Cris-cross flow diverter for pneumatic drill noise reduction
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Solution Overview
Problem
Surgical pneumatic drills generate significant noise due to the exhaust air returning through a coaxial hose, which existing technologies have not effectively mitigated.
Innovation Solution
The implementation of cris-cross passages in the end cap or plug of the motor and hose to divert and intersect air flows, reducing the amplitude of pressure and thus the noise level by directing half the air flow into one axial passageway and the other half into another, causing the flows to impinge and cancel each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If exhaust air is returned through a coaxial hose, then the pneumatic motor can be powered effectively, but significant noise is generated
Solution Approach 1:
The exhaust air flow is segmented into multiple separate passageways (first and second passageways) within the coaxial hose. This segmentation allows the noise from a single high-velocity stream to be divided into multiple lower-velocity streams, reducing the overall noise level while maintaining the pneumatic power function.
Solution Approach 2:
A diverter component is introduced as an intermediary element within the coaxial hose system. This diverter redirects the exhaust air flow into the segmented passageways and creates counter-flow patterns that generate negative pressure waves to cancel noise, serving as a mediator between the power transmission function and noise reduction requirement.
2Object-generated harmful factors
If air flow is directed through separate passageways, then noise amplitude is reduced, but the device complexity increases
Solution Approach 1:
The multiple passageways for exhaust air are nested within the existing coaxial hose structure. The first and second passageways are contained within the outer passage of the coaxial hose, creating a nested configuration that adds noise reduction functionality without requiring a completely new hose system, thereby limiting the increase in device complexity.
Solution Approach 2:
The coaxial hose structure is designed to serve multiple functions: it continues to provide pneumatic power transmission while simultaneously incorporating noise reduction through its nested passageway system. The diverter component also serves dual purposes by both segmenting the flow and generating noise-canceling pressure waves.
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 approach effectively reduces the overall noise level by canceling decibels, making the surgical pneumatic drills quieter and more tolerable in clinical environments.
Implementation Method 1
By virtue of flowing a portion the air to flow in separate passageways reduces the amplitude of the pressure. That flow in both passageways are then directed to cross each other. The effect of the flow crossing causes the flow to impinge on the flow from each of the passageways and this impact cancels or nearly cancels the amplitude of the pressure which results in a reduction of decibels and an overall reduction in the noise level.
Data Source
AI summary
A cris-cross pattern of flow channels serves to divide the flow of fluid and then cross the flow to cause an impact between the flow in each channel to impact against each other to reduce the decibels and noise level created by the flowing of the fluid. In a pneumatic surgical drill the spent air used to power the vane motor is diverted so that the flow of is divided in separate flow paths that cross to allow the air that flows from one of the divided channels impinges on the air flowing from the other of the divided channels. In one embodiment the divided channels or flow passageways is formed in the end cap of the housing of a pneumatic surgical drill and in another embodiment the flow diverter with the divided passageways or channels is formed in a plug the fits into the coaxial hose that connects to the housing of the pneumatic surgical drill.