Design And Construction An Electric Muffle Furnace

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                         BACKGROUND OF THE PROJECT

This work is on an electric muffle furnace which is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash. [C.A. Crowley, 1937] After the development of high-temperature heating elements and widespread electrification in developed countries, new muffle furnaces quickly moved to electric designs. [C.A. Crowley, 1937]

Historically, small muffle ovens were often used for a second firing of porcelain at a relatively low temperature to fix overglaze enamels; these tend to be called muffle kilns. The pigments for most enamel colours discoloured at the high temperatures required for the body and glaze of the porcelain. They were used for painted enamels on metal for the same reason.

Today, a muffle furnace is a front-loading box-type oven or kiln for high-temperature applications such as fusing glass, creating enamel coatings, ceramics and soldering and brazing articles. In ceramics muffle kilns were typically used for relatively low temperatures, for overglaze decoration. They are also used in many research facilities, for example by chemists in order to determine what proportion of a sample is non-combustible and non-volatile (i.e., ash). Some models incorporate programmable digital controllers, allowing automatic execution of ramping, soaking, and sintering steps[C.A. Crowley, 1937]. Also, advances in materials for heating elements, such as molybdenum disilicide, can now produce working temperatures up to 1,800 degrees Celsius (3,272 degrees Fahrenheit), which facilitate more sophisticated metallurgical applications.

An electric muffle furnace is usually heated to desired temperatures by conduction, convection, or blackbody radiation from electrical resistance heater elements. Therefore, there is no combustion involved in the temperature control of the system, which allows for much greater control of temperature uniformity and assures isolation of the material being heated from the byproducts of fuel combustion.

1.2                                                  PROBLEM STATEMENT

The heating means of conventional furnace is only done thermally which becomes a problem when the means of generating the heat is not available. In other to overcome this challenge a muffle furnace was invented, which is an enclosure in which energy in a non-thermal form is converted to heat, especially such an enclosure in which heat is generated by the combustion of a suitable fuel. The furnace is usually heated to desired temperatures by conduction, convection or blackbody radiation from electrical resistance heating elements

1.3                                     AIM AND OBJECTIVES THE PROJECT

The main aim of this work is to build a piece of oven-type equipment that can reach high temperatures. It usually works by putting a high-temperature heating coil in an insulated material. The insulating material effectively acts as a muffle, preventing heat from escaping.

1.4                                          APPLICATION OF THE PROJECT

Today, an electric muffle furnace is usually a front-loading box or tube design used for high-temperature applications such as melting glass, creating enamel coatings, technical ceramics or soldering and brazing. They are also used in many research facilities to determine what proportion of a sample is non-combustible and non-volatile (i.e. ash)..

1.5                                         SIGNIFICANCE OF THE PROJECT

An electric muffle furnace is made of standard quality materials which make it durable, reliable and perfect for long time use. The outer case or cabinet of this muffle furnace is made of thick PCRC sheet. The case is painted with stove enable that keeps the unit rust free. Electric muffle furnace provides accuracy and reliability, set point and actual temperature dual display.

1.6                                                 SCOPE OF THE PROJECT

An electric muffle furnace has an externally heated chamber, the walls of which radiantly heat the contents of the chamber, so that the material being heated has no contact with the flame. Muffle furnaces are most often utilized in laboratories as a compact means of creating extremely high-temperature atmospheres. They are employed to test the characteristics of materials at extremely high and accurate temperatures. A muffle furnace is also known as a retort furnace.

1.7                                                        METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. programming of microcontroller
2. Design and calculation for the work was carried out.
3. Studying of various component used in circuit.

• Construct the whole circuit.
• Finally, the whole device was cased and final test was carried out.

1.8                                                         PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.