Air Shower, is one of the common and crucial devices in cleanroom systems. So, what exactly is an Air Shower? How is it structured, and what are its operating principles? What should be considered for its durable use? Let’s find out with INTECH Service in the following article!
What is an Air Shower?
An Air Shower, also known as an air blowing chamber or air bath, is a device used to minimize cross-contamination between areas with different cleanroom levels in factories, laboratories, and other environments requiring high cleanliness control.
They are often installed between cleanrooms and non-cleanrooms, between cleanrooms and external areas, or between cleanrooms with different cleanliness levels.
Structure of an Air Shower
The structure of an Air Shower may vary depending on the manufacturer and usage requirements. However, typically an Air Shower will include the following basic components: Body section; Central control unit; Centrifugal fan; Filter unit; Air nozzles; Door; and some other components.
Body section: Includes inner and outer bodies. The inner body is usually made of 304 stainless steel to ensure cleanroom standards. The outer body can be made of 201 stainless steel, electrostatically painted steel, or galvanized steel.
Central control unit: Controls the operation of the Air Shower. It can set operating time, air velocity, and other functions.
Centrifugal fan: Helps generate airflow and is responsible for air blowing. The fan power depends on the size and requirements of each type of Air Shower.
Filter unit: Uses HEPA or ULPA filters, typically H13, to filter out 99.99% of dust particles larger than 0.3μm. The filter unit helps produce clean air to blow away dirt on surfaces.
Air nozzles: Located inside the Air Shower, the exit of the air stream. Air from the air nozzles will blow onto objects and people. There are two main types: spray nozzles and blow slits.
Door: The door usually integrates features for motion control to regulate opening and closing. When one door opens, the remaining doors must close to ensure the effectiveness of the Air Shower operation.
Spray nozzles: Depending on the design, the Air Shower may have additional spray nozzles to spray water or disinfectant solution.
Other components: In addition to the above components, the Air Shower may be equipped with additional signaling light systems, alarm systems, and PLC control systems.
Operating Principles of an Air Shower
The operating principle of an Air Shower is quite simple, as follows: when moving goods from the outside and when personnel move through the Air Shower, immediately the system of spray nozzles installed on the walls in the room is activated (thanks to motion sensors).
Continuing this process, the system is started, simultaneously clean air will flow from the coarse filter through the HEPA filter and the static pressure box. They are blown through the spray nozzles with high power to remove dirt and dust on the human body or on goods, materials.
After completing the air blowing process, the rear door opens for employees and goods to move into the cleanroom to work.
Then, the airflow will be recirculated back through the cabinet foot slot into the coarse filter. This process is repeated multiple times, circulating back to the Air Shower chamber.
Classification of Air Showers
Tunnel-Type Air Shower
This type has a structure similar to a tunnel, with a length greater than other types of Air Showers.
People or objects entering the air shower will move through the airflow from top to bottom to remove dirt.
Advantages:
High dust filtering efficiency.
Can be used for multiple people or objects at the same time.
Disadvantages:
Large size, occupying a lot of space.
High cost.
Single-Door Air Shower – Rotating Door
This type has one door, designed to rotate 90 degrees when opening and closing.
People or objects will enter the air shower through the rotating door, then the door will automatically close and the fan will operate.
When the air blowing process ends, the door will automatically open for people or objects to exit.
Advantages:
Compact size, space-saving.
Reasonable cost.
Disadvantages:
Lower dust filtering efficiency compared to tunnel-type Air Shower.
Only suitable for one person or object at a time.
Roll-up Door Air Shower
This type has a roll-up door, designed to roll up when opening and roll down when closing, suitable for areas requiring high cleanliness, due to the fast opening and closing speed, preventing heat loss.
Advantages:
High dust filtering efficiency.
Space-saving when opening the door.
Disadvantages:
High cost.
Complex structure, requiring regular maintenance.
Two-Door Sliding Air Shower
This type has two doors, designed to slide to both sides when opening and closing.
This type of Air Shower is suitable for large spaces, large numbers of workers, and high traffic density. Especially suitable for spaces with many trolleys passing through.
Advantages:
Space-saving compared to rotating door type.
Easy to use.
Disadvantages:
Higher cost compared to the rotating door type.
More complex structure, requiring regular maintenance.
Two-Door Rotating Air Shower
This type has two doors, designed to rotate 90 degrees when opening and closing, suitable for large spaces, large numbers of production workers, and high traffic density.
Advantages:
High dust filtering efficiency.
Can be used for multiple people or objects at the same time.
Disadvantages:
Large size, occupying a lot of space.
High cost.
Considerations for Durable Air Shower Usage
Pay attention to the temperature when using; the operating temperature of the device should not exceed 50 degrees Celsius. Therefore, you need to install a thermal relay in the Air Shower to automatically open and close in case of overheating.
Regularly check to determine the technical specifications of the equipment, such as air flow, air blowing speed, filtration efficiency, power consumption, etc…. In case the technical specifications are not met, timely handling is required.
Regularly maintain the door to ensure that the electronic lock is aligned with the keyhole to prevent the door from jamming.
If you feel that the air velocity is gradually decreasing, first check if the air filter surface is dusty. If it is black, it means that the filter housing has too much dust and a large clogged area, leading to poor ventilation. It is necessary to remove the filter unit for replacement or cleaning.
When the fine filter is replaced or cleaned and the air velocity cannot reach normal levels, it means that the HEPA filter is clogged, resulting in slow air velocity. In this case, the HEPA filter needs to be replaced.
Adhering to the disassembly instructions during Air Shower usage is also a way to increase the lifespan of the equipment. Some disassembly instructions are as follows: before replacing the HEPA filter, you need to remove the spray nozzle panel and then take out the filter unit. Also, the HEPA Filter (installed in the Hepa box) to be replaced must have the same shape and specifications as the original. When installing, follow the arrow marks on the filter. This arrow indicates the direction of the air flow.
Regularly check the electrical circuit of the Air Shower to increase the lifespan of the equipment. In case of detecting faults, you can repair them according to the electrical diagram.
Regular maintenance of the Air Shower to increase the lifespan of the product.
When to Replace Air Shower Filters?
Filters play an important role in ensuring the efficiency of Air Shower operation. When operating for a long time, they can accumulate dust, become damaged, so they need to be regularly checked, cleaned, and replaced to ensure the best operation of the Air Shower.
Signs indicating the need to replace Air Shower filters:
Decreased air flow: Reduced cleaning efficiency and a feeling of stuffiness when using the Air Shower.
Increased noise: Louder than normal noise indicates that the filter is dirty and needs to be replaced.
Decreased air filtration efficiency: Odors, dust, and pollutants appear in the area after using the Air Shower.
Recommended replacement times for Air Shower filters:
Pre-filter removes large dust particles, insects, and other impurities. It should be replaced every 3 months.
HEPA filter removes small dust particles (sized from 0.3 microns and above), bacteria, viruses, and other pollutants. It should be replaced every year.
The above are the information about the structure, operating principles, and considerations for durable Air Shower usage. INTECH Service is an experienced company in the field of cleanroom system maintenance, HVAC. If you have any questions or need advice, please contact us immediately to receive consultation from our engineers and experts.