Flow Volume Limiting Device With Automatic Reset Cam
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Solution Overview
Problem
Existing flow volume limiting devices require manual reset and are not suitable for automatic operation, making them inadequate for preventing flooding in applications like washing machines where uncontrolled liquid flow needs to be managed.
Innovation Solution
A flow volume limiting device with an elastomeric friction clutch that automatically couples and decouples the rotary drive connection between the flow measuring system and valve control member, using a valve piston and disk for flow control, and a reset cam for self-resetting functionality, ensuring reliable and adjustable flow volume limiting without manual intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual reset is used in flow volume limiting devices, then device complexity is reduced, but automation capability is lost
Solution Approach 1:
The device automatically resets itself through the interaction of the turbine, cam mechanism, and valve assembly. After flow stops, the turbine decelerates, the cam follower drops into the reset notch, and the spring automatically returns the valve to the open position without any manual intervention, making the system self-serviceing
Solution Approach 2:
The device operates in periodic cycles of opening, flow limitation, and automatic resetting. The cam mechanism with its operational notch and reset notch creates a periodic motion pattern that automatically cycles the valve between open and closed states based on flow conditions, enabling automated periodic operation
2Productivity
If manual operation is required to initiate liquid delivery, then device complexity is reduced, but productivity is decreased
Solution Approach 1:
The turbine provides continuous feedback about flow conditions to the cam mechanism. When flow is present, the turbine rotates and drives the cam to the operational position, automatically initiating and sustaining flow delivery. When flow stops, the turbine stops and the cam automatically resets, creating an automatic feedback-controlled system
Solution Approach 2:
The patent replaces manual mechanical operation with an automatic mechanical sensing and actuation system. The turbine-cam mechanism substitutes for manual lever operation, using fluid-driven mechanical sensing to automatically control the valve based on flow conditions
3Reliability
If gears are mechanically unmeshed for reset, then reliability of reset is improved, but device complexity and loss of time increase
Solution Approach 1:
The cam mechanism is segmented into distinct functional zones: the operational portion that drives the valve closed during flow, and the reset notch that automatically returns the cam to its initial position. This segmentation allows the reset function to be separated from the flow control function, enabling reliable automatic resetting without complex gear disengagement
Solution Approach 2:
Instead of using a complex mechanism to actively reset the valve, the patent uses the natural deceleration and stopping of the turbine when flow ceases. The cam follower passively drops into the reset notch under gravity or spring force, inverting the approach from active reset to passive automatic reset, thereby reducing complexity and reset time
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 device effectively limits liquid flow to a predetermined volume, automatically resets, and prevents flooding by engaging and disengaging the clutch based on flow presence, ensuring reliable operation and minimizing manual inputs.
Implementation Method 1
A friction clutch interconnects the flow measuring assembly and the control element for rotating the control element in a first direction when the clutch is engaged. The friction clutch is exposed to a liquid pressure differential in the flow path for engaging the clutch when flow is present and disengaging the clutch when flow is absent.
Implementation Method 2
A flow responsive piston slides along the flow path in downstream and upstream directions and a spring biases the piston in the upstream direction.
Implementation Method 3
A valve member cooperates with the valve seat to permit and prevent flow through the flow passage.
Implementation Method 4
A flow volume measuring assembly has an output shaft rotating in response to flow in the flow path.
Data Source
AI summary
A turbine wheel and gear system rotate an output shaft in response to flow, where the output shaft is connected to a clutch cup that engages a clutch and valve disk. The disk cooperates with a valve seat formed on a piston to permit/prevent flow within the piston. During flow, the clutch clamps to the disk, and the piston and disk move downstream until an associated control member hits a stop, opening the valve (as the disk stops), while the piston continues downstream. The clutch rotates the disk and control member, and if a maximum flow volume occurs, the control member rotates to an interrupt position and is released from the stop, closing the valve. Passages allow restricted flow to disengage the clutch and permit a spring to move the piston and valve upstream until engaging a reset cam that rotates the control member back to an initial position.