The Complete Guide to Tank Fabrication

Plastic Design Inc. Tank LinesTank fabrication is the production process from designing large industrial tanks through assembling the tanks and their associated hardware or accessories. Tank fabrication can incorporate an extensive variety of design software, specifications, materials, production methods, and testing procedures, and each manufacturer specializes in distinct methodologies. For example, some manufacturers focus on traditional carbon or stainless steel tanks. Others specialize in plastic tank production because of the material’s nascent capabilities in different industries. At Plastic Design, Inc., we specialize in custom plastic tank fabrication.

 

Plastic Welding

Because plastic materials are easy to work with, manufacturers can produce plastic tanks through a range of different methods. One of the most common is plastic welding. Much like traditional welding, this process uses heat to create a molecular bond between two compatible thermoplastics. Plastic welding has three stages—pressing, heating, and cooling.
Manufacturers use a welding tool to create lines or spots of heated, melting plastic and then overlay another plastic sheet on top of the melted points. When the plastic cools and rehardens, it creates a strong, durable bond that can be used in products across a range of industries, such as dairy, food packaging, papermaking, and chemical. There are several different methods of this process, including ultrasonic, laser, vibration, spin, hot plate, and infrared welding.

Plastic welding reduces cycle times and provides superior strength. The finished plastic welds are lightweight and offer an airtight seal to prevent any leaks. Manufacturers commonly use it to conjoin plastic sheets when an adhesive binding is insufficient or unadvisable.

Other popular methods for tank fabrication include compounding (or blending), plastic lamination, molding processes, plastic extrusion, and plastic foaming.

Plastic Tank Applications

Plastic tanks are resistant to chemical and water damage. They can also handle heavy loads without forming stress cracks or being vulnerable to physical damage. These characteristics make plastic tanks ideal for sensitive industrial applications, such as in the biomedical, pharmaceutical, and semiconductor industries.

Biomedical and Pharmaceutical

These industries use a wide variety of chemicals to conduct tests and produce complex compounds and goods. Many of the base materials need to be stored for long periods of time in concentrated doses. Plastic tanks can handle alkaline and acidic chemicals and chemical compounds without degrading. The material is chemically inert, so manufacturers can worry less about the risk of degradation or contaminants from the tank material mixing into the chemicals. Plastic Design, Inc. produces plastic tank systems that range from single-use to USP Class 6 certification, so biomedical and pharmaceutical companies can safely use the tanks while remaining compliant with good manufacturing practices.

Semiconductor Manufacturing

Semiconductor manufacturing processes involve a lot of heat, caustic chemicals, and pressurized materials. Plastic tanks can withstand high temperatures and pressures without breaking down. The smooth and chemically inert surfaces of the tanks also ensure that the chemicals won’t break down the tanks or leech molecules from the tank and into the base material. Our chemical storage tanks and acid drums are safe, easy to clean, and reliable. Manufacturers can use them anywhere from general chemical storage sites to cleanrooms.

Materials Used in Plastic Tank Fabrication

At Plastic Design, Inc., we use three primary plastic polymers to create our tanks. These three materials are PVC, PVDF, and Polypropylene.

PVC

Polyvinyl chloride, or PVC, comes in different flexibility and rigidity levels based on the amount of plasticizers added to the compound. The material offers a low degree of flammability, resistance to corrosion, and resistance to chemical damage. However, the tensile strength of the plastic can vary depending on the level of plasticization.

PVDF

PVDF is a fluorocarbon with piezo-electric properties that operates best at lower temperatures that remain below 150°C. The material resists damage from abrasion, radiation, and chemicals. It’s also strong and easy to work with through melting processes. However, the material can’t incorporate glass fibers, is vulnerable to damage from fuming acids, and has a high dissipation factor.

Polypropylene

This polymer also works best at lower temperatures, though its range is greater than many other plastics because of its heat deflection properties. It has a high degree of tensile strength, and its semi-crystalline structure helps make it very resistant to chemical damage. However, it has elongation at break and a lower notched strength than other plastics. When it’s overheated, the material can become brittle.

Types of Tanks Provided

We design, fabricate, and finish many different types of tanks to suit different industries’ manufacturing processes, such as:

  • Custom Plastic Tanks: We can produce tanks with different dimensions, including size, shape, and wall thickness.
  • Custom Holding Tanks: Just like our custom plastic tanks, these can have virtually any specifications. Our design process also takes into account the weight stress of long-term chemical storage and weight distribution solutions.
  • Custom Fabricated Day Tanks: We outfit all of our biomedical and pharmaceutical tanks with the tools for long-term chemical storage. Each tank features heavy walls and high load extrusion welding to reduce the risk of failure or contamination.
  • Batch Mixing Tanks: These tanks can be customized to include auto-fill systems, closed-loop filtration, angled vanes for better mixing, and more. We can also build them to meet almost any design specifications. Our batch mixing tanks can handle shear mixing processes without including excess air.
  • Double Containment Tanks: If your facility handles hazardous materials that are under pressure, our double containment tanks can help. They meet strict containment standards and failsafe mechanisms to keep the contents sealed away from the environment and nearby workers. The accessories for these tanks, such as plumbing, also meet strict standards, and the tanks can be outfitted with online leak detection systems.
  • Custom Plating Tanks: These tanks enable recirculation and filtration. Our tanks include temperature controls and DC power supplies.
  • Custom Closed Loop Filtration: These tank systems are built to handle your facility’s preferred pumping methods, such as high-volume centrifugal and positive displacement systems.
  • Custom Fabricated Temperature Controlled Process Tanks: These tanks can handle wide temperature ranges, and we can fabricate either plastic or stainless steel varieties to handle both low and high-temperature operations or environments.

Choose Fabricated Tanks From Plastic Design, Inc.

At Plastic Design, Inc., we work hard to design and produce custom tanks that meet the needs of each of our customers. We’re an ISO 9001:2015 certified company. Our other certifications include Factory Mutual, Semi, NFPA, and OSHA. Learn more about our plastic tank design capabilities to see if we’re an excellent fit for your next project. You can also request a quote or specify your tank design requirements to get started.

Choosing a Material for Plastic Chemical Tanks

Plastic chemical tanks are used for holding and storing harsh and corrosive chemicals in a variety of applications across many industries. Plastics are versatile, inexpensive to manufacture, and chemically adaptable—properties that have led to the replacement of expensive stainless steel tanks throughout manufacturing processes for biomedical, pharmaceutical, and semiconductor industries. Because some plastics can react with different chemicals, heat, or pressure, tanks must be designed using materials specifically tailored for the chemicals and processes they need to hold.

Industries for Plastic Chemical Tanks

Biomedical and Pharmaceutical

You will often find plastic chemical tanks used in the biomedical and pharmaceutical industries, where they are employed to store, drain, and mix chemical compounds. The tanks need to be composed of materials that will not interact with or leach into the compounds they are holding. Tanks for pharmaceutical and biomedical use are often constructed using rigorously tested USP Class VI Certified plastics to ensure biocompatibility and prevent toxic interactions with the chemicals in use.

Semiconductor

Plastic chemical tanks used in the semiconductor industry must be highly resistant to corrosion and safe for sterile use in clean rooms. They are useful in harsh environments for the manufacture of circuitry and electronic components for semiconductor equipment. The tanks must be constructed of durable and highly inert plastics to withstand the hot gas, aggressive chemicals, and high-pressure used in the industry, as well as avoid corrosion and a reaction with the materials being used.

Common Materials Used in Plastic Tanks

Depending on their intended use, plastic tanks must be carefully constructed to tolerate various volatile circumstances without risk of corrosion or leaching. As such, a number of different plastic materials are used in their construction.

  • Polypropylene is a versatile semi-crystalline material that is highly chemically resistant at low temperatures, but can be less stable at very high temperatures.
  • Polyvinylidene difluoride, or PVDF, is a strong fluropolymer that has high chemical resistance, but is less stable at high temperatures.
  • High Density Polyethylene, or HDPE, is an opaque semi-crystalline thermoplastic that is highly chemical resistant and impact resistant at low temperatures.
  • PVC, or polyvinyl chloride, comes in both rigid and flexible varieties. It is highly resistant to corrosion and has fair to good chemical resistance.

Properties of Each Material

Each plastic material has physical and chemical properties that help determine which is best for a given chemical or application. When choosing a material, consider the tensile strength, dielectric strength, and maximum operating temperature of each material to ensure that the ideal material is being used in each circumstance. Below is a short list of the important physical properties of each of the plastics commonly used in plastic tanks:

Polypropylene

  • Tensile Strength (MPa): 33
  • Dielectric Strength (MV/m): 28
  • Maximum Operating Temperature: (°C): 100

PVDF

  • Tensile Strength: 35
  • Dielectric Strength (MV/m): 13
  • Maximum Operating Temperature: (°C): 150

HDPE

  • Tensile Strength (MPa): 32
  • Dielectric Strength (MV/m): 22
  • Maximum Operating Temperature: 55

PVC

  • Tensile Strength (MPa): 20
  • Dielectric Strength (MV/m): 30
  • Maximum Operating Temperature: (°C): 50

Advantages and Disadvantages of Plastic Materials

Plastic Material Advantages Disadvantages
Polypropylene
  • Higher maximum operating temperature (100°C /210°F)
  • Better tensile strength than unmodified polypropylene copolymer
  • Higher heat deflection temperature (HDT) than unmodified polypropylene copolymer
  • Lower notched impact strength
  • Elongation at break
  • Higher brittle temperature (0°C/30°F) than unmodified polypropylene copolymer
PVDF
  • Highest tensile strength of all processable fluorocarbons
  • Good radiation resistance (better than other fluorocarbons)
  • Melt processable
  • Excellent abrasion resistance
  • Good general chemical resistance, although inferior to PTFE
  • Maximum use temperature 150°C (300°F)
  • Useful piezo-electric properties
  • High dissipation factor
  • Processing machinery must be clean and free of debris
  • Cannot blend with glass fibers, as boron will cause the material to decompose
  • Poor resistance to fuming acids
HDPE
  • Good low-temperature impact resistance
  • Excellent chemical resistance
  • Susceptible to stress cracking
  • Lower stiffness compared to Polypropylene
  • High mold shrinkage
  • Poor UV resistance
PVC
  • Higher tensile strength than PVC with higher levels of plasticization
  • Less flammable than PVC with higher levels of plasticization
  • Lower elongation at break than PVC with higher levels of plasticization
  • Lower low-temperature impact strength than PVC with higher levels of plasticization

Contact Plastic Design for Plastic Chemical Tanks

Plastic Design Inc. is proud to offer high-quality custom plastic tank designs using precise processes and procedures that are fully ISO 9001:2015 certified. We can manufacture products in high quantities that meet and exceed industry specifications, including Factory Mutual, Semi, NFPA, and OSHA. Our knowledgeable and experienced engineers are available to conduct on-site surveys and evaluations of your existing systems, so you can find the best solutions and modifications for your needs.

For more information on our custom plastic tank services and pricing, contact us or request a quote today!