Swimming Pool Safety Apparatus with Dual Pressure Switches

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Solution Overview

Problem

Existing safety apparatuses for swimming pools fail to reliably detect and respond to vacuum conditions that could suck users into suction ducts, leading to potential harm or drowning, and often lack effective fault notification and redundancy to ensure safe operation.

Innovation Solution

A safety apparatus using two pressure switches hydraulically connected to the same suction duct, with a logic unit that checks for consistency in their status to ensure accurate detection of suction pressure and generates alarms or stops the pump if inconsistencies are detected, providing active redundancy and fault notification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single pressure switch is used to detect vacuum conditions, then the device complexity is reduced, but the reliability of safety detection deteriorates due to potential switch failure

Engineering Contradiction:
Improvenumber of pressure switchesVSAvoidsafety detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by implementing a redundancy mechanism where a second pressure switch serves as a backup to the first pressure switch. If the first pressure switch fails to detect hazardous vacuum conditions, the second pressure switch provides a backup detection capability, cushioning against the reliability loss from a single point of failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies local quality by making the two pressure switches non-identical in their detection characteristics. The first pressure switch is calibrated to detect hazardous vacuum conditions at a specific threshold, while the second pressure switch has a different calibration threshold. This differentiation ensures that if one switch fails or gives false readings, the other can still provide reliable detection due to their complementary detection characteristics.

Inventive Principle:
Principle #3Local quality

2Reliability

If two pressure switches are installed to provide redundancy, then the reliability of safety detection is improved, but the device complexity increases

Engineering Contradiction:
Improvesafety detection reliabilityVSAvoidnumber of pressure switches
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control unit implements beforehand cushioning by preparing a backup detection pathway. When the first pressure switch fails or provides inconsistent readings compared to the second pressure switch, the control unit automatically switches to relying on the second pressure switch for safety detection, thus cushioning against the loss of redundancy.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies partial action by having the two pressure switches perform different functions. The first pressure switch is primarily responsible for normal hazardous vacuum condition detection, while the second pressure switch serves both as a backup for the first switch and has its own independent calibration for detecting different vacuum conditions. This partial differentiation reduces the complexity burden while maintaining reliability.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If pressure switches are calibrated to detect hazardous vacuum conditions at different thresholds, then the measurement precision is improved, but the device complexity increases due to calibration requirements

Engineering Contradiction:
Improvevacuum condition detection precisionVSAvoidcalibration requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning different calibration thresholds to the two pressure switches. The first pressure switch is calibrated for detecting hazardous vacuum conditions at one threshold level, while the second pressure switch is calibrated for detecting hazardous vacuum conditions at a different threshold level. This local differentiation in detection characteristics improves measurement precision across different vacuum condition ranges.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the calibration threshold parameter between the two pressure switches. This parameter differentiation allows the system to detect hazardous vacuum conditions more precisely across a broader range of vacuum levels, with each switch optimized for specific detection ranges.

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If the pump is stopped immediately upon detecting hazardous vacuum conditions, then the safety of users is improved, but the productivity of water circulation is reduced

Engineering Contradiction:
Improveuser safety from suctionVSAvoidwater circulation flowrate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies partial action by implementing a graduated response rather than immediate full pump shutdown. When hazardous vacuum conditions are detected, the control unit can partially reduce the pump's operating parameters or activate alternative circulation pathways, rather than completely stopping the pump. This partial action maintains some water circulation productivity while still protecting users from dangerous suction forces.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent applies beforehand cushioning by preparing alternative water circulation pathways in advance. When hazardous vacuum conditions are detected, the system can switch to alternative circulation routes that bypass the problematic suction points, cushioning against the need to completely stop the pump and maintaining water circulation productivity while still ensuring user safety.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

Ensures safe operation of swimming pools by reliably detecting and responding to hazardous vacuum conditions, preventing user entrapment and ensuring the safety apparatus operates effectively even if one pressure switch fails, with additional features for maintenance and emergency operations.

Implementation Method 1

at least two pressure switches be hydraulically connected to a same branch of the purification circuit, substantially in a same pressure-detection point of the branch detect a negative suction relative pressure in the branch

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP3674500B1A safety apparatus for a swimming pool
Publication Date: 2021.11.03 A W S TECH SRL
  • EP3674500B1 patent drawingFigure 1
  • EP3674500B1 patent drawingFigure 2
  • EP3674500B1 patent drawingFigure 3

AI summary

A safety apparatus (1) for a swimming pool (10) comprises at least two pressure switches (31,41) in use hydraulically connected in a same point (22) upstream of a pump (25) of a swimming pool water purification circuit, each pressure switch comprising a first (33,43) and a second (34,44) contact arranged to open or close when an emergency stop pressure (Pa) and a maximum operation pressure (Pe) is reached, respectively, and also comprises a logic unit (50) electrically connected to each pressure switch (31,41) and, in use, with a contactor (24) of the circulation pump (25), the logic unit (50) configured to compare the statuses of the second contacts (34,44) with each other, and for transferring a pump-stop/block electric signal (55) to the contactor (24) when a status of at least one pressure switch (31,41) it is detected which corresponds to a pressure lower than the emergency stop pressure (Pa), or when a condition is detected in which the status of the second contact (34) of one of the pressure switches (31) indicates a suction pressure lower than the maximum operation pressure (Pe), while the status (44) of the other pressure switch (41) indicates a suction pressure higher than the maximum operation pressure (Pe); in this condition, an instrument out-of-service alarm signal is also generated. In an exemplary embodiment, a key device is provided, associated with a key confidentially entrusted to a subject, which serves allow switching on the pump even in the presence of such a condition.