Air Flow Damper Tension Spring Return for Stable Pressure Control
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Solution Overview
Problem
Existing air flow control dampers in ventilation systems are not stable over wide intervals of flow-rates and pressures due to fragile bellows and lack of return force from spring leaves, leading to delayed control and instability in air flow regulation.
Innovation Solution
A control damper with a cylindrical body, adjustable flap, and a tension spring that returns the flap to a nominal position, ensuring stable flow-rate control across varying pressures, and incorporating adjustment and damping mechanisms for precise control and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bellows is used to move the flap away from the support when pressure increases, then the damper can automatically balance pressure variations, but the bellows is relatively fragile and causes a delay in control when pressure varies
Solution Approach 1:
The invention removes the bellows component from the system and replaces it with a diaphragm. This extraction of the problematic element eliminates the fragility and delay issues while maintaining the pressure compensation function through the diaphragm's direct mechanical response to pressure changes.
Solution Approach 2:
The invention replaces the complex mechanical bellows system with a simpler diaphragm-based mechanism. The diaphragm directly transmits pressure forces to the flap through a lever arm, eliminating the delayed and fragile bellows expansion/contraction mechanism while achieving the same pressure-responsive control function.
2Reliability
If a leaf spring is used to bring the flap back into abutment against the support, then the flap returns to nominal position when pressure decreases, but the leaf spring has no return force when the flap is in the nominal position
Solution Approach 1:
The invention replaces the static leaf spring with a dynamic torsion spring mounted on an adjustable shaft. This allows the spring to provide continuous rotational torque around the flap's pivot axis, maintaining return force throughout the entire range of motion including at the nominal position, where the leaf spring previously failed.
Solution Approach 2:
The invention changes the type of elastic element from a leaf spring to a torsion spring, fundamentally altering the mechanical parameters of the return force mechanism. The torsion spring provides rotational torque rather than linear force, enabling continuous return force generation including at the nominal position where the leaf spring's force becomes zero.
3Ease of operation
If the nominal angular position of the flap is adjusted manually, then the user can define a specific flow-rate, but the control stability deteriorates when air flow pressure varies
Solution Approach 1:
The invention introduces a feedback mechanism where the torsion spring continuously adjusts the flap position in response to pressure changes. The spring torque automatically compensates for pressure variations by rotating the flap back toward the nominal position, providing active feedback control that maintains flow-rate stability while preserving manual adjustability of the nominal position.
Solution Approach 2:
The torsion spring mechanism enables the damper to self-adjust to pressure variations without external intervention. The spring automatically generates the necessary torque to counteract pressure-induced flap displacement, allowing the system to maintain stable flow control autonomously while the user retains the ability to manually set the nominal position.
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 provides a robust and long-lasting damper that maintains stable air flow rates over a wide pressure range, with improved control stability and reduced noise, even at minimal air flow pressures, by using a tension spring and damping member for effective regulation.
Implementation Method 1
the return device comprises a tension spring with a first end and an opposite second end, where the first end is connected to an attachment point on the shaft, and the second end is connected to an attachment point provided on the flap, so that the spring is tensioned when the flap is in the nominal position
Data Source
AI summary
Control damper including a body, defining a duct with an axis of blowing, and a control device, including a flap for closing the duct, the flap being movable in rotation with respect to the body about a pivot axis orthogonal to the axis of blowing, means for adjusting a nominal position of the flap, and a return device returning the flap to the nominal position when the flap is moved away from the nominal position. For an improved control, the means for adjusting further includes a shaft pivotally mounted with respect to the body about an axis of adjustment, wherein an angular position of the shaft about the axis of adjustment is adjustable, and at least one control cam limiting movements of the flap between the nominal position and an open position, wherein the return device includes a spring that is tensioned when the flap is in the nominal position.