PCR (Polymerase Chain Reaction) instrument for food microorganism detection

Abstract

The invention discloses a PCR instrument for food microorganism detection, and aims to solve the problems of unstable temperature control, low temperature rising and falling speed, low temperature control precision and the like of an existing PCR instrument. The PCR instrument comprises a PCR instrument main body, a thermostatic bath, a water tank, an electric heating plate, a circulating pump, a control panel and a temperature sensing probe. Through liquid medium heating and circulating pump driving, water flow circulation in the liquid guide groove is achieved, and uniform temperature distribution is ensured. The system adopts a multi-point temperature monitoring and PID control algorithm, the power of the electric heating plate is accurately adjusted, the system has the functions of rapid heating and cooling, and the temperature control precision and efficiency are remarkably improved. In addition, the PCR instrument is provided with an intelligent fault detection and alarm system, temperature abnormity or water circulation faults can be automatically processed, operation is easy and convenient, and the automation degree is high. The PCR instrument is particularly suitable for the field of food microorganism detection, provides a stable, rapid and efficient PCR reaction environment, and ensures the accuracy and reliability of a detection result.

Description

Technical Field

[0001] The invention relates to the technical field of food detection, in particular to a PCR instrument for food microorganism detection. Background Art

[0002] PCR (Polymerase Chain Reaction) is an important molecular biology technique used to amplify specific DNA fragments. PCR technology is widely used in gene sequencing, gene testing, disease diagnosis, and microbial testing. In the field of food safety, PCR technology can quickly and accurately detect microorganisms (such as bacteria, viruses, etc.) in food, thereby effectively controlling food hygiene and quality issues.

[0003] Traditional PCR instruments control the temperature of the reaction solution by air heating. The key steps of the PCR process include DNA denaturation, annealing, and extension, and each step requires precise temperature control. Therefore, temperature stability and uniformity are crucial to the success of the PCR reaction. However, traditional air-heated PCR instruments have some disadvantages:

[0004] Unstable temperature control: Since the specific heat capacity of air is small and the heat conduction efficiency in air is low, the PCR instrument is easily affected by the external ambient temperature, resulting in temperature fluctuations, which in turn affects the accuracy of the experimental results.

[0005] Slow heating and cooling speed: The thermal conductivity of air as a medium is poor, which leads to a slow heating and cooling process of the reaction liquid, prolonging the experimental time and reducing efficiency.

[0006] Low temperature control accuracy: When the PCR instrument is frequently opened or closed, the heat of the air tends to be lost quickly and the temperature recovers slowly, affecting the accuracy and reliability of the PCR reaction.

[0007] In order to solve these problems, some PCR instruments that use liquid media heating have appeared in recent years. Liquid media have large specific heat capacity and high heat transfer efficiency, and can better maintain the temperature stability of the reaction solution. By controlling the temperature through liquid circulation, the PCR instrument can provide more precise temperature control and can effectively speed up the heating and cooling process. However, the existing liquid medium temperature control PCR instrument still has some shortcomings in design:

[0008] Uneven distribution of water flow temperature: Although the liquid has good thermal conductivity, there may be local temperature unevenness in the liquid conduction groove, resulting in inconsistent experimental results.

[0009] Insufficient flexibility in temperature control: Most liquid heating systems cannot flexibly adjust the heating and cooling rates according to different experimental requirements, which limits the application scope of PCR instruments.

[0010] The system is not highly intelligent: Traditional liquid temperature control systems rely on simple temperature difference control and lack the ability to respond to complex temperature fluctuations and automatic adjustment functions, which affects the accuracy and efficiency of temperature control.

[0011] Therefore, it is of great significance to design a liquid temperature-controlled PCR instrument that can automatically adjust the temperature, improve the temperature control accuracy, and quickly heat and cool. This PCR instrument can not only improve the accuracy and efficiency of food microbiological detection, but also expand its application in other molecular biology fields. Summary of the invention

[0012] The purpose of the present invention is to provide a PCR instrument for food microorganism detection in view of the shortcomings of the prior art, so as to solve the problems raised in the background technology.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] A PCR instrument for food microorganism detection comprises a PCR instrument body, a constant temperature bath is provided at the central position of the PCR instrument body, liquid guide grooves are provided on the outer walls of both sides of the constant temperature bath, a liquid discharge port and a liquid inlet which penetrate the PCR instrument body are respectively provided on the inner walls of the two liquid guide grooves, a water tank is fixedly provided on the outer wall of one side of the PCR instrument body, a water inlet and a water filling port are respectively provided at both ends of the water tank, the liquid discharge port is communicated with the water inlet through a pipeline, the liquid inlet is communicated with the water filling port through a pipeline, a circulating pump is provided inside the water tank, the circulating pump comprises an input end and an output end, the input end of the circulating pump is located inside the water tank, the output end of the circulating pump is communicated with the water filling port, an electric heating plate is fixedly provided on the inner wall of the bottom of the water tank, a culture platform is provided inside the constant temperature bath, a culture tray is provided at the central position of the culture platform, first flow guide ports which are equidistantly distributed and penetrate the outer walls of both ends of the culture platform are provided, and second flow guide ports which are equidistantly distributed and penetrate the outer wall of the culture tray are provided.

[0015] Preferably, the second flow guide port is communicated with the first flow guide port, and the first flow guide port is communicated with two liquid guide grooves respectively.

[0016] Preferably, first taking grooves are opened on both inner walls of the liquid conducting groove, and second taking grooves are opened on both outer walls of the culture platform. The first taking groove and the second taking groove are connected to each other, so that the culture platform can be easily taken out from the inside of the liquid conducting groove through the first taking groove and the second taking groove.

[0017] Preferably, the top outer wall of the culture dish is provided with culture holes distributed at equal distances, and the culture holes serve as spaces for culturing DNA polymerase.

[0018] Preferably, a supply port is opened at one end of the top of the water tank, an externally threaded pipe is fixedly provided on the inner wall of the supply port, a screw cover is screwed on the outer wall of the externally threaded pipe, and water is conveniently supplied to the water tank through the supply port.

[0019] Preferably, a temperature sensing probe is provided inside the constant temperature bath, a control panel is provided on the side of the PCR instrument body away from the water tank, a control knob is provided on one side of the PCR instrument body, the control knob is located at the bottom of the control panel, the temperature sensing probe is data-connected to the control panel, and the circulation pump and the electric heating plate are control-connected to the control panel via the control knob.

[0020] Preferably, a cover plate is movably connected to one side of the top of the PCR instrument body via a hinge, and a handle is fixedly provided on the top outer wall of the cover plate.

[0021] Preferably, the electric heating plate (21) is used to heat the water in the water tank (13); the temperature sensing probe is used to monitor the temperature in the thermostatic bath (4) in real time; the control panel (2) and the control knob (3) are used to adjust the temperature, and the control panel automatically adjusts the power output of the electric heating plate according to the following formula:

[0022] P=k×(T 设定 -T 实际 )

[0023] in:

[0024] P is the power of the heating plate (unit: watt, W); T 设定 To set the temperature;

[0025] T 实际 The actual temperature measured by the temperature probe;

[0026] k is the temperature adjustment coefficient, which is used to control the rate of power response of the heating plate;

[0027] When T 实际 =T 设定 , the power of the heating plate automatically drops to zero to achieve a constant temperature state.

[0028] Preferably, the circulation pump (19) is used to transport water from the water tank (13) to the liquid guide groove (5); the control panel (2) is connected to the temperature sensing probe to automatically adjust the water flow rate, and the control formula is:

[0029]

[0030] Where: Q is the water flow rate (unit: liter / second, L / s); C is the system flow coefficient;

[0031] ΔT is the temperature change of water in the liquid-conducting groove (unit: degrees Celsius, ℃);

[0032] Δt is the time interval (unit: seconds, s).

[0033] Preferably: the control panel is used to adjust the power of the heating plate (21) according to temperature feedback;

[0034] The temperature control formula is:

[0035]

[0036] Where: T(t) is the water temperature after time t (unit: Celsius, ℃); T0 is the initial water temperature (unit: Celsius, ℃); P max is the maximum power of the heating plate (unit: watt, W); C w is the specific heat capacity of water, about 4186 J / m w is the mass of water (unit: kilogram, kg); t is the heating time (unit: second, s).

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The electric heating plate is controlled by the control panel and the control knob to heat the water, and the water is sucked in through the input end of the circulation pump. The circulation pump passes the water through the water inlet through the pipe and into the liquid inlet. The water in the liquid inlet enters the liquid guide groove. The culture platform and the culture plate are located inside the liquid guide groove. The heated water passes through the first guide port and the second guide port, and the culture platform and the culture plate are heated to the specified temperature at the same time. The water in the liquid guide groove passes through the pipe from the water inlet through the drain port to enter the water tank for water circulation. By heating the water and circulating it, the temperature of the culture platform and the first guide port is controlled. The specific heat capacity of water is large, which will not cause temperature loss in the liquid guide groove, and the temperature control stability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a schematic diagram of the structure of the present invention;

[0041] Figure 2 It is a schematic diagram of the structure of the present invention;

[0042] Figure 3 It is a schematic diagram of the three-dimensional structure of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of the culture platform of the present invention;

[0044] Figure 5This is a schematic diagram of the structure of the culture dish of the present invention;

[0045] Figure 6 It is a schematic diagram of the cross-sectional structure of the water tank of the present invention.

[0046] Description of reference numerals:

[0047] 1PCR instrument body, 2control panel, 3control knob, 4constant temperature bath, 5liquid guide tank, 6first taking tank, 7culture platform, 8second taking tank, 9culture plate, 10culture well, 11first flow guide port, 12second flow guide port, 13water tank, 14drain port, 15liquid inlet, 16water inlet, 17water adding port, 19circulating pump, 21electric heating plate, 22supply port, 23cover plate, 24handle. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Embodiment 1

[0050] Refer to the instruction manual Figure 1-6 A PCR instrument for food microorganism detection includes a PCR instrument body 1, a constant temperature tank 4 is opened at the central position of the PCR instrument body 1, and liquid guide grooves 5 are opened on the outer walls of both sides of the constant temperature tank 4. The inner walls of the two liquid guide grooves 5 are respectively opened with a liquid discharge port 14 and a liquid inlet 15 that penetrate the PCR instrument body 1. A water tank 13 is fixedly provided on the outer wall of one side of the PCR instrument body 1, and a water inlet 16 and a water filling port 17 are respectively opened at both ends of the water tank 13. The liquid discharge port 14 is connected to the water inlet 16 through a pipeline, and the liquid inlet 15 is connected to the water filling port 17 through a pipeline. A circulation pump 19 is provided inside the water tank 13, and the circulation pump 19 includes an input end and an output end. The input end of the circulation pump 19 is located inside the water tank 13, and the output end of the circulation pump 19 is connected to the water inlet 17. An electric heating plate 21 is fixedly provided on the inner wall of the bottom of the water tank 13. A culture table 7 is provided inside the constant temperature bath 4, and a culture tray 9 is provided at the central position of the culture table 7. The outer walls at both ends of the culture table 7 are provided with first guide ports 11 that are equidistantly distributed and penetrate through the outer wall of the culture tray 9. The outer wall of the culture tray 9 is provided with second guide ports 12 that are equidistantly distributed and penetrate through the outer wall.

[0051] Embodiment 2

[0052] Based on the first embodiment, the second flow guide port 12 is connected to the first flow guide port 11, and the first flow guide port 11 is respectively connected to the two liquid guide grooves 5. The inner walls on both sides of the liquid guide groove 5 are provided with first taking grooves 6, and the outer walls on both sides of the culture platform 7 are provided with second taking grooves 8. The first taking groove 6 and the second taking groove 8 are connected to each other, and the culture platform 7 is conveniently taken out from the inside of the liquid guide groove 5 through the first taking groove 6 and the second taking groove 8. The top outer wall of the culture plate 9 is provided with culture holes 10 distributed at equal distances, and the culture holes 10 serve as a space for culturing DNA polymerase.

[0053] Embodiment 3

[0054] Based on the first embodiment, a supply port 22 is opened at one end of the top of the water tank 13, and an external threaded tube is fixedly provided on the inner wall of the supply port 22. A screw cover is screwed on the outer wall of the external threaded tube, so that water can be easily supplied to the water tank 13 through the supply port 22. A cover plate 23 is movably connected to one side of the top of the PCR instrument body 1 through a hinge, and a handle 24 is fixedly provided on the top outer wall of the cover plate 23.

[0055] Embodiment 4

[0056] Based on the first embodiment, a temperature sensing probe is provided inside the constant temperature bath 4, a control panel 2 is provided on the side of the PCR instrument body 1 away from the water tank 13, a control knob 3 is provided on one side of the PCR instrument body 1, and the control knob 3 is located at the bottom of the control panel 2. The temperature sensing probe is data-connected with the control panel 2, and the circulating pump 19 and the electric heating plate 21 are control-connected with the control panel 2 through the control knob 3.

[0057] Working principle of the present invention:

[0058] Refer to the instruction manual Figure 1-6When in use, first add clean water into the water tank 13 through the replenishment port 22, control the electric heating plate 21 to heat the water through the control panel 2 and the control knob 3, and inhale the water through the input end of the circulation pump 19. The circulation pump 19 passes the water through the water inlet 17 and the pipeline into the liquid inlet 15. The water in the liquid inlet 15 enters the liquid guide groove 5. The culture platform 7 and the culture plate 9 are located inside the liquid guide groove 5. The heated water passes through the first guide port 11 and the second guide port 12, and heats the culture platform 7 and the culture plate 9 to the specified temperature at the same time. The DNA polymerase to be tested is dripped into the culture hole 10 for cultivation, and the cover plate 23 is closed. The water in the liquid conducting groove 5 enters the water tank 13 from the water inlet 16 through the pipe via the drain port 14 for water circulation. The water is heated and circulated to control the temperature of the culture platform 7 and the first guide port 11. The specific heat capacity of water is large, and when the cover 23 is opened, it will not cause the liquid conducting groove 5 to lose temperature, and the temperature control stability is good. The water entering the water tank 13 is heated again, and the temperature of the liquid conducting groove 5 is circulated and controlled, and the use effect is good. After the DNA polymerase in the culture hole 10 is cultivated, the cover 23 is opened by pulling the handle 24, and the culture platform 7 is taken out through the first taking groove 6 and the second taking groove 8, and the cultivated DNA polymerase is subjected to the next step of detection.

[0059] Embodiment five:

[0060] Basic temperature control system:

[0061] P=k×(T 设定 -T 实际 )

[0062] Where: P is the power of the heating plate (unit: watt, W); T 设定 is the set temperature; T 实际 The actual temperature measured by the temperature probe;

[0063] k is the temperature adjustment coefficient, which is used to control the rate of power response of the heating plate;

[0064] When T 实际 =T 设定 , the power of the heating plate automatically drops to zero to achieve a constant temperature state.

[0065] The circulation pump (19) is used to transport water from the water tank (13) to the liquid guide groove (5); the control panel (2) is connected to the temperature sensor probe to automatically adjust the water flow rate, and the control formula is:

[0066]

[0067] Where: Q is the water flow rate (unit: liter / second, L / s); C is the system flow coefficient;

[0068] ΔT is the temperature change of water in the liquid-conducting groove (unit: degrees Celsius, ℃);

[0069] Δt is the time interval (unit: seconds, s).

[0070] The control panel is used to adjust the power of the heating plate (21) according to temperature feedback;

[0071] The temperature control formula is:

[0072]

[0073] Where: T(t) is the water temperature after time t (unit: Celsius, ℃); T0 is the initial water temperature (unit: Celsius, ℃); P max is the maximum power of the heating plate (unit: watt, W); C w is the specific heat capacity of water, about 4186 J / m w is the mass of water (unit: kilogram, kg); t is the heating time (unit: second, s).

[0074] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

[0075] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A PCR instrument for food microorganism detection, comprising a PCR instrument body (1), characterized in that: A constant temperature tank (4) is provided at the central position of the PCR instrument body (1), and liquid guide grooves (5) are provided on the outer walls of both sides of the constant temperature tank (4). The inner walls of the two liquid guide grooves (5) are respectively provided with a liquid discharge port (14) and a liquid inlet (15) that penetrate the PCR instrument body (1). A water tank (13) is fixedly provided on the outer wall of one side of the PCR instrument body (1), and a water inlet (16) and a water filling port (17) are respectively provided at the two ends of the water tank (13). The liquid discharge port (14) is connected to the water inlet (16) through a pipeline, and the liquid inlet (15) is connected to the water filling port (17) through a pipeline. The interior of the water tank (13) is provided with a A circulation pump (19) is provided, the circulation pump (19) comprising an input end and an output end, the input end of the circulation pump (19) is located inside a water tank (13), the output end of the circulation pump (19) is connected to a water inlet (17), an electric heating plate (21) is fixedly provided on the inner wall of the bottom of the water tank (13), a culture platform (7) is provided inside the thermostatic bath (4), a culture tray (9) is provided at the central position of the culture platform (7), first flow guide ports (11) which are equidistantly distributed and penetrate the outer wall of both ends of the culture platform (7), and second flow guide ports (12) which are equidistantly distributed and penetrate the outer wall of the culture tray (9) are provided.

2. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The second flow guide port (12) is in communication with the first flow guide port (11), and the first flow guide port (11) is in communication with two liquid guide grooves (5) respectively.

3. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The inner walls of both sides of the liquid-conducting groove (5) are provided with first taking grooves (6), and the outer walls of both sides of the culture platform (7) are provided with second taking grooves (8), and the first taking groove (6) and the second taking groove (8) are connected to each other.

4. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The top outer wall of the culture dish (9) is provided with culture holes (10) distributed at equal distances.

5. A PCR instrument for food microorganism detection according to claim 1, characterized in that: A supply port (22) is provided at one end of the top of the water tank (13), an externally threaded pipe is fixedly provided on the inner wall of the supply port (22), and a screw cap is screwed on the outer wall of the externally threaded pipe.

6. A PCR instrument for food microorganism detection according to claim 1, characterized in that: A temperature sensing probe is provided inside the thermostatic bath (4); a control panel (2) is provided on the side of the PCR instrument body (1) away from the water tank (13); a control knob (3) is provided on one side of the PCR instrument body (1); the control knob (3) is located at the bottom of the control panel (2); the temperature sensing probe is data-connected to the control panel (2); and the circulation pump (19) and the electric heating plate (21) are control-connected to the control panel (2) via the control knob (3).

7. A PCR instrument for food microorganism detection according to claim 1, characterized in that: A cover plate (23) is movably connected to one side of the top of the PCR instrument body (1) via a hinge, and a handle (24) is fixedly provided on the top outer wall of the cover plate (23).

8. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The electric heating plate (21) is used to heat the water in the water tank (13); the temperature sensor is used to monitor the temperature in the thermostatic bath (4) in real time; the control panel (2) and the control knob (3) are used to adjust the temperature, and the control panel automatically adjusts the power output of the electric heating plate according to the following formula: P=k×(T 设定 -T 实际 ) Where: P is the power of the heating plate (unit: watt, W); T 设定 is the set temperature; T 实际 The actual temperature measured by the temperature probe; k is the temperature adjustment coefficient, which is used to control the rate of power response of the heating plate; When T 实际 =T 设定 , the power of the heating plate automatically drops to zero to achieve a constant temperature state.

9. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The circulation pump (19) is used to transport water from the water tank (13) to the liquid guide groove (5); the control panel (2) is connected to the temperature sensor probe to automatically adjust the water flow rate, and the control formula is: Where: Q is the water flow rate (unit: liter / second, L / s); C is the system flow coefficient; ΔT is the temperature change of water in the liquid-conducting groove (unit: degrees Celsius, ℃); Δt is the time interval (unit: seconds, s).

10. A PCR instrument for food microorganism detection according to claim 1, characterized in that: The control panel is used to adjust the power of the heating plate (21) according to temperature feedback; The temperature control formula is: Where: T ( t ) is the water temperature after time t (unit: Celsius, ℃); T0 is the initial water temperature (unit: Celsius, ℃); P max is the maximum power of the heating plate (unit: watt, W); C w is the specific heat capacity of water, about 4186 J / m w is the mass of water (unit: kilogram, kg); t is the heating time (unit: second, s).

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