Flexible pipeline, spiral quick freezer dry ice spraying device and control method thereof

Abstract

The present application relates to a kind of flexible pipeline, spiral quick freezer dry ice spraying device and its control method.A kind of spiral quick freezer dry ice spraying device, including liquid carbon dioxide storage device, flow regulating valve, flow meter, dry ice transport pipe, dry ice main road pipe, dry ice branch pipe, infrared temperature sensor;Liquid carbon dioxide storage device is connected with dry ice transport pipe, dry ice transport pipe is connected with dry ice main road pipe, dry ice main road pipe is installed around the middle part of the spiral ascending section of conveyor belt, dry ice main road pipe is equipped with dry ice branch pipe, the outlet of dry ice branch pipe sprays towards conveyor belt;Dry ice transport pipe is flexible pipeline.The dry ice spraying device proposed in the present application can be directly applied to the existing spiral quick freezer structure, and the modification cost is low, the dry ice spraying device can be closed for normal operation;When dry ice spraying device is opened, additional cooling capacity is provided by flow state dry ice to accelerate freezing, and the freezing quality of food is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a flexible pipeline, a spiral freezer dry ice spraying device and a control method thereof. BACKGROUND

[0002] The spiral freezer is a large-scale freezing equipment, mainly used for freezing fishery products. The fish body is sent into the spiral freezer through the conveyor belt, and the conveyor belt spirally rises inside the library body, while the air circulation in the library is driven by the fan to flow, and the temperature is lowered through the evaporator, usually the temperature in the library is-40℃ to-50℃. For most fish bodies, the temperature before entering the spiral freezer is at ambient temperature, and the temperature needs to reach-18℃ when sent out of the spiral freezer. Inside the library body, the fish body is mainly air-cooled in the form of forced convection, and the lower air temperature is used to accelerate cooling. The advantage of air cooling is low cost and no toxic side effects, but the air has poor heat conduction performance, and the convective heat transfer coefficient is not high, which requires a longer freezing time, resulting in low freezing efficiency. On the other hand, the freezing speed of air cooling is slow, so that the water in the cell freezes and grows for a long time, and the ice crystal grows to a certain size and pierces the cell, destroys the muscle protein structure, the water spreads to the outside of the cell, the nutrients are lost, and finally the quality of the food is reduced.

[0003] For most low-cost fish, considering the freezing cost and profit space, air cooling basically meets the requirements; but for high-end fish with high price, the freezing quality is required, and ordinary air cooling is difficult to meet the requirements. Therefore, an additional cooling source other than air cooling is needed to accelerate freezing, and the additional cooling source needs to be safe, non-toxic, large in cooling capacity, and low in cost. The use of dry ice for freezing fish food can meet all the above requirements. The temperature of dry ice during phase change can reach-78℃, and the cooling capacity released during phase change is large, which can significantly improve the freezing speed of the fish body; dry ice is lower in cost than liquid nitrogen, and is a high-performance-price ratio cooling source for food freezing.

[0004] There are three problems in the application of dry ice to fish body freezing. Firstly, the current spiral freezer in use adopts air cooling, and it is necessary to consider the modification of the existing device to embed the dry ice freezing device. In order to reduce the equipment modification cost as much as possible, the dry ice freezing device should be designed in combination with the structural characteristics of the existing spiral freezer. Secondly, the difficulty of using dry ice cooling is how to transport dry ice. The solid dry ice has poor fluidity and is difficult to transport through the pipeline. The dry ice must be treated to improve its transport performance, and the transport pipeline must be specially designed. Finally, the use of dry ice will increase the freezing cost, so it is necessary to reduce the amount of dry ice as much as possible. Considering that the cells of the fish body are in the maximum ice crystal generation zone when the temperature of the fish body is-1℃ to-5℃, the freezing speed can be significantly improved to improve the freezing quality of the fish body. Therefore, the fish body with a temperature of-1℃ to-5℃ should be frozen by dry ice, and the air cooling can be used in the remaining temperature range, so as to minimize the use of dry ice and compress the freezing cost. SUMMARY

[0005] The present application provides a spiral freezer dry ice spraying device, which is low-cost modified for the spiral freezer already put into use on the market, embeds the dry ice spraying device into the spiral freezer, improves the freezing speed and the freezing quality; uses the fluidized dry ice and the flexible pipeline to improve the transport performance of the dry ice; uses the infrared temperature sensor to monitor the fish body temperature in real time, automatically adjusts the action range of the dry ice spraying, sprays and freezes the maximum ice crystal generation zone with a temperature of-1℃ to-5℃, so that the dry ice supply and the freezing demand are matched. The cold energy utilization is maximized, and the dry ice freezing cost is reduced.

[0006] The technical scheme for solving the above problems of the present application is:

[0007] In the first aspect, the present application provides a flexible pipeline, which is characterized by:

[0008] The flexible pipeline comprises a flexible inner layer, a rigid outer layer and a thermal insulation layer arranged in sequence from inside to outside, and a soft filler layer is filled between the flexible inner layer and the rigid outer layer, and elastic supports are uniformly distributed in the soft filler layer.

[0009] Further, the thermal insulation layer is made of soft thermal insulation material, which is used to reduce the cold energy loss caused by heat exchange between the fluidized dry ice and the external environment during transportation.

[0010] Further, the rigid outer layer is made of rigid material, which can ensure the structural strength and pressure resistance of the pipeline.

[0011] Further, the soft filler layer is made of soft material with loose pores, which is used to enhance the heat insulation effect of the pipeline and also plays a buffering role to improve the pressure resistance of the pipeline.

[0012] Further, the flexible inner layer is a flexible material with strong elasticity, which can expand to increase the flow area when the pressure in the pipe increases, and can shrink to reduce the flow area when the pressure in the pipe decreases; the elastic support is a main component for controlling the flexibility of the pipeline, and is used for buffering the pressure received by the flexible inner layer.

[0013] Since the flow state dry ice is transported in the form of gaseous carbon dioxide wrapping dry ice powder, when the proportion of dry ice powder is relatively large, part of the dry ice may be deposited in the flexible pipeline to form a blockage, at this time, the flow area is reduced, the pressure drop of the pipeline is increased, the pressure on the inner wall of the pipeline is increased, the elastic support is compressed, and the flexible inner layer is expanded, so as to increase the flow area, thereby compensating for the blockage of the flow area caused by the deposition of dry ice. When the flow of the flow state dry ice increases, the pressure drop of the pipeline increases, the pressure on the inner wall of the pipeline increases, at this time, the elastic support is compressed, the flexible inner layer is expanded, the flow area is increased, and the pressure drop of the pipeline is reduced, thereby compensating for the increase in the pressure drop caused by the increase in the flow.

[0014] In a second aspect, the present application provides a dry ice spraying device for a spiral quick freezer, and the special feature is that:

[0015] The device comprises a liquid carbon dioxide storage device, a flow regulating valve, a flow meter, a dry ice conveying pipe, a dry ice main pipe, a dry ice branch pipe, and an infrared temperature sensor.

[0016] The liquid carbon dioxide storage device is connected with the dry ice conveying pipe, the flow regulating valve and the flow meter are arranged in the dry ice conveying pipe, the dry ice conveying pipe is connected with the dry ice main pipe, the dry ice main pipe is arranged around the middle part of the spiral ascending section of the conveying belt, the dry ice main pipe is provided with the dry ice branch pipe, and the outlet of the dry ice branch pipe is arranged to spray toward the conveying belt.

[0017] The dry ice conveying pipe is the flexible pipeline.

[0018] Further, the outer side of each dry ice branch pipe is provided with an infrared temperature sensor for measuring the temperature of the object to be frozen on the conveying belt.

[0019] Further, the dry ice branch pipe is provided with a switch valve, the dry ice branch pipe is provided with at least one dry ice spraying head, the bottom baffle is arranged on the lower side of the conveying belt to receive the dry ice powder, and the upper surface and the lower surface of the fish body are ensured to be cooled by the dry ice sublimation.

[0020] Further, the number of the dry ice spraying heads on the dry ice branch pipe is multiple, the multiple dry ice spraying heads are arranged at intervals on the dry ice branch pipe, and the interval of the spraying heads can ensure that the dry ice spraying completely covers the surface of the fish body.

[0021] In a third aspect, the present application provides a spiral quick freezer, and the special feature is that:

[0022] The spiral quick freezer body, the conveying belt, the fan, the evaporator, and the dry ice spraying device are included.

[0023] In a fourth aspect, the application provides a control method based on the dry ice spraying device of the spiral quick freezer, including a start process control method, an adjustment process control method, and a shutdown process control method.

[0024] The start process control method includes the following steps:

[0025] S101: After the spiral quick freezer is turned on, the library temperature starts to decrease, the real-time library temperature Tin is read, and it is determined whether the set value is reached. If not, repeat S101; if reached, enter S102.

[0026] S102: Read the temperature of all infrared temperature sensors arranged along the conveying belt, and determine whether the temperature value of the first infrared temperature sensor along the conveying belt running direction is equal to the library temperature Tin; if equal, repeat S102; if not equal, enter S103.

[0027] S103: Slowly open the flow regulating valve and enter S104.

[0028] S104: Read the temperature value of the infrared temperature sensor closest to the first fish body as the fish body temperature, and determine whether the fish body temperature reaches the upper limit set value T1 of the dry ice spraying section. Optionally, T1 is-1℃. If not reached, repeat S104; if reached, enter S105.

[0029] S105: Open the switch valve of the spraying branch closest to the current position of the first fish and enter S106.

[0030] S106: Open the switch valve of the next spraying branch every interval△t time.△t is equal to the time from the first fish entering a spraying range of a branch to leaving the spraying range of the branch. Read the temperature value of the infrared temperature sensor closest to the first fish body as the fish body temperature, and determine whether the first fish body temperature reaches the lower limit set value T2 of the dry ice spraying section. Optionally, T2 is-5℃. If not reached, repeat S106; if reached, enter S107.

[0031] S107: Stop opening the switch valve of the remaining spraying branches. The dry ice spraying device is started.

[0032] The adjustment process control method includes the following steps:

[0033] S201: When the fish size, fish species, fish density and other parameters change, causing the feed amount or working condition to change, the fish temperature at the first branch n being sprayed is read, and the size relationship between the fish temperature and the upper limit set value T1 of the dry ice spraying section is judged. If the fish temperature is greater than T1, the on-off valve of the first branch n being sprayed is closed, and S201 is repeated; if the fish temperature is less than T1, the on-off valve of the previous spraying branch n-1 is opened, and S201 is repeated; if the fish temperature is equal to T1, S202 is entered.

[0034] S202: The fish temperature at the last branch m being sprayed is read, and the size relationship between the fish temperature and the lower limit set value T2 of the dry ice spraying section is judged. If the fish temperature is greater than T2, the on-off valve of the next spraying branch m+1 is opened, and S202 is repeated; if the fish temperature is less than T2, the on-off valve of the last branch m being sprayed is closed, and S202 is repeated; if the fish temperature is equal to T2, S203 is entered.

[0035] S203: The number of branches being sprayed is counted, and S204 is entered.

[0036] S204: The opening degree of the flow regulating valve in the main line is adjusted, and whether the main line flow is equal to the total flow required by each branch is judged. If not, S204 is repeated; if yes, the dry ice spraying device is adjusted.

[0037] The closing process control method comprises the following steps:

[0038] S301: When the feed is stopped, the temperature value T of the infrared temperature sensor at the first branch n being sprayed is read, and whether T is equal to the library temperature Tin is judged. If not, S301 is repeated; if yes, S302 is entered.

[0039] S302: The on-off valve of the first branch n being sprayed is closed, and S303 is entered.

[0040] S303: Whether the spraying branches are all closed is judged. If not, S301 is repeated; if yes, S304 is entered.

[0041] S304: The flow regulating valve is slowly closed, and the dry ice spraying device is closed.

[0042] The advantages of the present application are:

[0043] 1. The dry ice spraying device can be directly applied to the existing spiral quick freezer structure, and the spiral quick freezer already put into use on the market can be low-cost transformed; when air cooling can meet the freezing demand, the dry ice spraying device is closed, and the spiral quick freezer can normally operate as a conventional spiral quick freezer; when air cooling cannot meet the freezing demand, the dry ice spraying device is opened, and the flow state dry ice provides additional cold quantity to accelerate freezing and improve the freezing quality of food.

[0044] 2. The dry ice spraying device adjusts the flow and pressure of the pipeline, so that the dry ice presents the form of carbon dioxide gas wrapping dry ice powder, that is, the form of flow state dry ice when the dry ice is transported in the pipeline, and the flowability of the dry ice is improved. The flexible pipeline can effectively avoid pipeline blockage caused by solid powder deposition, and can effectively cope with the change of dry ice flow, further improving the transportation capacity of the dry ice.

[0045] 3. The heat preservation structure adopted by the liquid carbon dioxide storage device and the flexible pipeline can effectively reduce the loss of dry ice cold quantity and improve the utilization rate of dry ice cold quantity.

[0046] 4. The dry ice spraying pipeline is arranged in the middle of the ascending section of the conveying belt, can completely cover the temperature interval of-1℃ to-5℃ of the fish body, so that the fish body passes through the maximum ice crystal generation zone faster. The infrared temperature sensor is arranged at intervals near the pipeline, which can monitor the fish body temperature at different positions on the conveying belt in real time, determine the position of the fish body at-1℃ to-5℃ on the conveying belt according to the temperature distribution of the fish body along the conveying belt, and then control the on-off valve of the corresponding dry ice branch pipe to ensure that the dry ice spraying is accurately applied to the temperature interval of-1℃ to-5℃. When the feed quantity or working condition parameter changes, the position of the fish body temperature in the interval of-1℃ to-5℃ on the conveying belt will also change accordingly, at this time, the infrared temperature sensor adjusts the position of the dry ice spraying action section in real time according to the monitored temperature, ensures that the dry ice spraying starts to act on-1℃ and stops acting on-5℃, so that the supply of dry ice quantity matches the required cold quantity, avoids waste of dry ice, and maximizes the cold quantity utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is the structure diagram of the spiral quick freezer provided by the present application;

[0048] Figure 2 is the structure diagram of the dry ice branch pipe;

[0049] Figure 3 is the structure diagram of the flexible pipeline;

[0050] Figure 4 is the start process control logic diagram of the dry ice spraying device;

[0051] Figure 5 is the adjustment process control logic diagram of the dry ice spraying device;

[0052] Figure 6 is a dry ice spraying device closing process control logic diagram.

[0053] Wherein: 1, spiral freezer main body, 2, conveyor belt, 3, fan, 4, evaporator, 5, liquid carbon dioxide storage device, 6, flow regulating valve, 7, flow meter, 8, dry ice transport pipe, 9, dry ice main pipe, 10, dry ice branch pipe, 11, infrared temperature sensor, 101, on-off valve, 102, dry ice spray head, 103, bottom baffle, 81, insulation layer, 82, rigid outer layer, 83, soft filler layer, 84, elastic support, 85, flexible inner layer. DETAILED DESCRIPTION

[0054] To make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application.

[0055] Reference Figure 3 A flexible pipeline for transporting dry ice in a flow state, comprising a flexible inner layer 85, a rigid outer layer 82 and an insulation layer 81 arranged in sequence from inside to outside, wherein the flexible inner layer 85 and the rigid outer layer 82 are filled with a soft filler layer 83, and the soft filler layer 83 is uniformly distributed with elastic supports 84.

[0056] The insulation layer 81 is a soft thermal insulation material, which is used to reduce the loss of cold energy caused by heat exchange between the dry ice in a flow state and the external environment during transportation.

[0057] The rigid outer layer 82 is tightly attached to the inside of the insulation layer 81, and the rigid outer layer 82 serves as a rigid shell of the flexible pipeline, which can ensure the structural strength and pressure resistance of the pipeline.

[0058] The soft filler layer 83 is tightly attached to the inside of the rigid outer layer 82, and the soft filler layer 83 is a loose and porous soft material, which is used to enhance the thermal insulation effect of the pipeline and also serves as a buffer to improve the pressure resistance of the pipeline.

[0059] The flexible inner layer 85 is tightly attached to the inside of the soft filler layer 83, and is a flexible material with strong elasticity. When the pressure in the pipe increases, the flexible inner layer 85 can expand to increase the flow area. When the pressure in the pipe decreases, the flexible inner layer 85 can shrink to reduce the flow area. The elastic support 84 is the main component for controlling the flexibility of the pipeline. The elastic support 84 is mainly a spring. In addition, the elastic support 84 can be made of any elastic metal material or non-metal material, such as an elastic gasket, an elastic column, etc., and is not limited to a common spiral spring in life.

[0060] Since the flow state dry ice is transported in the form of gas phase carbon dioxide wrapping dry ice powder, when the proportion of dry ice powder is relatively large, part of the dry ice may be deposited in the flexible pipeline to form a blockage. At this time, the flow area is reduced, the pressure drop of the pipeline is increased, and the pressure on the inner wall of the pipeline is increased. The increased pressure causes the elastic support 84 to compress and the flexible inner layer 85 to expand, thereby increasing the flow area and compensating for the blockage of the flow area caused by the deposition of dry ice.

[0061] When the flow of the flow state dry ice increases, the pressure drop of the pipeline increases, and the pressure on the inner wall of the pipeline increases. At this time, the elastic support 84 is compressed, the flexible inner layer 85 is expanded, the flow area is increased, and the pressure drop of the pipeline is reduced. Thus, the increase in pressure drop caused by the increase in flow is compensated.

[0062] Referring to Figure 1 and Figure 2 , a dry ice spraying device of a spiral quick freezer includes a liquid carbon dioxide storage device 5, a flow regulating valve 6, a flow meter 7, a dry ice conveying pipe 8, a dry ice main pipe 9, a dry ice branch pipe 10, and an infrared temperature sensor 11.

[0063] The liquid carbon dioxide storage device 5 is connected to the dry ice conveying pipe 8. The flow regulating valve 6 and the flow meter 7 are arranged in the dry ice conveying pipe 8. The dry ice conveying pipe 8 is connected to the dry ice main pipe 9. The dry ice main pipe 9 is installed around the middle part of the spiral ascending section of the conveying belt 2. The dry ice main pipe 9 is provided with the dry ice branch pipe 10. The outlet of the dry ice branch pipe 10 is directed towards the conveying belt 2. The dry ice conveying pipe 8, the dry ice main pipe 9, and the dry ice branch pipe 10 are the flexible pipeline described above.

[0064] Specifically, the liquid carbon dioxide storage device 5 is a Dewar flask, which is arranged outside the spiral quick freezer main body 1. The liquid carbon dioxide is transported in the dry ice conveying pipe 8 in the form of flow state dry ice with gas and solid phases. A hole is opened in the wall of the spiral quick freezer main body 1. The dry ice conveying pipe 8 passes through the hole into the inside of the library body.

[0065] As a preferred embodiment of the present application, the outer side of each dry ice branch pipe 10 is provided with an infrared temperature sensor 11 for measuring the temperature of the object to be frozen on the conveying belt 2.

[0066] As a preferred embodiment of the present application, referring to Figure 2 , the dry ice branch pipe 10 is provided with a switch valve 101, and the dry ice branch pipe 10 is provided with at least one dry ice nozzle 102, and the bottom baffle 103 is installed on the lower side of the conveying belt 2 to receive the dry ice powder, so as to ensure that the upper surface and the lower surface of the fish body are cooled by the dry ice sublimation.

[0067] As a preferred embodiment of the present application, the number of dry ice nozzles 102 on the dry ice branch pipe 10 is multiple, and the multiple dry ice nozzles 102 are arranged at intervals on the dry ice branch pipe 10, and the interval of the nozzles can ensure that the dry ice spraying completely covers the surface of the fish body.

[0068] After the flow regulating valve 6 is opened, the liquid carbon dioxide flows out of the Dewar bottle, enters the spiral quick freezer main body 1 through the dry ice conveying pipe 8, and the liquid carbon dioxide in the conveying pipe is converted into the flow state dry ice, that is, the carbon dioxide gas wraps the dry ice powder for transportation; the flow state dry ice is transferred from the dry ice conveying pipe 8 to the dry ice main pipe 9, the dry ice main pipe 9 is fixed along the outer edge of the spiral ascending conveying belt and is located in the middle of the ascending section of the conveying belt; the dry ice main pipe 9 is provided with dry ice branch pipes 10 at every interval, which are perpendicular to the running direction of the conveying belt, and the dry ice branch pipes 10 are provided with nozzles, and the flow state dry ice is sprayed to the surface of the fish body through the nozzles; an infrared temperature sensor 11 is installed near each dry ice branch pipe 10 for non-contact temperature measurement of the fish body.

[0069] Referring to Figure 1 and Figure 2 , a spiral quick freezer includes a spiral quick freezer main body 1, a conveying belt 2, a fan 3, an evaporator 4, and the above-mentioned spiral quick freezer dry ice spraying device. The above-mentioned spiral quick freezer dry ice spraying device can be directly applied to the existing spiral quick freezer, and the spiral quick freezer already put into use on the market can be low-cost transformed; when the air cooling can meet the freezing demand, the dry ice spraying device is closed, and the spiral quick freezer can normally operate as a conventional spiral quick freezer; when the air cooling cannot meet the freezing demand, the dry ice spraying device is opened, and the flow state dry ice provides additional cold energy to accelerate freezing and improve the freezing quality of food.

[0070] The present application also proposes a control method for the above-mentioned spiral quick freezer dry ice spraying device, including a starting process control method, an adjusting process control method, and a closing process control method.

[0071] Referring to Figure 4 , the starting process control method includes the following steps:

[0072] When the spiral freezer is started, the temperature in the freezer begins to decrease, and the temperature Tin is read in real time to determine whether it reaches the set value. When the temperature in the freezer reaches the set temperature, the readings of the infrared temperature sensors are started to be read. Since the infrared temperature sensors are arranged along the conveying belt in the running direction, the temperature distribution along the conveying belt can be measured. When there is no fish on the conveying belt, the temperature of the infrared temperature sensors is the temperature in the freezer; when there is fish on the conveying belt, the temperature of the infrared temperature sensors is the temperature of the fish.

[0073] When the conveying belt starts to feed, the fish moves along the conveying belt, and the temperature change of the infrared temperature sensor installed at the first position is monitored in real time. If the temperature is the temperature in the freezer, the fish has not entered the dry ice pipeline arrangement section. When the temperature deviates from the temperature in the freezer, it means that the first fish has started to enter the dry ice pipeline arrangement section. At this time, the flow regulating valve is slowly opened to prepare to open the dry ice spraying system. In order to make the dry ice spraying accurately act in the temperature interval of T1 to T2, the reading of the infrared temperature sensor closest to the first fish is read in real time. At this time, the first fish has passed through the conveying belt area, and the infrared temperature sensor readings are all fish temperatures. In the conveying belt area where the first fish has not arrived, the infrared temperature sensor readings are the temperature in the freezer, so that the position of the first fish can be determined. When the temperature of the first fish is monitored to reach T1, the on-off valve of the dry ice spraying branch closest to the fish position is opened. Subsequently, the rear spraying branch is opened with a delay, that is, the on-off valve of the next spraying branch is opened every △t time, so as to ensure that the area where the first fish has not arrived is not sprayed, and the area where the first fish has arrived is sprayed. The temperature of the first fish is monitored in real time, and when the temperature reaches T2, the opening of the remaining on-off valves of the spraying branches is stopped. At this time, the branches in the temperature interval of T1 to T2 have all been opened, and the branches in the remaining temperature intervals are in a closed state.

[0074] The starting process control method ensures that only the area with fish is sprayed during the starting process, and the area without fish is not sprayed; the fish in the temperature interval of T1 to T2 is sprayed, and the fish outside the temperature interval is not sprayed, thereby avoiding the waste of dry ice in the starting stage and realizing the matching of the supply and demand of dry ice in the starting process.

[0075] Referring to Figure 5 , the adjusting process control method comprises the following steps:

[0076] When the feed amount changes, for example, the fish size, fish species, fish density, etc. changes, the opening and closing of the dry ice spraying branch needs to be re-adjusted. First, according to the position of the first dry ice branch n that is currently being sprayed, the fish temperature at this position is read, and it is judged whether the fish temperature is T1; if the fish temperature is greater than T1, it means that the spraying starts too early, so the switch valve of the first branch n that is currently being sprayed is closed; if the fish temperature is less than T1, it means that the spraying starts too late, so the switch valve of the previous spraying branch n-1 is opened; if the fish temperature is equal to T1, the position of starting spraying is kept unchanged. The above adjustment is repeated until the fish temperature is equal to T1. Subsequently, according to the position of the last spraying branch m, the fish temperature at this position is read, and it is judged whether the fish temperature is T2; if the fish temperature is greater than T2, it means that the spraying ends too early, so the switch valve of the next spraying branch m+1 is opened; if the fish temperature is less than T2, it means that the spraying ends too late, so the switch valve of the last branch m that is currently being sprayed is closed; if the fish temperature is equal to T2, the position of ending spraying is kept unchanged. The above adjustment is repeated until the fish temperature is equal to T2. Finally, the number of branches that are currently being sprayed is counted, in order to ensure that the flow of each branch remains unchanged, the flow regulating valve opening of the main road needs to be adjusted until the flow of the main road is equal to the sum of the flow required by each branch. At this point, the adjustment is complete, the branches in the temperature interval of T1 to T2 have all been opened, and the branches in the remaining temperature interval are in the closed state. The adjustment process control method can ensure that when the working condition changes during the operation of the spiral freezer, the dry ice spraying system can follow the change of the working condition and adjust in real time, so that the dry ice spraying stably acts on the temperature interval of T1 to T2, and the supply and demand of dry ice during operation are matched.

[0077] Referring to Figure 6 , the closing process control method comprises the following steps:

[0078] When the conveying belt stops feeding, according to the reading of the infrared temperature sensor, the position of the last fish is determined, the infrared temperature sensor before the position is the library temperature, and the infrared temperature sensor after the position is the fish temperature. According to the position of the first branch n that is currently being sprayed, the reading T of the infrared temperature sensor at this position is read, if T is equal to the library temperature Tin, it means that there is no fish at this position, so the corresponding branch switch valve is closed. Then the next branch is judged, after the fish passes, the reading of the infrared temperature sensor of the branch will also become the library temperature, so the branch switch valve is closed. This cycle of operation is repeated until all the branches that are currently being sprayed are closed. Then the flow regulating valve is slowly closed, and the dry ice spraying device is completely closed.

[0079] The closing process control method ensures that only the area with fish is sprayed in the closing process, and the area without fish is not sprayed, thereby avoiding dry ice waste in the closing stage, and achieving matching of the dry ice supply amount and the demand amount in the closing process.

[0080] The above is only an embodiment of the present application, and does not limit the protection scope of the present application. Any equivalent structure or equivalent flow transformation made by using the content of the present application specification and drawings, or direct or indirect application in other related system fields, are also included in the protection scope of the present application.

Claims

1.A spiral freezer dry ice spraying device, characterized in that: it comprises a liquid carbon dioxide storage device (5), a flow regulating valve (6), a flow meter (7), a dry ice conveying pipe (8), a dry ice main pipe (9), a dry ice branch pipe (10), and an infrared temperature sensor (11); the liquid carbon dioxide storage device (5) is connected with the dry ice conveying pipe (8), the flow regulating valve (6) and the flow meter (7) are arranged in the dry ice conveying pipe (8), the dry ice conveying pipe (8) is connected with the dry ice main pipe (9), the dry ice main pipe (9) is installed around the middle part of the spiral ascending section of the conveying belt (2), the dry ice main pipe (9) is provided with the dry ice branch pipe (10), and the outlet of the dry ice branch pipe (10) is arranged to spray toward the conveying belt (2). 2.The spiral freezer dry ice spraying device according to claim 1, characterized in that: the thermal insulation layer (81) is made of soft thermal insulation material. 3.The spiral freezer dry ice spraying device according to claim 2, characterized in that: the rigid outer layer (82) is made of rigid material to ensure the structural strength and pressure resistance of the pipe. 4.The spiral freezer dry ice spraying device according to claim 1, characterized in that: the soft filler layer (83) is made of soft material with loose pores to enhance the heat insulation effect of the pipe and improve the pressure resistance of the pipe. 5.A spiral freezer, characterized in that: it comprises a spiral freezer main body (1), a conveying belt (2), a fan (3), an evaporator (4), and the spiral freezer dry ice spraying device according to any one of claims 1-4. 6.A control method for the spiral freezer dry ice spraying device according to any one of claims 1-4, characterized in that: it comprises a start process control method, an adjustment process control method, and a shutdown process control method. 7.The start process control method according to claim 6, characterized in that: it comprises the following steps: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ S101: After the spiral freezer is started, the library temperature begins to decrease, the library temperature Tin is read in real time, whether the set value is reached is judged, if not, S101 is repeated; if reached, S102 is entered; S102: The temperature of all infrared temperature sensors (11) arranged along the conveying belt (2) is read, whether the temperature value of the first infrared temperature sensor (11) along the running direction of the conveying belt (2) is equal to the library temperature Tin is judged; if equal, S102 is repeated; if not equal, S103 is entered; S103: The flow regulating valve (6) is slowly opened, and S104 is entered; S104: The temperature value of the infrared temperature sensor (11) closest to the first to-be-frozen object behind the first to-be-frozen object is read as the to-be-frozen object temperature, whether the to-be-frozen object temperature reaches the upper limit temperature set value T1 of the dry ice spraying section is judged, if not reached, S104 is repeated; if reached, S105 is entered; S105: The on-off valve (101) of the spraying branch closest to the current position of the first to-be-frozen object is opened, and S106 is entered; S106: Every△t time, the on-off valve (101) of the next spraying branch is opened,△t is equal to the time from when the first to-be-frozen object enters the spraying range of a branch to when the first to-be-frozen object leaves the spraying range of the branch, the temperature value of the infrared temperature sensor (11) closest to the first to-be-frozen object behind the first to-be-frozen object is read as the to-be-frozen object temperature, whether the first to-be-frozen object temperature reaches the lower limit temperature set value T2 of the dry ice spraying section is judged, if not reached, S106 is repeated; if reached, S107 is entered; S107: Stop opening the on-off valve (101) of the remaining spraying branch; the dry ice spraying device is started and completed; The adjusting process control method comprises the following steps: S201: When the size, type and density parameters of the to-be-frozen object change, causing the working condition to change, the to-be-frozen object temperature at the first spraying branch n position is read, and the size relationship between the to-be-frozen object temperature and the upper limit temperature set value T1 of the dry ice spraying section is judged; if the to-be-frozen object temperature is greater than T1, the on-off valve (101) of the first spraying branch n is closed, and S201 is repeated; if the to-be-frozen object temperature is less than T1, the on-off valve (101) of the previous spraying branch n-1 is opened, and S201 is repeated; if the to-be-frozen object temperature is equal to T1, S202 is entered; S202: The to-be-frozen object temperature at the last spraying branch m position is read, and the size relationship between the to-be-frozen object temperature and the lower limit temperature set value T2 of the dry ice spraying section is judged; if the to-be-frozen object temperature is greater than T2, the on-off valve (101) of the next spraying branch m+1 is opened, and S202 is repeated; if the to-be-frozen object temperature is less than T2, the on-off valve (101) of the last spraying branch m is closed, and S202 is repeated; if the to-be-frozen object temperature is equal to T2, S203 is entered; S203: The number of spraying branches is counted, and S204 is entered; S204: Adjust the opening of the flow regulating valve (6) in the main path, determine whether the flow in the main path is equal to the total flow required by each branch; if not, repeat S204; if yes, the dry ice spraying device is adjusted to completion; The closing process control method comprises the following steps: S301: When the feeding is stopped, read the temperature value T of the infrared temperature sensor (11) at the first spraying branch n position, determine whether T is equal to the library temperature Tin; if not, repeat S301; if yes, enter S302; S302: Close the on-off valve (101) of the first spraying branch n, and enter S303; S303: Determine whether all spraying branches are closed; if not, repeat S301; if yes, enter S304. S304: Slowly close the flow regulating valve (6), and the dry ice spraying device is closed to completion.

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