Source: http://www.google.es/patents/US20030130650
Timestamp: 2017-10-21 16:17:27
Document Index: 72864113

Matched Legal Cases: ['§119', 'Application No. 60', 'art 190', 'art 192', 'art 188', 'art 188']

Patente US20030130650 - Miniature refrigeration system for cryothermal ablation catheter - Google Patentes
A cryocatheter for treating cardiac arrhythmias comprises a miniature refrigeration system powered by electromagnetic radiation. The miniature refrigeration system is disposed at the tip of the catheter and electromagnetic radiation is delivered to the refrigeration system by a waveguide. The miniature...http://www.google.es/patents/US20030130650?utm_source=gb-gplus-sharePatente US20030130650 - Miniature refrigeration system for cryothermal ablation catheter
Número de publicación US20030130650 A1
Número de solicitud US 10/328,380
También publicado como US6949094, US7615048, US20050277914, US20100057066, WO2003053496A2, WO2003053496A3
Número de publicación 10328380, 328380, US 2003/0130650 A1, US 2003/130650 A1, US 20030130650 A1, US 20030130650A1, US 2003130650 A1, US 2003130650A1, US-A1-20030130650, US-A1-2003130650, US2003/0130650A1, US2003/130650A1, US20030130650 A1, US20030130650A1, US2003130650 A1, US2003130650A1
Citas de patentes (39), Citada por (7), Clasificaciones (6), Eventos legales (6)
Miniature refrigeration system for cryothermal ablation catheter
US 20030130650 A1
an elongated body defined between a proximal end and a distal end;
a closed-cycle miniature refrigeration unit including a compressor and at least a first heat exchanger disposed at the distal end; and
a waveguide for conducting electromagnetic energy, the waveguide extending from the proximal end of the elongated body to the distal end and cooperating with the compressor so as to provide electromagnetic radiation to drive the compressor.
2. A cryo-medical apparatus as in claim 1, wherein the elongated body comprises a guidewire lumen.
9. A cryo-medical system comprising:
a cryo-medical apparatus including an elongated body defined between a proximal end and a distal end, a closed-cycle miniature refrigeration unit including a compressor and at least a first heat exchanger disposed at the distal end, and a waveguide for conducting electromagnetic energy, the waveguide extending from the proximal end of the catheter body to the distal end and cooperating with the compressor so as to provide electromagnetic radiation to drive the compressor;
a coupler for coupling the source of electromagnetic radiation to the waveguide.
10. A cryo-medical system as in claim 9, additionally comprising a coolant supply disposed externally of the cryo-medical apparatus, the elongated body of the cryo-medical apparatus defining a plurality of lumens, and at least one of the lumens being coupled to the coolant supply.
11. A closed-cycle miniature refrigeration system comprising:
a compressor having a housing defining at least one chamber, a liquid piston positioned to reciprocate within the chamber, and a source of electromagnetic radiation energizing the liquid piston by exposing a portion of the liquid piston to electromagnetic radiation, the source of electromagnetic radiation driving the liquid piston to reciprocate within the chamber, the liquid piston compressing a working fluid; and
a heat exchanger communicating with the compressor in a manner permitting circulation of coolant fluid between the compressor and the heat exchanger.
12. A miniature refrigeration system as in claim 11, additionally comprising a Joule-Thomson expander disposed between the compressor and the heat exchanger.
13. A miniature refrigeration system as in claim 11, wherein the housing comprises a valve mechanism that selectively permits ingress and egress flow into and out the chamber on one side of the liquid piston.
14. A miniature refrigeration system as in claim 11, wherein refrigerant from the heat exchanger flows into the housing through the valve mechanism such that a portion of the refrigerant in the system functions as the working fluid in the compressor.
15. A miniature refrigeration system as in claim 12 additionally comprising a compressor pump, the compressor pump being operatively coupled with the chamber such that the working fluid drives the compressor pump.
16. A miniature refrigeration system as in claim 15, wherein the compressor pump comprises a flexible diaphragm.
17. A miniature refrigeration system as in claim 11, wherein the housing includes a cooling jacket that surrounds at least a portion of the chamber.
18. A miniature refrigeration system as in claim 17, wherein the cooling jacket is defined by a plurality of microchannels that communicate with a source of coolant.
19. A medical apparatus comprising:
an engine disposed at the distal end of the elongated body, the engine including a housing defining a chamber and a liquid mass positioned within the chamber; and
a waveguide for conducting electromagnetic energy, the waveguide extending from the proximal end of the elongated body to the distal end and cooperating with the engine so as to heat the liquid mass non-uniformly.
20. A medical apparatus as in claim 19, wherein the housing contains a gas spring disposed within the chamber and within a propagation path of the electromagnetic energy.
21. A medical apparatus as in claim 20, wherein the engine includes a spring mechanism disposed so as to resist movement of the liquid mass away from a distal end of the waveguide.
22. A medical apparatus as in claim 21, wherein the spring mechanism comprises a gas spring.
23. A medical apparatus as in claim 21, wherein the spring mechanism comprises a flexible diaphragm.
24. A medical apparatus as in claim 19, wherein the housing includes a valve system that communicates with the chamber on one side of the liquid mass, the valve system configured to permit the ingress and egress of fluid into and out the chamber.
25. A medical apparatus as in claim 19 in combination with a source of electromagnetic radiation, the source of electromagnetic radiation configured to provide pulses of electromagnetic radiation to a portion of the liquid mass so as to drive the liquid mass at a frequency.
a liquid mass positioned to oscillate within the chamber at a frequency; and
27. An engine as in claim 26, wherein the frequency of oscillation is a natural frequency of oscillation of the liquid mass in said housing, said source delivering pulses of electromagnetic energy at a frequency substantially equal to the natural frequency.
28. An engine as in claim 26, wherein the source of electromagnetic radiation is arranged so as to asymmetrically expose the liquid mass to electromagnetic radiation.
29. An engine as in claim 26, wherein the source of electromagnetic radiation is arranged such that said portion of the liquid mass exposed to radiation includes at least a free surface of the liquid mass.
30. An engine as in claim 26, wherein the energy, pulse duration, energy density and wavelength of said radiation are selected to cause explosive boiling of the portion of the liquid mass within a time period that is less than one-fourth of said period of oscillation.
31. An engine as in claim 30, wherein the time period is on the order of 100 nano-seconds.
32. An engine as in claim 26, wherein the chamber has a width no greater than about 4 millimeters.
33. An engine as in claim 26, wherein the source of electromagnetic radiation is arranged to heat the liquid mass non-uniformly.
34. An engine as in claim 26, wherein a vapor space is provided within the chamber between the liquid mass and the source of electromagnetic radiation.
35. An engine as in claim 34, wherein another vapor space is provided within the chamber on the side of the liquid mass generally opposite to that on which the other vapor space occurs.
36. An engine as in claim 26, wherein the source of electromagnetic radiation is a laser.
37. An engine as in claim 26, wherein the housing includes a cooling jacket that surrounds at least a portion of the chamber.
38. An engine as in claim 37, wherein the cooling jacket is defined by a plurality of microchannels that communicate with a source of coolant.
39. An engine comprising:
a liquid mass disposed within the chamber;
a source of electromagnetic radiation energizing the liquid mass by exposing a portion of the liquid mass to electromagnetic radiation; and
a gas spring disposed within the chamber and within a propagation path of the electromagnetic radiation.
40. An engine comprising:
a liquid mass disposed within the chamber; and
a source of electromagnetic radiation heating a portion of the liquid mass;
wherein the chamber includes first and second end sections and an intermediate section, each of the first and second end sections is formed of a material having a low affinity for the liquid of the liquid mass, and the intermediate section is formed of a material having a higher affinity for the liquid of the liquid mass.
41. A method of oscillating a liquid mass within a housing comprising:
(a) converting a portion of the liquid mass to a gas phase to propel the remainder of the liquid mass within the housing;
(b) reconverting at least a substantial portion of the gas phase portion back to a liquid phase; and
(c) sequentially repeating the acts of (a) and (b) to cause the liquid mass to oscillate.
42. A method as in claim 41, wherein converting a portion of the liquid mass to a gas phase comprises:
directing electromagnetic radiation onto a surface of a liquid mass that is positioned within the housing;
superheating a layer of the liquid adjacent the surface to a temperature above a boiling point of the liquid; and
explosively vaporizing the layer of superheated liquid.
43. A method of converting electromagnetic radiation to kinetic energy comprising:
providing a liquid mass within a chamber of a housing;
exposing a portion of the liquid mass to electromagnetic radiation;
vaporizing at least a portion of the liquid mass to propel the liquid mass in a first direction; and
redirecting the liquid mass in a second direction that is generally opposite the first direction.
44. A method of oscillating a liquid mass within a housing comprising:
converting electromagnetic energy into mechanical work and heat; and
stabilizing the oscillations by removing heat such that the oscillations reach steady state.
45. An engine comprising:
a housing having chamber wall that defines a chamber within the housing;
a spring mechanism positioned within the housing to exert pressure on another surface of the liquid piston.
46. The engine as in claim 45, wherein the spring mechanism comprises a flexible diaphragm disposed adjacent said another surface of the liquid piston.
47. The engine as in claim 45, wherein the spring mechanism comprises a second gas spring.
48. The engine as in claim 47, wherein the first and second gas springs are symmetrically disposed relative to the liquid piston.
The present application is based upon and claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60/341,952, filed Dec. 19, 2001, entitled LASER REFRIGERATOR, which is hereby incorporated by reference.
[0022]FIG. 1 is schematic illustration of a cryothermal ablation system including a cryocatheter, which is configured in accordance with a preferred embodiment of the present invention.
[0023]FIG. 2 is an enlarged sectional schematic view of a distal end of the cryocatheter.
[0024]FIG. 2A is a cross-section of the cryocatheter taken along line 2A-2A of FIG. 2.
[0025]FIG. 3 is a block diagram illustrating the components of a closed loop refrigeration system disposed at the distal end of the cryocatheter.
[0026]FIG. 4A is an enlarged perspective view of a heat exchanger of the refrigeration system that is configured in accordance with a preferred mode of the refrigeration system.
[0027]FIG. 4B is an exploded perspective view of etched foils of the heat exchanger of FIG. 4A in an unformed, pre-assembled state.
[0028]FIG. 5A is an enlarged perspective view of another heat exchanger of the refrigeration system that can be used in the place of the heat exchanger illustrated in FIG. 4A. In particular, FIG. 5A illustrates a stacked etched-disk heat exchanger configured in accordance with another preferred mode of the refrigeration system.
[0029]FIG. 5B is a partially exploded, cross-sectional view of the heat exchanger FIG. 5A taken along line 5B-5B. For illustration purposes only, FIG. 5B shows two disks of the stacked as spaced apart from the body of the stack to illustrate the cross-section of an individual disk and to illustrate the structural identicalness between the disks in the stack.
[0030]FIG. 5C is a cross-sectional view of the heat exchanger of FIG. 5A taken along line 5C-5C and illustrates an annular face of a disk in the stack.
[0031]FIG. 6A is a schematic view of the distal end of the cryocatheter and schematically illustrates a compressor engine of the refrigeration system.
[0032]FIG. 6B is a schematic cross-sectional view of the distal end of the cryocatheter taken along line 6B-6B of FIG. 6A and schematically illustrates the construction of the catheter proximal of the compressor engine. Only those lumens associated with the compressor engine have been illustrated.
[0033]FIG. 6C is a schematic cross-sectional view of the distal end of the cryocatheter taken along line 6C-6C of FIG. 6A and illustrates the construction a central part of a housing of the compressor engine.
[0034]FIG. 6D is a schematic cross-sectional view of the distal end of the cryocatheter taken along line 6D-6D of FIG. 6A and illustrates the construction of a valve mechanism of the compressor that is configured in accordance with a preferred mode of the refrigeration system.
[0035]FIG. 7A is a sectional view that is similar to that of FIG. 6D and illustrates the construction of another valve mechanism that can be used with the compressor.
[0036]FIG. 7B is a cross-sectional view of the valve mechanism taken along line 7B-7B of FIG. 7A.
[0037]FIG. 7C is an enlarged cross-sectional view of a jet valve to illustrates a variation of a valve design for the valve mechanism illustrated in FIGS. 7A and 7B.
[0038]FIG. 7D is an enlarged cross-sectional view of a vortex valve to illustrate another variation of a valve design for the valve mechanism illustrated in FIGS. 7A and 7B.
[0039]FIG. 8 is a schematic illustration of the engine that is used with the compressor in the refrigeration system and that is constructed in accordance with a preferred embodiment of the present invention.
[0040]FIGS. 9A through 9D are schematic sectional views of the compressor engine of FIG. 8 shown at four different stages of an operation cycle.
[0041]FIG. 10A is a schematic illustration of a compressor engine configured in accordance with another embodiment of the present invention.
[0042]FIG. 10B is a cross section of the compressor engine of FIG. 10A taken along line 10B-10B.
[0043]FIG. 10C is a plan view of a distal plate of the compression engine of FIG. 10A as viewed in the direction of section 10C-10C, and illustrates a valve mechanism that regulates fluid flow into and out of the compressor engine.
[0069]FIGS. 5A through 5C illustrate a variation of the counter-flow heat exchanger 158. In this embodiment, the heat exchanger 158 comprises a plurality of stacked disks 174. Preferably, at least most of the disks 174 have the same configuration, and end caps (not shown) close the end disks in the stack. Each disk 174 includes a plurality of annular ribs 176 that are concentrically arranged, as best seen in FIG. 5C. A plurality of openings 178 are disposed between each pair of adjacent ribs 176. When the disks 174 are stacked and joined together, as seen in FIG. 5B, the stacked assembly forms four annular flow channels 180 a, 180 b, 180 c, 180 d. In each flow channel 180 a-d, the fluid flows through the disk openings 178 and then into an annular space defined between adjacent disk ribs 176 (which ribs 176 may be of the same disk 174 or of the adjacent disk 174 depending upon the flow direction). The ribs 176 and the openings 178 preferably are formed on and through the disk 174, respectively, by photo-etching, laser-drilling, EDM (electrical discharge machining) and/or similar processes.
The proximal part 190 and the distal part 192 are preferably made of thermally insulating material with an inner surface having a low affinity for the liquid, resulting in close to adiabatic compression and expansion of the vapor in those chambers. One suitable material is polytetrafluoroethylene (PTFE), available commercially as Teflon™ from E. I. du Pont and Nemours and Company. The central part 188, in addition to having a high affinity for the liquid, preferably is made of a thermally conductive material, such as, for example, copper.
[0078]FIGS. 7A and 7B illustrate another form of a one-way or check valve that employ no moving parts. Through well known principles of fluid dynamics, either a jet valve (FIG. 7C) or a vortex valve (FIG. 7D) can also provide only one-way flow from and to the compressor.
The gas-filled proximal space 200 functions as a gas spring. A gas spring is also formed by the combination of the distal space 202 and the condenser 154 and the evaporator 156 that communicate with the distal space 202. The inertia of the liquid piston 186 and the compression of the gas springs 200, 202 constitute the typical components of an oscillator: the system 150 posses a well-defined natural frequency and is therefore capable of operating at resonance if excited at the right frequency. Consequently, in the present application, the liquid piston can be conceptually modeled as a mass disposed between a pair of springs. This system thus will have a natural frequency (fn) which can be approximated by equation 1: f n = 1 2  π  ( P o L liq  ρ )  ( L gas L gas1  L gas2 ) [ 1 ]
Similarly, the liquid piston 186 should have a diameter sufficient to perform its function. In general, the greater the diameter of the liquid piston 186, the more power can be produced by the engine. At some point, however, increasing the diameter of the liquid piston 186 will lead to loss of capillary action, depending upon the surface tension of the liquid and the affinity of the central part 188 therefor, leading to loss of the liquid piston's integrity during operation. The liquid piston 186 preferably behaves generally as a “plug flow” with a defined boundary layer around its periphery. The thickness of the boundary layer will depend upon the liquid's density and viscosity and upon the system's frequency, as understood from the following equation: λ = 2  μ ωρ [ 2 ]
In the illustrated embodiment, where the distal space directly communicates with the heat exchangers of the refrigeration system 112, the liquid of the liquid piston 186 preferably is the same refrigerant used in the refrigeration system. In one preferred mode, the refrigerant liquid comprises R-134a, having the chemical formula C2H2F2, a critical temperature of 101.2° C. and an estimated practicable superheat limit of about 64° C. (based upon 90% of the critical temperature in Kelvin), as compared to its normal boiling point of −26.5° C. under standard conditions. In another preferred mode, the refrigerant liquid comprises R-12, having the chemical formula CCl2F2, a critical temperature of 112° C. and an estimated practicable superheat limit of about 74° C. (based upon 90% of the critical temperature in Kelvin), as compared to its normal boiling point of −30° C. under standard conditions. Additionally, the refrigerant can comprise a mixture of fluids such as R-134a, R-23, R1-4, and cryogenenic fluids such as helium, hydrogen, neon, nitrogen, and argon. The refrigerant mixture allow the refrigerator to reach temperature as low as 70° K. as taught in U.S. Pat. No. 5,579,654, entitled CRYOSTAT REFRIGERATION SYSTEM USING MIXED REFRIGERANTS IN A CLOSED VAPOR COMPRESSOR CYCLE HAVING A FIXED FLOW RESTRICTION, which disclosure is hereby incorporated by reference.
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