Ejector having an actuation mechanism with a pilot valve and an equalization passage between two cylinder chambers
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Solution Overview
Problem
Fast opening or closing of ejectors in refrigeration circuits leads to pressure peaks, causing instability and potential damage, and existing solutions like stepper motors are expensive and not universally suitable.
Innovation Solution
An ejector design with a needle and actuating mechanism, including a cylinder, piston, and pilot valve, that allows for smooth opening and closing without the need for expensive stepper motors, using a solenoid valve and a resilient member to control the needle's movement, ensuring slow and controlled transitions to prevent pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the ejector opens or closes quickly, then the response time is improved, but pressure peaks occur causing instability and potential damage
Solution Approach 1:
A needle valve is introduced as an intermediary component between the actuator and the main fluid passage. The needle valve gradually opens or closes the fluid passage, mediating the transition to prevent sudden pressure changes while maintaining responsive control. The needle's tapered geometry allows progressive area change for smooth pressure transition.
Solution Approach 2:
The needle valve position is dynamically adjusted during the opening/closing process rather than being in fixed positions. The actuator controls the needle's continuous movement to modulate the fluid passage area progressively, enabling dynamic pressure control that prevents peaks while maintaining system responsiveness.
2Ease of operation
If a stepper motor is used to control opening and closing, then smooth operation is improved, but device complexity and cost increase
Solution Approach 1:
A pneumatic or hydraulic actuator replaces the stepper motor to control the needle valve. The actuator uses fluid pressure to move the needle smoothly and controllably. This approach achieves smooth operation through fluid dynamics rather than complex mechanical stepping mechanisms, reducing overall system complexity and cost.
Solution Approach 2:
The mechanical stepper motor system is replaced with a fluid-based actuation system. The actuator uses pneumatic or hydraulic pressure to control the needle valve, substituting complex mechanical precision control with simpler fluid pressure control that achieves the same smooth operation goal with less complexity.
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 ensures smooth and reliable opening and closing of the ejector, preventing pressure peaks and reducing the risk of damage, while being cost-effective and not requiring expensive stepper motors, thus stabilizing the refrigeration system.
Implementation Method 1
an equalization passage for allowing fluid to flow from the first cylinder chamber to the second cylinder chamber
Implementation Method 2
a drain passage with a pilot valve, wherein the second cylinder chamber is in fluid communication with the secondary inlet and/or the outlet via the drain passage when the pilot valve is in an open state
Implementation Method 3
a cylinder with a piston connected to the needle, wherein a first cylinder chamber is maximized when the needle is in its opened position and a second cylinder chamber is maximized when the needle is in its closed position
Data Source
Figure 1
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Figure 3
AI summary
The present invention relates to an ejector (1), e.g. for a refrigerant circuit, with a primary inlet (2), a secondary inlet (7), an outlet (12), a nozzle (5), and a mixing portion (6, 10). The ejector (1) comprises an actuating mechanism (30) moving a needle (20) between an opened position and a closed position. For ensuring smooth opening and closing, the actuation mechanism (30) comprises a piston (31) in a cylinder (35), wherein a first cylinder chamber (37) is in fluid communication with the primary inlet (2) and a second cylinder chamber (38) is in fluid communication with the first cylinder chamber (37) via an equalization passage (32). The second cylinder chamber (38) is in fluid communication with the secondary inlet (7) and/or the outlet (12) via a drain passage (39, 53, 54, 55, 56, 57) when a pilot valve (50) arranged in the drain passage (39, 53, 54, 55, 56, 57) is in an open state.