs, and the exhalation contained a lot of carbon dioxide which did not help the fire. This was not an effective method. It was this reason that forge blower was introduced. The blower was designed to convert driver energy to kinetic energy by accelerating it to the outer rim of the impeller and the impeller driven by the connecting shaft adds the velocity component to the air by centrifugally casting the air away from the impeller vane tips.

Parts produced by forging are stronger than casted or machined parts. During the forging process the internal grain of the part changes its form and continuous forging for a few minutes strengthens the part’s characteristics.

This device has been built. This includes identifying suitable performance metrics and target performance levels for use in standards. Five different combinations of blowers and residential furnaces were tested for air moving performance. Three different types of blower and motor combinations were tested in two different furnace cabinets. The blowers were standard forward–curved impellors and a prototype impeller.  The testing operated each blower and furnace combination over a range of air flows and pressure differences to determine air flow performance, power consumption and efficiency. Additional tests varied the clearance between the blower housing and the furnace cabinet, and the routing of air flow into the blower cabinet.\

1.5                                           LIMITATION OF THE PROJECT

• This device prevents work hardening and hence increases the difficulty of performing other machining operations on the part.
• Producing forged parts involves a lot of expenditure for the machinery, dies, tools and personnel.
• Some forging requires metal-forming dies, which are required to be precisely machined and heated to properly shape the piece. This is not always achievable by novices or not very-high experienced engineers.