Thermal stress compensation device, refrigeration unit and method for compensating thermal stress thereof, cold storage

Abstract

The present invention discloses a thermal stress compensation device, a refrigeration unit and a method for compensating thermal stress therefor, and a cold storage. The thermal stress compensation device comprises: a first connecting member connected to a first component affected by thermal stress; a second connecting member connected to a second component not affected by thermal stress, or connected to a third component affected by thermal stress; and an adjustment component, the two ends of which are respectively connected to the first connecting member and the second connecting member, for adjusting the spacing between the first connecting member and the second connecting member. The present invention can compensate for strain caused by thermal stress.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal stress compensation control, and in particular to a thermal stress compensation device, and a method for compensating thermal stress when the thermal stress compensation device is applied in a refrigeration unit. Background Art

[0002] In the prior art, some refrigeration units have a low refrigeration temperature, so the difference between the refrigerant temperature and the ambient temperature in some pipelines is large. For example, the condensing unit is the most commonly used refrigeration unit in cold storage, so the refrigeration temperature of the condensing unit is much lower than that of a household air conditioner, and the difference between the refrigerant temperature and the ambient temperature in some pipelines is also greater than that of a household air conditioner. As an important component of the condensing unit, once the pipeline components are damaged, it will directly cause economic losses and even cause serious safety accidents. In particular, the tensile and compressive loads caused by thermal stress in the pipe sections with sudden changes in pipe diameter such as the condenser gas distribution pipe are most likely to cause pipeline rupture.

[0003] For example, the refrigeration temperature of the condensing unit of some cold storages is very low, and the low-temperature cold storage requires a refrigeration temperature between -23℃ and -30℃. After the installation of the condensing unit pipeline, if the flexibility of a certain section of the pipeline structure is low or the temperature difference between the inner wall temperature and the outer ring temperature of the pipeline is large, the pipeline thermal stress will be very large, especially in some places where the pipe diameter is reduced, the pipeline is very easy to break and damage, resulting in accidents such as refrigerant leakage.

[0004] In order to solve the above problems, the existing low-temperature refrigeration units basically use liquid distributors and capillaries to replace the original gas distributors. However, in some systems with more branches, the liquid distributors and capillaries have problems of inefficiency and high cost in both the design and production links. Not only does it need to design the length of each capillary separately during the design, but also the lack of good positioning and limiting during production often causes production abnormalities. Summary of the invention

[0005] In order to solve the technical problem in the prior art that deformation of components caused by thermal stress cannot be compensated, the present invention proposes a thermal stress compensation device, a refrigeration unit and a method for compensating thermal stress thereof, and a cold storage.

[0006] The thermal stress compensation device proposed by the present invention comprises:

[0007] a first connecting member connected to a first component affected by thermal stress;

[0008] A second connecting member connected to a second component not affected by thermal stress, or connected to a third component affected by thermal stress;

[0009] The adjusting component has two ends respectively connected to the first connecting member and the second connecting member, and is used to adjust the distance between the first connecting member and the second connecting member.

[0010] Further, the adjustment component comprises:

[0011] A connecting arm, wherein two connecting arms are provided, and the two connecting arms are respectively connected to the first connecting member and the second connecting member in a one-to-one correspondence, and meshing teeth are provided on opposite sides of the two connecting arms;

[0012] The gear is clamped between the two connecting arms and meshes with the meshing teeth of the two connecting arms;

[0013] A power member is connected to the gear and is used to drive the gear to rotate so as to adjust the distance between the first connecting member and the second connecting member connected to the two connecting arms.

[0014] Furthermore, the portion of the connecting arm where the meshing teeth are provided is provided with scales.

[0015] Furthermore, the thermal stress compensation device further comprises:

[0016] A detection member, used for detecting the scale of movement of the connecting arm;

[0017] The controller controls the driving member according to the scale to be moved and the detection result of the detection member.

[0018] Furthermore, the first connecting member and / or the second connecting member are detachably connected to the adjusting assembly.

[0019] The refrigeration unit proposed in the present invention includes a compressor, an indoor heat exchanger, an outdoor heat exchanger and an electronic expansion valve located between the indoor heat exchanger and the outdoor heat exchanger, a branch with one end connected to the pipeline between the outdoor heat exchanger and the electronic expansion valve and the other end connected to the suction port of the compressor, a branch electronic expansion valve arranged in the branch, and a thermal stress compensation device described in the above technical solution is installed in at least one component in the refrigeration unit where the pipe diameter changes and is subjected to thermal stress.

[0020] Furthermore, the first connecting member of the thermal stress compensation device is connected to an air distribution pipe in the outdoor heat exchanger or the indoor heat exchanger that is affected by thermal stress, and the second connecting member is connected to a component in the outdoor heat exchanger or the indoor heat exchanger that is not affected by thermal stress.

[0021] Furthermore, the refrigeration unit is a condensing unit.

[0022] The cold storage proposed by the present invention adopts the refrigeration unit described in the above technical solution.

[0023] When the first connecting piece of the thermal stress compensation device is connected to an air distribution pipe in an outdoor heat exchanger or an indoor heat exchanger affected by thermal stress, and the second connecting piece is connected to a component in the outdoor heat exchanger or the indoor heat exchanger that is not affected by thermal stress, the method for compensating thermal stress of a refrigeration unit includes:

[0024] After the refrigeration unit is powered on and before the compressor is started, the temperature T of the gas distribution pipe connected to the first connecting member is detected;

[0025] During the process from the start of the compressor to the stable operation of the compressor, the temperature Tn of the gas distribution pipe connected to the first connecting member is detected once at a preset time interval;

[0026] When n is greater than or equal to 2, calculating the thermal stress of the gas distribution pipe connected to the first connecting member;

[0027] The regulating component of the thermal stress compensation device is controlled accordingly according to the magnitude of the thermal stress.

[0028] Furthermore, the thermal stress magnitude is calculated according to the formula ε= k*[T n -T n-1 +T n -T] is calculated, ε is the thermal stress, and k is the proportionality coefficient.

[0029] Furthermore, corresponding control of the adjustment component of the thermal stress compensation device according to the magnitude of the thermal stress includes: when the magnitude of the thermal stress is less than a first preset value, the adjustment component is not adjusted, or the adjustment component is pre-adjusted so that the gas distribution pipe connected to the first connecting member is not subjected to the tensile stress of the adjustment component.

[0030] Furthermore, controlling the adjustment component of the thermal stress compensation device accordingly according to the thermal strain magnitude includes: when the thermal stress magnitude is greater than or equal to a first preset value and less than a second preset value, calculating the scale to be adjusted according to the thermal stress magnitude, and adjusting the adjustment component according to the readability to be adjusted.

[0031] Further, controlling the regulating component of the thermal stress compensation device accordingly according to the magnitude of the thermal stress includes:

[0032] When the thermal stress is greater than or equal to a second preset value, the branch electronic expansion valve is opened to spray liquid to the suction pipe of the compressor;

[0033] The opening of the electronic expansion valve is adjusted until the thermal stress value calculated most recently is smaller than the first preset value.

[0034] The present invention designs a thermal stress compensation device so that components that are affected by thermal stress and produce strain can be compensated accordingly. When the thermal stress compensation device is specifically used to compensate for pipeline thermal stress, the stress and strain of the pipeline can be reduced, the stability of pipeline operation can be improved, and the life of the pipeline can be increased. When the thermal stress compensation device is used in an evaporator, the evaporator can adopt a gas distribution pipe that is low in cost and easy to implement, without the need to use a high-cost liquid distribution head and capillary tube. The thermal stress compensation method of the present invention determines the size of the pipeline thermal stress through the pipeline working temperature and the pipeline static temperature, and compensates for the pipeline thermal stress through a device that automatically adjusts the tension / pressure and torque. It has the function of dynamically adjusting external force compensation, and can effectively perform external compensation for pipeline stress under different stress states. At the same time, the device can be adjusted more accurately by judging the trend of temperature change. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention is described in detail below with reference to the embodiments and accompanying drawings, wherein:

[0036] Figure 1 It is a structural schematic diagram of an embodiment of the thermal stress compensation device of the present invention.

[0037] Figure 2 It is a structural schematic diagram of an embodiment of a refrigeration unit of the present invention. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Thus, a feature indicated in this specification will be used to illustrate one of the features of an embodiment of the present invention, rather than implying that each embodiment of the present invention must have the described feature. In addition, it should be noted that this specification describes many features. Although some features can be combined together to illustrate possible system designs, these features can also be used in other combinations that are not explicitly described. Thus, unless otherwise stated, the described combinations are not intended to be limiting.

[0040] The principle of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0041] The thermal stress compensation device of the present invention comprises a first connector 001, a second connector 002, and an adjustment component 003 connecting the first connector 001 and the second connector 002. The two ends of the adjustment component 003 are respectively connected to the first connector 001 and the second connector 002 to adjust the distance between the first connector 001 and the second connector 002. Although the first connector 001 and the second connector 002 have different names, their structures can be the same, and only the connected parts are different.

[0042] When in use, the first connector 001 is connected to the first component affected by thermal stress, and the second connector 002 can be connected to the second component not affected by thermal stress, or can be connected to the third component affected by thermal stress. When the first connector 001 and the second connector 002 are both connected to two components affected by thermal stress, how to control the adjustment component 003 is relatively complicated, so in a preferred embodiment, the first connector 001 is connected to the first component affected by thermal stress, and the second connector 002 is connected to the second component not affected by thermal stress, so that the control of the adjustment component 003 is simpler and easier to implement.

[0043] like Figure 1 As shown, in a specific embodiment of the present invention, the adjustment component 003 includes two connecting arms 031, a gear 032 and a power member. The two connecting arms 031 are connected to the first connecting member 001 and the second connecting member 002 in a one-to-one correspondence, and the opposite sides of the two connecting arms 031 are provided with meshing teeth. The specific shape of the connecting arm in the figure includes a connecting part used to be detachably connected to the first connecting member and the second connecting member, and a rack part connected to the connecting part. The rack part can be provided with a scale, or the part of the connecting arm provided with the meshing teeth is provided with a scale. The gear 032 is clamped between the two connecting arms, and in the embodiment in the figure, it is specifically clamped between the rack parts of the two connecting arms, and the gear and the meshing teeth of the two connecting arms are meshed with each other. The power member is connected to the gear to drive the gear to rotate so as to adjust the spacing between the first connecting member and the second connecting member connected to the two connecting arms. The power member can be a motor, or a combination of a motor and a transmission component, or other mechanism for driving the gear to rotate.

[0044] The first connecting member 001 and / or the second connecting member 002 are detachably connected to the connecting arm 032, and its specific structure can adopt the detachable connection structure in the prior art. The part where the first connecting member 001 is connected to the first component can be made of a flexible material, and the part where the first connecting member 001 is connected to the connecting arm can be made of a rigid material. Similarly, the part where the second connecting member 002 is connected to the second component or the third component can be made of a flexible material, and the part where the second connecting member 002 is connected to the connecting arm can also be made of a rigid material.

[0045] In a preferred embodiment, the thermal stress compensation device may also include a detection member and a controller, wherein the detection member is used to detect the scale of movement of the connecting arm, and the controller controls the driving member according to the scale to be moved and the detection result of the detection member, so as to perform closed-loop precise control of the adjustment component.

[0046] In other embodiments, the adjustment component is not limited to Figure 1 The specific structures shown in the figure can be applied to the present invention as long as they are mechanisms that can achieve adjustable spacing between the first connecting member and the second connecting member. For example, two structures can cooperate with each other to form a slide rail that can move back and forth. Furthermore, a limit member for limiting the movement of the slide rail, a control member for controlling the action of the limit member, etc. can be provided, and the present invention is not limited to the limited number of specific implementation structures listed in the present invention.

[0047] like Figure 2 As shown, the refrigeration unit of the present invention comprises a compressor 1, an indoor heat exchanger 2, an outdoor heat exchanger 3, a drying filter 4, an electronic expansion valve 5 and a liquid supply stop valve 6 connected in series between the outdoor heat exchanger 3 and the indoor heat exchanger 2, a gas-liquid separator 8 is provided on the pipeline connecting the air intake port of the compressor 1 and the four-way steering valve 7, and an air intake temperature sensing package 9 and a low-pressure sensor 10 are provided on the pipeline between the gas-liquid separator 8 and the air intake port, a high-pressure switch 11 is provided on the pipeline between the air outlet of the compressor 1 and the four-way steering valve 7, and an air exhaust temperature sensing package 9 and a low-pressure sensor 10 are provided at the air outlet of the compressor 1. 12. The pipeline connecting the four-way steering valve 7 and the indoor heat exchanger is connected in series with an air intake filter 13 (bidirectional), an air intake stop valve 14, and a branch line, one end of which is connected to the pipeline between the outdoor heat exchanger 3 and the electronic expansion valve 5, and the other end is connected to the air intake port of the compressor 1. A branch electronic expansion valve 15 and a liquid injection capillary 16 are provided on the branch line. A branch filter 17 can also be provided between the branch electronic expansion valve and the liquid injection capillary. A branch line is also provided between the exhaust port of the compressor 1 and the outlet pipe of the gas-liquid separator 8, and an unloading solenoid valve 18 is provided on the branch line.

[0048] The thermal stress compensation device of the above technical solution is installed in at least one component of the refrigeration unit whose pipe diameter changes and is subject to thermal stress. In a specific application example, the first connector of the thermal stress compensation device is connected to an air distribution pipe in the outdoor heat exchanger or the indoor heat exchanger that is affected by thermal stress, and the second connector is connected to a component in the outdoor heat exchanger or the indoor heat exchanger that is not affected by thermal stress. For example, when the outdoor heat exchanger is used as an evaporator, the first connector of the thermal stress compensation device is installed at the sudden change of pipe diameter on the air distribution pipe of the outdoor heat exchanger. A air distribution pipe temperature sensing package 19 is also installed on the air distribution pipe. The second connector is installed on the elbow of the heat exchange copper pipe of the outdoor heat exchanger. When the unit is cooling, the first connector and the second connector both adopt a circular ring structure to wrap the pipeline to provide tensile stress. The installation of the thermal stress compensation device allows the outdoor heat exchanger to use the existing air distribution pipe, without using a liquid distributor head and a capillary tube, and the pipeline design is simpler and more convenient.

[0049] The present invention does not limit the type of refrigeration unit, and the refrigeration unit may be a condensing unit. When the refrigeration unit of the present invention is used in a cold storage, the cold storage also falls within the protection scope of the present invention.

[0050] The specific implementation steps of the method for controlling the compensating thermal stress of a refrigeration unit of the present invention are introduced below.

[0051] After the refrigeration unit is powered on and before the compressor is started, the temperature T of the air distribution pipe connected to the first connecting piece is detected. For example, after the refrigeration unit is powered on, the temperature detected by the temperature sensing package of the air distribution pipe is read immediately. At this time, the compressor is not started, and the temperature detected by the temperature sensing package of the air distribution pipe is similar to the temperature of the air distribution pipe when there is no thermal stress.

[0052] Next, during the process from the start of the compressor to the stable operation of the compressor, the temperature Tn of the air distribution pipe connected to the first connecting member is detected once at a preset time interval.

[0053] During the first detection, that is, when n=1, no processing is performed.

[0054] After the second test, when n is greater than or equal to 2, the thermal stress of the air distribution pipe connected to the first connector is calculated, and then the adjustment component of the thermal stress compensation device is controlled accordingly according to the thermal stress. The thermal stress is calculated according to the formula ε=k*[Tn-Tn-1+Tn-T], where ε is the thermal stress and k is the proportionality coefficient. The specific value of k depends on the linear expansion coefficient, elastic modulus and pipeline shape of the air distribution pipe. Different materials of the air distribution pipe have different linear expansion coefficients, elastic moduli, etc., which can be obtained through experimental data or empirical values ​​summarized by technical personnel.

[0055] When the thermal stress is less than the first preset value, that is, k*[T n -T n-1+T n -T]<ε0, the temperature change trend shows that the deformation of the air distribution pipe is small and no thermal stress compensation is required. The adjustment component may not be adjusted or the adjustment component may be pre-adjusted so that the air distribution pipe connected to the first connecting piece is not subjected to the tensile stress of the adjustment component.

[0056] When the thermal stress is greater than or equal to the first preset value, k*[T n -T n-1 +T n -T]≥ε0, it is judged that the deformation of the air distribution pipe is large and further judgment is needed.

[0057] When the thermal stress is greater than or equal to the first preset value and less than the second preset value, that is, ε0≤ k*[T n -T n-1 +T n -T]<ε1, it is judged that the deformation of the gas distribution pipe is large and external compensation is required. At this time, the scale to be adjusted is calculated according to the size of the thermal stress, and the adjustment component is adjusted according to the readability to be adjusted. Specifically, the controller sends a corresponding signal to control the drive member to drive the gear of the adjustment component to rotate, so that the connecting arm moves the corresponding scale. First calculate the adjustment ratio, adjustment ratio = (δT*k-ε0) / [ε1-ε0] = ([Tn-Tn-1+Tn-T]*k-ε0) / [ε1-ε0]. If the adjustment range of the adjustment component is m scales, the scale to be adjusted is m multiplied by the adjustment ratio.

[0058] When [T n+1 -T n +T n+1 -T]≥ε1, the thermal stress at this time reaches the fatigue limit of the pipe material of the gas distribution pipe. At this time, the branch electronic expansion valve is opened to spray liquid to the suction pipe of the compressor, and then the opening of the electronic expansion valve is adjusted to avoid the reduction of cooling capacity in the outdoor heat exchanger serving as the evaporator, until the thermal stress magnitude ε calculated most recently is less than the first preset value. That is to say, after the branch electronic expansion valve is opened, the temperature detected by the gas distribution pipe temperature sensing package is obtained again, and the latest thermal stress magnitude is calculated.

[0059] In a specific embodiment, when the gas distribution pipe connected to the first connecting member is a copper pipe, the first preset value and the second preset value can be taken according to ε1=500um and ε0=350um.

[0060] 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 and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermal stress compensation device, characterized in that: include: a first connecting member connected to a first component affected by thermal stress; A second connecting member connected to a second component not affected by thermal stress, or connected to a third component affected by thermal stress; The adjusting component has two ends respectively connected to the first connecting member and the second connecting member, and is used to adjust the distance between the first connecting member and the second connecting member.

2. The thermal stress compensation device according to claim 1, characterized in that: The adjustment component comprises: A connecting arm, wherein two connecting arms are provided, and the two connecting arms are respectively connected to the first connecting member and the second connecting member in a one-to-one correspondence, and meshing teeth are provided on opposite sides of the two connecting arms; The gear is clamped between the two connecting arms and meshes with the meshing teeth of the two connecting arms; A power member is connected to the gear and is used to drive the gear to rotate so as to adjust the distance between the first connecting member and the second connecting member connected to the two connecting arms.

3. The thermal stress compensation device according to claim 2, characterized in that: The portion of the connecting arm where the meshing teeth are provided is provided with scales.

4. The thermal stress compensation device according to claim 3, characterized in that: Also includes: A detection member, used for detecting the scale of movement of the connecting arm; The controller controls the power member according to the scale to be moved and the detection result of the detection member.

5. The thermal stress compensation device according to claim 1, characterized in that: The first connecting member and / or the second connecting member are detachably connected to the adjusting assembly.

6. A refrigeration unit, comprising a compressor, an indoor heat exchanger, an outdoor heat exchanger, and an electronic expansion valve located between the indoor heat exchanger and the outdoor heat exchanger, a branch having one end connected to a pipeline between the outdoor heat exchanger and the electronic expansion valve and the other end connected to an air intake port of the compressor, and a branch electronic expansion valve arranged in the branch, characterized in that: The thermal stress compensation device according to any one of claims 1 to 5 is installed in at least one component of the refrigeration unit whose pipe diameter changes and is subjected to thermal stress.

7. The refrigeration unit according to claim 6, characterized in that: The first connecting piece of the thermal stress compensation device is connected to an air distribution pipe in the outdoor heat exchanger or the indoor heat exchanger that is affected by thermal stress, and the second connecting piece is connected to a component in the outdoor heat exchanger or the indoor heat exchanger that is not affected by thermal stress.

8. The refrigeration unit according to claim 6 or 7, characterized in that: The refrigeration unit is a condensing unit.

9. A cold storage, characterized in that: A refrigeration unit as described in any one of claims 6 to 8 is used.

10. A method for compensating thermal stress of a refrigeration unit according to claim 7 or 8, characterized in that: include: After the refrigeration unit is powered on and before the compressor is started, the temperature T of the gas distribution pipe connected to the first connecting member is detected; During the process from the start of the compressor to the stable operation of the compressor, the temperature Tn of the gas distribution pipe connected to the first connecting member is detected once at a preset time interval; When n is greater than or equal to 2, calculating the thermal stress of the gas distribution pipe connected to the first connecting member; The regulating component of the thermal stress compensation device is controlled accordingly according to the magnitude of the thermal stress.

11. The method for compensating thermal stress of a refrigeration unit according to claim 10, characterized in that: The thermal stress magnitude is calculated according to the formula ε = k*[T n -T n-1 +T n -T] is calculated, ε is the thermal stress, and k is the proportionality coefficient.

12. The method for compensating thermal stress of a refrigeration unit according to claim 11, characterized in that: The corresponding control of the adjustment component of the thermal stress compensation device according to the magnitude of the thermal stress includes: when the magnitude of the thermal stress is less than a first preset value, the adjustment component is not adjusted, or the adjustment component is pre-adjusted so that the gas distribution pipe connected to the first connecting member is not subjected to the tensile stress of the adjustment component.

13. The method for compensating thermal stress of a refrigeration unit according to claim 11, characterized in that: The corresponding control of the adjustment component of the thermal stress compensation device according to the thermal strain magnitude includes: when the thermal stress magnitude is greater than or equal to a first preset value and less than a second preset value, calculating the scale to be adjusted according to the thermal stress magnitude, and adjusting the adjustment component according to the readability to be adjusted.

14. The method for compensating thermal stress of a refrigeration unit according to claim 11, characterized in that: The corresponding control of the regulating component of the thermal stress compensation device according to the magnitude of the thermal stress includes: When the thermal stress is greater than or equal to a second preset value, the branch electronic expansion valve is opened to spray liquid to the suction pipe of the compressor; The opening of the electronic expansion valve is adjusted until the thermal stress value calculated most recently is smaller than the first preset value.

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