Device and process for weighing live shrimp

Abstract

The present invention discloses a device for weighing live shrimp, both for harvesting the animal and for transferring the animal, wherein the device comprises a main support structure, a secondary support structure and a weighing box that is opened and closed by a gate controlled by a four-bar mechanism. The present invention further relates to a weighing process that uses the device of the invention. International patent classification: Weighing apparatus or methods using mechanical computational means (G01G 13 / 41) and support or suspension of weighing platforms (G01G 21 / 23). The invention belongs to the technical field of mechanics.

Description

[0001] DEVICE AND PROCESS FOR WEIGHING LIVE SHRIMP

[0002] TECHNICAL FIELD

[0003] The present invention belongs to the aquaculture field, particularly to the process of shrimp farming and production, and consists of a device and process for weighing live shrimp, both for harvest and transfer animals.

[0004] TECHNICAL BACKGROUND

[0005] Shrimp are invertebrates belonging to the crustacean group, with high commercial value due to the distinctive flavor of their flesh and their nutritional value. Their consumption is attractive not only for their low caloric and lipid content but also for their high protein, vitamin, and antioxidant content. In addition to being marketed as food, shrimp can also be kept in aquariums as ornamental species or used to control and eliminate algae and some parasites in fish farms.

[0006] Due to their commercial potential, the cultivation of these animals in aquatic environments has become more technical over time to replicate their natural growth conditions and thus achieve greater and better production.

[0007] Shrimp are raised, from their larval stage, in ponds or pools usually located near the coast, rivers, or freshwater bodies. There, they undergo a fattening and growth phase based on different feeding intervals. Once they reach marketable size, the shrimp are harvested, collected, and frozen for transport to processing plants. Harvested shrimp must be handled quickly and efficiently to be frozen while still alive so that their quality does not deteriorate. To achieve this, once removed from the pond, the product is weighed and then transferred to containers with sufficient ice to maintain it at a temperature below 5°C while it is transported to the processing plant for grading and sorting.

[0008] The quality of shrimp upon arrival at the processing plant depends on the care and precautions taken during harvesting. Poor handling of shrimp, for example, during weighing of the harvested batch, can seriously affect their composition and cause significant production losses.

[0009] Shrimp harvesting can be done manually by collecting the animals directly with nets or mesh nets. Specifically, an open U-shaped mesh net is placed in front of the exit gate of the grow-out pond, where the shrimp are intercepted by a person with a cage (colloquially known as a bagman). The cages with live shrimp are removed by the bagman and then moved by a chain of personnel up the pool wall. There, the bagmen place the shrimp in treatment tanks with water, ice, and sodium metabisulfite. This compound acts as a preservative to prevent shrimp melanosis, the darkening and degradation of tissue caused by enzymatic reactions.

[0010] In these vats, the shrimp undergo a heat treatment and preservation process for a period of 5 to 10 minutes. The shrimp are then removed from the containers placed along rails approximately 6 to 8 meters long to drain and eliminate excess water. At the end of the rails is a floor or platform scale, where the containers move horizontally along a rail. Each container containing the shrimp is then positioned on the scale to obtain its corresponding weight. This weighing stage is very important because it allows for the precise determination of the quantity of shrimp collected and contributes to quality control during the harvesting process.

[0011] During this weighing, it is necessary to verify that each shrimp crate weighs approximately 50 pounds. If not, shrimp can be added or removed from each crate to meet this parameter. This weight limit serves as a measurement standard to determine the number of crates needed to meet the weight of each transported batch. Once the weight is recorded, each crate is transported (for example, by people forming a transport chain) to bins, or igloo-type containers or coolers with a capacity of 1,000 liters, which are placed on transport trucks. Once approximately 900 to 1,200 pounds of shrimp are deposited (containing between 18 and 24 crates), the bins are closed. Each truck can carry between 6 and 10 bins. The process of harvesting and loading the bins onto the trucks is repeated until the entire shrimp pond is harvested.

[0012] The modernization of the previous harvesting and weighing process has focused on collecting and transporting the shrimp using machinery to the thermal processing vats prior to weighing. Harvesting machines collect the shrimp using centrifugal pumps and hoses and deposit them in a hopper at the top of the harvester. In the hopper, the shrimp are separated from the water by a grate, which facilitates drainage of the water from the machine and transports the shrimp to the hopper outlet, where they are discharged into the treatment vats via a hose. From this point, the processing of the harvested shrimp is similar to the manual harvesting process, where they are weighed and deposited in the bins using collection drawers.

[0013] The prior art also discloses devices and processes for the technical implementation of the collection and harvesting (including the weighing stage) of related aquaculture products. For example, document CN204415809 / 31 describes an automatic packaging system for aquatic products comprising a conveyor, a detection device, a measuring hopper, a weighing device, a water addition device, a device for adding aquatic products, a feeding device, and a control device, where the conveyor is used to transport a packaging box.Meanwhile, the detection device is used to detect the packing box, the measuring hopper is placed on the conveyor, the weighing device is used to measure the weight of the measuring hopper, the water adding device is used to add water to the measuring hopper, the aquatic product adding device is used to add aquatic products into the measuring hopper, the feeding device is used to add feed to the measuring hopper, and the control device is used to control the conveyor, the detection device, the measuring hopper, the weighing device, the water adding device, the aquatic product adding device and the feeding device.This automatic packaging system for aquatic products has the advantage that the weights of aquatic products, water, and feeder do not need to be weighed manually, thus saving significant labor and reducing operating costs.

[0014] More generally, and not specifically for aquaculture products, document W02020051103 discloses a system for measuring the average weight and uniformity of a sample, among other suitable properties. Such a system includes a scale for measuring the weight of an object or set of objects placed on a weighing surface, and a collection container, such as a strainer placed on the surface, that can receive and contain objects from a sample to be measured. Such a system includes a processor, shown as a computer, which is connected to the scale to receive its information. The computer is programmed to calculate, record, tabulate, and display the average weight and uniformity of the sample, based on the measurements from the scale.

[0015] There are also technologically advanced weighing devices in the prior art with potential applications in the shrimp production and harvesting industry. Thus, document WO2019068292 discloses a weighing device comprising a load cell detachment guard with the load to be measured applied directly to the load cell's upper spherical surface and locking members consisting of locking slots in the load cell that force the insertion of parts into the slots of the weighing installation structure. This weighing device is reportedly used in the equipment called "Industrial Shrimp Batch Scale" from the company Intech. This scale is equipped with an onboard weighing unit with seaway compensation and is specifically designed for the automatic weighing of sacks of shrimp.By adding an additional hopper, the batch scale can be combined with a 5 kg shrimp scale in the same unit. The same amount of shrimp is weighed each time, and the weight is recorded digitally.

[0016] It is clear that none of the developments in the aforementioned documents are specifically designed to adapt to harvesters used in shrimp farming or to record shrimp weights, times, and mass flow, transmit them wirelessly via satellite, cellular network, or the internet, and analyze them to improve the harvesting process in real time. In fact, these developments are used for weighing small shrimp volumes and are limited to harvesting processes where shrimp output speeds are slower, and the harvest cannot be weighed in real time.

[0017] It's also important to mention that none of these developments can be adapted to the manual shrimp harvesting process, which often generates losses in the industry due to operational inefficiency. For example, manually weighing harvested shrimp runs the risk of incorrect weight measurements, excessive use of personnel resources, and diminishes the quality of the harvested product. Furthermore, this process can lead to product losses and depends on the proper functioning of the labor and operation of the scales and / or weighing machines involved.

[0018] In response to these problems, the patent document "Device and process for continuous weighing of live shrimp" reveals a device and process for the automatic and continuous weighing of live shrimp. The device is characterized in that it comprises a support structure, a gate subsystem that allows the flow of harvested shrimp, a batch weighing subsystem of the harvested shrimp, and a discharge hopper that directs the output of the weighed shrimp from the weighing device. The weighing device disclosed by said document is designed to be coupled to any shrimp harvesting machine and its operation is through a batch process, controlled by a PLC according to the signals captured by load cells and inductive sensors, which allow collecting, processing, and transmitting weighing information in real time and on-site using wireless technology.

[0019] While this device addresses existing problems in the field of technology, some drawbacks remain that hinder its optimal performance. For example, it has been noted that the device's weighing drum can shift and unbalance the load cells, in addition to exposing them to impact loads that reduce their lifespan. Additionally, the device requires difficult calibration conditions, and failures can affect the combine's operation.

[0020] Given the above, it is clear that the current state of the art still requires the development of automated and adaptable equipment that complements the shrimp harvesting value chain, enabling the collection and analysis of harvesting information to optimize resources and make decisions regarding harvester operations.

[0021] GENERAL DESCRIPTION OF THE INVENTION

[0022] Taking into account the existing technical needs, the present invention reveals a device and process for weighing live shrimp, both for harvest and transfer animals.

[0023] The device is characterized by a main support structure, a secondary support structure, and a weighing box that opens and closes via a gate controlled by a four-bar mechanism. This four-bar mechanism comprises main and secondary links located on either side of the gate and actuated by pneumatic pistons.

[0024] Furthermore, the present invention also relates to a weighing process using the device of the invention. Generally, the process involves the following steps: (a) product input, (b) product weighing, and (c) product discharge.

[0025] In this sense, the device of the invention is characterized in that it has a stable weighing system, reduces the mechanical impact associated with the opening and closing of the gate, thus extending the useful life of the load cells, reduces the accumulation of product in the gate, in case of failure it does not affect the operation of the harvester, has a high raw harvest capacity and provides safer calibration conditions.

[0026] Brief description of the figures

[0027] Figure 1 shows a shrimp harvester including the weighing device of the invention.

[0028] Figure 2 shows the main support structure of the weighing device of the invention.

[0029] Figure 3 shows the secondary support structure of the weighing device of the invention.

[0030] Figure 4 is a perspective view of the weighing box of the device of the invention.

[0031] Figure 5 is a bottom perspective view of the weighing box of the device of the invention.

[0032] Figure 6 shows the supports of the weighing box of the device of the invention. Figure 7 shows the hatch of the weighing box of the device of the invention.

[0033] Figure 8 is a side view of the weigh box when the gate is closed.

[0034] Figure 9 is a side view of the weigh box when the hatch is open.

[0035] Figure 10 is a perspective view of the weigh box when the hatch is open.

[0036] Figure 11 shows a main link of the 4-bar mechanism of the device of the invention.

[0037] Figure 12 shows a secondary link of the 4-bar mechanism of the device of the invention.

[0038] Figure 13 shows the pneumatic pistons that operate the 4-bar mechanism of the device of the invention.

[0039] Figure 14 is an exploded view of the 4-bar mechanism of the weighing device of the invention.

[0040] Figure 15 shows the locking system of the weighing device of the invention.

[0041] Figure 16 shows an exploded view of the locking system.

[0042] Figure 17 shows a perspective view of the positioning of the load cells in the weighing device of the invention. Figure 18 shows a top view of the positioning of the load cells in the weighing device of the invention.

[0043] Figure 19 shows the positioning of the inductive sensor in the weighing device of the invention.

[0044] Figure 20 shows an isometric view of the weighing plates, where the standard weights are placed to carry out the calibration.

[0045] Figure 21 shows a bottom view of the weighing box.

[0046] Figure 22 shows the opening of the gate in the hopper of the harvester in the process of the invention.

[0047] Figure 23 shows the entry of the product into the weighing box in the process of the invention.

[0048] Figure 24 shows the product weighing stage in the process of the invention.

[0049] Figure 25 shows the product discharge stage in the process of the invention.

[0050] Figure 26 shows the weighing stage of the empty and at-rest weighing box in the process of the invention.

[0051] DETAILED DESCRIPTION OF THE INVENTION

[0052] Firstly, it is clarified that the terms in which this description has been written must be understood within the technical field of the invention, always in the broadest and non-limiting sense thereof. In accordance with Figure 1 , the present invention relates to a device for weighing live shrimp that is installed in a shrimp harvester. The weighing device (1) comprises:

[0053] (a) Main support structure (2)

[0054] Structure that supports all elements of the weighing device. This structure can be seen in Figure 2.

[0055] (b) Secondary support structure (3)

[0056] A structure that provides mobile support for the load. This structure can be seen in Figure 3.

[0057] (o) Weighing box or bench (4)

[0058] As shown in Figure 4, the weighing box consists of a polygonal prismatic box in which the product to be weighed is deposited. It has two openings: an upper one for receiving the product and a lower one for unloading it.

[0059] Its geometry corresponds to an asymmetrically beveled hopper that prevents the generation of dead spots and thus allows rapid unloading of the product.

[0060] The differential bevel simultaneously accommodates the swing gate at the rear of the weigh box and maximizes the box's capacity. The polygonal shape of the weigh box allows for up to 60% more capacity compared to a cylindrical weigh box.

[0061] As shown in Figure 5, the discharge opening frame includes a round rod element that prevents damage to the product from sharp edges of the weighing box and provides rigidity to the discharge opening, reducing wear and extending its service life.

[0062] (d) Weighbox supports (5) They join the weighbox to the structure, reducing the degrees of freedom and providing stability. They can be seen in Figure 6.

[0063] (e) Gate (6)

[0064] It is a tray that, using links, allows the weighing box to be closed and opened. It is located in the lower opening of the weighing box. It can be seen in Figure 7.

[0065] (f) 4-bar mechanism

[0066] It allows the gate to be operated and is made up of (i) two main links or cranks (7) (shown in figure 11), one on each side of the gate, which act as a driving arm and (ii) two secondary links (8) (shown in figure 12), one on each side of the gate, which act as a rocker, that is, they perform a back and forth movement.

[0067] The links' connections to the gate include wear horns (9) as shown in figure 14. The horns are round pieces of esparto or iron that are placed for protection around other elements.

[0068] This system is actuated by a pair of pneumatic pistons (10) that drive the main links and cause the gate to open. As shown in Figure 13, the pneumatic pistons are attached to a base that is bolted to the weighing box. These pistons allow for smooth opening and closing and a higher load carrying capacity. Additionally, this drive system is low cost, easy to assemble, easy to maintain, and highly reliable.

[0069] In this way, the main links transmit the moving force from the pneumatic pistons to the scale gate, and the secondary links perform the movement passively. The four-bar mechanism eliminates mechanical impact and provides cushioning to the system. In this regard, it is also important to note that the residual motion occurs in the horizontal plane, not the vertical plane, which extends the lifespan of the load cells by not exposing them to impacts on their measuring plane.

[0070] Thus, it is important to note that the mechanism generates a "circular" motion, but through a linear actuator (the pneumatic piston), which has an end-of-stroke damping chamber, allowing the piston to brake at the end of the movement.

[0071] Additionally, the conversion of the motion from linear to circular reduces the speed at the time of closing and opening due to the mechanical conversion of the motion itself. Similarly, the mechanism is designed to have a space between the gate and the weighing box (in one embodiment of the invention, this space is 5 mm), so there is no physical contact between the two components, which reduces wear and prevents impacts.

[0072] The above factors help reduce the impact of opening and closing the gate.

[0073] The 4-bar mechanism also features the ability to fully close the gate, ensuring that it adopts the same angle as the weighing box and thus achieves a maximum tilt angle, which is greater than the angle of repose of the product relative to the metal surface. This reduces the likelihood of product accumulation on the gate.

[0074] Additionally, it is characterized by the fact that the links rotate approximately 90 degrees, with the gate's closed position being where the maximum torque is exerted due to the force of the piston. This is because this position must withstand the pressure of the product attempting to open the gate.

[0075] In this way, the 4-bar mechanism ensures that the gate remains closed even with a 5% pressure loss due to, for example, leaks, seal wear, or compressor pressure loss.

[0076] This gate drive system also ensures maximum gate opening, preventing contact with other elements of the device. This maximum opening significantly reduces the amount of product that can stick to the gate.

[0077] An additional advantage of the gate is that when no external force acts on it (for example, in the case of loss of pneumatic pressure, a common failure due to the sensitivity of the compressor), the gate will open between 55% and 60% of its maximum opening. This is important because, in the event of a failure or inability of the weighing device, harvesting can continue without performing automatic weighing.

[0078] This ensures 100% harvester operability, even when the weighing device is not in operation.

[0079] (g) Locking system

[0080] As shown in figures 15 and 16, it is made up of contact plates (11) that lift the weight of the entire mobile system, and the locking cams (12) which are connected by a rigid rod (13) and are actuated by a pneumatic piston (14). At the junction of the cams (12), shaft guides (15) and separating horns (16) are used.

[0081] The piston forces the cams to rotate to change the distance between the contact plates and the cams. In the locked position, the cams make contact with the contact plates and the entire weighing box is lifted, so the load cells no longer detect weight.

[0082] (h) Load cells (17)

[0083] Transducer used to convert a force, usually weight, into an electrical signal that can be measured analogously or digitally.

[0084] The load cells are arranged so that the geometric center of the triangle formed by the three weighing points coincides with the center of gravity of the weighing mechanism. This positioning of the cells, which can be seen in Figures 17 and 18, facilitates their inspection, readjustment, maintenance, and replacement in case of damage.

[0085] (i) Inductive sensor (18)

[0086] This is a type of sensor used to detect ferrous materials. In this device, the measured element corresponds to the position of the link, with the gate being closed at the moment the sensor detects the element. Its positioning can be seen in Figure 19.

[0087] (j) Discharge hopper (19)

[0088] Allows you to direct the shrimp output from the weighing device.

[0089] The technical advantages of the described weighing device are as follows:

[0090] - More stable weighing system due to: o A structure with fewer degrees of freedom that reduces vibration o Change in weight and load cell distribution o Four-bar mechanism that reduces mechanical impact and extends the life of the load cells - Reduction in product accumulation in the gate

[0091] - In case of failure of the weighing device, the gate remains open and the operation of the combine is not affected.

[0092] - High raw harvest capacity and fast product discharge, due to the polygonal prismatic shape of the weighing box

[0093] - Reduction in product damage due to the presence of round rods in the discharge opening

[0094] - Safer calibration conditions, which prevent the operator from being exposed to moving mechanisms

[0095] In a particular embodiment of the invention, the device is coupled to a harvesting machine. In another particular embodiment of the invention, the device can also be used to weigh manually harvested shrimp. In this embodiment, the shrimp collected in drawers from the pond gate can be transported and deposited in an auxiliary hopper connected to the device of the invention.

[0096] In one embodiment of the invention, the operation of the device of the invention is controlled by a main board comprising a programmable logic controller (PLC), a weighing module, a communication module, an engine controller for engine on, off and monitoring, which includes sensors for engine temperature, engine oil pressure, hydraulic oil temperature, hydraulic oil working pressure, fuel level, hydraulic oil level, a battery and a touch HMI control screen.

[0097] In a preferred embodiment of the invention, the engine controller is replaced by an electronic board that can read sensors for engine temperature, engine pressure, hydraulic oil temperature, hydraulic oil pressure, fuel level, hydraulic oil level, and battery voltage. In this case, the PLC communication module is eliminated, and an analog sensor reading module is added, as well as an additional touch-sensitive HMI display. In a particular embodiment of the invention, the operation of the device of the invention is also controlled by a solenoid valve board and / or a communications board. The solenoid valve board comprises a pneumatic solenoid valve manifold, and the communications board comprises a communication module with a radio frequency antenna.

[0098] In a particular embodiment of the invention, the functioning and operation of the device of the invention when coupled to a harvester is implemented by computer, specifically by a programmable logic controller (PLC) comprised in a main control board. Said weighing process controlled by the PLC comprises the steps of: a) Turning on the harvesting machine; b) Turning on the combustion engine and filling the pressurized air tank and; c) Activating the shrimp harvesting process; d) Activating the unlocking system of the weighing device (1); e) Activating the weighing device (1) by means of the harvesting machine; f) Collecting the information of the weighed batch of shrimp; g) Recording and processing the weighing data on a small board computer; and h) Transferring the processed data to a cloud server to feed the database tables.

[0099] The shrimp weighing process implemented by PLC also comprises a step of activating the locking system of the weighing device (1) once the process of collecting weighing data and using the device of the invention ends.

[0100] In a particular embodiment of the invention, step e) of collecting information on the shrimp batch occurs after the stabilization step of the weighing device (1) and before the unloading step of the weighed batch of the weighing process described above. In a particular embodiment of the invention, the information collected in step e) of the process implemented by PLC includes, but is not limited to, variables or parameters of time, weight and weighing duration. In a preferred embodiment of the invention, the information collected in step e) of the process implemented by PLC comprises the time and date of the weighed batch, the weight of the batch, the duration of the weighing of the batch, and the flow of shrimp in the weighing device (1), among others.

[0101] In a particular embodiment of the invention, in step f) of recording and processing weighing data, a Raspberry Pi type computer is used (local level). In a particular embodiment of the invention, in step f) of recording and processing weighing data, said information is recorded in one or more tables in CSV or JSON format.

[0102] In a particular embodiment of the invention, the processed data from step g) is transferred wirelessly via satellite, a cellular network, or a Wi-Fi network within the shrimp farm via radio frequency. Furthermore, the Raspberry Pi computer may include the option of downloading the logs via a hotspot.

[0103] On the other hand, the invention relates to a process for weighing live shrimp that uses the weighing device of the invention and that comprises the following steps:

[0104] (a) Income of the product,

[0105] (b) Weighing the product and

[0106] (c) Downloading the product.

[0107] As shown in Figures 22 and 23, step (a) involves (i) opening the gate on the harvester hopper (red arrow), allowing the product to pass into the weighing box (yellow arrows). Once a predefined amount of product has accumulated, (ii) the hopper gate closes, cutting off the flow of product to the box. The predefined product quantity is configured from the weighing device's control screen.

[0108] Subsequently, and as shown in Figure 24, stage (b) involves stabilizing the product and recording its weight.

[0109] Finally, and as shown in figure 25, stage (c) involves (i) the opening of the lower cover of the weighing box by the action of a four-bar mechanism and two pneumatic cylinders (red arrow) which allows the product to be discharged by gravity into the output hopper of the weighing device, and (ii) the closing of the lower cover of the weighing box.

[0110] In one embodiment of the invention, as shown in Figure 26, the process also includes a step (d) in which the empty weighing box is weighed at rest. The weighing performed in this step allows the tare to be performed, thus initiating a new weighing process.

[0111] Although the invention has been disclosed in detail for illustrative purposes, it will be recognized that minor variations or modifications are within the scope of the present invention.

Claims

CLAIMS 1. A device for weighing live shrimp (1), both for harvest and transfer animals, characterized in that it comprises a main support structure (2), a secondary support structure (3) and a weighing box (4) with an inlet opening and an outlet opening, where the outlet opening has a gate (6) controlled by a four-bar mechanism.

2. The device for weighing live shrimp (1) according to claim 1, characterized in that the four-bar mechanism comprises main links (7), secondary links (8) and pneumatic pistons (10).

3. The device for weighing live shrimp (1) according to claim 2, characterized in that the four-bar mechanism additionally comprises wear horns (9).

4. The device for weighing live shrimp (1) according to claims 1 to 3, characterized in that the weighing box (4) has an upper opening for receiving the product and a lower opening for discharging the product.

5. The device for weighing live shrimp (1) according to claims 1 to 4, characterized in that the weighing box (4) is polygonal prismatic.

6. The device for weighing live shrimp (1) according to claims 4 and 5, characterized in that the frame of the discharge opening includes a round rod element.

7. The device for weighing live shrimp (1) according to claims 1 to 6, characterized in that the weighing box (4) is attached to the support structures (2,3) by means of supports (5).

8. The device for weighing live shrimp (1) according to claims 1 to 7, characterized in that it comprises a locking system.

9. The device for weighing live shrimp (1) according to claim 8, characterized in that the locking system includes contact plates (11), and locking cams (12) connected by a rigid rod (13) and actuated by a pneumatic piston (14).

10. The device for weighing live shrimp (1) according to claims 1 to 9, characterized in that it comprises load cells (17) and an inductive sensor (18).

11. The device for weighing live shrimp (1) according to claim 10, characterized in that the load cells (17) are distributed so that their geometric center coincides with the center of gravity of the weighing mechanism.

12. The device for weighing live shrimp (1) according to claims 1 to 11, characterized in that it comprises a discharge hopper (19).

13. A process for weighing live shrimp, both for harvest and transfer animals, characterized in that it comprises the stages of: (a) Allowing the shrimp to enter the device according to claims 1 to 12, (b) Weigh the shrimp in batches in the weighing box, (c) Unload the shrimp; and (d) Tare the empty weighing box at rest.

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