Layered sampling equipment for food detection

Abstract

The invention belongs to the technical field of food biological detection, and particularly relates to stratified sampling equipment for food detection, which comprises a containing barrel, a bracket is fixedly arranged at the top of the containing barrel, a vertical stabilizing sleeve is fixedly arranged in the middle of the bracket, and a lifting pipe is vertically and slidably arranged in the vertical stabilizing sleeve. A lifting pipe is fixedly installed on the top of the vertical stabilizing sleeve, a sampling head is fixedly installed at the lower end of the lifting pipe, a suction mechanism is arranged in the lifting pipe, a PLC is fixedly installed on the outer wall of the lifting pipe, the air cylinder is fixedly arranged on one side of the top of the vertical stabilizing sleeve, and the moving end of the air cylinder is fixedly connected with the pipe wall of the lifting pipe. According to the invention, each layer of milk can be automatically detected, liquid in each layer can be accurately sampled, the phenomenon of sampling pollution of the liquid in each layer is avoided, the accuracy and efficiency of detection of microbial bacteria in milk are improved, and subsequent production and processing of milk are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of food biological detection, and in particular relates to a layered sampling device for food detection. Background Art

[0002] At present, fluid foods, such as milk, may be contaminated by microorganisms and bacteria. For example, milk may contain Staphylococcus aureus, Salmonella, Listeria, etc. In order to study the growth, metabolism and other activities of bacteria in different layers of milk (such as fat layer, aqueous layer or sediment layer), for example, yogurt, the growth of certain bacteria in various layers of yogurt may affect the acidity, texture and flavor of yogurt. Studying the growth of bacteria in each layer is helpful to optimize the fermentation process parameters. Before the study, it is necessary to sample the milk. For example, the publication number is: CN113933109A, which discloses a food detection sampling device.

[0003] When sampling existing milk, due to the different amounts of milk, under the same static conditions (such as temperature, container shape, etc.), the thickness of different layers is also different. When using conventional sampling equipment to sample different layers of milk, the sampling head of the sampling equipment cannot accurately control the insertion depth (often sampling the same layer twice or failing to sample some layers), and thus the fat layer, water phase layer and sedimentation layer of the milk cannot be accurately sampled, resulting in reduced parameter accuracy for subsequent research, and repeated sampling and testing may be required, resulting in reduced efficiency of research and testing.

[0004] Therefore, a stratified sampling device for food testing is proposed. Summary of the invention

[0005] The object of the present invention is to provide a stratified sampling device for food testing in view of the above problems.

[0006] To achieve the above object, the present invention adopts the following technical scheme: a stratified sampling device for food testing, comprising a container, a bracket is fixedly provided on the top of the container, a vertical stabilizing sleeve is fixedly provided in the middle of the bracket, a lifting tube is vertically slidably provided inside the vertical stabilizing sleeve, a sampling head is fixedly installed at the lower end of the lifting tube, a suction mechanism is provided inside the lifting tube, a PLC controller is fixedly installed on the outer wall of the lifting tube, and further comprising: A cylinder is fixedly arranged on one side of the top of the vertical stabilizing sleeve, and the movable end of the cylinder is fixedly connected to the wall of the lifting tube; A pressure detection mechanism is arranged on the side wall of the sampling head; A fat layer sampling tube is arranged inside the lifting tube, and a fat layer suction tube and a fat layer solenoid valve are provided at the top and bottom of the fat layer sampling tube, a water layer sampling tube is fixedly provided on one side of the fat layer sampling tube, and a water layer suction tube and a water layer solenoid valve are provided at the top and bottom of the water layer sampling tube, a sedimentation layer sampling tube is fixedly provided on one side of the water layer sampling tube, and a sedimentation layer suction tube and a sedimentation layer solenoid valve are provided at the top and bottom of the sedimentation layer sampling tube, and a liquid level trigger mechanism is provided inside the fat layer sampling tube, inside the water layer sampling tube and inside the sedimentation layer sampling tube; A layered sampling trigger mechanism, wherein a trigger box is fixedly disposed on the side wall of the vertical stabilizing sleeve, and the layered sampling trigger mechanism is disposed inside the trigger box; The suction mechanism, the cylinder, the pressure detection mechanism, the fat layer electromagnetic valve, the water phase layer electromagnetic valve, the sediment layer electromagnetic valve, the liquid level trigger mechanism and the stratified sampling trigger mechanism are all connected with the PLC controller by electrical signals.

[0007] In the above-mentioned stratified sampling equipment for food testing, the suction mechanism includes a motor fixedly installed on the upper side of the lifting tube, a screw rod is fixedly provided at the output end of the motor, a threaded barrel is threaded at the lower end of the screw rod, a piston is fixedly provided at the lower end of the threaded barrel, and limit blocks slidably connected to the inner wall of the lifting tube are fixedly provided on both sides of the threaded barrel.

[0008] In the above-mentioned stratified sampling equipment for food testing, the pressure detection mechanism includes a pressure silicon sheet, a protective tube is fixedly provided on the side wall of the sampling head, the opening of the protective tube is set upward, and the pressure silicon sheet is fixedly installed on the inner wall of the opening of the protective tube.

[0009] In the above-mentioned stratified sampling equipment for food inspection, the stratified sampling trigger mechanism includes an electromagnetic telescopic rod fixedly arranged on the inner wall of a trigger box, a switch touch head is fixedly arranged on the movable end of the electromagnetic telescopic rod, a fat layer switch, an aqueous layer switch and a sedimentation layer switch are fixedly arranged on the bottom inner wall of the trigger box from right to left in sequence, and a resistance elimination mechanism is arranged on the top of the trigger box.

[0010] In the above-mentioned stratified sampling equipment for food testing, the resistance elimination mechanism includes a resistance elimination conductive ring and a resistance elimination resistor rod, the resistance elimination resistor rod is fixedly arranged on the top inner wall of the trigger box, the resistance elimination conductive ring is slidably arranged on the rod wall of the resistance elimination resistor rod, and the bottom of the resistance elimination conductive ring is fixedly connected to the top of the switch contact head.

[0011] In the above-mentioned stratified sampling equipment for food testing, the liquid level trigger mechanism includes a floating plate and a liquid level trigger switch, and the floating plate is provided on the inner lower side of the fat layer sampling tube, the inner lower side of the water layer sampling tube and the inner lower side of the sediment layer sampling tube, and the liquid level trigger switch is fixedly installed on the inner upper side of the fat layer sampling tube, the inner upper side of the water layer sampling tube and the inner upper side of the sediment layer sampling tube.

[0012] In the above-mentioned stratified sampling equipment for food testing, a waste liquid sampling tube is fixedly provided on one side of the sedimentation layer sampling tube, and waste liquid suction tubes and waste liquid solenoid valves are provided at the top and bottom of the waste liquid tube, and the waste liquid solenoid valve is electrically connected to the PLC controller.

[0013] In the above-mentioned stratified sampling equipment for food testing, drain pipes and observation windows are provided at positions corresponding to the positions of the fat layer sampling tube, the water layer sampling tube, the sedimentation layer sampling tube and the waste liquid sampling tube on the tube wall of the lifting tube, and a manual ball valve is provided on the tube wall of the lifting tube, and a transparent protective cover is provided on the tube wall of the lifting tube to block the drain pipe and the observation window.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the set pressure detection mechanism, the cylinder can drive the lifting tube to move downward when it retracts, so that the sampling head at the lower end of the lifting tube and the pressure detection mechanism are inserted into the milk in the filling tube together. The pressure detection mechanism can automatically detect the stratified milk, and then send the detection signal to the PLC controller. The PLC controller controls the suction mechanism in turn to suck the liquid of each layer of the milk into the fat layer sampling tube, the water layer sampling tube and the sedimentation layer sampling tube, so as to complete the accurate sampling of the cow stratification, improve the accuracy of microbial bacteria detection in milk, and improve the detection efficiency at the same time.

[0015] 2. Through the set stratified sampling trigger mechanism, the pressure detection mechanism's own resistance changes during the stratified detection of milk, and then the change of current in the loop is fed back to the stratified sampling trigger mechanism, so that the stratified sampling trigger mechanism can be triggered in each layer and feed back an electrical signal to the PLC controller, thereby triggering automatic sampling of the liquid in each layer.

[0016] 3. Through the set liquid level trigger mechanism and waste liquid sampling tube, during the process of sucking liquid from the inside of the fat layer sampling tube, the water layer sampling tube and the sediment layer sampling tube, the liquid level trigger mechanism can be triggered according to the maximum amount of liquid sucked, and then the liquid level trigger mechanism will feedback downward to the PLC controller and open the pipeline of the waste liquid sampling tube, and suck out the upper layer of liquid remaining at the lower end of the lifting tube and the inside of the sampling head to avoid sampling contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a stereoscopic diagram of a layered sampling device for food testing provided by the present invention; Figure 2 It is a schematic diagram of the planar structure of a stratified sampling device for food testing provided by the present invention; Figure 3 It is a schematic diagram of the structure inside the lifting tube of a stratified sampling device for food testing provided by the present invention; Figure 4 It is a schematic diagram of the structure of a fat layer sampling tube, a water layer sampling tube, a sediment layer sampling tube and a waste liquid sampling tube of a stratified sampling device for food testing provided by the present invention; Figure 5 It is a structural schematic diagram of a part of the lower end of a lifting tube of a stratified sampling device for food testing provided by the present invention; Figure 6 The present invention is a schematic diagram of the structure inside a trigger box of a stratified sampling device for food testing.

[0018] In the figure: 1 containing barrel, 2 bracket, 3 vertical stabilizing sleeve, 4 lifting tube, 5 sampling head, 6 suction mechanism, 61 motor, 62 screw rod, 63 threaded tube, 64 piston, 7 PLC controller, 8 cylinder, 9 pressure detection mechanism, 91 pressure silicon sheet, 92 protective tube, 10 fat layer sampling tube, 11 water phase layer sampling tube, 12 sedimentation layer sampling tube, 13 fat layer suction tube, 14 fat layer solenoid valve, 15 water phase layer suction tube, 16 water phase layer solenoid valve, 17 sedimentation layer suction tube, 18 sedimentation layer Solenoid valve, 19 liquid level trigger mechanism, 191 floating plate, 192 liquid level trigger switch, 20 layered sampling trigger mechanism, 201 electromagnetic telescopic rod, 202 switch touch head, 203 fat layer switch, 204 water layer switch, 205 sedimentation layer switch, 21 trigger box, 22 resistance elimination mechanism, 221 resistance elimination conductive ring, 222 resistance elimination resistor rod, 23 waste liquid sampling tube, 24 waste liquid suction tube, 25 waste liquid solenoid valve, 26 drain pipe, 27 observation window, 28 manual ball valve, 29 transparent protective cover. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0020] like Figure 1-Figure 6As shown, a stratified sampling device for food testing comprises a container 1, a bracket 2 is fixedly provided on the top of the container 1, a vertical stabilizing sleeve 3 is fixedly provided in the middle of the bracket 2, a lifting tube 4 is vertically slidably provided inside the vertical stabilizing sleeve 3, a sampling head 5 is fixedly installed at the lower end of the lifting tube 4, a suction mechanism 6 is provided inside the lifting tube 4, the suction mechanism 6 comprises a motor 61 fixedly installed on the upper side of the lifting tube 4, a screw rod 62 is fixedly provided at the output end of the motor 61, a threaded barrel 63 is threadedly provided at the lower end of the screw rod 62, a piston 64 is fixedly provided at the lower end of the threaded barrel 63, and both sides of the threaded barrel 63 are fixedly provided with a screw rod 62 fixedly provided with a screw rod 63. The inner wall of the lifting tube 4 is slidably connected to a limit block, and the motor 61 drives the screw rod 62 to rotate. The screw rod 62 drives the threaded cylinder 63 and the piston 64 to move upward. During the upward movement, the piston 64 causes the interior of the lifting tube 4 and the sampling head 5 to be in a negative pressure state. The outer wall of the lifting tube 4 is fixedly installed with a PLC controller 7, and also includes: a cylinder 8, which is fixedly arranged on one side of the top of the vertical stabilizing sleeve 3. The moving end of the cylinder 8 is fixedly connected to the tube wall of the lifting tube 4. When the cylinder 8 is in a telescopic action, it can make the lifting tube 4 move up and down inside the filling barrel 1, so that the sampling head 5 can be inserted into the milk or removed from the milk.

[0021] The pressure detection mechanism 9 is arranged on the side wall of the sampling head 5. The pressure detection mechanism 9 includes a pressure silicon sheet 91. A protective tube 92 is fixedly provided on the side wall of the sampling head 5. The opening of the protective tube 92 is arranged upward. The pressure silicon sheet 91 is fixedly installed on the inner wall of the opening of the protective tube 92. When the sampling head 5 moves downward with the lifting tube 4, the protective tube 92 moves in the milk. At this time, the protective tube 92 can avoid the impact force generated by the direct contact between the bottom of the pressure silicon sheet 91 and the milk, thereby improving the accuracy of the pressure detection of the pressure silicon sheet 91.

[0022] The fat layer sampling tube 10 is arranged inside the lifting tube 4, and the top and bottom of the fat layer sampling tube 10 are both provided with a fat layer suction tube 13 and a fat layer electromagnetic valve 14, a water layer sampling tube 11 is fixedly arranged on one side of the fat layer sampling tube 10, and the top and bottom of the water layer sampling tube 11 are both provided with a water layer suction tube 15 and a water layer electromagnetic valve 16, a sedimentation layer sampling tube 12 is fixedly arranged on one side of the water layer sampling tube 11, and the top and bottom of the sedimentation layer sampling tube 12 are both provided with a sedimentation layer suction tube 17 and a sedimentation layer electromagnetic valve 18, a waste liquid sampling tube 23 is fixedly arranged on one side of the sedimentation layer sampling tube 12, and the top and bottom of the waste liquid tube are both provided with The waste liquid suction pipe 24 and the waste liquid solenoid valve 25 are electrically connected to the PLC controller 7. A drain pipe 26 and an observation window 27 are provided at the positions of the tube wall of the lifting tube 4 corresponding to the positions of the fat layer sampling tube 10, the water layer sampling tube 11, the sedimentation layer sampling tube 12 and the waste liquid sampling tube 23, and a manual ball valve 28 is provided on the tube wall of the drain pipe 26. The tube wall of the lifting tube 4 is provided with a transparent protective cover 29 that blocks the drain pipe 26 and the observation window 27. The color and state of the sampled liquid can be preliminarily observed through the observation window 27. When the sampled liquid needs to be discharged, the manual ball valve 28 is opened to allow the liquid to be discharged to the outside through the drain pipe 26.

[0023] The inside of the fat layer sampling tube 10, the inside of the water layer sampling tube 11 and the inside of the sediment layer sampling tube 12 are all provided with a liquid level trigger mechanism 19, and the liquid level trigger mechanism 19 includes a float plate 191 and a liquid level trigger switch 192. The inner lower side of the fat layer sampling tube 10, the inner lower side of the water layer sampling tube 11 and the inner lower side of the sediment layer sampling tube 12 are all provided with a float plate 191, and the inner upper side of the fat layer sampling tube 10, the inner upper side of the water layer sampling tube 11 and the inner upper side of the sediment layer sampling tube 12 are all fixedly installed with the liquid level trigger switch 192. Due to the buoyancy of the liquid, the float plate 191 moves upward, so that the float plate 191 contacts the liquid level trigger switch 192, and at this time the liquid level trigger switch 192 will feedback an electrical signal to the PLC controller 7.

[0024] The stratified sampling trigger mechanism 20 has a trigger box 21 fixedly disposed on the side wall of the vertical stabilizing sleeve 3. The stratified sampling trigger mechanism 20 is disposed inside the trigger box 21. The stratified sampling trigger mechanism 20 includes an electromagnetic telescopic rod 201 fixedly disposed on the inner wall of the trigger box 21. The movable end of the electromagnetic telescopic rod 201 is fixedly disposed with a switch contact head 202. A fat layer switch 203, an aqueous layer switch 204 and a sediment layer switch 205 are fixedly disposed on the bottom inner wall of the trigger box 21 from right to left in sequence. A resistance elimination mechanism 22 is disposed on the top of the trigger box 21. The resistance elimination mechanism 22 includes a resistance elimination conductive ring 221 and a resistance elimination resistor rod 222. The resistance elimination resistor rod 222 is fixedly disposed on the top inner wall of the trigger box 21. The conductive ring 221 is slidably set on the rod wall of the resistance rod 222, and the bottom of the resistance conductive ring 221 is fixedly connected to the top of the switch contact head 202. During the movement of the electromagnetic telescopic rod 201, the switch contact head 202 will contact the fat layer switch 203, the water layer switch 204 and the sedimentation layer switch 205 in turn and give feedback signals to the PLC controller 7. During the retraction action of the electromagnetic telescopic rod 201, the resistance conductive ring 221 is driven to move on the resistance rod 222, so that the resistance value of the resistance rod 222 connected to the circuit becomes smaller, thereby being able to offset the resistance value of the pressure silicon sheet 91 increased due to the depth, and avoiding the depth from interfering with the pressure detection of the pressure silicon sheet 91.

[0025] The suction mechanism 6, the cylinder 8, the pressure detection mechanism 9, the fat layer solenoid valve 14, the water layer solenoid valve 16, the sedimentation layer solenoid valve 18, the liquid level trigger mechanism 19, the stratified sampling trigger mechanism 20, and the waste liquid solenoid valve 25 are all connected to the PLC controller 7 via electrical signals.

[0026] The operating principle of the present invention is as follows: first, pour the milk into the container 1 and let it stand for 50 minutes. Under normal circumstances, the milk will appear in two layers in the container 1, the upper layer is a fat layer with a density range of 0.9-0.93, and the lower layer is a water layer with a density range of 1.02-1.04. If the milk is spoiled or left for a long time, three layers will appear, namely, an upper fat layer (density 0.9-0.93), a middle water layer (density 1.02-1.04) and a lower sedimentation layer (density 1.1-1.5). The following is an explanation of the three layers.

[0027] Through manual operation of the PLC controller 7, the cylinder 8 is controlled to retract slowly, driving the lifting tube 4 to move slowly and steadily downward in the vertical stabilizing sleeve 3, so that the sampling head 5 and the pressure silicon sheet 91 at the lower end of the lifting tube 4 are slowly inserted into the milk (because the layers will flow during the insertion process, in order to avoid mutual interference, after the sampling head 5 is inserted into each layer, it is necessary to stop for 2-3 minutes to wait for each layer to restore its initial state). Because the density of each layer of milk is different, the pressure value of the pressure silicon sheet 91 in each layer is also different, and there is a corresponding pressure value range with the density value range of each layer. Assuming that the pressure of the fat layer is P1, the water phase layer is P2, and the sedimentation layer is P3 (P1>P2>P3), the pressure of the pressure silicon sheet 91 in each layer is p1, p2, p3 (p1>p2>p3); when the pressure silicon sheet 91 passes through the fat layer, the water phase layer and the sedimentation layer in turn, due to the gradual increase in pressure, the deformation degree of the pressure silicon sheet 91 also gradually increases, and its resistance value increases accordingly, causing the current value of the circuit connected to it to gradually decrease. In this way, the current of the electromagnetic telescopic rod 201 connected to the circuit becomes smaller, the magnetic force weakens and retracts, driving the switch contact head 202 to move. In addition, the pressure on the pressure silicon sheet 91 is also affected by the depth of the milk. The greater the downward movement depth, the greater the pressure. At this time, the retraction of the electromagnetic telescopic rod 201 will drive the anti-blocking conductive ring 221 to move on the anti-blocking resistor rod 222, so that the resistance value of the anti-blocking resistor rod 222 connected to the circuit becomes smaller, thereby offsetting the interference of the depth on the pressure detection of the pressure silicon sheet 91.

[0028] When the pressure silicon sheet 91 enters the fat layer, the electromagnetic telescopic rod 201 drives the switch contact head 202 to squeeze the fat layer switch 203, and the fat layer switch 203 sends an electrical signal to the PLC controller 7. The PLC controller 7 controls the fat layer solenoid valve 14 to open, the water phase layer solenoid valve 16 and the sedimentation layer solenoid valve 18 to close, and stops the cylinder 8 from working, so that the fat layer sampling tube 10 is opened. At the same time, the PLC controller 7 controls the motor 61 to operate, and the motor 61 drives the screw rod 62 to rotate. The screw rod 62 drives the threaded cylinder 63 and the piston 64 to move upward, so that negative pressure is formed inside the fat layer sampling tube 10 and the sampling head 5, and the fat layer liquid is sucked into the fat layer sampling tube 10. When the liquid in the fat layer sampling tube 10 increases to a certain amount, the buoyancy of the liquid causes the float 191 to move upward until it contacts the liquid level trigger switch 192. The liquid level trigger switch 192 feeds back an electrical signal to the PLC controller 7, and the PLC controller 7 stops the motor 61, closes the fat layer solenoid valve 14, and controls the cylinder 8 to continue working.

[0029] As the cylinder 8 retracts, it drives the pressure silicon sheet 91 into the water phase layer, and the electromagnetic telescopic rod 201 drives the switch contact head 202 to squeeze the water phase layer switch 204. The water phase layer switch 204 feeds back an electrical signal to the PLC controller 7. The PLC controller 7 controls the waste liquid solenoid valve 25 to open, stops the cylinder 8 from working, opens the waste liquid sampling tube 23, and then controls the motor 61 to work for 3 seconds. During this period, the piston 64 moves upward to completely absorb the fat layer liquid remaining between the lower end of the lifting tube 4 and the sampling head 5 into the waste liquid sampling tube 23 (this process will also absorb part of the water phase layer liquid). body), to avoid the upper liquid contaminating the lower liquid and improve the sampling accuracy. After the motor 61 has been working for 3 seconds, the PLC controller 7 automatically closes the waste liquid solenoid valve 25, and then controls the water phase layer solenoid valve 16 to open and the water phase layer sampling tube 11 to open, and then controls the motor 61 to work, so that the piston 64 moves up to suck the water phase layer liquid into the water phase layer sampling tube 11. When the amount of liquid in the water phase layer sampling tube 11 reaches a certain level, the floating plate 191 and the liquid level trigger switch 192 stop pumping the water phase layer liquid, and then the PLC controller 7 controls the cylinder 8 to continue working.

[0030] When the cylinder 8 retracts and drives the pressure silicon sheet 91 to enter the sedimentation layer, the electromagnetic telescopic rod 201 drives the switch touch head 202 to squeeze the sedimentation layer switch 205. After the sedimentation layer switch 205 is triggered, the PLC controller 7 triggers the waste liquid solenoid valve 25 in turn to open the waste liquid sampling tube 23, and at the same time controls the motor 61 to work, so that the aqueous phase layer liquid between the lower end of the lifting tube 4 and the sampling head 5 is completely sucked into the waste liquid sampling tube 23, and then the PLC controller 7 controls the sedimentation layer solenoid valve 18 to open, and the sedimentation layer liquid is sampled. When the liquid in the sedimentation layer sampling tube 12 increases to a certain amount, the suction of the sedimentation layer liquid is stopped through the action of the floating plate 191 and the liquid level trigger switch 192.

[0031] After completing the liquid sampling of the fat layer, water phase layer and sediment layer, the PLC controller 7 automatically controls the cylinder 8 to extend, so that the lifting tube 4 moves upward, and its lower end is separated from the milk surface. At this time, the sampled liquid condition can be preliminarily judged manually through the transparent protective cover 29 and the observation window 27; if the fat layer is contaminated with bacteria, white, green or black spots and hyphae may appear; if the water phase layer is contaminated with bacteria, there may be fine granular substances or flocs, and the transparency of the liquid is reduced; if the sediment layer is contaminated with bacteria, the sediment particles become larger or appear in a special color (such as reddish brown). After the preliminary judgment, open the transparent protective cover 29, and then open the manual ball valve 28 on the fat layer sampling tube 10, the water phase layer sampling tube 11, and the sediment layer sampling tube 12 to discharge the layered sampled liquid for subsequent culture and detection operations.

[0032] The above sampling process is mainly to sample the three layers of milk. If the milk has two layers, the pressure silicon sheet 91 can also detect the fat layer and the water layer of the milk accordingly, and can also accurately complete the sampling operation.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A stratified sampling device for food testing, comprising a container (1), a bracket (2) is fixedly provided on the top of the container (1), a vertical stabilizing sleeve (3) is fixedly provided in the middle of the bracket (2), a lifting tube (4) is vertically slidably provided inside the vertical stabilizing sleeve (3), a sampling head (5) is fixedly installed at the lower end of the lifting tube (4), a suction mechanism (6) is provided inside the lifting tube (4), and a PLC controller (7) is fixedly installed on the outer wall of the lifting tube (4), characterized in that: Also includes: A cylinder (8) is fixedly arranged on one side of the top of the vertical stabilizing sleeve (3), and a movable end of the cylinder (8) is fixedly connected to the wall of the lifting tube (4); A pressure detection mechanism (9) is arranged on a side wall of the sampling head (5); A fat layer sampling tube (10) is arranged inside the lifting tube (4), and a fat layer suction tube (13) and a fat layer electromagnetic valve (14) are provided at the top and bottom of the fat layer sampling tube (10); a water layer sampling tube (11) is fixedly provided on one side of the fat layer sampling tube (10), and a water layer suction tube (15) and a water layer electromagnetic valve (16) are provided at the top and bottom of the water layer sampling tube (11); a sedimentation layer sampling tube (12) is fixedly provided on one side of the water layer sampling tube (11), and a sedimentation layer suction tube (17) and a sedimentation layer electromagnetic valve (18) are provided at the top and bottom of the sedimentation layer sampling tube (12); and a liquid level trigger mechanism (19) is provided inside the fat layer sampling tube (10), inside the water layer sampling tube (11), and inside the sedimentation layer sampling tube (12); A layered sampling trigger mechanism (20), wherein a trigger box (21) is fixedly provided on the side wall of the vertical stabilizing sleeve (3), and the layered sampling trigger mechanism (20) is arranged inside the trigger box (21); The suction mechanism (6), the cylinder (8), the pressure detection mechanism (9), the fat layer solenoid valve (14), the water layer solenoid valve (16), the sediment layer solenoid valve (18), the liquid level trigger mechanism (19) and the layered sampling trigger mechanism (20) are all connected to the PLC controller (7) via electrical signals.

2. A stratified sampling device for food testing according to claim 1, characterized in that: The suction mechanism (6) comprises a motor (61) fixedly mounted on the upper side of the interior of the lifting tube (4); a screw rod (62) is fixedly mounted on the output end of the motor (61); a threaded barrel (63) is threadedly mounted on the lower end of the screw rod (62); a piston (64) is fixedly mounted on the lower end of the threaded barrel (63); and limit blocks slidably connected to the inner wall of the lifting tube (4) are fixedly mounted on both sides of the threaded barrel (63).

3. A stratified sampling device for food testing according to claim 1, characterized in that: The pressure detection mechanism (9) comprises a pressure silicon sheet (91), a protective tube (92) is fixedly provided on the side wall of the sampling head (5), the opening of the protective tube (92) is arranged upward, and the pressure silicon sheet (91) is fixedly mounted on the inner wall of the opening of the protective tube (92).

4. A stratified sampling device for food testing according to claim 1, characterized in that: The stratified sampling trigger mechanism (20) comprises an electromagnetic telescopic rod (201) fixedly arranged on the inner wall of a trigger box (21); a switch contact head (202) is fixedly arranged at the movable end of the electromagnetic telescopic rod (201); a fat layer switch (203), a water phase layer switch (204) and a sediment layer switch (205) are fixedly arranged on the bottom inner wall of the trigger box (21) in sequence from right to left; and a resistance elimination mechanism (22) is arranged on the top of the trigger box (21).

5. A stratified sampling device for food testing according to claim 4, characterized in that: The resistance elimination mechanism (22) comprises a resistance elimination conductive ring (221) and a resistance elimination resistor rod (222); the resistance elimination resistor rod (222) is fixedly arranged on the top inner wall of the trigger box (21); the resistance elimination conductive ring (221) is slidably arranged on the rod wall of the resistance elimination resistor rod (222); and the bottom of the resistance elimination conductive ring (221) is fixedly connected to the top of the switch contact head (202).

6. A stratified sampling device for food testing according to claim 1, characterized in that: The liquid level trigger mechanism (19) comprises a floating plate (191) and a liquid level trigger switch (192); the floating plate (191) is provided on the inner lower side of the fat layer sampling tube (10), the inner lower side of the water phase layer sampling tube (11), and the inner lower side of the sediment layer sampling tube (12); and the liquid level trigger switch (192) is fixedly mounted on the inner upper side of the fat layer sampling tube (10), the inner upper side of the water phase layer sampling tube (11), and the inner upper side of the sediment layer sampling tube (12).

7. A stratified sampling device for food testing according to claim 1, characterized in that: A waste liquid sampling tube (23) is fixedly provided on one side of the sedimentation layer sampling tube (12), and waste liquid suction tubes (24) and waste liquid solenoid valves (25) are provided at the top and bottom of the waste liquid tube, and the waste liquid solenoid valve (25) is electrically connected to the PLC controller (7).

8. A stratified sampling device for food testing according to claim 1, characterized in that: A drainage pipe (26) and an observation window (27) are provided at positions of the tube wall of the lifting tube (4) corresponding to the positions of the fat layer sampling tube (10), the water phase layer sampling tube (11), the sediment layer sampling tube (12) and the waste liquid sampling tube (23), and a manual ball valve (28) is provided on the tube wall of the drainage pipe (26). A transparent protective cover (29) is provided on the tube wall of the lifting tube (4) to block the drainage pipe (26) and the observation window (27).

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