Shut-off Valve With Control Member for Positive Closure
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Solution Overview
Problem
Existing shut-off valves, such as those described in EP 1 195 547, cannot guarantee that the water flow will be completely prevented when closed due to reliance on differential pressure, which may not always be sufficient, especially in mains water supplies to domestic dwellings, making them unsuitable to replace traditional stop-cocks.
Innovation Solution
A shut-off valve design incorporating a diaphragm valve and a pilot valve with a control member, including a compression spring, that holds the valve member against the seat, ensuring closure even with low differential pressures or back-pressures, and allowing remote operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diaphragm valve is used with reliance on differential pressure for closure, then the valve structure is simple and can be remotely operated, but the valve cannot guarantee complete flow prevention when differential pressure is insufficient
Solution Approach 1:
The valve is divided into two functional parts: a diaphragm valve for remote operation and a separate control member with valve member and valve seat for ensuring positive closure. The diaphragm valve handles the remote actuation function while the control member handles the reliable shut-off function, allowing each component to be optimized for its specific purpose without requiring a single complex design to do everything
Solution Approach 2:
The control member acts as an intermediary mechanism between the diaphragm valve and the main flow path. It provides the additional mechanical assurance of closure that the diaphragm valve alone cannot guarantee under low differential pressure conditions, while still allowing the diaphragm valve to maintain its simple structure and remote operation capability
2Adaptability or versatility
If the valve is designed to operate with low differential pressure, then the valve is more adaptable to mains water supply conditions, but the valve member may not remain firmly closed against back-pressure
Solution Approach 1:
The control member provides a counteracting mechanical force that opposes back-pressure on the valve member. This counterforce ensures that the valve member remains firmly seated on the valve seat even when differential pressure is low or when back-pressure attempts to force the valve open, maintaining reliable closure under varying mains water supply conditions
3Ease of operation
If a traditional stop-cock is replaced by a remote-operated valve, then the ease of operation is improved for elderly or infirm users, but the complexity of the valve mechanism increases
Solution Approach 1:
The valve mechanism is segmented into a remote-operable diaphragm valve component and a separate control member. This segmentation allows the remote operation function to be provided by the simpler diaphragm valve while the control member handles the mechanical closure assurance, avoiding the need for a single complex mechanism to perform both functions
Solution Approach 2:
The control member is designed to be automatically actuated by the diaphragm valve operation. When the diaphragm valve is operated remotely, it triggers the control member to move the valve member to the closed position, eliminating the need for separate manual operation of the control member and maintaining ease of use while ensuring reliable closure
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 valve remains closed under various pressure conditions, including low differential and back-pressures, enabling it to replace traditional stop-cocks and providing reliable shut-off capabilities, especially for domestic water supplies, while being remotely operable.
Implementation Method 1
a control member, including a compression spring, that holds the valve member against the seat
Implementation Method 2
Operation of the diaphragm valve relies upon the differential pressure between the inlet and the outlet
Data Source
AI summary
This invention relates to a shut-off valve, and primarily to a valve for shutting-off the flow of a fluid such as a mains water supply to commercial premises or a domestic dwelling. The shut-off valve (10) comprises a diaphragm valve and a pilot valve (30). The diaphragm valve has an inlet (14) and an outlet (16), a valve member (26) and a valve seat (22), the valve member having a closed position in which it engages the seat and prevents the flow of fluid from the inlet to the outlet, and an open position in which the valve member does not engage the seat and fluid can flow from the inlet to the outlet. A first fluid conduit (36) connects the inlet of the diaphragm valve to the inlet of the pilot valve, and a second fluid conduit (40) connects the outlet of the pilot valve to the outlet of the diaphragm valve. The pilot valve has an open position in which fluid can flow from the first fluid conduit to the second fluid conduit and a closed position in which fluid cannot flow from the first fluid conduit to the second fluid conduit. The invention is characterized in that the diaphragm valve has a control member (42, 44, 46) which is adapted to hold the valve member against the valve seat, whereby the diaphragm valve remains closed even if the pressure at its outlet equals or perhaps exceeds the pressure at its inlet.