Pulse tube cryocooler
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Solution Overview
Problem
The existing pulse tube cryocooler's DC flow regulation mechanism is complex, costly, and difficult to independently control flow rates and DC flow due to the incorporation of an orifice in the needle valve, which complicates the design and manufacturing process.
Innovation Solution
A pulse tube cryocooler design featuring a bidirectional flow path with a DC flow generator that causes different pressure drops for inflow and outflow, and a flow rate regulator to adjust flow rates, utilizing a DC flow generator with distinct tapered portions and a temperature regulator to manage flow path resistances and temperature differences for independent regulation of DC flow and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a needle valve with an incorporated orifice is used to regulate DC flow, then DC flow regulation is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The flow rate regulator is divided into multiple independent adjustment mechanisms: a needle valve for controlling total flow rate and a separate orifice for controlling DC flow. This segmentation allows independent regulation of each parameter without affecting the other, resolving the complexity issue while maintaining reliable DC flow control.
Solution Approach 2:
The orifice is extracted from the needle valve structure and positioned as a separate component in the flow path. This extraction simplifies the overall device design by separating the DC flow control function from the total flow rate control function, making each component simpler and easier to manufacture while maintaining both control capabilities.
2Reliability
If an orifice is incorporated in the needle valve, then DC flow is regulated, but ease of operation deteriorates due to interdependence of flow rate and DC flow
Solution Approach 1:
The control system is segmented into two independent adjustment mechanisms: the needle valve controls total flow rate while the orifice controls DC flow. This segmentation enables operators to adjust each parameter independently without the interdependence caused by the incorporated orifice design, significantly improving ease of operation.
Solution Approach 2:
The system provides dynamic and flexible control by allowing independent adjustment of total flow rate and DC flow. Operators can first set the desired total flow rate using the needle valve, then independently adjust the DC flow component using the orifice, enabling precise control adaptability to different operational requirements.
3Reliability
If the flow path geometry differs according to flow direction, then DC flow is generated, but manufacturing precision requirements increase
Solution Approach 1:
The orifice is positioned asymmetrically relative to the pulse tube flow path, creating different flow resistances for forward and reverse flows. This asymmetric positioning generates the desired DC flow effect while using a simple geometric feature that is easy to manufacture with standard precision, avoiding the need for complex asymmetric flow path geometries.
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 configuration simplifies DC flow regulation, reduces interdependence between flow rate and DC flow, and facilitates easier independent adjustment, enhancing refrigeration performance by managing excessive DC flow and maintaining refrigeration efficiency.
Implementation Method 1
a DC flow generator that is disposed in the bidirectional flow path, causes a first pressure drop in the pulse tube inflow, and causes a second pressure drop different from the first pressure drop in the pulse tube outflow
Implementation Method 2
a flow rate regulator that is disposed in the bidirectional flow path in series with the DC flow generator, and adjusts flow rates of the pulse tube inflow and the pulse tube outflow
Implementation Method 3
a pulse tube cryocooler that cools an object to be cooled
Data Source
AI summary
A pulse tube cryocooler includes a pulse tube; a bidirectional flow path that is connected to the pulse tube, and through which a pulse tube inflow and a pulse tube outflow alternately flow; a DC flow generator that is disposed in the bidirectional flow path, causes a first pressure drop in the pulse tube inflow, and causes a second pressure drop different from the first pressure drop in the pulse tube outflow; and a flow rate regulator that is disposed in the bidirectional flow path in series with the DC flow generator, and adjusts flow rates of the pulse tube inflow and the pulse tube outflow.