Diaphragm Control Valve for Variable Displacement Compressor
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Solution Overview
Problem
Existing control valves for variable displacement compressors have limited effective pressure receiving surface areas, making it difficult to balance suctioning pressure with small variations in solenoid thrust, especially when high suctioning pressures like CO2 are used, leading to larger apparatus sizes.
Innovation Solution
A control valve with a diaphragm assembly in the pressure sensitive part, composed of bonded diaphragm units forming a sealed pressure chamber, which imparts a first biasing force based on introduced pressure and a second biasing force from a solenoid thrust, allowing for adjustment of valve opening with small solenoid thrust variations and enabling a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bellows assembly is used in the pressure sensitive part, then the control valve can balance suctioning pressure with solenoid thrust, but the effective pressure receiving surface area is limited and the apparatus size becomes large when high suctioning pressures are used
Solution Approach 1:
The patent replaces the bellows assembly with a diaphragm that has a large effective pressure receiving surface area. The diaphragm is a flexible thin film structure that can expand and contract in response to pressure changes, providing the necessary pressure balancing capability without requiring a large apparatus size. The diaphragm's flexible nature allows it to effectively receive pressure over a larger area while maintaining a compact overall structure.
2Measurement precision
If the effective pressure receiving surface area is increased to handle high suctioning pressures, then the pressure control precision improves, but the control valve size increases
Solution Approach 1:
The diaphragm structure enables the control valve to achieve high pressure control precision by providing a large effective pressure receiving surface area. The flexible thin film design allows the diaphragm to respond sensitively to pressure changes across its entire surface, improving measurement and control precision without requiring a proportionally larger overall valve size.
Solution Approach 2:
The patent utilizes pneumatic principles by introducing suctioning pressure directly to the diaphragm's pressure receiving surface. This pneumatic approach allows the pressure force to be distributed over the large surface area of the diaphragm, achieving precise pressure control through the relationship between pressure and area without requiring mechanical amplification mechanisms that would increase size.
3Speed
If a bellows assembly is used, then the pressure sensitive part can respond to suctioning pressure variations, but the response sensitivity is reduced when the surface area is limited
Solution Approach 1:
The diaphragm's flexible thin film structure provides superior pressure response speed compared to bellows assemblies. The diaphragm can rapidly deform in response to pressure changes across its entire surface area, eliminating the mechanical constraints and friction present in bellows structures. This results in faster and more sensitive pressure response while utilizing the full available surface area effectively.
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 diaphragm assembly allows for precise control of valve opening with small solenoid thrust variations, enabling a smaller control valve design that can handle high suctioning pressures, and rapidly varying discharge capacity in variable displacement compressors.
Implementation Method 1
a diaphragm assembly disposed in said pressure sensitive part, said diaphragm assembly being composed of at least one diaphragm unit having two diaphragms bonded together to form a sealed pressure chamber therebetween... imparts as a first biasing force to said moving member via said diaphragm holding body a thrust of said diaphragm unit generated in accordance with the pressure introduced to said pressure sensitive part
Implementation Method 2
The solenoid part 2 is disposed at one end of a cylindrical valve body 5, generates a magnetic force by supplying an electric current to a coil 6, moves the movable iron core 7 to the fixed iron core 9 side disposed in the leftward direction against a spring 8, and imparts a biasing force having a magnitude proportional to the square of the direct current value to a valve rod 10
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~6
AI summary
[PROBLEMS] To provide a small-sized control valve in which a pressure introduced into a pressure-sensitive part can control a valve opening according to the small change of thrust by a solenoid. [MEANS FOR SOLVING THE PROBLEMS] This control valve (28) includes a diaphragm assembly (64) imparting a biasing force to a moving member (50) according to the pressure introduced into the pressure-sensitive part (40). The moving member (50) is moved by the biasing force to control the valve opening. The control valve further includes a solenoid part (36) which imparts the thrust of the diaphragm assembly (64) produced according to the pressure introduced into the pressure-sensitive part (40) to the moving member (50) through a diaphragm holding body (66) as a biasing force, and imparts a biasing force capable of controlling the valve opening in cooperation with the afore-said biasing force to the moving member (50).