A head removal and cleaning device and method for processing lobster tails

Abstract

The present invention relates to the field of fresh shrimp processing equipment, and discloses a head removal and cleaning device and method for lobster tail processing. Among them, a head removal and cleaning device for lobster tail processing includes a frame, a clamp, a cutter, a cleaning component and a multifunctional processing box. The multifunctional processing box is provided with a blanching chamber and a drying chamber that are isolated from each other. The crayfish is fixed to the clamp, the cutter can automatically cut off the shrimp head and shrimp tail, the cleaning component sprays water to wash away the blood stains on the cut part, the shrimp head falls into the drying chamber, and then the clean shrimp tail is put into the blanching chamber. In addition to being able to realize the basic automatic head removal function, the multifunctional processing box can also blanch the shrimp tail and dry the shrimp head simultaneously. A lobster tail processing head removal and cleaning method using the above device includes the following steps: S1 hanging → S2 head removal and cleaning → S3 blanching → S4 drying. The present application has the effect of further post-processing the shrimp head and shrimp tail separately to improve the functional diversity of the equipment.

Description

Technical Field

[0001] The invention relates to the field of fresh shrimp processing equipment, in particular to a head-removing and cleaning device and method for lobster tail processing. Background Art

[0002] Crayfish is a food that is deeply loved by consumers, but it is difficult to handle. The shrimp head concentrates the main organs and metabolites of the shrimp, and contains many ingredients that are harmful to the human body. It is not only inedible but also large in size and weight. In order to make it more convenient for consumers to eat, the shrimp head is usually removed first when making shrimp delicacies or processing in factories, leaving only the shrimp tail for consumers to buy. In addition to the inefficient manual method, the common way to remove the shrimp head is the mechanical method.

[0003] The existing lobster head removal equipment can refer to the Chinese patent document with the announcement number CN207927685U. The above patent document discloses a prawn head removal device, which separates the prawn head and the prawn tail by placing the prawns in a prawn tank and utilizing the relative reverse rotation of two motors; then the prawn head and the prawn tail are collected separately; and a water pipe is provided to flush the processing table and the prawn tail to make the processing environment and the finished product cleaner.

[0004] However, shrimp heads are often made into shrimp powder and then recycled as feed supplementary materials or planting waste, which has a relatively large utilization value. The above device only separates the shrimp heads from the shrimp tails, and fails to carry out subsequent treatment on these two parts with different uses in a targeted manner. Summary of the invention

[0005] In order to further post-process the shrimp heads and shrimp tails separately and improve the diversity of equipment functions, the present application provides a head removal and cleaning device and method for lobster tail processing.

[0006] On the one hand, the present application provides a head removal and cleaning device for lobster tail processing, which adopts the following technical solution:

[0007] A head removal and cleaning device for lobster tail processing, comprising a frame, a cleaning assembly and a multifunctional processing box, wherein a clamp is provided on the top of the frame, a cutter is provided on the bottom of the frame, and the multifunctional processing box is located below the frame;

[0008] The clamp is used to clamp and fix the crayfish;

[0009] The cutter is used to automatically separate the shrimp head and the shrimp tail;

[0010] The cleaning component is used for spraying water to wash the shrimp tails;

[0011] The multifunctional processing box is provided with a boiling chamber and a drying chamber which are isolated from each other. The boiling chamber is used for boiling shrimp tails, and the drying chamber is used for drying shrimp heads.

[0012] By adopting the above technical solution, in addition to being able to realize the basic automatic head removal function, the multifunctional processing box can also process the shrimp tails and discarded shrimp heads obtained after head removal separately for subsequent processing. After being rinsed by the cleaning component, the shrimp tails enter the blanching chamber and are blanched for a short time, which can make the shrimp meat products have a more crispy, elastic and delicious taste. At the same time, the discarded shrimp heads fall into the drying chamber and are dried so that they can be subsequently ground into shrimp powder for recycling. This device can perform different processing on the product and waste materials separately after head removal, integrating different functions, thereby greatly improving the functional diversity of the head removal equipment.

[0013] Furthermore, a rotating shaft is vertically rotatably arranged in the drying chamber, a toggle member is fixedly connected to the rotating shaft near the bottom, one end of the toggle member is horizontally cantilevered and fixed to the outer peripheral wall of the rotating shaft, and the toggle member is used to turn over the shrimp heads.

[0014] By adopting the above technical solution, the toggle member can flatten the shrimp heads accumulated in the drying chamber by rotating with the rotating shaft, and can also turn the shrimp heads during drying, thereby making the drying effect more uniform.

[0015] Furthermore, a screw is vertically rotatably arranged in the blanching chamber, a sleeve is arranged outside the screw, the screw is threadedly connected to the sleeve, a mesh screen is fixedly connected to the outer peripheral wall of the sleeve, one end of the mesh screen away from the sleeve is vertically slidably connected to the inner wall of the blanching chamber, and the mesh screen is used to hold shrimp tails.

[0016] By adopting the above technical solution, a mesh screen is fixedly installed on the sleeve to hold the shrimp tails, and the other end of the mesh screen is slidably connected to the inner wall of the boiling chamber, thereby limiting the rotation of the mesh screen, so that the mesh screen can be automatically raised and lowered by driving the screw rod to rotate. When boiling the shrimp tails, the mesh screen can prevent the shrimp tails from scattering around under the rolling action of boiling water and being inconvenient to salvage, thereby preventing the boiling time from being too long.

[0017] Furthermore, the boiling chamber is overlapped above the drying chamber, the boiling chamber and the drying chamber are sealed by a flange, the rotating shaft is rotatably inserted in the flange, the rotating shaft is coaxially fixed with the screw, and a driving motor is provided at the bottom of the rotating shaft, and the driving motor is used to drive the rotating shaft to rotate.

[0018] By adopting the above technical solution, the boiling chamber is overlapped and arranged above the drying chamber, and the rotating shaft and the screw are fixed coaxially, so that the boiling chamber and the drying chamber are synchronously linked, and a single power source of the driving motor can simultaneously drive the mesh screen and the toggle member to operate, thereby achieving the effect of simplifying the device.

[0019] Furthermore, a feed opening is provided on the top of the drying chamber, and the feed opening is directly opposite to the cutter so that the shrimp heads fall into the drying chamber after cutting.

[0020] By adopting the above technical solution, the feed port facing the cutter can be arranged so that the shrimp heads can fall directly into the drying chamber after being cut off, and the feed port can also serve as a water vapor outlet for the drying chamber.

[0021] Furthermore, the cleaning assembly includes a plurality of nozzles, which are arranged around the clamp and are used to spray water to clean the crayfish.

[0022] By adopting the above technical solution, multiple nozzles surround the clamp to clean the shrimp tail, which can clean it from multiple angles and in all directions, reduce dead corners, and improve the cleaning effect.

[0023] Furthermore, the liquid sprayed by the cleaning component is a mixture of salt water and white vinegar.

[0024] By adopting the above technical solution, the shrimp tails are rinsed with a mixture of white vinegar and salt water. In addition to washing away impurities and blood stains, the shrimp tails can also be pickled to play a role in disinfection, sterilization, and deodorization, thereby improving the taste and hygiene of the shrimp tails.

[0025] Furthermore, the cutter is an electric scissors, which is fixedly mounted on the frame. A distance sensor is provided on the side wall of the frame. The distance sensor is electrically connected to the electric scissors, and the distance sensor is used to control the start and stop of the electric scissors.

[0026] By adopting the above technical solution, an electric scissors controlled by a distance sensor is set as a cutter. When there is no crayfish hanging on the clamp, the distance sensor measures the distance between the opposite side walls of the rack as a. When a crayfish is hung on the clamp, the shrimp head is blocked between the distance sensor and the side wall of the rack. At this time, the distance measured by the distance sensor is b. The electric scissors can automatically determine the cutting time according to whether there is a crayfish hanging on the clamp, thereby eliminating the need to manually cut off the shrimp head.

[0027] On the other hand, the present application provides a lobster tail processing, head removal and cleaning method, which adopts the following technical solution:

[0028] A method for processing and cleaning lobster tails, using the above-mentioned head removal and cleaning device for processing lobster tails, comprises the following steps:

[0029] S1: Hanging: using the clamp to clamp and fix the tail of the crayfish, so that the crayfish is hung upside down above the cutting knife;

[0030] S2: removing the head and cleaning: removing the shrimp head, and the cleaning component sprays water to rinse and clean the shrimp tail, and cleans the connection between the shrimp tail and the shrimp head;

[0031] S3 blanching: removing the cleaned shrimp tails from the fixture and placing them into the blanching chamber of the multifunctional processing box, blanching the shrimp tails in boiling water for 2-3 minutes, and then picking up the shrimp tails;

[0032] S4 drying: using the drying chamber of the multifunctional processing box to dry the cut shrimp heads, taking out the dried shrimp heads, and crushing the shrimp heads into shrimp powder;

[0033] Wherein, step S3 and step S4 are performed simultaneously.

[0034] By adopting the above technical solution, hanging crayfish upside down makes it easier for the shrimp heads to fall off. Using the above head removal and cleaning device to integrate the processing of crayfish can achieve crayfish head removal, cleaning, blanching of shrimp tails to lock in freshness, and drying of waste shrimp heads at one time, thereby achieving simultaneous post-processing of shrimp heads and shrimp tails, respectively, and improving the processing efficiency of crayfish.

[0035] Furthermore, when performing step S1, the clamp is used to clamp the clip in the center of the crayfish tail; when performing step S3, the shrimp tail is held and pulled downward until the nail plate in the center breaks.

[0036] By adopting the above technical solution, since the scale at the center of the crayfish's tail is connected to the shrimp line, the crayfish is hung upside down by clamping the scale at the center. In step S3, the scale is pulled down by holding the shrimp tail to break off the scale, and the shrimp line can be pulled out while removing the shrimp tail. This is time-saving and efficient, and the degree of refinement of the shrimp tail processing is further improved, making the product more popular.

[0037] In summary, the present application includes at least one of the following beneficial technical effects:

[0038] 1. By sequentially arranging the clamp, cleaning component, cutter and multifunctional processing box from top to bottom, in addition to being able to realize the basic automatic de-heading function, the multifunctional processing box with a blanching chamber and a drying chamber can also blanch the shrimp tails and dry the shrimp heads at the same time. Thus, the de-heading device integrates different functions, which greatly improves the functional diversity of the de-heading equipment and improves the processing efficiency of crayfish;

[0039] 2. The boiling chamber is overlapped and arranged above the drying chamber, and the screw of the boiling chamber is coaxially fixed with the rotating shaft of the drying chamber, so that the boiling chamber and the drying chamber are synchronously linked, and a driving motor power source can simultaneously drive the mesh screen and the toggle member to operate, thereby achieving the effect of simplifying the device;

[0040] 3. Through the steps of hanging S1 → deheading and cleaning S2 → blanching S3 → drying S4, the above-mentioned device is used to simultaneously perform steps S3 and S4, which can achieve the deheading, cleaning, blanching of shrimp tails to lock in freshness of crayfish and drying of waste shrimp heads at one time, and realize the use of the same device to process products and waste materials separately and simultaneously, thereby improving the processing efficiency of crayfish and being beneficial to environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of a head removal and cleaning device for processing lobster tails according to Example 1 of the present application.

[0042] Figure 2 It is a schematic diagram of the internal structure of the multifunctional processing box.

[0043] Figure 3 It is a schematic diagram of the cutter structure.

[0044] Figure 4 This is a step flow chart of Example 2 of the present application.

[0045] Description of reference numerals:

[0046] 1. Frame; 2. Clamp; 21. Nail teeth; 3. Electric scissors; 4. Cleaning assembly; 41. Nozzle; 5. Multi-function processing box; 51. Boiling chamber; 511. Screw; 512. Sleeve; 513. Screen; 52. Drying chamber; 521. Rotating shaft; 522. Driving piece; 523. Feeding port; 53. Driving motor; 6. Distance sensor. DETAILED DESCRIPTION

[0047] The following is combined with Figure 1-4 The technical solution of this application is described clearly and completely.

[0048] Example 1

[0049] Embodiment 1 of the present application discloses a head removal and cleaning device for lobster tail processing.

[0050] Reference Figure 1 , Figure 2 A head removal and cleaning device for lobster tail processing includes a frame 1, a clamp 2, a cutter, a cleaning component 4 and a multifunctional processing box 5. The clamp 2 and the cutter are fixedly installed on the top and bottom of the frame 1 respectively, the cleaning component 4 is arranged around the clamp 2, and the multifunctional processing box 5 is placed directly below the frame 1. The multifunctional processing box 5 is provided with a boiling chamber 51 and a drying chamber 52 which are isolated from each other.

[0051] The crayfish is fixed to the clamp 2, the cutter can automatically cut off the shrimp head and shrimp tail, the cleaning component 4 sprays water to wash away the blood stains on the cut part, the shrimp head falls into the drying chamber 52, and then the clean shrimp tail is put into the boiling chamber 51. The shrimp tail enters the boiling chamber 51 and is blanched for a short time, which can make the shrimp meat product have a more crispy and delicious taste; at the same time, the discarded shrimp head falls into the drying chamber 52 and is dried, so that it can be ground into shrimp powder for recycling.

[0052] In addition to realizing the basic automatic head removal function, this device can also process the shrimp tails as products and the waste shrimp heads separately at the same time, thereby greatly improving the functional diversity of the head removal equipment and improving the processing efficiency of crayfish.

[0053] Reference Figure 1 In this embodiment, the lever-type clamp 2 is preferably pressed to clamp the lobster under the elastic force of the torsion spring, which is convenient for taking. The side of the clamp 2 that contacts the lobster is also provided with protruding nail teeth 21. The clamp 2 is fixedly installed in the center of the top of the frame 1 through a connecting rod that protrudes outward. Since the tail of the crayfish has a thin scale, it is easier to clamp. Therefore, the tail of the crayfish is fixed on the clamp 2, and the crayfish is hung upside down above the cutter. The height of the connection between the shrimp head and the shrimp tail is roughly flush with the cutter.

[0054] Reference Figure 1 The cleaning component 4 includes a plurality of nozzles 41, and the plurality of nozzles 41 are arranged around the fixture 2, so that the shrimp tails on the fixture 2 can be cleaned in all directions at multiple angles. Dead angles are reduced and the cleaning effect is improved. The liquid used for cleaning is preferably a mixture of salt water and white vinegar. In addition to flushing impurities and blood stains, the shrimp tails can also be pickled to play the role of disinfection, sterilization, and deodorization, thereby improving the taste and hygiene of the shrimp tails.

[0055] Reference Figure 3 The cutter is preferably an electric scissors 3. Since the crayfish is suspended, there is no fulcrum when cutting. If an ordinary knife is used, the head is easily displaced due to the force on one side. The electric scissors 3 can generate shearing force inward from both sides, so as to accurately and quickly cut the shrimp head and shrimp tail. In order to realize the automatic operation of the electric scissors 3, a distance sensor 6 is provided on the side wall of the frame 1, and the distance sensor 6 is electrically connected to the electric scissors 3. When there is no crayfish hanging on the clamp 2, the distance sensor 6 measures the distance between the opposite side walls of the frame 1 as a, and when there is a crayfish hanging on the clamp 2, the shrimp head is blocked between the distance sensor 6 and the side wall of the frame 1. At this time, the distance measured by the distance sensor 6 is b. The electric scissors 3 can automatically judge the cutting time according to whether there is a crayfish hanging on the clamp 2, so that there is no need to manually cut off the shrimp head.

[0056] Reference Figure 1 , Figure 2The multifunctional processing box 5 is generally cylindrical in shape, and is divided into two layers, an upper layer and a lower layer. The boiling chamber 51 is located above the drying chamber 52, and the bottom area of ​​the boiling chamber 51 is slightly smaller than that of the drying chamber 52. The top wall of the drying chamber 52 outside the boiling chamber 51 is provided with a feed port 523, which is directly opposite to the cutter so that the shrimp heads can fall directly into the drying chamber 52 after cutting. The bottom wall of the boiling chamber 51 also serves as the top wall of the drying chamber 52.

[0057] Reference Figure 2 A rotating shaft 521 is vertically rotatably arranged in the center of the drying chamber 52, and a rod-shaped or strip-shaped toggle member 522 is fixedly connected near the bottom of the rotating shaft 521. One end of the toggle member 522 is horizontally suspended and fixed to the outer peripheral wall of the rotating shaft 521. The toggle member 522 rotates with the rotating shaft 521 to flatten the shrimp heads piled up near the feed inlet 523 on the bottom wall of the drying chamber 52, and can also play a role in turning the shrimp heads during drying, so that the drying effect is more uniform. A driving motor 53 is also installed on the outer side of the bottom wall of the multifunctional processing box 5. The output shaft of the driving motor 53 is coaxially fixed with the bottom end of the rotating shaft 521 to drive the rotating shaft 521 to rotate. The inner wall of the drying chamber 52 is also paved with a drying device. The drying device has no substantial difference from the prior art, and the structure is not repeated here.

[0058] Reference Figure 2 A screw 511 is vertically rotatably arranged in the blanching chamber 51, and a sleeve 512 is disposed on the outer cover of the screw 511, and the screw 511 is threadedly connected to the sleeve 512. A mesh screen 513 is fixedly connected to the outer peripheral wall of the sleeve 512, and one end of the mesh screen 513 away from the sleeve 512 is vertically slidably connected to the inner wall of the blanching chamber 51, thereby limiting the rotation of the mesh screen 513, so that driving the screw 511 to rotate can drive the mesh screen 513 to automatically rise and fall. A conventional heating device is arranged on the inner wall of the blanching chamber 51, and water is added into the blanching chamber 51, heated to boiling, and then used for blanching. When blanching the shrimp tails, the shrimp tails are put into the mesh screen 513, and the mesh screen 513 can prevent the shrimp tails from scattering around under the rolling action of the boiling water and being inconvenient to salvage, so as to avoid the blanching time being too long.

[0059] A communication port is provided between the boiling chamber 51 and the drying chamber 52, and a flange seal is provided on the communication port. A rotating shaft 521 is rotatably inserted in the center of the flange, and the top of the rotating shaft 521 extends upward and is coaxially fixed with the screw 511. The boiling chamber 51 and the drying chamber 52 are synchronously linked, and a driving motor 53 can simultaneously drive the mesh screen 513 and the toggle member 522 to operate with one power source, thereby achieving the effect of simplifying the device.

[0060] Example 2

[0061] Example 2 of the present application discloses a method for processing, de-heading and cleaning lobster tails, which is used in conjunction with the device in Example 1.

[0062] Reference Figure 4A lobster tail processing, head removal and cleaning method comprises the following steps: S1 hanging → S2 head removal and cleaning → S3 blanching → S4 drying, wherein (combined with Figure 1 ) Step S3 and step S4 are performed simultaneously using the multifunctional processing box 5. The specific operation of each step is as follows:

[0063] S1 hanging: Use the clamp 2 to clamp and fix the crayfish tail, so that the crayfish is hung upside down above the cutter. Preferably, the clamp 2 clamps the clip in the center of the crayfish tail.

[0064] S2 removes the head and cleans: removes the shrimp head, and the cleaning component 4 sprays water to rinse and clean the shrimp tail, and cleans the connection between the shrimp tail and the shrimp head.

[0065] S3: Blanching: Remove the cleaned shrimp tail from the clamp 2, hold the shrimp tail and pull it down until the nail plate in the center breaks. Since the nail plate in the center of the crayfish tail is connected to the shrimp line, the crayfish is hung upside down by clamping the nail plate in the center with the clamp 2. In step S3, the shrimp tail can be pulled down by hand to break the nail plate, and the shrimp line can be pulled out while removing the shrimp tail, which is time-saving and efficient, and the degree of refinement of shrimp tail processing is further improved, making the product more popular. Then put the shrimp tail into the boiling chamber 51 of the multifunctional processing box 5, blanch the shrimp tail in boiling water for 2-3 minutes, and then pick up the shrimp tail.

[0066] S4 Drying: Use the drying chamber 52 of the multifunctional processing box 5 to dry the cut shrimp heads, take out the dried shrimp heads, and grind the shrimp heads into shrimp powder.

[0067] Hanging crayfish upside down makes it easier for the shrimp heads to fall off. Using the above-mentioned head removal and cleaning device to integrate the processing of crayfish can achieve crayfish head removal, cleaning, blanching of shrimp tails to lock in freshness and drying of waste shrimp heads at one time, thereby achieving simultaneous post-processing of shrimp heads and shrimp tails, respectively, and improving the processing efficiency of crayfish.

[0068] The above are all preferred embodiments of the present application. Obviously, the embodiments described above are only preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made by ordinary technicians in this field based on the structure, shape, and principle of the present application without making any creative work should be covered within the protection scope of the present application.

Claims

1. A head removal and cleaning device for lobster tail processing, characterized in that: It comprises a frame (1), a cleaning component (4) and a multifunctional processing box (5), wherein a clamp (2) is provided on the top of the frame (1), a cutter is provided on the bottom of the frame (1), and the multifunctional processing box (5) is located below the frame (1); The clamp (2) is used to clamp and fix the crayfish; The cutter is used to automatically separate the shrimp head and the shrimp tail; The cleaning component (4) is used for spraying water to wash the shrimp tails; The multifunctional processing box (5) is provided with a boiling chamber (51) and a drying chamber (52) which are isolated from each other. The boiling chamber (51) is used for boiling shrimp tails, and the drying chamber (52) is used for drying shrimp heads. A rotating shaft (521) is vertically rotatably arranged in the drying chamber (52), a toggle member (522) is fixedly connected to the rotating shaft (521) near the bottom, one end of the toggle member (522) is horizontally cantilevered and fixed to the outer peripheral wall of the rotating shaft (521), and the toggle member (522) is used to turn over the shrimp heads; A screw rod (511) is vertically rotatably arranged in the blanching chamber (51), a sleeve (512) is disposed on the outer shell of the screw rod (511), the screw rod (511) is threadedly connected to the sleeve (512), a mesh screen (513) is fixedly connected to the outer peripheral wall of the sleeve (512), one end of the mesh screen (513) away from the sleeve (512) is vertically slidably connected to the inner wall of the blanching chamber (51), and the mesh screen (513) is used to contain shrimp tails; The scalding chamber (51) is overlapped and arranged above the drying chamber (52); the scalding chamber (51) and the drying chamber (52) are sealed by a flange; the rotating shaft (521) is rotatably inserted in the flange; the rotating shaft (521) is coaxially fixed with the screw (511); a driving motor (53) is provided at the bottom of the rotating shaft (521); the driving motor (53) is used to drive the rotating shaft (521) to rotate.

2. The head removal and cleaning device for lobster tail processing according to claim 1, characterized in that: The drying chamber (52) has a feed opening (523) at the top, and the feed opening (523) is directly opposite to the cutter so that the shrimp heads fall into the drying chamber (52) after cutting.

3. The head removal and cleaning device for lobster tail processing according to claim 1, characterized in that: The cleaning assembly (4) comprises a plurality of spray heads (41), the plurality of spray heads (41) being arranged around the clamp (2), and the spray heads (41) being used to spray water to clean the crayfish.

4. The head-removing and cleaning device for lobster tail processing according to claim 3, characterized in that: The liquid sprayed by the cleaning component (4) is a mixture of salt water and white vinegar.

5. The head-removing and cleaning device for lobster tail processing according to claim 1, characterized in that: The cutter is an electric scissors (3), the electric scissors (3) are fixedly mounted on the frame (1), a distance sensor (6) is provided on the side wall of the frame (1), the distance sensor (6) is electrically connected to the electric scissors (3), and the distance sensor (6) is used to control the start and stop of the electric scissors (3).

6. A method for processing, removing and cleaning lobster tails, characterized in that: Using the head removal and cleaning device according to any one of claims 1 to 5 comprises the following steps: S1 hanging: using the clamp (2) to clamp and fix the crayfish tail, so that the crayfish is hung upside down above the cutting knife; S2: removing the head and cleaning: removing the shrimp head, and the cleaning component (4) sprays water to rinse and clean the shrimp tail, and cleans the connection between the shrimp tail and the shrimp head; S3 blanching: removing the cleaned shrimp tails from the clamp (2) and placing them into the blanching chamber (51) of the multifunctional processing box (5), blanching the shrimp tails in boiling water for 2-3 minutes, and then picking up the shrimp tails; S4 drying: using the drying chamber (52) of the multifunctional processing box (5) to dry the cut shrimp heads, taking out the dried shrimp heads, and crushing the shrimp heads into shrimp powder; Wherein, step S3 and step S4 are performed simultaneously.

7. The method for processing, head removal and cleaning of lobster tails according to claim 6, characterized in that: When performing step S1, the clamp (2) is used to clamp the clip at the center of the crayfish tail; when performing step S3, the crayfish tail is held and pulled downward until the nail plate at the center breaks.

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