Compressed air buffer tank

Types of Compressed Air Buffer Tanks

A compressed air buffer tank is a container that stores air under pressure. There are two common types of compressed air tanks: vertical tanks and horizontal tanks.

• Vertical Compressed Air Tanks

  Vertical compressed air buffer tanks generally have a tall and cylindrical shape. They take up little floor space and can be installed on the floor or hung on the wall. This type of buffer tank is ideal for commercial and industrial establishments with limited ground space to install equipment. The vertical design makes it convenient to mount on the wall or, in some cases, on the ceiling, freeing up valuable floor space for other uses. Despite its small footprint, this configuration provides sufficient storage capacity for compressed air. It meets the demands of various applications while optimizing the use of limited indoor space. Vertical compressed air tanks can be mounted on the wall or the ceiling, which is an excellent choice for places with a small area.

• Horizontal Compressed Air Tanks

  Horizontal compressed air buffer tanks are designed with a cylindrical or rectangular shape. It requires more ground space than vertical compressed air tanks. Nevertheless, the horizontal tank is much easier to install and maintain. The horizontal compressed air tank provides stable support. It is usually used in places where the floor space is adequate, such as factories, warehouses, and workshops.

Specifications and Maintenance of Compressed Air Buffer Tanks

Specifications

• Sizes: The size of the air tank is determined by its diameter and height (or length). Commonly used air tank sizes include 30-liter, 50-liter, 90-liter, 150-liter, 270-liter, etc.
• Maximum operating pressure: This refers to the maximum design pressure that the tank can withstand. For most buffer tanks, the maximum operating pressure is 1.0Mpa (approximately 145psi), 1.6Mpa (approximately 232psi), or 2.5Mpa (approximately 362psi).
• Connection methods and sizes: Buffer tanks usually have some connecting devices to connect the tanks to air compressors or tools. These connection methods and sizes are specified to ensure a proper fit and seal between the components.
• Materials: Compressed air buffer tanks commonly use metal materials such as carbon steel or stainless steel. Carbon steel has excellent strength and durability, making it suitable for manufacturing buffer tanks. Stainless steel possesses high corrosion resistance, allowing it to withstand harsh environments and remain functional over the long term.
• Coatings: The inner and outer surfaces of the compressed air buffer tank are coated with protective coatings. The protective coating on the outside of the tank can prevent corrosion and rust, while the protective coating on the inside can protect the tank from the harmful effects of moisture or impurities in the compressed air.

Maintenance

• Regular inspection: Regularly inspect the surface and connections of the compressed air buffer tank for signs of damage, such as cracks, leaks, etc. If any issues are found, timeliness is necessary for repairs.
• Clean: Periodically clean the inner and outer surfaces of the air buffer tank. Use suitable detergents to wipe the surfaces of the tank, removing dirt, oil, and dust.
• Check components: Check the components related to the air buffer tank, such as pressure relief valves, drain valves, etc. Ensure they are operating correctly, which helps maintain the performance and safety of the tank.
• Remove moisture: Compressed air contains water vapor. Therefore, it's essential to periodically drain the moisture from the air buffer tank using the drain valve, thus preventing corrosion and mold growth inside the tank.
• Pay attention to air quality: The quality of the compressed air affects the state of the air buffer tank. Therefore, installing air filters and drying equipment before the tank is recommended to remove impurities and moisture from the air.
• Prevent overpressure: Compressed air buffer tanks are designed for specific pressure limits. Avoid over-pressurizing the tank during use, as this may cause damage or safety hazards.

Scenarios

Compressed air buffer tanks are used in various industries where the main air compressor is connected to a piping network supplying compressed air. The following are scenarios in which a compressed air buffer tank may be utilized.

• Increase system pressure

  A compressed air system in a factory may have multiple machines that require compressed air to function. In certain situations, the machines may require more compressed air than what the compressor can supply. A buffer tank can be used to store additional compressed air. This additional air will be available to machines when needed, thereby preventing a drop in system pressure and maintaining compressed air delivery.

• Reduce compressor on/off cycling

  A compressor with no buffer tank will supply compressed air on demand. This scenario will make the compressor turn on and off frequently, thereby causing wear and tear. If a buffer tank is installed, the compressor will supply compressed air to the tank. The tank will release compressed air on demand. The tank will be able to meet low air demand. Therefore, the compressor will not turn on frequently. The on and off cycling of the compressor will be reduced.

• Cooling of compressed air

  A buffer tank can be used to cool down hot compressed air. This situation may happen when a compressor does not have an aftercooler or inline aftercooling drying system. The hot compressed air in the buffer tank will transfer its heat to the tank walls. When the heat is transferred, the air will cool. If the compressed air needs to be dried, a drying agent could be put in the tank to absorb moisture from the compressed air.

• Storing excess compressed air

  A compressed air system may be producing more compressed air than it needs. This excess compressed air can be stored in a buffer tank and be used when required. It can also be used to achieve more rapid machine cycling operations and peak demand periods.

How to choose a compressed air buffer tank

• Assess air demand:

  Estimate average daily operational demand. Consider the number of tools and their usage per shift. Analyze peak vs. constant demand. Buffer tanks can handle short peak periods by smoothing air supply over time.

• Match tank size to demand:

  Calculate the amount of stored air needed using: Storage Volume (cubic feet) = Area Under Curve (cubic feet) / 60-minutes. Area under Curve, calculate the difference between compressor output and tool input over time. A detailed analysis is required to determine the volume.

  A rough guide is to store 10 gallons per 1 cfm of constant demand. 30 minutes of tool operation is possible with 30 minutes of air storage when tools are not used continuously.

• Select tank location:

  Tanks can be located near the air compressors to reduce long piping runs or close to air tools for reduced piping pressure loss. Determine the most cost-effective and convenient location based on air distribution requirements.

• Consider tank type:

  Decide if a vertical or horizontal tank is preferred based on available space and budget. Horizontal tanks are typically lower cost but take up more floor space. Vertical tanks are more compact but higher cost.

• Assess additional equipment:

  Drum filters, refrigerated dryers, auto drains, and pressure regulators improve air quality but add to system cost. Determine which accessories are needed based on tool sensitivity and air quality required.

Q&A

Q1 How big should a compressed air buffer tank be?

A1 The size of the air tank generally depends on the volume flow rate of the air compressor. This is usually measured in CFM or cubic foot per minute. For applications that require a constant air supply with minimal interruptions, a tank with a capacity of around 60 to 80 gallons is recommended. However, the ideal size can be determined by using a 10 percent rule. Calculate the actual CFM generated by the application and then increase the value by 10 percent. This value is the ideal compressed air buffer tank.

Q2 What is the difference between a receiver and a tank buffer?

A2 A receiver buffer is primarily used to temporarily store compressed air before it is released into the system. A receiver also helps to separate moisture from the compressed air and pressure fluctuations. On the other hand, a tank buffer is used to store compressed air longer, usually for hours or days. The tank buffers also regulate system pressure.

Q3 Can someone add a buffer tank to an existing compressed air system?

A3 Yes, it is possible to add a compressed air buffer tank to an existing air compression system. Sizing and proper placement of the new tank is essential for optimal performance. Working with a qualified engineer or system technician to ensure a seamless integration is important.

Q4 What are some signs that a compressed air system needs a buffer tank?

A4 Frequent pressure drops throughout the system during peak usage periods are strong signs that additional buffer tanks are required. Other signs include compressors cycling on and off frequently, high humidity and moisture levels in the compressed air, inconsistent air pressure in fixed systems, and compressors being overloaded during peak usage times.