Cascade Refrigeration Equipment

Abstract

This application relates to a cascade refrigeration device. The refrigeration device includes: a high-temperature refrigerant flow path, the input end of which is connected to the first output end of an evaporator-condenser, and the output end of which is connected to the first input end of the evaporator-condenser; the high-temperature refrigerant flow path is used to pre-cool the low-temperature refrigerant flow path; a low-temperature refrigerant flow path, the input end of which is connected to the second output end of the evaporator-condenser, and the output end of which is connected to the second input end of the evaporator-condenser; the low-temperature refrigerant flow path is used to cool the refrigeration device; and an evaporator-condenser is used to exchange the heat generated by the high-temperature and low-temperature refrigerant flow paths. This application solves the technical problem of low operating efficiency in existing low-temperature refrigeration technologies when obtaining low-temperature environments.

Description

Technical Field

[0001] This application relates to the field of refrigeration equipment technology, and in particular to a cascade refrigeration device. Background Technology

[0002] With the development of science and technology and the improvement of living standards, cryogenic refrigeration technology is being used more and more widely in medical and health care, food storage and other fields. To obtain a low-temperature environment, single-stage or two-stage vapor compression refrigeration systems are usually used, but these are difficult to implement and have low operating efficiency. Summary of the Invention

[0003] This application provides a cascade refrigeration device to solve the technical problem of low operating efficiency of existing cryogenic refrigeration technologies when obtaining low-temperature environments.

[0004] This application provides a cascade refrigeration device, comprising: a high-temperature refrigerant flow path, wherein the input end of the high-temperature refrigerant flow path is connected to a first output end of an evaporator-condenser, and the output end of the high-temperature refrigerant flow path is connected to a first input end of the evaporator-condenser, and the high-temperature refrigerant flow path is used to pre-cool a low-temperature refrigerant flow path; a low-temperature refrigerant flow path, wherein the input end of the low-temperature refrigerant flow path is connected to a second output end of the evaporator-condenser, and the output end of the low-temperature refrigerant flow path is connected to a second input end of the evaporator-condenser, and the low-temperature refrigerant flow path is used to cool the refrigeration device; and the evaporator-condenser is used to exchange the heat generated by the high-temperature refrigerant flow path and the low-temperature refrigerant flow path.

[0005] As an optional example, the aforementioned high-temperature refrigerant flow path includes: a gas-liquid separator, the first end of which is connected to the first output end of the evaporator-condenser, and the second end of which is connected to the first end of the high-temperature compressor, the gas-liquid separator being used to store the liquid refrigerant discharged from the evaporator-condenser; the high-temperature compressor, the second end of which is connected to the first end of an anti-condensation tube; the anti-condensation tube, the second end of which is connected to the first end of the high-temperature condenser, the anti-condensation tube being used to heat the door seal of the refrigeration equipment; the high-temperature condenser, the second end of which is connected to the first end of a high-temperature filter; the high-temperature filter, the second end of which is connected to the first end of a high-temperature capillary tube; and the high-temperature capillary tube, the second end of which is connected to the first input end of the evaporator-condenser.

[0006] As an optional example, the aforementioned low-temperature refrigerant flow path includes: a low-temperature filter, the first end of which is connected to the second output end of the aforementioned evaporator-condenser, and the second end of which is connected to the first end of the low-temperature capillary; the low-temperature capillary, the second end of which is connected to the first end of the evaporator; the evaporator, the second end of which is connected to the first end of the low-temperature compressor; the low-temperature compressor, the second end of which is connected to the first end of the oil separator; and the oil separator, the second end of which is connected to the second input end of the aforementioned evaporator-condenser.

[0007] As an optional example, the aforementioned low-temperature refrigerant flow path further includes: a first solenoid valve, the first end of which is connected to the second input end of the evaporator-condenser, and the second end of which is connected to the first end of a second solenoid valve; a second solenoid valve, the second end of which is connected to the second end of the evaporator; a third solenoid valve, the first end of which is connected to the second end of the evaporator, and the second end of which is connected to the first end of a fourth solenoid valve; a fourth solenoid valve, the second end of which is connected to the first end of the evaporator; a cold accumulator, the first end of which is connected to the first end of the fourth solenoid valve, and the second end of which is connected to the first end of an air pump; and an air pump, the second end of which is connected to the second end of the first solenoid valve.

[0008] As an optional example, the high-temperature refrigerant flow path is also used to pre-cool the low-temperature refrigerant flow path when the refrigeration equipment is started, wherein the high-temperature compressor starts at a first frequency and rises to a second frequency at a first rate.

[0009] As an optional example, the aforementioned low-temperature refrigerant flow path is also used to open the air pump, the first solenoid valve, and the third solenoid valve when the frequency of the aforementioned high-temperature compressor reaches the aforementioned second frequency, so that the aforementioned high-temperature refrigerant flow path pre-cools the aforementioned low-temperature refrigerant flow path.

[0010] As an optional example, the aforementioned low-temperature refrigerant flow path is also used to close the aforementioned air pump, the aforementioned first solenoid valve, and the aforementioned third solenoid valve when the discharge pressure of the low-temperature compressor is within a preset pressure range. The aforementioned low-temperature compressor starts at a third frequency and rises to a fourth frequency at a second rate to cool the aforementioned refrigeration equipment, wherein the aforementioned fourth frequency is greater than the aforementioned third frequency.

[0011] As an optional example, the aforementioned low-temperature refrigerant flow path is also used to open the aforementioned air pump, second solenoid valve, and fourth solenoid valve to cool the cold storage unit when the evaporator temperature is lower than the first preset temperature.

[0012] As an optional example, the aforementioned low-temperature refrigerant flow path is also used to close the aforementioned air pump, the aforementioned second solenoid valve, and the aforementioned fourth solenoid valve when the aforementioned evaporation temperature is higher than the second preset temperature, so as to transfer the cold energy in the aforementioned cold storage to the aforementioned evaporator and reduce the aforementioned evaporation temperature, wherein the aforementioned second preset temperature is greater than the aforementioned first preset temperature.

[0013] As an optional example, the aforementioned low-temperature refrigerant flow path is also used to open the aforementioned air pump, the aforementioned second solenoid valve, and the aforementioned fourth solenoid valve in the event of a failure and shutdown of the aforementioned low-temperature compressor, so as to transfer the cold energy in the aforementioned cold accumulator to the evaporator.

[0014] In this embodiment, a high-temperature refrigerant flow path is employed. The input end of the high-temperature refrigerant flow path is connected to the first output end of the evaporator-condenser, and the output end of the high-temperature refrigerant flow path is connected to the first input end of the evaporator-condenser. This high-temperature refrigerant flow path is used to pre-cool the low-temperature refrigerant flow path. The input end of the low-temperature refrigerant flow path is connected to the second output end of the evaporator-condenser, and the output end of the low-temperature refrigerant flow path is connected to the second input end of the evaporator-condenser. This low-temperature refrigerant flow path is used to cool the refrigeration equipment. The evaporator-condenser is used for exchanging the upper... The refrigeration equipment that generates heat from the high-temperature refrigerant flow path and the low-temperature refrigerant flow path employs a cascade refrigeration system, comprising a high-temperature refrigerant flow path and a low-temperature refrigerant flow path. Heat exchange between the two flow paths occurs via an evaporator-condenser. The high-temperature refrigerant flow path is activated first to pre-cool the low-temperature refrigerant flow path, and then the low-temperature refrigerant flow path is activated to cool the refrigeration equipment. This achieves rapid cooling of the low-temperature refrigerant, improving operating efficiency and solving the technical problem of low operating efficiency in existing low-temperature refrigeration technologies when operating in low-temperature environments. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0018] Figure 1 This is a schematic diagram of an optional cascade refrigeration device according to an embodiment of this application;

[0019] Figure 2 This is a circuit diagram of an optional cascade refrigeration device according to an embodiment of this application;

[0020] Figure 3 This is a control flowchart of an optional cascade refrigeration device according to an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0023] This application provides a cascade refrigeration device, optionally, such as Figure 1 As shown, the above-mentioned refrigeration equipment includes:

[0024] The high-temperature refrigerant flow path 102 has its input end connected to the first output end of the evaporator-condenser and its output end connected to the first input end of the evaporator-condenser. The high-temperature refrigerant flow path is used to pre-cool the low-temperature refrigerant flow path.

[0025] The low-temperature refrigerant flow path 104 has its input end connected to the second output end of the evaporator-condenser and its output end connected to the second input end of the evaporator-condenser. The low-temperature refrigerant flow path is used to refrigerate refrigeration equipment.

[0026] Evaporator-condenser 106 is used to exchange the heat generated by the high-temperature refrigerant flow path and the low-temperature refrigerant flow path.

[0027] Optionally, with the development of science and technology and the improvement of living standards, cryogenic refrigeration technology is increasingly widely used in medical and health care, food storage, and other fields. To obtain a low-temperature environment, single-stage or two-stage vapor compression refrigeration systems are typically used, but these are difficult to implement and have low operating efficiency. Therefore, in this embodiment, a cascade refrigeration system is adopted, comprising a high-temperature stage refrigerant flow path and a low-temperature stage refrigerant flow path. The input end of the high-temperature stage refrigerant flow path is connected to the first output end of the evaporator-condenser, and the output end of the high-temperature stage refrigerant flow path is connected to the first input end of the evaporator-condenser. The input end of the low-temperature stage refrigerant flow path is connected to the second output end of the evaporator-condenser, and the output end of the low-temperature stage refrigerant flow path is connected to the second input end of the evaporator-condenser. Furthermore, the heat exchange between the high-temperature refrigerant flow path and the low-temperature refrigerant flow path is carried out through an evaporator-condenser. The high-temperature refrigerant flow path is started first to pre-cool the low-temperature refrigerant flow path, and then the low-temperature refrigerant flow path is started to cool the refrigeration equipment. This achieves the goal of rapid cooling of the low-temperature refrigerant and improving operating efficiency, thereby solving the technical problem of low operating efficiency of existing low-temperature refrigeration technology when obtaining low-temperature environments.

[0028] As an alternative example, the high-temperature refrigerant flow path includes:

[0029] The gas-liquid separator has its first end connected to the first output end of the evaporator-condenser, and its second end connected to the first end of the high-temperature stage compressor. The gas-liquid separator is used to store the liquid refrigerant discharged from the evaporator-condenser.

[0030] The high-temperature stage compressor has its second end connected to the first end of the anti-condensation pipe.

[0031] The anti-condensation tube has its second end connected to the first end of the high-temperature condenser. The anti-condensation tube is used to heat the door seal of the refrigeration equipment.

[0032] A high-temperature stage condenser, the second end of which is connected to the first end of a high-temperature stage filter;

[0033] A high-temperature filter, the second end of which is connected to the first end of a high-temperature capillary.

[0034] The high-temperature capillary tube has its second end connected to the first input end of the evaporator-condenser.

[0035] Optionally, in this embodiment, the high-temperature refrigerant flow path consists of a gas-liquid separator, a high-temperature compressor, an anti-condensation tube, a high-temperature condenser, a high-temperature filter, and a high-temperature capillary tube. The first end of the liquid separator is connected to the first output end of the evaporator-condenser; the second end of the gas-liquid separator is connected to the first end of the high-temperature compressor; the second end of the high-temperature compressor is connected to the first end of the anti-condensation tube; the second end of the anti-condensation tube is connected to the first end of the high-temperature condenser; the second end of the high-temperature condenser is connected to the first end of the high-temperature filter; the second end of the high-temperature filter is connected to the first end of the high-temperature capillary tube; and the second end of the high-temperature capillary tube is connected to the first input end of the evaporator-condenser. The gas-liquid separator stores the liquid refrigerant at the outlet of the evaporator-condenser to prevent wet compression, which could cause liquid slugging in the high-temperature compressor and shorten its lifespan. The anti-condensation tube is encapsulated at the door seal of the refrigeration equipment, serving to heat the door seal and reduce condensation and frost formation.

[0036] As an optional example, the cryogenic refrigerant flow path includes:

[0037] The first end of the low-temperature filter is connected to the second output end of the evaporator-condenser, and the second end of the low-temperature filter is connected to the first end of the low-temperature capillary.

[0038] The low-temperature stage capillary tube is connected at its second end to the first end of the evaporator.

[0039] The evaporator, with its second end connected to the first end of the low-temperature stage compressor;

[0040] The cryogenic stage compressor has its second end connected to the first end of the oil separator.

[0041] The oil separator has its second end connected to the second input end of the evaporator-condenser.

[0042] Optionally, in this embodiment, the low-temperature refrigerant flow path consists of a low-temperature filter, a low-temperature capillary tube, an evaporator, a low-temperature compressor, and an oil separator. The first end of the low-temperature filter is connected to the second output end of the evaporator-condenser, the second end of the low-temperature filter is connected to the first end of the low-temperature capillary tube, the second end of the low-temperature capillary tube is connected to the first end of the evaporator, the second end of the evaporator is connected to the first end of the low-temperature compressor, the second end of the low-temperature compressor is connected to the first end of the oil separator, the second end of the oil separator is connected to the second input end of the evaporator-condenser, and an oil return line is provided between the low-temperature compressor and the oil separator.

[0043] As an optional example, the cryogenic refrigerant flow path also includes:

[0044] The first solenoid valve has its first end connected to the second input end of the evaporator-condenser, and its second end connected to the first end of the second solenoid valve.

[0045] The second solenoid valve, the second end of the second solenoid valve is connected to the second end of the evaporator;

[0046] The third solenoid valve has its first end connected to the second end of the evaporator, and its second end is connected to the first end of the fourth solenoid valve.

[0047] The fourth solenoid valve, the second end of which is connected to the first end of the evaporator;

[0048] The cold accumulator has its first end connected to the first end of the fourth solenoid valve and its second end connected to the first end of the air pump.

[0049] An air pump, the second end of which is connected to the second end of the first solenoid valve.

[0050] Optionally, in this embodiment, the low-temperature refrigerant flow path further includes a first solenoid valve, a second solenoid valve, a third solenoid valve, a fourth solenoid valve, a cold accumulator, and an air pump. The first end of the first solenoid valve is connected to the second input end of the evaporator-condenser; the second end of the first solenoid valve is connected to the first end of the second solenoid valve; the second end of the second solenoid valve is connected to the second end of the evaporator; the first end of the third solenoid valve is connected to the second end of the evaporator; the second end of the third solenoid valve is connected to the first end of the fourth solenoid valve; the second end of the fourth solenoid valve is connected to the first end of the evaporator; the first end of the cold accumulator is connected to the first end of the fourth solenoid valve; the second end of the cold accumulator is connected to the first end of the air pump; and the second end of the air pump is connected to the second end of the first solenoid valve.

[0051] As an alternative example, the high-temperature refrigerant flow path is also used when the refrigeration equipment is started, the high-temperature compressor starts at a first frequency and rises to a second frequency at a first rate to pre-cool the low-temperature refrigerant flow path, wherein the second frequency is greater than the first frequency.

[0052] As an alternative example, the low-temperature refrigerant flow path is also used to open the air pump, the first solenoid valve, and the third solenoid valve when the frequency of the high-temperature compressor reaches the second frequency, so that the high-temperature refrigerant flow path precools the low-temperature refrigerant flow path.

[0053] Optionally, in this embodiment, when the refrigeration equipment starts cooling, the high-temperature stage compressor starts at a low frequency (first frequency) and then increases to a high frequency (second frequency) at a first rate. The air pump, the first solenoid valve, and the third solenoid valve are energized, allowing the refrigerant to flow from the evaporator outlet through the first and third solenoid valves, the cold accumulator, and the air pump back to the evaporator-condenser, thereby achieving pre-cooling of the low-temperature stage refrigerant via the evaporator-condenser. The single-operation of the high-temperature stage compressor reduces the discharge pressure of the low-temperature stage compressor, ensuring reliable operation of the refrigeration system.

[0054] As an alternative example, the cryogenic refrigerant flow path is also used to close the air pump, the first solenoid valve, and the third solenoid valve when the discharge pressure of the cryogenic compressor is within a preset pressure range. The cryogenic compressor starts at a third frequency and rises to a fourth frequency at a second rate to cool the refrigeration equipment, wherein the fourth frequency is greater than the third frequency.

[0055] Optionally, in this embodiment, when the discharge pressure of the cryogenic compressor is within a preset pressure range, the air pump, the first solenoid valve and the third solenoid valve are de-energized and closed, the cryogenic compressor starts at a low frequency at a third frequency and increases at a second rate until it reaches the highest frequency, the fourth frequency, thereby deeply cooling the refrigeration equipment.

[0056] As an alternative example, the low-temperature refrigerant flow path is also used to open the air pump, the second solenoid valve, and the fourth solenoid valve to cool the cold storage unit when the evaporator temperature is lower than the first preset temperature.

[0057] Optionally, in this embodiment, when the evaporator temperature is lower than the first preset temperature, the air pump, the second solenoid valve and the fourth solenoid valve are energized and opened, and the low-temperature stage refrigeration cycle releases cold energy to the cold storage unit. The high-temperature stage compressor is turned on to realize that when the temperature of the cold storage unit is lower than the temperature of the low-temperature stage refrigerant, the cold storage unit absorbs heat from the low-temperature stage refrigerant, so that the low-temperature stage refrigerant is pre-cooled quickly and the low-temperature stage refrigeration system is started up faster.

[0058] As an alternative example, the low-temperature refrigerant flow path is also used to close the air pump, the second solenoid valve, and the fourth solenoid valve when the evaporation temperature is higher than the second preset temperature, so as to transfer the cold energy in the cold storage to the evaporator and reduce the evaporation temperature, wherein the second preset temperature is higher than the first preset temperature.

[0059] Optionally, in this embodiment, when the evaporator temperature is higher than the second preset temperature, the air pump, the second solenoid valve and the fourth solenoid valve are de-energized and shut down, and the low-temperature refrigeration cycle releases cold energy to the evaporator. This operating logic continues until the evaporator temperature and the temperature of the cold storage are both lower than the first preset temperature.

[0060] As an alternative example, the cryogenic refrigerant flow path is also used to open the air pump, the second solenoid valve, and the fourth solenoid valve in the event of a cryogenic compressor failure and shutdown, so as to transfer the cold energy in the accumulator to the evaporator.

[0061] Optionally, in this embodiment, when the low-temperature stage compressor fails and stops, the air pump, the second solenoid valve and the fourth solenoid valve are energized and opened to release the cold energy in the cold storage to the low-temperature stage refrigerant, which is then transferred to the evaporator, slowing down the heating rate of the evaporator and thus reducing the loss of refrigeration equipment.

[0062] Optionally, to illustrate with reference to an example, this application relates to a cascade refrigeration device, such as... Figure 2 The circuit diagram shown is of a cascade refrigeration system. The cascade refrigeration system consists of a high-temperature refrigerant flow path and a low-temperature refrigerant flow path. The high-temperature refrigerant flow path includes, in sequence, a high-temperature compressor A1, an anti-condensation pipe AC, a high-temperature condenser C, a high-temperature filter D1, a high-temperature capillary tube J1, and a gas-liquid separator GL. The low-temperature refrigerant flow path includes, in sequence, a low-temperature compressor A2, an oil separator O, a low-temperature filter D2, a low-temperature capillary tube J2, and an evaporator E. Between the outlet of evaporator E and the inlet of evaporator-condenser EC, there is a gas pump F, a cold accumulator B, a first solenoid valve CV1, a second solenoid valve CV2, a third solenoid valve CV3, and a fourth solenoid valve CV4. An oil return line 1 connects the low-temperature compressor and the oil separator. Heat exchange between the high-temperature and low-temperature refrigerant flow paths occurs through the evaporator-condenser EC. The gas-liquid separator GL stores the liquid refrigerant at the outlet of evaporator-condenser EC to prevent wet compression, which can cause liquid slugging in the compressor and shorten its lifespan. The anti-condensation pipe AC is encapsulated at the door seal, serving to heat the door seal and reduce condensation and frost formation. The first solenoid valve CV1, the third solenoid valve CV3, the cold accumulator B, and the air pump F are arranged between the evaporator E outlet and the evaporator-condenser EC inlet. When the discharge pressure is too high before the low-temperature stage compressor starts, it pre-cools the low-temperature stage refrigerant. The first solenoid valve CV1, the third solenoid valve CV3, and the air pump F control the opening and closing of this flow path. Furthermore, the second solenoid valve CV2, the fourth solenoid valve CV4, and the air pump F are arranged between the evaporator E inlet and outlet. When the low-temperature stage compressor fails and stops, it forces the low-temperature stage refrigerant from the evaporator E outlet through the solenoid valve, obtains cooling in the cold accumulator B, and then re-enters the evaporator E, delaying the temperature rise of the evaporator E. The second solenoid valve CV2, the fourth solenoid valve CV4, and the air pump F control the opening and closing of this flow path.

[0063] In this embodiment, the cascade refrigeration equipment can open the solenoid valve and air pump during the high-temperature stage of single-operation to draw the refrigerant from the low-pressure side to the high-pressure side for condensation, ensuring reliable start-up. When the temperature of the accumulator is lower than that of the low-temperature stage refrigerant, the accumulator absorbs heat from the low-temperature stage refrigerant, enabling rapid pre-cooling of the low-temperature stage refrigerant. Furthermore, after a compressor failure, the solenoid valve and air pump can open to release the cold energy of the accumulator to the low-temperature stage refrigerant, delaying the temperature rise of the evaporator and reducing product loss.

[0064] The specific implementation process is as follows: Figure 3 As shown:

[0065] Step 1: Power on the refrigeration equipment and start refrigeration;

[0066] Step 2: The high-temperature stage compressor A1 starts at a low frequency, such as 33Hz, and then rises to a high frequency, such as 75Hz, at the first rate. The air pump F, the first solenoid valve CV1, and the third solenoid valve CV3 are energized and opened, and the refrigerant on both the high and low pressure sides of the low-temperature stage is pre-cooled through the evaporator condenser EC.

[0067] Step 3: When the discharge pressure of the cryogenic compressor A2 is within the preset pressure range (e.g., 0.2-3MPa), the air pump F is de-energized and closed with the first solenoid valve CV1 and the third solenoid valve CV3.

[0068] Step 4: The low-temperature stage compressor A2 starts at a low frequency, such as 33Hz, and increases at a second rate until it reaches the highest frequency, such as 75Hz, to deeply cool the refrigeration equipment.

[0069] Step 5: When the evaporator E's evaporation temperature is lower than the first preset temperature (e.g., -86℃), the air pump F, the second solenoid valve CV2, and the fourth solenoid valve CV4 are energized and opened, and the low-temperature stage refrigeration cycle releases cold energy to the cold storage B.

[0070] Step Six: When the evaporator temperature of E is higher than the second preset temperature (e.g., -81℃), the air pump F, the second solenoid valve CV2, and the fourth solenoid valve CV4 are de-energized and closed, and the low-temperature refrigeration cycle releases cooling capacity to the evaporator E. This operating logic continues until both the temperature of the evaporator E and the temperature of the cold storage unit B are lower than the first preset temperature.

[0071] Step 7: When the low-temperature stage compressor A2 fails and stops, the air pump F is energized and opened with the second solenoid valve CV2 and the fourth solenoid valve CV4, releasing the cold energy in the cold storage B to the low-temperature stage refrigerant, which is then transferred to the evaporator E, slowing down the heating rate of the evaporator E and thus reducing the loss of stored products.

[0072] It should be noted that, for the sake of simplicity, the aforementioned embodiments of the refrigeration equipment are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

Claims

1. A cascade refrigeration device, characterized in that, include: A high-temperature refrigerant flow path is provided, wherein the input end of the high-temperature refrigerant flow path is connected to the first output end of the evaporator-condenser, and the output end of the high-temperature refrigerant flow path is connected to the first input end of the evaporator-condenser. The high-temperature refrigerant flow path is used to pre-cool the low-temperature refrigerant flow path. The low-temperature refrigerant flow path has its input end connected to the second output end of the evaporator-condenser, and its output end connected to the second input end of the evaporator-condenser. The low-temperature refrigerant flow path is used to refrigerate the refrigeration equipment. The evaporator-condenser is used to exchange the heat generated by the high-temperature refrigerant flow path and the low-temperature refrigerant flow path; The low-temperature refrigerant flow path includes: a low-temperature filter, the first end of which is connected to the second output end of the evaporator-condenser, and the second end of which is connected to the first end of the low-temperature capillary; the low-temperature capillary, the second end of which is connected to the first end of the evaporator; the evaporator, the second end of which is connected to the first end of the low-temperature compressor; the low-temperature compressor, the second end of which is connected to the first end of the oil separator; and the oil separator, the second end of which is connected to the second input end of the evaporator-condenser. The low-temperature refrigerant flow path further includes: a first solenoid valve, the first end of which is connected to the second input end of the evaporator-condenser, and the second end of which is connected to the first end of a second solenoid valve; a second solenoid valve, the second end of which is connected to the second end of the evaporator; a third solenoid valve, the first end of which is connected to the second end of the evaporator, and the second end of which is connected to the first end of a fourth solenoid valve; a fourth solenoid valve, the second end of which is connected to the first end of the evaporator; a cold accumulator, the first end of which is connected to the first end of the fourth solenoid valve, and the second end of which is connected to the first end of an air pump; and an air pump, the second end of which is connected to the second end of the first solenoid valve.

2. The refrigeration equipment according to claim 1, characterized in that, The high-temperature refrigerant flow path includes: A gas-liquid separator, wherein the first end of the gas-liquid separator is connected to the first output end of the evaporator-condenser, and the second end of the gas-liquid separator is connected to the first end of the high-temperature stage compressor, and the gas-liquid separator is used to store the liquid refrigerant discharged from the evaporator-condenser; The high-temperature stage compressor, wherein the second end of the high-temperature stage compressor is connected to the first end of the anti-condensation pipe; The anti-condensation tube has its second end connected to the first end of the high-temperature condenser, and the anti-condensation tube is used to heat the door seal of the refrigeration equipment. The high-temperature stage condenser, wherein the second end of the high-temperature stage condenser is connected to the first end of the high-temperature stage filter; The high-temperature filter, wherein the second end of the high-temperature filter is connected to the first end of the high-temperature capillary; The high-temperature capillary tube has its second end connected to the first input end of the evaporator-condenser.

3. The refrigeration equipment according to claim 2, characterized in that, The high-temperature refrigerant flow path is also used to pre-cool the low-temperature refrigerant flow path when the refrigeration equipment is started, wherein the high-temperature compressor starts at a first frequency and rises to a second frequency at a first rate. The second frequency is greater than the first frequency.

4. The refrigeration equipment according to claim 3, characterized in that, The low-temperature refrigerant flow path is also used to open the air pump, the first solenoid valve, and the third solenoid valve when the frequency of the high-temperature compressor reaches the second frequency, so that the high-temperature refrigerant flow path pre-cools the low-temperature refrigerant flow path.

5. The refrigeration equipment according to claim 4, characterized in that, The low-temperature stage refrigerant flow path is also used to close the air pump, the first solenoid valve, and the third solenoid valve when the discharge pressure of the low-temperature stage compressor is within a preset pressure range. The low-temperature stage compressor starts at a third frequency and increases to a fourth frequency at a second rate to cool the refrigeration equipment, wherein the fourth frequency is greater than the third frequency.

6. The refrigeration equipment according to claim 5, characterized in that, The low-temperature refrigerant flow path is also used to open the air pump, the second solenoid valve, and the fourth solenoid valve to cool the cold storage unit when the evaporator temperature is lower than the first preset temperature.

7. The refrigeration equipment according to claim 6, characterized in that, The low-temperature refrigerant flow path is also used to close the air pump, the second solenoid valve, and the fourth solenoid valve when the evaporation temperature is higher than the second preset temperature, so as to transfer the cold energy in the cold storage to the evaporator and reduce the evaporation temperature, wherein the second preset temperature is greater than the first preset temperature.

8. The refrigeration equipment according to claim 1, characterized in that, The low-temperature stage refrigerant flow path is also used to open the air pump, the second solenoid valve, and the fourth solenoid valve in the event of a failure and shutdown of the low-temperature stage compressor, so as to transfer the cold energy in the cold accumulator to the evaporator.

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