Electric Valve Seat Geometry for Low-Flow Rate Control
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Solution Overview
Problem
Conventional electric valves face challenges in managing rising flow rates and controllability in low flow ranges, particularly with the use of R32 refrigerant and increased partial load operations, due to complex dimensional measurements and potential corner generation during machining, leading to insufficient flow rate reduction and resolution issues.
Innovation Solution
The electric valve design incorporates a constricted surface portion with a smaller outer diameter between the seating and curved surface portions, along with a straight portion of constant diameter, to suppress corner generation and maintain a larger curved surface diameter, thereby reducing rising flow rates and enhancing low-flow range controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous curved surface portion is used to reduce rising flow rate, then flow rate control improves, but dimensional measurement becomes complicated
Solution Approach 1:
The valve body surface is segmented into distinct portions: a seating surface portion, a constricted surface portion with smaller diameter, and a curved surface portion. This segmentation allows each portion to have specific functional characteristics while enabling simplified dimensional measurement at the constricted surface, resolving the contradiction between flow control performance and measurement simplicity.
2Productivity
If the curved surface diameter is reduced to lower rising flow rate, then flow rate management improves, but corner generation occurs during machining
Solution Approach 1:
A constricted surface portion with smaller diameter is introduced as an intermediary element between the seating surface and the curved surface portion. This intermediary structure prevents corner generation during machining while still achieving the desired rising flow rate reduction through the diameter transition, resolving the contradiction between flow rate management and manufacturing precision.
3Manufacturing precision
If the curved surface diameter is increased to avoid corner issues, then manufacturing improves, but rising flow rate increases
Solution Approach 1:
The valve body is divided into portions with different diameters: the constricted surface portion has a smaller diameter that prevents corner generation during machining, while the curved surface portion can maintain a larger diameter for manufacturing stability. This segmentation allows each portion to optimize its diameter independently, resolving the contradiction between manufacturing precision and rising flow rate control.
Data Source
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AI summary
[Object] Provided is an electric valve with which a rising flow rate can be sufficiently reduced and controllability in a low flow range can be effectively improved with management of the rising flow rate simplified. [Solving Means] A seating surface portion 14a attached to a valve seat 46a and a curved surface portion 14b inserted into a valve port 46 are disposed in a valve body 14 and a constricted surface portion 14c smaller in outer diameter than an upper end portion of the curved surface portion 14b is provided between the seating surface portion 14a and the curved surface portion 14b.