Comparing Dish-Bottom, Flat-Bottom and Cone-Bottom Tanks

The ideal tank design depends on factors such as the type of material being processed and the required tank capacity. However, the first question is – what type of steel tank is best for your project? 

When choosing a stainless steel tank for your application, it’s important to understand the key differences between flat-bottom, dish-bottom, and cone-bottom tanks to make an informed decision.

Each design offers distinct advantages for mixing or storing ingredients, and customizing the tank to meet your specific project needs is essential for optimal performance.

What are Flat-Bottom Tanks & Their Uses?

Flat-bottom tanks are designed with a flat surface at the base, which makes them easy to place on solid, flat foundations. These tanks are commonly used for bulk liquid storage because their simple design allows for maximum volume capacity. Although a cost-effective option for storage, flat-bottom tanks are not ideal for mixing or processing.

Typically flat-bottom tanks are a standard design made from stainless steel or carbon steel materials for longevity. This makes them a popular choice for several industries and uses.

Common Applications of Flat-Bottom Tanks

• Large-scale water storage
• Chemical and fuel storage
• Industrial process tanks
• Agricultural storage for liquids such as fertilizers and pesticides
• Storage tanks for wastewater treatment
  
  

Disadvantages of Flat-Bottom Tanks

One of the main drawbacks of flat-bottom tanks is that they tend to create areas of stagnation, particularly around the edges where the tank wall meets the floor. Without additional flow-inducing mechanisms, such as well-placed agitators or flow baffles, these areas can cause incomplete mixing, leading to product inconsistencies. 

The flat surface also limits natural circulation and makes it harder to achieve an even mix across the entire volume, particularly for viscous fluids or when thorough blending is essential.

What are Dish-Bottom Tanks & Their Uses?

Dish-bottom tanks have a curved base, making them ideal for draining liquids and minimizing sediment buildup. Similar to flat-bottom tanks, dish-bottom tanks are often custom-designed and constructed from durable materials like stainless steel to promote integrity and quality.

Common Applications of Dish-Bottom Tanks

• Food and beverage production, especially for liquids prone to sediment buildup
• Pharmaceutical and chemical processing
• Brewery and winery fermentation tanks
• Wastewater and slurry storage
  
  

Downfalls of Dish-Bottom Tanks

While dish-bottom tanks offer improved drainage over flat-bottom designs, they come with certain drawbacks. One key disadvantage is the potential for product accumulation at the transition point between the tank wall and the dished bottom, which may hinder complete drainage without proper design considerations. This can lead to residue buildup, particularly in highly viscous products, increasing the need for frequent cleaning and maintenance.

Additionally, dish-bottom tanks may not be as cost-effective as flat-bottom designs, as they require more complex fabrication and specialized accessories, such as drain ports or bottom outlets, to ensure effective product discharge and cleaning.

What are Cone-Bottom Tanks & Their Uses?

Cone-bottom tanks have a conical base to drain liquids and prevent sediment – similar to dish-bottom tanks. The conical shape makes these tanks easy to clean and allows easy access for mixers to stir and blend materials inside. 

Typically, cone-bottom tanks are made from high-quality materials, such as stainless steel, and custom-designed – similar to flat-bottom and dish-bottom mixers. 

Common Applications of Cone-Bottom Tanks

• Chemical and pharmaceutical production
• Agricultural liquid storage
• Industrial mixing and blending processes
• Fermentation and brewing industries 
  
  

Disadvantages of Cone-Bottom Tanks

While cone-bottom tanks provide excellent drainage, they come with higher costs due to more complex fabrication and the need for support structures like stands. Additionally, the conical shape can lead to uneven mixing, especially with viscous fluids, as material may settle at the bottom without proper agitation, potentially affecting product consistency.

Key Factors When Choosing a Stainless Steel Tank Design

Stainless steel tanks aren’t one-size-fits-all, and a custom design ensures the tank meets the specific needs of your application. Whether you need a flat-bottom, dish-bottom, or cone-bottom tank, understanding the key design factors will help to optimize performance, durability, and safety in your operations. 

Here are the most important factors to consider when customizing a stainless steel tank: 

Tank Capacity 

Understanding the volume of liquid you’ll be storing or processing is necessary to determine the size and dimension of the tank. When customizing your tank, both the vertical height and diameter can be adjusted based on your space constraints and volume needs.

Material Grade 

Typically, tanks are created from stainless steel since it’s a durable material choice. The type of stainless steel varies depending on the tank use. If you’re storing corrosive or reactive substances, like chemicals, it’s important to choose a high-quality material.

Common stainless steel grades include 304 and 316 stainless steel – with 316 offering higher corrosion resistance.

Tank Wall Thickness

The thickness of the tank’s walls should match the pressure, weight, and types of liquids the tank will hold. High-pressure applications, such as those involving gases or chemicals, often require thicker walls to prevent ruptures or leaks. 

Additionally, thicker walls offer more durability for tanks exposed to extreme environmental conditions.

Tank Insulation and Jacket Design

If the application involves temperature-sensitive products, it is important to address the need for thermal insulation or jacketed designs. Tanks may require maintaining a precise temperature during both processing and storage. 

To achieve this, incorporating insulating materials can minimize heat loss or gain, while steam or cooling jackets can help regulate temperatures effectively, ensuring product stability throughout the process.

Getting Started with Dish-Bottom, Cone-Bottom, or Flat-Bottom Tanks

Understanding the differences between flat-bottom, dish-bottom, and cone-bottom tanks is essential to making an informed decision on which stainless steel tank is best for your application.

Additionally, these stainless steel tanks should be customized to meet your project’s needs, keeping factors like the type of material stored and tank capacity in mind. If you’re ready to design your tank and need guidance, explore our custom tank designer or contact the MXD Process team!