Compressed air device used in low-temperature environment
By introducing a temperature control mechanism into the air compression device, and using fan blades, air collecting cylinders and aperture adjustment components to adjust the air flow rate and temperature, the problem of the operation of the air compression device in an extremely cold environment is solved, and the normal operation and efficiency of the device in an extremely cold environment is achieved.
Patent Information
- Application Number
- CN202421474572.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2034-06-26
AI Technical Summary
In extremely cold environments, the filters of existing air compression devices condensate due to low temperature environments, which affects the conversion efficiency.
A compressed air device for a low temperature environment is designed, and a structure including a mounting box, an air compression structure and a temperature control mechanism. The temperature control mechanism drives the fan blades to rotate by driving the motor, and uses the air retention tube and the aperture adjustment component to adjust the air flow rate and temperature to ensure the constant temperature inside the installation box.
It effectively solves the problem of the operation of the air compression device in low-temperature environments, and ensures the normal operation and efficiency of the device in extremely cold environments.
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Figure CN222615521U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of air compression devices, and in particular to a compressed air device for use in a low-temperature environment. Background Art
[0002] In extremely cold environments, compressed air energy storage systems can be used as a large-scale physical energy storage technology to provide solutions for load peak shaving and valley filling for power grids and to alleviate the problems of wind and solar power abandonment. The system stores compressed heat energy and high-pressure air potential energy during low-load periods, switches to power generation mode during peak power consumption periods, provides active power to the power grid, and switches to phase modulation mode after completing the task to provide dynamic reactive power support for the power grid.
[0003] In the prior art, an air compression device is disclosed, including a gas compressor, an air storage tank, a separator and a filter. The gas compressor compresses the air and the air enters the air storage tank, the filter and the separator in sequence, and is finally output for use.
[0004] With regard to the above-mentioned prior art, when the air compression device is used in an extremely cold environment, the operation of the machine will be affected by the low temperature. In particular, when the ambient temperature of the filter is extremely low, the compressed air passing through the filter will condense on the filter, thereby affecting the final conversion efficiency. Utility Model Content
[0005] In view of this, the present application provides a compressed air device for use in a low-temperature environment, which solves the problem of poor ability to resist low-temperature environments in the prior art and ensures that the temperature inside the installation box is constant.
[0006] The present application provides a compressed air device for use in a low temperature environment using the following technical solutions:
[0007] A compressed air device for use in a low-temperature environment, comprising an installation box, an air compression structure and a temperature control mechanism, wherein a door panel is provided on one side of the installation box, and an air inlet and an air outlet are provided on one side of the door panel, wherein the air inlet and the air outlet are symmetrically arranged with the door panel as a symmetry axis, and the air compression structure is arranged in the installation box for compressing air and then cooling it;
[0008] The temperature control mechanism includes a control box, a drive motor, fan blades, a hot air blower, an air collecting tube and an aperture adjustment component, the control box is arranged outside the installation box, the drive motor is arranged in the control box, the fan blades are fixedly connected to the drive end of the drive motor, the air collecting tube is truncated cone-shaped and there are multiple of them, the multiple air collecting tubes are located between the installation box and the fan blades, and the end of the air collecting tube with a small aperture is connected to the side wall of the installation box, there are multiple aperture adjustment components, multiple aperture adjustment components are arranged in the installation box, symmetrically arranged with the small aperture diameter of the air collecting tube as the symmetry axis, the aperture adjustment component is used to adjust the aperture size of the small aperture end of the air collecting tube, the control box is provided with a vent on the side away from the installation box, the vent is provided with an electric push rod, the electric push rod is provided with a closed door, the closed door is used to block the vent, there are multiple hot air blowers, and the multiple hot air blowers are all arranged in the installation box.
[0009] By adopting the above technical scheme, when the temperature in the installation box rises or falls and cannot maintain the required constant temperature, the temperature control mechanism can be controlled to adjust the temperature. When the hot air blower heats the installation box and makes the temperature too high, the drive motor is turned on to drive the fan blades to rotate. The wind generated by the rotation of the fan blades flows through the end with a larger aperture of the wind collecting tube to the end with a smaller aperture, thereby achieving the effect of cooling the air. When the temperature in the installation box rises to a certain level, the aperture of the wind collecting tube and the installation box at the same end can be further reduced through the aperture adjustment component to further accelerate the cooling of the installation box. When the temperature is too low, the closed door is closed to prevent external cold air from entering the installation box, and then the hot air blower is driven to heat the installation box to ensure that the temperature inside the installation box is constant.
[0010] Optionally, the aperture adjustment assembly includes a first cylinder, a first adjustment plate, a second cylinder and a second adjustment plate, the first cylinder is symmetrically arranged on the left and right sides of the small aperture end of the air collecting tube, the first adjustment plate is fixedly connected to the first cylinder, the second cylinder is symmetrically arranged on the upper and lower sides of the air collecting tube, and the second adjustment plate is fixedly connected to the second cylinder.
[0011] By adopting the above technical solution, when the temperature inside the installation rises to a certain level, the cold air blown into the installation box after the fan blades pass through the wind collecting tube cannot achieve a specific cooling effect. At this time, the two first cylinders are driven to push, so that the two first adjustment plates are docked, and further cooling is achieved by reducing the aperture of the wind collecting tube close to one end of the installation box. The second cylinder and the second adjustment plate achieve a cooling effect in the same way, thereby ensuring the constant temperature inside the installation box.
[0012] Optionally, both the first adjustment piece and the second adjustment piece are arc-shaped, and the inner diameter formed by the two first adjustment pieces being butted together is larger than the inner diameter formed by the two second adjustment pieces being butt-jointed together.
[0013] By adopting the above technical solution, the two first adjusting pieces are connected to the opening of the wind concentrator near one end of the installation box, and the diameter of the circular ring formed by the two first adjusting pieces and the two second adjusting pieces is the same as the aperture size of the opening of the wind concentrator near one end of the installation box, thereby changing the air temperature output by the wind concentrator, thereby achieving the purpose of regulating the temperature inside the installation box.
[0014] Optionally, the temperature control mechanism also includes a temperature sensor and a controller, the temperature sensor is arranged in the installation box, the controller is arranged in the control box, and the controller is electrically connected to the temperature sensor, the drive motor, the first cylinder, the second cylinder and the electric push rod.
[0015] By adopting the above technical solution, the temperature sensor can sense the temperature inside the installation box. When the temperature is too high, the temperature sensor transmits the temperature data to the controller, and the controller controls the electric push rod to open the closed door, and at the same time controls the drive motor to drive the fan blades to rotate, thereby cooling the inside of the installation box. When the temperature rises to a certain level, the controller controls the first cylinder to push the first adjusting plate to adjust the aperture of the wind collecting tube close to the side of the installation box, or controls the second cylinder to push the second adjusting plate to adjust the aperture of the wind collecting tube close to the side of the installation box, thereby further making the wind blown into the installation box cooler, thereby achieving the purpose of lowering the internal temperature of the installation box. When the internal temperature of the installation box is too low, the temperature sensor will feed back to the controller, and the controller will control the electric push rod to close the closed door, and at the same time control the drive motor to stop running, thereby realizing the regulation of the internal temperature of the installation box.
[0016] Optionally, the air compression structure includes a compressor, a storage tank, a filter cartridge 1, a dryer, a filter cartridge 2, a separator, a refrigerator and an operating box, wherein the operating box is disposed below the air inlet, and the compressor, storage tank, filter cartridge 1, a dryer, filter cartridge 2, a separator and a refrigerator are sequentially arranged along the circumference of the installation box and are sequentially connected, and the refrigerator is located below the air outlet. The installation box is also provided with an input port and an output port, wherein the input port is connected to the compressor, and the output port is connected to the refrigerator, and there are multiple hot air blowers, and the multiple hot air blowers are all disposed in the installation box.
[0017] By adopting the above technical solution, air is input into the compressor from the input port for air compression, and the compressed air will enter the storage tank for storage. When the compressed air in the storage tank needs to be used, the compressed air will enter the filter cartridge 1 from the storage tank for initial filtration, and the filtered compressed air will enter the dryer for drying, and then enter the filter cartridge 2 for further filtration. The filtered compressed air will enter the separator, and the oil in the compressed air will be separated by the separator. The separated compressed air is cooled by the refrigerator and output from the output end. The whole process can provide purer compressed air. When the internal temperature of the installation box is lower than 25°C, which affects the normal operation of the compression device, when the temperature sensor senses the temperature drop, the operation box controls the hot air blower to turn on to increase the internal temperature of the installation box, and the controller controls the electric push rod to close the closed door to block the entry of cold air.
[0018] Optionally, the temperature sensor sets a temperature gradient of 30-35°C and the corresponding controller controls the relative movement of the two first cylinders.
[0019] By adopting the above technical solution, when the temperature sensor senses that the temperature inside the installation box reaches 30-35°C, the controller will control the first cylinder to push the first adjustment plate to adjust the aperture of the air collecting tube to cool the inside of the installation box, which can more efficiently achieve the purpose of temperature control inside the installation box.
[0020] Optionally, the temperature sensor sets a temperature gradient of 36-40° C. and the corresponding controller controls the relative movement of the two second cylinders.
[0021] By adopting the above technical solution, when the temperature sensor senses that the temperature inside the installation box reaches 36-40°C, the controller will control the first cylinder to push the first adjustment plate to adjust the aperture of the air collecting tube to cool the inside of the installation box, which can more efficiently achieve the purpose of temperature control inside the installation box.
[0022] To summarize, the present application includes the following beneficial technical effects: when the temperature inside the installation box is too high, the controller will control the closed door to open, and at the same time drive the driving motor to rotate, driving the fan blades to blow wind into the wind collecting tube, and the wind collecting tube will allow the wind blown out by the fan blades to enter and exit from the large aperture end, and blow it out from the small aperture end into the installation box, thereby cooling the wind blown out by the fan blades, and thus making the cooling effect more significant. Under the action of the first cylinder, the first adjusting plate, the second cylinder, and the second adjusting plate, the aperture of the wind collecting tube close to the installation box can be further limited to become smaller, thereby further cooling the wind blown out by the fan blades, thereby improving the effect of reducing the temperature inside the installation box. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0024] Figure 1 A schematic diagram of the planar structure of a compressed air device for use in a low-temperature environment is disclosed for an embodiment of the present application;
[0025] Figure 2 A plan view of a compressed air device for use in a low temperature environment is disclosed in an embodiment of the present application;
[0026] Figure 3 A plan cross-sectional view of a compressed air device for use in a low-temperature environment is disclosed for an embodiment of the present application;
[0027] Figure 4 A three-dimensional cross-sectional view of a control box of a compressed air device for use in a low-temperature environment is disclosed in an embodiment of the present application;
[0028] Figure 5 Another cross-sectional view of a compressed air device for use in a low-temperature environment is disclosed as an embodiment of the present application.
[0029] Explanation of the accompanying drawings: 1. air compression structure; 11. compressor; 12. storage tank; 13. freezing separation assembly; 131. filter cartridge one; 132. dryer; 133. filter cartridge two; 134. separator; 135. refrigerator; 14. operating box; 2. temperature control structure; 21. control box; 211. vent; 212. electric push rod; 213. closed door; 22. drive motor; 23. fan blade; 24. air collecting tube; 25. aperture adjustment assembly; 251. first cylinder; 252. first adjustment plate; 253. second cylinder; 254. second adjustment plate; 26. temperature sensor; 27. controller; 28. hot air blower; 3. installation box; 31. door panel; 32. air inlet; 33. air outlet; 34. input port; 35. output port. DETAILED DESCRIPTION
[0030] The embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0031] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.
[0032] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.
[0033] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0034] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.
[0035] The present application provides a compressed air device for use in a low temperature environment. Figure 1-Figure 5 , including an installation box 3, an air compression structure 1 and a temperature control mechanism 2. A door panel 31 is hinged on one side of the installation box 3. An air inlet 32 and an air outlet 33 are provided on the installation box 3. The air inlet 32 and the air outlet 33 are symmetrically arranged with the door panel 31 as a symmetry axis. The air compression structure 1 is installed in the installation box 3 and is used to compress the air and then cool it down.
[0036] Reference Figure 4 and Figure 5The temperature control mechanism 2 includes a control box 21, a drive motor 22, a fan blade, a hot air blower 28, an air collecting tube 24 and an aperture adjustment component 25. The control box 21 is welded to the outside of the installation box 3, the drive motor 22 is welded inside the control box 21, the fan blade is fixedly connected to the driving end of the drive motor 22 by bolts, the air collecting tube 24 is truncated and has multiple air collecting tubes 24, and the multiple air collecting tubes 24 are located between the installation box 3 and the fan blades, and the end of the air collecting tube 24 with a small aperture is connected to the side wall of the installation box 3 and welded. The number of the air collecting tubes 24 disclosed in this embodiment is four, and the aperture adjustment component 2 There are multiple aperture adjustment components 25, which are arranged in the installation box 3 and are symmetrically arranged with the small aperture diameter of the air collecting tube 24 as the symmetry axis. The aperture adjustment components 25 are used to adjust the aperture size of the small aperture end of the air collecting tube 24. A ventilation hole 211 is opened on the side of the control box 21 away from the installation box 3. An electric push rod 212 is welded on the ventilation hole 211. A closed door 213 is welded on the top pushing end of the electric push rod 212. The closed door 213 is used to block the ventilation hole 211. There are multiple hot air blowers 28, and the multiple hot air blowers 28 are fixed in the installation box 3 by bolts.
[0037] Reference Figure 4 and Figure 5 The temperature control mechanism 2 also includes a temperature sensor 26 and a controller 27. The temperature sensor 26 is fixed in the installation box 3 by bolts, and the controller 27 is fixed in the control box 21 by bolts. The controller 27 is electrically connected to the temperature sensor 26, the drive motor 22, the first cylinder 251, the second cylinder 253 and the electric push rod 212.
[0038] The aperture adjustment assembly 25 includes a first cylinder 251, a first adjustment plate 252, a second cylinder 253 and a second adjustment plate 254. There are two of each of the first cylinder 251, the first adjustment plate 252, the second cylinder 253 and the second adjustment plate 254. The two first cylinders 251 are symmetrically welded on the installation box 3 and are located on the left and right sides of one end of the small aperture of the air collecting cylinder 24. The first adjustment plate 252 is welded to the pushing end of the first cylinder 251. The two second cylinders 253 are symmetrically welded to the installation box 3 and are located on the upper and lower sides of the air collecting cylinder 24. The second adjustment plate 254 is welded to the second cylinder 253. The pushing ends of the two first cylinders 251 are arranged opposite to each other, and the pushing ends of the two second cylinders 253 are arranged opposite to each other. The first adjustment plate 252 and the second adjustment plate 254 are both arc-shaped. The inner diameter formed by the two first adjustment plates 252 being connected is larger than the inner diameter formed by the two second adjustment plates 254 being connected.
[0039] The temperature sensor 26 is set with a constant temperature of 25°C, a temperature gradient of 30-35°C and a temperature gradient of 36-40°C. The temperature gradient of 30-35°C corresponds to the controller 27 controlling the relative movement of the two first cylinders 251, and the temperature gradient of 36-40°C corresponds to the controller 27 controlling the relative movement of the two second cylinders 253.
[0040] Reference Figure 2 and Figure 3 The air compression structure 1 includes a compressor 11, a storage tank 12, a filter cartridge 131, a dryer 132, a filter cartridge 133, a separator 134, a refrigerator 135 and an operation box 14. The operation box 14 is placed below the air inlet 32 of the installation box 3. The compressor 11, the storage tank 12, the filter cartridge 131, the dryer 132, the filter cartridge 133, the separator 134 and the refrigerator 135 are sequentially arranged along the circumference of the installation box 3 and are sequentially sealed and connected through stainless steel pipes. The refrigerator 135 is located below the air outlet 33 of the installation box 3. On the installation box 3, an input port 34 is opened behind the compressor 11, and an output port 35 is opened behind the refrigerator 135. The input port 34 is connected to the compressor 11 through a stainless steel pipe, and the output port 35 is connected to the refrigerator 135 through a stainless steel pipe.
[0041] The principle of this embodiment is as follows: the compressor 11 is controlled by the operation box 14 to start running, the air flowing into the input port 34 is compressed, and then stored, filtered, dried, filtered again, oil and gas are separated, and finally the compressed air is cooled and cooled, and the compressed air is finally output from the output port 35;
[0042] In the process of compressing the air, the hot air blower 28 heats the inside of the installation box 3 to maintain the internal temperature of the installation box 3 at 25°C, thereby ensuring that all mechanisms can operate normally in an extremely cold environment. When the internal ambient temperature of the installation box 3 is in the range of 25-29°C, the temperature sensor 26 transmits a temperature signal to the controller 27, and the controller 27 controls the electric push rod 212 to open the closed door 213, so that air enters the control box 21. At the same time, the controller 27 controls the driving motor 22 to rotate, driving the fan blades to rotate, and blowing the wind from the wind collecting tube 24 into the installation box 3, so as to cool down and regulate the internal temperature of the installation box 3;
[0043] When the internal ambient temperature of the installation box 3 is in the range of 30-35°C, the temperature sensor 26 transmits a temperature signal to the controller 27, and the controller 27 controls the two first cylinders 251 to push toward each other, so that the two first adjustment pieces 252 are butted, thereby changing the aperture of the air collecting tube 24 close to the box body to become smaller;
[0044] When the internal ambient temperature of the installation box 3 is in the range of 36-40°C, the temperature sensor 26 transmits a temperature signal to the controller 27, and the controller 27 controls the two first cylinders 251 to withdraw backwards, and controls the two second cylinders 253 to drive the second adjustment plates 254 to push forwards and dock, thereby further reducing the aperture of the air collecting tube 24 close to the box body;
[0045] When the internal temperature of the installation box 3 is lower than 25°C, the temperature sensor 26 feeds back a temperature signal to the controller 27, and the controller 27 controls the electric push rod 212 to push the closed door 213 to block the vent 211, and controls the drive motor 22 to stop rotating, thereby regulating the internal ambient temperature of the installation box 3;
[0046] In summary, the temperature control mechanism 2 can control the internal ambient temperature of the installation box 3 in different temperature gradients, so that the internal ambient temperature of the installation box 3 is moderately maintained at about 25°C, thereby achieving the purpose of making the internal ambient temperature of the installation box 3 reach a constant temperature.
[0047] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.
Claims
1. A compressed air device for use in a low temperature environment, characterized in that: The invention comprises an installation box (3), an air compression structure (1) and a temperature control mechanism (2); a door panel (31) is provided on one side of the installation box (3), and an air inlet (32) and an air outlet (33) are provided on the side of the door panel (31); the air inlet (32) and the air outlet (33) are symmetrically arranged with the door panel (31) as a symmetry axis; the air compression structure (1) is arranged in the installation box (3) and is used for compressing air and then cooling it; The temperature control mechanism (2) comprises a control box (21), a drive motor (22), a fan blade, a hot air blower (28), an air collecting tube (24) and an aperture adjustment component (25); the control box (21) is arranged outside the installation box (3); the drive motor (22) is arranged inside the control box (21); the fan blade is fixedly connected to the drive end of the drive motor (22); the air collecting tube (24) is truncated and has a plurality of them; the plurality of air collecting tubes (24) are located between the installation box (3) and the fan blade; and the end of the air collecting tube (24) with a smaller aperture is connected to the side wall of the installation box (3). The aperture adjustment components (25) are provided in a plurality and are arranged in the installation box (3) and are symmetrically arranged with the diameter of the small aperture of the air collecting tube (24) as the symmetry axis. The aperture adjustment components (25) are used to adjust the aperture size of the small aperture end of the air collecting tube (24). A ventilation opening (211) is provided on a side of the control box (21) away from the installation box (3). An electric push rod (212) is provided on the ventilation opening (211). A closed door (213) is provided on the electric push rod (212). The closed door (213) is used to block the ventilation opening (211).
2. A compressed air device for use in a low temperature environment according to claim 1, characterized in that: The aperture adjustment assembly (25) includes a first cylinder (251), a first adjustment plate (252), a second cylinder (253) and a second adjustment plate (254); the first cylinder (251) is symmetrically arranged on the left and right sides of the small aperture end of the air collecting tube (24); the first adjustment plate (252) is fixedly connected to the first cylinder (251); the second cylinder (253) is symmetrically arranged on the upper and lower sides of the air collecting tube (24); the second adjustment plate (254) is fixedly connected to the second cylinder (253).
3. A compressed air device for use in a low temperature environment according to claim 2, characterized in that: The first adjustment piece (252) and the second adjustment piece (254) are both arc-shaped, and the inner diameter formed by the two first adjustment pieces (252) being butt-jointed is larger than the inner diameter formed by the two second adjustment pieces (254) being butt-jointed.
4. A compressed air device for use in a low temperature environment according to claim 3, characterized in that: The temperature control mechanism (2) further comprises a temperature sensor (26) and a controller (27); the temperature sensor (26) is arranged in the installation box (3); the controller (27) is arranged in the control box (21); the controller (27) is electrically connected to the temperature sensor (26), the drive motor (22), the first cylinder (251), the second cylinder (253) and the electric push rod (212).
5. The compressed air device for use in a low temperature environment according to claim 1, characterized in that: The air compression structure (1) comprises a compressor (11), a storage tank (12), a first filter cartridge (131), a dryer (132), a second filter cartridge (133), a separator (134), a refrigerator (135) and an operation box (14); the operation box (14) is arranged below the air inlet (32); the compressor (11), the storage tank (12), the first filter cartridge (131), the dryer (132), the second filter cartridge (133), the separator (134) and the refrigerator (135); and a refrigerator (135) are sequentially arranged along the circumference of the installation box (3) and are sequentially connected; the refrigerator (135) is located below the air outlet (33); an input port (34) and an output port (35) are also provided on the installation box (3); the input port (34) is connected to the compressor (11); the output port (35) is connected to the refrigerator (135); there are a plurality of hot air blowers (28), and the plurality of hot air blowers (28) are all arranged in the installation box (3).
6. A compressed air device for use in a low temperature environment according to claim 4, characterized in that: The temperature sensor (26) is provided with a temperature gradient of 30-35°C, and the corresponding controller (27) controls the relative movement of the two first cylinders (251).
7. A compressed air device for use in a low temperature environment according to claim 4, characterized in that: The temperature sensor (26) sets the temperature gradient to 36-40°C and the corresponding controller (27) controls the relative movement of the two second cylinders (253).