Double-refrigerant circulating refrigerating system for centrifugal machine and control method

Abstract

The invention relates to the technical field of refrigerating systems, and discloses a double-refrigerant circulation refrigerating system for a centrifugal machine and a control method.The refrigerating system comprises a first refrigerant circulation system mainly composed of a first refrigerant storage tank, a refrigerating unit, a first circulating pump, a heat exchanger, a refrigerant pipeline and a controller; the second refrigerant circulation system mainly comprises a second refrigerant storage tank, a second circulating pump, a heat exchanger, a refrigerant pipeline and a controller; the first refrigerant circulation and the second refrigerant circulation are mutually coupled through the heat exchanger; the first refrigerant circulation comprises a first refrigerant refrigeration branch and a centrifugal machine first temperature zone refrigeration branch, and the second refrigerant circulation comprises a second refrigerant refrigeration branch and a centrifugal machine second temperature zone refrigeration branch. According to the method, the flow and temperature of refrigerants of different branches are adjusted, the fine refrigeration requirements of dynamic changes of different components of the centrifugal machine in the corresponding operation stages are met, the stability of the production process is improved, and more energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration systems, and particularly relates to a dual-refrigerant circulation refrigeration system and a control method for a centrifuge. Background Art

[0002] Some centrifuges used in industrial production have relatively complex structures, and there are significantly different refrigeration requirements for two different components of the same centrifuge. In traditional factories, the common practice is to equip two sets of refrigeration units, and perform separate refrigeration through their respective independent refrigerant circulation pipelines. This mode is simple and extensive, and it is difficult for the two independent refrigeration cycles to effectively cooperate to provide the best overall refrigeration effect for the centrifuge. It is usually applicable to the production of low-value-added products with low requirements for refrigeration process control, such as the food industry.

[0003] In modern smart factories, especially for high-value-added products represented by blood products, the strictness of their production processes puts higher requirements on the refined refrigeration of centrifuges, and the traditional refrigeration mode is no longer applicable. To solve the above problems, effectively integrating two separate refrigerant circulation refrigeration systems into a refined controllable dual-refrigerant circulation refrigeration system has become a new alternative direction. Summary of the Invention

[0004] To solve the deficiencies in the above-mentioned prior art, the present invention provides a dual-refrigerant circulation refrigeration system and a control method for a centrifuge, which can meet the refined refrigeration requirements that dynamically change for different components of the centrifuge during corresponding operation stages, improve the stability of the production process, and be more energy-saving and environmentally friendly.

[0005] To achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A dual-refrigerant circulation refrigeration system for a centrifuge includes a first refrigerant circulation mainly composed of a first refrigerant storage tank, a refrigeration unit, a first circulation pump, a heat exchanger, a refrigerant pipeline and a controller, and also includes a second refrigerant circulation mainly composed of a second refrigerant storage tank, a second circulation pump, a heat exchanger, a refrigerant pipeline and a controller; the first refrigerant circulation and the second refrigerant circulation are coupled to each other through the heat exchanger;

[0007] The first refrigerant circulation includes 2 circulation branches. The first branch of the first refrigerant circulation leads from the liquid outlet of the first refrigerant storage tank, passes through the refrigeration unit, the first circulation pump, the first refrigerant inlet of the heat exchanger, the first refrigerant outlet of the heat exchanger, and returns to the first refrigerant storage tank; the second branch of the first refrigerant circulation leads from the liquid outlet of the first refrigerant storage tank, passes through the refrigeration unit, the first circulation pump, the first refrigerant inlet of the centrifuge, cools the first temperature zone of the centrifuge, and then returns to the first refrigerant storage tank from the first refrigerant outlet of the centrifuge;

[0008] The second refrigerant cycle includes two circulation branches. The first branch of the second refrigerant cycle leads from the liquid outlet of the second refrigerant storage tank, through the second circulation pump, the second refrigerant inlet of the heat exchanger, the second refrigerant outlet of the heat exchanger, and back to the second refrigerant storage tank. The second branch of the second refrigerant cycle leads from the liquid outlet of the second refrigerant storage tank, through the second circulation pump, the second refrigerant inlet of the heat exchanger, the second refrigerant outlet of the heat exchanger, the second refrigerant inlet of the centrifuge to cool the second temperature zone of the refrigeration centrifuge, and then back to the second refrigerant storage tank from the second refrigerant outlet of the centrifuge.

[0009] Further, a first automatic switch valve is installed at the liquid outlet of the first refrigerant storage tank in the first refrigerant cycle. A fourth automatic switch valve is installed on the pipeline in front of the first refrigerant inlet of the heat exchanger in the first branch of the first refrigerant cycle. A fifth automatic switch valve and a first automatic regulating valve are installed on the pipeline behind the first refrigerant outlet of the heat exchanger. In the second branch of the first refrigerant cycle, a second automatic switch valve, a third temperature sensor, and a first mass flowmeter are installed on the pipeline in front of the first refrigerant inlet of the centrifuge. A third automatic switch valve, a fifth temperature sensor, and a first pressure sensor are installed on the pipeline behind the first refrigerant outlet of the centrifuge.

[0010] Further, a sixth automatic switch valve is installed at the liquid outlet of the second refrigerant storage tank in the second refrigerant cycle. An eighth automatic switch valve and a second automatic regulating valve are installed near the liquid return port of the second refrigerant storage tank in the first branch of the second refrigerant cycle. A ninth automatic switch valve, a fourth temperature sensor, and a second mass flowmeter are installed on the pipeline in front of the second refrigerant inlet of the centrifuge in the second branch of the second refrigerant cycle. A tenth automatic switch valve, a sixth temperature sensor, and a second pressure sensor are installed on the pipeline behind the second refrigerant outlet of the centrifuge.

[0011] Further, a first temperature sensor and a first liquid level sensor are installed at the bottom of the first refrigerant storage tank. An emptying valve is installed on the pipeline at the bottom outlet of the first refrigerant storage tank, and the emptying valve is a thirteenth automatic switch valve. A second temperature sensor and a second liquid level sensor are installed at the bottom of the second refrigerant storage tank. An emptying valve is installed on the pipeline at the bottom outlet of the second refrigerant storage tank, and the emptying valve is a seventh automatic switch valve. A flame arrester breather valve is installed on the top of the second refrigerant storage tank.

[0012] Emptying valves are installed on the first circulation pump, the second circulation pump, and the heat exchanger respectively.

[0013] Further, the controller includes a central processing unit, a filtering / amplifying circuit, an A / D conversion circuit, a D / A conversion circuit, a display screen and buttons; the first to sixth temperature sensors, the first / second mass flow meters, the first / second pressure sensors, and the first / second liquid level sensors are all connected to the filtering / amplifying circuit, the filtering / amplifying circuit is connected to the A / D conversion circuit, and the A / D conversion circuit is connected to the central processing unit; the first / second automatic regulating valves are connected to the D / A conversion circuit, and the D / A conversion circuit is connected to the central processing unit; the first / second circulation pumps, all the automatic switching valves, and the refrigeration unit are connected to the central processing unit.

[0014] A control method for a centrifuge dual-refrigerant cycle refrigeration system including the above, comprising:

[0015] A. When the system operation instruction is to start the first refrigerant storage tank refrigeration cycle, enter step S11;

[0016] B. When the system operation instruction is to start the second refrigerant storage tank refrigeration cycle, enter step S12;

[0017] C. When the system operation instruction is to start the first refrigerant storage tank to refrigerate the first temperature zone of the centrifuge, enter step S21;

[0018] D. When the system operation instruction is to start the second refrigerant storage tank to refrigerate the second temperature zone of the centrifuge, enter step S22;

[0019] E. When the system operation instruction is to stop the second refrigerant storage tank from refrigerating the second temperature zone of the centrifuge, enter step S31;

[0020] F. When the system operation instruction is to stop the first refrigerant storage tank from refrigerating the first temperature zone of the centrifuge, enter step S32;

[0021] G. When the system operation instruction is to stop the second refrigerant storage tank refrigeration cycle, enter step S41;

[0022] H. When the system operation instruction is to stop the first refrigerant storage tank refrigeration cycle, enter step S42.

[0023] Further, the step S11 specifically includes: opening the first automatic switching valve, the fourth automatic switching valve, and the fifth automatic switching valve, the first automatic regulating valve operates according to a preset first opening value, and the refrigeration unit is started; the first refrigeration medium in the first refrigerant storage tank returns to the first refrigerant storage tank after passing through the refrigeration unit, the first circulation pump, and the heat exchanger;

[0024] The specific steps of S12 include: automatically detecting and judging whether the first temperature sensor in the first refrigerant storage tank reaches the preset temperature range. After reaching, open the sixth automatic switch valve and the eighth automatic switch valve, the second automatic regulating valve operates according to the preset first opening value, and start the second circulation pump; the second refrigerant medium in the second refrigerant storage tank returns to the second refrigerant storage tank after being refrigerated by the second circulation pump and the heat exchanger.

[0025] Further, the specific steps of S21 include automatically detecting and judging that step S11 operates normally and the first temperature sensor reaches the preset temperature range, opening the second automatic switch valve and the third automatic switch valve, starting the first circulation pump to operate at the first set pump speed ω set1(51) , the first automatic regulating valve operates according to the preset second opening value, detecting the real-time flow rate of the first mass flowmeter, and if it reaches the preset flow rate range within the time period t1, it is determined that S21 operates normally;

[0026] If the real-time pressure P of the first pressure sensor act(91) reaches the first set pressure value P within the set time period t2 set1(91) , trigger an alarm prompt; if the real-time pressure P of the first pressure sensor act(91) reaches the second set pressure value P within the set time period t3 set2(91) , immediately stop the operation of the first circulation pump; P set2(91) >P set1(91) ;

[0027] The specific steps of S22 include automatically detecting and judging that step S12 operates normally and the second temperature sensor reaches the preset temperature range, opening the ninth automatic switch valve and the tenth automatic switch valve, the second automatic regulating valve operates according to the preset second opening value, detecting the real-time flow rate of the second mass flowmeter, and if it reaches the preset flow rate range within the time period t4, it is determined that S22 operates normally; when S22 operates normally, on the premise of ensuring that the flow rate of the second mass flowmeter is within the preset flow rate range:

[0028] When the real-time temperature T of the fourth temperature sensor act(84) is higher than the first set value T set1(84) , gradually adjust the opening value of the second automatic regulating valve according to the output result of PID control, and the gradual adjustment speed is less than V1; when the real-time temperature T act(84) decreases to the first set value T set1(84) -T1, gradually adjust the opening value of the second automatic regulating valve according to the output result of PID control, and the gradual adjustment speed is less than V2, V1>V2, and T1 is a positive number;

[0029] When the real-time temperature T of the fourth temperature sensor act(84) is higher than the second set value T set2(84)When it is, the opening value of the first automatic regulating valve is gradually adjusted according to the output result of the PID control, and the gradual adjustment speed is less than V3; T set2(84) >T set1(84) ;

[0030] When the real-time temperature T of the fourth temperature sensor act(84) is lower than the third set value T set3(84) When it is, the opening value of the second automatic regulating valve is gradually adjusted according to the output result of the PID control, and the gradual adjustment speed is less than V4; when the real-time temperature T act(84) rises to the third set value T set3(84) + T2, the opening value of the second automatic regulating valve is gradually adjusted according to the output result of the PID control, and the gradual adjustment speed is less than V5; V4 > V5, T set2(84) >T set1(84) >T set3(84) , T2 is a positive number;

[0031] When the real-time temperature T of the second temperature sensor act(82) is higher than the first set value T set1(82) When it is, the opening value of the first automatic regulating valve is gradually adjusted according to the output result of the PID control, and the increase in the opening value will not cause the flow rate of the first mass flowmeter to be lower than the lower limit warning value of the set range. The gradual adjustment speed is less than V6, and at the same time, the pump speed of the first circulation pump is increased to the second set value ω set2(51) ; when the real-time temperature T act(82) drops to the first set value T set1(82) - T3, the opening value of the first automatic regulating valve is gradually adjusted according to the output result of the PID control, and the gradual adjustment speed is less than V7. The pump speed of the first circulation pump is restored to the first set value ω set1(51) ; V6 > V7, ω set2(51) >ω set1(51) , T3 is a positive number;

[0032] When the real-time pressure P of the second pressure sensor act(92 ) reaches the first set pressure value P within the set time period t1 set1(92) When it is, an alarm prompt is triggered; when the real-time pressure P of the second pressure sensor act(92) reaches the second set pressure value P within the set time period t2 set2(92) When it is, the operation of the second circulation pump is immediately stopped; P set2(92) >P set1(92) .

[0033] Furthermore, the S31 step specifically includes that the second automatic regulating valve operates according to the preset third opening value, and the ninth automatic switching valve and the tenth automatic switching valve are closed;

[0034] The specific steps of S32 include that the first automatic regulating valve operates according to a preset third opening value, the first circulation pump is stopped, and the second automatic switch valve and the third automatic switch valve are closed.

[0035] The specific steps of S41 include that the second circulation pump is stopped, and the sixth automatic switch valve, the eighth automatic switch valve and the second automatic regulating valve are closed.

[0036] The specific steps of S42 include that the refrigeration unit is stopped, and the first automatic switch valve, the fourth automatic switch valve, the fifth automatic switch valve and the first automatic regulating valve are closed.

[0037] Furthermore, the output result of the PID control is the operation result based on the difference between the current real-time temperature and the set temperature, which is expressed as follows:

[0038]

[0039] Among them, Q(t) represents the output result of the PID control, K p 、K i 、K d respectively represent the proportional coefficient, integral coefficient and differential coefficient of the PID control, C represents the compensation term, T set represents the set temperature, T act represents the real-time temperature, and E(t) represents the real-time temperature difference; for different set temperatures T set , parameter groups K p 、K i 、K d and C that are matched with each refrigeration stage are pre-configured.

[0040] The beneficial effects of the present invention are as follows:

[0041] The dual-refrigerant cycle refrigeration system for a centrifuge of the present invention can achieve dynamic and refined refrigeration control: on the premise of fully ensuring the refrigeration effect, the present invention can realize the dynamic and refined control of the refrigerant temperature and flow rate through the mass flow meters, automatic regulating valves, mutually coupled heat exchangers and refrigeration control methods of the two refrigerant circulation pipelines, so as to meet the dynamic and refined refrigeration requirements of different components (different temperature zones) of the centrifuge in the corresponding operation stages.

[0042] The dual-refrigerant cycle refrigeration system for a centrifuge of the present invention can improve the stability of the production process: thanks to the optimization of the integrated system structure and the refined control of the refrigeration effect by the fusion method, the stability of the production process is improved.

[0043] The dual-refrigerant cycle refrigeration system for a centrifuge of the present invention reduces equipment usage, saves energy and is environmentally friendly. Compared with the two refrigeration units used in the traditional mode, the integrated dual-refrigerant cycle refrigeration system meets the dual refrigeration requirements through one refrigerant refrigeration unit, and the flow rates of the two refrigerants are dynamically and coordinately distributed. The refrigeration method of the integrated system is more in line with the development trend of the industry in terms of energy conservation and environmental protection.

[0044] The dual-refrigerant cycle refrigeration system for a centrifuge of the present invention has a high degree of automation. This integrated system is automatically controlled by a computer program, and users can write control requirements into the program according to process requirements and actual situations, including but not limited to automatic control of refrigeration, automatic emergency handling of abnormal situations and safety protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1 It is a schematic structural diagram of the system of the present invention.

[0047] Figure 2 It is a principle block diagram of the controller.

[0048] Figure 3 It is a principle block diagram of the temperature control of the fourth temperature sensor in step S22.

[0049] Figure 4 It is a principle block diagram of the temperature control of the second temperature sensor in step S22.

[0050] Reference numerals: 1 - centrifuge, 11 - first refrigerant inlet of the centrifuge, 12 - first refrigerant outlet of the centrifuge, 13 - second refrigerant inlet of the centrifuge, 14 - second refrigerant outlet of the centrifuge, 21 - first refrigerant storage tank, 22 - second refrigerant storage tank, 3 - refrigeration unit, 4 - heat exchanger, 41 - first refrigerant inlet of the heat exchanger, 42 - first refrigerant outlet of the heat exchanger, 43 - second refrigerant inlet of the heat exchanger, 44 - second refrigerant outlet of the heat exchanger, 51 - first circulation pump, 52 - second circulation pump, 601 - 613 - first to thirteenth automatic switching valves, 71 - first automatic regulating valve, 72 - second automatic regulating valve, 81 - 86 - first to sixth temperature sensors, 91 - first pressure sensor, 92 - second pressure sensor, 101 - first mass flowmeter, 102 - second mass flowmeter, 111 - flame arrestor breather valve, 121 - first level gauge, 122 - second level gauge, 131 - hand valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. The components of the embodiments of this application usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0052] A dual-refrigerant cycle refrigeration system for a centrifuge includes a first refrigerant cycle mainly composed of a first refrigerant storage tank 21, a refrigeration unit 3, a first circulation pump 51, a heat exchanger 4, refrigerant pipelines, and a controller, and also includes a second refrigerant cycle mainly composed of a second refrigerant storage tank 22, a second circulation pump 52, a heat exchanger 4, refrigerant pipelines, and a controller; the first refrigerant cycle and the second refrigerant cycle are coupled to each other through the heat exchanger 4.

[0053] The first refrigerant cycle includes two circulation branches. The first branch of the first refrigerant cycle leads from the liquid outlet of the first refrigerant storage tank 21, passes through the refrigeration unit 3, the first circulation pump 51, the first refrigerant inlet 41 of the heat exchanger, the first refrigerant outlet 42 of the heat exchanger, and returns to the first refrigerant storage tank 21. The second branch of the first refrigerant cycle leads from the liquid outlet of the first refrigerant storage tank 21, passes through the refrigeration unit 3, the first circulation pump 51, the first refrigerant inlet 11 of the centrifuge, cools the centrifuge 1, and then returns to the first refrigerant storage tank 21 from the first refrigerant outlet 12 of the centrifuge. The second refrigerant cycle includes two circulation branches. The first branch of the second refrigerant cycle leads from the liquid outlet of the second refrigerant storage tank 22, passes through the second circulation pump 52, the second refrigerant inlet 43 of the heat exchanger, the second refrigerant outlet 44 of the heat exchanger, and returns to the second refrigerant storage tank 22. The second branch of the second refrigerant cycle leads from the liquid outlet of the second refrigerant storage tank 22, passes through the second circulation pump 52, the second refrigerant inlet 43 of the heat exchanger, the second refrigerant outlet 44 of the heat exchanger, the second refrigerant inlet 13 of the centrifuge, cools the centrifuge 1, and then returns to the second refrigerant storage tank 22 from the second refrigerant outlet 14 of the centrifuge.

[0054] Further, a first automatic switch valve 601 is installed at the liquid outlet of the first refrigerant storage tank 21 in the first refrigerant cycle. A fourth automatic switch valve 604 is installed on the pipeline in front of the first refrigerant inlet 41 of the heat exchanger in the first branch of the first refrigerant cycle. A fifth automatic switch valve 605 and a first automatic regulating valve 71 are installed on the pipeline behind the first refrigerant outlet 42 of the heat exchanger. A second automatic switch valve 602, a third temperature sensor 83, and a first mass flowmeter 101 are installed on the pipeline in front of the first refrigerant inlet 11 of the centrifuge in the second branch of the first refrigerant cycle. A third automatic switch valve 603, a fifth temperature sensor 85, and a first pressure sensor 91 are installed on the pipeline behind the first refrigerant outlet 12 of the centrifuge.

[0055] Further, a sixth automatic switch valve 606 is installed at the liquid outlet of the second refrigerant storage tank 22 in the second refrigerant cycle. An eighth automatic switch valve 608 and a second automatic regulating valve 72 are installed near the liquid return port of the second refrigerant storage tank 22 in the first branch of the second refrigerant cycle. A ninth automatic switch valve 609, a fourth temperature sensor 84, and a second mass flowmeter 102 are installed on the pipeline in front of the second refrigerant inlet 13 of the centrifuge in the second branch of the second refrigerant cycle. A tenth automatic switch valve 610, a sixth temperature sensor 86, and a second pressure sensor 92 are installed on the pipeline behind the second refrigerant outlet 14 of the centrifuge.

[0056] Further, a first temperature sensor 81 and a first liquid level sensor 121 are installed at the bottom of the first refrigerant storage tank 21. A drain valve is installed on the outlet pipeline at the bottom of the first refrigerant storage tank 21, and the drain valve is a thirteenth automatic switch valve 613.

[0057] Further, a second temperature sensor 82 and a second liquid level sensor 122 are installed at the bottom of the second refrigerant storage tank 22. A drain valve is installed on the outlet pipeline at the bottom of the second refrigerant storage tank 22, and the drain valve is a seventh automatic switch valve 607. A flame arrester breather valve 111 is installed on the top of the second refrigerant storage tank 22.

[0058] Further, a drain valve is installed on the first circulation pump 51, and the drain valve is an eleventh automatic switch valve 611; a drain valve is installed on the second circulation pump 52, and the drain valve is a twelfth automatic switch valve 612; a drain valve is installed on the heat exchanger 4, and the drain valve is a manual valve 131.

[0059] Further, the controller includes a central processing unit, a filtering / amplifying circuit, an A / D conversion circuit, a D / A conversion circuit, a display screen and buttons; the first to sixth temperature sensors, the first / second mass flow meters, the first / second pressure sensors, and the first / second liquid level sensors are all connected to the filtering / amplifying circuit, the filtering / amplifying circuit is connected to the A / D conversion circuit, the A / D conversion circuit is connected to the central processing unit, the first / second automatic regulating valves are connected to the D / A conversion circuit, and the D / A conversion circuit is connected to the central processing unit; the first / second circulation pumps, all the automatic switching valves, and the refrigeration unit are connected to the central processing unit.

[0060] In practical applications of the present invention, hierarchical permission management accounts can be set for different users, and operators with corresponding permissions can perform parameter settings, start and stop controls, data queries, process message and exception alarm handling, etc. through the operation interface.

[0061] The present invention also provides a control method for a centrifuge dual-refrigerant circulation refrigeration system, including:

[0062] A. When the system operation instruction is to start the refrigeration cycle of the first refrigerant storage tank 21, enter step S11;

[0063] B. When the system operation instruction is to start the refrigeration cycle of the second refrigerant storage tank 22, enter step S12;

[0064] C. When the system operation instruction is to start the first refrigerant storage tank 21 to refrigerate the centrifuge 1, enter step S21;

[0065] D. When the system operation instruction is to start the second refrigerant storage tank 22 to refrigerate the centrifuge 1, enter step S22;

[0066] E. When the system operation instruction is to stop the second refrigerant storage tank 22 from refrigerating the centrifuge 1, enter step S31;

[0067] F. When the system operation instruction is to stop the first refrigerant storage tank 21 from refrigerating the centrifuge 1, enter step S32;

[0068] G. When the system operation instruction is to stop the refrigeration cycle of the second refrigerant storage tank 22, enter step S41;

[0069] H. When the system operation instruction is to stop the refrigeration cycle of the first refrigerant storage tank 21, enter step S42.

[0070] Specifically, the step S11 includes: opening the first automatic switching valve 601, the fourth automatic switching valve 604, and the fifth automatic switching valve 605, and the first automatic regulating valve 71 according to a preset first opening value F 711Run and start the refrigeration unit 3; the first refrigeration medium in the first refrigerant storage tank 21 returns to the first refrigerant storage tank 21 after passing through the refrigeration unit 3, the first circulation pump 51, and the heat exchanger 4.

[0071] The step S12 includes: automatically detecting and judging whether the first temperature sensor 81 in the first refrigerant storage tank 21 reaches the preset temperature range. After reaching, open the sixth automatic switch valve 606 and the eighth automatic switch valve 608, and the second automatic regulating valve 72 is adjusted according to the preset first opening value F 721 Run and start the second circulation pump 52; the second refrigeration medium in the second refrigerant storage tank 22 returns to the second refrigerant storage tank 22 after being refrigerated by the second circulation pump 52 and the heat exchanger 4.

[0072] The step S21 specifically includes automatically detecting and judging that the step S11 is running normally and the first temperature sensor 81 reaches the preset temperature range, opening the second automatic switch valve 602 and the third automatic switch valve 603, and starting the first circulation pump 51 at the pump speed of the first set value ω set1(51) Run, and the first automatic regulating valve 71 is adjusted according to the preset second opening value F 712 Run, detect the real-time flow rate of the first mass flowmeter 101, and if it reaches the preset flow rate range within the time period t1, it is determined that S21 is running normally;

[0073] If the real-time pressure P of the first pressure sensor 91 act(91) reaches the first set pressure value P within the set time period t2 set1(91) a warning prompt is triggered; if the real-time pressure P of the first pressure sensor 91 act(91) reaches the second set pressure value P within the set time period t3 set2(91) the operation of the first circulation pump 51 is immediately stopped; P set2(91) >P set1(91) .

[0074] The step S22 specifically includes automatically detecting and judging that the step S12 is running normally and the second temperature sensor 82 reaches the preset temperature range, opening the ninth automatic switch valve 609 and the tenth automatic switch valve 610, and the second automatic regulating valve 72 is adjusted according to the preset second opening value F 722 Run, detect the real-time flow rate of the second mass flowmeter 102, and if it reaches the preset flow rate range within the time period t4, it is determined that S22 is running normally.

[0075] When S22 is running normally, on the premise of ensuring that the flow rate of the second mass flowmeter 102 is within the preset flow rate range,

[0076] when the real-time temperature T of the fourth temperature sensor 84 act(84) is higher than the first set value T set1(84)When, according to the output result of the PID control, gradually adjust the opening value of the second automatic regulating valve 72, and the gradual adjustment speed is less than V1; when the real-time temperature T act(84) decreases to the first set value T set1(84) - T1, according to the output result of the PID control, gradually adjust the opening value of the second automatic regulating valve 72, and the gradual adjustment speed is less than V2, V1 > V2, and T1 is a positive number;

[0077] When the real-time temperature T of the fourth temperature sensor 84 act(84) is higher than the second set value T set2(84) When, according to the output result of the PID control, gradually adjust the opening value of the first automatic regulating valve 71, and the gradual adjustment speed is less than V3; T set2(84) > T set1(84) ;

[0078] When the real-time temperature T of the fourth temperature sensor 84 act(84) is lower than the third set value T set3(84) When, according to the output result of the PID control, gradually adjust the opening value of the second automatic regulating valve 72, and the gradual adjustment speed is less than V4; when the real-time temperature T act(84) rises to the third set value T set3(84) + T2, according to the output result of the PID control, gradually adjust the opening value of the second automatic regulating valve 72, and the gradual adjustment speed is less than V5; V4 > V5, T set2(84) > T set1(84) > T set3(84) , and T2 is a positive number.

[0079] When the real-time temperature T of the second temperature sensor 82 act(82) is higher than the first set value T set1(82) When, according to the output result of the PID control, gradually adjust the opening value of the first automatic regulating valve 71, and the increase in the opening value will not cause the flow rate of the first mass flowmeter 101 to be lower than the lower warning value of the set range, and the gradual adjustment speed is less than V6. At the same time, increase the pump speed of the first circulation pump 51 to the second set value ω set2(51) ; when the real-time temperature T act(82) drops to the first set value T set1(82) - T3, according to the output result of the PID control, gradually adjust the opening value of the first automatic regulating valve 71, and the gradual adjustment speed is less than V7, and the pump speed of the first circulation pump 51 returns to the first set value ω set1(51) ; V6 > V7, ω set2(51) > ω set1(51) , and T3 is a positive number;

[0080] When the real-time pressure P of the second pressure sensor 92 act(92) reaches the first set pressure value P within the set time period t1 set1(92)When S22 is triggered, an alarm prompt is given; when the real-time pressure P of the second pressure sensor 92 act(92) reaches the second set pressure value P within the set time period t2 set2(92) , S22 immediately stops the operation of the second circulation pump 52; P set2(92) >P set1(92) .

[0081] The specific steps of S31 include that the second automatic regulating valve 72 operates according to the preset third opening value F 723 , and closes the ninth automatic switch valve 609 and the tenth automatic switch valve 610.

[0082] The specific steps of S32 include that the first automatic regulating valve 71 operates according to the preset third opening value F 713 , stops the first circulation pump 51, and closes the second automatic switch valve 602 and the third automatic switch valve 603.

[0083] The specific steps of S41 include stopping the second circulation pump 52, and closing the sixth automatic switch valve 606, the eighth automatic switch valve 608 and the second automatic regulating valve 72.

[0084] The specific steps of S42 include stopping the refrigeration unit 4, and closing the first automatic switch valve 601, the fourth automatic switch valve 604, the fifth automatic switch valve 605 and the first automatic regulating valve 71.

[0085] Preferably, the output result of the PID control is the operation result based on the difference between the current real-time temperature and the set temperature, and can be expressed as follows:

[0086]

[0087] Among them, Q(t) represents the output result of the PID control, K p , K i , K d respectively represent the proportional coefficient, integral coefficient, and differential coefficient of the PID control, C represents the compensation term, T set represents the set temperature, T act represents the real-time temperature, and E(t) represents the real-time temperature difference; for different set temperatures T set , parameter groups K p , K i , K d and C that are matched with each refrigeration stage are pre-configured.

[0088] Furthermore, the system controls and adjusts the real-time temperature difference as the control parameter for the next refrigeration cycle until the refrigeration process reaches a stable state.

[0089] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention. However, these corresponding changes and modifications should all fall within the protection scope of the appended claims of the present invention.

Claims

1. A dual refrigerant circulation refrigeration system for a centrifuge, characterized in that: It includes a first refrigerant cycle mainly composed of a first refrigerant storage tank, a refrigeration unit, a first circulation pump, a heat exchanger, a refrigerant pipeline and a controller, and also includes a second refrigerant cycle mainly composed of a second refrigerant storage tank, a second circulation pump, a heat exchanger, a refrigerant pipeline and a controller; the first refrigerant cycle and the second refrigerant cycle are coupled to each other through a heat exchanger; The first refrigerant cycle includes two circulation branches. The first branch of the first refrigerant cycle returns to the first refrigerant storage tank from the first refrigerant storage tank outlet through the refrigeration unit, the first circulation pump, the first refrigerant inlet of the heat exchanger, and the first refrigerant outlet of the heat exchanger; the second branch of the first refrigerant cycle returns to the first refrigerant storage tank from the first refrigerant storage tank outlet through the refrigeration unit, the first circulation pump, the first refrigerant inlet of the centrifuge, and the first temperature zone of the centrifuge after refrigeration through the first refrigerant outlet of the centrifuge; The second refrigerant cycle includes two circulation branches. The first branch of the second refrigerant cycle goes from the liquid outlet of the second refrigerant storage tank through the second circulation pump, the second refrigerant inlet of the heat exchanger, and the second refrigerant outlet of the heat exchanger to return to the second refrigerant storage tank; the second branch of the second refrigerant cycle goes from the liquid outlet of the second refrigerant storage tank through the second circulation pump, the second refrigerant inlet of the heat exchanger, the second refrigerant outlet of the heat exchanger, and the second refrigerant inlet of the centrifuge to refrigerate the second temperature zone of the centrifuge, and then returns to the second refrigerant storage tank from the second refrigerant outlet of the centrifuge.

2. The dual refrigerant circulation refrigeration system for a centrifuge according to claim 1, characterized in that: The first refrigerant cycle is provided with a first automatic switching valve at the liquid outlet of the first refrigerant storage tank, a fourth automatic switching valve is provided on the front end pipeline of the first refrigerant inlet of the heat exchanger in the first branch of the first refrigerant cycle, a fifth automatic switching valve and a first automatic regulating valve are provided on the rear end pipeline of the first refrigerant outlet of the heat exchanger, a second automatic switching valve, a third temperature sensor and a first mass flow meter are provided on the front end pipeline of the first refrigerant inlet of the centrifuge in the second branch of the first refrigerant cycle, and a third automatic switching valve, a fifth temperature sensor and a first pressure sensor are provided on the rear end pipeline of the first refrigerant outlet of the centrifuge.

3. The dual refrigerant circulation refrigeration system for a centrifuge according to claim 2, characterized in that: The second refrigerant cycle is provided with a sixth automatic switching valve at the liquid outlet of the second refrigerant storage tank, an eighth automatic switching valve and a second automatic regulating valve are provided in the first branch of the second refrigerant cycle near the liquid return port of the second refrigerant storage tank, a ninth automatic switching valve, a fourth temperature sensor and a second mass flow meter are provided on the front end pipeline of the second refrigerant inlet of the centrifuge on the second branch of the second refrigerant cycle, and a tenth automatic switching valve, a sixth temperature sensor and a second pressure sensor are provided on the rear end pipeline of the second refrigerant outlet of the centrifuge.

4. The dual refrigerant circulation refrigeration system for a centrifuge according to claim 3, characterized in that: The first temperature sensor and the first liquid level sensor are installed at the bottom of the first refrigerant storage tank, and the outlet pipeline at the bottom of the first refrigerant storage tank is installed with a drain valve, which is the thirteenth automatic switch valve; the second temperature sensor and the second liquid level sensor are installed at the bottom of the second refrigerant storage tank, and the outlet pipeline at the bottom of the second refrigerant storage tank is installed with a drain valve, which is the seventh automatic switch valve, and the top of the second refrigerant storage tank is installed with a flame-blocking breathing valve; The first circulation pump, the second circulation pump and the heat exchanger are respectively equipped with drain valves.

5. The dual refrigerant circulation refrigeration system for a centrifuge according to claim 4, characterized in that: The controller includes a central processing unit, a filter / amplifier circuit, an A / D conversion circuit, a D / A conversion circuit, a display screen and buttons; the first to sixth temperature sensors, the first / second mass flowmeters, the first / second pressure sensors, and the first / second liquid level sensors are all connected to the filter / amplifier circuit, the filter / amplifier circuit is connected to the A / D conversion circuit, and the A / D conversion circuit is connected to the central processing unit; the first / second automatic regulating valve is connected to the D / A conversion circuit, and the D / A conversion circuit is connected to the central processing unit; the first / second circulating pump, all automatic switch valves, and the refrigeration unit are connected to the central processing unit.

6. A control method for the centrifuge dual-refrigerant circulation refrigeration system according to claim 5, characterized in that: include: A. When the system operation instruction is to start the refrigeration cycle of the first refrigerant storage tank, enter step S11; B. When the system operation instruction is to start the refrigeration cycle of the second refrigerant storage tank, enter step S12; C. When the system operation instruction is to start the first refrigerant storage tank to cool the first temperature zone of the centrifuge, enter step S21; D. When the system operation instruction is to start the second refrigerant storage tank to cool the second temperature zone of the centrifuge, enter step S22; E. When the system operation instruction is to stop the second refrigerant storage tank from refrigerating the second temperature zone of the centrifuge, enter step S31; F. When the system operation instruction is to stop the first refrigerant storage tank from refrigerating the first temperature zone of the centrifuge, enter step S32; G. When the system operation instruction is to stop the refrigeration cycle of the second refrigerant storage tank, enter step S41; H. When the system operation instruction is to stop the refrigeration cycle of the first refrigerant storage tank, enter step S42.

7. The control method of the centrifuge dual refrigerant circulation refrigeration system according to claim 6, characterized in that: The step S11 specifically includes: opening the first automatic switch valve, the fourth automatic switch valve, and the fifth automatic switch valve, the first automatic regulating valve operates according to the preset first opening value, and the refrigeration unit is started; the first refrigerant in the first refrigerant storage tank returns to the first refrigerant storage tank after passing through the refrigeration unit, the first circulation pump, and the heat exchanger; The step S12 specifically includes: automatically detecting and determining whether the first temperature sensor in the first refrigerant storage tank reaches a preset temperature range, and if reached, opening the sixth automatic switch valve and the eighth automatic switch valve, the second automatic regulating valve operates according to the preset first opening value, and starting the second circulation pump; the second refrigerant medium in the second refrigerant storage tank is cooled by the second circulation pump and the heat exchanger and then returns to the second refrigerant storage tank.

8. The control method of the centrifuge dual refrigerant circulation refrigeration system according to claim 7, characterized in that: The step S21 specifically includes automatically detecting and judging that the step S11 is operating normally and the first temperature sensor reaches a preset temperature range, opening the second automatic switch valve and the third automatic switch valve, and starting the first circulation pump at a pump speed of the first set value ω. set1(51) Operation, the first automatic regulating valve operates according to the preset second opening value, and the real-time flow of the first mass flow meter is detected. If it reaches the preset flow range within the time length t1, it is determined that S21 operates normally; If the real-time pressure of the first pressure sensor P act(91) The first set pressure value P is reached within the set time period t2 set1(91) When the first pressure sensor real-time pressure P act(91) The second set pressure value P is reached within the set time period t3 set2(91) When P set2(91) >P set1(91) ; The step S22 specifically includes: automatically detecting and judging that step S12 operates normally and the second temperature sensor reaches a preset temperature range, opening the ninth automatic switch valve and the tenth automatic switch valve, and the second automatic regulating valve operates according to the preset second opening value, and detecting the real-time flow of the second mass flow meter. If it reaches the preset flow range within the time t4, it is determined that S22 operates normally; when S22 operates normally, on the premise of ensuring that the flow of the second mass flow meter is within the preset flow range: When the fourth temperature sensor real-time temperature T act(84) Higher than the first set value T set1(84) When the real-time temperature T act(84) Reduce to the first set value T set1(84) -T1, the opening value of the second automatic regulating valve is gradually adjusted according to the output result of PID control, the gradual adjustment speed is less than V2, V1>V2, T1 is a positive number; When the fourth temperature sensor real-time temperature T act(84) Higher than the second set value T set2(84) When T, the opening value of the first automatic regulating valve is gradually adjusted according to the output result of PID control, and the gradual adjustment speed is less than V3; set2(84) >T set1(84) ; When the fourth temperature sensor real-time temperature T act(84) Lower than the third set value T set3(84) When the real-time temperature T act(84) Increase to the third setting value T set3(84) +T2, the opening value of the second automatic regulating valve is gradually adjusted according to the output result of PID control, and the gradual adjustment speed is less than V5; V4>V5, T set2(84) >T set1(84) >T set3(84) , T2 is a positive number; When the second temperature sensor real-time temperature T act(82) Higher than the first set value T set1(82) When the opening value of the first automatic regulating valve is gradually adjusted according to the output result of the PID control, and the increase in the opening value will not cause the flow rate of the first mass flow meter to be lower than the lower limit warning value of the set range, the gradual adjustment speed is less than V6, and at the same time, the pump speed of the first circulation pump is increased to the second set value ω set2(51) ; When the real-time temperature T act(82) Down to the first set value T set1(82) -T3, the opening value of the first automatic regulating valve is gradually adjusted according to the output result of the PID control, and the gradual adjustment speed is less than V7, and the pump speed of the first circulation pump is restored to the first set value ω set1(51) ; V6>V7,ω set2(51) >ω set1(51) , T3 is a positive number; When the second pressure sensor real-time pressure P act(92 ) reaches the first set pressure value P within the set time period t1 set1(92) When the alarm is triggered; When the second pressure sensor real-time pressure P act(92) The second set pressure value P is reached within the set time period t2 set2(92) When P set2(92) >P set1(92) .

9. The control method of the centrifuge dual refrigerant circulation refrigeration system according to claim 8, characterized in that: The step S31 specifically includes: the second automatic regulating valve operates according to the preset third opening value, and the ninth automatic switch valve and the tenth automatic switch valve are closed; The step S32 specifically includes: the first automatic regulating valve operates according to the preset third opening value, the first circulating pump is stopped, and the second automatic switch valve and the third automatic switch valve are closed; The step S41 specifically includes stopping the second circulation pump, closing the sixth automatic switch valve, the eighth automatic switch valve and the second automatic regulating valve; The specific step of S42 includes stopping the refrigeration unit, closing the first automatic switch valve, the fourth automatic switch valve, the fifth automatic switch valve and the first automatic regulating valve.

10. The control method of the centrifuge dual refrigerant circulation refrigeration system according to claim 8, characterized in that: The output result of the PID control is the calculation result based on the difference between the current real-time temperature and the set temperature, which is expressed as follows: Among them, Q(t) represents the output result of PID control, K p , K i , K d They represent the proportional coefficient, integral coefficient, and differential coefficient of PID control respectively, C represents the compensation term, and T set Represents the set temperature, T act represents the real-time temperature, E(t) represents the real-time temperature difference; for different set temperatures T set , pre-configured with parameter groups K matching each cooling stage p , K i , K d and C.

Images