Ultrasonic sealing systems and anvils
The anvil design in ultrasonic sealing systems addresses the challenge of non-uniform heating in packaging materials by optimizing pressure distribution through geometric profiles, ensuring uniform sealing and reducing power consumption.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TETRA LAVAL HOLDINGS & FINANCE SA
- Filing Date
- 2024-05-07
- Publication Date
- 2026-05-19
AI Technical Summary
Ultrasonic sealing systems face challenges in achieving uniform heating and sealing in both two-layer and three-layer regions of packaging material due to the nonlinear relationship between pressure and heating, exacerbated by the TS-LS cross, leading to potential defects and impact on food safety.
The design of an anvil with specific geometric shapes and profiles that balance heating between two-layer and three-layer regions by using ridges, support and release surfaces, and asymmetrical transitions to manage pressure distribution, ensuring uniform heating and sealing.
The anvil design achieves uniform heating and sealing, reduces the risk of overheating, and enhances sealing efficiency with less power consumption, while being adaptable to different packaging materials.
Smart Images
Figure 2026515762000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to packaging technology. More specifically, it relates to an ultrasonic sealing system, an anvil, and a method for transversely sealing a tube of packaging material using the ultrasonic sealing system.
Background Art
[0002] Ultrasonic sealing technology, also called ultrasonic welding technology, has long been widely used for sealing carton packages in the food packaging industry. Ultrasonic sealing is formed by generating ultrasonic vibrations in the sealing area to apply pressure and heat. This is usually achieved by sandwiching the packaging material between a vibrating transducer and an anvil. Heat is generated in the sealing area by the vibration, and the plastic of the packaging material melts. The applied pressure fuses the packaging material to form an airtight seal. The heat generated depends on the amount of pressure applied, the pressure distribution, and the amplitude of the vibration. Furthermore, it is necessary to control these factors in combination with parameters such as sealing time and sealing energy to achieve a desirable seal.
[0003] Ultrasonic sealing technology has the advantage that it does not require an electrically conductive material such as aluminum foil in the packaging material compared to induction sealing technology, also called induction heating technology. This improves the cost efficiency of the packaging material.
[0004] In a roll-fed packaging machine, ultrasonic sealing technology is usually used to form a transverse seal, that is, a weld at the bottom of the tube of the packaging material, thereby forming a package. The tube is formed by joining both ends of the web of the packaging material with a longitudinal seal. Due to the package design, an area where the transverse seal and the longitudinal seal intersect (sometimes called a TS-LS cross) occurs.
[0005] Because of the TS-LS cross, the sealing system used to form the lateral seal must be designed to handle both the areas with two layers of packaging material and the areas with three layers of packaging material (i.e., the TS-LS cross portion). This makes controlling the parameters of the sealing process difficult. As mentioned earlier, the pressure distribution itself is a fundamental element in the sealing process, and the amount of heat generated also depends directly on the pressure distribution. The fact that the vibration transducer and fixed anvil are made of rigid material makes the TS-LS cross a particularly challenging case. Furthermore, variations in the size and position of the longitudinal seal can affect the robustness of the sealing system, making the design even more difficult.
[0006] Defects in lateral seals can have a serious impact on the food safety of the package. Therefore, although solutions exist for processing TS-LS cloth in ultrasonic sealing devices, further improvements are needed. [Overview of the project] [Problems that the invention aims to solve]
[0007] The technology of this disclosure aims to mitigate, reduce, or eliminate, at least partially, the drawbacks and shortcomings of the above examples. In particular, it aims to provide improved ultrasonic sealing systems and anvils. Furthermore, the concept of the present invention also relates to packaging machines equipped with ultrasonic sealing systems and methods for operating ultrasonic sealing systems.
[0008] The inventors have realized a novel and improved method for ultrasonic sealing by utilizing the fact that the heating effect in packaging materials has a nonlinear relationship with pressure. Generally, the heating effect increases with sealing pressure, but this has been found to be effective only up to a certain pressure level. At higher pressures, the heating effect levels off or decreases. As part of the concept of the present invention, the nonlinear relationship between pressure and ultrasonic heating is utilized to balance heating between the two-layer and three-layer regions of the packaging material tube. By combining specific geometric shapes, sealing pressures, and ultrasonic amplitudes, it is possible to obtain uniform heating and uniform sealing results in both the two-layer and three-layer regions. [Means for solving the problem]
[0009] Various forms and embodiments of the disclosed invention are set forth below and in the attached independent and dependent claims.
[0010] According to a first embodiment, an anvil for an ultrasonic sealing system is provided for sealing a lateral seal portion of a tube of packaging material. The lateral seal portion comprises a first lateral edge portion, a longitudinal seal portion (LS), and a second lateral edge portion. The anvil includes a ridge extending along a first axis (A1) of the anvil, a release surface extending along the first axis of the anvil, and a support surface extending along the first axis of the anvil and positioned between the ridge and the release surface. The anvil further includes a first side portion, a second side portion, an intermediate portion, a first transition portion positioned between the first side portion and the intermediate portion, and a second transition portion positioned between the intermediate portion and the second side portion. In the first and second side portions, the ridge, the release surface, and the support surface conform to a first profile. In the intermediate portion, the ridge, the release surface, and the support surface conform to a second profile. The heights of the ridges and support surfaces in the first profile are higher than the corresponding heights in the second profile, and the height of the release surface in the first profile is the same as the height in the second profile.
[0011] The first and second lateral edges may be referred to as two-layer regions. The longitudinal sealing portion may be referred to as a three-layer region.
[0012] In this specification, the term “profile” in the first profile and the second profile means the shape and size (e.g., height and width) of the ridge, release surface and support surface as viewed in a cross section in the first axial direction, i.e., a cross section in a plane perpendicular to the first axis. The first profile may be considered as a profile adapted to a two-layer region, and the second profile may be considered as a profile adapted to a three-layer region.
[0013] To achieve more uniform heating in the two- and three-layer regions, relatively high pressure is required in the three-layer region. This can be achieved by using ridges. At the same time, the width of the ridges should be narrow, thereby limiting the required force and reducing the required ultrasonic output. This can result in high stress and high stress gradients in the three-layer region, potentially causing cracks in the packaging material. This negatively impacts sealing quality and package appearance. This effect can be mitigated by introducing support and release surfaces. In the design of the first and second profiles described above, different heights for the ridges and support surfaces can further advantageously achieve uniform pressure / heating distribution.
[0014] To further improve the seal balance between the two-layer and three-layer regions, it is necessary to avoid excessive heating in both regions while ensuring sufficient heating at the transition between them. To obtain a sufficient seal at the transition, it should be ensured that a sufficient minimum pressure exists at the transition at the start of the seal pulse. This is necessary to obtain heat at this transition throughout the entire seal pulse; otherwise, insufficient heat may occur, leading to a risk of leakage. Furthermore, the maximum pressure at the transition must not damage the packaging material, and a combination of high pressure and a steep pressure gradient is particularly dangerous.
[0015] Sufficient minimum and high pressure handling can be achieved by using relatively high pressure in the three-layer region (i.e., ridge 410) and limiting the pressure gradient using the support surface. Since the support surface follows the ridge (i.e., as the ridge increases / decreases from one profile to the other, the support surface increases / decreases accordingly), an increase in pressure also means an increase in support force. In this way, damage to the packaging material can be avoided.
[0016] In a longitudinal seal, the overlapping position and width of the packaging materials vary, but there are always sections that have a three-layer structure and sections that always have a two-layer structure. Therefore, the anvil 402 can be designed with two types of profiles: one optimized for the two-layer region and another optimized for the three-layer region.
[0017] In the first transition section, the support surface may transition from the fourth height of the first side to the sixth height of the intermediate section across the first width (W1) of the first transition section. In the second transition section, the support surface may transition from the sixth height of the intermediate section to the fourth height of the second side section across the second width (W2) of the second transition section. However, it should be noted that the widths of the first and second transition sections for ridge transitions may differ from those for support surface transitions.
[0018] In an alternative configuration of the first embodiment, an anvil for an ultrasonic sealing system for laterally sealing a tube of packaging material is provided. The anvil comprises a ridge extending along a first axis A1 of the anvil, a release surface extending along the first axis of the anvil, and a support surface extending along the first axis of the anvil and positioned between the ridge and the release surface, wherein the anvil comprises a middle section, a first side section, a second side section, a first transition section positioned between the first side section and the middle section, and a second transition section positioned between the middle section and the second side section, wherein in the first and second side sections, the ridge, release surface and support surface conform to a first profile, and in the middle section, the ridge, release surface and support surface conform to a second profile, wherein the heights of the ridge and support surface in the first profile are greater than the heights of the ridge and support surface in the second profile, and the height of the release surface in the first profile is the same as the height of the release surface in the second profile.
[0019] In the first transition section, the ridge and support surface may transition from the first height (H1) and second height (H2) of the first side section to the third height (H3) and fourth height (H4) of the intermediate section across the first width (W1) of the first transition section. In the second transition section, the ridge and support surface may transition from the third height (H3) and fourth height (H4) of the intermediate section to the fifth height (H5) and sixth height (H6) of the second side section across the second width (W2) of the second transition section. The first width (W1) of the first transition section may be smaller than the second width (W2) of the second transition section.
[0020] By making the first and second transition sections different widths, an asymmetrical transition from the first side through the intermediate section to the second side is achieved. This asymmetrical transition improves the heat / pressure distribution in the cross-section between the longitudinal seal and the transverse seal. In other words, more uniform heating can be achieved in the two-layer and three-layer regions. The longitudinal seal is asymmetrical by design due to the way the packaging materials overlap. The longitudinal seal is usually considered symmetrical in the transition from the two-layer to the three-layer. However, as the inventors have recognized, the formation of the transverse seal can be improved by considering that the longitudinal seal is actually asymmetrical (having one uncovered edge and one covered edge of the packaging material). Therefore, the asymmetrical shape of the anvil can be selected to compensate for the asymmetrical design of the longitudinal seal section. This allows for better handling of the molten plastic material of the packaging material, resulting in an improved transverse seal.
[0021] Furthermore, the asymmetrical transition provides a more robust anvil against variations in the tube's position.
[0022] Furthermore, the proposed anvil reduces the risk of overheating of the packaging material.
[0023] Furthermore, the proposed anvil enables more efficient use of sealing energy, thereby requiring less power and shortening sealing time.
[0024] The first height (H1) may be the same as the fifth height (H5). The second height (H2) may be the same as the sixth height (H6).
[0025] The intermediate portion may be positioned to interact with at least the LS portion of the tube in a lateral seal state. The first and second side portions may be positioned to interact with at least the first and second lateral edges of the tube in a lateral seal state.
[0026] The packaging material may comprise a cardboard layer and a plastic foil attached to the cardboard layer. The cardboard layer has the advantage of compressibility, and the plastic foil (also referred to herein as the plastic layer) can be melted by ultrasonic vibration to form a transverse seal. Thereby, the packaging material may not contain aluminum. When the transverse seal is formed by an induction heating-based sealing system, aluminum is generally used. By eliminating the aluminum layer, the packaging material becomes more cost-effective and more environmentally friendly.
[0027] The anvil may further comprise a recess disposed in the middle part and extending along the second axis A2 of the anvil. In the transverse seal state (i.e., during anvil operation), this recess may leave a trace on the transverse seal along the longitudinal direction of the package. This trace facilitates the quality control of the transverse seal by indicating the displacement of the tube relative to the anvil during the formation of the transverse seal.
[0028] The anvil may further comprise another recess extending along the first axis A1 for receiving a knife for cutting the tube.
[0029] The width of the first transition part, the width of the second transition part, and the width of the middle part can be set based on the width of the longitudinal seal part of the tube. In other words, the above widths may be selected based on the type of food packaging to be manufactured (e.g., packaging size and shape, thickness of the packaging material, etc.). The widths of the first and second transition parts and the middle part can be set such that sufficient energy is supplied to the first and second transverse edge parts and the longitudinal seal part.
[0030] According to a second embodiment, an ultrasonic sealing system is provided for sealing a lateral seal portion of a tube of packaging material. The lateral seal portion comprises a first lateral edge, a longitudinal seal portion (LS), and a second lateral edge. The ultrasonic sealing system includes an ultrasonic generator arranged to transmit ultrasonic vibrations to the lateral seal portion of the tube. The ultrasonic generator includes a sonotrode and a clamping unit. The ultrasonic sealing system further includes an anvil arranged opposite the ultrasonic generator. The anvil comprises a ridge extending along a first axis A1 of the anvil, a release surface extending along the first axis of the anvil, and a support surface extending along the first axis of the anvil and positioned between the ridge and the release surface. The anvil comprises a first side portion, a second side portion, an intermediate portion, a first transition portion positioned between the first side portion and the intermediate portion, and a second transition portion positioned between the intermediate portion and the second side portion. In the first and second side portions, the ridge, the release surface, and the support surface conform to a first profile. In the intermediate section, the ridges, release surfaces, and support surfaces follow the second profile. The heights of the ridges and support surfaces in the first profile are greater than the heights of the ridges and support surfaces in the second profile, and the height of the release surface in the first profile is the same as the height of the release surface in the second profile.
[0031] The sonotrode may be referred to herein as the active part of the ultrasonic generator. The clamp unit may be referred to as the stationary part of the ultrasonic generator. In the three-layer region, the pressure must be high enough to limit heating to the relevant area, while being low enough not to create a high stress gradient that would damage the packaging material. Separating the ultrasonic generator into an active part and a stationary part provides a way to manage these conflicting requirements. The active part provides ultrasonic heating in the three-layer region, while the stationary part can apply static pressure to the tube outside the lateral seal to reduce the heating effect on these parts. The stationary part engages with the support surface, providing an additional effect of preventing molten plastic from spreading from the lateral seal to the unsealed parts of the package.
[0032] It should be noted that the anvil in the second embodiment may be identical to the anvil in the first embodiment.
[0033] In another embodiment of the second aspect, an ultrasonic sealing system for sealing a tube of packaging material laterally is provided. The ultrasonic sealing system includes an ultrasonic generator arranged to transmit ultrasonic vibrations. The ultrasonic generator includes a sonotrode and a clamping unit. The ultrasonic sealing system further includes an anvil arranged opposite the ultrasonic generator. The anvil comprises a ridge extending along a first axis A1 of the anvil, a release surface extending along the first axis of the anvil, and a support surface extending along the first axis of the anvil and positioned between the ridge and the release surface. The anvil comprises a first side section, a second side section, an intermediate section, a first transition section positioned between the first side section and the intermediate section, and a second transition section positioned between the intermediate section and the second side section. In the first and second side sections, the ridge, the release surface and the support surface conform to a first profile. In the intermediate section, the ridge, the release surface and the support surface conform to a second profile. The heights of the ridges and support surfaces in the first profile are greater than the heights of the ridges and support surfaces in the second profile, and the height of the release surface in the first profile is the same as the height of the release surface in the second profile.
[0034] In the first transition section, the ridge and support surface may transition from the first height (H1) and second height (H2) of the first side section to the third height (H3) and fourth height (H4) of the intermediate section across the first width (W1) of the first transition section. In the second transition section, the ridge and support surface may transition from the third height (H3) and fourth height (H4) of the intermediate section to the fifth height (H5) and sixth height (H6) of the second side section across the second width (W2) of the second transition section. The first width (W1) of the first transition section may be smaller than the second width (W2) of the second transition section.
[0035] The ridge may be positioned to face the sonotrode of the ultrasonic generator. The support surface and release surface may be positioned to face the clamp unit of the ultrasonic generator. During operation, the support surface engages with the clamp unit, which can reduce the heating effect of the sonotrode in the tube area not to be sealed and prevent molten plastic from spreading into the package.
[0036] The surface of the sonotrode and the surface of the clamp unit positioned toward the anvil may lie on the same plane. In other words, the working and stationary parts may lie on the same plane. This simplifies the manufacturing of the ultrasonic generator. Furthermore, the same ultrasonic generator may be used for different applications (e.g., different packaging materials), and adaptation to different applications can be achieved by changing only the anvil.
[0037] The clamping unit may be spring-loaded. This has the effect of providing more independent forces between the active and stationary parts.
[0038] An elastic material may be provided on the support surface and / or the release surface and / or the surface of the clamp unit. Examples of elastic materials include polyurethane rubber or other suitable elastic materials. One effect of providing an elastic material on the surface of the clamp unit and / or the anvil that engages with the clamp unit is that the pressure applied by the clamp unit is more uniformly distributed.
[0039] The features of the first embodiment described above also apply to this second embodiment, where applicable. Please refer to the above to avoid unnecessary repetition.
[0040] According to a third embodiment, a packaging machine is provided, which includes a lateral sealing station (TS) for sealing and cutting tubes of packaging material laterally to form a package. The TS station includes an ultrasonic sealing system according to a second embodiment.
[0041] The features of the first and second embodiments described above also apply to this third embodiment, where applicable. Please refer to the above to avoid unnecessary repetition.
[0042] A fourth aspect provides a method for sealing a tube of packaging material laterally using an ultrasonic sealing system according to the second aspect. The packaging material includes a cardboard layer and plastic foil adhered to the cardboard layer. The method comprises providing a laterally sealed portion of the tube of packaging material between an ultrasonic generator and an anvil. The method further comprises generating ultrasonic vibrations using a sonotrode of the ultrasonic generator to at least partially melt the plastic foil of the packaging material in the laterally sealed portion. The method further comprises compressing the tube in the laterally sealed portion between the ultrasonic generator and the anvil, thereby creating pressure on the laterally sealed portion to bond the plastic foil and form a laterally sealed portion.
[0043] The features of the first, second, and third embodiments described above also apply to this fourth embodiment, where applicable. Please refer to the above to avoid unnecessary repetition.
[0044] Further scope of application of this disclosure will become apparent from the following detailed description. However, the detailed description and specific examples illustrate some variations of the concept of the present invention, and it will be apparent to those skilled in the art from the detailed description that various changes and modifications are possible within the scope of the concept of the present invention.
[0045] Therefore, it should be understood that the concepts of the present invention are not limited to the components described in the specific steps or systems of the described methods, and that the methods and systems may be modified. It should also be understood that the terms used herein are for the purpose of describing specific embodiments and are not intended to be restrictive. It should be noted that articles such as “a,” “an,” “the,” and “said” used herein and in the appended claims mean that there is one or more elements unless explicitly stated otherwise in the context. Therefore, for example, the expression “a device” or “the device” may include multiple devices. Furthermore, phrases such as “comprising,” “including,” and “containing” do not exclude other elements or steps.
[0046] The above and other aspects of the concept of the present invention will be described in more detail with reference to the accompanying drawings illustrating variations of the concept of the present invention. These drawings are not intended to limit the present invention to any particular variation, but rather to illustrate and illustrate the concept of the present invention.
[0047] As shown in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and are provided to illustrate the general structure of the modifications of the present invention. The same reference numerals refer to the same elements throughout. [Brief explanation of the drawing]
[0048] [Figure 1] This is a diagram showing a typical packaging machine. [Figure 2] This figure shows an example of a package after horizontal sealing. [Figure 3A] This is a diagram showing a tube of packaging material viewed from the side. [Figure 3B] This is a cross-sectional view of a packaging material tube, seen from above. [Figure 4A] This is a diagram showing an example of an ultrasonic sealing system. [Figure 4B] This figure shows an example of a part of an anvil. [Figure 5A] This figure shows an example of the first profile of an anvil. [Figure 5B] This figure shows an example of the second profile of the anvil. [Figure 5C] This figure shows an example of an anvil sweep profile. [Figure 5D] This figure shows further examples of anvil sweep profiles. [Figure 6A] This figure shows different positions of the longitudinal seal portion relative to a part of the anvil. [Figure 6B] This figure shows different positions of the longitudinal seal portion relative to a part of the anvil. [Figure 6C] This figure shows different positions of the longitudinal seal portion relative to a part of the anvil. [Figure 7] This is a perspective view showing an example of an anvil. [Figure 8] This flowchart shows a method for sealing a tube of packaging material laterally. [Modes for carrying out the invention]
[0049] The concept of the present invention will be described in more detail below with reference to the accompanying drawings. However, although several modifications are shown, the concept of the present invention may be carried out in many different forms and is not limited to the modifications disclosed herein. These modifications are provided for completeness and comprehensively illustrate the scope of the concept of the present invention to those skilled in the art.
[0050] Furthermore, it should be understood that the terms used herein are used solely for the purpose of describing specific embodiments and are not intended to be restrictive. In this specification and the appended claims, articles such as “a,” “an,” “the,” and “said” should be interpreted as meaning that there is one or more elements, unless the context clearly indicates otherwise. For example, the expression “unit” or “the unit” may, depending on the context, refer to one or more units. In addition, the terms “comprise,” “include,” and “contain” do not preclude other elements or steps. In this specification, the terms “comprise” or “comprising” are interpreted as identifying the presence of the described feature, element, step, or component. These do not preclude the presence or addition of one or more other features, elements, steps, components, or groups thereof. The terms “and / or” are interpreted as meaning “both” or “each as an alternative.”
[0051] Furthermore, while terms such as "first," "second," etc., may be used in this specification to describe various elements or features, it should be understood that these elements are not limited by these terms. These terms are merely used to distinguish one element from another. For example, the first side may be referred to as the second side, and similarly, the second side may be referred to as the first side. These do not depart from the scope of this embodiment. The first side and the second side are both sides, but they are not the same side.
[0052] An anvil for an ultrasonic sealing system, an ultrasonic sealing system including an anvil, a filling machine including an ultrasonic sealing system, and a method for sealing a tube of packaging material laterally using an ultrasonic sealing system will be described with reference to Figures 1 to 8.
[0053] Figure 1 is a schematic diagram of the packaging machine 100. In its broadest form, the packaging machine 100 includes a lateral sealing station 114 that seals and cuts a tube 112 of packaging material laterally to obtain a package 116. The packaging material may consist of a cardboard layer and plastic foil, the plastic foil of which may be attached to the cardboard layer. The lateral sealing station includes an ultrasonic sealing system 200, which will be described later in relation to Figures 2 and 4A to 7. The packaging machine 100 may be a standalone packaging machine or may be part of a larger food packaging or processing line.
[0054] In the example shown in Figure 1, the packaging machine 100 is a roll-feed packaging machine, the general principle of which will be described later. In such a machine, the packaging material is supplied on a roll (or reel) 102 of the packaging material and loaded into the reel receiving section 106 of the packaging machine 100. From the roll 102 of the packaging material, a web 104 of the packaging material is formed. Although not shown, the web 104 of the packaging material may pass through a sterilization station 106 to remove or reduce unwanted microorganisms from the web 104. Sterilization may be carried out using, for example, a hydrogen peroxide bath, a low-voltage electron beam (LVEB) device, or other suitable device that meets food safety regulations.
[0055] After sterilization, the web 104 is formed into a tube 112, for example, by a longitudinal sealing station 110. The tube 112 is formed by joining the two ends of the web 104 by longitudinal sealing. In this specification, “longitudinal direction” refers to the longitudinal direction of the web 104 or tube 112 of the packaging material. Therefore, the longitudinal direction coincides with the supply direction FD in the packaging machine 100. After the tube 112 is formed, food FP can be supplied into the tube 112 via a product filling pipe 108, of which at least a portion is located inside the tube 112.
[0056] The filled tube 112 reaches a lateral sealing station 114 equipped with an ultrasonic sealing system 200. Here, "lateral" refers to the lateral direction (i.e., lateral TD) of the tube flattened at the lateral sealing station 114. At the lateral sealing station 114, a lateral seal (TS) is applied to the lower end of the tube 112 using the ultrasonic sealing system 200. Generally, the ultrasonic sealing system 200 (described later in relation to Figure 2) has two main functions: 1) to provide a lateral seal, i.e., to weld two opposing aspects of the tube 112 together, separating the product at the bottom of the tube 112 positioned below the ultrasonic sealing system 200 from the product inside the tube 112 positioned above the ultrasonic sealing system 200; and 2) to cut the bottom of the tube to form a package 116. Alternatively, instead of performing the lateral sealing and bottom cutting in the same system 300 as shown in the figure, the bottom cutting step may be performed in a subsequent process using a separate device, or, if the package is sold in multi-packs, may be performed by the consumer.
[0057] After the package 116 is formed, it can be folded in a folding station (not shown) to form the finished food package 116.
[0058] Figure 2 is a cross-sectional view of the ultrasonic sealing system 200. More specifically, Figure 2 illustrates in detail the general principle and process of the ultrasonic sealing system 200. The process of operating the ultrasonic sealing system 200 to form a lateral seal is further described below with reference to Figure 8.
[0059] The ultrasonic sealing system 200 is configured to seal the transverse seal portion 302 of the tube 112 of the packaging material. The transverse seal portion 302, further illustrated in relation to Figures 3A and 3B, includes a first transverse end 304, a longitudinal seal (LS) portion 306, and a second transverse end 308.
[0060] The ultrasonic sealing system 200 comprises an ultrasonic generator 400 and an anvil 402, which are described further below, for example, in reference to Figures 4A and 4B. The ultrasonic sealing system 200 may also comprise a plurality of pairs of ultrasonic generators 400 and anvils 402 arranged in a jaw system so as to form a lateral seal without interrupting the continuous movement of the tube 112.
[0061] The ultrasonic generator 400 is positioned to transmit ultrasonic vibrations to the lateral seal portion 302 of the tube 112. The anvil 402 is positioned opposite the ultrasonic generator 400 and provides a reaction force to the ultrasonic generator 400.
[0062] To further control the molding process of package 116, the ultrasonic sealing system 200 may further include a so-called volume-forming flap (not shown). More specifically, the volume-forming flap may be used to mold a tube 112 having a circular cross-section into a package having a rectangular cross-section in a controlled manner.
[0063] Moving on to the process of the ultrasonic sealing system 200, as shown in Figure 1, the tube 112 is preferably supplied from above so that the product is held inside the tube. In the first stage, sealing stage S, the ultrasonic generator 400 and the anvil 402 are moved toward each other in their respective opposite directions so that the two opposite sides of the tube 112 are pressed together. Either the ultrasonic generator or the anvil may be fixed, or only the other may be moved.
[0064] To achieve a lateral seal, ultrasonic vibrations are generated by the ultrasonic generator 400, supplying heat to the packaging material. This heat at least partially melts the plastic layer of the packaging material (also called plastic foil, polymer layer, or thermoplastic polymer layer), allowing the two opposing sides of the tube 112 to adhere to each other and maintain a single unit even after the applied pressure is removed. In a subsequent step (hereinafter referred to as cutting step C), the lower part 104 of the tube is cut off (for example, by a knife 208) to form the package 116. In this example, the knife 208 is located on the anvil 402. However, the knife 208 may be located on the opposite side of the tube 112, on the ultrasonic generator 400. Alternatively, the cutting step may be performed by a separate device located downstream of the ultrasonic sealing system 200.
[0065] To improve the package formation speed, parts of the ultrasonic sealing system (e.g., ultrasonic generator 400, anvil 402, and other optional components) can be moved along the supply direction FD with the tube 112 during the sealing stage S and the cutting stage C. Therefore, the ultrasonic generator 400 and anvil 402 shown in the sealed state S may be the same as the ultrasonic generator 400 and anvil 402 in the cutting state C.
[0066] Figure 3A is a side view of the packaging material tube 112, showing the stage in which it is being compressed to form a lateral seal portion TS. In this specification, "side view" refers to the case where the tube 112 is oriented vertically, as shown in Figure 2, for example. Figure 3B also shows the tube 112, but this is a cross-sectional view from above, for example, a cross-section along line E-E'. It should be noted that the sizes and proportions of the parts and regions shown here should be understood as examples that mainly illustrate different parts and regions of the tube 112 and do not necessarily represent the actual packaging material tube 112.
[0067] As shown in the figure, when the tube 112 is flattened, it can be divided in the lateral direction (TD) of the tube into a first lateral end 304 and a second lateral end 308. A longitudinal seal portion LS306 exists between the first lateral end 304 and the second lateral end 308. These portions may extend along the longitudinal direction of the tube 112. The first and second lateral ends 304 and 308 can be recognized as regions where the thickness of the tube 112 is two layers, i.e., two-layer regions of the tube 112.
[0068] The LS portion 306 can be defined as the portion of the tube 112 whose thickness is affected by the LS. In other words, the LS portion 306 may be considered as a three-layer region of the tube 112. In the sub-portion of the LS portion 306 (hereinafter referred to as the LS region 300), the tube 112 of the packaging material is compressed to a three-layer thickness by the folding of the packaging material to form the LS. The LS portion 306 further extends over the LS strip 314 and is defined by the LS strip region 316. The LS strip is applied during the formation of the LS and seals the inside of the tube 112. The presence of the LS strip and the folding of the packaging material also affect the thickness of the tube in the LS strip region 316 and must be taken into consideration when forming the TS.
[0069] In the longitudinal direction LD (perpendicular to TD), the TS portion 302 can be defined as the region where the TS is formed. The TS portion can be defined as the region located on both sides of the cutting line 312 where the tube 112 is cut to form two independent packages, as shown in the figure. It should be noted that if the TS is formed within the TS portion 302, it is not necessary to cover the entire TS portion 302. The TS portion 302 should be understood as a part involved in the TS formation process, for example, in the process of forming a lateral seal, in the sense that it may come into contact with the ultrasonic generator 400 and / or anvil 402.
[0070] A TS-LS cross 310 (or TS-LS overlapping region) is formed at the intersection of the TS section 302 and the LS section 306, and is shown by diagonal lines in the figure.
[0071] Figure 4A illustrates an ultrasonic sealing system 200 based on the concept of the present invention. In particular, Figure 4A shows the ultrasonic sealing system 200 in a first cross section along line B-B' (see Figure 4B) at a first position along the first axis (denoted A1) of the anvil 402, and in a second cross section (shown by diagonal lines) along line C-C' (see Figure 4B) at a second position along the first axis A1. Figure 4B shows a portion of the anvil 402 of the ultrasonic sealing system 200 in a cross section along line A-A' (see Figure 4A) at a position along the second axis (denoted A2) of the anvil 402. The first axis A1 and the second axis A2 are perpendicular to each other. During operation, the first axis A1 corresponds to the lateral direction of the tube 112, and the second axis A2 corresponds to the longitudinal direction (or feeding direction) of the tube 112.
[0072] The ultrasonic sealing system 200 shown herein is configured to form lateral seals on both sides of a cutting line separating two consecutive packages. Thus, the ultrasonic sealing system 200 may comprise a first portion 436a and a second portion 436b. The first portion 436a and the second portion 436b are configured to form a lateral seal on one of the two consecutive packages. The first portion 436a and the second portion 436b may be separated by a center line D-D' as shown. The center line D-D' may be an axis of symmetry. In other words, the first portion 436a and the second portion 436b may be symmetrical about the line D-D'. Thus, if, for example, the anvil 402 comprises a ridge 410, it should be understood that it may have another ridge on the opposite side of the center line D-D' as shown. However, as can be easily understood, the ultrasonic sealing system 200 may instead be configured to form only one lateral seal. That is, the first part 436a and the second part 436b can be separated into two separate elements. Thus, the anvil 402 may have only one ridge. In the following description of the ultrasonic sealing system 200, we will mainly refer to one part (here, the first part 436a), but similar features and embodiments also apply to the second part 436b.
[0073] The ultrasonic generator 400 is positioned to transmit ultrasonic vibrations to the lateral seal portion of the tube when in operation. This generates heat within the packaging material, resulting in at least partial melting of the plastic material in the lateral seal portion.
[0074] The ultrasonic generator 400 comprises a sonotrode 406 (also called a horn) and a clamp unit 408. The sonotrode 406 is configured to supply alternating pressure, thereby generating ultrasonic vibrations. The clamp unit 408 is configured to apply static pressure to the tube 112 during lateral seal formation. Thus, the sonotrode 406 and the clamp unit 408 are controllable separately. The clamp unit 408 may be spring-loaded to provide pressure more independent of the sonotrode 406. Alternatively, or in combination, the clamp unit 408, more specifically the surface 432 of the clamp unit 408, may be provided with an elastic material containing different types of elastomers such as polyurethane or silicone. This may result in more uniform static pressure. Alternatively, the elastic material may be provided on the support surface 412 and / or release surface 414 of the anvil 402 (described later). The surface 430 of the sonotrode 406 and the surface of the clamp unit 408 (both surfaces are positioned toward the anvil 402) may be coplanar. In other words, the surface of the ultrasonic generator 400, which is positioned to engage with the packaging material during the sealing process, may be coplanar.
[0075] The ultrasonic sealing system 200 further comprises an anvil 402. The anvil 402 is positioned opposite the ultrasonic generator 400. The anvil 402 comprises a ridge 410. The ridge 410 extends along a first direction A1 of the anvil 402. That is, the ridge 410 may extend along the first axis over the entire length of the anvil 402. The purpose of the ridge 410 is to concentrate pressure and ultrasonic heating in the area around the ridge 410. This is because the ridge 410 is the ridge of the anvil 402 that first contacts the ultrasonic generator 400. In particular, the ridge 410 is positioned to face or contact the sonotrode 406 of the ultrasonic generator 400. In other words, the ridge 410 is positioned where the working part of the ultrasonic generator 400 operates during the sealing process. The anvil 402 further comprises a release surface 414 extending along the first axis A1 of the anvil 402. The anvil 402 further comprises a support surface 412. The support surface 412 extends along the first axis A1 of the anvil 402 and is positioned between the ridge 410 and the release surface 414. Preferably, the support surface 412 has a lower height than the ridge 410. The release surface 414 has a lower height than the support surface 412. Preferably, the support surface 412 and the release surface 414 are positioned to face the clamp unit 408 of the ultrasonic generator 400.
[0076] The support surface 410 (integrated with the clamp unit 508) provides a constant static pressure capable of blocking ultrasonic motion or ultrasonic heating that occurs between the sonotrode 406 and the ridge 410. Thus, the support surface acts to confine the sealing process to a clearly defined area around the ridge 410, preventing the packaging material from being damaged by ultrasonic vibrations outside the active lateral sealing area. The support surface (integrated with the clamp unit 408) may have another advantage: it prevents molten plastic from leaking out of the seal and flowing into the package.
[0077] The release surface 414, located on the outside of the support surface (viewed from the center line D-D'), functions as a region where little or no pressure or contact with the packaging material occurs. Therefore, a seal may not be formed on a portion of the tube 112 located between the clamp unit 408 and the release surface 414 during the sealing process. Looking at the cross section A-A' in Figure 4B (i.e., the cross section of line A-A' along the first axis A1 of the anvil), the anvil 402 can be divided into several different parts. The anvil 402 comprises a first side section 420 and a second side section 428. The first side section 420 and the second side section 428 may be the outermost parts of the anvil 402 along the first direction A1. The first side section 420 and the second side section 428 are arranged to interact with the first transverse edge 304 and the second transverse edge 308 of the tube 112. In other words, the first and second side portions 420 and 428 may be the first and second two-layer regions of the anvil 402.
[0078] The anvil 402 further comprises an intermediate portion 424 positioned between the first and second side portions 420, 428. The intermediate portion is positioned to interact with at least a portion of the LS portion 306 of the tube 112. In other words, the intermediate portion 424 may be a three-layer region of the anvil 402.
[0079] The anvil 402 further comprises first and second transition sections 422 and 426. The first transition section 422 is located between the first side section 420 and the intermediate section 424. In other words, the first transition section 422 is the portion where the anvil 402 transitions from the first side section 402 to the intermediate section 424 (and vice versa). Similarly, the second transition section 426 is located between the intermediate section 424 and the second side section 428. In the second transition section 426, the anvil 402 transitions from the intermediate section 424 to the second side section 428.
[0080] The first and second side sections 420 and 428 correspond to the two-layer region of the tube 112, and the intermediate section 424 may correspond to the three-layer region of the tube 112. In the first and second side sections 420 and 428, the anvil 402 has a first profile 416 when viewed from a direction parallel to the first axis A1. In other words, the ridge 410, support surface 412, and release surface 414 follow the first profile 416 in the first and second side sections 420 and 428. In the intermediate section 424, the anvil 402 has a second profile 418. In other words, the ridge 410, support surface 412, and release surface 414 follow the second profile 416 in the intermediate section 424. The height of the ridge 410 in the first profile 416 is greater than the height of the ridge 410 in the second profile 418. Similarly, the height of the support surface 412 in the first profile 416 is greater than the height of the support surface 412 in the second profile 418. In the illustrated example, the height of the release surface 414 in the first profile 416 is the same as the height of the release surface 414 in the second profile 418. Alternatively, the height of the release surface 414 in the first profile 416 may be greater than the height of the release surface 414 in the second profile 418. The first profile 416 and the second profile 418 of the anvil 402 will be further described in relation to Figures 5A to 5C.
[0081] In the embodiment shown in Figure 4B, the transition from the first side portion 420 through the intermediate portion to the second side portion 428 is asymmetrical. In this embodiment, as will be further explained in relation to Figure 5C, this is achieved by making the widths of the first transition portion 422 and the second transition portion 426 different. In the example shown in Figure 4B, the first transition portion 422 is narrower than the second transition portion 426. Therefore, a steeper transition is obtained in the first transition portion 422 than in the second transition portion 426. Alternatively, the transition portions may be symmetrical.
[0082] Figure 4B further shows a cross-section of the tube 112 of the packaging material, including the longitudinal seal, to illustrate how the anvil 402 is configured to interact with the tube 112. As previously mentioned, the longitudinal seal is asymmetrical due to the overlapping of the packaging materials and the presence of the LS strip 314. Specifically, the longitudinal seal has an uncovered edge (i.e., a portion where the edge of the packaging material is exposed) and a covered edge (i.e., a portion where the other edge of the packaging material is protected by the other part of the packaging material). The steep transition in this embodiment (here, the first transition 422) contributes to improving the sealing performance of the uncovered edge of the longitudinal seal by providing high pressure to the corresponding region of the packaging material. This also improves the handling of molten plastic at the uncovered edge. For the covered edge of the longitudinal seal, the gently sloping transition (i.e., the second transition 426) improves the pressure distribution at the gentler transition from three layers to two layers of packaging material (compared to the uncovered edge). However, an asymmetrical transition adapted for longitudinal sealing may be implemented, in which case the first transition portion 422 will have a wider structure than the second transition portion 426.
[0083] In the example shown in Figure 4B, the packaging material of tube 112 is positioned so that the overlapping side, i.e., the uncovered edge, faces the anvil side. However, the overlapping portion may be positioned so that it faces the ultrasonic generator side. In this alternative example, although some adjustments may be necessary, the same basic principles as in the currently illustrated example are applicable.
[0084] It should be noted that this embodiment should be understood as a non-limiting example of the subject matter currently disclosed. The anvil 402 may have more or less asymmetry in the transition between, for example, the first side portion 420, the second side portion 428 and the intermediate portion 424. Here, asymmetry means any difference in shape from the centerline of the intermediate portion 424 or the centerline of the anvil 402. Asymmetry can be achieved, for example, by making the widths of the first and second transition portions different. Alternatively, or in combination, the first and second transition portions may have different transition shapes. The transition portions may have different inclination angles. The transition portions may have a constant inclination as shown in the figures. Therefore, the transitions of the first and second transition portions may differ in terms of the amount of inclination. Alternatively, the transition may be stepwise. The transition portion may have, for example, two or more different inclinations. Or, the transition portion may have a gradually increasing / decreasing inclination. Therefore, in the most extensive example of the asymmetric anvil 402, the anvil may be asymmetric in that the transitions of the first transition section and the second transition section are different from each other. The first and second transition sections 422, 426 may differ from each other, for example, in the width of each section, the shape of the transition section, and / or the inclination of the transition section. This asymmetry can be confirmed, for example, with respect to the center line of the intermediate section 424.
[0085] The anvil 402 may further include a recess 434 located in the middle section 424 and extending along the second axis A2 of the anvil. This recess provides a mark on the lateral seal and can be used to evaluate the quality of the lateral sealing process by indicating whether the packaging material has shifted within the ultrasonic sealing system 200. As an alternative to the recess 434, a projection extending along the second axis A2 may be provided.
[0086] The anvil 402 may further include a further recess 404 extending along the first axis A1 for receiving a knife 202 used to cut the tube 112. The sonotrode 406 may also include a corresponding further recess 438 positioned opposite the further recess 404 of the anvil 402, thereby allowing the knife 202 to at least partially enter the sonotrode 406 in the cutting state.
[0087] Figures 5A to 5D show three different profiles of the anvil 402. More specifically, Figure 5A shows, as an example, the first profile 416 of the anvil 402, e.g., the first profile 416 mentioned above in relation to Figures 4A and 4B. Figure 5B shows, as an example, the second profile 418 of the anvil 402, e.g., the second profile 418 mentioned above in relation to Figures 4A and 4B. The first and second profiles 416 and 418 shown in the figures show the profiles of the active surface of the anvil 402 (i.e., the surface that faces the packaging material side during the sealing process) as viewed from a direction parallel to the first axis of the anvil 402 (i.e., as a cross-section along the second axis A2 of the anvil 402). In particular, the first profile 416 shown in Figure 5A shows a cross-section along the line C-C' in the first side portion 420 of the anvil 402, and the second profile 418 shown in Figure 5B shows a cross-section along the line B-B' in the middle portion 424 of the anvil 402 (see Figure 5C).
[0088] On the other hand, Figure 5C shows, as an example, the sweep profile 502 (or transition profile 502) of the anvil 402. In particular, it shows a portion of the sweep profile 502 around the middle section 424 of the anvil. This sweep profile 502 shows the profile of the effective surface of the anvil 402 as viewed from a direction parallel to the second axis A2 of the anvil 402 (i.e., as a cross section along the first axis A1). In particular, this sweep profile shows a cross section along the line A-A' in the ridge 410 of the anvil 402 (see Figures 5A and 5B). If a support surface 412 is present, a similar or analogous sweep profile may be provided.
[0089] Refer to Figures 5A and 5B, and the first and second profiles 416 and 418 of the anvil. The first and second profiles 416 and 418 show the case where the anvil 416 is configured to seal two consecutive packages, as shown in Figure 4A. Thus, the anvil has a ridge 410, a support surface 412, a release surface 414, and in addition, a further ridge 410', a further support surface 412', and a further release surface 414'. The first and second profiles 416 and 418 are symmetrical with respect to the central axis between the ridge 410 and the further ridge 410'. Thus, what is said about the ridge 410, the support surface 412, and the release surface 414 is also true for the further ridge 410', the further support surface 412', and the further release surface 414'. To avoid unnecessary repetition, only the ridge 410, the support surface 412, and the release surface 414 will be referred to below. Further recesses for receiving the knife may be provided in the center of the illustrated profile, although these are omitted here for the sake of simplicity.
[0090] The ridge 410 has a first height (H1) and a third height (H3) in the first profile 416 corresponding to the first side portion 420 and the second side portion 428 of the anvil, respectively. Preferably, the first height (H1) and the third height (H3) are the same. However, in some embodiments, the first height (H1) and the second height (H3) may be different from each other. In the second profile 418 corresponding to the middle portion 424 of the anvil, the ridge 410 has a second height (H2). The second height (H2) is smaller than the first height (H1) and the third height (H3), as can be seen by comparing the first profile 416 and the second profile 418, which are shown by dashed lines for illustrative purposes in Figure 5B. Placing the ridge 410 at a lower second height in the middle portion 424 is advantageous in that it can compensate for the extra thickness of the tube (due to the longitudinal seal) present in the middle portion 424 of the anvil during the sealing process. For similar reasons, the support surface 412 exhibits a fourth height (H4) in the first profile 416 and a lower sixth height (H6) in the second profile 418. Furthermore, to avoid generating high pressure on the packaging material, it is preferable that the height of the support surface 412 be lower than the height of the ridge 410. Therefore, the fourth height (H4) is lower than the first height (H1) and the third height (H3), and the sixth height (H6) is lower than the second height (H2). Similarly, the release surface 414 may have a lower height than the support surface 412, thereby minimizing or eliminating pressure on the packaging material present on the release surface 414. Therefore, the fifth height (H5) of the release surface 414 in the first profile 416 is lower than the fourth height (H4). Furthermore, the seventh height (H7) of the release surface 414 in the second profile 418 is lower than the sixth height (H6). Preferably, the release surface 414 is the same height as the first profile 416 and the second profile 418. This has the advantage of simplifying the manufacturing of the anvil. Since the general concept is the most important aspect of the present invention, only the difference in relative heights has been discussed above. The exact dimensions of the anvil depend on the packaging material used and the size and shape of the package being manufactured.Furthermore, it should be understood that other parameters of the anvil, such as the width and position of the support surface 412 and ridge 410 along the second direction A2 of the anvil, as well as the shape and inclination of the transition between different parts, may also be changed between the first profile 416 and the second profile 418.
[0091] Figure 5C and the sweep profile 502 will be described below. As previously mentioned, the anvil comprises a first side section 420, a second side section 428, an intermediate section 424, and a first transition section 422 and a second transition section 426. The sweep profile 502 shows the transition of the ridge 410 along the first axis of the anvil (i.e., the lateral direction of the tube during the sealing process). As shown in Figures 5A and 5C, the ridge has a first height (H1) at the first side section 420, a second height (H2) at the intermediate section 424, and a third height (H3) at the second side section 428. In this embodiment, the first height (H1) and the third height (H3) are the same. Therefore, at the first transition section 422, the ridge transitions from the first height (H1) to the second height (H2) across the first width (W1) of the first transition section 422. In other words, the ridge transitions between a first height (H1) and a second height (H2) in the first transition section. The first transition section 422 has a first width (W1). Correspondingly, in the second transition section 426, the ridge transition from the second height (H2) to the third height (H3) occurs across the second width (W3) of the second transition section 426. In other words, in the second transition section 426, the ridge transitions between a second height (H2) and a third height (H3). The second transition section 426 has a second width (W2). Furthermore, the intermediate section 424 has a third width (W3). The third width (W3) of the intermediate section 424 can also be adapted based on the package being manufactured. For example, it can be wider or narrower than shown. The intermediate section 424 may be, for example, the center point of the anvil 402 (along the first axis A1).
[0092] To provide an asymmetrical transition profile 502, the first width (W1) of the first transition section 422 is smaller than the second width (W2) of the second transition section 426. However, it should be understood that the reverse case, i.e., when the first width (W1) is larger than the second width (W2), is also possible.
[0093] As described above, the asymmetric profile further improves the pressure distribution in the lateral seal cross-section, particularly enhancing sealing performance in TS-LS cross-sections. Furthermore, the smooth transition between the first profile 416 and the second profile 418 reduces the anvil's sensitivity to longitudinal seal misalignment, as will be explained later in Figures 6A to 6C below.
[0094] It should be understood that different degrees of asymmetry can be achieved in the concept of the present invention. As an example, Figure 5D shows an alternative sweep profile 504 with less noticeable asymmetry. Furthermore, in the example of Figure 5D, the second width (W2) of the second transition section 426 is smaller than the first width (W1) of the first transition section 422.
[0095] The sweep profile of the anvil may be adapted, for example, by varying the first height (H1), second height (H2), and third height (H3), as well as the first width (W1), second width (W2), and third width (W3). Advantageously, the first width (W1), second width (W2), and third width (W3) may be set based on the width of the longitudinal seal portion of the tube to be sealed. Preferably, they are set so that the required energy distribution in the longitudinal seal portion is achieved. The first height (H1), second height (H2), and third height (H3) may be set based on the thickness of the packaging material.
[0096] Different heights are shown relative to a common baseline, indicated by a dashed line in the diagram, to illustrate their relationship to one another. However, it should be noted that height can be defined from any suitable position, line, or plane on the anvil.
[0097] Figures 6A to 6C show different positional relationships between the longitudinal seal portion and a part of the anvil. In particular, Figure 6B shows a typical case in which the longitudinal seal portion 306 of the tube 112 is aligned in a preferred manner with the intermediate portion 424, the first transition portion 422, and the second transition portion 426. On the other hand, Figure 6A shows the state in which the tube 112 is shifted by a first distance to the right in the figure (i.e., in the opposite direction to the illustrated first axis A1), and the longitudinal seal portion 306 has moved toward the second side portion 428 of the anvil 402. Finally, Figure 6C shows the state in which the tube 112 is shifted by a second distance to the left in the figure (i.e., in the direction of the illustrated first axis A1), and the longitudinal seal portion 306 has moved toward the first side portion 420 of the anvil 402.
[0098] As shown in Figures 6A to 6C, deviations are expected in the packaging machine where the longitudinal seal portion 306 is positioned relative to the anvil 402 due to web variations and other inaccuracies. The proposed asymmetrical transition profile enables a more robust anvil 402, in the sense that it can form a sufficient lateral seal even when such displacements occur. This is further attributed to the fact that the transition between the first and second profiles is smooth rather than abrupt (i.e., the first and second transition portions 422 and 426 are spread apart).
[0099] Figure 7 illustrates an anvil 402 in a perspective view. Figure 7 further shows the directions of the first axis A1 and the second axis A2 of the anvil 402, which are perpendicular to each other. During operation, the first axis A1 coincides with the lateral direction of the tube, and the second axis A2 coincides with the longitudinal direction (or feed direction) of the tube. Figure 7 further shows the portion of the anvil having the first profile 416 and the second profile 418. As previously mentioned, the first profile 416 is provided on the first and second sides of the anvil, corresponding to the outer portion of the anvil 402 (with respect to the first axis A1). The second profile 418 is provided in the middle portion of the anvil 402 and corresponds to the region where the longitudinal seal portion of the tube is housed (here, the center of the anvil 402).
[0100] The anvil 402 further comprises a further recess 404 for receiving a knife, as described above. The anvil 402 further comprises mounting means 702 for mounting the anvil 402 inside the packaging machine.
[0101] Figure 8 is a flowchart showing the steps of Method 800, which seals a tube 112 of packaging material laterally using the ultrasonic sealing system 200 described above. Method 800 may also be a method of operating the ultrasonic sealing system 200. The packaging material comprises a cardboard layer and plastic foil attached to the cardboard layer. The steps will be described in detail below with reference to Figure 8. The order shown is an example, and the steps of Method 800 may be performed in any suitable order, in parallel, or multiple times. For example, as will be described later, steps S804 and S806 can be performed at least partially simultaneously.
[0102] Method 800 includes the step (S802) of supplying the lateral seal portion 302 of the packaging material tube 112 between the ultrasonic generator 400 and the anvil 402 of the ultrasonic sealing system 200.
[0103] This method further includes a step (S804) of generating ultrasonic vibrations using the sonotrode 406 of the ultrasonic generator 400, thereby melting at least partially the plastic foil of the packaging material in the lateral sealing portion 302.
[0104] Furthermore, this method includes a step (S806) of pressing the tubes 112 against each other in the lateral seal portion 302 between the ultrasonic generator 400 and the anvil 402, thereby creating pressure in the lateral seal portion 302, which adheres the plastic foil and forms a lateral seal. The step of pressing the tubes (S806) may include engagement of the clamp unit 408 with the support surface and / or release surface of the anvil.
[0105] The step of generating ultrasonic vibrations (S804) and the step of pressing the tube against the lateral seal portion (S806) may be performed simultaneously.
[0106] Furthermore, where the disclosure is described as a method, it is understood that it may be embodied as an apparatus or device comprising one or more processors and one or more memories connected to one or more processors, and containing computer code loaded to carry out the method. For example, one or more memories may, in some embodiments, store one or more computer programs that, when executed by one or more processors, perform steps, services, and functions of the method disclosed herein.
[0107] Furthermore, by examining the drawings, disclosures, and attached claims, a person skilled in the art can understand and implement variations of the disclosed modifications.
Claims
1. An anvil (402) of an ultrasonic sealing system (200) for sealing a lateral sealing portion (302) of a tube (112) of packaging material laterally, wherein the lateral sealing portion (302) has a first lateral edge portion (304), a longitudinal sealing (LS) portion (306), and a second lateral edge portion (308), and the anvil (402) is A release surface (414) extending along the first axis (A1) of the anvil (402), The support surface (412) extends along the first axis of the anvil (402) and is positioned between the ridge (410) and the release surface (414), Equipped with, The anvil (402) comprises a first side portion (420), a second side portion (428), an intermediate portion (424), a first transition portion (422) positioned between the first side portion (420) and the intermediate portion (424), and a second transition portion (426) positioned between the intermediate portion (424) and the second side portion (428). In the first side portion (420) and the second side portion (428), the ridge (410), the release surface (414), and the support surface (412) are made according to the first profile (416). In the intermediate portion (424), the ridge (410), the release surface (414), and the support surface (412) are arranged according to the second profile (418). The heights of the ridge (410) and support surface (412) in the first profile (416) are greater than the heights of the ridge (410) and support surface (412) in the second profile (418), and the height of the release surface (414) in the first profile (416) is the same as the height of the release surface (414) in the second profile (418). Anvil (402).
2. In the first transition section (422), the ridge (410) and the support surface (412) transition from the first height (H1) and second height (H2) of the first side section (420) to the third height (H3) and fourth height (H4) of the intermediate section (424) across the first width (W1) of the first transition section (422). In the second transition section (426), the ridge (410) and the support surface (412) transition from the third height (H3) and fourth height (H4) of the intermediate section (424) to the fifth height (H5) and sixth height (H6) of the second side section (428) across the second width (W2) of the second transition section (426). The first width (W1) of the first transition section (422) is smaller than the second width (W2) of the second transition section (426). The anvil (402) according to claim 1.
3. The first height (H1) is the same as the fifth height (H5), and the second height (H2) is the same as the sixth height (H6). The anvil (402) according to claim 2.
4. The intermediate portion (424) further comprises a recess (434) that is located therein and extends along the second axis (A2) of the anvil, An anvil (402) according to any one of claims 1 to 3.
5. The width of the first transition section (422), the width of the second transition section (426), and the width of the intermediate section (424) are set based on the width of the longitudinal sealing section. An anvil (402) according to any one of claims 1 to 3.
6. An ultrasonic sealing system (200) for sealing a lateral sealing portion (302) of a tube (112) of packaging material, wherein the lateral sealing portion (302) comprises a first lateral edge portion (302), a longitudinal sealing (LS) portion (306), and a second lateral edge portion (308), The ultrasonic sealing system (200) is An ultrasonic generator (400) is provided, which is arranged to transmit ultrasonic vibrations to the lateral sealing portion of the tube (112) and includes a sonotrode (406) and a clamp unit (408). An anvil (402) is positioned opposite the ultrasonic generator (400), Equipped with, The aforementioned anvil (402) is A release surface (414) extending along the first axis (A1) of the anvil (402), The support surface (412) extends along the first axis of the anvil (402) and is positioned between the ridge (410) and the release surface (414), Equipped with, The anvil (402) comprises a first side portion (420), a second side portion (428), an intermediate portion (424), a first transition portion (422) positioned between the first side portion (420) and the intermediate portion (424), and a second transition portion (426) positioned between the intermediate portion (424) and the second side portion (428). In the first side portion (420) and the second side portion (428), the ridge (410), the release surface (414), and the support surface (412) are made according to the first profile (416). In the intermediate portion (424), the ridge (410), the release surface (414), and the support surface (412) are arranged according to the second profile (418). The heights of the ridge (410) and support surface (412) in the first profile (416) are greater than the heights of the ridge (410) and support surface (412) in the second profile (418), and the height of the release surface (414) in the first profile (416) is the same as the height of the release surface (414) in the second profile (418). Ultrasonic sealing system (200).
7. In the first transition section (422), the ridge (410) and the support surface (412) transition from the first height (H1) and second height (H2) of the first side section (420) to the third height (H3) and fourth height (H4) of the intermediate section (424) across the first width (W1) of the first transition section (422). In the second transition section (426), the ridge (410) and the support surface (412) transition from the third height (H3) and fourth height (H4) of the intermediate section (424) to the fifth height (H5) and sixth height (H6) of the second side section (428) across the second width (W2) of the second transition section (426). The first width (W1) of the first transition section (422) is smaller than the second width (W2) of the second transition section (426). The ultrasonic sealing system (200) according to claim 6.
8. The ridge (410) is positioned to face the sonotrode (406) of the ultrasonic generator (400). The support surface (412) and the release surface (414) are arranged to face the clamp unit (406) of the ultrasonic generator (400). The ultrasonic sealing system (200) according to claim 6 or 7.
9. The surface (430) of the sonotrode (406) and the surface (432) of the clamp unit (408) positioned toward the anvil (402) are on the same plane. An ultrasonic sealing system (200) according to any one of claims 6 to 8.
10. The clamp unit (408) is subjected to a load by a spring. An ultrasonic sealing system (200) according to any one of claims 6 to 9.
11. The support surface (412) and / or the release surface (414) and / or the surface (432) of the clamp unit (408) are made of an elastic material. An ultrasonic sealing system (200) according to any one of claims 6 to 10.
12. A packaging machine (100) equipped with a transverse sealing (TS) station (114) for sealing a tube (112) of packaging material laterally and cutting it into a package (116), The TS station (114) comprises an ultrasonic sealing system (200) according to any one of claims 6 to 11. Packaging machine (100).
13. The intermediate portion (424) is arranged to interact with at least the LS portion (418) of the tube in a lateral sealed state. The first side portion (420) and the second side portion (428) are arranged to interact with the first lateral edge portion (416) and the second lateral edge portion (420) of the tube (112), respectively, when in a lateral sealed state. The packaging machine (100) according to claim 12.
14. The packaging material comprises a cardboard layer and a plastic foil attached to the cardboard layer, and does not contain aluminum. The packaging machine (100) according to claim 12 or 13.
15. A method (800) for sealing a tube (112) of packaging material laterally using an ultrasonic sealing system (200) according to any one of claims 6 to 11, wherein the packaging material comprises a cardboard layer and a plastic foil attached to the cardboard layer. The above method (800) is, The lateral sealing portion (302) of the tube (112) of the packaging material is supplied between the ultrasonic generator (400) and the anvil (402) (S802). Using the sonotrode (406) of the ultrasonic generator (400), ultrasonic vibrations are generated (S804) to at least partially melt the plastic foil of the packaging material in the lateral sealing portion (302), Between the ultrasonic generator (400) and the anvil (402), the tube (112) within the lateral sealing portion (302) is pressed against each other (S806), pressure is formed in the lateral sealing portion (302), the plastic foil is attached and the lateral seal is formed. A method (800) comprising: