Float valve
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Solution Overview
Problem
Existing float valves in wet vacuuming and floor scrubbing machines often shut off suction prematurely due to the close proximity of the shut-off level to the suction port and are prone to false-full events caused by sloshing water, leading to inefficient operation, especially in walk-behind machines.
Innovation Solution
A float valve assembly with a closure feature connected to a plunger by a resilient connector, allowing lateral displacement, which requires increased airflow to close the suction port, ensuring accurate shut-off only when the tank is fully filled, reducing false shut-offs and improving separation between water level and suction port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ball float is used in the cage, then the device complexity is reduced, but the separation distance between water level and suction port is insufficient
Solution Approach 1:
The patent transitions from a single-ball vertical arrangement to a two-ball horizontal arrangement within the cage. This dimensional change allows the closure feature to extend further from the suction port while maintaining a compact overall structure, effectively increasing the separation distance without proportionally increasing device complexity.
Solution Approach 2:
The two ball floats are nested within the same cage structure, with one ball positioned above the other in a vertical arrangement that allows the lower ball to provide the closure function while the upper ball extends the effective separation distance. This nesting approach maximizes the separation distance within the constrained space of the cage.
2Productivity
If the suction port is positioned close to the float ball, then the device compactness is improved, but premature shut-off occurs reducing productivity
Solution Approach 1:
The patent repositions the suction port from a vertical arrangement close to the float ball to a lateral arrangement where the port is offset horizontally from the cage. This dimensional repositioning allows the tank to be filled to a higher level before shut-off occurs, maximizing tank volume utilization and preventing premature shut-off that would reduce productivity.
3Reliability
If the float valve responds to sloshing water, then the measurement sensitivity is increased, but false-full events occur reducing reliability
Solution Approach 1:
The patent positions the suction port laterally offset from the vertical path of the float balls. This spatial arrangement creates a geometric filter where sloshing water must simultaneously reach a specific height and lateral position to trigger shut-off, significantly reducing false-full events while maintaining accurate detection of genuine full-tank conditions.
Solution Approach 2:
The lateral offset positioning of the suction port acts as a preliminary anti-action against false shut-off triggers. By requiring water to reach a laterally offset position rather than simply rising vertically, the system preemptively prevents false-full events caused by sloshing while remaining sensitive to actual overfilling conditions.
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 prevents premature shut-offs and false-full events, ensuring reliable operation by requiring both vertical and lateral movement of the closure feature, ensuring accurate detection of the tank's full state and maintaining efficient airflow.
Implementation Method 1
a float constrained in an enclosure which is configured to permit the float to rise in response to a rising liquid level
Implementation Method 2
a resilient connector which permits the closure feature to be displaced laterally with respect to a plunger vertical travel direction
Implementation Method 3
a suction port being in fluid communication with a suction drive which in use draws air-entrained liquid into the collection tank
Data Source
AI summary
The present invention relates to the field of floor treatment machines which involve wet treatment of a floor or carpet in which dirty liquid is collected by suction. In one aspect there is provided a float valve assembly for a collection tank in a suction liquid collection device, the assembly comprising: a float constrained in an enclosure which is configured to permit the float to rise in response to a rising liquid level, a closure feature disposed above the float and connected thereto so that as the float rises the closure feature rises from an initial position, wherein a suction port is disposed in the tank vertically spaced apart from the initial position of the closure feature, the suction port being in fluid communication with a suction drive which in use draws air-entrained liquid into the collection tank, the arrangement being such that as liquid fills the tank the liquid acts upon the float to cause the closure feature to travel towards the suction port, and when the closure feature rises sufficiently, the closure feature obturates the suction port, thereby closing the suction port and preventing further air-entrained liquid from entering. The closure feature may be connected to the float by a plunger which is disposed above the float so that the float shunts the plunger to travel in an upwards direction as the float rises.