Stirling cryocooler with adjustable working medium pressure and refrigeration control method

Abstract

The invention relates to a working medium pressure-adjustable Stirling cryocooler and a refrigeration control method, and the Stirling cryocooler comprises a gas inlet container used for storing working medium gas; the air inlet valve assembly is respectively communicated with the air inlet container and a backpressure cavity of an expansion machine of the Stirling cryocooler; the controller is connected with the air inlet valve assembly and used for receiving temperature information of an expansion cavity of the Stirling cryocooler. And when the temperature of the expansion cavity of the Stirling cryocooler is not within the preset temperature range, the opening degree of the gas inlet valve assembly is controlled through the controller, so that the working medium gas in the gas inlet container enters the backpressure cavity. According to the invention, working medium pressure adjustment and motor working state control can be combined to realize rapid cooling, and the mechanical load of the motor can be reduced while the refrigeration effect is ensured.

Description

Technical Field

[0001] The invention relates to the field of Stirling refrigerators, and in particular to a Stirling refrigerator with adjustable working fluid pressure and a refrigeration control method. Background Art

[0002] When the Stirling refrigerator is working, the pressure of the gas working fluid filled is constant. Therefore, when adjusting the temperature of the expander, the controller is mostly used to adjust the working state of the motor, and then adjust the cooling capacity. For example, when the motor is a rotary motor, the temperature in the expansion chamber can be obtained in real time through the controller. When the temperature does not reach the preset value (i.e., the initial cooling stage), the controller increases the speed of the rotary motor to further increase the cooling capacity to achieve rapid cooling. When the temperature in the expansion chamber reaches the preset value (i.e., the temperature control stage), the controller reduces the speed of the rotary motor and maintains the speed at a constant level, further maintaining the temperature of the expansion chamber at the preset value. Similarly, when the motor is a linear motor, in the initial cooling stage, the controller increases the stroke of the linear motor to achieve rapid cooling, and in the temperature control stage, reduces the stroke of the linear motor to achieve constant temperature control.

[0003] However, the above temperature control method is only achieved by adjusting the working state of the motor, the overall working efficiency is low, and the load of the motor is too large, which affects the life and working reliability of the refrigerator. Summary of the invention

[0004] The object of the present invention is to provide a Stirling refrigerator with adjustable working fluid pressure and a refrigeration control method, which can combine working fluid pressure regulation with motor working state control to achieve rapid cooling and reduce the mechanical load of the motor while ensuring the refrigeration effect.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] On the one hand, a Stirling refrigerator with adjustable working fluid pressure is provided, comprising:

[0007] An air intake container, which is used to store working medium gas;

[0008] An air intake valve assembly, which is connected to the air intake container and the back pressure chamber of the expander of the Stirling refrigerator respectively;

[0009] and a controller connected to the air inlet valve assembly and used to receive expansion chamber temperature information of the Stirling refrigerator;

[0010] When the temperature of the expansion chamber of the Stirling refrigerator is not within a preset temperature range, the controller controls the opening of the air intake valve assembly so that the working fluid gas in the air intake container enters the back pressure chamber.

[0011] Preferably, when the working fluid gas in the air intake container enters the back pressure chamber, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to rotate continuously at a first speed; when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to move continuously according to a first stroke.

[0012] Preferably, the Stirling refrigerator further comprises:

[0013] A gas outlet container, which is used to store the working gas flowing out of the back pressure chamber;

[0014] An outlet valve assembly, which is connected to the outlet container and the back pressure chamber of the expander of the Stirling refrigerator, respectively, and is also connected to the controller;

[0015] When the temperature of the expansion chamber is within a preset temperature range, the controller controls the opening of the gas outlet valve assembly so that the working fluid gas in the back pressure chamber enters the gas outlet container.

[0016] Preferably, when the temperature of the expansion chamber is within a preset temperature range and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to continuously rotate at a second speed; when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to continuously move according to a second stroke to maintain the temperature of the expansion chamber within a preset temperature range.

[0017] Preferably, the first rotational speed is greater than the second rotational speed, and the first stroke is greater than the second stroke.

[0018] Preferably, the Stirling refrigerator further comprises:

[0019] A pressure sensor is installed on the expander and is used to obtain the pressure change in the back pressure chamber.

[0020] Preferably, when the pressure in the back pressure chamber increases to an upper pressure threshold, the air inlet valve assembly is closed, and / or, when the pressure in the back pressure chamber decreases to a lower pressure threshold, the air outlet valve assembly is closed.

[0021] On the other hand, a refrigeration control method based on a Stirling refrigerator is also provided, which comprises the following steps:

[0022] When the temperature of the expansion chamber is not within a preset temperature range, the controller receives the temperature information of the expansion chamber, and controls the opening of the air intake valve assembly according to the temperature of the expansion chamber, so that the working gas in the air intake container enters the back pressure chamber of the expander of the Stirling refrigerator;

[0023] When the temperature of the expansion chamber is within a preset temperature range, the controller controls the opening of the gas outlet valve assembly so that the working medium gas in the back pressure chamber of the expander of the Stirling refrigerator enters the gas outlet container.

[0024] Preferably, when the temperature of the expansion chamber is not within the preset temperature range, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to continuously rotate at a first speed, and when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to continuously move according to a first stroke;

[0025] And, when the temperature of the expansion chamber is within a preset temperature range, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to continuously rotate at a second speed, and when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to continuously move according to a second stroke, so as to maintain the temperature of the expansion chamber within the preset temperature range;

[0026] Furthermore, the first rotation speed is greater than the second rotation speed, and the first stroke is greater than the second stroke.

[0027] Preferably, when the pressure in the back pressure chamber increases to an upper pressure threshold, the air inlet valve assembly is closed, and / or, when the pressure in the back pressure chamber decreases to a lower pressure threshold, the air outlet valve assembly is closed.

[0028] In summary, the present invention has the following beneficial effects compared with the prior art:

[0029] The present invention combines working fluid pressure regulation with motor working state control to reduce the expansion chamber temperature to a preset temperature range in a short time. The working state of the motor with low speed / short stroke is further combined with the method of reducing the working fluid pressure, so that the motor can maintain the expansion chamber temperature within a low temperature range under lower speed / smaller stroke conditions, thereby reducing the mechanical load of the motor while ensuring the refrigeration effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of a Stirling refrigerator in the prior art.

[0031] Figure 2 It is a schematic diagram of the overall structure of the Stirling refrigerator in the present invention. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figure 2 As shown, this embodiment provides a Stirling refrigerator with adjustable working fluid pressure, and the Stirling refrigerator can be a linear Stirling refrigerator or a rotary Stirling refrigerator, such as Figure 1 As shown, the Stirling refrigerator mainly includes: a motor 1, a connecting pipe 3, a cold finger 4, a cold accumulator 5, an expansion piston 6 and a spring 7, wherein the cold accumulator 5 (including a cold accumulator shell and an energy storage material filled in the cold accumulator shell, such as a metal wire mesh, etc.) is assembled in the cold finger 4 to form an expansion chamber 41 and a room temperature chamber 43 at both ends of the cold finger 4, and at the same time, a back pressure chamber 42 is also formed at one end of the cold finger 4 away from the expansion chamber 41 (for example, the back pressure chamber 42 is formed by enclosing structures such as the expander shell, the piston 6 and the end cover), the expansion piston 6 and the spring 7 are both located in the back pressure chamber 42, and the expansion piston 6 is connected to the spring 7; the connecting pipe 3 is connected to the compression chamber 21 and the room temperature chamber 43 respectively, and the motor 1 is used to drive the expansion piston 6 and the spring 7 to move linearly synchronously. For example, when the motor 1 is a rotary motor, the compression piston 2 is arranged in the compression chamber 21, and the motor 1 is connected to the compression piston 2 and the expansion piston 6 through an eccentric structure, so that the gas working medium enters the back pressure chamber 42 through the connecting pipe 3 through the periodic movement of the compression piston 2, so as to drive the expansion piston 6 and the spring 7 to move linearly synchronously. When the motor 1 is a linear motor, it can directly drive the expansion piston 6 and the spring 7 to move linearly synchronously, thereby compressing the working medium gas and making it enter the cold finger 4.

[0035] In addition, the Stirling refrigerator also includes:

[0036] The gas intake container 100 is used to store the working gas with a gas pressure of P1; in this embodiment, the gas intake container 100 can be made of steel;

[0037] An air intake valve assembly 10, which is connected to the air intake container 100 and the back pressure chamber 42 of the expander of the Stirling refrigerator respectively;

[0038] A pressure sensor 9, which is installed on the expander and connected to the controller 8, and is used to obtain the pressure in the back pressure chamber 42 in real time;

[0039] and a controller 8 connected to the air inlet valve assembly 10 and used to receive the expansion chamber temperature information of the Stirling refrigerator;

[0040] In the initial refrigeration stage (i.e., when the expansion chamber temperature is not within the preset temperature range), the controller 8 receives the expansion chamber temperature information of the Stirling refrigerator in real time, and controls the opening of the intake valve assembly 10 according to the expansion chamber temperature, so that the working fluid gas in the intake container 100 enters the back pressure chamber 42 to increase the pressure in the back pressure chamber 42. At the same time, when the motor 1 is a rotary motor, the controller 8 controls the motor 1 to rotate continuously at a first speed, and when the motor 1 is a linear motor, the controller 8 controls the motor 1 to move continuously according to the first stroke. This process is an inflation process;

[0041] During the inflation process, the pressure change in the back pressure chamber 42 is obtained in real time through the pressure sensor 9. When the pressure in the back pressure chamber 42 increases to the upper pressure limit threshold, the pressure sensor 9 feeds back the pressure in the back pressure chamber 42 to the controller 8. The controller 8 closes the intake valve assembly 10 according to the pressure in the back pressure chamber 42 to end the inflation process.

[0042] Therefore, since the motor 1 continues to work at a higher speed or a larger stroke (i.e., the first speed or the first stroke), the above-mentioned inflation process increases the pressure in the back pressure chamber 42. Therefore, the cooling capacity per unit time is increased by combining the high speed / long stroke working state of the motor 1 with the increase in the working fluid pressure, so that the expansion chamber temperature can be reduced to a preset temperature range in a short time, thereby greatly shortening the cooling time and improving the cooling efficiency.

[0043] Preferably, in this embodiment, the working gas pressure P1 in the air intake container 100 is greater than the initial pressure of the back pressure chamber 42. Therefore, when the air intake valve assembly 10 is opened, the working gas in the air intake container 100 can automatically flow into the back pressure chamber 42 under the action of the pressure difference without the aid of a pump or other equipment.

[0044] Embodiment 2:

[0045] The difference between this embodiment and embodiment 1 is that the Stirling refrigerator further includes:

[0046] The gas outlet container 100' is used to store the working gas flowing out of the back pressure chamber 42; in this embodiment, the gas outlet container 100' can also be made of steel;

[0047] The gas outlet valve assembly 10' is connected to the gas outlet container 100' and the back pressure chamber 42 of the expander of the Stirling refrigerator respectively;

[0048] When the temperature of the expansion chamber is within the preset temperature range (i.e., in the temperature control stage), the controller 8 controls the opening of the outlet valve assembly 10' so that the working gas in the back pressure chamber 42 enters the outlet container 100' to reduce the pressure in the back pressure chamber 42. At the same time, when the motor 1 is a rotary motor, the controller 8 controls the motor 1 to rotate continuously at the second speed. When the motor 1 is a linear motor, the controller 8 controls the motor 1 to move continuously according to the second stroke. This process is the outlet process. At the same time, the first speed is greater than the second speed, and the first stroke is greater than the second stroke.

[0049] In the above-mentioned gas outlet process, the pressure change in the back pressure chamber 42 is obtained in real time through the pressure sensor 9. When the pressure in the back pressure chamber 42 drops to the lower pressure threshold, the pressure sensor 9 feeds back the pressure in the back pressure chamber 42 to the controller 8. The controller 8 closes the gas outlet valve assembly 10' according to the pressure in the back pressure chamber 42 to end the gas outlet process.

[0050] Since the temperature of the expansion chamber has been rapidly reduced to within the preset temperature range through the high speed / long stroke working state of the motor 1 in Example 1 combined with the increase in the working fluid pressure to achieve the purpose of rapid cooling, the pressure in the back pressure chamber 42 is further reduced through the above-mentioned air outlet process, and the speed or stroke of the motor 1 is reduced at the same time, so that the motor 1 can maintain the expansion chamber temperature within the low temperature range (that is, the preset temperature range) under a lower speed / smaller stroke condition (that is, the second speed or the second stroke), so as to reduce the mechanical load of the motor 1 while ensuring the refrigeration effect.

[0051] Embodiment 3:

[0052] This embodiment provides a refrigeration control method implemented by the Stirling refrigerator described in Embodiment 2, which comprises the following steps:

[0053] S1. In the initial cooling stage (i.e., when the temperature of the expansion chamber is not within the preset temperature range), the controller 8 controls the motor 1 to continuously operate in the first state, wherein the continuous operation in the first state includes: when the motor 1 is a rotary motor, the motor 1 continuously rotates at a first speed, and when the motor 1 is a linear motor, the motor 1 continuously moves according to a first stroke;

[0054] S2, when the motor 1 is continuously working at the first speed or the first stroke, the controller receives the expansion chamber temperature information of the Stirling refrigerator in real time, and controls the opening of the air intake valve assembly 10 according to the expansion chamber temperature, so that the working fluid gas in the air intake container 100 enters the back pressure chamber 42 to increase the pressure in the back pressure chamber 42. This process is the inflation process;

[0055] S3, during the inflation process, the pressure change in the back pressure chamber 42 is obtained in real time through the pressure sensor 9. When the pressure in the back pressure chamber 42 increases to the upper pressure threshold, the pressure sensor 9 feeds back the pressure in the back pressure chamber 42 to the controller 8. The controller 8 closes the air intake valve assembly 10 according to the pressure in the back pressure chamber 42 to end the inflation process.

[0056] S4, repeating steps S2-S3 until the temperature of the expansion chamber is within the preset temperature range, the controller 8 controls the motor 1 to continuously operate in the second state to maintain the temperature of the expansion chamber within the preset temperature range, and at the same time, the controller 8 controls the opening of the outlet valve assembly 10' so that the working fluid gas in the back pressure chamber 42 enters the outlet container 100' to reduce the pressure in the back pressure chamber 42, and this process is the outlet process; the continuous operation in the second state includes: when the motor 1 is a rotary motor, the motor 1 continuously rotates at a second speed, and when the motor 1 is a linear motor, the motor 1 continuously moves according to a second stroke, and the first speed is greater than the second speed, and the first stroke is greater than the second stroke;

[0057] And S5, during the gas outlet process, the pressure change in the back pressure chamber 42 is obtained in real time through the pressure sensor 9. When the pressure in the back pressure chamber 42 drops to the lower pressure threshold, the pressure sensor 9 feeds back the pressure in the back pressure chamber 42 to the controller 8. The controller 8 closes the gas outlet valve assembly 10' according to the pressure in the back pressure chamber 42 to end the gas outlet process.

[0058] In summary, the present invention can combine the working fluid pressure regulation with the motor working state control (i.e., speed control or stroke control) to achieve rapid cooling, that is, by combining the high speed / long stroke working state of the motor with the method of increasing the working fluid pressure, the refrigeration capacity per unit time is increased, so that the expansion chamber temperature can be reduced to a preset temperature range in a short time. Further, by combining the low speed / short stroke working state of the motor with the method of reducing the working fluid pressure, the motor can maintain the expansion chamber temperature within the low temperature range under the conditions of lower speed / smaller stroke, so as to reduce the mechanical load of the motor while ensuring the refrigeration effect.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A Stirling refrigerator with adjustable working fluid pressure, characterized in that: include: An air intake container, which is used to store working gas; An air intake valve assembly, which is connected to the air intake container and the back pressure chamber of the expander of the Stirling refrigerator respectively; and a controller connected to the air inlet valve assembly and used to receive expansion chamber temperature information of the Stirling refrigerator; When the temperature of the expansion chamber of the Stirling refrigerator is not within a preset temperature range, the controller controls the opening of the air intake valve assembly so that the working fluid gas in the air intake container enters the back pressure chamber.

2. The Stirling refrigerator according to claim 1, characterized in that When the working fluid gas in the air intake container enters the back pressure chamber, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to rotate continuously at a first speed; when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to move continuously according to a first stroke.

3. The Stirling refrigerator according to claim 1, characterized in that: The Stirling refrigerator also includes: A gas outlet container, which is used to store the working gas flowing out of the back pressure chamber; An outlet valve assembly, which is connected to the outlet container and the back pressure chamber of the expander of the Stirling refrigerator, respectively, and is also connected to the controller; When the temperature of the expansion chamber is within a preset temperature range, the controller controls the opening of the gas outlet valve assembly so that the working fluid gas in the back pressure chamber enters the gas outlet container.

4. The Stirling refrigerator according to claim 3, characterized in that: When the temperature of the expansion chamber is within a preset temperature range, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to rotate continuously at a second speed; when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to move continuously according to a second stroke to maintain the temperature of the expansion chamber within a preset temperature range.

5. The Stirling refrigerator according to claim 4, characterized in that: The first rotation speed is greater than the second rotation speed, and the first stroke is greater than the second stroke.

6. The Stirling refrigerator according to claim 3, characterized in that: The Stirling refrigerator also includes: A pressure sensor is installed on the expander and is used to obtain the pressure change in the back pressure chamber.

7. The Stirling refrigerator according to claim 6, characterized in that: When the pressure in the back pressure chamber increases to an upper pressure threshold, the air inlet valve assembly is closed, and / or when the pressure in the back pressure chamber decreases to a lower pressure threshold, the air outlet valve assembly is closed.

8. A refrigeration control method based on a Stirling refrigerator, characterized in that: The steps include: When the temperature of the expansion chamber is not within a preset temperature range, the controller receives the temperature information of the expansion chamber, and controls the opening of the air intake valve assembly according to the temperature of the expansion chamber, so that the working gas in the air intake container enters the back pressure chamber of the expander of the Stirling refrigerator; When the temperature of the expansion chamber is within a preset temperature range, the controller controls the opening of the gas outlet valve assembly so that the working medium gas in the back pressure chamber of the expander of the Stirling refrigerator enters the gas outlet container.

9. The refrigeration control method according to claim 8, characterized in that: When the temperature of the expansion chamber is not within the preset temperature range, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to continuously rotate at a first speed, and when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to continuously move according to a first stroke; And, when the temperature of the expansion chamber is within a preset temperature range, and when the motor of the Stirling refrigerator is a rotary motor, the controller controls the motor to continuously rotate at a second speed, and when the motor of the Stirling refrigerator is a linear motor, the controller controls the motor to continuously move according to a second stroke, so as to maintain the temperature of the expansion chamber within the preset temperature range; Furthermore, the first rotation speed is greater than the second rotation speed, and the first stroke is greater than the second stroke.

10. The refrigeration control method according to claim 8, characterized in that: When the pressure in the back pressure chamber increases to an upper pressure threshold, the air inlet valve assembly is closed, and / or when the pressure in the back pressure chamber decreases to a lower pressure threshold, the air outlet valve assembly is closed.

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