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, with orthogonal arrangement of valve bodies, transverse ports, and a pressure equalizing mechanism, allowing for independent control of flow rates and reducing the need for high spring loads, thereby optimizing dimensions and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electrically operated valve is used to control 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 divided into two independent control mechanisms: a first control valve for large flow rates and a second control valve for small flow rates. This segmentation allows each valve to be optimized for its specific flow range, maintaining precision while reducing overall system complexity.
Solution Approach 2:
The valve system dynamically switches between the first and second control valves based on the required flow rate. The second valve body can be rotated to either block the first valve port (for small flow control) or open it (for large flow control), enabling adaptive optimization.
2Reliability
If a large spring load is used to prevent unintended valve opening, then valve reliability is improved, but the valve size and power consumption increase
Solution Approach 1:
The valve utilizes refrigerant pressure differential to assist in keeping the valve closed. The high-pressure side and low-pressure side create a natural balancing force that reduces the spring load requirement, thereby reducing power consumption while maintaining reliability.
Solution Approach 2:
The spring force is counterbalanced by the refrigerant pressure differential across the valve. This counteracting force reduces the net spring load needed to maintain valve closure, decreasing the energy required to operate the valve.
3Measurement precision
If the second valve port bore diameter is increased to improve small flow rate control, then flow rate control precision is improved, but pressure loss increases and controllable flow rate range is reduced
Solution Approach 1:
The valve ports are segmented into a first valve port for large flow rates and a second valve port for small flow rates. Each port has an optimized bore diameter suitable for its specific flow range, allowing precise small flow control without excessive pressure loss.
Solution Approach 2:
The system dynamically selects which valve port to use based on the required flow rate. The second valve port with smaller bore diameter is used for precision small flow control, while the first valve port with larger bore diameter is used for large flow rates, optimizing the balance between precision and pressure loss.
Data Source
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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), and is structured such that in the case that a lift amount of a 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 a 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.