Oil way system, cascade unit, energy-saving equipment and refrigeration equipment

Abstract

The utility model relates to an oil way system, a cascade unit, energy-saving equipment and refrigeration equipment, the oil way system comprises a first heat exchanger, a first oil tank and a second oil tank, a first channel and a second channel are arranged in the first heat exchanger, and heat exchange can be conducted between the first channel and the second channel; two ends of the first oil tank are respectively communicated with the first channel to form a first circulating oil path; the two ends of the second oil tank communicate with the second channel to form a second circulating oil way. According to the oil way system, when the oil temperature in the first oil tank and the oil temperature in the second oil tank have a large temperature difference, the oil temperature of one oil tank is too low, and the oil temperature of the other oil tank is too high or too high, heat exchange between the two circulating oil ways can be achieved through the first heat exchanger; and therefore, the conditions of too low oil temperature and too high oil temperature are relieved synchronously, and normal operation of an oil way can be guaranteed. No extra heating assembly or oil cooling assembly is needed, and the power consumption and the manufacturing cost of the oil way system can be obviously reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the lubrication technical field, and particularly relates to an oil circuit system, a cascade unit, an energy-saving device and a refrigeration device. BACKGROUND

[0002] Since the lubricating oil can significantly reduce the friction between two relative motion parts, reduce wear and tear, and also take away the heat generated during the friction process through oil flow to achieve equipment cooling and prevent overheating of the equipment.

[0003] In order to realize lubrication of multiple relative friction parts, the prior art usually realizes targeted lubrication through multiple independent oil circuits. However, due to the different relative motion conditions of different friction parts, the heat generated is also quite different, which leads to a large temperature difference between multiple independent oil circuits. When the oil temperature is too low or too high, it will cause abnormal lubrication. Since multiple oil circuits are independent of each other, heat cannot be transferred and neutralized, and a one-to-one heating assembly and oil cooling assembly need to be provided for each oil circuit, which leads to an increase in the overall cost of the equipment lubrication system.

[0004] Taking the oil circuit in the cascade unit as an example, the cascade unit includes a high-temperature level refrigeration system and a low-temperature level refrigeration system. When the low-temperature level refrigeration system is started, the oil temperature of the low-temperature level lubrication system is low, the viscosity of the oil is large, and the lubricating oil has poor flowability, which will cause abnormal lubrication of the low-temperature level compressor lubrication system. The compressor in the high-temperature level refrigeration system generates a large amount of heat during operation, which will cause the temperature of the high-temperature level lubricating oil circuit to rise rapidly, the oil temperature is high, and thus the viscosity of the oil is reduced, the lubricating effect of the lubricating oil is poor, and the high-temperature level compressor lubrication system will be abnormal. Invention content

[0005] The present application provides an oil circuit system, a cascade unit, an energy-saving device and a refrigeration device to solve the technical problem that when multiple oil circuits are independent of each other in the prior art, a large temperature difference is easily generated due to different heat of the lubrication area, and the oil temperature of multiple oil circuits is easily too low or too high.

[0006] In a first aspect, the present application provides an oil circuit system, comprising:

[0007] A first heat exchanger, the inside of the first heat exchanger is provided with a first channel and a second channel, and the first channel and the second channel can exchange heat;

[0008] A first oil tank, both ends of the first oil tank are in communication with the first channel to form a first circulating oil circuit;

[0009] A second oil tank, both ends of the second oil tank are in communication with the second channel to form a second circulating oil circuit.

[0010] Optionally, the first oil tank and the second oil tank are each provided with a temperature detection member, and the first circulating oil path and the second circulating oil path are each provided with a valve member, and when the temperature difference between the oil temperature in the first oil tank and the oil temperature in the second oil tank is greater than a preset temperature difference threshold, the valve member is opened.

[0011] Optionally, the oil path system further comprises a second heat exchanger, and the two ends of the first oil tank are in communication with the second heat exchanger, forming a third circulating oil path.

[0012] Optionally, the first heat exchanger and the second heat exchanger are arranged in parallel at the two ends of the first oil tank.

[0013] Alternatively, the first heat exchanger and the second heat exchanger are arranged in series.

[0014] Optionally, the second heat exchanger is a flash evaporator provided with a heat exchange pipe group.

[0015] Optionally, the third circulating oil path is provided with a valve member.

[0016] In a second aspect, the application provides a complex superposition unit, comprising the oil path system provided by the first aspect of the application, and further comprising a high-temperature level refrigeration system, a low-temperature level refrigeration system, and an intermediate heat exchanger, the intermediate heat exchanger having a third passage and a fourth passage inside, the third passage being in communication with the high-temperature level refrigeration system to form a first refrigerant circulation loop, and the fourth passage being in communication with the low-temperature level refrigeration system to form a second refrigerant circulation loop.

[0017] The two ends of the first oil tank are in communication with the high-temperature level refrigeration system to form a fourth circulating oil path, and the two ends of the second oil tank are in communication with the low-temperature level refrigeration system to form a fifth circulating oil path.

[0018] Optionally, the high-temperature level refrigeration system comprises a first compressor and a high-temperature level condenser, a first exhaust pipe of the first compressor is in communication with the high-temperature level condenser, and the high-temperature level condenser is provided with a first oil separation assembly inside.

[0019] The fourth circulating oil path comprises a first oil supply pipe and a first oil return pipe, the first oil supply pipe is connected between the first oil tank and the first compressor, and the first oil return pipe is connected between the first oil separation assembly and the first oil tank.

[0020] Optionally, the high-temperature level refrigeration system further comprises a high-temperature level flash evaporator, a refrigerant outlet of the high-temperature level condenser is in communication with a refrigerant inlet of the high-temperature level flash evaporator through a first refrigerant inflow pipe, the high-temperature level flash evaporator is connected with a first refrigerant outflow pipe and a second refrigerant outflow pipe, the first refrigerant outflow pipe is in communication with an air inlet of the first compressor, the second refrigerant outflow pipe is in communication with an inlet of the third passage, and an outlet of the third passage is in communication with the air inlet of the first compressor.

[0021] Optionally, the low-temperature stage refrigeration system comprises a second compressor, a second exhaust pipe of the second compressor being in communication with an inlet of the fourth channel, and the intermediate heat exchanger being internally provided with a second oil separation assembly in communication with the fourth channel.

[0022] The fifth circulating oil circuit comprises a second oil supply pipe and a second oil return pipe, the second oil supply pipe being connected between the second oil tank and the second compressor, and the second oil return pipe being connected between the second oil separation assembly and the second oil tank.

[0023] Optionally, the low-temperature stage refrigeration system further comprises a low-temperature stage flash evaporator and a low-temperature stage evaporator, an outlet of the fourth channel being in communication with a refrigerant inlet of the low-temperature stage flash evaporator through a second refrigerant inflow pipe, the low-temperature stage flash evaporator being connected with a third refrigerant outflow pipe and a fourth refrigerant outflow pipe, the third refrigerant outflow pipe being in communication with an air inlet of the second compressor, and the fourth refrigerant outflow pipe being in communication with the low-temperature stage evaporator, and a refrigerant outlet of the low-temperature stage evaporator being in communication with the air inlet of the second compressor.

[0024] Optionally, the low-temperature stage flash evaporator is internally provided with a heat exchange pipe group in communication with the oil circuit of the first oil tank.

[0025] In a third aspect, the application provides an energy-saving device, comprising the cascade unit provided in the second aspect of the application, and further comprising a first working medium circulation system and a second working medium circulation system, the first working medium circulation system being connected with the high-temperature stage refrigeration system and being used for absorbing waste heat of the high-temperature stage refrigeration system, and the second working medium circulation system being connected with the low-temperature stage refrigeration system and being used for transferring waste heat to the low-temperature stage refrigeration system.

[0026] In a fourth aspect, the application further provides a refrigeration device, comprising the cascade unit provided in the second aspect of the application.

[0027] Alternatively, the refrigeration device comprises the energy-saving device provided in the third aspect of the application.

[0028] The above technical solutions provided in the embodiments of the application have the following advantages compared with the prior art:

[0029] The oil circuit system provided in the embodiment of the present application connects the first channel of the first heat exchanger to the first oil tank through the first circulation oil circuit, and connects the second channel of the first heat exchanger to the second oil tank through the second circulation oil circuit. When there is a large temperature difference between the oil temperatures in the first oil tank and the second oil tank, and one of the oil tanks has a low oil temperature and the other has an overheated or high oil temperature, the first heat exchanger can be used to achieve heat exchange between the mutually independent first circulation oil circuit and the second circulation oil circuit, thereby simultaneously alleviating the low oil temperature and overheated oil temperature conditions, thereby ensuring the normal operation of the oil circuit. There is no need to use an additional heating component to increase the temperature of an oil tank with a low oil temperature, and there is no need to use an additional oil cooling component to cool the oil in an oil tank with an overheated oil temperature, which can significantly reduce the power consumption and manufacturing cost of the oil circuit system.

[0030] The cascade unit, energy-saving equipment and refrigeration equipment provided in the embodiments of the present application include or are applied to the above-mentioned oil circuit system, and can realize oil heat exchange between the two oil tanks through the oil circuit system. Therefore, it naturally has the same technical effect as the above-mentioned oil circuit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0034] Figure 1 Schematic diagram of the energy-saving device provided in the embodiment of the present application;

[0035] Figure 2 Schematic diagram of the connection of the oil circuit system provided in the embodiment of the present application Figure 1 ;

[0036] Figure 3 A schematic diagram of the oil circuit system provided in an embodiment of the present application in an oil heat exchange mode;

[0037] Figure 4 Schematic diagram of the oil circuit system in the oil cooling mode provided in the embodiment of the present application Figure 1;

[0038] Figure 5 Connection diagram of oil circuit system provided for the embodiment of the present application Figure 2 ;

[0039] Figure 6 Connection diagram of oil circuit system provided for the embodiment of the present application in oil liquid cooling mode Figure 2 ;

[0040] Figure 7 Connection diagram of high-temperature stage refrigeration system, oil circuit system and first working medium circulation system provided for the embodiment of the present application

[0041] Figure 8 Connection diagram of low-temperature stage refrigeration system, oil circuit system and second working medium circulation system provided for the embodiment of the present application

[0042] Figure 9 Flow of control method provided for the embodiment of the present application Figure 1 ;

[0043] Figure 10 Flow of control method provided for the embodiment of the present application Figure 2 .

[0044] Explanation of reference signs:

[0045] 1, oil circuit system; 11, first heat exchanger; 12, first oil tank; 13, first circulation oil circuit; 131, first output oil circuit; 132, first input oil circuit; 133, first valve; 14, second oil tank; 15, second circulation oil circuit; 151, second output oil circuit; 152, second input oil circuit; 153, second valve; 16, third circulation oil circuit; 161, third output oil circuit; 162, third input oil circuit; 163, third valve; 164, fourth valve; 165, oil pump; 17, fourth circulation oil circuit; 171, first oil supply pipeline; 172, first oil return pipeline; 18, fifth circulation oil circuit; 181, second oil supply pipeline; 182, second oil return pipeline

[0046] 2, high-temperature stage refrigeration system; 21, first refrigerant circulation loop; 211, first exhaust pipeline; 212, first refrigerant inflow pipeline; 213, first refrigerant outflow pipeline; 214, second refrigerant outflow pipeline; 215, first intake pipeline; 216, first throttling element; 217, second throttling element; 22, first compressor; 23, high-temperature stage condenser; 24, high-temperature stage flash evaporator; 25, first dry filter

[0047] 3. Low-stage refrigeration system; 31. Second refrigerant circulation circuit; 311. Second discharge line; 312. Second refrigerant inflow line; 313. Third refrigerant outflow line; 314. Fourth refrigerant outflow line; 315. Second suction line; 316. Third throttling device; 317. Fourth throttling device; 32. Second compressor; 33. Low-stage flash evaporator; 34. Low-stage evaporator; 35. Second dry filter;

[0048] 4. Intermediate heat exchanger. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions, and superiorities of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of the present application.

[0050] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplicity, the description of a particular example will not necessarily be repeated in the description of each example. Furthermore, the present application can be implemented in a wide variety of environments and contexts. Consequently, specific details of the examples are not meant to limit the present application. In addition, the present application can repeat reference numerals and / or letters in different examples. Such repetition is expressly within the scope of the present application and does not mean that the described various embodiments and / or arrangements are related.

[0051] For the purpose of simplicity, spatial relative terms are used in the description to describe the relative position relationship or movement condition of one element or feature to another element or feature as shown in the drawings, such as "inner", "outer", "inward", "outward", "under", "below", "above", "on", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is turned over or the posture is changed or the movement condition is changed, the directional indications will also change accordingly, for example: the element described as "under" or "below" another element or feature will be oriented as "above" or "over" the other element or feature. Therefore, the example term "below" can include both upward and downward positions. The device can be additionally oriented (rotated 90 degrees or in other directions) and the spatial relative relationship descriptors used in the description are interpreted accordingly.

[0052] To solve the technical problem that when multiple oil circuits are independent of each other, a large temperature difference is easily generated due to different heat of lubrication areas, and the multiple oil circuits are easily in a situation of too low or too high oil temperature, the application provides an oil circuit system 1, a cascade unit, an energy-saving device and a refrigeration device, which can realize heat exchange between two circulating oil circuits through a first heat exchanger 11, and when a large temperature difference exists between two independent oil circuits, the temperature difference between the two oil circuits can be reduced through heat exchange, thereby avoiding the situation that the two oil circuits are respectively in a too low or too high temperature, and normal operation of the oil circuit can be ensured.

[0053] Referring to Figures 1 to 10 , the first aspect of the embodiment of the application provides an oil circuit system 1, comprising a first heat exchanger 11, a first oil tank 12 and a second oil tank 14, the first heat exchanger 11 is internally provided with a first channel and a second channel, and heat exchange can be performed between the first channel and the second channel. Specifically, the first heat exchanger 11 can be a plate heat exchanger, a tube-in-tube heat exchanger or the like, and the first channel and the second channel can be in a structure form of being wound around each other or nested, which can all achieve the purpose of the application.

[0054] Referring to Figure 1 and Figure 2 , the two ends of the first oil tank 12 are respectively communicated with the first channel, forming a first circulating oil circuit 13, and the oil in the first oil tank 12 enters the first channel to exchange heat and then flows back to the first oil tank 12, so that the temperature change of the oil in the first circulating oil circuit 13 and the first oil tank 12 can be realized. The two ends of the second oil tank 14 are respectively communicated with the second channel, forming a second circulating oil circuit 15, and the oil in the second oil tank 14 enters the second channel to exchange heat and then flows back to the second oil tank 14, so that the temperature change of the oil in the second circulating oil circuit 15 and the second oil tank 14 can be realized. When a large temperature difference exists between the oil in the first oil tank 12 and the oil in the second oil tank 14, and one of them is in a situation of too low oil temperature and the other is in a situation of too high oil temperature, heat exchange between the two circulating oil circuits can be realized through the first heat exchanger 11, and then the situations of too low oil temperature and too high oil temperature can be simultaneously relieved, without the need of an additional heating component to increase the temperature of the oil tank with too low oil temperature, and without the need of an additional oil cooling component to cool the oil in the oil tank with too high oil temperature, which can significantly reduce the power consumption and manufacturing cost of the oil circuit system 1.

[0055] It should be noted that when one of the first oil tank 12 and the second oil tank 14 is in a situation of too low oil temperature, and the other is only in a situation of relatively high oil temperature (i.e. not in a situation of too high oil temperature), heat exchange between the two circulating oil circuits can still be realized through the first heat exchanger 11, and while avoiding the situation of too low oil temperature in one of them, the oil in the other oil tank can be cooled to improve the cooling capacity of the oil after cooling.

[0056] In some embodiments of the present application, please refer to Figure 1 , Figure 2 and Figure 5 , the arrows in the figure represent the direction of oil flow, in the first heat exchanger 11, the flow direction of the oil in the first channel and the oil in the second channel is opposite, by means of counter-flow heat exchange, the heat exchange path of the oil of different temperatures in the first heat exchanger 11 is prolonged, which can improve the heat exchange efficiency of the hot oil and the cold oil in the first heat exchanger 11, so that the temperature distribution in the first heat exchanger 11 is relatively uniform, which helps to reduce the thermal stress caused by temperature gradient and improve the stability and life of the first heat exchanger 11.

[0057] In some embodiments of the present application, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 5 , the first circulating oil circuit 13 includes a first output oil circuit 131 and a first input oil circuit 132, the first output oil circuit 131 is used for outputting the oil in the first oil tank 12 to the first channel of the first heat exchanger 11; the first input oil circuit 132 is used for inputting the oil in the first channel to the first oil tank 12 to realize the backflow of the oil after heat exchange. The second circulating oil circuit 15 includes a second output oil circuit 151 and a second input oil circuit 152, the second output oil circuit 151 is used for outputting the oil in the second oil tank 14 to the second channel of the first heat exchanger 11; the second input oil circuit 152 is used for inputting the oil in the second channel to the second oil tank 14 to realize the backflow of the oil after heat exchange.

[0058] In some embodiments of the present application, temperature detection members are arranged in the first oil tank 12 and the second oil tank 14, and valve members are arranged on the first circulating oil circuit 13 and the second circulating oil circuit 15, when the difference between the oil temperature in the first oil tank 12 and the oil temperature in the second oil tank 14 is greater than a preset temperature difference threshold, the valve members are opened, which can ensure the effectiveness of the temperature neutralization of the oil in the two tanks through heat exchange. Specifically, if the oil temperature difference between the first oil tank 12 and the second oil tank 14 is large, after heat exchange through the first heat exchanger 11, the oil temperature of the two tanks can change greatly (the low-temperature oil is heated and the high-temperature oil is cooled), which can ensure the effect of avoiding low temperature and overheating of the oil through heat exchange. If the oil temperature difference between the first oil tank 12 and the second oil tank 14 is small (both of them have low-temperature oil or high-temperature oil), after heat exchange through the first heat exchanger 11, the oil temperature of the two tanks will not change greatly, but will still maintain the original oil temperature level, which cannot effectively alleviate the low-temperature oil or high-temperature oil.

[0059] It should be noted that the temperature difference preset threshold can be set according to actual conditions, and in some preferred embodiments of the present application, the temperature difference preset threshold has a value range of 20℃ or more.

[0060] In the following embodiments of the present application, it will be described that the oil temperature in the first oil tank 12 is higher than the oil temperature in the second oil tank 14. When the oil in the second oil tank 14 has a problem of being too low in temperature and poor in flowability, since the oil in the first oil tank 12 has a higher temperature, the oil in the first oil tank 12 can exchange heat with the oil in the second oil tank 14 through the first heat exchanger 11, so that the oil flowing back to the first oil tank 12 from the first heat exchanger 11 is cooled, and the oil flowing back to the second oil tank 14 from the first heat exchanger 11 is heated, which is beneficial to guarantee the normal operation of the lubrication systems corresponding to the first oil tank 12 and the second oil tank 14 respectively.

[0061] It should be noted that in the heat exchange process, the oils in the first oil tank 12 and the second oil tank 14 will not be mixed, and the quality of the oils in the first oil tank 12 and the second oil tank 14 will not be adversely affected. The first oil tank 12 and the second oil tank 14 can select lubricating oils of different brands according to the lubrication needs, which will not affect the normal operation of the lubrication system.

[0062] In the above embodiments, if the oil temperature in the first oil tank 12 is too high after heat exchange with the oil in the second oil tank 14, or the oil temperature in the second oil tank 14 is within the normal working temperature range and cannot cool the oil in the first oil tank 12, the oil in the first oil tank 12 will be at risk of overheating, and the oil in the first oil tank 12 needs to be further cooled.

[0063] To solve the above technical problems, in some embodiments of the present application, referring to Figure 2 and Figure 5 , the oil circuit system 1 further comprises a second heat exchanger, the two ends of the first oil tank 12 are respectively communicated with the second heat exchanger, forming a third circulating oil circuit 16, and the oil in the first oil tank 12 can exchange heat in the second heat exchanger, so that the oil temperature in the first oil tank 12 is within the normal working temperature range.

[0064] Specifically, in the second heat exchanger, the oil in the first oil tank 12 can exchange heat with other working medium, so that the oil temperature in the first oil tank 12 is reduced, avoiding the risk of overheating of the oil in the first oil tank 12. The normal working temperature range of the oil can be set according to the characteristics of the oil, and is usually between 10℃-50℃, and preferably between 15℃-40℃, which can not only guarantee the reasonable viscosity and good flowability of the oil, but also guarantee the good cooling effect of the oil on the lubricated parts.

[0065] In some embodiments of the present application, please refer to Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 6 , the arrow indicates the direction of oil flow, the third circulating oil path 16 includes a third output oil path 161 and a third input oil path 162, the third output oil path 161 is used to output the oil in the first oil tank 12 to the heat exchange pipe group of the second heat exchanger; the third input oil path 162 is used to input the oil in the heat exchange pipe group to the first oil tank 12, realizing the backflow of the oil after heat exchange.

[0066] In some embodiments of the present application, please refer to Figure 2 , Figure 3 and Figure 4 , the first heat exchanger 11 and the second heat exchanger are arranged in parallel at both ends of the first oil tank 12, the oil in the first oil tank 12 can pass through the first circulating oil path 13 to enter the first heat exchanger 11 and the oil in the second oil tank 14 to exchange heat, which is recorded as the oil heat exchange mode; or the oil in the first oil tank 12 can pass through the third circulating oil path 16 to enter the second heat exchanger to be cooled, which is recorded as the oil cooling mode. The oil in the first oil tank 12 can first pass through the oil heat exchange mode for the first cooling, and then pass through the oil cooling mode for the second cooling, so that the oil in the first oil tank 12 reaches a fully cooled state and is cooled to a normal working temperature range. When the temperature of the oil in the second oil tank 14 is in the normal working temperature range, the first oil tank 12 can directly enter the oil cooling mode and directly cool and cool the oil in the first oil tank 12 through the second heat exchanger.

[0067] In some other embodiments of the present application, please refer to Figure 5 and Figure 6 , the first heat exchanger 11 and the second heat exchanger are arranged in series, so that the oil in the first oil tank 12 passes through the first heat exchanger 11 and the second heat exchanger in turn (or passes through the second heat exchanger and the first heat exchanger 11 in turn), so that the oil heat exchange mode and the oil cooling mode are parallel. When the temperature of the oil in the second oil tank 14 is in the normal working temperature range, the second circulating oil path 15 can be closed, at this time the oil in the first oil tank 12 does not exchange heat with the oil in the second oil tank 14 in the first heat exchanger 11, and only the oil in the first oil tank 12 is cooled by the second heat exchanger, so that the oil cooling mode continues to operate.

[0068] As a specific embodiment of the present application, please refer to Figure 5 and Figure 6When the first heat exchanger 11 is connected in series with the second heat exchanger, the end of the first input oil line 132 is connected with the start of the third output oil line 161, so that the oil in the first oil tank 12 flows through the first heat exchanger 11 and the second heat exchanger in sequence, realizing secondary cooling, so as to reduce the temperature of the high-temperature oil in the first oil tank 12 to the normal working temperature range.

[0069] It should be noted that although the above two connection modes can realize the cooling of the oil in the first oil tank 12, when the first heat exchanger 11 is connected in series with the second heat exchanger, the oil line is relatively long, and the resistance of the oil in the flow process is also large, so the first heat exchanger 11 and the second heat exchanger are preferably connected in parallel in the embodiment of the present application.

[0070] In the above embodiment, the second heat exchanger can be any device that needs to absorb waste heat and realize utilization. By absorbing the heat of the oil in the first oil tank 12, the waste heat is recycled and utilized, and the energy utilization efficiency is improved.

[0071] In some embodiments of the present application, please refer to Figure 1 , Figure 2 and Figure 5 , the second heat exchanger is a flash evaporator provided with a heat exchange tube group, the oil in the first oil tank 12 is introduced into the heat exchange tube group as the tube-side working medium, and the refrigerant inside the flash evaporator is the shell-side working medium. The heat of the oil in the heat exchange tube group can be transferred to the shell-side working medium, so that the liquid refrigerant inside the flash evaporator can be more quickly changed from liquid to gas, improving the air charging effect of the flash evaporator and the superheat degree of air charging of the flash evaporator, avoiding damage to the compressor caused by low superheat degree of air charging of the flash evaporator.

[0072] In some embodiments of the present application, please refer to Figures 1 to 6 , the first circulating oil line 13, the second circulating oil line 15 and the third circulating oil line 16 are each provided with a valve, which can be used to realize the on-off control of the first circulating oil line 13, the second circulating oil line 15 and the third circulating oil line 16, respectively, and can be used to enter the oil heat exchange mode and / or the oil cooling mode as needed.

[0073] Specifically, the first output oil line 131 and the first input oil line 132 of the first circulating oil line 13 are each provided with a first valve 133, the second output oil line 151 and the second input oil line 152 of the second circulating oil line 15 are each provided with a second valve 153, and the third output oil line 161 and the third input oil line 162 of the third circulating oil line 16 are each provided with a third valve 163. The above-mentioned valves can be solenoid valves, electric valves, pneumatic valves and hydraulic valves, etc., which can realize the automatic on-off control of the oil line.

[0074] When the first heat exchanger 11 and the second heat exchanger are arranged in parallel, if the oil circuit system 1 needs to perform the oil heat exchange mode, the first valve 133 and the second valve 153 are opened, the first circulating oil circuit 13 and the second circulating oil circuit 15 are opened, the third valve 163 is closed, and the third circulating oil circuit 16 is closed, so that the first oil tank 12 and the second oil tank 14 can exchange heat through the first heat exchanger 11. If the oil circuit system 1 needs to perform the oil cooling mode, the first valve 133 and the second valve 153 are closed, the first circulating oil circuit 13 and the second circulating oil circuit 15 are closed, the third valve 163 is opened, and the third circulating oil circuit 16 is opened, so that the oil in the first oil tank 12 can be cooled through the second heat exchanger.

[0075] In some embodiments of the present application, the fourth valve 164 is further arranged on the first circulating oil circuit 13, the second circulating oil circuit 15 and the third circulating oil circuit 16, and the fourth valve 164 is a stop valve, so as to realize the segmented start-stop control and maintenance of each oil circuit.

[0076] In some embodiments of the present application, please refer to Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 and Figure 6 The third circulating oil circuit 16 is provided with an oil pump 165, which can provide driving force for the oil flow in the third circulating oil circuit 16. It needs to be noted that the first circulating oil circuit 13 and the second circulating oil circuit 15 can also be provided with oil pumps to provide power for the oil flow (not shown in the figure), which will not be described here.

[0077] In some embodiments of the present application, the first circulating oil circuit 13, the second circulating oil circuit 15 and the third circulating oil circuit 16 are all provided with temperature detection members, which can be used to realize the actual oil temperature detection of each part of the oil circuit system 1, so as to realize the intelligent adjustment of the oil temperature.

[0078] Please refer to Figures 1 to 10 , the second aspect of the embodiment of the present application provides a cascade unit, which comprises the oil circuit system 1 in the above embodiment, and further comprises a high-temperature level refrigeration system 2, a low-temperature level refrigeration system 3 and an intermediate heat exchanger 4. The intermediate heat exchanger 4 has a third passage and a fourth passage inside. The third passage is in communication with the high-temperature level refrigeration system 2 to form a first refrigerant circulation loop 21, and the fourth passage is in communication with the low-temperature level refrigeration system 3 to form a second refrigerant circulation loop 31. In the operation process of the cascade unit, the intermediate heat exchanger 4 is both an evaporator in the high-temperature level refrigeration system 2 and a condenser in the low-temperature level refrigeration system 3. The high-temperature level refrigeration system 2 adopts a first refrigerant with a relatively high evaporation temperature, and the low-temperature level refrigeration system 3 adopts a second refrigerant with a relatively low evaporation temperature. The second refrigerant transfers heat to the first refrigerant in the intermediate heat exchanger 4, so as to realize the condensation of the second refrigerant and the evaporation of the first refrigerant in the intermediate heat exchanger 4.

[0079] The two ends of the first oil tank 12 are respectively communicated with the high-temperature stage refrigeration system 2, forming a fourth circulating oil path 17, for providing lubricating oil liquid for the components to be lubricated in the high-temperature stage refrigeration system 2. The two ends of the second oil tank 14 are respectively communicated with the low-temperature stage refrigeration system 3, forming a fifth circulating oil path 18, for providing lubricating oil liquid for the components to be lubricated in the low-temperature stage refrigeration system 3. Since the refrigerating capacities of the high-temperature stage refrigeration system 2 and the low-temperature stage refrigeration system 3 are different, the friction heat generated in the working process is also different, which will cause a large temperature difference of the oil liquid in the first oil tank 12 and the second oil tank 14. The oil path system 1 in the above embodiment can realize the heat exchange of the oil liquid in the first oil tank 12 and the second oil tank 14, so as to make the first oil tank 12 and the second oil tank 14 respectively deliver lubricating oil in the normal working temperature range to the high-temperature stage refrigeration system 2 and the low-temperature stage refrigeration system 3, as shown in Figure 1 、 Figure 7 and Figure 8 , wherein Figure 1 、 Figure 7 and Figure 8 The dashed line pipeline in

[0080] It should be noted that in the process of operating the existing cascade unit, the following problems often exist: firstly, the lubricating oil path in the low-temperature stage refrigeration system 3 has the problem of low oil temperature at the start of the machine, the viscosity of the oil liquid is large, the flowability of the lubricating oil is poor, which will cause oil supply difficulty, and further cause the lubrication system of the compressor in the low-temperature stage refrigeration system 3 to be abnormal. Secondly, after the cascade unit is operated for a period of time, the compressor in the high-temperature stage refrigeration system 2 has a large refrigerating capacity, and the friction heat generated in the working process is also large, which will cause the oil liquid temperature to rise rapidly, the viscosity of the lubricating oil to decrease rapidly, and the lubrication effect to be poor, and further cause the lubrication system of the compressor in the high-temperature stage refrigeration system 2 to be abnormal. The oil path system 1 in the present application can realize the heat exchange of the oil liquid in the first oil tank 12 and the second oil tank 14 through the first heat exchanger 11, can avoid the oil temperature in the lubricating oil path of the compressor in the low-temperature stage refrigeration system 3 being too low, can avoid the oil temperature in the lubricating oil path of the compressor in the high-temperature stage refrigeration system 2 being too high, and further ensure the normal operation of the cascade unit.

[0081] In some embodiments of the present application, please refer to Figure 1 and Figure 7The high-temperature stage refrigeration system 2 comprises a first compressor 22 and a high-temperature stage condenser 23. A first exhaust pipe 211 of the first compressor 22 is in communication with the high-temperature stage condenser 23. During continuous exhaust of the first compressor 22, lubricating oil (i.e., refrigeration oil) will be exhausted from the first compressor 22 together with gaseous first refrigerant through the first exhaust pipe 211. If the exhausted refrigeration oil cannot be returned to the first compressor 22, the first compressor 22 will be out of oil, and in severe cases, the first compressor 22 will be damaged. Therefore, the high-temperature stage condenser 23 is internally provided with a first oil separation assembly, which can be used to separate the refrigeration oil and the first refrigerant.

[0082] The fourth circulating oil circuit 17 comprises a first oil supply pipe 171 and a first oil return pipe 172. The first oil supply pipe 171 is connected between the first oil tank 12 and the first compressor 22, and can continuously supply refrigeration oil to the first compressor 22 through the first oil tank 12. The first oil return pipe 172 is connected between the first oil separation assembly and the first oil tank 12, and can return the refrigeration oil separated in the high-temperature stage condenser 23 to the first oil tank 12, so as to realize the circulation of the refrigeration oil between the first compressor 22 and the first oil tank 12, and avoid the out-of-oil condition of the first compressor 22.

[0083] In some embodiments of the present application, referring to Figure 1 and Figure 7 The high-temperature stage refrigeration system 2 further comprises a high-temperature stage flash evaporator 24. A refrigerant outlet of the high-temperature stage condenser 23 is in communication with a refrigerant inlet of the high-temperature stage flash evaporator 24 through a first refrigerant inflow pipe 212, so as to input the condensed first refrigerant into the high-temperature stage flash evaporator 24 for rapid evaporation to form saturated gaseous refrigerant and saturated liquid refrigerant. The high-temperature stage flash evaporator 24 is connected with a first refrigerant outflow pipe 213 and a second refrigerant outflow pipe 214. The first refrigerant outflow pipe 213 is in communication with an air inlet of the first compressor 22, and the saturated gaseous refrigerant enters the high-pressure stage air inlet of the first compressor 22 from the top of the high-temperature stage flash evaporator 24, so as to be subjected to two-stage compression. The second refrigerant outflow pipe 214 is in communication with an inlet of the third channel, so as to make the saturated liquid refrigerant flow into the intermediate heat exchanger 4 for heat exchange and evaporation. An outlet of the third channel is in communication with the air inlet of the first compressor 22. The first refrigerant circulating circuit 21 comprises the first exhaust pipe 211, the first refrigerant inflow pipe 212, the first refrigerant outflow pipe 213 and the second refrigerant outflow pipe 214, and can complete the refrigerant circulation of the first refrigerant.

[0084] In some embodiments of the present application, referring to Figure 7The first refrigerant inflow pipeline 212 is provided with a first throttling device 216, which can throttle the liquid refrigerant flowing out of the high-temperature condenser, and the throttled first refrigerant can flow into the high-temperature flash evaporator 24 to be rapidly evaporated. The second refrigerant outflow pipeline 214 is provided with a second throttling device 217, which can throttle the saturated liquid refrigerant flowing out of the high-temperature flash evaporator 24, so that the saturated liquid refrigerant is further subjected to pressure reduction and expansion to become a low-pressure and low-temperature liquid, and then enters the intermediate heat exchanger 4 to be heat-exchanged and evaporated.

[0085] In some embodiments of the present application, referring to Figure 1 and Figure 7 , the first refrigerant inflow pipeline 212 is provided with a first dry filter 25, which can remove impurities and moisture in the first refrigerant, and can prolong the service life of key components (such as the first compressor 22, the first throttling device 216, the second throttling device 217, etc.) in the high-temperature refrigeration system 2.

[0086] In some embodiments of the present application, referring to Figure 1 and Figure 8 , the low-temperature refrigeration system 3 includes a second compressor 32, and a second exhaust pipeline 311 of the second compressor 32 is in communication with the inlet of the fourth channel. During continuous exhaust of the second compressor 32, the refrigeration oil in the second compressor 32 will be discharged together with the gaseous second refrigerant through the second exhaust pipeline 311. If the discharged refrigeration oil cannot return to the second compressor 32, the second compressor 32 will be out of oil or damaged. Therefore, the interior of the intermediate heat exchanger 4 is provided with a second oil separation assembly in communication with the fourth channel, which can separate the refrigeration oil and the second refrigerant.

[0087] The fifth circulating oil circuit 18 includes a second oil supply pipeline 181 and a second oil return pipeline 182. The second oil supply pipeline 181 is connected between the second oil tank 14 and the second compressor 32, and can continuously supply the refrigeration oil to the second compressor 32 through the second oil tank 14. The second oil return pipeline 182 is connected between the second oil separation assembly and the second oil tank 14, and can return the separated refrigeration oil in the intermediate heat exchanger 4 to the second oil tank 14, so as to realize the circulation of the refrigeration oil between the second compressor 32 and the second oil tank 14, and avoid the out-of-oil condition of the second compressor 32.

[0088] In some embodiments of the present application, referring to Figure 1 and Figure 8The low-temperature stage refrigeration system 3 further comprises a low-temperature stage flash evaporator 33 and a low-temperature stage evaporator 34, and the outlet of the fourth channel is communicated with the refrigerant inlet of the low-temperature stage flash evaporator 33 through a second refrigerant inflow pipeline 312, so that the condensed second refrigerant can be input into the low-temperature stage flash evaporator 33 for rapid evaporation, thereby forming saturated gaseous refrigerant and saturated liquid refrigerant. The low-temperature stage flash evaporator 33 is connected with a third refrigerant outflow pipeline 313 and a fourth refrigerant outflow pipeline 314, the third refrigerant outflow pipeline 313 is communicated with the gas inlet of the second compressor 32, and the saturated gaseous refrigerant enters the high-pressure stage gas inlet of the second compressor 32 from the top of the low-temperature stage flash evaporator 33, so that the second compression can be performed. The fourth refrigerant outflow pipeline 314 is communicated with the low-temperature stage evaporator 34, so that the saturated liquid refrigerant flows into the low-temperature stage evaporator 34 for heat exchange evaporation; the refrigerant outlet of the low-temperature stage evaporator 34 is communicated with the gas inlet of the second compressor 32, and the second refrigerant circulation loop 31 comprises the second exhaust pipeline 311, the second refrigerant inflow pipeline 312, the third refrigerant outflow pipeline 313 and the fourth refrigerant outflow pipeline 314, so that the refrigerant circulation of the second refrigerant can be completed.

[0089] In the above embodiment, because the evaporation temperature of the second refrigerant is low, the gaseous second refrigerant output by the low-temperature stage flash evaporator 33 is lower than the saturation temperature at the pressure, thereby causing the low-temperature stage flash evaporator 33 to have a low superheat degree of the gas supplement, which may cause the second refrigerant to be liquefied in the second compressor 32 and cause damage to the second compressor 32.

[0090] To solve the above problem, in some embodiments of the present application, a heat exchange pipe group is arranged in the low-temperature stage flash evaporator 33, and the heat exchange pipe group is communicated with the oil circuit of the first oil tank 12, so that the low-temperature stage flash evaporator 33 can be configured as a second heat exchanger in the oil circuit system 1, thereby reducing the temperature of the oil liquid in the first oil tank 12, and improving the temperature of the gaseous second refrigerant input into the second compressor 32 by the low-temperature stage flash evaporator 33, thereby improving the superheat degree of the low-temperature stage flash evaporator 33.

[0091] In some embodiments of the present application, a baffle plate is further arranged in the liquid storage area in the low-temperature stage flash evaporator 33, which can strengthen the disturbance of the second refrigerant for rapid evaporation, and can also prevent the liquid refrigerant in the low-temperature stage flash evaporator 33 from being carried into the second compressor 32 during the gas flow, thereby improving the superheat degree of the low-temperature flash evaporator.

[0092] In some embodiments of the present application, please refer to Figure 8The second refrigerant inflow pipeline 312 is provided with a third throttling device 316, and the fourth refrigerant outflow pipeline 314 is provided with a fourth throttling device 317. The second refrigerant inflow pipeline 312 is provided with a second drying filter 35, which can throttle or dry filter the second refrigerant in the second refrigerant circulation loop 31, and the effect is similar to the first throttling device 216, the second throttling device 217 and the first drying filter 25, which will not be described here.

[0093] In the above embodiment, the first compressor 22 and the second compressor 32 are screw compressors, which can realize stepless adjustment of energy, so that the cascade unit can flexibly adjust the refrigerating capacity according to the actual demand during operation, thereby improving the operation efficiency.

[0094] Please refer to Figures 1 to 10 The third aspect of the embodiment of the present application provides an energy-saving device, which comprises the cascade unit in the above embodiment, and further comprises a first working medium circulation system and a second working medium circulation system. The first working medium circulation system is connected with the high-temperature-level refrigeration system 2, is used for absorbing the waste heat of the high-temperature-level refrigeration system 2, and realizes temperature rise of the first working medium in the first working medium circulation system through the waste heat of the high-temperature-level refrigeration system 2, so as to realize supply of hot fluid. The second working medium circulation system is connected with the low-temperature-level refrigeration system 3, is used for transferring waste heat to the low-temperature-level refrigeration system 3, realizes temperature drop of the second working medium in the second working medium circulation system, and thus realizes supply of cold fluid.

[0095] In the above embodiment, the first working medium and the second working medium can be water, lubricating oil and refrigerant, etc., which can realize efficient use of energy through heat exchange, so as to reduce energy consumption caused by temperature rise or cooling of the working medium, and achieve energy-saving effect.

[0096] As a specific embodiment of the present application, the first working medium circulation system is a cooling water circulation system, and the second working medium circulation system is a chilled water circulation system. The cooling water circulation system exchanges heat with the high-temperature-level refrigeration system 2 through the high-temperature-level condenser 23, can absorb the waste heat of the high-temperature-level refrigeration system 2, and makes the first refrigerant condense in the high-temperature-level condenser 23. The cooling water flowing out of the high-temperature-level condenser 23 can be used as hot water supply. The chilled water circulation system exchanges heat with the low-temperature-level refrigeration system 3 through the low-temperature-level evaporator 34, can transfer waste heat to the low-temperature-level refrigeration system 3, and makes the second refrigerant evaporate in the low-temperature-level evaporator 34. The chilled water realizes temperature drop inside the low-temperature-level evaporator 34, so that the chilled water flowing out of the low-temperature-level evaporator 34 can be used as cooling working medium in the cooling circulation system.

[0097] Please refer to Figures 1 to 10 The fourth aspect of the embodiment of the present application provides a refrigeration device, which comprises the cascade unit in the above embodiment, such as air conditioner and refrigerator, etc., can realize partition refrigeration (or heating), and is used for meeting temperature demand of different areas.

[0098] In some embodiments of the present application, the refrigeration device comprises the energy-saving device in the above-mentioned embodiments, and can realize the synchronous supply of the hot fluid and the cooling working medium while realizing the refrigeration and heating requirements, thereby reducing the overall energy consumption of the refrigeration device.

[0099] Referring to Figures 1 to 10 The fifth aspect of the embodiments of the present application provides a control method applied to the oil circuit system 1 in the above-mentioned embodiments, comprising the following steps:

[0100] Step one: starting the cascade unit;

[0101] Step two: obtaining the actual oil temperature value T1 in the first oil tank 12 and the actual oil temperature value T2 in the second oil tank 14; and determining whether to enter the oil heat exchange mode or the oil cooling mode according to the comparison between the actual oil temperature value and the preset oil temperature threshold value.

[0102] Since the flowability of the compressor refrigeration oil is poor when the oil temperature is too low, and the lubrication effect of the oil is poor when the oil temperature is too high, the preset oil temperature threshold value comprises a first oil temperature threshold value Y1 and a second oil temperature threshold value Y2, and Y1>Y2; wherein Y1 is the minimum limit value of the oil temperature, and the flowability of the oil is poor when the oil temperature is lower than the first oil temperature threshold value Y1; Y2 is the maximum limit value of the oil temperature, and the lubrication effect of the oil is poor when the oil temperature is higher than the second oil temperature threshold value Y2.

[0103] As a specific embodiment of the present application, the value of the first oil temperature threshold value Y1 is 10°C, and the value of the second oil temperature threshold value Y2 is 50°C.

[0104] Step three: determining whether T2 is less than the second oil temperature threshold value Y2, so as to confirm whether the lubricating oil circuit of the low-temperature stage refrigeration system 3 has the risk of poor flowability; if T1>Y2>T2, the first valve 133 and the second valve 153 are opened, the first circulating oil circuit 13 and the second circulating oil circuit 15 are opened, and the oil heat exchange mode is entered; since the refrigeration capacity of the first compressor 22 is greater than that of the second compressor 32, the oil temperature in the first oil tank 12 can be rapidly increased, and when the first oil tank 12 and the second oil tank 14 exchange heat through the first heat exchanger 11, the temperature of the oil in the second oil tank 14 can be increased, so that the temperature of the oil in the second oil tank 14 is increased to the normal working temperature range, and at the same time, the rising speed of the oil temperature in the first oil tank 12 is slowed down, so as to avoid the over-high oil temperature in the first oil tank 12, thereby avoiding the over-high oil temperature entering the first compressor 22.

[0105] It should be noted that in the initial stage of starting the cascade unit, if the oil temperature in the first oil tank 12 is also low, the oil in the second oil tank 14 can be first heated by other heating methods, such asFigure 9 as shown.

[0106] Step four: after the cascade unit runs for a period of time, if the oil temperature in the second oil tank 14 reaches T2≥Y2, the first valve 133 and the second valve 153 are closed, and the first circulating oil circuit 13 and the second circulating oil circuit 15 are closed.

[0107] Step five: please refer to Figure 10 After the cascade unit runs for a long time, the oil temperature in the first oil tank 12 continues to rise, and the oil in the first oil tank 12 is at risk of overheating. It is determined whether T1 is greater than the first oil temperature threshold Y1. If T1≥Y1 and T2≥Y2, the third valve 163 is opened, the third circulating oil circuit 16 is opened, and the oil liquid cooling mode is entered. The oil liquid output from the first oil tank 12 exchanges heat inside the low-temperature stage flasher 33 in the cascade unit, so that the oil liquid temperature is transferred to the refrigerant in the low-temperature stage flasher 33. Not only can the oil liquid in the first oil tank 12 be cooled, but also the superheat degree of the low-temperature stage flasher 33 can be improved.

[0108] Step six: when the oil temperature in the first oil tank 12 is reduced to the normal working temperature range, the third valve 163 is closed, and the third circulating oil circuit 16 is closed. (If the first heat exchanger 11 and the second heat exchanger are in series, the first valve 133 and the first circulating oil circuit 13 also need to be closed.)

[0109] It should be understood that the terms used herein are for the purpose of describing particular example embodiments and are not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically indicated as such. It is also to be understood that additional or alternative steps can be employed.

[0110] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example implementations.

[0111] The foregoing detailed description of the application has been presented for purposes of illustration and description. Various modifications and changes can be made to the embodiments in light of the above detailed description without departing from the spirit and intended scope of the application. It is to be understood that the application can be practiced without the following claims.

Claims

1. An oil circuit system (1), characterized in that: include: A first heat exchanger (11), wherein a first channel and a second channel are provided inside the first heat exchanger (11), and heat exchange can be performed between the first channel and the second channel; a first oil tank (12), wherein both ends of the first oil tank (12) are respectively connected to the first channel to form a first circulating oil circuit (13); A second oil tank (14), both ends of which are respectively connected to the second channel to form a second circulating oil circuit (15).

2. The oil circuit system (1) according to claim 1, characterized in that: The first oil tank (12) and the second oil tank (14) are both provided with temperature detection components, and the first circulating oil circuit (13) and the second circulating oil circuit (15) are respectively provided with valve components, and the valve components are opened when the difference between the oil temperature in the first oil tank (12) and the oil temperature in the second oil tank (14) is greater than a preset temperature difference threshold.

3. The oil circuit system (1) according to claim 1 or 2, characterized in that: It also includes a second heat exchanger, and both ends of the first oil tank (12) are respectively connected to the second heat exchanger to form a third circulating oil circuit (16).

4. The oil circuit system (1) according to claim 3, characterized in that: The first heat exchanger (11) and the second heat exchanger are arranged in parallel at both ends of the first oil tank (12); Alternatively, the first heat exchanger (11) and the second heat exchanger are arranged in series.

5. The oil circuit system (1) according to claim 3, characterized in that: The second heat exchanger is a flash heat exchanger provided with a heat exchange tube group.

6. The oil circuit system (1) according to claim 3, characterized in that: The third circulating oil circuit (16) is provided with a valve.

7. A cascade unit, characterized in that: The oil circuit system (1) comprises the oil circuit system (1) according to any one of claims 1 to 6, and further comprises a high-temperature refrigeration system (2), a low-temperature refrigeration system (3) and an intermediate heat exchanger (4), wherein the intermediate heat exchanger (4) has a third channel and a fourth channel inside, the third channel is connected to the high-temperature refrigeration system (2) to form a first refrigerant circulation loop (21), and the fourth channel is connected to the low-temperature refrigeration system (3) to form a second refrigerant circulation loop (31); The two ends of the first oil tank (12) are respectively connected to the high-temperature refrigeration system (2) to form a fourth circulating oil circuit (17), and the two ends of the second oil tank (14) are respectively connected to the low-temperature refrigeration system (3) to form a fifth circulating oil circuit (18).

8. The cascade unit according to claim 7, characterized in that: The high-temperature refrigeration system (2) comprises a first compressor (22) and a high-temperature condenser (23); a first exhaust pipe (211) of the first compressor (22) is in communication with the high-temperature condenser (23); and a first oil separation assembly is provided inside the high-temperature condenser (23); The fourth circulating oil circuit (17) comprises a first oil supply pipeline (171) and a first oil return pipeline (172), wherein the first oil supply pipeline (171) is connected between the first oil tank (12) and the first compressor (22), and the first oil return pipeline (172) is connected between the first oil separation assembly and the first oil tank (12).

9. The cascade unit according to claim 8, characterized in that: The high-temperature refrigeration system (2) further includes a high-temperature flasher (24), the refrigerant outlet of the high-temperature condenser (23) and the refrigerant inlet of the high-temperature flasher (24) are connected via a first refrigerant inlet pipe (212), the high-temperature flasher (24) is connected to a first refrigerant outflow pipe (213) and a second refrigerant outflow pipe (214), the first refrigerant outflow pipe (213) is connected to the air inlet of the first compressor (22), the second refrigerant outflow pipe (214) is connected to the inlet of the third channel, and the outlet of the third channel is connected to the air inlet of the first compressor (22).

10. The cascade unit according to any one of claims 7 to 9, characterized in that: The low-temperature refrigeration system (3) includes a second compressor (32), a second exhaust pipe (311) of the second compressor (32) is connected to the inlet of the fourth channel, and a second oil separation component connected to the fourth channel is provided inside the intermediate heat exchanger (4); The fifth circulating oil circuit (18) comprises a second oil supply pipeline (181) and a second oil return pipeline (182), wherein the second oil supply pipeline (181) is connected between the second oil tank (14) and the second compressor (32), and the second oil return pipeline (182) is connected between the second oil separation assembly and the second oil tank (14).

11. The cascade unit according to claim 10, characterized in that: The low-temperature refrigeration system (3) also includes a low-temperature flasher (33) and a low-temperature evaporator (34), the outlet of the fourth channel is connected to the refrigerant inlet of the low-temperature flasher (33) through a second refrigerant inlet pipe (312), the low-temperature flasher (33) is connected to a third refrigerant outflow pipe (313) and a fourth refrigerant outflow pipe (314), the third refrigerant outflow pipe (313) is connected to the air inlet of the second compressor (32), the fourth refrigerant outflow pipe (314) is connected to the low-temperature evaporator (34), and the refrigerant outlet of the low-temperature evaporator (34) is connected to the air inlet of the second compressor (32).

12. The cascade unit according to claim 11, characterized in that: A heat exchange tube group is provided inside the low-temperature flasher (33), and the heat exchange tube group is connected to the oil circuit of the first oil tank (12).

13. An energy-saving device, characterized in that: A cascade unit comprising the cascade unit according to any one of claims 7 to 12, further comprising a first working fluid circulation system and a second working fluid circulation system, wherein the first working fluid circulation system is connected to the high-temperature refrigeration system (2) and is used to absorb waste heat of the high-temperature refrigeration system (2); The second working medium circulation system is connected to the low-temperature refrigeration system (3) and is used to transfer waste heat to the low-temperature refrigeration system (3).

14. A refrigeration device, characterized in that: comprising the cascade unit according to any one of claims 7 to 12; Alternatively, it includes the energy-saving device as claimed in claim 13.

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