Proportional Valve Geometry for Stable Low-Flow Shower Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional proportional valves in electric showers experience an initial transient surge of water when opening, due to sudden fluid flow peaks at low flow rates under mains water pressure, which existing solutions have not adequately addressed.

Innovation Solution

The design of the diaphragm plate and main orifice is modified to inhibit transient fluid flow peaks by reducing the pilot orifice size and shaping the diaphragm plate so that the gap through the main orifice increases approximately linearly with movement, reducing the rate of pressure differential and fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pilot orifice size is reduced, then transient flow peaks are inhibited, but the rate of pressure differential increase is reduced

Engineering Contradiction:

Improveflow stabilityVSAvoidpressure differential build-up rate

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent applies parameter changes by modifying the pilot orifice dimensions and the diaphragm plate geometry to achieve a linear gap increase. This changes the flow characteristics and pressure build-up rate to eliminate transient peaks while maintaining controlled flow progression.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs curved surfaces on the diaphragm plate that interact with the main orifice to create a linearly increasing gap. The specific curvature profile ensures gradual flow increase rather than sudden opening, thereby preventing water hammer and transient surges.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the diaphragm plate gap increases linearly, then transient flow peaks are reduced, but the valve response time is extended

Engineering Contradiction:

Improveflow control stabilityVSAvoidvalve activation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements preliminary action through the pre-designed linear gap geometry of the diaphragm plate. The gradual opening profile is built into the component design, so the linear flow increase occurs automatically as part of the normal valve operation, not as a separate control step.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If conventional proportional valve design is used, then flow control is achieved, but transient surge occurs at low flow rates

Engineering Contradiction:

Improveflow control capabilityVSAvoidtransient water surge

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by giving different geometric characteristics to different parts of the diaphragm plate. Specifically, the portion of the diaphragm plate that forms the gap with the main orifice has a tailored curvature profile that ensures linear gap increase, while other parts maintain standard functional characteristics.

Inventive Principle:

Principle #3Local quality

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

This design significantly reduces transient flow peaks and improves flow control, achieving a more stable and proportional flow rate from 0.5 to 12 litres per minute across 0.5-5 bar dynamic water pressure without the need for additional components.

Implementation Method 1

the solenoid has an armature that, in the absence of a signal being applied to the field winding of the solenoid, is biased by a spring to pass through the control chamber and abut the diaphragm plate

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 3

The fluid pressure in the control chamber assists in holding the diaphragm plate in the main orifice, so that no fluid flows from the inlet port to the outlet port when no signal is applied to the field winding of the solenoid

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentUS11788644B2Proportional valve, electric shower incorporating the proportional valve and tap incorporating same

Publication Date: 2023.10.17 HYDRALECTRIC GRP

AI summary

A proportional valve is provided that comprises an input port (3) and an output port (5), with a diaphragm (19) therebetween. A diaphragm plate (21) with a pilot orifice (31) formed therethrough is mounted to the diaphragm (19). The valve has a solenoid (7) comprising an armature (15) and a field winding (17), with the armature being movable in an opening direction in response to a magnetic field generated by the field winding. A spring assembly (13) is arranged to provide a biassing force to the armature (15) in its closing direction. In its closed position, the diaphragm plate (21) sits in a main orifice (20) between the input and output ports to block flow of fluid therebetween, with the armature (15) blocking the pilot orifice (31). Opening movement of the armature (15) opens the pilot orifice (31) to allow fluid to flow therethrough, in turn allowing the diaphragm plate (21) to move out of the main orifice (20) to create a gap allowing flow of fluid from the input port (3) to the output port (5). The diaphragm plate (21) and main orifice (20) are configured such that in at least the initial opening movement of the diaphragm plate, the rate of increase of the gap between them changes approximately linearly.