Systems and apparatus for steam generation

Abstract

In an exemplary arrangement, a steam generator for use in a medical device may include a heating core in fluid communication with a source of fluid and defining at least one fluid path along which fluid from the source of fluid travels. The at least one fluid path may include one or more surfaces that generate turbulence in the fluid. The steam generator may also include a coil disposed in the heating core, the coil configured to receive an electric current to heat fluid traveling along the at least one fluid path, thereby generating steam.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of priority from U.S. Provisional Application No. 63 / 156,079, filed Mar. 3, 2021, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure generally relates to devices, systems, and methods for generating steam, and more particularly, to a steam generator for a steam ablation device.

Background Art

[0003] Certain medical conditions, such as prostate diseases, can be treated by ablation, including steam ablation. Such ablation or resection can be performed using a device having a sheath that is inserted into a body cavity or other patient's body. Steam (e.g., water vapor) is released from the device to excise or otherwise treat tissue, such as prostate tissue. The steam can be generated by a steam generator of the device. It is desirable for the generator to generate high - quality steam more efficiently with a smaller installation area or footprint than current generators.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The systems, devices, and methods of the present disclosure can correct some of the above - mentioned deficiencies and / or address other aspects of the prior art.

Means for Solving the Problems

[0005] In an exemplary configuration, a steam generator for use in a medical device may include a heating core that is in fluid communication with a fluid source and defines at least one fluid path through which the fluid from the fluid source travels. The at least one fluid path may include one or more surfaces that generate turbulence in the fluid. The steam generator may also include coils positioned around the heating core, which are configured to receive an electric current to heat the fluid traveling along the at least one fluid path, thereby generating steam.

[0006] The coil can be configured to inductively heat the fluid.

[0007] The heating core may include a grid-like body, where one or more columns of the grid-like body can define one or more surfaces that generate turbulence in the fluid.

[0008] The heating core may further include a sheath arranged around a grid-like body.

[0009] The grid-like body may contain Inconel.

[0010] The grid-like body can have a substantially cylindrical shape.

[0011] The grid-like structure can define multiple openings defined by multiple support columns.

[0012] All openings can communicate with each other fluidly.

[0013] At least one fluid path can define multiple fluid movement routes along (a) a passage substantially parallel to the longitudinal axis of the grid-like body and (b) a passage crossing the longitudinal axis of the grid-like body.

[0014] At least a portion of the heating core can be placed inside the needle of the medical device.

[0015] A portion of the needle with a heating core can be placed within a shaft that can be inserted into the body cavity of a subject.

[0016] The heating core may include a tube, which may define a lumen with a textured wall surface. The textured wall surface may generate turbulence in the fluid.

[0017] The tube can form a coil.

[0018] The heating core may contain two or more coils.

[0019] The pipe may have a non-circular cross-section.

[0020] In another exemplary configuration, a steam generator for use in a medical device may include a grid-like body that is in fluid communication with a fluid source and defines multiple fluid paths through which the fluid from the fluid source travels. The grid-like body may include multiple columns that define multiple openings. The steam generator may further include coils arranged around the grid-like body. The coils may be configured to receive an electric current to heat the fluid traveling along the multiple fluid paths, thereby generating steam.

[0021] Multiple fluid paths define fluid movement routes along (a) passages substantially parallel to the longitudinal axis of the grid-like body and (b) passages that cross the longitudinal axis of the grid-like body.

[0022] At least a portion of the grid-like body can be placed inside the needle of a medical device.

[0023] The grid-like body can have a substantially cylindrical shape.

[0024] In a further exemplary arrangement, a steam generator for use in a medical device can include a lattice body that is in fluid communication with a fluid source and defines a plurality of fluid paths through which fluid from the fluid source moves. The plurality of fluid paths can define fluid movement routes along (a) a passage substantially parallel to the longitudinal axis of the lattice body and (b) a passage transverse to the longitudinal axis of the lattice body. The steam generator can further include a coil disposed around the lattice body. The coil can be configured to receive an electric current so as to heat the fluid moving along the plurality of fluid paths, thereby generating steam.

[0025] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention described in the claims. As used herein, the terms “comprises,” “comprising,” or other variations thereof are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example” rather than “ideal.” As used herein, the term “proximal” means in the direction closer to the operator, and the term “distal” means in the direction farther from the operator. Although vapor ablation is referred to herein, such reference should not be construed as limiting. The embodiments disclosed herein may also be used with other types of ablation mechanisms (e.g., cryoablation, RF ablation, or other types of ablation) or other devices not related to ablation.

[0026] The accompanying drawings, which are incorporated herein and constitute a part of this specification, illustrate embodiments of the disclosure and together with the specification serve to explain the principles of the disclosure.

Brief Description of the Drawings

[0027] [Figure 1] It is a side view of a part of an exemplary ablation device. [Figure 2] An exemplary vapor generator for use with the ablation device of FIG. 1 is shown. [Figure 3] An exemplary heating core for use with the vapor generator of FIG. 2 is shown. [Figure 4] An exemplary heating core for use with the vapor generator of FIG. 2 is shown. [Figure 5] An exemplary heating core for use with the vapor generator of FIG. 2 is shown. [Figure 6] An exemplary shaft and distal tip of an ablation device such as the ablation device of FIG. 1 are shown. [Figure 7] An exemplary heating core for use with the shaft and distal tip of FIG. 6 is shown. [Figure 8] An exemplary heating core for use with the shaft and distal tip of FIG. 6 is shown. [Figure 9] An exemplary heating core for use with the shaft and distal tip of FIG. 6 is shown. [Figure 10] An exemplary heating core for use with the shaft and distal tip of FIG. 6 is shown. [Figure 11] An exemplary vapor generator for use with an ablation device such as the ablation device of FIG. 1 is shown. [Figure 12] An exemplary tube for use with, for example, a fluid coil is shown. [Figure 13] An exemplary fluid coil is shown. [Figure 14] An exemplary fluid coil is shown.

Mode for Carrying Out the Invention

[0028] A steam generator for a steam ablation apparatus may include a high-frequency ("RF") coil surrounding a conductor that defines a path through which a fluid (e.g., water) can pass. The conductor can be formed by additive manufacturing methods such as three-dimensional ("3D") metal printing. The current passing through the RF coil generates an electromagnetic flux, which causes an electric current (such as an eddy current) in the conductor, resulting in heating of the conductor. The heating of the conductor causes the water passing through it to heat, thereby generating steam. The conductor can include, for example, a conductive mesh, a grid, or one or more coils. The generator (RF coil and conductor) can be located within the handle of the steam ablation apparatus or within the shaft of the steam ablation apparatus. The steam can be delivered to the treatment site to therapeutically treat the tissue. For example, the steam excises or ablates the tissue. As an example, the tissue to be excised is prostate tissue, which can be used to treat benign prostatic hyperplasia (BPH).

[0029] Figure 1 shows a side view of an exemplary distal assembly of the ablation device 10. The ablation device 10 may include a handle 50 and a shaft 11. The shaft 11 can be inserted into the patient's body cavity, or otherwise into the patient's body (e.g., through the patient's tissue, such as via a transperineal route). The shaft 11 may have a distal tip 12. The handle 50 may be configured to be grasped by the user.

[0030] The needle 24 may be extendable and / or retractable from the distal tip 12. The needle 24 may be a member having a central lumen or channel extending from the proximal end toward the distal tip of the needle 24, and a plurality of openings near the distal tip of the needle 24. The plurality of openings may be configured to transmit the contents of the central lumen or channel (e.g., steam) to the surrounding tissue into which the needle 24 is positioned, received, or otherwise inserted. For example, the central lumen or channel of the needle 24 may be configured to receive steam into it (e.g., via a steam generator) and to supply steam to the tissue through the openings. The needle 24 may also be configured to have a first insertion configuration in which the needle 24 is housed, received, or otherwise positioned within the shaft 11 (e.g., no portion of the needle 24 extends radially outward from the distal tip 12 with respect to the longitudinal axis of the distal tip 12). The needle 24 may have a second treatment configuration (Figure 1), in which the needle 24 extends from the distal tip 12 (for example, beyond the distal tip 12 distally with respect to the longitudinal axis of the distal tip 12 and / or radially outward from the distal tip 12). In the treatment configuration, the needle 24 may be curved radially outward with respect to the longitudinal axis of the shaft 11.

[0031] The handle 50 may include a cable 52 extending proximal from the proximal end of the handle 50. The cable 52 can transmit power, fluid, signals, etc., to the handle 50 or to other parts of the ablation device 10 (e.g., the shaft 11). In one example, the cable 52 can transmit a fluid, such as water, from a fluid source to the ablation device 10. In some embodiments, a steam generator (described in further detail with respect to Figures 2 to 14 herein) may be located inside the ablation device 10 (e.g., inside the handle 50 or the shaft 11). The fluid passed through the steam generator may be contained within the ablation device 10 or transmitted to the ablation device 10 via the cable 52. In other embodiments, the steam generator may be located outside the ablation device 10, and steam may be transmitted from the steam generator to the ablation device 10 via the cable 10.

[0032] Figure 2 shows an exemplary steam generator 160. The steam generator 160 may be used to supply steam to a device such as the ablation device 10. In this example, the steam generator 160 may be located inside the handle 50 or inside the shaft 11. In other examples, the steam generator 160 may be located outside the ablation device 10, as described above. The steam generator 160 may include a coil 162 and a heating core 170. The current passing through the coil 162 helps to heat the fluid moving through the core 170, as will be described in more detail below. The steam generator 160 helps to inductively heat the fluid.

[0033] The coil 162 can carry an RF current or other alternating current. The coil 162 may have any features that assist the coil 162 in carrying current. The coil 162 may be made of any suitable material and may include any suitable number of windings. For example, the coil 162 may include Litz wire (a type of wire particularly efficient for transmitting RF energy). When an alternating current passes through the coil 162, the current can generate one or more magnetic fields. The coil 162 may consist of windings. Alternatively, the coil 162 may be formed by additive manufacturing methods, including, for example, extrusion, binder injection, powder bed melting, or any other suitable form of additive manufacturing / 3D metal printing. The coil 162 may include insulating material to prevent current from the coil 162 from passing through other structures or between the turns of the coil 162.

[0034] The core 170 may include a grid-like body 172 and a sheath 174. The grid-like body 172 may have a substantially cylindrical overall shape having a first end 176 and a second end 178. The grid-like body may include a plurality of cells having a plurality of posts intersecting at a plurality of nodes. The grid-like body 172 may include a single cell structure repeated multiple times in a pattern, or a plurality of cell structures that may be repeated in a pattern. Each cell may include an opening defined by a post. All of the openings of the plurality of cells can be in fluid communication with each other. Fluid can flow from the first end 176 to the second end 178 through the fluid-communicated openings. Alternatively, the openings may define a plurality of paths that extend from the first end 176 to the second end 178 but are not in fluid communication with each other between the first end 176 and the second end 178. The grid-like body 172 may be formed of one or more conductive materials and may be formed by any of the additive manufacturing techniques described above. For example, the lattice body 172 may be formed from a printable material exhibiting high thermal conductivity, such as copper. Alternatively, the lattice body 172 may be formed from a printable material exhibiting a combination of high thermal conductivity and biocompatibility, such as 17-4 stainless steel, Inconel, 316L stainless steel, or cobalt-chromium (CoCr). The material of the lattice body 172 may be uniform or varied to maximize the energy transfer efficiency described below. In some configurations, the material of the lattice body 172 may be formed via powder bed melting.

[0035] The sheath 174 can enclose the outer surface of the grid body 172 between the first end 176 and the second end 178, preventing fluid from leaking out from the sides of the grid body 172 between the first end 176 and the second end 178. The sheath 174 can be formed from any suitable material, such as metal or nonmetal. The sheath 174 can be formed from a sheet of material or by any suitable manufacturing method, such as additive manufacturing. The sheath 174 may be formed from the same material as the grid body 172 or from a different material. The sheath 174 can be fixed to the grid body 172, for example, by adhesive, welding, or friction fitting. Together, the sheath 174 and the grid body 172 can form a tube (sheath 174) having a grid infill or filler (grid body 172).

[0036] The core 170 may be positioned at the center of the coil 162. As shown in Figure 2, the core 170 may be separated from the coil 162 by a gap. Alternatively, the coil 162 may be in contact with the core 170, but may be insulated so that current does not flow from the coil 162 to the core 170, and the insulation may have properties that allow the core 170 to withstand heating. When current (e.g., RF current) passes through the coil 162, the coil 162 can generate one or more magnetic fields. The magnetic fields can induce eddy currents within the conductive material of the grid body 172. Eddy currents flowing through the resistance of the conductive material can generate heat within the grid body 172. Multiple supports of the grid body 172 can be configured to provide a desired heating pattern. For example, more heat may be generated in one part of the grid body 172 than in other parts of the grid body. In one example, more heat may be generated in the radially outer part of the grid body 172 than in the radially inner part of the grid body 172 (with respect to the longitudinal axis of the core 170). To generate high-quality, consistent steam throughout the grid body 172, more heat may be generated in parts of the grid body where additional heat is required. The material of the grid body 172 can be selected to facilitate the desired heating pattern. Alternatively, the multiple columns of the grid body 172 may be configured to heat evenly. For example, the thickness of the columns may be selected to promote even heating. Eddy currents can also be generated in the sheath 174 to heat the sheath 174.

[0037] When current flows through coil 162, a fluid source (e.g., water) can supply fluid to the first end 176 of the grid body 172. The grid body 172 can define fluid paths to which the fluid from the fluid source can travel. The fluid paths may include numerous branches, and the specific routes the fluid follows may vary. For example, routes may facilitate the movement of fluid substantially parallel to the longitudinal axis of the grid body 172 and across the longitudinal axis of the grid body 172. As the fluid passes through the columns and / or sheath 174 of the grid body 172, heat is transferred from the grid body 172 and / or sheath 174 to the fluid, thereby heating the fluid. The flow through the grid body 172 can be turbulent, providing a large surface area to contact the fluid and heat it. Turbulence can facilitate efficient heat flow. The fluid can be heated sufficiently to produce steam. For example, substantially all of the fluid can be converted into steam. The configuration of the grid-like body 172 provides a large surface area in contact with the fluid, resulting in efficient heating. Compared to a coil through which fluid flows to be heated, the grid-like body 172 provides the same heating (due to the large surface area of ​​the grid-like body 172 in contact with the fluid) while occupying a smaller footprint. The smaller footprint can facilitate manufacturing efficiency and / or a smaller size of the ablation device 10. For example, the steam generator 160 can occupy a smaller space within the handle 50 of the ablation device 10, allowing the handle 50 to be manufactured in a smaller size, creating space for additional components (e.g., control boards or other electronic equipment), allowing for an alternative location for the steam generator 160 within the handle 50, or facilitating the manufacturing of the handle 50 due to greater space availability. Furthermore, as stated above, a smaller external shape or profile of the steam generator 160 may allow the generator 160 to be placed within the shaft 11.

[0038] Compared to a coil, for example, the length of the fluid passage can be shorter through the grid-like body 172, providing faster movement through the steam generator 160, thereby resulting in more efficient heat transfer. That is, the total length of the fluid passage through the grid may be shorter than the total length of the fluid passage around the various turns of a coil. Efficient heat transfer from the core 170 to the fluid produces high-quality, uniform steam. The quality of the steam is the ratio of water to steam in the mixture. For example, the mixture starts with 100% water and 0% steam. However, when heat is applied, a phase change occurs and the proportion of steam increases. Eventually, all the water is converted into steam, and the mixture becomes 0% water and 100% steam. Since steam is a gas and can pass through the interstitial space in tissue more easily (e.g., more freely) than a liquid, the higher the quality of the steam (e.g., the higher the ratio), the more ideal it is for treating tissue (e.g., prostate tissue).

[0039] The steam generator 160 may have additional elements not shown in Figure 2. For example, thermocouples may be coupled to a part of the core 170, such as a grid-like body 172, to enable heating control of the core 170.

[0040] Figures 3A to 5C show exemplary cores 370, 470, and 570. Cores 370, 470, and 570 can have any of the characteristics of core 170 described above. Each of cores 370, 470, and 570 can have a grid body 372, 472, and 572, respectively, and a sheath 374, 474, and 574, respectively. The grid bodies 372, 472, and 572 can have any of the characteristics of grid body 172, and the sheaths 374, 474, and 574 can have any of the characteristics of sheath 174. Figures 3A / 3B, 4A / 4B, and 5A / 5B show only the grid bodies 372, 472, and 572, respectively. Figures 3A, 4A, and 5A show cross-sectional views, and Figures 3B, 4B, and 5B show perspective views. Figures 3C, 4C, and 5C show cores 370, 470, and 570, including sheaths 374, 474, and 574, respectively. Cores 370, 470, and 570 may be identical except that the grid bodies 372, 472, and 572 may have different grid / cell patterns. For example, each of the grid bodies 372, 472, and 572 may have a varying grid / cell pattern selected to balance the surface area, cell size, back pressure, and thermal conductivity between the coil 162 and each grid body 372, 472, and 572.

[0041] The grid-like bodies 372, 472, and 572 are described individually below, but it will be understood that the characteristics described below can be combined with each other in any combination. The shapes and structures may be mixed and matched to generate a wide variety of patterns. The patterns of the grid-like bodies 372, 472, and 572 below are merely examples. A wide variety of structures / patterns can be used within the scope of this disclosure.

[0042] As shown in Figures 3A and 3B, the cross-sectional layered grid body 372 of the core 370 may include cloverleaf / rounded "X" shaped supports. In one embodiment, this same pattern may be repeated in layers along the length of the grid body 372. The layers may be interconnected via supports that extend at least partially along the longitudinal axis of the grid body 372, so that the grid body 372 is a single piece. As shown in Figures 3A and 3B, the layers having cloverleaf / rounded "X" shapes may be offset / rotated relative to one another. The cross-sectional slices of the grid body 372 are not uniform, and not all cross-sections may contain cloverleaf / rounded "X" shapes. For example, a particular cross-sectional slice may contain only supports that connect cloverleaf / rounded "X" shaped supports but are not themselves cloverleaf / rounded "X" shaped. In one example, alternating layers may be used, in which case the cloverleaf / rounded "X" shaped supports are offset from each other between layers (for example, so that the cloverleaf / rounded "X" shapes are shifted in a direction parallel to the cloverleaf / rounded "X" shaped arms). The layers may be repeated in a pattern across the entire thickness of the grid body 372 (for example, every other layer may be the same). Alternatively, layers of other patterns may be used. Furthermore, the layers may alternatively have supports of different shapes from each other.

[0043] The spaces between the clover / rounded "X" shaped supports and the supports connecting the various layers can form openings through which fluid can pass. All openings may be fluid-communicated with each other. Thus, water or another fluid can pass from the first end of the grid body 372 to the second end of the grid body 372. The fluid can also pass through the grid body 372 laterally (perpendicular to the longitudinal axis of the grid body 372). As the fluid moves through the grid body 372, it can traverse various passages while in contact with the supports of the grid body 372. As described above, the supports of the grid body 372 can heat the fluid.

[0044] Figures 4A to 4C show alternative grid-like bodies 472. As described above with respect to grid-like bodies 372, grid-like bodies 472 may include multiple layers stacked on top of each other along the longitudinal axis of grid-like bodies 472. In particular, as shown in the cross-sectional view of Figure 4A, the layers of grid-like bodies 472 may include struts in a substantially grid-like or grid pattern. The struts define multiple openings, which may be rounded, rounded squares, or alternative shapes. Struts may extend longitudinally from the grid-like pattern (for example, partway along a strut defining one side of one of the multiple openings) to join multiple layers together. The struts connecting the layers may leave openings through the grid-like bodies 472 in a transverse direction perpendicular to the longitudinal axis of grid-like bodies 472. All openings in the grid-like bodies 472 can be fluidly connected to each other.

[0045] The layers of the grid body 472 may all be the same and have the same orientation such that their openings align with each other along the longitudinal axis of the grid body 472. Alternatively, the layers of the grid body 472 may be offset from each other so that their openings do not align. For example, the layers of the grid body 472 may be rotated relative to each other or offset laterally from each other. The layers of the grid body 472 (and / or other grid bodies described herein) may be angled such that the planes defined by the layers are not perpendicular to the longitudinal axis. The layers may have different angles to each other or the same angle.

[0046] As described above with respect to the grid-like body 372, the fluid can flow longitudinally throughout the grid-like body 472. As the fluid moves longitudinally throughout from the first end to the second end of the grid-like body 472, it can move longitudinally and laterally to take various paths. The columns of the grid-like body 472 can be heated, as described above in relation to Figure 2. The heated columns can transfer heat to the fluid, causing it to vaporize.

[0047] Figures 5A to 5C show alternative grid-like bodies 572. The grid-like bodies 572 may have a substantially fishnet pattern. The openings of the grid-like bodies 572 may be oval or fisheye-shaped. Alternatively, the openings may have a rounded shape, square, rhombus, triangular, sector, or any other suitable shape. All the openings may be the same shape or they may be different shapes from one another.

[0048] The grid-like bodies 372 and 472 may have a non-uniform cross-section (discrete columns can connect layers to one another), while the grid-like body 572 may have a uniform cross-section. The patterns shown in Figures 5A to 5C may extend along the entire length of the grid-like body 572. The grid-like body 572 can define a plurality of channels extending longitudinally through it. The channels may be discrete (not fluidly connected to one another) or fluidly connected. For example, openings may be periodically formed in the grid-like body between the channels.

[0049] As described above with respect to the grid-like bodies 372 and 472, the fluid can generally flow longitudinally through the grid-like body 572. If the channels are discrete, the fluid can be retained within individual channels. If the channels are fluid-connected, the fluid can move longitudinally and laterally as it moves longitudinally as a whole from the first end of the grid-like body 572 to the second end of the grid-like body 572, and can take various paths. The columns of the grid-like body 572 may be heated, as described above in relation to Figure 2. Heated columns can transfer heat to the fluid, causing it to vaporize.

[0050] Figure 6 shows an exemplary shaft 611 of the steam ablation apparatus 610. The steam ablation apparatus 610 may have any features of the steam ablation apparatus 10, and the shaft 611 may have any features of the shaft 11. The shaft 611 may be terminated at a distal tip 612 (having any features of the distal tip 12). A needle 624 (having any features of the needle 24) may extend through the lumen of the shaft 611. A steam generator 660 (having any features of the steam generator 160 described above) may be positioned relative to the needle 624. That is, in such a configuration, the needle 624 itself may be formed of Inconel or other similar metal / material and function as part of the steam generator 660. In other words, the length of the needle 624 may be surrounded (e.g., wrapped) by a part of the steam generator (e.g., an RF coil similar to the RF coil 162). As described above with respect to needle 24, a portion of needle 624 may be extendable and retractable relative to shaft 611, so that needle 624 can selectively extend outward from shaft 611. The distal tip of needle 624 may be bendable to facilitate the radially outward extension of needle 624 relative to shaft 611.

[0051] A portion of the needle 624 proximal to the bendable portion (e.g., about 6 inches of the needle 624) may include (or form) at least a portion of a steam generator 660, which may be made of any suitable material (e.g., Inconel). Including the steam generator 660 at least partially within (or as part of) the needle 624 allows for the provision of very pure steam for delivery to the tissue, as such a position minimizes the distance between the steam generator and the target tissue, thereby minimizing condensation that may occur along the steam delivery passage. As described above, the steam supplied from the steam generator 660 may have a smaller travel distance compared to other positions of the steam generator. Such positioning of the steam generator 660 within (or as part of) the needle 624 may reduce or eliminate the need to cool the outer jacket of the needle 624. For example, in contrast to an arrangement where the steam generator is located elsewhere, such as on the handle, thereby requiring control over the temperature of the handle and the entire shaft to prevent it from exceeding an acceptable temperature threshold for handling, locating the steam generator 660 along the distal end of the shaft 611 (either inside or as part of the needle 624) allows for cooling of only that portion of the shaft 611.

[0052] In one example, the sheath of the needle 624 may surround the steam generator 660. In another example, the generator 660 may form the outer surface of the needle 624. The steam generator 660 may include a coil 162, as described above with respect to Figure 2. Some parts of the generator 660 (e.g., the coil 162) may be arranged outside the needle 624 (e.g., surrounding it radially), while the core (having any of the characteristics of cores 170, 370, 470, and 570) may be arranged inside the needle 624.

[0053] Figures 7A to 10C show exemplary cores 770, 870, 970, and 1070 for use with steam generator 660. These exemplary cores may also be used with steam generator 160. Cores 770, 870, 970, and 1070 can have any of the features of the cores 170, 370, 470, and 570 described above. Each of the cores 770, 870, 970, and 1070 may have a grid-like body 772, 872, 972, and 1072, and a sheath 774, 874, 974, and 1074, respectively. The grid-like bodies 772, 872, 972, and 1072 can have any of the characteristics of the grid-like bodies 172, 372, 472, and 572, and the sheaths 774, 874, 974, and 1074 can have any of the characteristics of the sheaths 174, 374, 474, and 574. Figures 7A / 7B, 8A / 8B, 9A / 9B, and 10A / 10B show only the grid-like bodies 772, 872, 972, and 1072, respectively. Figures 7A, 8A, 9A, and 10A show cross-sectional views, and Figures 7B, 8B, 9B, and 10B show perspective views. Figures 7C, 8C, 9C, and 10C show cores 770, 870, 970, and 1070, including sheaths 774, 874, 974, and 1074, respectively. Cores 770, 870, 970, and 1070 may be identical except that the grid bodies 772, 872, 972, and 1072 may have different grid / cell patterns. For example, each of the grid bodies 772, 872, 972, and 1072 may have a varying grid / cell pattern selected to balance surface area, cell size, back pressure, and thermal conductivity between the coil 162 and each grid body 772, 872, 972, and 1072. The grid patterns shown in Figures 7A to 10C are for illustrative purposes only. Alternative grid patterns may be used, including those of grid bodies 372, 472, and 572. The properties of the grid-like bodies disclosed herein may be combined in any way, and the features of the grid-like bodies may be mixed and combined.

[0054] Figures 7A–7C show exemplary grid bodies 772. As described above with respect to grid bodies 372, 472, and 572, a grid body 772 may include multiple layers stacked on top of each other along the longitudinal axis of the grid body 772. As particularly shown in the cross-sectional view of Figure 7A, the layers of the grid body 772 may include posts defining square or rectangular cutouts / openings arranged in rows and columns. The layers may be joined at joints 773 on the outer surface of the grid body 772. For example, the layers may be joined together at two, three, four, or more joints. Posts 775 may extend between layers (e.g., midway between the vertices of four adjacent square / rectangular openings) to join multiple layers together. Alternatively, posts 775 may be omitted. Posts connecting the layers may leave openings through the grid body 772 in the transverse direction perpendicular to the longitudinal axis of the grid body 772. All of the openings in the grid-like body 772 can communicate with each other through fluids.

[0055] The layers of the grid body 772 may all be the same and have the same orientation such that their openings align with each other along the longitudinal axis of the grid body 772. Alternatively, the layers of the grid body 772 may be offset from each other so that their openings do not align. For example, the layers of the grid body 772 may be rotated relative to each other or offset laterally from each other. The layers of the grid body 772 (and / or other grid bodies described herein) may be angled such that the planes defined by the layers are not perpendicular to the longitudinal axis. The layers may have different angles to each other or the same angle.

[0056] As described above in relation to the grid-like bodies 372, 472, and 572, the fluid can flow longitudinally throughout the grid-like body 772. As the fluid moves longitudinally throughout from the first end of the grid-like body 772 to the second end of the grid-like body 772, it can move longitudinally and laterally to take various paths. The columns of the grid-like body 772 can be heated as described above in relation to Figure 2. The heated columns can transfer heat to the fluid, causing it to vaporize.

[0057] Figures 8A to 8C show exemplary grid bodies 872. As described above with respect to grid bodies 372, 472, 572, and 772, a grid body 872 may include multiple layers stacked on top of each other along the longitudinal axis of the grid body 872. As particularly shown in the cross-sectional view of Figure 8A, the layers of the grid body 872 may include posts defining circular openings / cutouts arranged in rows and columns. Posts 875 may extend between layers to join multiple layers together. Posts 875 connecting the layers may leave openings through the grid body 872 in a transverse direction perpendicular to the longitudinal axis of the grid body 872. For example, as shown in Figure 8B, circular openings may be formed to allow the transverse passage of water (for example, a grid body 872 may have circular openings defining a plane parallel to the longitudinal axis of the grid body 872). All openings in the grid body 872 can be in fluid communication with each other.

[0058] The layers of the grid body 872 may all be identical and oriented in the same direction so that their openings align with each other along the longitudinal axis of the grid body 872. Alternatively, the layers of the grid body 872 may be offset from each other so that their openings do not align. For example, the layers of the grid body 872 may be rotated relative to each other or offset laterally from each other. The layers of the grid body 872 (and / or other grid bodies described herein) may be angled such that the planes defined by the layers are not perpendicular to the longitudinal axis. The layers may have different angles to each other or the same angle.

[0059] As described above with respect to the grid-like bodies 372, 472, 572, and 772, the fluid can flow longitudinally throughout the grid-like body 872. As the fluid moves longitudinally throughout the grid-like body 872 from the first end to the second end, it can move longitudinally and laterally to take various paths. The columns of the grid-like body 872 can be heated, as described above in relation to Figure 2. The heated columns can transfer heat to the fluid, causing it to vaporize.

[0060] Figures 9A to 9C show exemplary grid-like bodies 972. As described above with respect to grid-like bodies 372, 472, 572, 772, and 872, the grid-like body 972 may include multiple layers stacked on top of each other along the longitudinal axis of the grid-like body 972. As particularly shown in the cross-sectional view of Figure 9A, the layers of the grid-like body 972 may include struts that define rows of hexagonal openings / cutouts. The struts may have a honeycomb pattern. The struts may extend between struts of layers to join multiple layers together. The longitudinal struts may extend between layers parallel to the longitudinal axis of the grid-like body 972 so that the hexagonal openings can be aligned with each other without obstruction. The struts connecting the layers may leave openings through the grid-like body 972 in the transverse direction perpendicular to the longitudinal axis of the grid-like body 972. All openings in the grid-like body 972 can be in fluid communication with each other.

[0061] The layers of the grid body 972 may all be the same and oriented such that their openings align with each other along the longitudinal axis of the grid body 972. Alternatively, the layers of the grid body 972 may be offset from each other so that their openings do not align. For example, the layers of the grid body 972 may be rotated relative to each other or offset laterally from each other. The layers of the grid body 972 (and / or other grid bodies described herein) may be angled such that the planes defined by the layers are not perpendicular to the longitudinal axis. The layers may have different angles to each other or the same angle.

[0062] As described above with respect to the grid-like bodies 372, 472, 572, 772, and 872, the fluid can flow longitudinally throughout the grid-like body 972. As the fluid moves longitudinally throughout the grid-like body 972 from the first end to the second end, it can move longitudinally and laterally to take various paths. The columns of the grid-like body 972 can be heated, as described above in relation to Figure 2. The heated columns can transfer heat to the fluid, causing it to vaporize.

[0063] Figures 10A to 10C show exemplary grid-like bodies 1072. The grid-like bodies 1072 may have woven, knitted, or crocheted patterns. The supports allow longitudinal and transverse fluid flow through the grid-like bodies 1072 and can generate turbulence within the fluid. As particularly shown in the cross-sectional view of Figure 10A, the layers of the grid-like bodies 1072 may include supports defining rows of parallelogram-shaped openings / cutouts. All of the openings in the grid-like bodies 1072 may be in fluid communication with each other, or only a subset of the openings may be in fluid communication with each other.

[0064] As described above with respect to the grid-like bodies 372, 472, 572, 772, 872, and 972, the fluid can flow longitudinally throughout the grid-like body 1072. As the fluid moves longitudinally throughout from the first end of the grid-like body 1072 to the second end of the grid-like body 1072, it can move longitudinally and laterally to take various paths. The columns of the grid-like body 1072 can be heated as described above in relation to Figure 2. The heated columns can transfer heat to the fluid, causing it to vaporize.

[0065] Figure 11 shows an alternative steam generator 1160. The steam generator may have any characteristics of steam generators 160 or 660, except as described herein. Steam generator 1160 may include an RF coil 1162, which may have any characteristics of RF coil 162. Steam generator 1160 may have a heating core 1180, which may include one or more coils. In one example, the heating core 1170 may include a plurality of fluid coils, including a first fluid coil 1182 and a second fluid coil 1184. As shown, the second fluid coil 1184 may be positioned radially within the first fluid coil 1182, such that the first and second fluid coils 1182, 1184 are arranged concentrically. The heating core 1180 may include an alternative number of coils (e.g., three or more coils) that can be arranged concentrically with one another.

[0066] The fluid coils 1182 and 1184 can define one or more fluid paths through which fluid from a fluid source can move. Fluid coil 1182 may be sealed by a sheath 1164 that can insulate fluid coils 1182 and 1184 from RF coil 1162, or vice versa. Thus, the sheath 1164 can be formed of a high-temperature thermoplastic such as polyimide. The sheath 1164 can be insulating to prevent a direct flow of current from RF coil 1162 to fluid coils 1182 and / or 1184. RF coil 1162 can heat fluid coils 1182 and 1184, as described above with respect to RF coil 162 of steam generator 160.

[0067] As described above, the first fluid coil 1182 and the second fluid coil 1184 can be arranged concentrically. For example, the second fluid coil 1184 can be placed inside the first fluid coil 1182. The first lumen 1183 can extend through the first fluid coil 1182, and the second lumen 1183 can extend through the second fluid coil 1184. The first lumen 1183 and the second lumen 1185 may be in fluid communication with each other. The fluid can pass through the first lumen 1183 and the second lumen 1185 during heating. The fluid may first pass through one of the fluid coils 1182, 1184, and then through the other of the fluid coils 1182, 1184. For example, a fluid source may supply fluid to one end of the fluid coils 1182, 1184. The fluid can move through the lumen 1183 or 1185 to the other end of one of the fluid coils 1182, 1184. The fluid can then enter the other lumen 1183 or 1185 of the fluid coils 1182, 1184 and flow through the lumen 1183 or 1185 until it reaches the other end of the fluid coils 1182, 1184. The lumen 1183, 1185 may be directly joined so that the fluid enters and exits the same end of the steam generator 1160. Alternatively, a component of the tubing (not shown) may span the lumen 1183 and 1185. In such a configuration, the fluid either flows into one end of the steam generator 1160 and out the other end, or flows into the same end of the steam generator 1160 and out the same end. It is understood that the fluid coils 1182 and 1184 can be formed via 3D printing so that numerous configurations of coils 1182 and 1184 can be realized. For example, in some configurations, multiple independent fluid paths may be formed, or a single continuous winding path may be formed. In some configurations, the fluid coil can start from one end, be wound upward in a circular motion toward a second end, then fold itself (e.g., invert, rotate) to form an inner coil, and be wound backward toward the first end.In an alternative configuration, the first coil layer of the fluid coil can be wound in a first direction (e.g., clockwise) to form an outer segment of circular or semicircular shape, then folded back toward the center of the segment and wound in a second direction (e.g., counterclockwise) to form an inner coil segment. This pattern can be repeated to form a number of layers along the longitudinal direction.

[0068] The fluid coils 1182 and 1184 can be formed from any suitable material, such as Inconel. The fluid coils 1182 and 1184 may be formed from the same material or from different materials. Alternatively, the material may differ along a single coil. The wall thickness of the fluid coils 1182 and 1184 may be uniform or varied to provide a desired heating profile. The fluid coils 1182 and / or 1184 may be formed by winding a tube. Alternatively, the fluid coils 1182 and / or 1184 may be formed by additive manufacturing methods, including any of the techniques described above with respect to the steam generator 160.

[0069] Generator 1160 can offer advantages over generators that use only one fluid coil. Generator 1160, with its concentric coils, can provide the same fluid movement length within a smaller footprint. A smaller footprint can have any of the advantages mentioned above with respect to generator 160. In fact, generator 1160 can double or otherwise increase the length of the heating path, thereby increasing the time the fluid is present in the heating coil, and thus producing higher quality steam than existing generators.

[0070] Figures 12A–12D show exemplary tubes having a textured inner surface. The tubes can be used to form coils or other structures for use in generators such as steam generator 1160, or any other steam generators. The tubes can define one or more fluid paths for the fluid flow from a fluid source to traverse. The textured surfaces of the tubes in Figures 12A–12D can provide a higher surface area for efficient energy transfer in steam generators such as steam generator 1160. The textured surfaces can increase fluid turbulence and further promote efficient heating. The tubes in Figures 12A–12D may also be used in conjunction with other steam generators, including generators that use only a single coil to carry the fluid. The textured surfaces can be selected to maximize their surface area while promoting turbulence. The tubes shown in Figures 12A–12D can be formed from any suitable material, such as Inconel, by any suitable method, such as any additive manufacturing techniques described herein. The tubes may be formed from the same material or from different materials. The materials may differ within a single tube.

[0071] Figure 12A shows a first pipe 1280. As shown in Figure 12A, at least one cross section of the pipe 1280 may include a plurality of dimples 1288. The dimples 1288 may be cross sections of channels extending along the inner surface 1286 of the pipe 1280. The dimples 1288 may have a substantially rounded cross section, since at least some of the channels may have rounded bottoms. The channels may extend annularly around the inner surface 1286 and / or along the longitudinal direction of the pipe 1280. The channels may have a uniform width and / or a variable width. The channels may form a rhombic and / or triangular shape on the inner surface 1286. For example, several channels may extend annularly around the inner surface 1286 of the pipe 1280, parallel to each other. Other channels may extend spirally around the inner surface 1286 of the tube 1280, or diagonally along the inner surface 1286, thereby forming annular channels and triangles. The texture or structure of the inner surface 1286 can induce turbulence in the fluid and provide a larger surface area for contact with the fluid than a smooth inner surface. Thus, the texture of the inner surface 1286 can promote improved fluid heating and improved steam generation.

[0072] Figure 12B shows an exemplary tube 1380 having an inner surface 1386. In cross-section, the wall of tube 1380 may have larger dimples 1388 and smaller dimples 1390, each of which may have a rounded shape. The larger dimples 1388 may be portions of larger recesses formed in the inner surface 1386. The smaller dimples 1390 may be portions of smaller recesses formed in the inner surface 1386. The recesses of the inner surface 1386 may have various sizes and profiles. For example, the recesses may form a fish-scale type pattern or any suitable type of pattern. The texture of the inner surface 1386 may induce turbulence in the fluid and provide a larger surface area for contact with the fluid than a smooth inner surface. Thus, the texture of the inner surface 1386 may promote improved fluid heating and improved steam generation.

[0073] Figure 12C shows an exemplary tube 1480 having an inner surface 1486. ​​In cross-section, the walls of tube 1480 may have flat surfaces separated by corners or horns, such as the eight flat surfaces and eight corners shown in Figure 12C. The corners may be cross-sections of channels extending along the inner surface 1486 of tube 1480. The channels may extend annularly around the inner surface 1486 and / or along the longitudinal direction of tube 1480. The channels may have a uniform width and / or a variable width. The channels may form rhombic and / or triangular shapes in the inner surface 1486. ​​For example, some channels may extend annularly around the inner surface 1486 of tube 1480, parallel to each other. Other channels may extend spirally around the inner surface 1486 of tube 1480, or obliquely along the inner surface 1486, thereby forming annular channels and triangles. The texture or structure of the inner surface 1486 can induce turbulence in the fluid and provide a larger surface area for contact with the fluid than a smooth inner surface. Therefore, the texture of the inner surface 1486 can promote improved fluid heating and improved steam generation.

[0074] Figure 12D shows an exemplary tube 1580 having an inner surface 1586. In cross-section, the wall of the tube 1580 may have dimples 1588, each of which may have multiple segments (e.g., rounded segments or straight segments). The dimples 1588 may be cross-sections of recesses formed in the inner surface 1586. The recesses in the inner surface 1586 may have various sizes and profiles, including various depths and cross-sectional sizes. The texture or structure of the inner surface 1586 can induce turbulence in the fluid and provide a larger surface area for contact with the fluid than a smooth inner surface. Thus, the texture of the inner surface 1586 can promote improved fluid heating and improved steam generation.

[0075] Figure 13 shows an exemplary coil 1680 that may be used in a generator such as generator 1160, or in other generators that use coils to carry fluid for heating. The coil 1680 can define a fluid path through which fluid from a fluid source can travel. Features of coil 1680 may be used in conjunction with features of Figures 12A–12D. As shown in Figure 13, the wall 1692 of coil 1680 may have an elongated shape, thereby defining a lumen with an elongated cross-section. For example, as shown in Figure 13, the wall may have an elliptical shape, thereby defining an elliptical opening. In other examples, the wall may have a racetrack shape, rectangular, oval, elliptical, or other suitable shape to define a lumen with an elongated cross-section. The shape of the lumen of coil 1680 may provide more efficient heating of the fluid passing through it. Reducing the distance from the wall 1692 of the coil 1680 to the center of the lumen (along the minor axis of the cross-section of the coil 1680) can provide better heat conduction to the fluid moving through it. For example, the steam formed by heating the fluid passing through it can be less humid compared to the steam produced by a coil having a round cross-section. The coil 1680 can be formed from any suitable material such as Inconel by any suitable method such as any additive manufacturing technique described herein. The material of the coil 1680 may be uniform or non-uniform to provide efficient heating. The width of the wall 1692 may be uniform or varied to efficiently heat the fluid passing through the lumen of the coil 1680.

[0076] Figure 14 shows an exemplary coil 1780 that may be used in a generator such as generator 1160, or in other generators that use coils to carry fluid for heating. The coil 1780 can define a fluid path through which fluid from a fluid source can travel. The features of coil 1780 may be used in conjunction with the features of Figures 12A–12D and Figure 13. As shown in Figure 13, the wall 1792 of coil 1780 can define a lumen 1794 having any suitable cross-sectional shape and size. For example, as shown in Figure 14, the wall 1792 can define a lumen 1794 having a circular cross-sectional shape. In a typical coil with a wall having a circular cross-section, a roughly triangular gap may be formed between the windings. In coil 1780 of Figure 14, the infill 1796 can fill the gap that would otherwise exist in the inner diameter of coil 1780. The infill 1798 can fill the gap that would otherwise exist in the outer diameter of coil 1780. Only one of the infills 1796 / 1798 may be used so that only the inner diameter or only the outer diameter has the infill. Alternatively, both infills 1796 / 1798 may be used. Infills 1796 and 1798 may fill only a portion of the gap or fill all of the gap. For example, as shown in Figure 14, infill 1796 can form a smooth, straight inner diameter of the coil 1780, and infill 1798 can form a smooth, straight outer diameter of the coil 1780. Infills 1796 and / or 1798 may be formed of a uniform material together with walls 1792 so that the coil 1780 forms a cylinder having a helical lumen 1794 formed therein. Although separated walls 1792 are shown in Figure 17 for illustrative purposes, a single uniform structure may be formed such that there are no circular walls 1792.

[0077] Eliminating gaps that may exist in a coil having a rounded cross-section may provide more efficient heat transfer along coil 1780. Heat can be conducted through coil 1780 (and any core, lattice body, and coil disclosed herein), and infills 1796, 1798 can improve such heat conduction, thereby providing higher quality steam, shortening the required passage for the fluid, and thereby reducing the length of coil 1780. The reduction in the length of coil 1780 may provide the space-saving efficiency described above with respect to generator 160. Coil 1780 may be formed of any suitable material such as Inconel by any suitable method such as any additive manufacturing technique described herein. The material of coil 1780 may be uniform or non-uniform to provide efficient heating. The width of wall 1792 and / or infills 1796, 1798 may be uniform or varied to efficiently heat the fluid passing through the lumen of coil 1780.

[0078] Any device described herein may have additional features to provide more efficient heat and / or energy transfer. For example, embodiments described herein may include features formed by any additive manufacturing method described herein. For example, features such as thickened or flattened portions of any coil or core disclosed herein may be formed to provide an improved connection between a thermocouple and / or Litz wire and a coil / core. The thickened or flattened portions may provide a landing pad for the thermocouple, Litz wire, or wire of other structures, and the welding of various structures can be improved by adding a robust area / thickened portion to which the thermocouple, Litz wire, or other structure adheres, thereby avoiding or reducing areas / welds that are susceptible to breakage or leakage.

[0079] The principles of this disclosure are described herein with reference to exemplary embodiments for specific uses, but it should be understood that this disclosure is not limited thereto. Those skilled in the art and with access to the teachings provided herein will recognize that all additional modifications, applications, and substitutions of equivalents fall within the scope of the embodiments described herein. Therefore, the present invention should not be considered limited by the foregoing description.

Claims

1. A steam generator used in medical devices, A heating core comprising two or more coils, wherein the two or more coils comprise a first coil and a second coil, the second coil being concentric with the first coil and radially surrounded by the first coil, the first coil and the second coil being in fluid communication with a fluid supply source, and defining a fluid path through which fluid from the fluid supply source moves, A third coil, positioned around the heating core, is configured to receive an electric current to heat the fluid moving through the fluid path, thereby generating steam. A steam generator equipped with the following features.

2. The steam generator according to claim 1, wherein at least one tube of the first coil and the second coil has a non-circular cross-section.

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