Blower Device Bypass Flow Path Balances Fan Pressure
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Solution Overview
Problem
Blower devices with air dynamic pressure bearings face pressure differences between fan surfaces, leading to potential contact with the housing and limiting pressure enhancement in cascade-connected systems, reducing reliability and efficiency.
Innovation Solution
A blower device design incorporating a housing with intake and exhaust ports, a motor, fan, and a sealing member, featuring a bypass flow path that reintroduces air from the gap between the fan and housing to the fan's surface, balancing pressure and enhancing reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blower device uses an air dynamic pressure bearing to reduce contact and noise, then operating life is extended and noise is reduced, but pressure difference between fan surfaces causes fan displacement and potential contact with housing
Solution Approach 1:
A communication hole is provided in the housing to allow air flow between the first surface side and second surface side of the fan. This intermediary passage balances the pressure difference that causes fan displacement, preventing fan contact with the housing while maintaining the benefits of the air dynamic pressure bearing system.
2Power
If blower devices are connected in series to enhance pressure, then pressure enhancement is achieved, but pressure imbalance between lower-stage and upper-stage blowers increases fan contact risk
Solution Approach 1:
The communication hole in the housing acts as a pressure-balancing intermediary that equalizes air pressure between the fan surfaces. This prevents the exacerbated pressure imbalance that occurs in cascade-connected blower systems, maintaining reliable operation even when multiple blowers are connected in series for enhanced pressure output.
3Power
If the fan operates at high pressure in cascade-connected systems, then pressure enhancement is achieved, but the pressure difference between fan surfaces increases causing greater fan displacement
Solution Approach 1:
The communication hole provides a pressure-balancing pathway that maintains fan position stability even during high-pressure operation in cascade-connected systems. By allowing air to flow between the fan surfaces through the housing, the system achieves pressure enhancement while preventing excessive fan displacement.
4Ease of manufacture
If the fan is positioned closer to the housing to improve sealing, then sealing efficiency is improved, but pressure difference causes greater fan-to-housing contact risk
Solution Approach 1:
The communication hole in the housing serves as a pressure-balancing intermediary that allows the fan to be positioned closer to the housing for improved sealing efficiency. The hole equalizes pressure between fan surfaces, preventing the pressure difference from causing fan contact with the housing even at reduced clearance.
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
The solution effectively suppresses pressure differences between fan surfaces, preventing contact with the housing and improving the reliability and power efficiency of blower devices, especially in cascade-connected systems, while maintaining stable operation for applications like artificial respirators.
Implementation Method 1
a blower device provided with an air dynamic pressure bearing in which at the time of, for example, rotation, the rotor and stator are not in contact with each other
Implementation Method 2
a pressure difference occurs between top surfaces and undersurfaces of fan blades
Data Source
AI summary
A blower device includes a housing including an intake chamber, an accommodation chamber communicating with the intake chamber, and an exhaust port, a motor provided in the accommodation chamber and including a coil, a fan provided on a rotating shaft of the motor, a sealing member configured to seal up the intake chamber, and a flow path of the air which is introduced into a gap between a first surface of the fan and the housing, is returned from a flow path hole provided in the housing and communicating with the intake chamber to an opening, and is introduced to a second surface of the fan opposed to the first surface by an air-blowing operation of the fan.