DESIGN AND FABRICATION OF A SIMPLE LOW-COST WASHING MACHINE SUITABLE FOR WASHING POLYETHYLENE MATERIALS
1.1. BACKGROUND OF STUDY
Industrial and domestic application of polyethylene materials is on the increase and they are non-biodegradable materials ,as thus they are best recycled.
Waste generally render our environment unfriendly and the worst of them all are those waste that are non-biodegradable and as such, waste of these forms (non-biodegradable) pose a serious threat to our environment.
One of these categories of non-biodegradable waste is pure water sachets. They are found in virtually every part of Nigeria and various attempts have been made to biodegrade most pure water sachets. Most plastics and polythene / pure water nylon wastes are usually thrown in public drains, roads and open places to public view in most parts of the country
These wastes are used at times as a combustion aid for burning other organic refuse and this liberates toxic vapours or gases that pollute the air and causes inconveniences to residents living near the landfill sights. (New, 1986). Their values as reclaimed or recycled waste is considerably higher than their values as energy source (Andrew and Subramaman, 1992). Accordingly, well – known destructive techniques such as incineration or pyrolysis (Leidnor, 1981), seem quite wasteful, and hence, recycling of plastic wastes is the best method for solving both the environmental and economic problems associated with plastic waste disposal.
Recycling of plastic waste is rapidly developing in almost every society and this is largely based on the environmental awareness, need to conserve materials and energy, and growing demand to increase production economy (La Mantia, 1993 and Chatterjee and Kumar, 2009). Many private industries and few government agencies are now engaging in recycling of plastic and polythene/nylon wastes.
Recycling of plastic/nylon waste could be achieved through chemical or mechanical recycling method. The chemical means involve sow out recycling process (Kmpouris et al; 1995), floatation (Dilly.louis, 1999) and selective dissolution techniques (Herbery et al; 1992). On the other hand, mechanical recycling involves the use of machines in converting the waste into recycle products, which can be re-used in now application (Jost, 1995). Recycling of plastic using machines involves washing, shredding, extruding and injection molder. A washing machine is used in washing polythene materials as a way to reduce the manual labour spend and to wash the polythene material effectively and it saves time.
Loading condition is important in designing a washing machine. Efficiency and Other Factors
May vary due to net loading conditions. Generally there are two types of loading condition. Can be seen in washing machine.
1.2. STATEMENT OF THE PROBLEM
Recycling of polythene material requires that the materials be free of impurities such as oils, dust etc. This project seeks to address this by developing a washing machine for the purpose of recycling of polythene material. Washing of polyethylene material with our hands may result to the following problems e.g. inefficiency, time and labour cost. The primary motivations for development of a polythene washing machine is to save time and labour, and to improve speed and efficiency.
1.3. AIMS AND OBJECTIVES OF THE WORK
1.3.1. AIM OF PROJECT
To develop a simple low cost washing machine suitable for washing polyethylene materials.
1.3.2. OBJECTIVES OF THIS PROJECT
The following are the purpose for which this design project will meet the aim mentioned above.
i) To select materials available locally suitable for respective components of the machine
ii) To Determine Optimum dimensions of the different components
iii) Fabricate the machines based on designed dimensions.
iv) Test the machine to determine efficiency and effectiveness in comparison to manual washing.
1.4. SIGNIFICANCE OF THIS PROJECT
Waste generally render our environment unfriendly and the worst of them all are those waste that are non-biodegradable and as such waste of these forms post a serious threat to our environment.
⦁To wash manually requires too much time ,effort, and man power.
⦁ Traditional washing are in-efficient.
⦁ High level of waste polyethylene materials calls for need to recycle these materials.
⦁ Burning of these materials causes green gas effect and air pollution
⦁ Waste of land transportation resources when use for landfill purposes.
1.5. SCOPE OF THIS PROJECT
This work is delimited to the design and fabrication of washing machine suitable for recycling of polyethylene materials.
2.0. LITERATURE REVIEW
Polyethylene or polyethene (also known as PE) is the most common of plastics. The annual global production is around 80 million tones. Its primary use is in packaging (plastic bags, plastic films, geomembranes, containers including bottles, e.t.c).
2.1.1 CLASSIFICATION OF POLYETHYLENE
Polyethylene is classified by its density and branching. Its mechanical properties depend significantly on variables such as the extent and type of branching, the crystal structure, and the molecular weight. There are several types of polyethylene:
I. Ultra-high-molecular-weight polyethylene (UHMWPE)
II. Ultra-low-molecular-weight polyethylene (ULMWPE or PE-WAX)
III. High-molecular-weight polyethylene (HMWPE)
IV. High-density polyethylene (HDPE)
V. High-density cross-linked polyethylene (HDXLPE)
VI. cross-linked polyethylene (PEX or XLPE)
VII. Medium-density polyethylene (MDPE)
VIII. Linear low-density polyethylene(LLDPE)
IX. Low-density polyethylene(LDPE)
X. Very-low-density polyethylene(VLDPE)
XI. Chlorinated polyethylene (CPE)
With regards to sold volumes, the most important polyethylene grades are HDPE, LLDPE, and LDPE.
2.1.2 LOW-DENSITY POLYETHYLENE (LDPE)
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its manufacture employs the same method today. The EPA estimates 5.7% of LDPE (recycling number 4) is recycled. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2013 the worldwide LDPE market reached a volume of about US$33 billion.
2.1.3 PROPERTIES OF LOW-DENSITY POLYETHYLENE
LDPE is defined by a density range of 0.910–0.940 g/cm3. It is not reactive at room temperatures, except by strong oxidizing agents, and some solvents cause swelling. It can withstand temperatures of 80°C continuously and 95°C for a short time. Its molding temperature is from 50C to 50 0C. Made in translucent or opaque variations, it is quite flexible, and tough but breakable. LDPE has more branching (on about 2% of the carbon atoms) than HDPE, so its intermolecular forces (instantaneous-dipole induced-dipole attraction) are weaker, its tensile strength is lower, and its resilience is higher. Also, since its molecules are less tightly packed and less crystalline because of the side branches, its density is lower.(Wikipedia).