Flow control valve
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Solution Overview
Problem
Flow control valves for refrigerant in heat pump systems face issues with noise generation due to pressure fluctuations and refrigerant separation, and existing designs with linear flow characteristics struggle to reduce noise and pressure loss when applied to equal percentage flow characteristics.
Innovation Solution
A flow control valve with a valve orifice that has sequentially increasing diameters in three stages, along with truncated conical tapered surfaces, to gradually restore pressure and reduce vortex and cavitation, achieving a smoother flow and lower noise levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a curved surface portion with ellipsoidal spherical shape is provided on the valve element to obtain equal percentage flow characteristic, then the flow characteristic is improved, but the processing cost and manufacturing complexity increase
Solution Approach 1:
The curved surface portion is divided into multiple conical tapered surface portions (first, second, third conical tapered surface portions) with different control angles. Each portion has a specific orifice diameter ratio range, segmenting the continuous ellipsoidal spherical surface into discrete manufacturable sections that are easier to produce while maintaining the equal percentage flow characteristic.
Solution Approach 2:
The invention specifies precise parameter ranges for the conical tapered surface portions, including orifice diameter ratios (D2/D1: 1.05-1.45, D3/D2: 1.00-1.50) and control angles (θ1: 3°-10°, θ2: 5°-15°, θ3: 7°-20°). These parameter changes transform the complex ellipsoidal spherical surface into a series of conical surfaces with controlled geometric parameters that are more manufacturable while preserving the desired flow characteristic.
2Volume of moving object
If the valve orifice has a sudden change in diameter to achieve compact design, then the device size is reduced, but pressure fluctuations and noise increase due to vortex and cavitation
Solution Approach 1:
The invention uses conical tapered surface portions with gradually increasing control angles (θ1 < θ2 < θ3) to create a smooth curved transition in the valve orifice. This curvature approach replaces sudden diameter changes with gradual transitions, preventing vortex and cavitation formation while maintaining compact valve dimensions. The continuous change in surface angle ensures smooth refrigerant flow through the orifice.
3Object-generated harmful factors
If the valve orifice length is increased to suppress noise and pressure fluctuations, then the noise reduction is improved, but the pressure loss increases and flow rate decreases
Solution Approach 1:
The invention applies different local geometric qualities to different sections of the valve orifice. The first conical tapered surface portion has a smaller control angle θ1 for gradual pressure adjustment, the second has a medium angle θ2 for transition, and the third has a larger angle θ3 for final pressure restoration. This localized quality variation allows noise suppression through gradual pressure change while minimizing overall pressure loss and maintaining flow rate.
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 suppresses pressure fluctuations and noise, reduces pressure loss, and maintains an appropriate refrigerant flow rate by optimizing orifice diameters and lengths, resulting in a more efficient and quieter operation.
Implementation Method 1
the orifice diameter of the valve orifice is sequentially increased in three or more stages in a direction away from the valve chamber, so that pressure fluctuations when a refrigerant flows through the valve orifice are suppressed
Implementation Method 2
a sudden fluctuation in the pressure or a refrigerant separation phenomenon is likely to occur, whereby a vortex or cavitation is likely to occur and grow
Data Source
Figure 1
Figure 2(A)~2(B)
Figure 3(A)~3(B)
AI summary
Provided is a flow control valve that can effectively reduce the generation of noise due to fluctuations in the pressure or a refrigerant separation phenomenon that may occur while a refrigerant passes through the valve orifice, and also reduces the pressure loss and the like. The flow control valve includes a valve body 5 including a valve chamber 6 and a valve orifice 10; and a valve element 30 with a curved surface portion 33 adapted to change the flow rate of a fluid through the valve orifice 10 in accordance with the lift amount of the valve element 30, the curved surface portion 33 having a curvature or a control angle that is increased continuously or in stages toward the tip end of the curved surface portion 33. The orifice diameter of the valve orifice 10 is sequentially increased in three or more stages in a direction away from the valve chamber 6. Specifically, the valve orifice 10 includes, sequentially arranged from the side of the valve chamber 6, a first valve orifice portion 11 with an orifice diameter D1, a second valve orifice portion 12 with an orifice diameter D2 (> D1), and a third valve orifice portion 13 with an orifice diameter D3 (> D2). More preferably, D1, D2, and D3 are set so that each of (the valve orifice diameter ratio: D2/D1) and (the valve orifice diameter ratio: D3/D2) is within a specific range.