Clean air device

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Solution Overview

Problem

Existing clean air devices connecting safety cabinets and clean booths fail to adequately prevent cross-contamination, particularly in regenerative medicine where cell cultivation requires high cleanliness levels, as the air from the clean booth with a lower cleanliness level can contaminate the safety cabinet through the connecting portion.

Innovation Solution

A clean air device design that includes a cabinet with a work space and a circulation flow path for air exhaustion, featuring a pass box connected to the clean booth with an outer surface slit that communicates with the circulation flow path, effectively preventing air from the clean booth from entering the cabinet by controlling airflow through HEPA filters and slits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a pass box is provided to connect the safety cabinet and clean booth for material transfer, then the convenience of operation is improved, but the risk of cross-contamination increases due to pressure differences and air flow from the clean booth side entering the safety cabinet

Engineering Contradiction:
Improveconvenience of material transferVSAvoidcross-contamination risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary air barrier mechanism at the pass box connection portion. A slit is provided on the outer surface of the pass box connection portion to supply air from the safety cabinet side toward the clean booth side, creating a unidirectional air flow that prevents reverse contamination while allowing material transfer. This intermediary air barrier resolves the contradiction by enabling operation convenience without compromising contamination prevention.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies pneumatic principles by utilizing pressure control and air flow management to prevent contamination. The circulation flow path exhausts air from the safety cabinet, creating negative pressure that prevents clean booth air from entering. Additionally, the slit at the pass box connection portion supplies pressurized air from the safety cabinet side to actively block contamination, resolving the contradiction between material transfer convenience and contamination prevention.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If the circulation flow path exhausts air from the safety cabinet to maintain negative pressure, then the protection of sample from outside bacteria is improved, but the energy consumption increases due to continuous air exhaustion

Engineering Contradiction:
Improvesample protection capabilityVSAvoidenergy consumption of air exhaustion
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by concentrating air supply at specific critical locations rather than uniform air supply throughout. The slit is strategically positioned at the pass box connection portion, which is the most vulnerable point for contamination. This localized air barrier provides effective contamination prevention with minimal energy consumption, resolving the contradiction between sample protection reliability and energy efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of air flow direction and pressure distribution. Instead of uniform air supply, the system creates localized positive pressure at the pass box connection portion through the slit, while maintaining overall negative pressure in the safety cabinet through the circulation flow path. This parameter change enables effective contamination prevention with reduced energy consumption compared to uniform air supply systems.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design significantly reduces the risk of contamination between connected safety cabinets and clean booths, maintaining aseptic conditions and high cleanliness levels by isolating the air flow and preventing external contamination.

Implementation Method 1

a circulation flow path which is formed by a lower surface side, a side surface side and a rear surface side of the work space and an outside portion of the cabinet to exhaust the air flowing into the work space

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

an outer surface slit of the pass box connection portion is provided at a lower part of the outer surface of the pass box connection

Methodology Applied
Scientific EffectAir barrier:

Data Source

PatentEP3406978B1Clean air device
Publication Date: 2024.05.01 HITACHI IND EQUIP SYST CO LTD
  • EP3406978B1 patent drawingFigure 1(A)~1(B)
  • EP3406978B1 patent drawingFigure 2
  • EP3406978B1 patent drawingFigure 3(A)~3(E)

AI summary

The purpose of the present invention is to reduce the risk of contamination in a clean air device in which a safety cabinet and clean booths are coupled. To achieve this, a clean air device in which a cabinet and clean booths are coupled, is configured such that the cabinet is equipped with: a work space which is formed on the inner side of a front shutter; and a circulation path which is formed from the lower surface, side surfaces, rear surface of the work space, and an outside portion of the cabinet so as to exhaust the air flowing into the work space. Pass boxes connected to the clean booths are provided to a portion of the side surfaces of the work space. Each of the pass boxes is formed by a pass box coupling inner surface, the outside of which has a space formed by a pass box coupling outer surface. The space communicates with the circulation path. The bottom of the pass box coupling outer surface is provided with a pass box coupling outer surface slit.