Bell-Shaped Valve Guide for Ventilation Noise Reduction
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Solution Overview
Problem
Valve devices in ventilation systems face issues with noise generation, pressure drop, and airflow separation due to constrictions, which are particularly problematic in positive input ventilation, and are often not dynamically adjustable without causing unforeseen side effects like increased noise and pressure drop.
Innovation Solution
The valve device features a bell-shaped airflow guide with a smooth, slidable design where the inner wall is parallel to the guide wall for most of its length, minimizing airflow acceleration and separation, and includes a support system with fins for smooth flow regulation, ensuring optimal airflow in both extraction and positive input ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a valve device forms a constriction with respect to the pipe diameter, then the air flow acceleration occurs, but noise is generated due to vibrations in the valve device
Solution Approach 1:
The guide wall is designed with a bell-shaped curve instead of sharp edges or abrupt constrictions. This curved geometry smoothly guides the airflow through the valve device, reducing turbulence and vibrations that cause noise while still achieving the necessary flow control.
Solution Approach 2:
The cross-sectional area of the guide wall varies continuously according to a bell-shaped curve rather than having abrupt changes. This gradual parameter change in the geometry allows airflow acceleration without creating the sharp constrictions that lead to vibrations and noise generation.
2Speed
If a valve device forms a constriction with respect to the pipe diameter, then the air flow acceleration occurs, but pressure drop increases due to resistance in the air flow
Solution Approach 1:
The bell-shaped curved guide wall creates a gradual expansion and contraction pattern that minimizes flow separation and turbulence. This smooth curvature reduces energy losses from eddies and vortices, maintaining lower pressure drop while still achieving flow control.
Solution Approach 2:
The design accepts that some constriction is necessary for flow control but uses the bell-shaped geometry to convert what would be harmful sharp constrictions into beneficial smooth transitions. The curvature transforms potential energy losses into manageable pressure changes.
3Adaptability or versatility
If an annular flow regulator is placed around the top of the airflow guide, then the flow rate becomes adjustable, but obstacles are created within the base that affect the airflow and may increase noise and pressure drop
Solution Approach 1:
The annular flow regulator is removed from the interior of the base and relocated to the exterior. This extraction eliminates the obstacle within the airflow path, preventing the noise and pressure drop issues that would result from having regulatory elements in the flow stream.
Solution Approach 2:
The flow regulator acts as an external intermediary that controls airflow without being in the direct path of the air stream. By positioning it externally around the top of the airflow guide, it can modulate flow rate without creating the turbulence and noise associated with internal obstacles.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A valve device for use in a ventilation system. The valve device comprises: a base (44, 46) configured to connect to a pipe and an airflow guide (50) directed toward the base. The base has an inner wall (66) with a variable diameter that decreases from an initial value (R1) on the pipe to a minimum value (R2) and then increases to a maximum value (R3) on the output side. The airflow guide is substantially bell-shaped in cross-section with a top directed towards the base. A hypothetical disc (5) positioned at the constriction of the inner wall intersects the airflow guide in an intersection line (74). Providing such a constriction ensures a concentration of the flow near the top of the airflow guide, while the placement of the top prevents the concentrated air from colliding directly with it. These effects together ensure an improved air flow over the valve device.