Composite valve
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Solution Overview
Problem
Existing composite valves for heat pump systems face challenges in achieving precise flow rate control in small flow rate regions while minimizing pressure loss and reducing electric power consumption, often requiring large spring loads and increased size, which complicates the design and increases costs.
Innovation Solution
A composite valve design featuring a pilot type first control valve for large flow rates and a second control valve for small flow rates, where the second valve body is driven independently to optimize dimensions and shape for small flow rate control, and the pilot valve is energized downward by a spring member with a catch mechanism to prevent undesired opening, reducing the need for high spring loads and allowing for efficient flow rate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrically operated valve is used to achieve both cooling and heating functions, then the system size is reduced and cost is lowered, but the flow rate control precision in small flow rate regions deteriorates and pressure loss increases
Solution Approach 1:
The valve is segmented into two independent control valves: a first control valve with a large valve bore for large flow rates and a second control valve with a small valve bore for small flow rates. Each valve handles specific flow rate ranges, allowing the system to maintain high flow rate control precision while reducing pressure loss in small flow rate regions.
Solution Approach 2:
Different parts of the valve system have different characteristics optimized for their specific functions. The first control valve has a large valve bore optimized for large flow rates, while the second control valve has a small valve bore optimized for small flow rates. This local optimization resolves the contradiction between system size reduction and flow rate control precision.
2Measurement precision
If the valve bore diameter is made small to improve flow rate control precision, then control precision improves, but pressure loss increases and controllable flow rate decreases
Solution Approach 1:
The valve system is divided into two segments: a first control valve with a large valve bore for handling large flow rates with minimal pressure loss, and a second control valve with a small valve bore for precise small flow rate control. This segmentation allows the system to achieve both precise control and low pressure loss by directing flow through the appropriate valve based on flow rate requirements.
3Reliability
If a large spring load is used to prevent undesired valve opening, then valve stability improves, but the valve size and electric power consumption increase
Solution Approach 1:
A catch mechanism acts as an intermediary between the spring member and the valve body. The catch mechanism engages with the valve body at specific positions to prevent undesired opening, allowing the use of a smaller spring load while maintaining valve stability. This reduces the electric power consumption required to operate the valve.
Solution Approach 2:
The catch mechanism provides self-locking functionality by engaging with the valve body to maintain the closed position. This self-service mechanism prevents undesired valve opening without requiring a large continuous spring load, thereby reducing the energy consumption of the electric motor.
4Measurement precision
If the second valve body is driven independently with optimized dimensions, then small flow rate control precision improves, but the device complexity increases
Solution Approach 1:
The first and second control valves are merged into a single integrated valve body structure. Both valves share common components such as the valve body, sealing structures, and actuation mechanisms, which reduces the overall device complexity while maintaining the benefits of independent control for different flow rate ranges.
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 enhances flow rate control precision in small flow rate regions, increases controllable flow rates, reduces pressure loss, and decreases electric power consumption by optimizing the second valve's dimensions and shape, preventing undesired openings, and minimizing the size and cost of the valve system.
Implementation Method 1
a pilot valve body (20) which is driven so as to be opened and closed by utilizing the elevating motion of the valve shaft (25)
Implementation Method 2
a first valve chamber (11), a back pressure chamber (16) which is zoned by the first valve body (15), a second valve chamber (21) in which the pilot valve body (20) and the second valve body (24) are arranged so as to be movable up and down
Data Source
Figure 1
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AI summary
The invention provides a composite valve which can achieve both an improvement of a flow rate control precision in a small flow rate region and an increase of a controllable flow rate (a reduction of a pressure loss), can securely prevent a second valve body from being undesirably opened, and can achieve a cost reduction, a downsizing, a reduction of an electric power consumption and the like. The composite valve is provided with a communication path (29) which communicates a first valve chamber (11) with a second valve chamber (21), a second valve port (23) which communicates the second valve chamber (21) with an outflow port (6), and a pilot passage (19) which communicates a back pressure chamber (16) with the outflow port (6), a first valve body (15) and a second valve body (24) are arranged so as to be moved up and down in the same direction, and are away from each other only at a predetermined distance, and the composite valve is structured such that in the case that a lift amount of the second valve body (24) for a small flow rate control is equal to or less than a predetermined amount (Tc), the pilot passage (19) is closed by a pilot valve body (20), and a first valve port (13) is closed by the first valve body (15), thereby taking a small flow rate control state in which a flow rate is controlled in correspondence to the lift amount of the second valve body (24), and in the case that the lift amount of the second valve body (24) goes beyond the predetermined amount (Tc), the pilot valve body (20) is moved up in conjunction with the upward movement of a valve shaft (25) so as to open the pilot passage (19), thereby taking a large flow rate control state in which the first valve body (15) opens the first valve port (13) on the basis of this.