Rajan Wilcox
Plastic fuel tanks, also known as poly fuel tanks or polyethylene tanks, are used to store and transport flammable substances such as gasoline, butane, motor oil, and natural gas. They are made from a variety of materials, typically including high-density polyethylene (HDPE), polypropylene (PP), regrind plastic, and ethyl vinyl alcohol (EVOH). The tanks are designed to be strong, durable, and reliable, with some featuring multiple layers for added strength and to meet stricter emission standards. The manufacturing process involves rotational molding or blow molding, creating a seamless one-piece construction that can hold several gallons of substances for extended periods.
| Characteristics | Values |
|---|---|
| Common materials used | High-density polyethylene (HDPE), Polypropylene (PP), Regrind plastic (recycled polyethylene), Plastic adhesive, Ethyl vinyl alcohol (EVOH) |
| Manufacturing process | Rotational molding, Blow molding |
| Pros | Safe storage and transportation of flammable substances, Gauging substance levels, Venting, Feeding the engine, Anticipating potential harm |
| Cons | More susceptible to weakness in the walls than rotationally molded tanks |
| Common flammable substances stored | Gasoline, Butane, Motor oil, Transformer oil, Gas oil, Natural gas |
| Other names | Poly fuel tanks, Polyethylene tanks |
| Multilayer tank technology | Used to meet stricter emission standards, e.g., Ford's six-layer fuel tanks |
| Density | Minimum: 0.945 g/cm3, Maximum: 0.952 g/cm3 |
| MFR | Minimum: 3.3 g/10 min, Maximum: 4.0 g/10 min |
Explore related products
What You'll Learn
Plastic fuel tanks are often made from high-density polyethylene (HDPE)
The manufacturing process for HDPE fuel tanks typically involves rotational molding or blow molding. In rotational molding, a heated mold is used to melt the plastic, which then forms a puddle at the bottom of the mold cavity. The mold is slowly rotated, causing the melted plastic to flow into the desired shape. This process results in a seamless one-piece construction that typically consists of at least six layers of different materials, each providing unique beneficial characteristics.
One example of a multilayer HDPE fuel tank is the six-layer design used by Ford, which consists of an inner layer of HDPE, an adhesive layer, a barrier layer of polyamide or ethylene-vinyl alcohol copolymer, another adhesive layer, a layer of "regrind," and an outer layer of HDPE. This multilayer construction helps to meet stricter emission standards and improve fuel efficiency.
While HDPE has been a popular choice for plastic fuel tanks, there have been some concerns about its performance. For instance, in the 1990s, small gas tanks made with HDPE were found to crack due to a failure to understand the interaction between molecular weight and density. However, this issue was eventually resolved by developing a grade of HDPE with a lower density.
When deciding between a steel fuel tank and a polyethylene (HDPE) fuel tank, it is important to consider the specific requirements and cost-effectiveness of each option. Both materials have their advantages and disadvantages, and in some cases, a combination of the two may be the best solution.
Hydrogen Fuel Tanks: Production and Energy Storage
You may want to see also
Explore related products
Polypropylene (PP) is another material used
Polypropylene is an inexpensive polymer with a wide variety of uses. It is a linear hydrocarbon with little or no unsaturation, resembling polyethylene. However, the -CH3 groups cause stiffening and less stability with regard to oxidation. The properties of polypropylene depend on the molecular weight and molecular weight distribution, crystallinity, type and proportion of comonomer, and isotacticity.
The methyl group improves mechanical properties and thermal resistance, although chemical resistance decreases. Commercial polypropylene is usually isotactic, which means the methyl groups are oriented on one side of the carbon backbone. This creates a greater degree of crystallinity and results in a stiffer material that is more resistant to creep than atactic polypropylene and polyethylene. The density of PP is between 0.895 and 0.93 g/cm3, making it the commodity plastic with the lowest density.
There are three general types of polypropylene: homopolymer, random copolymer, and block copolymer. The melt flow rate (MFR) or melt flow index (MFI) is a measure of the molecular weight of polypropylene and helps determine how easily the molten raw material will flow during processing. A higher MFR will fill the plastic mold more easily, but some physical properties, like impact strength, will decrease.
Creating Plastic Fuel Tanks: A Step-by-Step Guide
You may want to see also
Explore related products
Regrind plastic is recycled polyethylene
Plastic fuel tanks are typically made from five different materials: high-density polyethylene (HDPE), polypropylene (PP), regrind plastic (recycled polyethylene), a plastic adhesive, or ethyl vinyl alcohol (EVOH). Regrind plastic, also known as recycled polyethylene, is an essential component of these fuel tanks and offers a sustainable solution by minimising plastic waste.
Regrind plastic is produced by reclaiming and repurposing excess material and rejected parts from previous projects. This process allows for the reduction of waste and the optimisation of resources. However, it is crucial to address certain challenges associated with the use of regrind plastic. One of the primary concerns is contamination, which can result from improper material handling. To prevent this, specific material handling procedures must be established, including proper cleaning of grinders and hoppers and ensuring that material containers remain covered.
Another critical aspect of utilising regrind plastic is managing its heat history. When thermoplastic is exposed to thermal and mechanical stress, it can become weak and brittle, leading to degradation in its physical, chemical, and flow properties. Therefore, maintaining an optimal temperature during the regrinding process is essential to preserving the quality of the regrind plastic.
Furthermore, regrind plastic must be strategically blended with new resin to ensure optimal performance. The regrind ratio and the number of regrind passes can impact the physical properties of the final product. It is recommended to consult with resin suppliers to understand the limitations of their products and to implement proper drying procedures for resins to prevent hydrolysis and subsequent degradation.
By addressing the challenges associated with regrind plastic and implementing proper procedures, the plastic industry can effectively reduce waste and costs. Regrind plastic plays a significant role in the production of plastic fuel tanks, contributing to sustainability and resource efficiency while ensuring the safe storage and transportation of flammable substances.
Backpacking Stove Fuel Tanks: Buying Guide
You may want to see also
Explore related products
Plastic adhesives are used in the construction of plastic fuel tanks
Plastic fuel tanks are typically made from several layers of different materials, providing distinct beneficial characteristics. One of the critical components used in their construction is plastic adhesives, which play a vital role in ensuring the tank's integrity and functionality.
Plastic adhesives are specialized substances designed to bond plastic surfaces together securely. In the context of fuel tanks, these adhesives serve multiple purposes. Firstly, they act as a crucial barrier layer within the tank's multilayer structure. This barrier layer is essential for preventing the permeation of hydrocarbons, such as gasoline or fuel, through the tank walls. By using adhesives with low hydrocarbon permeation rates, the fuel tank can effectively contain flammable substances without leakage.
Additionally, plastic adhesives contribute to the overall strength and durability of the fuel tank. During the construction process, adhesives are applied between the layers of the tank, essentially "gluing" them together. This bonding process creates a seamless, one-piece construction that enhances the structural integrity of the tank. As a result, the fuel tank can withstand mechanical stresses and impacts without compromising its integrity.
The use of plastic adhesives in fuel tank construction also offers flexibility in terms of repair and maintenance. Should the tank develop cracks or leaks, plastic-compatible adhesives can be employed to seal and repair the damaged areas. For example, products like TechBond, epoxy, and reinforced fibreglass epoxy have been successfully used to repair fuel tanks, restoring their functionality and preventing fuel leakage.
In summary, plastic adhesives are an indispensable component in the construction of plastic fuel tanks. They provide a vital barrier against hydrocarbon permeation, enhance the tank's structural integrity, and facilitate effective repair solutions. By utilizing plastic adhesives, manufacturers can create safe and durable fuel storage solutions that meet stringent emission and safety standards.
Fuel Storage: How Long Does Gas Last?
You may want to see also
Explore related products
Ethyl vinyl alcohol (EVOH) is also used
Plastic fuel tanks, also known as polyethylene tanks, are typically made from high-density polyethylene (HDPE). However, they can also consist of several layers of different materials, each providing unique benefits. Ethyl vinyl alcohol (EVOH) is one such material that is often used in combination with HDPE and other substances to enhance the performance of plastic fuel tanks.
EVOH is an essential component in multilayer fuel tank technology, which some manufacturers adopt to meet stricter emission standards and improve fuel tank safety. When used in multilayer fuel tanks, EVOH acts as a barrier layer, reducing the permeation of hydrocarbons and other flammable substances. This barrier property is crucial for preventing fuel leakage and minimizing the risk of accidents.
The use of EVOH in fuel tanks is particularly notable in the automotive industry. For instance, Ford considered investing in machinery to produce multilayer fuel tanks with EVOH to comply with California's stringent evaporative fuel standards. While Ford ultimately switched back to steel tanks, other automotive manufacturers, such as Chrysler, have utilized HDPE tanks with EVOH barriers to increase volume capacity and meet emission requirements.
The effectiveness of EVOH in fuel tanks has been demonstrated through various studies and field tests. For example, Solvay Automotive developed technology that combines Solvay-optimized fluorination with EVOH barrier resin. This technology has been successful in reducing emissions in methanol-containing fuels, showcasing the ability of EVOH to enhance the performance of plastic fuel tanks and meet evolving industry standards.
In summary, ethyl vinyl alcohol (EVOH) is a vital material in the construction of plastic fuel tanks, particularly when combined with other substances in multilayer designs. Its barrier properties significantly reduce hydrocarbon permeation, enhancing the safety and environmental performance of fuel storage systems. As emission standards become more stringent, the role of EVOH in fuel tank technology is likely to continue evolving, driving innovations in the automotive and fuel storage industries.
Stripping Paint from Your Motorcycle Fuel Tank: A Step-by-Step Guide
You may want to see also
Frequently asked questions
Plastic fuel tanks are made from a variety of materials, including high-density polyethylene (HDPE), polypropylene (PP), regrind plastic (recycled polyethylene), plastic adhesive, and ethyl vinyl alcohol (EVOH).
Plastic fuel tanks are lighter, cleaner, and more flexible than steel tanks. They are also more cost-effective and have a longer lifespan. Additionally, plastic fuel tanks can provide safe storage and transportation of flammable substances.
One disadvantage of plastic fuel tanks is that they are more susceptible to weakness in the walls compared to steel tanks. Additionally, polyethylene fuel tanks can absorb 7-8% of their weight in gasoline, which can result in a significant decrease in strength and modulus.
