Food heavy metal detector and use method thereof

Abstract

The invention relates to the technical field of food detection, and discloses a food heavy metal detector and a use method thereof.The food heavy metal detector comprises a rack, a detection unit is installed on the rack, a test tube rack is rotationally connected to the interior of the rack, a plurality of detection tubes are installed in the test tube rack, and a composite discharging assembly is arranged in the rack; the composite discharging assembly comprises two micromotors which are symmetrically installed on the outer surface of the rack, the test tube rack rotates, the test tube rack rotates and vibrates at the same time through a telescopic rod under the action of a balancing weight, so that the discharging purpose is achieved, through the synergistic effect of rotation and vibration, the discharging efficiency is improved, and the working efficiency is improved. The liquid in the detection tube can be more effectively discharged, the liquid can be gathered towards the bottom of the detection tube by rotation under the action of centrifugal force, the surface tension of the liquid and the possible local attachment state can be further broken by vibration, the liquid can flow out more smoothly, and the discharging efficiency and thoroughness are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of food detection, and specifically to a food heavy metal detector and its usage method. Background Art

[0002] A food heavy metal detector is a professional device for detecting the heavy metal content in food. Its working principle is based on a liquid combination color development experiment. A food sample is mixed with a specific detection reagent, causing heavy metal ions to undergo a chemical reaction with the reagent to form a compound with a specific color. By comparing the color change with a standard color card or using an optical sensor for quantitative analysis, the heavy metal content in the food can be determined. This detector is easy to operate, has a fast detection speed, can detect a variety of common heavy metals, provides strong support for ensuring food safety, and is widely used in fields such as food production and detection.

[0003] In a Chinese patent with the patent publication number CN116448748A, a food heavy metal detector is disclosed, which includes two side plates and a bottom plate fixed between the two side plates. A nut pair that moves in the horizontal direction and a cross plate that moves in the front-rear direction are provided between the two side plates, and multiple test tubes are installed on the cross plate. In this application, after the food heavy metal detection is completed, the electric push rod three drives the movement of the bending arm. Under the action of the through groove and the moving pin, the cross plate drives the test tubes to move backward. Under the action of the gear, the tooth block, the prism, and the rotating sleeve, the cam rotates upward, lifting the lifting plate, so that the moving cover covers the bottom of the test tube, the stopper abuts against the stop rod, and the liquid inside the test tube is discharged through the liquid outlet pipe. The electric push rod two drives the lifting block to move downward to block the top of the test tube. Then, under the action of the hot air blower and the pump two, the test tube can be cleaned and dried. Compared with the manual cleaning method, the automation degree is higher, and the labor amount of the staff can be effectively reduced.

[0004] However, the equipment and the prior art in the cited document still have the following defects in specific use:

[0005] 1. During the liquid drainage process in the cited document, the electric push rod three is started to drive the separation of the blocking block from the inner wall of the bottom of the test tube, so that the internal liquid enters the moving cover and is discharged. However, in actual operation, the blocking block continuously separates and gathers, which will cause the blocking block to gradually wear. As time goes by and the number of uses increases, the wear of the blocking block will reduce the sealing performance between it and the inner wall of the bottom of the test tube.

[0006] When the sealing performance is poor, on the one hand, leakage will occur during the liquid discharge process, resulting in the liquid not being able to enter the moving cover completely smoothly, affecting the thoroughness of liquid discharge. On the other hand, since the internal space of the test tube is relatively large while the size of the plugging block is small, when the plugging block moves, the liquid inside the test tube will erupt under the action of pressure change. This eruption will not only cause some liquid to fail to enter the moving cover, resulting in liquid residue, but also pollute the surrounding environment. For example, if the liquid being detected contains heavy metals, spraying it into the surrounding environment may pose a potential threat to the laboratory environment and the health of personnel.

[0007] In addition, the instability of this liquid discharge method will also affect the subsequent cleaning and drying effects. Liquid residue will make the cleaning incomplete, thereby affecting the efficiency and quality of drying, unable to meet the requirements of high-efficiency and accurate detection, and also increasing the difficulty of subsequent maintenance and cleaning.

[0008] 2. There are obvious defects in the equipment in the cited document when cleaning the test tube. In actual operation, it uses a water pump to drain water, cleans the test tube through a series of pipelines, then uses a hot air blower to dry the inside of the test tube, and at the same time uses a brush to assist in cleaning. However, food liquids often have relatively viscous characteristics, which makes it difficult to completely remove the viscous liquids attached to the inner wall of the test tube simply by flushing with water.

[0009] During the flushing process, water may only wash away some relatively easily detachable stains, and for those residual substances with strong viscosity, the water flow cannot effectively carry them away. Although the hot air blower can dry the test tube, when the viscous liquid has not been completely removed, there will still be residual substances attached to the inner wall of the test tube after drying, affecting the subsequent detection accuracy.

[0010] In addition, the cleaning effect of the brush is also relatively limited. On the one hand, the brush can only clean some areas of the inner wall of the test tube and it is difficult to reach some corners and fine parts. On the other hand, during the brushing process, the brush rubs against the inner wall of the test tube frequently, which is easy to cause damage to the inner wall of the test tube. Once scratches or abrasions appear on the inner wall of the test tube, it will not only affect the service life of the test tube, but may also have adverse effects such as adsorption on the subsequent test samples, resulting in deviation of the test results. Therefore, this cleaning method is difficult to meet the high requirements of the food heavy metal detector for the cleanliness of the test tube.

[0011] For this reason, the present invention proposes a food heavy metal detector and its use method. Summary of the Invention

[0012] The purpose of the present invention is to provide a food heavy metal detector and its use method to solve the problems raised in the above background technology.

[0013] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a food heavy metal detector, comprising a frame, a detection unit is installed on the frame, a test tube rack is rotatably connected inside the frame, a plurality of detection tubes are installed inside the test tube rack, a composite discharge assembly is arranged inside the frame, the composite discharge assembly comprises two micromotors, the two micromotors are symmetrically installed on the outer surface of the frame, the output shaft of each micromotor is symmetrically fixedly connected with a counterweight block, a plurality of springs are installed on the inner wall of the frame, a resistance plate is installed on the top of the spring, a plurality of connecting seats 1 are installed on the top of the resistance plate, a plurality of connecting seats 2 are installed on the bottom of the test tube rack, and a telescopic rod is rotatably connected between each connecting seat 1 and the connecting seat 2.

[0014] Preferably, the counterweight block is in the shape of a circular notch.

[0015] Preferably, a limiting shaft is fixedly connected to the bottom of the inner cavity of the frame, and the abutment plate is slidably connected to the outer surface of the limiting shaft.

[0016] Preferably, a synchronous belt is provided between the output shaft of the micromotor and the detection tube for transmission connection.

[0017] Preferably, a collection box is installed at the bottom of the inner cavity of the frame.

[0018] Preferably, a double spiral cleaning assembly is provided inside the frame, and the double spiral cleaning assembly includes a mounting plate fixedly connected to the inside of the frame, a plurality of spiral interfaces are installed at the bottom of the mounting plate, an outer edge of the spiral interface is fixedly connected to an outer spiral strip, an inner edge of the spiral interface is fixedly connected to an inner spiral strip, a water pump is installed on the outer surface of the frame, and an air pump is installed on the outer surface of the frame and on the side away from the water pump.

[0019] Preferably, two groups of connecting pipes are arranged outside the frame, wherein one group of connecting pipes is interconnected with the water pump and the inner spiral strip, and the other group of connecting pipes is interconnected with the air pump and the outer spiral strip.

[0020] Preferably, the thread directions of the outer spiral strip and the inner spiral strip are opposite, and the thread shapes of the outer spiral strip and the inner spiral strip are also opposite.

[0021] The method of using the food heavy metal detector includes the following steps:

[0022] Step 1: Preheat the detector first. The calibration wavelength depends on the type of heavy metal to be detected. Turn on the power and turn on the switch. After preheating is completed, take 5ml of heavy metal standard solution and inject it into the cuvette and put it into the detection tank. Select the corresponding detection item and calibration wavelength according to the instrument prompts;

[0023] Step 2: Stir the liquid sample evenly, add nitric acid for digestion. The digestion temperature is 180 - 220 °C and the time is 30 - 60 minutes. After digestion, cool it and make up the volume to 50 ml to obtain the sample solution to be measured.

[0024] Step 3: The dosage of the color reagent is 1 - 5 ml, the color reaction time is 5 - 30 minutes, and the color reaction temperature is 25 °C. Take 5 ml of the sample solution to be measured and inject it into a colorimetric cell, add the color reagent and shake well.

[0025] Step 4: The detection wavelength is the same as the calibration wavelength. Put the colorimetric cell after color development into the detection slot, select the corresponding item and wavelength to start the detection. The instrument measures the absorbance and displays the result according to the calibration curve for the acid content. Record and judge whether it exceeds the standard. If abnormal, retest or check and calibrate the instrument.

[0026] Step 5: Take out the colorimetric cell, rinse it, dry it, turn off the power of the instrument and unplug the plug, clean the instrument and the working area, and properly store the instrument and reagents.

[0027] Preferably, in Step 1, the preheating time is thirty minutes.

[0028] Preferably, a position sensor is installed on the inner wall of the frame, and the position sensor is used to detect the position of the detection tube.

[0029] Preferably, the diameter of the output shaft of the micro-motor is larger than the diameter of the test tube rack.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. The present invention rotates the test tube rack and, under the action of the counterweight block, makes the test tube rack vibrate while rotating through the telescopic rod, so as to achieve the purpose of discharging materials. Through the synergistic effect of rotation and vibration, it can more effectively promote the liquid in the detection tube to be discharged. Rotation can utilize the centrifugal force to make the liquid gather at the bottom of the detection tube, while vibration can further break the surface tension of the liquid and the possible local adhesion state, making the liquid flow out more smoothly, improving the efficiency and thoroughness of discharging materials.

[0032] Compared with the prior art, the structural design of the present invention is more reasonable and efficient. In the prior art, during the liquid discharging process, the liquid is discharged by driving the sealing block to separate from the inner wall of the bottom of the test tube through an electric push rod, which is prone to problems such as wear of the sealing block, liquid leakage and spraying, affecting the liquid discharging effect and subsequent cleaning and drying. However, the present invention, through the cooperation of the rotation and vibration of the test tube rack, avoids the wear problem caused by the frequent action of the sealing block, fundamentally eliminates the risks of liquid leakage and spraying caused by the decline of the sealing performance, ensures the stability and reliability of the liquid discharging process, and provides a good foundation for subsequent cleaning and drying work.

[0033] Among them: The telescopic design of the telescopic rod and the elastic connection coupling between components into a whole enable the force received by the test tubes to be effectively buffered and dispersed during the rotation and vibration of the test tube rack. This elastic connection method can avoid damage to the test tubes caused by rigid collision or excessive force, extend the service life of the test tubes, reduce the maintenance cost of the equipment, and at the same time ensure the continuity and stability of the testing work.

[0034] Among them: During the discharging process, there is a problem that the liquid in the cited document is prone to overflow and pollution. However, the composite discharging component of the present invention collects the discharged materials through the collection box and will not overflow. When the liquid in the test tube is discharged, the collection box can timely receive and hold the liquid, avoiding the liquid from spraying into the surrounding environment and effectively preventing potential threats to the laboratory environment and personnel health. This design not only meets the environmental protection requirements, but also ensures the safety and hygiene of the laboratory, providing a clean and safe environment for the testing work.

[0035] Among them: During the rotation of the counterweight block in the shape of a circular notch, its center of gravity is relatively evenly distributed. When the micro-motor drives the counterweight block to rotate, it can more smoothly generate centrifugal force and vibration effects. This stable rotation can ensure that the test tube rack maintains a relatively stable motion state during rotation and vibration, which is beneficial to the uniform distribution and smooth discharge of the liquid in the test tubes.

[0036] Among them: The structure of the present invention is relatively simple and easy to implement. Compared with the complex liquid discharging structure of the prior art, through a clever design, the present invention realizes efficient discharging, cleaning and drying functions with fewer components. At the same time, there are fewer force transmission links, reducing various problems that may be caused by force loss and unstable transmission, improving the overall performance and reliability of the equipment. This simple and efficient design not only reduces the manufacturing cost of the equipment, but also facilitates the operation and maintenance of the equipment, and is more conducive to popularization and application in actual production and testing work.

[0037] 2. During the cleaning process of the present invention, first, a water pump is used to transport water through a connecting pipe into the spiral interface, and under the action of the internal spiral strip, a spiral fluid is formed. This spiral fluid has unique cleaning advantages. It can form a continuous and uniform scouring force along the inner wall of the test tube. Compared with the traditional direct water flushing method, the spiral fluid can more effectively cover all parts of the inner wall of the test tube, including some corners and fine parts. This enables even relatively viscous food liquid residues to be gradually peeled off and carried away under the strong scouring of the spiral fluid, greatly improving the thoroughness of cleaning. Subsequently, the water pump is turned off and the air pump is turned on. The air pump forms a spiral air flow through the connecting pipe under the action of the outer spiral strip to perform secondary cleaning and drying on the inside of the test tube. The spiral air flow can not only further remove the remaining water stains and tiny impurities, but also use the rapid flow of the air flow to carry away the moisture and accelerate the drying process, ensuring that the inner wall of the test tube dries quickly, providing a clean and dry environment for subsequent detection work, and effectively avoiding the influence of residual substances on the detection results.

[0038] Among them: the thread directions of the outer spiral strip and the inner spiral strip are opposite. When the spiral fluid and the spiral air flow are formed under the action of the inner and outer spiral strips respectively, due to the opposite thread directions, their flow directions inside the test tube are also opposite. In this way, when the spiral fluid scours the inner wall of the test tube downward, the spiral air flow can act on the inner wall of the test tube from the opposite direction for secondary action, forming a cross-type cleaning and drying effect. This cross-action can cover the inner wall of the test tube more comprehensively, avoiding cleaning dead corners and further improving the quality of cleaning and drying. At the same time, the opposite thread directions can also make the fluid and the air flow form a mutually restraining force inside the test tube, reducing the shaking or instability of the test tube that may be caused by the action of a single-direction force, ensuring the smooth progress of the cleaning and drying process.

[0039] Among them: the water is set at the internal spiral strip instead of the outer spiral strip, and the air flow is set at the outer spiral strip instead of the internal spiral strip. First, when the water forms a spiral fluid at the internal spiral strip, it can act more directly on the residual substances attached to the inner wall of the test tube. Because the internal spiral strip is closer to the center of the test tube, the water flow can scour the residual substances from the inside to the outside, making it easier to peel them off. And when the air flow is set at the outer spiral strip, during secondary cleaning and drying, the spiral air flow can blow on the inner wall of the test tube from the outside to the inside. On the one hand, it can blow the remaining water stains and impurities outwards. On the other hand, since the air flow enters from the outside, it can form a uniform air flow layer on the inner wall of the test tube, accelerating the evaporation and drying process of the moisture.

[0040] Among them: The above setting method can also prevent water from accumulating inside the test tube. Since the air flow enters from the outside, it can effectively carry away the moisture, preventing the influence of accumulated water on the drying effect. When the double - helix cleaning component is used in combination with the inclined detection tube, the fluid enters and exits obliquely. This design enables the spiral fluid and the spiral air flow to better conform to the inclined angle of the detection tube, forming a smoother flow path along the tube wall. The obliquely entering fluid can, with the dual action of gravity and the spiral force, more deeply scour the inner wall of the test tube, while the obliquely exiting fluid can more smoothly carry out the residual substances and moisture out of the test tube, avoiding the accumulation and back - flow of the fluid inside the test tube, and further improving the cleaning and drying efficiency.

[0041] Among them: Compared with the complex cleaning method of using a water pump for drainage, a hot air blower for drying, and a brush for auxiliary cleaning in the cited document, the present invention, through the ingeniously designed double - helix cleaning component, utilizes the synergistic effect of the water pump, the air pump, and the spiral bars to achieve efficient cleaning and drying functions, reducing the dependence on additional complex equipment such as brushes. This simplified design not only reduces the manufacturing cost of the equipment but also reduces the maintenance and servicing costs of the equipment. At the same time, due to the remarkable cleaning and drying effects of the present invention, it can effectively avoid the deviation of test results caused by incomplete cleaning, reducing the possibility of repeated testing, and further saving the testing cost and time cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Front - view three - dimensional schematic diagram of the main structure of the present invention;

[0043] Figure 2 Rear - view three - dimensional schematic diagram of the main structure of the present invention;

[0044] Figure 3 Partial three - dimensional schematic diagram of the composite discharge component of the present invention;

[0045] Figure 4 For the present invention Figure 2 Three - dimensional schematic diagram of the enlarged structure at position A in the present invention;

[0046] Figure 5 For the present invention Figure 2 Three - dimensional schematic diagram of the enlarged structure at position B in the present invention;

[0047] Figure 6 Cross - sectional three - dimensional schematic diagram of the composite discharge component of the present invention;

[0048] Figure 7 Cross - sectional three - dimensional schematic diagram of the double - helix cleaning component of the present invention;

[0049] Figure 8 Three - dimensional schematic diagram of the spiral interface of the present invention.

[0050] In the figure:

[0051] 11. Frame; 12. Detection unit; 13. Test tube rack; 14. Test tube for detection;

[0052] 2. Composite discharging assembly; 21. Micro motor; 22. Counterweight; 23. Limit shaft; 24. Contact plate; 25. Spring; 26. First connecting seat; 27. Second connecting seat; 28. Telescopic rod; 29. Synchronous belt; 210. Collection box;

[0053] 3. Double - helix cleaning assembly; 31. Mounting plate; 32. Spiral interface; 33. Outer spiral strip; 34. Inner spiral strip; 35. Water pump; 36. Air pump; 37. Connecting pipe. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0055] It should be noted that the detection unit 12 only provides the functions of adding color - developing agent and comparing colors for the test tube 14 for detection, and its working principle and specific structure are both prior arts. Therefore, due to the generality of the above - mentioned structure, the specific principle will not be described in detail hereinafter.

[0056] Example 1, please refer to as Figures 1 to 6 shown, a food heavy metal detector includes a frame 11, a detection unit 12 is installed on the frame 11, a test tube rack 13 is rotatably connected inside the frame 11, several test tubes 14 for detection are installed inside the test tube rack 13, a composite discharging assembly 2 is arranged inside the frame 11, the composite discharging assembly 2 includes two micro motors 21, the two micro motors 21 are symmetrically installed on the outer surface of the frame 11, a counterweight 22 is symmetrically fixedly connected to the output shaft of each micro motor 21, several springs 25 are installed on the inner wall of the frame 11, a contact plate 24 is installed at the top of the spring 25, several first connecting seats 26 are installed at the top of the contact plate 24, several second connecting seats 27 are installed at the bottom of the test tube rack 13, and a telescopic rod 28 is rotatably connected between each first connecting seat 26 and second connecting seat 27.

[0057] Please refer to as Figures 1 to 6 shown, the counterweight 22 is in the shape of a circular notch, a limit shaft 23 is fixedly connected to the bottom of the inner cavity of the frame 11, the contact plate 24 is slidably connected to the outer surface of the limit shaft 23, a synchronous belt 29 is drivingly connected between the output shaft of the micro motor 21 and the test tube 14 for detection, and a collection box 210 is installed at the bottom of the inner cavity of the frame 11.

[0058] It should be noted that a position sensor is installed on the inner wall of the rack 11. The position sensor is used to detect the position of the test tube 14. The diameter of the output shaft of the micro-motor 21 is larger than the diameter of the test tube rack 13.

[0059] Specifically, when the detection unit 12 finishes detecting the liquid food in the test tube 14, in order to perform the next batch of detections, it is necessary to completely drain the liquid in the test tube 14. At this time, the operator starts the micro-motor 21.

[0060] After the micro-motor 21 is started, its output shaft starts to rotate at a high speed. Since the output shaft of the micro-motor 21 and the test tube 14 are connected by a synchronous belt 29 for transmission, according to the principle of belt transmission, the rotation of the output shaft of the micro-motor 21 will be transmitted to the test tube rack 13 through the synchronous belt 29, thereby driving the test tube rack 13 to rotate. Also, because the diameter of the output shaft of the micro-motor 21 is larger than the diameter of the test tube rack 13, according to the relationship between the linear velocity and angular velocity of circular motion and the principle of transmission ratio, during the belt transmission process, when the larger-diameter driving wheel, the output shaft of the micro-motor 21, drives the smaller-diameter driven wheel, the test tube rack 13 to rotate, the rotational speed of the driven wheel will be relatively slow. Therefore, the test tube rack 13 will rotate at a relatively slow and stable speed.

[0061] At the same time, the rotation of the micro-motor 21 will also drive the counterweight 22 fixedly connected to it to rotate together. The counterweight 22 is designed in the shape of a circular notch. During its rotation, due to its special shape and mass distribution, there will be a periodic change in centrifugal force. When the counterweight 22 rotates to a specific position, it will collide with the contact plate 24.

[0062] When the counterweight 22 collides with the contact plate 24, the contact plate 24 will receive a downward pressure. Under the action of this pressure, the contact plate 24 will move downward against the elastic force of the spring 25. And when the counterweight 22 continues to rotate and disengages from the contact with the contact plate 24, the spring 25 will, due to its own elastic restoring force, push the contact plate 24 upward. At the same time, the contact plate 24 is slidably connected to the outer surface of the limit shaft 23, and the limit shaft 23 plays a role in restricting and guiding the movement of the contact plate 24, ensuring that the contact plate 24 can only vibrate up and down in the vertical direction.

[0063] In this way, under the continuous rotation of the counterweight 22, the contact plate 24 will continuously vibrate up and down under the action of the elastic force of the spring 25 and the restriction of the limit shaft 23. According to the principle of force transmission, the vibration force generated by the up and down vibration of the contact plate 24 will be transmitted to the test tube rack 13 through the connecting seat one 26, the telescopic rod 28, and the connecting seat two 27.

[0064] Since the test tube rack 13 is already in a slow rotation state driven by the micromotor 21, coupled with the vibration force transmitted by the resistance plate 24, the test tube rack 13 will vibrate while rotating. This combination of rotation and vibration has a significant effect on the discharge of liquid in the detection tube 14. During the rotation process, the liquid in the detection tube 14 is affected by the centrifugal force and will gather at the bottom of the detection tube 14; and the vibration can break the surface tension of the liquid, making it easier for the liquid to be discharged from the bottom of the detection tube 14.

[0065] In addition, the detection tube 14 is ultimately in an inclined state. Under the combined effects of the inclination and vibration force, the liquid in the detection tube 14 can flow downward along the tube wall more smoothly, and finally be discharged into the collection box 210 installed at the bottom of the inner cavity of the frame 11. During the entire drainage process, the position sensor installed on the inner wall of the frame 11 will monitor the position of the detection tube 14 in real time, so that the operator can accurately grasp the drainage situation and ensure the smooth progress of the drainage process.

[0066] Example 2, based on Example 1, please refer to Figure 1 , Figure 2 as well as Figure 7 and Figure 8 As shown, a double spiral cleaning assembly 3 is arranged inside the frame 11, and the double spiral cleaning assembly 3 includes a mounting plate 31 fixedly connected to the inside of the frame 11, and a plurality of spiral interfaces 32 are installed at the bottom of the mounting plate 31, and an outer spiral strip 33 is fixedly connected to the outer edge of the spiral interface 32, and an inner spiral strip 34 is fixedly connected to the inner edge of the spiral interface 32. A water pump 35 is installed on the outer surface of the frame 11, and an air pump 36 is installed on the outer surface of the frame 11 and on the side away from the water pump 35.

[0067] It should be noted that two groups of connecting pipes 37 are arranged outside the frame 11, one group of connecting pipes 37 is interconnected with the water pump 35 and the inner spiral strip 34, and the other group of connecting pipes 37 is interconnected with the air pump 36 and the outer spiral strip 33. The thread directions of the outer spiral strip 33 and the inner spiral strip 34 are opposite, and the thread shapes of the outer spiral strip 33 and the inner spiral strip 34 are also opposite.

[0068] Specifically, when the liquid in the detection tube 14 is drained, the detection tube 14 is in a tilted state. At this time, the operator starts the water pump 35 , and the water pump 35 starts to work to transport water to the inside of the spiral interface 32 through the connecting pipe 37 .

[0069] Since the inner edge of the spiral interface 32 is fixedly connected with an inner spiral strip 34, and the connecting pipe 37 is in communication with the inner spiral strip 34, when water flows into the spiral interface 32, it will flow along the thread shape of the inner spiral strip 34. The special thread structure of the inner spiral strip 34 causes the water flow to form a spiral fluid under its guidance. Specifically, the thread shape of the inner spiral strip 34 provides a spiral channel for the water flow. The water flow is constrained and guided by the spiral strip in this channel, thus forming a spiral flow pattern.

[0070] First, when the spiral fluid flows inside the detection tube 14, it can generate a uniform and continuous centrifugal force. This centrifugal force enables the water flow to cover the inner wall of the detection tube 14 more comprehensively, including some corners and fine parts that are difficult to reach by traditional straight water flows. For the stains that may remain on the inner wall of the detection tube 14, the spiral fluid can wash them from all directions, greatly improving the thoroughness of cleaning. Second, the flow mode of the spiral fluid makes the residence time of the water flow in the detection tube 14 relatively long. Compared with the straight water flow, it can contact the stains more fully, thus more effectively dissolving and carrying away the stains.

[0071] When the inside of the detection tube 14 is washed clean by the spiral fluid, the water pump 35 is turned off and the air pump 36 is started. After the air pump 36 works, air enters the spiral interface 32 through another set of connecting pipes 37 and forms a spiral gas under the action of the outer spiral strip 33. This is because the thread structure of the outer spiral strip 33 provides a similar spiral channel for the air flow. The air flow is guided and constrained in the channel, thus forming a spiral flow.

[0072] The spiral gas has many benefits. On the one hand, when the spiral gas flows inside the detection tube 14, it can further remove the tiny water stains and stain particles that may remain on the inner wall of the detection tube 14. The high-speed rotation and flow of the spiral gas can blow these remaining substances off the tube wall, playing a role in secondary cleaning. On the other hand, the flow of the spiral gas can accelerate the air circulation inside the detection tube 14, take away the moisture, thus achieving the effect of rapid drying. Rapid drying can prevent bacteria from growing or corrosion from occurring on the inner wall of the detection tube 14, and at the same time provides a dry environment for the next detection, ensuring the accuracy of the detection results.

[0073] It should be noted that since the outer spiral strip 33 is located at the outer edge of the spiral interface 32, after the spiral gas enters the detection tube 14 from the outer edge, it will blow the tube wall from the outside to the inside. This blowing method can gather the remaining stains and moisture towards the center of the detection tube 14, and then discharge them from the detection tube 14 under the drive of the air flow. At the same time, the spiral gas entering from the outer edge can form a uniform air flow layer on the inner wall of the detection tube 14, making the drying process more uniform and avoiding the situation of local overheating or overwetting.

[0074] It is also of great significance that the thread directions of the outer spiral strip 33 and the inner spiral strip 34 are opposite. When the spiral fluid and the spiral gas are formed, due to the opposite thread directions, their flow directions inside the detection tube 14 are also opposite. This opposite flow direction enables the spiral fluid and the spiral gas to clean and process the inner wall of the detection tube 14 in a cross - type manner. The spiral fluid flushes from the inside out, and the spiral gas blows from the outside in. The two cooperate with each other, can more comprehensively cover the inner wall of the detection tube 14, further improve the quality of cleaning and drying, and ensure that there are no cleaning dead corners.

[0075] During the entire cleaning process, the stains removed will fall into the collection box 210 along the inclined direction of the detection tube 14 under the action of gravity and air flow. In this way, through the coordinated work of the double - spiral cleaning assembly 3, the efficient cleaning and drying of the detection tube 14 are realized, providing a reliable guarantee for the subsequent detection work.

[0076] Example 3, method for using a food heavy - metal detector, includes the following steps:

[0077] Step 1: First, preheat the detector. The calibration wavelength depends on the type of heavy metal to be detected. Connect the power supply and turn on the switch. After the preheating is completed, take 5 ml of the heavy - metal standard solution, inject it into the cuvette, place it in the detection slot, and select the corresponding detection item and calibration wavelength according to the instrument prompt for calibration.

[0078] Step 2: Stir the liquid sample evenly, add nitric acid for digestion. The digestion temperature is 180 - 220 °C and the time is 30 - 60 minutes. After digestion, cool it and make the volume constant to 50 ml to obtain the sample solution to be measured.

[0079] Step 3: The dosage of the color - developing agent is 1 - 5 ml, the color - developing reaction time is 5 - 30 minutes, and the color - developing reaction temperature is 25 °C. Take 5 ml of the sample solution to be measured, inject it into the cuvette, add the color - developing agent and shake well.

[0080] Step 4: The detection wavelength is the same as the calibration wavelength. Place the developed cuvette in the detection slot, select the corresponding item and wavelength to start the detection. The instrument measures the absorbance and displays the result according to the calibration curve for the acid content. Record and judge whether it exceeds the standard. If it is abnormal, retest or check and calibrate the instrument.

[0081] Step 5: Take out the cuvette, rinse it, dry it, turn off the power supply of the instrument, unplug the plug, clean the instrument and the working area, and properly store the instrument and reagents.

[0082] In step 1, the preheating time is thirty minutes.

[0083] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0084] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A food heavy metal detector, comprising a frame (11), a detection unit (12) being mounted on the frame (11), a test tube rack (13) being rotatably connected inside the frame (11), a plurality of detection tubes (14) being mounted inside the test tube rack (13), characterized in that: A composite discharge assembly (2) is arranged inside the frame (11), and the composite discharge assembly (2) comprises two micromotors (21), the two micromotors (21) are symmetrically mounted on the outer surface of the frame (11), the output shaft of each micromotors (21) is symmetrically fixedly connected with a counterweight (22), a plurality of springs (25) are mounted on the inner wall of the frame (11), a resistance plate (24) is mounted on the top of the springs (25), a plurality of connecting seats (26) are mounted on the top of the resistance plates (24), a plurality of connecting seats (27) are mounted on the bottom of the test tube rack (13), and a telescopic rod (28) is rotatably connected between each connecting seat (26) and each connecting seat (27).

2. A food heavy metal detector according to claim 1, characterized in that: The counterweight block (22) is in the shape of a circular notch.

3. A food heavy metal detector according to claim 1, characterized in that: The bottom of the inner cavity of the frame (11) is fixedly connected to a limit shaft (23), and the abutment plate (24) is slidably connected to the outer surface of the limit shaft (23).

4. A food heavy metal detector according to claim 1, characterized in that: A synchronous belt (29) is connected in transmission between the output shaft of the micromotor (21) and the detection tube (14).

5. A food heavy metal detector according to claim 1, characterized in that: A collection box (210) is installed at the bottom of the inner cavity of the frame (11).

6. A food heavy metal detector according to claim 1, characterized in that: A double spiral cleaning assembly (3) is arranged inside the frame (11), and the double spiral cleaning assembly (3) comprises a mounting plate (31) fixedly connected to the inside of the frame (11); a plurality of spiral interfaces (32) are mounted on the bottom of the mounting plate (31); an outer spiral strip (33) is fixedly connected to the outer edge of the spiral interface (32); an inner spiral strip (34) is fixedly connected to the inner edge of the spiral interface (32); a water pump (35) is mounted on the outer surface of the frame (11); and an air pump (36) is mounted on the outer surface of the frame (11) and on a side away from the water pump (35).

7. A food heavy metal detector according to claim 6, characterized in that: Two groups of connecting pipes (37) are arranged outside the frame (11), wherein one group of the connecting pipes (37) is interconnected with the water pump (35) and the inner spiral strip (34), and the other group of the connecting pipes (37) is interconnected with the air pump (36) and the outer spiral strip (33).

8. A food heavy metal detector according to claim 7, characterized in that: The thread directions of the outer spiral strip (33) and the inner spiral strip (34) are opposite, and the thread shapes of the outer spiral strip (33) and the inner spiral strip (34) are also opposite.

9. A method for using a food heavy metal detector, applied to a food heavy metal detector as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Preheat the detector first. The calibration wavelength depends on the type of heavy metal to be detected. Turn on the power and turn on the switch. After preheating is completed, take 5ml of heavy metal standard solution and inject it into the cuvette and put it into the detection tank. Select the corresponding detection item and calibration wavelength according to the instrument prompts; Step 2: Stir the liquid sample evenly, add nitric acid to digest it, the digestion temperature is 180-220℃, the time is 30-60 minutes, and after digestion, cool and dilute to 50ml to obtain the sample solution to be tested; Step 3: The amount of color developer is 1-5 ml, the color development time is 5-30 minutes, the color development temperature is 25°C, take 5 ml of the sample solution to be tested and inject it into the colorimetric dish, add the color developer and shake well; Step 4: The detection wavelength is the same as the calibration wavelength. Put the colorimetric dish into the detection tank after color development. Select the corresponding item and wavelength to start the detection. The instrument measures the absorbance and displays the result according to the acid content of the calibration curve. Record and judge whether it exceeds the standard. If abnormal, re-measure or check the calibration instrument; Step 5: Take out the cuvette, rinse and dry it, turn off the instrument power and unplug it, clean the instrument and work area, and properly store the instrument reagents.

10. The method for using the food heavy metal detector according to claim 9, characterized in that: In the step 1, the preheating time is thirty minutes.

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