Hollow cooling bar with double venturi structure

Abstract

A double Venturi structure hollow cooling rod consists of an inner Venturi channel, an outer Venturi channel, and a tipping paper covering the outer Venturi channel. The inner Venturi channel is formed by multiple axially extending inner Venturi cavities through the filter rod body after pressing. The outer Venturi channel is formed by multiple axially extending outer Venturi cavities through the outer wall of the filter rod body and the covering forming paper or tipping paper after pressing. After connecting to a cigarette, smoke can pass through the inner and outer channels, providing a good cooling effect and a large smoke volume when used to heat the cigarette.

Description

Technical Field

[0001] This invention belongs to the field of novel tobacco technology, specifically relating to a hollow cooling rod with a double Venturi structure. Background Technology

[0002] Cigarette smoke exists in an aerosol state, with aerosol particles consisting of tiny droplets. Smoke temperature directly affects the particle size and composition of aerosols, thus influencing the amount of harmful components in the smoke and the sensory quality of the cigarette. When the smoke temperature is too high, the burning sensation and irritation increase significantly, especially in heated cigarettes. Reducing the smoke temperature is a key technological direction for the continuous improvement of such products.

[0003] For heated cigarettes, the amount of smoke produced during inhalation is directly related to the draw resistance and filtration efficiency of the filter rod. When the draw resistance is high and the filtration efficiency is high, more smoke aerosol is adsorbed by the filter rod, resulting in less smoke and a poorer experience and satisfaction for the smoker. Conversely, when the draw resistance is low and the filtration efficiency is low, more smoke is produced, resulting in a better experience and satisfaction for the smoker. Reducing draw resistance is also a key technological direction for the continuous improvement of heated cigarette products. For traditional cigarettes, higher smoke temperatures can lead to greater spiciness and a poor sensory experience; appropriately lowering the smoke temperature can also help improve cigarette quality.

[0004] CN112930121A discloses an aerosol generation system incorporating a Venturi element. The use of the Venturi element reduces the cooling stage, demonstrating that the Venturi structure has a certain cooling effect. The Venturi element described in the literature is a standard Venturi structure with an air introduction channel, making it relatively complex, difficult to manufacture, and costly. It is suitable for repeated use with smoking devices (heaters) but not for single-use heated cigarettes.

[0005] Our previous studies (CN111387543A, CN111387546A, CN111436650A) have shown that when cigarette smoke passes through a hollow rod similar to a Venturi tube or corrugated tube, the diameter of the internal cavity changes continuously from contraction to expansion, resulting in a strong turbulent flow of the smoke. This not only reduces the adsorption of smoke aerosols on the tube wall, ensuring the amount of smoke, but also enhances the heat transfer coefficient, which is 2-4 times that of ordinary hollow tubes, thus increasing the heat transfer and cooling effect. On the other hand, the smoke aerosols also undergo a process of turbulent collision and collision coagulation during expansion, followed by dispersion and atomization during contraction. During secondary atomization, the specific surface area increases, absorbing heat from the air and further reducing the smoke temperature.

[0006] Currently, some heated cigarettes on the market experience filter shrinkage due to heat during smoking, which can clog the smoke passage and cause a significant decrease in smoke volume in the latter part of the cigarette. However, if a double Venturi channel is used, this filter shrinkage and clogging problem will not occur. Even if the filter near the smoke-generating section shrinks, its diameter decreases, and the internal Venturi channel becomes smaller or completely blocked, the outer cavity, i.e., the outer Venturi channel, will enlarge, allowing smoke to still pass through without a significant decrease in smoke volume.

[0007] To address the aforementioned issues, further enhance the cooling effect of flue gas, develop differentiated products that can be industrially and continuously produced, meet the requirements of single-use heated cigarettes, and adapt to the needs of different consumers, we have also conducted research on filter rods with an inner and outer double Venturi structure. Summary of the Invention

[0008] The technical problem this invention aims to solve is to provide a hollow cooling rod with a double Venturi structure. This rod alters the flue gas flow path, resulting in a significant cooling effect. Because the diameters of the inner and outer cavities continuously change from contraction to expansion, the flue gas is in a state of intense turbulence. This not only reduces the adsorption of flue gas aerosols on the tube wall, ensuring sufficient smoke volume, but also achieves a heat transfer coefficient 2-4 times that of ordinary hollow tubes, resulting in better heat transfer and cooling. Furthermore, the flue gas aerosols undergo a process of turbulent collision and agglomeration during expansion, followed by dispersion and atomization during contraction. The increased surface area during secondary atomization absorbs heat from the air, further reducing the flue gas temperature and significantly decreasing the burning sensation and irritation during inhalation. Since this filter rod has a straight-through structure, when used to heat cigarettes, it ensures sufficient atomization of the cigarette while simultaneously cooling it, satisfying the smoker's experience. The dual-channel design also solves the problem of channel blockage and a significant decrease in smoke volume in the latter half of the inhalation process in some heated cigarettes currently on the market.

[0009] The technical solution of the present invention is: a hollow cooling rod with a double Venturi structure, which consists of an inner Venturi channel, an outer Venturi channel and a splicing paper covering the outer Venturi channel;

[0010] The inner venturi channel is formed by multiple inner venturi cavities that extend axially through the filter rod body after it has been pressed.

[0011] External Venturi channels are channels formed along the axial direction by the outer wall of the filter rod body and the covering molding paper or tipping paper after the filter rod body is pressed.

[0012] After connecting to the cigarette, the smoke can pass through two channels, one inside and one outside, which has a good cooling effect and a large amount of smoke when used to heat the cigarette.

[0013] The filter rod body has a certain degree of elasticity and strength, with a hardness ≥84% and a minimum wall thickness b ≥0.5mm.

[0014] The inner venturi channel is formed by multiple inner venturi cavities and multiple inner venturi throat cylindrical tubes that are connected alternately along the axial direction.

[0015] The cross-section of the inner Venturi cavity is an irregular structure, including any one of polygonal, circular, star-shaped, heart-shaped, plum blossom-shaped, leaf-shaped, or arc-shaped, with a circular shape being preferred.

[0016] The maximum nominal diameter d2 of the inner Venturi cavity is 2mm-6mm, and the cavity length L2 is 5mm-60mm;

[0017] The nominal diameter d1 of the cavity of the cylindrical tube in the throat of the internal Venturi is ≤2mm, and the length L1 is 0.5mm-10mm;

[0018] The length of the Neventuri cavity is 1 to 50 times the length of the cylindrical tube in the throat of the Neventuri.

[0019] Variations in the size of d1 significantly affect the draw resistance and smoke volume of the filter rod, and also have some impact on the cooling effect. When using the tow drawing process, the solid part 21 of the Venturi rod also has a certain degree of air permeability. When d1=0mm, the gaps inside the solid part act as a throat channel. Although the draw resistance increases to some extent, it can still meet the design requirements of some cigarettes. When using the injection molding process, the air permeability of the filter rod body is very low, and the smoke mainly passes through the double Venturi channels. When d1≤0.3mm, the draw resistance of the filter rod is >12Pa / mm, the smoke volume decreases, and the proportion of smoke passing through the outer Venturi channel increases, which can cause mouth burning and is not suitable for heating cigarettes. As d1 increases, the draw resistance decreases and the smoke volume increases. When d1≥2mm, the draw resistance of the filter rod is <1Pa / mm, and it needs to be combined with other filter rods before it can be used for heating cigarettes. d2 also has a certain impact on thermal collapse, smoke volume, and the overall quality of the cigarette. When d2 < 2mm, thermal collapse and off-flavors occur, and the cooling effect is also poor. When d2 ≥ 2.0mm, thermal collapse improves, smoke volume increases slightly as d2 increases, and the cooling effect further improves. When d2 ≥ 3.5mm, smoke volume and cooling effect tend to stabilize. Meanwhile, since the diameter of the cigarette is usually < 7.7mm, and considering that the Venturi rod has certain wall thickness and hardness requirements, the maximum value of d2 is set to ≤ 6mm.

[0020] When the total length of l1+l2 remains constant, increasing the length of l1 increases the suction resistance and decreases the amount of smoke. Generally, l1≤5.0mm is selected.

[0021] The cross-sectional shape of the inner Venturi cavity and the cylindrical tube of the inner Venturi throat can be the same or different; the inner Venturi cavity is composed of irregularly shaped curved tubes with gradually increasing and equal diameters and gradually decreasing diameters along the nominal diameter; the gradual increase and decrease along the axial direction are equal-distance gradual increase and gradual decrease; the inner Venturi cavities with gradually increasing and decreasing nominal diameters are arc-shaped, conical, or plateau-shaped along the axial direction; at both ends of the same cavity unit, the arc and conical tubes preferably have the same and symmetrical arc and angle.

[0022] The external Venturi channel consists of an outer wall of a body portion with axial grooves and a corrugated tube shape along the axial direction, and an outer covering of molded paper. The cross-section of the filter rod body is a grooved arc shape.

[0023] The groove depth of the exoventuri channel is 0.05mm-1.0mm, and the number of grooves is 1-30, preferably 1-12 evenly distributed along the circumference; the difference between the maximum and minimum diameters of the exoventuri cavity is 0.1-2mm, preferably 0.1-1mm.

[0024] When the maximum and minimum diameters of the outer Venturi cavity deviate too much, it will make cigarette splicing more difficult. To facilitate cigarette splicing, d4-d3 is usually ≤1mm. The depth and number of grooves determine the size of the neck channel of the outer Venturi. If it is too large, more smoke will pass through the external channel, increasing the amount of smoke. However, this will cause the temperature of the external forming paper and splicing paper to rise, which may burn the mouthpiece in severe cases. Therefore, the groove depth should be controlled within 1.0mm, and usually the groove depth is ≤0.3mm. The cavity of the outer Venturi channel is relatively small. In heating cigarettes, it plays an auxiliary role in cooling and increasing the amount of smoke. Compared with the single inner Venturi channel, the cooling and smoke-increasing principle of its throat groove section and cavity section is the same as that of the corresponding section of the inner Venturi. It can help reduce the smoke temperature by 1-3℃ and increase the amount of smoke by 5%-20%.

[0025] In extreme cases, when the number of grooves on the outer wall of the main body is 0, when connecting cigarettes or wrapping the forming paper, the circumference of the cigarette or filter rod is increased by 0.05-0.1mm, so that there is a small gap between the filter rod body and the forming paper, thereby forming the throat channel of the outer Venturi, which can also achieve the effect of opening 4-6 grooves on the outer wall.

[0026] If the outer Venturi channel has no groove, the roundness of the filter rod body is increased to 0.35-0.60mm, so that there is a small gap between the filter rod body and the forming paper, thereby forming the throat channel of the outer Venturi and forming a double Venturi structure.

[0027] The inner and outer walls of the inner and outer Venturi channels are both smooth structures.

[0028] The main material is any one of the following polymer materials: PP, PE, PET, PLA, PC, PS, PA, PCL, PHA, PHB, PBS, PGS, PEA, PPS, ABS, PVC, PBAT, PEEK, PMMA, or it is composed of cellulose acetate, or a mixture of cellulose acetate tow with one or more of PLA fiber, PP fiber, viscose fiber, polyester fiber, etc., and a curing agent.

[0029] The preparation methods are divided into two types: injection molding and fiber-drawn filter rod molding.

[0030] The injection molding process involves customizing a corresponding mold based on the designed structure of the double Venturi filter rod, and then using the mold for injection molding.

[0031] The aforementioned fiber filter rod forming process involves introducing a fiber bundle material that has been loosened and treated with a curing agent such as triacetyl ester or tributyl citrate into a fiber filter rod forming machine. The fiber bundle material is then introduced into a fiber drawing and shaping smoke gun equipped with a corresponding mold, and the hollow rod that has been cured at high temperature and cooled and shaped is drawn out and cut to prepare the filter rod.

[0032] The fiber bundles are made of cellulose acetate bundles or a mixture of cellulose acetate and polylactic acid fiber bundles. Triacetin or tributyl citrate is applied, and the bundles are introduced into a special smoke gun equipped with a corresponding mold. The bundles are then drawn out and slit after being cured by high temperature with steam and shaped by cold air.

[0033] This invention features a reasonable design, unique structure, novel appearance, and convenient production, with a significant smoke cooling effect. It allows for continuous industrial production while reducing the number of cigarette segments and lowering costs. It can be combined with ordinary filter rods for traditional cigarettes, reducing smoke temperature, decreasing irritation, and improving sensory quality. It can also be used directly or in combination with other filter rods for heated cigarettes. Due to its straight-through structure, the filter rod has low draw resistance, ensuring sufficient atomization while cooling, thus satisfying the smoker's experience. The dual-channel design also solves the problem of channel blockage and significant reduction in smoke volume in the latter half of the smoke in some heated cigarettes currently on the market, providing a new solution for improving cigarette quality and developing new tobacco products. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] Figure 1 This invention provides a fluid flow model inside a bellows.

[0036] Figure 2This is a cross-sectional view of the double Venturi injection molding tube of Embodiment 1 of the present invention. In the figure, 21' is the double Venturi filter rod body, 22' is the inner Venturi cavity, 221' is the inner Venturi throat cylindrical tube, 222' is the inner Venturi curved tube with gradually increasing diameter, and 223' is the inner Venturi curved tube with gradually decreasing diameter; 23' is the outer Venturi cavity, 231' is the outer Venturi throat groove, 232' is the outer Venturi curved tube with gradually increasing diameter, and 233' is the outer Venturi curved tube with gradually decreasing diameter.

[0037] Figure 3 This is a cross-sectional view of the double Venturi cellulose acetate rod of Embodiment 2 of the present invention. In the figure, 21 is the double Venturi filter rod body, 22 is the inner Venturi cavity, 221 is the inner Venturi throat cylindrical tube, 222 is the inner Venturi curved tube with gradually increasing diameter, and 223 is the inner Venturi curved tube with gradually decreasing diameter; 23 is the outer Venturi cavity, 231 is the outer Venturi throat groove, 232 is the outer Venturi curved tube with gradually increasing diameter, and 233 is the outer Venturi curved tube with gradually decreasing diameter.

[0038] Figure 4 This is a cross-sectional view of a three-section cigarette according to an embodiment of the present invention. In the figure, 1 is the cigarette section, 2 is the double Venturi filter section, 3 is the cellulose acetate filter section, 4 is the inner Venturi channel, 5 is the outer Venturi channel, and 6 is the forming paper.

[0039] Figure 5 This is a cross-sectional structural diagram of another embodiment of the present invention. d1' and d2' are the minimum and maximum diameters of the inner Venturi cavity, respectively, d3' and d4' are the minimum and maximum outer diameters of the outer Venturi cavity, respectively, and 21 is the body of the filter rod.

[0040] Figure 6 This is a cross-sectional structural diagram of another embodiment of the present invention, 231, the outer Venturi throat groove.

[0041] Figure 7 This is a cross-sectional structural diagram of another embodiment of the present invention.

[0042] Figure 8 This is a cross-sectional view of a two-section cigarette according to another embodiment of the present invention. 1' is the cigarette section and 2' is the double Venturi filter rod section.

[0043] Figure 9 This is a cross-sectional view of a two-section cigarette according to another embodiment of the present invention. 1” is the cigarette section and 2” is the double Venturi filter rod section.

[0044] Figure 10 This is a cross-sectional view of a two-section cigarette according to another embodiment of the present invention, where 1”' is the cigarette section and 2”' is the double Venturi filter rod section.

[0045] Figure 11This is a cross-sectional view of a two-section heated cigarette stick according to another embodiment of the present invention. 1”” is the cigarette stick segment and 2”” is the double Venturi filter rod segment.

[0046] Figure 12 This is a cross-sectional view of a three-section traditional cigarette stick according to another embodiment of the present invention. 1””’ is the cigarette stick section, 2””” is the double Venturi filter rod section, and 3””” is the cellulose acetate filter section. Detailed Implementation

[0047] Preparation of three-section cigarette samples: First, remove the filter section with tweezers. Then, manually remove the "empty tube section + cooling section" or "cooling section + filter section" of the fiit or Marlboro cartridge with tweezers, being careful not to damage the outer wrapping paper. Then, replace the "empty tube section + cooling section" of the fiit or Marlboro cartridge with the Venturi tube in each embodiment and put the original filter section back in its original position, or replace the "cooling section + filter section" to prepare three-section cigarette samples, with 10 cigarettes for each sample.

[0048] Preparation of two-stage cigarette samples: First, manually remove the "empty tube section + cooling section + filter section" of the fiit and Marlboro cartridges with tweezers, being careful not to damage the outer wrapping paper. Then, replace the "empty tube section + cooling section + filter section" of the fiit and Marlboro cartridges with the Venturi tubes in each embodiment to prepare two-stage cigarette samples, with 10 cigarettes for each sample.

[0049] Inhalation method: The inhalation method was tested according to the national standard for electronic cigarettes. The duration of a single puff was 3.0 s, the inhalation volume was 55.0 mL, the frequency was one puff every 30.0 s, the device was a MYUZ device, the heating time was 5 min, and the number of puffs was 10.

[0050] The preparation method of the double Venturi injection molded tube is described in Example 1, and the preparation method of the double Venturi drawn filter rod is described in Example 2.

[0051] Preparation of two-section and three-section cigarettes: The cigarette material rod, double Venturi rod, and filter section material rod for three-section cigarettes are cut into the designed lengths, and then fed into the binary or ternary composite machine, labeling machine, or cigarette machine in sequence. The outside is wrapped with forming paper or cork paper and glued with interlocking adhesive before being cut into sections.

[0052] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0053] Figure 1This model illustrates fluid flow within a bellows. Along the flow direction, the fluid velocity decreases and static pressure increases at the crests of the bellows, while the velocity increases and static pressure decreases at the troughs. This creates a constant, regular disturbance in velocity and pressure, resulting in strong turbulence and preventing laminar flow. The fluid flows under repeatedly changing velocity and pressure gradients, generating vortices that erode the boundary layer, significantly disrupting its formation. This periodic cross-sectional change increases the turbulence intensity and heat transfer capacity near the pipe wall, enabling turbulent heat transfer and thus improving the heat transfer rate. For flue gas aerosols, this enhances the heat transfer and cooling effect. Furthermore, the flue gas aerosols undergo turbulent collisions and expansion, followed by collisional coagulation and contraction, resulting in atomization and smaller size. During secondary atomization, the surface area increases, absorbing heat from the air and further reducing the flue gas temperature.

[0054] Example 1

[0055] Figure 2 This is a cross-sectional view of the double Venturi injection-molded tube according to an embodiment of the present invention. d1' and d2' are the minimum and maximum diameters of the inner Venturi cavity, respectively, and d3' and d4' are the minimum and maximum outer diameters of the outer Venturi cavity, respectively. The gray shading represents the filter rod body. The inner cavity forms an inner Venturi channel; the outer part is a corrugated tube with axial grooves. After the cigarette is attached, it, together with the tipping paper (tip paper), forms another outer Venturi channel.

[0056] The dimensions are set as follows: d1'=1.2mm, d2'=4.5mm, d3'=6.0mm, d4'=7.0mm; the length of the cylindrical tube portion of the Venturi throat in the inner cavity is l1'=1.67mm, the length of the curved tube portion is l2'=15.0mm, the number of grooves on the outer wall is 4, and the groove depth is 0.5mm; the design model of the filter rod is divided into two parts from the axis, and then a corresponding mold is made according to the shape of the separated filter rod (half). The injection molding grade PLA resin of Zhejiang Haizheng is used for injection molding at 190℃. After the two injection-molded semi-finished products are bonded together, a PLA Venturi rod with 6 cavities and a diameter of 100mm×22mm can be prepared.

[0057] The Venturi rod was cut into four equal parts, each 25mm long, corresponding to 1.5 Venturi units, with one end having a large hole and the other a small hole. The "cooling section + filter section" (25mm long) of the fiit cartridge was manually replaced, with the large and small holes at the lip end respectively, producing 10 three-section cigarette samples. Testing was conducted according to the national standard e-cigarette vaping method: single puff duration 3.0 s, puff volume 55.0 mL, puff frequency one puff every 30.0 s, all MYUZ devices used, heating time 5 min, and 10 puffs per person. The test data showed that the smoke density index (SDI) of the control group was 34.1%, while after replacing with the Venturi tube, the SDI doubled to 65.2%. The smoke temperature at the large lip hole was close to that of the original cigarette, around 45℃, while the smoke temperature at the small lip hole increased to around 52℃. Overall, they can all meet the requirements for heated cigarettes.

[0058] Example 2

[0059] Figure 3 This is a cross-sectional view of a double Venturi cellulose acetate rod according to an embodiment of the present invention. The gray shaded area 21 is the body of the filter rod, where d1 and d2 are the minimum and maximum diameters of the inner Venturi cavity, respectively; d3 and d4 are the minimum and maximum outer diameters of the outer Venturi cavity, respectively; and b and B are the minimum and maximum wall thicknesses of the filter rod body, respectively. The inner blank area 22 is the filter rod cavity of the inner Venturi channel, composed of a cylindrical tube 221 at the Venturi throat, a curved tube 222 with gradually increasing diameter, and a curved tube 223 with gradually decreasing diameter. The outer blank area 23 is the filter rod cavity of the outer Venturi channel, composed of a groove 231 at the outer Venturi throat, a curved tube 232 with gradually increasing diameter, and a curved tube 233 with gradually decreasing diameter, together with the outer forming paper.

[0060] The smoke aerosol exhibits excellent heat transfer and cooling effects as it passes through the inner and outer Venturi channels. Simultaneously, due to the alternating contraction and expansion of the inner and outer cavities, the smoke aerosol undergoes a process of turbulent collision and condensation during expansion, followed by dispersion and atomization during contraction. The increased surface area during secondary atomization absorbs heat from the air, further reducing the smoke temperature. The straight-through Venturi channel structure of the filter rod also results in low draw resistance. Furthermore, by adjusting the size of the Venturi throat channel d1 and the number and depth of grooves on the outer wall, the draw resistance and the amount of smoke in the cigarette can be further adjusted. When used for heating cigarettes, it ensures the required amount of atomization while simultaneously cooling, catering to the individual preferences of different smokers.

[0061] exist Figure 3In the extreme states, when d1=d2=0, the internal cavity is a solid structure, and the filter rod becomes a single external Venturi filter rod; when d3=d4 and the number of grooves on the outer wall is 0, the outer wall becomes a smooth cylinder, and the filter rod becomes a single internal Venturi filter rod; when d1=d2>0, d3=d4, and the number of grooves on the outer wall is 0, it becomes a regular hollow filter rod. Figure 3 In order to ensure the strength and performance of the double Venturi filter rod, the minimum wall thickness b of the filter rod body is ≥0.5mm.

[0062] On a fiber-drawing filter rod forming machine with two sets of opening systems, two 6.0Y36000D cellulose acetate filament bundles are guided into their respective opening systems via two sets of filament guiding devices. The opening roller pressure is 0.25MPa, and the roller speed ratio of the two opening rollers is 1:1.3~1.4. Triacetin with a mass fraction of 15% is sprayed onto the opened filament bundles. The two filament bundles from the upper and lower layers are then mixed together by the filament guiding devices to form a mixed filament bundle. The filament bundle is then introduced into a special mold, rapidly cured with 0.1~0.3MPa steam, and then shaped with 10℃, 0.1MPa cold air before being fed into a smoke gun. The preliminarily cured filament bundles are further wrapped with a cloth belt and then drawn into shape. After slitting and packaging, the product is prepared as shown in the attached image. Figure 3 The structure shown is a double Venturi cooling rod.

[0063] By selecting different molds and cutting lengths, a series of double Venturi filter rods with diameters of 6.7mm-7.5mm, lengths of 100mm, 120mm, and 132mm, and 2-12 holes can be prepared.

[0064] With d1=0.8mm, d2=4.0mm, d3=6.5mm, d4=7.0mm, 6 grooves on the outer wall, a groove depth of 0.2mm, l1=2mm, and l2=14.5mm, a double Venturi filter rod with 8 holes and a diameter of 132mm×22.0mm×700Pa can be prepared using the corresponding mold. This filter rod can be cut into 4 sections to prepare... Figure 9 As shown, this is a heated non-combustible cigarette with a cylindrical perforation that connects to the cigarette, a perforation at the lip end, and two complete internal cavities.

[0065] Using this Venturi stick, the "empty tube section + cooling section + filter section" of the Marlboro e-cigarette cartridge were manually replaced, with a small hole at the lip end, to create 10 two-section e-cigarette samples. Each sample contained two Venturi units. Testing was conducted according to the national standard e-cigarette puffing method: single puff duration 3.0 s, puff volume 55.0 mL, puff frequency one puff every 30.0 s, all using MYUZ e-cigarettes, heating time 5 min, and 10 puffs per person. The data showed that the smoke density index (SDI) of the control group was 35.2%. After replacing with the Venturi tube, the SDI increased by 60% to 56.3%, but later decreased to near the original smoke, and the smoke temperature increased by about 10°C to 57.2°C. A slight burning sensation and odor were observed. After the e-cigarette was finished, the filter tip was peeled back, and thermal collapse and shrinkage of the small hole at the contact point with the smoke-generating section were observed.

[0066] Example 3

[0067] In Example 2, by changing the cutting position, the filter rod can be used to prepare an attached... Figure 8 As shown, the heated cigarette has a structure containing two Venturi units, with the large-hole portion of the inner cavity connecting to the cigarette and the lip end also having a large hole. Using this Venturi rod, the "empty tube section + cooling section + filter section" of the Marlboro cartridge were manually replaced, with large holes at both the cigarette end and the lip end, to produce 10 two-section cigarette samples. The sample cigarettes contained two Venturi units. The tests were conducted according to the national standard for electronic cigarettes, with a single puff duration of 3.0 s, a puff volume of 55.0 mL, a puff frequency of one puff every 30.0 s, all using MYUZ devices, a heating time of 5 min, and 10 puffs. According to the test data, the smoke concentration index (SDI) of the control group was 35.2%, and the amount of smoke decreased in the latter half. After switching to the double Venturi filter rod with this structure, the smoke concentration index (SDI) increased by 70% to 59.8%, and the amount of smoke in the front and back sections remained unchanged. The overall amount of smoke increased and the uniformity improved. The smoke temperature was close to that of the original cigarette, at about 45°C, with no burning sensation or odor. After the cigarette was finished, the filter tip was peeled off, and the large hole at the front end that contacted the smoke-generating section did not collapse due to heat. The overall quality of this heated cigarette has been improved.

[0068] Example 4

[0069] In Example 3, two rows of holes were drilled within a 2-5mm range at the outlet of the smoking device, with a row spacing of 2mm and 6 holes per row, each with a hole diameter of 0.2mm. Test results showed that the Smoke Concentration Index (SDI) increased by 20% to 71.6%, while the amount of smoke at both ends remained unchanged. The overall smoke volume was relatively large, and the smoke temperature decreased by about 5℃ to 39.6℃. There was no burning sensation, irritation, or odor, resulting in a good overall user experience.

[0070] In Examples 3-4, the appendix is ​​used. Figure 8 The cigarette and filter rod structures shown demonstrate that adjusting the size of d1 significantly affects the filter rod's draw resistance and smoke volume, and also has some impact on the cooling effect. When d1 = 0 mm, the internal gaps of the solid part act as a throat channel, resulting in good cooling, but the filter rod's draw resistance is >10 Pa / mm, leading to significant filtration of the smoke and a decrease in smoke volume. As d1 increases, the draw resistance decreases and the smoke volume increases. When d1 > 2 mm, the filter rod's draw resistance is <1 Pa / mm, requiring combination with other filter rods before it can be used in cigarettes. d2 also has a certain impact on thermal collapse, smoke volume, and the overall quality of the cigarette. When d2 < 2 mm, thermal collapse and off-flavors occur, and the cooling effect is poor. When d2 ≥ 2.0 mm, thermal collapse improves, and as d2 increases, the smoke volume slightly increases, further improving the cooling effect. When d2 ≥ 3.5 mm, the smoke volume and cooling effect tend to stabilize. When the total length of l1+l2 remains constant, increasing the length of l1 increases the suction resistance and decreases the amount of smoke. Generally, l1≤5.0mm is selected.

[0071] To facilitate cigarette loading, the groove depth is typically ≤0.3mm, with d4-d3 ≤1mm. The cavity of the outer Venturi channel is relatively small, playing a role in assisting in cooling and increasing the amount of smoke during cigarette heating. Compared with the single inner Venturi channel, the cooling and smoke-increasing principles of its throat groove and cavity sections are the same as the corresponding sections of the inner Venturi, which can help reduce the smoke temperature by 1-3℃ and increase the smoke volume by 5%-20%.

[0072] In this embodiment, d4 remains unchanged, and the number of grooves on the outer wall of the main body is set to 0. When connecting cigarettes or wrapping forming paper, the circumference of the cigarette or filter rod is increased by 0.05-0.1mm, so that there is a small gap between the filter rod body and the forming paper, thereby forming the throat channel of the outer Venturi, which can also achieve the effect of opening 4-6 grooves on the outer wall.

[0073] Example 5

[0074] In Example 2, keeping d1=1.2mm, d2=4.5mm, d3=6.5mm, d4=7.0mm, the number of grooves on the outer wall remains 6, and the groove depth remains 0.2mm. Adjusting L1=3mm and L2=30mm, a Venturi filter rod measuring 132mm×22.0mm×400Pa with 4 holes can be prepared using a corresponding mold. This filter rod is then cut into 4 sections and joined with cigarettes to produce a... Figure 10As shown, the large-hole portion of the inner cavity connects with the cigarette, and the lip end also has a large hole. It is a heated cigarette composed of one double Venturi unit (two "semi-cavities"). Using this Venturi rod, the "empty tube section + cooling section + filter section" of the Marlboro cigarette cartridge were manually replaced. Both the cigarette end and the lip end have large holes. Ten two-section cigarette samples were made, and each sample cigarette contained two Venturi units. The test was conducted according to the national standard electronic cigarette vaping method. The single puff duration was 3.0 s, the puff volume was 55.0 mL, the frequency was one puff every 30.0 s, all smoking devices were MYUZ smoking devices, the heating time was 5 min, and the number of puffs was 10. According to the test data, after switching to this type of double Venturi filter rod, the smoke density index (SDI) increased by 95% to 68.3%, while the amount of smoke in the front and rear sections remained unchanged. The overall amount of smoke increased and became more uniform, with no odor. After the cigarette was finished, the filter tip was peeled off, and the large hole at the front end that was in contact with the smoke-generating section did not collapse due to heat. Compared with the "two double Venturi units" structure in Example 3, the amount of smoke increased by about 15%, and the smoke temperature increased by about 3°C ​​to 48.6°C, which can also meet the differentiated experience of some consumers.

[0075] Example 6

[0076] In Example 2, the following parameters were set: d1=0.8mm, d2=3.0mm, d3=4.92mm, d4=5.19mm, L1=1.5mm, L2=15mm. The double-layered opening machine was replaced with a single-layered opening machine with a 50% wider opening roller. A single 5.0Y45000D cellulose acetate tow was used. The opening roller pressure was 0.25MPa, and the roller speed ratio of the two opening rollers was 1:1.25~1.35. Triacetin (13% by weight of the tow) was sprayed onto the opened tow. The tow was then introduced into a special mold, rapidly cured with 0.1~0.3MPa steam, and then shaped with 15℃, 0.1MPa cold air before being fed into a smoke gun. The preliminarily cured tow strips were further wrapped with a cloth belt, drawn into shape, and then slit and packaged to produce the product shown in the attached image. Figure 3 The double Venturi filter rod shown measures 132mm × 16.5mm × 800Pa and contains 8 cavity units. This filter rod can be used to construct... Figure 8 As shown, the heated cigarette with a "two-Venturi unit" structure was tested according to the national standard e-cigarette smoking method. The single puff duration was 3.0 s, the puff volume was 55.0 mL, and the frequency was one puff every 30.0 s. The smoking devices were all custom-made slim cigarette sets. The heating time was 5 minutes, and the number of puffs was 10. The test results showed a smoke density index (SDI) of 45.8%, a smoke temperature of 46.1℃, no burning sensation, irritation, or off-odor, and good overall quality.

[0077] Figure 5This is a cross-sectional structural diagram of an embodiment of the present invention, wherein d1' and d2' are the minimum and maximum diameters of the inner Venturi cavity, respectively, and d3' and d4' are the minimum and maximum outer diameters of the outer Venturi cavity, respectively. The gray shading 21 is the body of the filter rod, wherein the inner and outer light gray parts represent the partial entities formed during the transition between the body and the cavity.

[0078] Figure 6 This is a cross-sectional structural diagram of embodiments 2-6 of the present invention. The gray shaded part is the body of the filter rod. The light gray parts inside and outside represent the partial entities formed during the transition between the body and the cavity. The cross-section of the inner cavity is circular. The gap 231 on the outer circle is the groove on the outside of the filter rod, which together with the outer forming paper or cork paper forms the outer Venturi throat channel.

[0079] Figure 7 This is a cross-sectional structural schematic diagram of another embodiment of the present invention. Figure 6 Based on this, by changing the preparation mold, the cross-section of the internal cavity can be changed to a pentagonal star shape. After connecting the cigarettes, the internal pentagonal star-shaped cavity can be seen, giving it a novel and unique appearance. Similarly, the shape of the internal cavity can also be changed to a heart shape, plum blossom shape, leaf shape, square shape, rhombus shape, triangle shape, oval shape, etc.

[0080] Figure 11 This is a cross-sectional view of a cigarette according to another embodiment of the present invention, containing three hollow units. In the figure, 1”” is the cigarette segment and 2”” is the double Venturi filter rod segment. In the aforementioned embodiment, the double Venturi filter rod containing three hollow units can be prepared by adjusting the total length of “l1+l2”, and then it can be connected to the cigarette.

[0081] Example 7

[0082] Figure 4 This is a cross-sectional view of a three-section heated cigarette according to another embodiment of the present invention. In the figure, 1 is the cigarette section, 2 is the double Venturi filter section, 3 is the cellulose acetate filter section, 4 is the inner Venturi channel, 5 is the outer Venturi channel, and 6 is the forming paper. The Venturi rod 2 and the cellulose acetate rod 3 are first laminated together before being joined to the cigarette; alternatively, the three parts of the material rods are cut and laminated in one step on a ternary laminating machine. This can meet the requirements of heated cigarettes regarding smoke temperature and atomization volume.

[0083] In Example 5, by adjusting d1=1.0mm, L1=2mm, and L2=23mm while keeping other parameters unchanged, a filter rod containing four 25mm long double Venturi units (100mm×22.0mm×350Pa) can be prepared using a corresponding mold. Using this Venturi rod, the "empty tube section + cooling section" of the fiit cartridge was manually replaced. Both the smoke-generating section and the filter section were connected with large holes, resulting in 10 three-section cigarette samples. Each sample contained one double Venturi unit. The cigarettes were tested according to the national standard for electronic cigarettes, with a single puff duration of 3.0 s, a puff volume of 55.0 mL, a puff frequency of one puff every 30.0 s, and all devices used were MYUZ devices. The heating time was 5 minutes, and the number of puffs was 10. According to the test data, the smoke concentration index (SDI) of the control group was 34.1%, while that of the venturi tube was 44.2%. The stability of the front and rear sections was improved, and the smoke temperature was 47.6℃. The overall experience was better and it could meet the requirements of heated cigarettes.

[0084] Example 8

[0085] Figure 12 This is a cross-sectional view of a three-section traditional cigarette stick according to another embodiment of the present invention. In the figure, 1'”” is the cigarette stick segment, 2'”” is the double Venturi filter rod segment, and 3'”” is the cellulose acetate filter segment.

[0086] In Example 2, by adjusting d1=1.2mm, d4=7.48mm, and L2=13mm, while keeping other parameters unchanged, a Venturi rod 2'”” containing eight 15mm long double Venturi units can be prepared using the corresponding mold, measuring 120mm×23.5mm×300Pa. The cellulose acetate rod 3'”” can be prepared using conventional filter rod methods. By first combining the Venturi rod 2'”” with the cellulose acetate rod 3'””, and then connecting them to a cigarette, a [further details needed for the final product]. Figure 12 The cigarette shown can reduce the temperature of the smoke, reduce irritation, and improve sensory quality.

[0087] A standard cigarette with a circumference of 24.0 mm, a cigarette segment 1"" length of 54 mm, a filter rod length of 30 mm, and a draw resistance of 700 Pa was selected. A 15 mm long double Venturi filter rod 2""" and a 15 mm long cellulose acetate filter rod 3""" were combined, with the draw resistance also set to 700 Pa. This composite rod replaced the original single cellulose acetate filter rod to form a cigarette. Comparison with the original cigarette showed similar smoke analysis results, but the smoke temperature dropped to 42.6℃, irritation decreased, and the overall quality of the cigarette improved.

[0088] This invention features a rational design and unique structure, resulting in a significant smoke cooling effect. It can reduce the number of segments in a cigarette, thus lowering cigarette costs. Because the venturi channel in the middle of the filter rod is a straight-through structure, the amount of smoke can be further adjusted by changing the size of the internal cavity channel. This allows for the production of cigarettes with varying atomization amounts while simultaneously cooling the smoke, satisfying the diverse smoking experiences of different users.

[0089] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A hollow cooling rod with a double Venturi structure, characterized in that, It consists of an inner Venturi channel (4), an outer Venturi channel (5), and a forming paper (6) covering the outer Venturi channel; The inner Venturi channel (4) is formed by multiple inner Venturi cavities (22) that are formed along the axial direction inside the filter rod body (21) after being pressed. The external Venturi channel (5) is a channel formed by the outer wall of the filter rod body (21) and the covering molding paper (6) after the filter rod body (21) is pressed, which is a structure of multiple external Venturi cavities (23) along the axial direction. The external Venturi channel (5) is composed of the outer wall of the body part with axial grooves and a corrugated tube shape along the axial direction and the outer covering molding paper (6). The cross-section of the filter rod body (21) is a grooved arc shape. The difference between the maximum diameter and the minimum diameter of the external Venturi cavity is 0.1-2 mm.

2. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that, The filter rod body (21) has a certain elasticity and strength, with a hardness ≥84% and a minimum wall thickness b ≥0.5mm.

3. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that, The inner Venturi channel (4) is formed by multiple inner Venturi cavities (22) and multiple inner Venturi throat cylindrical tubes (221) interlaced along the axial direction; The cross-section of the inner Venturi cavity (22) is an irregular structure, including any one of polygonal, circular, star-shaped, heart-shaped, plum blossom-shaped, leaf-shaped, or arc-shaped.

4. The hollow cooling rod with a double Venturi structure according to claim 3, characterized in that, The maximum nominal diameter d2 of the inner Venturi cavity (22) is 2mm-6mm, and the cavity length L2 is 5mm-60mm; The nominal diameter d1 of the cavity of the cylindrical tube (221) in the throat of the internal Venturi has a value of ≤2 mm and the length L1 is 0.5 mm-10 mm. The length of the Neventuri cavity (22) is 1 to 50 times the length of the Neventuri throat cylindrical tube (221).

5. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that, The cross-sectional shape of the inner Venturi cavity (22) of the inner Venturi channel (4) and the inner Venturi throat cylindrical tube (221) may be the same or different; the inner Venturi cavity (22) is composed of irregularly shaped curved tubes with gradually increasing and equal diameters and gradually decreasing nominal diameters; the gradual increase and decrease along the axial direction are equal-distance gradual increase and gradual decrease; the inner Venturi cavities (22) with gradually increasing and decreasing nominal diameters are all arc-shaped or conical along the axial direction.

6. The hollow cooling rod with a double Venturi structure according to claim 5, characterized in that, At both ends of the same Venturi cavity unit, the arc and tapered tubes gradually increase and decrease in arc and angle, respectively, with the same and symmetrical angle.

7. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that, The groove depth of the Victoire channel (5) is 0.05mm-1.0mm, and the number of grooves is 1-30.

8. The hollow cooling rod with a double Venturi structure according to claim 7, characterized in that, The number of grooves in the Venturi channel (5) is 1-12, and the 1-12 grooves are evenly distributed along the circumference.

9. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that, The outer Venturi channel (5) has no groove. By increasing the roundness of the filter rod body (21) to 0.35-0.60 mm, a small gap is formed between the filter rod body and the forming paper, thereby forming the throat channel of the outer Venturi and creating a double Venturi structure.

10. The hollow cooling rod with a double Venturi structure according to claim 1 or 2, characterized in that, The inner and outer walls of the inner Venturi channel (4) and the outer Venturi channel (5) are both smooth structures; The material used to form a smooth structure is any one of the following polymer materials: PP, PE, PET, PLA, PC, PS, PA, PCL, PHA, PHB, PBS, PGS, PEA, PPS, ABS, PVC, PBAT, PEEK, PMMA, or it is an injection molded part made of cellulose acetate, or a mixture of cellulose acetate with one or more of PLA fiber, PP fiber, viscose fiber, and polyester fiber, and a curing agent.

11. The hollow cooling rod with a double Venturi structure according to claim 1, characterized in that: There are two methods for preparing double Venturi structure hollow cooling rods: injection molding and wire drawing filter rod forming. The injection molding process involves customizing a corresponding mold based on the designed structure of the double Venturi filter rod, and then using the mold for injection molding. The aforementioned fiber filter rod forming process involves introducing a fiber bundle material that has been loosened and treated with a curing agent such as triacetyl ester or tributyl citrate into a fiber filter rod forming machine. The fiber bundle material is then introduced into a fiber drawing and shaping smoke gun equipped with a corresponding mold, and the hollow rod that has been cured at high temperature and cooled and shaped is drawn out and cut to prepare the filter rod. The fiber bundles are made of cellulose acetate bundles or a mixture of cellulose acetate and polylactic acid fiber bundles. Triacetin or tributyl citrate is applied, and the bundles are introduced into a special smoke gun equipped with a corresponding mold. The bundles are then drawn out and slit after being cured by high temperature with steam and shaped by cold air.

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