A clean bench is an enclosed workbench designed to prevent airborne contaminants, such as dust and dirt, from adhering to the materials being handled. Clean air, passed through a high-performance HEPA filter, flows directly over the workspace to maintain a high level of cleanliness (ISO Class 5 or higher) even in uncontrolled environments. These systems are essential in factories, laboratories, and research facilities requiring contamination-free workspaces.
While similar in appearance to "safety cabinets" (biosafety cabinets), the primary distinction lies in the airflow design and protection target. Safety cabinets protect the operator using negative pressure, whereas clean benches utilize internal positive pressure to protect the product. By constantly discharging filtered air outward, clean benches ensure the workspace remains dust-free.
Types of Clean Benches
Clean benches are available in various configurations to suit specific applications and installation environments.
Built-in Type
Designed without a dedicated workbench frame, allowing for integration into existing equipment or production lines.
Drying Type
Equipped with infrared lamps or heaters to perform drying processes within the clean environment.
Vibration-Isolation Type
Features a structural gap between the workbench and the main fan filter unit to prevent motor vibration from transmitting to sensitive precision instruments.
Light Table Type
Incorporates an acrylic or glass work surface with under-lighting, ideal for inspection tasks.
Utility Type (Water Supply/Drainage)
Includes a sink and faucet within the workspace for operations requiring water or liquid handling.
Exhaust Type
Designed to exhaust air from the workspace, suitable for applications where odors or heat are generated (Note: Not for biohazards).
Circulation Type
Circulates clean air internally to maintain cleanliness while minimizing external air intake.
Operating Principles
A clean bench consists of a clean box unit (fan and filter) mounted on a frame enclosed by walls on the top and sides. Air drawn from the surrounding environment is filtered to remove particulates before being supplied to the workspace.
There are two primary airflow configurations:
- Horizontal Laminar Flow: Air blows from the back of the unit toward the operator. While effective for certain tasks, air turbulence can occur behind objects or the operator's hands, potentially compromising cleanliness.
- Vertical Laminar Flow: Air blows downward from the top. This design minimizes turbulence and prevents cross-contamination between items on the bench.
Matsusada Precision primarily employs the vertical laminar flow design to ensure stable performance and superior cleanliness, though horizontal models are available upon request.
The structure and performance of our clean benches are designed in accordance with JIS B9922 standards.
JIS B9922 Standard Requirements
Key structural and performance requirements for clean benches include:
- Design that facilitates easy maintenance, inspection, and adjustment.
- Workspace surfaces that are resistant to peeling, rust, and corrosion.
- A sealed structure that prevents unfiltered air from entering the clean zone.
- Provision for proper electrical grounding.
- Use of HEPA or ULPA filters as the main filtration element.
- Filters that are durable against normal atmospheric conditions and easily accessible for replacement.
- For units handling acids, organic solvents, or toxic gases, a proper exhaust ventilation structure is required.
- Explosion-proof construction (per JIS C 0903) where applicable.
- Interlock mechanisms preventing simultaneous operation of sterilization lamps and standard lighting (unless specified).
Operational Procedures
Proper operation is critical to maintaining the clean environment:
- Wash and dry hands thoroughly.
- Disinfect hands and all tools/materials with alcohol before introducing them into the clean bench.
- Turn on the fan/filter switch to initiate airflow.
- If equipped with a sliding shutter, lower it to the appropriate working height to ensure proper air velocity and protection.
- Perform work by inserting hands through the front opening.
Selection Guide
To select the optimal clean bench, define your application requirements and installation constraints:
- Application Suitability: Does the airflow type and configuration match the intended task?
- Dimensions: Does the unit fit the installation space and carry-in path?
- Budget: Does the model offer the best cost-performance ratio?
- Specifications: Do the cleanliness level (ISO Class), airflow velocity, and load capacity meet requirements?
- Filtration Efficiency: Is the dust collection efficiency sufficient for the target particle size?
Recommended Clean Benches
Matsusada Precision offers clean benches featuring lightweight, high-rigidity aluminum frames. These units are customizable to fit specific dimensions and applications. Equipped with casters for mobility, our clean benches are designed for easy integration and cost-effective deployment in industrial and research environments.
