Powder negative pressure filling system, powder filling machine and working method

Abstract

This invention relates to the field of food packaging technology, and particularly to a powder negative pressure filling system, a powder filling machine, and a working method. The powder negative pressure filling system includes: a tank sealing structure and a filling head, which changes the pressure environment inside the tank to achieve switching between negative pressure filling and stopping filling; a height adjustment unit to change the insertion length of the filling head relative to the tank; a negative pressure unit to provide filling negative pressure inside the tank; and a first weighing unit, the obtained weight of which guides the vertical height control of the height adjustment unit. The maximum powder filling capacity is negatively correlated with the insertion length of the filling head relative to the tank. The powder filling machine includes the powder negative pressure filling system for coarse powder filling and a screw filling system for fine powder filling. This invention replaces the mechanical screw with a negative pressure filling mechanism and introduces a height-adjustable structural unit and weighing feedback to achieve filling without mechanical contact, avoiding mechanical damage to powder particles and maintaining high filling rate and accuracy.

Description

Technical Field

[0001] This invention relates to the field of food packaging technology, and in particular to a powder negative pressure filling system, a powder filling machine, and a working method. Background Technology

[0002] For precise filling of powder products, a two-stage screw system is typically used. This system utilizes a large-diameter screw for coarse filling to achieve a high filling rate, while simultaneously employing a small-diameter screw for fine filling to achieve high filling accuracy. Although this solution is technically mature and operates stably, its core drawback lies in the fact that, to achieve accurate metering, the screw and stirring mechanism must be immersed in the powder for an extended period of time. The continuous mechanical compression exerted on the material during this process severely damages the powder particle size. Summary of the Invention

[0003] This invention provides a powder negative pressure filling system, a powder filling machine, and a working method, which can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] The powder negative pressure filling system includes:

[0006] The tank sealing structure seals the open end of the tank to be filled with powder;

[0007] The filling head extends into the tank body through the sealing structure in a sealed manner. By supplying gas, it changes the pressure environment inside the tank to achieve the switching between negative pressure filling and stopping of powder feeding.

[0008] A height adjustment unit provides vertically adjustable support for the tank body and / or vertically adjustable fixation for the filling head to change the insertion length of the filling head relative to the tank body.

[0009] The negative pressure unit provides negative pressure to the tank through the filling head;

[0010] The first weighing unit is used to obtain the weight of the powder filling the tank, and the weight is used to guide the vertical height control of the height adjustment unit.

[0011] The maximum amount of powder filling is negatively correlated with the insertion length of the filling head relative to the can body.

[0012] Furthermore, the filling head includes a gas flow channel and a powder flow channel;

[0013] A gas passage is provided between the gas flow channel and the powder flow channel;

[0014] The negative pressure unit also provides a material-cutting negative pressure inside the filling head, and the material-cutting negative pressure generates suction on the powder in the powder flow channel through the gas penetration position.

[0015] Furthermore, the gas flow channel includes a first channel for forming the filling negative pressure inside the tank, and a second channel for forming the material interception negative pressure inside the filling head;

[0016] The gas passage is located between the second channel and the powder flow channel.

[0017] Furthermore, the height adjustment unit includes:

[0018] The tray provides a supporting surface for the tank.

[0019] An electric cylinder and a servo motor, wherein the servo motor serves as the power source for the electric cylinder, enabling the electric cylinder to output linear driving force to the tray;

[0020] The weight is used to guide the power output of the servo motor.

[0021] The working method of the powder negative pressure filling system as described above includes:

[0022] The height adjustment unit is activated, causing the tank to make sealed contact with the tank sealing structure, and the filling head extends into the tank by a set length relative to the tank.

[0023] Start the negative pressure unit until the filling negative pressure is reached in the tank, and the powder is filled into the tank from the filling head;

[0024] When the top of the powder reaches a set height relative to the filling head, the inside of the tank is connected to the outside atmosphere to stop feeding;

[0025] Reactivate the height adjustment unit to remove the filling head from the tank.

[0026] The weight of the powder filled into the tank by the filling head is obtained and compared with the weight set value. When the deviation of the comparison result exceeds the set threshold, the insertion length of the filling head relative to the tank is adjusted according to the deviation.

[0027] Further, obtaining the weight of the powder filled into the tank through the filling head includes:

[0028] The weights corresponding to the N most recently filled tanks are accumulated, where N is greater than or equal to 2;

[0029] The average of the N weights is used as the weight to be compared with the weight set value.

[0030] Furthermore, it also includes switching the negative pressure unit to provide a material-cutting negative pressure inside the filling head, so as to generate suction force on the powder in the powder flow channel through the gas connection position between the gas flow channel and the powder flow channel.

[0031] Powder filling machine, including:

[0032] The powder negative pressure filling system described above enables coarse powder filling;

[0033] The screw filling system enables precise powder filling to achieve the final target filling volume. The screw filling system includes:

[0034] The hopper holds the powder.

[0035] A stirring mechanism is provided to stir the powder within the hopper.

[0036] The screw mechanism determines the fine filling amount based on the filling result of the powder negative pressure filling system, determines the number of screw rotations based on the fine filling amount, and controls the screw to rotate the number of rotations to feed the material.

[0037] The second weighing unit is used to obtain the weight of the powder filled into the tank by the powder negative pressure filling system and the screw mechanism.

[0038] Furthermore, it includes several production channels that operate synchronously, the production channels including the powder negative pressure filling system and the screw filling system.

[0039] The working method of the powder filling machine as described above includes:

[0040] Obtain the filling results of the powder negative pressure filling system;

[0041] The fine filling amount is determined based on the final target filling amount and the filling result;

[0042] The number of screw rotations is determined based on the fine filling amount and screw parameters.

[0043] Determine whether the amount of powder in the hopper meets the requirements. If so, start the screw mechanism and control the screw to rotate the specified number of revolutions.

[0044] The weight of the powder filled into the tank by the powder negative pressure filling system and screw mechanism is obtained;

[0045] The filling effect of the powder is judged based on the weight.

[0046] The technical solution of this invention can achieve the following technical effects:

[0047] The powder negative pressure filling system of this invention replaces the mechanical screw with a negative pressure filling mechanism and introduces a height-adjustable structural unit and weighing feedback, realizing filling without mechanical contact, effectively avoiding mechanical damage to powder particles, while maintaining high filling rate and accuracy.

[0048] The powder filling machine achieves coarse powder filling through a powder negative pressure filling system and fine powder filling through a screw filling system. The screw filling system determines the fine filling amount based on the filling result of the powder negative pressure filling system, which is more accurate than filling with a fixed filling amount and can compensate for filling deviations from the powder negative pressure filling system in real time. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a framework diagram of the powder negative pressure filling system in Example 1, wherein the height adjustment unit serves as a lifting unit;

[0051] Figure 2 This is a frame diagram of a partial structure consisting of the filling head and the tank body in Example 1;

[0052] Figure 3 This is an optimized framework diagram of the local structure composed of the filling head and the tank body in Example 1;

[0053] Figure 4 This is a flowchart illustrating the working method of the powder negative pressure filling system in Example 2;

[0054] Figure 5 This is a flowchart illustrating the comparison of the average of five weights with a set weight value in Example 2.

[0055] Figure 6 This is a frame diagram of the powder filling machine in Example 3;

[0056] Figure 7 This is a framework diagram of the weighing system in Example 3;

[0057] Figure 8 This is an optimized framework diagram of the powder filling machine in Example 3, which includes two production channels;

[0058] Figure 9 This is a flowchart illustrating the working method of the powder filling machine in Example 4. Detailed Implementation

[0059] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0060] Example 1

[0061] The powder negative pressure filling system includes:

[0062] The tank sealing structure seals the open end of the tank to be filled with powder. The filling head extends into the tank, sealingly penetrating the sealing structure, and changes the pressure environment within the tank by supplying gas to switch between negative pressure filling and stopping the powder feeding. A height adjustment unit provides vertically adjustable support for the tank and / or vertically adjustable fixation for the filling head, thereby changing the insertion length of the filling head relative to the tank. Specifically, the methods for changing the insertion length that need to be protected in this invention include the following three. When implementing the negative pressure powder filling system of this invention, any of the following methods falls within the scope of protection of this invention:

[0063] The first type uses the height adjustment unit as a lifting unit to vertically support and raise the tank to a variable height, so that the tank moves relative to the filling head to the filling working position.

[0064] The second type uses the height adjustment unit as a lowering unit to lower the filling head at a vertically fixed but variable height, so that the filling head moves relative to the tank to the filling working position.

[0065] The third type is a height adjustment unit that performs the dual functions of a lifting unit and a lowering unit. It raises the tank with a variable vertical support and lowers the filling head with a variable vertical fixation, so that the tank and the filling head can move relative to each other to the filling position.

[0066] like Figure 1 As shown, this embodiment specifically uses a height adjustment unit as a lifting unit for detailed description.

[0067] The powder negative pressure filling system also includes:

[0068] The negative pressure unit provides negative pressure to the tank through the filling head, which enables the powder to be drawn in by the filling head. The first weighing unit is used to obtain the weight of the powder filled in the tank, and the weight is used to guide the vertical height control of the height adjustment unit. In this embodiment, the vertical height control of the lifting unit is specifically the vertical support height control. The maximum amount of powder filled is negatively correlated with the length of the filling head relative to the tank.

[0069] This embodiment provides a negative pressure powder filling system capable of filling powder products. This system can replace screw filling, and the replacement includes, but is not limited to: using the negative pressure powder filling system of this embodiment for coarse filling of powder products, in conjunction with a screw filling system for fine filling; or, directly using the negative pressure powder filling system to fill the final target amount of powder products. The above usage methods of the negative pressure powder filling system in this embodiment can be selected according to the actual scenario.

[0070] The powder negative pressure filling system in this embodiment replaces the mechanical screw with a negative pressure filling mechanism and introduces a height-adjustable structural unit and weighing feedback, realizing filling without mechanical contact, effectively avoiding mechanical damage to powder particles, while maintaining high filling rate and accuracy.

[0071] The powder negative pressure filling system uses a filling head and a negative pressure unit to draw in powder through the negative pressure established inside the tank, without any mechanical parts being immersed in the powder. During the filling process, the powder is only subjected to airflow, without physical compression or friction, thus completely eliminating the risk of mechanical damage. It is particularly suitable for fragile, heat-sensitive, or high-precision powders, ensuring particle integrity and improving product quality and consistency.

[0072] In this embodiment, the tank sealing structure is an annular structure with a central perforated structure for the filling head to pass through. For sealing between the tank sealing structure and the filling head, a relatively simple method is to create a seal at the contact point between the inner wall of the perforated structure and the outer wall of the filling head. Combined with the seal between the tank sealing structure and the tank body, this allows for a well-sealed space within the tank, thereby enabling precise achievement of the required filling negative pressure. Regarding the structural relationship between the tank sealing structure and the filling head, the following structural schemes can be selected, but these are merely examples and are not intended to limit the scope of protection of this invention:

[0073] The tank sealing structure and filling head are separate components, allowing for independent fixation of both.

[0074] In this embodiment, the tank sealing structure is fixed at the required height to seal the tank after it has been raised to position. To achieve a better sealing effect, an elastic structure can be installed between the tank sealing structure and the fixed structure, allowing the entire tank sealing structure to make elastic contact with the tank. Alternatively, an elastic structure can be installed inside the tank sealing structure, allowing a portion of the tank sealing structure to make elastic contact with the tank. Both methods can more effectively ensure a good seal. The filling head can also be fixed at the required height.

[0075] In the above-described split-type configuration, given that the height adjustment unit in this embodiment functions as a lifting unit, and both the tank sealing structure and the filling head are fixedly installed, the sealing contact between the tank sealing structure and the filling head can always be maintained. However, when the height adjustment unit functions as a lowering unit, it is also preferable to maintain the sealing contact between the tank sealing structure and the filling head by controlling the movement range of the filling head, i.e., maintaining the filling head in a through-hole state relative to the tank sealing structure, thereby avoiding damage to the sealing structure during frequent establishment of a sealing relationship. Of course, when the sealing method used does not cause the above-mentioned damage problems, the movement range of the filling head can be more flexible.

[0076] The tank sealing structure and filling head are designed as a single unit, allowing them to be installed on the same foundation.

[0077] In this embodiment, when the base structure is fixed, both can be simultaneously fixed at the required height; and when the base structure moves relative to the tank, both can move relative to the tank simultaneously. Specifically, when the height adjustment unit performs the function of the lowering unit, the lowering unit can be fixedly connected to the base structure; as for whether the connection between the tank sealing structure and the filling head and the base structure is fixed or flexible, it is within the protection scope of this invention.

[0078] As a preferred embodiment, given that the tank type and related working parameters are determined, it is preferable to fix the filling head in place, thereby preventing the powder from falling unnecessarily due to vibration.

[0079] As a preferred embodiment of the above, such as Figure 2 As shown, the filling head includes a gas flow channel and a powder flow channel; a gas connection point is provided between the gas flow channel and the powder flow channel; the negative pressure unit also provides a material-cutting negative pressure inside the filling head, and the material-cutting negative pressure generates suction force on the powder in the powder flow channel through the gas connection point to stop the powder from falling from the filling head.

[0080] The gas flow channel allows gas inside the tank to flow outwards to gradually form the required filling negative pressure, a process that can be controlled by a filling negative pressure control valve; and it also allows external gas to flow into the tank to change the vacuum level in the negative pressure environment, achieving a state of connection with the atmosphere, a process that can be controlled by a vacuum breaking control valve; while the powder flow channel allows powder to be filled into the tank under negative pressure when the filling negative pressure meets the conditions, and stops feeding when the tank is connected to the atmosphere.

[0081] As a preferred embodiment of the above, the gas flow channel includes a first channel for creating a filling negative pressure inside the tank, and a second channel for creating a material-cutting negative pressure inside the filling head; the gas passage is located between the second channel and the powder flow channel. In this preferred embodiment, the negative pressure for feeding and material cutting off is provided through different channels, which allows the second channel providing the material-cutting negative pressure to be independently sealed, ensuring sufficient suction and achieving a better material-cutting effect inside the filling head; while the first channel allows gas flow through its open end relative to the inside of the tank.

[0082] To ensure accurate filling volume, it is preferable to continuously monitor the pressure value in the second channel during the material shut-off process. A stable pressure value is the key to ensuring the material shut-off effect. When the pressure fluctuates, it is necessary to determine whether there is a blockage at the gas passage and resolve it in a timely manner.

[0083] In this embodiment, with the tank weight known by default, the first weighing unit can indirectly obtain the weight of the powder filling the tank. Specifically, the weight obtained by weighing can be subtracted from the weight of the empty tank. In this way, the weight of the powder filling the tank is used as a guiding parameter for subsequent use. The weight of the empty tank can be selected as a quantitative value according to the type, or it can be obtained by weighing each tank one by one using an additional weighing unit, thereby accurately identifying the weight difference between different tanks and achieving more precise filling control.

[0084] In this invention, the maximum powder filling capacity is negatively correlated with the insertion length of the filling head relative to the tank. That is, the higher the outlet of the filling head is relative to the bottom of the tank, the higher the height of powder available for unblocked discharge, and thus the larger the set powder filling capacity can be. The specific working logic is as follows: The insertion length of the filling head relative to the tank is determined based on the set powder filling capacity. After insertion, filling is performed until the top of the powder reaches a set distance from the filling head. Weighing is then used to determine if the filling is up to standard. Based on the result, the insertion length of the filling head is dynamically adjusted. In this embodiment, this is achieved by adjusting the vertical support height of the lifting unit on the tank.

[0085] like Figure 3 As shown, in the above embodiments, the material cutting process can be achieved by controlling the material cutting negative pressure filling valve. In the above embodiments, the gas penetration point between the gas flow channel and the powder flow channel allows the material cutting negative pressure within the gas flow channel to generate suction on the powder through the gas penetration point, thereby preventing it from falling. During implementation, provided the above requirements are met, the distribution of the gas flow channel and the powder flow channel can be flexibly configured. For example, in use, they can be arranged horizontally side-by-side, or one can be arranged around the other; both are methods protected by this invention.

[0086] The mesh size for the pores at the gas penetration points can be determined based on the mesh size specifications of the powder. Specifically, a reference content can be set first. For the powder material in the direction from large to small mesh sizes, determine the mesh size specification range with the content as the reference content, and determine the lower limit of the mesh size specification range. The pore size specification is then set to 1.5 to 2.5 times the lower limit. For example, in the direction from large to small mesh sizes, if the reference content is 0.15%, the mesh size specification range is 300 mesh and above. Setting the pore size specification to 1.5 times 300 mesh would result in 450 mesh.

[0087] As a preferred embodiment of the above embodiments, a height adjustment unit is provided as a specific structural form of the lifting unit, the height adjustment unit comprising:

[0088] The tray provides a supporting surface for the tank; the electric cylinder and servo motor, with the servo motor serving as the power source for the electric cylinder, enabling the electric cylinder to output linear driving force to the tray; the weight guides the power output of the servo motor.

[0089] In this preferred embodiment, using the height adjustment unit as a lifting unit allows the filling head to switch between negative pressure filling and powder discharge in a stable state, avoiding the impact of mechanical vibration on the powder. In this optimized approach, the tray lifting height can be achieved by the PLC controlling the servo motor to drive the electric cylinder's lifting and lowering. The tank can be lifted to any height within its stroke range, and the servo system can provide real-time feedback on the lifting height, enabling real-time adjustments during operation. The amount of material discharged can be controlled by changing the PLC's parameter settings.

[0090] Example 2

[0091] This embodiment provides a method for operating the powder negative pressure filling system as described in Embodiment 1, including:

[0092] The height adjustment unit is activated to ensure that the tank body and the tank body sealing structure make sealed contact, and the filling head extends into the tank body by a set length.

[0093] Start the negative pressure unit until the tank reaches the filling negative pressure, and the powder will fill into the tank from the filling head.

[0094] When the top of the powder reaches the set distance value relative to the filling head, the inside of the tank is connected to the outside atmosphere to stop the feeding;

[0095] Reactivate the height adjustment unit to move the filling head out of the tank.

[0096] The weight of the powder filled into the tank by the filling head is obtained and compared with the weight setting value. When the deviation of the comparison result exceeds the set threshold, the insertion length of the filling head relative to the tank is adjusted according to the deviation.

[0097] like Figure 4 As shown, in this preferred embodiment, the height adjustment unit is also used as the lifting unit. By adjusting the vertical support height of the tank, the tank and the tank sealing structure are made to make sealed contact, and the filling head extends into the tank by a set length. Finally, given the weight of the tank, the weight of the powder filled into the tank by the filling head is obtained. When tanks arriving at the powder negative pressure filling system are filled on the production line, the above working method can realize real-time dynamic adjustment of the extension length, thereby ensuring the real-time accuracy of powder filling.

[0098] As a preferred embodiment, obtaining the weight of the powder filled into the tank by the filling head includes:

[0099] Accumulate the weights corresponding to the N most recently filled tanks, where N is greater than or equal to 2;

[0100] The average of N weights is used as the weight to compare with the set weight value.

[0101] like Figure 5 As shown, taking the cumulative net weight of the five most recently filled tanks as an example, the average value of the five net weights is compared with the set weight value. When the deviation between the average value and the set weight value is greater than the set value, the insertion length of the filling head relative to the tank is dynamically adjusted, thereby changing the filling volume of the subsequent tanks and realizing the autonomous correction of the filling amount.

[0102] By averaging multiple sets of data, the impact of abnormal fluctuations can be avoided, ensuring that the system remains in a stable control state.

[0103] As a preferred embodiment, the method further includes switching the negative pressure unit to provide a material-cutting negative pressure inside the filling head. This negative pressure, through the gas connection between the gas flow channel and the powder flow channel, generates suction on the powder within the powder flow channel, thereby preventing the powder from falling from the filling head. The material-cutting negative pressure is provided before the height adjustment unit is restarted. The technical effects achieved by this preferred solution are as described in Embodiment 1 above, and will not be repeated here.

[0104] During operation, the variance or standard deviation of the weights corresponding to the N tanks can be utilized. When the variance or standard deviation exceeds a set threshold, cleaning of the gas penetration points can be performed outside the tanks. This cleaning action can be carried out during the filling intervals of different tanks, thereby avoiding disruption to continuous production. Specifically, air can be blown into the gas penetration points through the gas flow channel to solve the blockage problem, thereby avoiding unstable negative pressure caused by local blockage and preventing different amounts of material from falling due to vibration during the operation of the height adjustment unit, which would affect the aforementioned weight. Of course, if cleaning cannot solve the problem, other measures must be adopted.

[0105] Example 3

[0106] Powder filling machines include:

[0107] As described in Example 1, the powder negative pressure filling system achieves coarse powder filling; the screw filling system achieves fine powder filling to reach the final target filling amount. The purpose of setting up coarse and fine powder filling in this example is consistent with the purpose of using a two-stage screw system in the prior art, and will not be repeated here. The difference is that the powder negative pressure filling system is used for coarse powder filling in this example, which allows the vast majority of the powder to avoid mechanical extrusion and maintain the required particle size. Specifically, in this example, the powder negative pressure filling system achieves 90-95% net content filling, and the screw filling system is used for supplementary filling to achieve high-precision filling of the remaining 5-10% net content. This ratio can be adjusted according to actual production needs.

[0108] In this embodiment, the screw filling system includes:

[0109] The hopper holds the powder; the mixing mechanism mixes the powder within the hopper; the screw mechanism determines the fine filling amount based on the filling result of the powder negative pressure filling system, determines the number of screw rotations based on the fine filling amount, and controls the number of screw rotations to discharge the powder through the screw portion submerged in the powder; the second weighing unit obtains the weight of the powder filled in the tank by the powder negative pressure filling system and the screw mechanism, and the weight is used to judge the powder filling effect.

[0110] like Figure 6 As shown, the powder filling machine in this embodiment is illustrated. In this embodiment, it is necessary to ensure that the screw part in the feeding position is submerged in powder so that the filling amount per rotation of the screw is stable and to avoid filling errors caused by dry running.

[0111] In this embodiment, the filling amount is determined based on the filling result of the powder negative pressure filling system, which is more accurate than filling with a fixed amount. It can compensate for the filling deviation from the powder negative pressure filling system in real time. After compensation, the weight of the powder filled into the tank by the powder negative pressure filling system and screw mechanism is obtained, which can accurately judge the powder filling effect.

[0112] Similar to Embodiment 1, in this embodiment, with the tank weight known by default, the second weighing unit can indirectly obtain the weight of the powder filled into the tank by the powder negative pressure filling system and the screw filling system. This weight is the sum of the weights of the two fillings, which can be obtained by subtracting the weight of the empty tank from the weight obtained by weighing. In this way, the tank weight can be selected as a quantitative value according to the type, or it can be obtained by weighing each tank one by one using an additional weighing unit, thereby accurately identifying the weight differences between different tanks.

[0113] like Figure 7As shown, this embodiment provides a complete weighing system implementation. The weighing system includes a first weighing unit and a second weighing unit as described in Embodiment 1 and Embodiment 3, respectively, and also includes a third weighing unit, wherein the third weighing unit is used to weigh and obtain the empty weight of the tank.

[0114] In this embodiment, the third weighing unit, the first weighing unit, and the second weighing unit are arranged sequentially. The first weighing unit is used to obtain the net weight of the powder after passing through the negative pressure filling system, and the second weighing unit is used to obtain the total net weight of the powder after passing through the negative pressure filling system and the screw filling system, i.e., the final net weight. The initial net weight is used to guide the vertical height control of the height adjustment unit, and the final net weight is used to judge the powder filling effect. The empty tank weight is used to accurately obtain the net weight of each different tank, avoiding deviations in the actual net content caused by differences in the empty tank weight, ensuring that each tank meets the equipment filling accuracy standard. The specific weighing can be achieved through a weighing sensor, which is existing technology and will not be described in detail here. Through the above three weighings, even when the material density changes, the goal of accurate net content can be achieved.

[0115] As a preferred embodiment of the above, the powder filling machine includes several production channels that operate synchronously, and the production channels include a powder negative pressure filling system and a screw filling system.

[0116] Taking a single production channel meeting the low-speed N tanks / min requirement as an example, two production channels can meet the medium-speed 2N tanks / min requirement, and three production channels can meet the high-speed 3N tanks / min requirement. During implementation, the parallel operation of multiple production channels can reduce some production costs, including but not limited to the power costs of the tank conveying device, the construction costs of the negative pressure system, the power costs of the height adjustment unit, and the power costs of the screw rotation, etc. Figure 8 As shown, an exemplary embodiment of a powder filling machine including two production channels is illustrated.

[0117] Example 4

[0118] The working method of the powder filling machine as described in Example 3, such as Figure 9 As shown, it includes:

[0119] Obtain the filling result of the powder negative pressure filling system; in this embodiment, the filling result is the weight of the powder filled into the tank through the filling head, i.e., the net filling weight, as an example;

[0120] The fine filling volume is determined based on the final target filling volume and the filling result;

[0121] The number of screw rotations is determined based on the fine filling amount and screw parameters;

[0122] Determine if the amount of powder in the hopper meets the requirements. If yes, start the screw mechanism and control the number of screw rotations. If not, replenish the powder.

[0123] The weight of the powder filled into the tank by the powder negative pressure filling system and screw mechanism is obtained;

[0124] The filling effect of the powder can be judged by its weight, and the degree of deviation can be used to determine whether it needs to be removed from the unqualified platform.

[0125] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A powder negative pressure filling system, characterized in that, include: The tank includes a sealing structure to seal the open end of the tank to be filled with powder; a filling head that extends into the tank through the sealing structure and changes the pressure environment inside the tank by supplying gas to switch between negative pressure filling and stopping the filling of powder; a height adjustment unit that provides vertically variable support for the tank and / or vertically variable fixation of the filling head to change the insertion length of the filling head relative to the tank; a negative pressure unit that provides negative pressure to the tank through the filling head; and a first weighing unit for obtaining the weight of the powder filled in the tank, the weight being used to guide the vertical height control of the height adjustment unit; wherein the maximum amount of powder filled is negatively correlated with the insertion length of the filling head relative to the tank.

2. The powder negative pressure filling system according to claim 1, characterized in that, The filling head includes a gas flow channel and a powder flow channel; a gas connection point is provided between the gas flow channel and the powder flow channel; the negative pressure unit also provides a material-cutting negative pressure inside the filling head, and the material-cutting negative pressure generates suction force on the powder in the powder flow channel through the gas connection point.

3. The powder negative pressure filling system according to claim 2, characterized in that, The gas flow channel includes a first channel for forming the filling negative pressure inside the tank, and a second channel for forming the material interception negative pressure inside the filling head; the gas passage position is located between the second channel and the powder flow channel.

4. The powder negative pressure filling system according to claim 1, characterized in that, The height adjustment unit includes: a tray providing a support surface for the tank; an electric cylinder and a servo motor, wherein the servo motor serves as the power source for the electric cylinder, enabling the electric cylinder to output linear driving force to the tray; and the weight is used to guide the power output of the servo motor.

5. The working method of the powder negative pressure filling system as described in any one of claims 1 to 4, characterized in that, include: The height adjustment unit is activated, causing the tank to make sealed contact with the tank sealing structure, and the filling head extends into the tank by a set length relative to the tank. The negative pressure unit is activated until the filling negative pressure is reached inside the tank, and powder is filled into the tank from the filling head. When the top of the powder reaches a set height value relative to the filling head, the inside of the tank is connected to the outside atmosphere to stop feeding. The height adjustment unit is activated again to move the filling head out of the tank. The weight of the powder filled into the tank by the filling head is obtained and compared with the weight set value. When the deviation of the comparison result exceeds a set threshold, the insertion length of the filling head relative to the tank is adjusted according to the deviation.

6. The working method of the powder negative pressure filling system according to claim 5, characterized in that, Obtaining the weight of the powder filled into the can by the filling head includes: accumulating the weights corresponding to the N most recently filled cans, where N is greater than or equal to 2; and using the average of the N weights as the weight to be compared with the weight set value.

7. The working method of the powder negative pressure filling system according to claim 2, characterized in that, It also includes switching the negative pressure unit to provide a material-cutting negative pressure inside the filling head, so as to generate suction force on the powder in the powder flow channel through the gas connection position between the gas flow channel and the powder flow channel.

8. A powder filling machine, characterized in that, include: The powder negative pressure filling system as described in any one of claims 1 to 4 enables coarse powder filling; A screw filling system enables precise filling of powder to achieve the final target filling amount. The screw filling system includes: a hopper for containing the powder; a stirring mechanism for stirring the powder in the hopper; a screw mechanism for determining the precise filling amount based on the filling result of the powder negative pressure filling system, determining the number of screw rotations based on the precise filling amount, and controlling the screw to rotate the specified number of rotations to discharge the powder; and a second weighing unit for obtaining the weight of the powder filled into the tank by the powder negative pressure filling system and the screw mechanism.

9. The powder filling machine according to claim 8, characterized in that, It includes several production channels that operate synchronously, and the production channels include the powder negative pressure filling system and the screw filling system.

10. The working method of the powder filling machine as described in claim 8, characterized in that, include: Obtain the filling results of the powder negative pressure filling system; The fine filling amount is determined based on the final target filling amount and the filling result; Based on the precise filling amount and screw parameters, determine the number of screw rotations; determine whether the amount of powder in the hopper meets the requirements; if so, start the screw mechanism and control the screw to rotate the specified number of times; obtain the weight of the powder filled into the tank by the powder negative pressure filling system and screw mechanism; determine the powder filling effect based on the weight.

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