A dispensing piston for a sterile powder dispensing machine

Abstract

The utility model provides a kind of sterile powder subpackaging machine's subpackaging piston, and the filter layer part of this packaging piston is composed of hollow shaft and sintered plate set at the suction port of one end of hollow shaft;Sintered plate is sintered from powder, and its inside has front and rear through micro-pore channel.The subpackaging piston of the utility model is mainly composed of two parts of hollow shaft and sintered plate, and sintered plate constitutes the filter layer part of piston, and the micro-pore channel in sintered plate is irregular and disorderly, and compared with traditional brush piston or woven mesh piston, its blocking drug powder effect is better, subpackaging precision is high, can work for a long time, and internal micropore will not be blocked by drug powder;And its structure is simple, manufacturing cost is low, occupies small space, and structure is compact.

Description

Technical Field

[0001] This utility model relates to a sterile powder dispensing machine, and more particularly to a dispensing piston for a sterile powder dispensing machine. Background Technology

[0002] The main function of a dispensing machine is to dispense solid powder into containers. Currently, there are roughly two types of dispensing machines on the market: screw dispensing machines, which rely on the spiral part of a rotating screw to push the powder into the container; and airflow dispensing machines, which use a vacuum to adsorb the powder into a metering chamber and then introduce compressed air to spray the powder into the container. Inside the metering chamber is a component that can both allow positive and negative pressure air to pass through and block the powder; this is generally called a piston. Both airflow tube-type and metering disc-type airflow dispensing machines use this piston.

[0003] In actual production, the physical properties of different batches of pharmaceutical powder vary significantly, such as bulk density, porosity, angle of repose, particle size distribution, and hygroscopicity. The suitability of the piston plays a crucial role in dispensing accuracy, necessitating the use of a suitable piston. One of the earliest pistons used employed stainless steel wire to bind a brush to a shaft, similar to a mop used for cleaning (e.g.,...). Figure 1 (As shown). Later improvements included making the end of the adjustable brush into a sleeve shape, with a bundle of stainless steel wires inside the sleeve. Through tension, the wires were automatically and evenly arranged tightly within the sleeve (as shown). Figure 2 (As shown). In addition, there is another type where two layers of stainless steel woven mesh are installed at the end of the hollow shaft, with the outer layer being fine mesh and the inner layer being coarse mesh.

[0004] Regardless of the piston's structural form, it must fulfill its most basic function: allowing both positive and negative pressure air to pass through while preventing powder from being sucked away or becoming clogged. Therefore, the manufacturing process and machining precision of the piston are crucial for ensuring dispensing accuracy. The early pistons mentioned earlier had excessively rough manufacturing processes and machining precision, which could lead to some powder being sucked away during the powder suction process, and prolonged operation could result in powder clogging the piston. Such substandard pistons pose a significant threat to ensuring dispensing accuracy and can no longer meet the increasingly stringent precision requirements of current aseptic preparations. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a dispensing piston for a sterile powder dispensing machine, which has the advantages of improving powder barrier stability and reducing the risk of channel blockage, in order to address the shortcomings of the existing technology.

[0006] To solve the above-mentioned technical problems, this utility model adopts the following technical solution:

[0007] A dispensing piston for a sterile powder dispensing machine, wherein the filter layer of the dispensing piston is composed of a hollow shaft and a sintered plate disposed at an air intake at one end of the hollow shaft; the sintered plate is formed by sintering powder and has micro-channels running through it.

[0008] Preferably, the hollow shaft is a hollow tubular structure, and its other end has an air outlet connected to a positive or negative pressure air device.

[0009] Preferably, the thickness of the hollow shaft tube is 1-5 cm.

[0010] Preferably, the hollow shaft is made of stainless steel or ceramic.

[0011] Preferably, the sintered plate is made of metal or ceramic material and has a thickness of 0.1-1 cm.

[0012] Preferably, the sintered plate is made by sintering metal powder or ceramic powder, and its porosity is 20-80%.

[0013] Preferably, a groove is formed on the inner peripheral wall of one end of the hollow shaft, and the sintered plate is interference-fitted into the groove.

[0014] Preferably, the bottom of the groove has a ring-shaped slot, and the slot is located near the outer end of the hollow shaft.

[0015] Preferably, the micro-channels on the sintering plate are arranged in a random and irregular manner, so that when a vacuum is introduced, only a very thin layer of powder is drawn in and blocked on the outside of the sintering plate.

[0016] Preferably, the outer periphery of the sintered plate is provided with a plurality of limiting protrusions that cooperate with the slot, and its inner edge is provided with rounded corners to facilitate embedding into the groove.

[0017] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0018] This invention relates to a dispensing piston for a sterile powder dispensing machine, mainly composed of a hollow shaft and a sintered plate. The sintered plate forms the filter layer of the piston. The micro-pores inside the sintered plate are disordered and irregular. When the piston is vented into a vacuum, only a very thin layer of powder is drawn in and blocked on the outside of the sintered plate. When compressed air is introduced, this powder layer is blown out. Compared with traditional brush pistons or woven mesh pistons, this dispensing piston has a better powder blocking effect, higher dispensing accuracy, can work for a long time, and will not be blocked by powder in the internal micropores. Moreover, it has a simple structure, low manufacturing cost, small footprint, and compact design. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the earliest type of adjustable brush piston.

[0020] Figure 2 A schematic diagram of the improved sleeve-type adjustable brush piston;

[0021] Figure 3 This is a schematic diagram of the overall structure of a dispensing piston for a sterile powder dispensing machine according to the present invention;

[0022] Figure 4 This is a schematic diagram of the assembly structure of a dispensing piston for a sterile powder dispensing machine according to the present invention.

[0023] The accompanying figures are labeled as follows:

[0024] 100-Hollow shaft, 101-Air outlet, 102-Air intake, 103-Groove, 104-Slot; 200-Sintered plate, 201-Micro-channel, 202-Limiting protrusion, 203-Rounded corner. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0026] Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0027] In existing technologies, the piston structure used in aseptic powder dispensing machines generally suffers from insufficient powder blocking effect and a high risk of internal blockage. For example... Figure 1 and Figure 2 As shown, traditional brush-type pistons form a filter layer using steel wire bundles, which are prone to powder leakage and pore deformation after prolonged use. While woven mesh pistons, with their double-layer metal mesh structure, can improve filtration, their complex assembly process increases maintenance costs. When dispensing highly hygroscopic or ultrafine particle powders, existing pistons struggle to balance airflow permeability with powder barrier properties, directly impacting dispensing accuracy and equipment stability.

[0028] To address these issues, researchers discovered that traditional filter structures suffer from uncontrollable pore distribution. Analysis of powder flow characteristics revealed that uniform, regular pores easily form powder accumulation paths, while irregular pores disrupt the directional migration of powder. Based on this, they attempted to fabricate the filter layer using a powder sintering process, utilizing the random accumulation of particles during sintering to form disordered channels. Further research showed that integrating the sintered plate with a hollow shaft simplifies the airflow path, enabling positive and negative pressure switching through a single filter interface and avoiding assembly errors associated with multi-layer structures.

[0029] Therefore, based on the above research and development concept, in some embodiments, such as Figure 3 As shown, this application proposes a dispensing piston for a sterile powder dispensing machine, the filter layer of which is composed of a hollow shaft 100 and a sintered plate 200. An air intake 102 is provided at one end of the hollow shaft 100, and the sintered plate 200 is fixed at the air intake 102. The sintered plate 100 is formed by a powder sintering process, resulting in irregular micro-channels 201 that extend from front to back.

[0030] The hollow shaft 100 refers to a hollow tubular structure, which can be fabricated from metal tubing. It is used to establish positive and negative pressure airflow channels and connect to external air source equipment. The wall thickness can be adjusted according to pressure requirements, for example, using stainless steel tubing with a thickness of 1-5cm, to reduce overall weight while ensuring structural strength.

[0031] Among them, sintered plate 200 refers to a porous filter element, which can be achieved by high-temperature sintering of metal or ceramic powder. During the sintering process, powder particles randomly accumulate to form disordered interconnected channels. For example, the porosity is controlled in the range of 40-60%, which can both ensure airflow and block the penetration of drug powder.

[0032] Specifically, when the dispensing piston is working, negative pressure airflow is transmitted to the sintering plate 200 through the hollow shaft 100. When the powder comes into contact with the outer surface of the sintering plate 200, the irregular micro-channels 201 allow only a single layer of powder to be adsorbed on the outer side of the sintering plate 100, forming a precise dosage control layer. After switching to positive pressure airflow, the adsorbed powder is completely blown away, avoiding dosage errors caused by residue. The disordered channels inside the sintering plate 200 break the traditional linear pore structure, eliminating the directional accumulation path of the powder in the channels and significantly reducing the risk of blockage.

[0033] Compared to existing technologies, traditional brush pistons rely on the gaps between steel wires to form a filter layer, with pore size limited by the density of the steel wire arrangement. In contrast, the sintered plate 200 used in this solution controls the pore size through powder particle size, allowing for precise adaptation to the characteristics of different powders. Compared to the dual-layer filter structure of existing woven mesh pistons, this solution uses a single sintered plate 200 to achieve gas-powder separation, reducing leakage points at the assembly interface and improving structural reliability.

[0034] Through the above technical solution, this application effectively prevents powder from entering the airflow channel, ensuring accurate dosage during dispensing. The disordered pore structure of the sintered plate 200 avoids the through-blockage of traditional straight pores, extending the maintenance cycle. The simplified overall structure reduces processing difficulty, and the integrated design of the hollow shaft 100 and the sintered plate 200 reduces the component volume and improves equipment space utilization.

[0035] In some of these embodiments, such as Figure 3 As shown, this application further proposes a hollow tubular structure within the hollow shaft 100, with an external positive and negative pressure air outlet 101 at its other end connected to a positive or negative pressure air device. The hollow tubular structure refers to a cylindrical component with a continuous internal channel, which can be made of stainless steel through precision casting or machining. The continuity of the internal channel ensures the continuous transmission of airflow. Connecting the external positive or negative pressure air device to the outlet refers to a sealed connection between the outlet and an external air source device via a standardized interface, specifically a quick-connect pneumatic joint or flange connection structure.

[0036] Specifically, the hollow tubular structure of the hollow shaft 100 forms a continuous airflow channel, and the air outlet 101 is located at the end of the tubular structure as an airflow passage interface. The positive and negative pressure air equipment forms a sealed connection with the air outlet 101 through standardized connectors. When the equipment is started, the positive pressure airflow is transmitted to the sintering plate 200 through this channel, while the negative pressure airflow is drawn in the opposite direction through the same channel.

[0037] In some embodiments, this application further proposes that the hollow shaft 100 is made of stainless steel or ceramic material, preferably 316L stainless steel; the tube thickness of the hollow shaft 100 is 1-5 cm, preferably 1-4 cm, and more preferably 1.5-2.5 cm. The tube thickness refers to the radial dimension of the tube wall of the hollow shaft 100. By limiting the tube thickness range, lightweight structure is achieved while ensuring reliability, and the reliability of powder blowing and suction is improved.

[0038] In some embodiments, this application further proposes that the sintered plate is made of metal or ceramic material, preferably 316L stainless steel, with a thickness of 0.1-1 cm. The thickness of 0.1-1 cm refers to the axial dimension range of the sintered plate 100, which can be achieved by adjusting the sintering process parameters. This thickness range can balance airflow efficiency and structural stability.

[0039] Furthermore, this application proposes that the sintered plate is made of metal powder or ceramic powder sintering, with a porosity of 20-80%, preferably 40-70%, and more preferably 45-60%. Here, "made of metal powder or ceramic powder sintering" refers to the process of melting and bonding metal or ceramic particles through a high-temperature sintering process to form a porous structure. Specifically, stainless steel powder, titanium alloy powder, or alumina ceramic powder can be used through a molding sintering process. Such materials possess corrosion resistance and mechanical strength, and can withstand the impact of high-pressure airflow in aseptic packaging environments. A porosity of 20-80% refers to the proportion of the volume of micropores inside the sintered plate to the total volume of the material. This range balances air permeability and barrier properties, allowing effective airflow transmission while limiting the penetration of drug powder through the pore size. The specific porosity is customized according to the powder characteristics.

[0040] In some of these embodiments, such as Figure 4 As shown, this application further proposes that a groove 103 be formed on the inner peripheral wall of one end of the hollow shaft 100, and a sintered plate 200 be interference-fitted into the groove 103. The groove 103 refers to an annular recessed structure machined on the inner peripheral wall of the hollow shaft 100. The width and depth of the groove 103 are designed to match the dimensions of the sintered plate 200, providing precise installation and positioning space for the sintered plate 200.

[0041] To improve the stability of the sintered plate 200 mounted on the hollow shaft 100, such as Figure 4 As shown, this application further proposes to provide a ring-shaped groove 104 at the bottom of the groove 103, with the groove 104 located near the outer end of the hollow shaft 100. The ring-shaped groove 104 refers to a continuous or discontinuous groove structure formed around the axis at the bottom of the groove 103, capable of circumferentially engaging with the limiting protrusion on the outer periphery of the sintered plate 200.

[0042] Specifically, after machining an annular groove 104 at the bottom of the groove 103, the spaced limiting protrusions 202 on the outer periphery of the sintered plate 200 can be embedded in the groove 104. When the sintered plate 200 is subjected to axial force, the annularly distributed groove 104 and the limiting protrusions 202 form multi-point contact, generating a uniform radial constraint force through mechanical interlocking. The layout of the groove 104 near the outer end of the hollow shaft 100 provides a clear axial positioning reference for the sintered plate 200 during installation, ensuring that the sintered plate 200 maintains a stable installation position during long-term use, thereby guaranteeing the continuity and precision stability of the assembly operation.

[0043] In some of these embodiments, such as Figure 4As shown, this application further proposes that the micro-channels 201 on the sintered plate 200 are arranged in a random and irregular manner. When a vacuum is introduced, only a very thin layer of powder is drawn in and blocked on the outside of the sintered plate. When compressed air is introduced, this layer of powder is blown out. The sintered plate 200 refers to a porous structure component formed by powder metallurgy, specifically using metal powder or ceramic powder sintered at high temperature, forming a disordered and interconnected pore network inside. The irregularly arranged micro-channels 201 refer to non-directionally arranged through-pores naturally formed during the sintering process, which can be achieved by controlling the powder particle size distribution and sintering temperature gradient. These channels exhibit random orientation and branching morphology in three-dimensional space.

[0044] Specifically, during the vacuum adsorption process, the airflow generates uneven flow resistance as it passes through the randomly distributed micro-channels 201 inside the sintering plate 200. This results in only a small amount of powder near the outer edge of the sintering plate 200 being adsorbed and forming a single-layer coating. When switching to compressed air, the shear force generated by the reverse airflow completely peels off the powder coating, preventing residues from accumulating within the micro-channels 201. This process limits the powder penetration depth through a physical barrier mechanism while simultaneously utilizing airflow dynamics to achieve a self-cleaning function.

[0045] In addition, such as Figure 4 As shown, this application further proposes that a plurality of limiting protrusions 202, which cooperate with the slots 104, be provided at intervals on the outer periphery of the sintering plate 200, and that the inner edge of the protrusions 202 be provided with rounded corners 203 to facilitate embedding into the grooves 103. The limiting protrusions 202 refer to protruding structures distributed along the outer periphery of the sintering plate 200, whose shape complements the annular slots 104 within the hollow shaft grooves 103, thereby limiting the axial displacement of the sintering plate 200 through mechanical interlocking. The rounded corners 203 refer to the arc-shaped transition structure on the inner edge of the sintering plate 200, which reduces pressing resistance by eliminating sharp edges on the assembly contact surface.

[0046] In some specific embodiments, the sintered plate 200 can be formed by sintering 316L stainless steel powder, with the powder particle size controlled in the range of 10-100 micrometers, the sintering temperature set at 1200-1350 degrees Celsius, and the holding time maintained at that temperature for 2-4 hours. After sintering, the porosity is controlled in the range of 40%-60%, and the average pore size is 5-50 micrometers. The edges of the sintered plate 200 can be machined with a rounded corner structure 203 to facilitate assembly with the groove 103 of the hollow shaft 100.

[0047] Combination Figure 3 and Figure 4As shown, the installation and working principle of the dispensing piston for the aseptic powder dispensing machine are as follows: First, the sintered plate 200 and the hollow shaft 100 are machined to predetermined dimensions. Then, the hollow shaft 100 is heated to a certain degree, and the sintered plate 200 is assembled into the groove 103 inside the hollow shaft 100. After cooling, a spinning process is required to firmly fix the sintered plate 200 in the groove 103 of the hollow shaft. In use, one side of the sintered plate 200 is in contact with the powder, and the other side is connected to positive and negative pressure air. When suctioning powder, negative pressure air is connected, and the powder is suctioned into the sintered side (in the metering chamber). When blowing powder, compressed air is connected, and the powder is blown into the container.

[0048] In summary, the piston structure composed of a hollow shaft 100 and a sintered plate 200 is simple, compact, and highly precise in machining. Its unique porous structure makes it suitable for most powder gas flow dispensing applications. Different powders require pistons with different sintered plate properties, and the thickness of the sintered plate 200, the size of the metal particles, the porosity, and the bubble point are all crucial parameters. In practical applications, it is often necessary to have several pistons with different performance indicators available for selection to meet varying dispensing requirements.

[0049] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0050] Secondly, the accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0051] Finally, the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A dispensing piston of a sterile powder dispensing machine, characterized in that, The filter layer of the dispensing piston consists of a hollow shaft (100) and a sintered plate (200) located at the air intake (102) at one end of the hollow shaft (100); the sintered plate (200) is made of powder sintering and has micro-channels (201) that run through it from front to back.

2. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The hollow shaft (100) is a hollow tubular structure, and its other end has an air outlet (101) connected to a positive and negative pressure air device.

3. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The thickness of the hollow shaft (100) is 1-5cm.

4. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The hollow shaft (100) is made of stainless steel or ceramic.

5. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The sintered plate (200) is made of metal or ceramic material and has a thickness of 0.1-1cm.

6. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The sintered plate (200) is made of metal powder or ceramic powder and has a porosity of 20-80%.

7. The dispensing piston of the aseptic powder dispensing machine according to claim 1, characterized in that, The hollow shaft (100) has a groove (103) on the inner peripheral wall at one end, and the sintered plate (200) is inserted into the groove (103) with an interference fit.

8. A dispensing piston for a sterile powder dispenser according to claim 7, characterized in that The groove (103) has a ring-shaped slot (104) at the bottom, and the slot (104) is close to the outer end of the hollow shaft (100).

9. A dispensing piston for aseptic powder dispensing machines according to claim 1, characterized in that, The micro-channels (201) on the sintered plate (200) are arranged in a disordered and irregular manner. When a vacuum is introduced, only a very thin layer of powder is drawn in and blocked on the outside of the sintered plate (200).

10. A dispensing piston for a sterile powder dispenser according to claim 9, characterized in that The outer periphery of the sintering plate (200) is provided with a number of limiting protrusions (202) that cooperate with the slot (104), and its inner edge is provided with rounded corners (203) to facilitate embedding into the groove (103).

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