US3913581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic apparatus
Assignee: Spembly Ltd
•
Filing: 1973-06-01
•
Granted: 1975-10-21
•
Expires: 1993-06-01
Abstract
Abstract The invention relates to cryosurgical instruments in which gas cooling by Joule-Thomson expansion is employed in an applicator adapted to contact and thermally cool human tissue, the gas in the cooling mode being carried to an orifice, for expansion therethrough, by a first duct and led away to atmosphere after expansion by a second duct. The invention resides in apparatus and a method of obtaining rapid warming of the applicator by providing valve means for connecting the second duct directly to a source of high pressure refrigerant gas so that gas condenses within the applicator upon any cold surface thereof.
Inventors
- 👤 Carl Ritson
- 👤 Ernest Hilton Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:14
CPC Classifications
F; F25; F25D; F25D3/00; F25D3/10; A; A61; A61B; A61B18/00; A61B18/02; F25B; F25B9/00; F25B9/02; A61B2018/00005; A61B2018/00041
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
217 words
A cryosurgical instrument for use with a remote source of pressurized gas and adapted to operate in a cooling mode and in a rapid warming mode, comprising: a body enclosing a caviyty having a wall of high thermal conductance, said wall being shaped externally for contacting human tissue and providing heat transfer with the tissue and being of sufficient structural integrity to withstand the full source pressure; a first conduit extending through said body and connected to said cavity terminating therein in a restricted orifice through which pressurized gas may expand into said cavity experiencing Joule-Thompson cooling in so doing and thereby cool said wall when said first conduit is connected to said source of gas; a second conduit connected to said cavity; an exhaust passage leading to atmosphere; and valve means for providing a cooling mode gas-flow path from said source of pressurized gas, through said first conduit and said orifice, into said cavity, and then through said exhaust passage, whereby the expansion of as through said orifice cools said wall, and for selectively providing a heating mode gasflow path from said source of pressurized gas, through said second conduit, and directly to said cavity for pressurizing said cavity sufficiently to condense said gas on the cooled wall and liberate latent heat to warm the wall.
Claim 2
Dependent Claim
217 words
A cryosurgical instrument for use with a remote source of pressurized gas and adapted to operate in a cooling mode and in a rapid warming mode, comprising: a body enclosing a caviyty having a wall of high thermal conductance, said wall being shaped externally for contacting human tissue and providing heat transfer with the tissue and being of sufficient structural integrity to withstand the full source pressure; a first conduit extending through said body and connected to said cavity terminating therein in a restricted orifice through which pressurized gas may expand into said cavity experiencing Joule-Thompson cooling in so doing and thereby cool said wall when said first conduit is connected to said source of gas; a second conduit connected to said cavity; an exhaust passage leading to atmosphere; and valve means for providing a cooling mode gas-flow path from said source of pressurized gas, through said first conduit and said orifice, into said cavity, and then through said exhaust passage, whereby the expansion of as through said orifice cools said wall, and for selectively providing a heating mode gasflow path from said source of pressurized gas, through said second conduit, and directly to said cavity for pressurizing said cavity sufficiently to condense said gas on the cooled wall and liberate latent heat to warm the wall.
Claim 3
Dependent Claim
56 words
A cryosurgical instrument according to claim 1 in which said valve means are remote from said body and comprise; a two-position valve which in a second position provides connection for the warming mode and in a first position provides connection for the cooling mode; means which prevent flow through sad first conduit in the warming mode.
Claim 4
Dependent Claim
22 words
A cryosurgical instrument according to claim 2 in which said means for preventing flow in said first conduit is said two-position valve.
Claim 5
Dependent Claim
22 words
A cryosurgical instrument according to claim 2 in which said means for preventing flow in said first conduit is a non-return valve.
Claim 6
Dependent Claim
17 words
A cryosurgical instrument according to claim 2 in which said valve is biased towards said second position.
Claim 7
Dependent Claim
22 words
A cryosurgical instrument according to claim 1 in which said valve means comprise a pressure operated two-position valve situated in said body.
Claim 8
Dependent Claim
48 words
A cryosurgical instrument according to claim 1 in which said valve means comprise a three-position valve which, in a first position, provides connection for the cooling mode, in a second position provides connection for the warming mode and in a third position isolates said source of pressurised gas.
Claim 9
Dependent Claim
35 words
A cryosurgical instrument according to claim 7 in which said three position valve, when in said third position, also connects at least the first conduit of said first and second conduits to said exhaust passage.
Claim 10
Dependent Claim
25 words
A cryosurgical instrument according to claim 8 in which said three-position valve when in said second position connects said first conduit to said exhaust passage.
Claim 11
Dependent Claim
29 words
A cryosurgical instrument according to claim 7 in which said three position valve passes through said second position at least when changing from the first to the third position.
Claim 12
Dependent Claim
35 words
A cryosurgical instrument according to claim 10 in which delay means are provided which temporarily maintain said three-position valve in said second position when it is urged from said first position towards said third position.
Claim 13
Dependent Claim
121 words
A cryosurgical instrument according to claim 11 in which said delay means comprise; a pressure operated detent including a bleed orifice through which any gas pressure in said detent may leak away when said detent is fluidly isolated; in which cryosurgical instrument said three-position valve is adapted to (a) operate said Detent by connecting it to said source only when in said first position; and (b) to be maintained in said second position by said operated detent, when changing from said first to said third position, for a period determined by the rate of bleed of gas from said detent when fluidly isolated; means which fluidly isolate said detent from said source when said three-position valve is in said second position.
Claim 14
Dependent Claim
41 words
A cryosurgical instrument according to claim 12 in which said detent isolation means is a non-return valve connecting said detent to said first conduit and said three-position valve when in its second position connects said first conduit to said exhaust passage.
Claim 15
Dependent Claim
39 words
A cryosurgical instrument according to claim 1 in which said restricted orifice includes a non-return valve such that, in the cooling mode, gas flow is restricted but that gas flow is relatively unrestricted in the reverse sense of flow.
Claim 16
Dependent Claim
84 words
A cryosurgical instrument according to claim 14 in which said first conduit terminates in a portion of reduced diameter and in which said non-return valve comprises a free ball of smaller diameter than that of the first conduit bore but greater than that portion of reduced diameter and which seats on the reduced portion under the action of pressure within said first conduit, and is released upon reversal of pressure; in which said restricted orifice is formed in the wall of said reduced portion.
Claim 17
Independent Claim
121 words
A method of cooling and then warming the highly thermally conductive wall of an expension chamber in a cryosurgical instrument, the external surface of the wall providing the applicator surface of the instrument, the method comprising: introducing a pressurized gaseous refrigerant from a source thereof into said chamber through flow-restricting means while connecting said chamber to a region of pressure lower than the pressure of said source, thereby cooling said wall and said applicator surface by the Joule-Thomson effect; and then pressurizing said chamber from said source of pressurized gaseous refrigerant through a flow path separate from said flow-restricting means so that said refrigerant condenses on said wall and liberates latent heat thereto, thereby warming said wall and said applicator surface.
Claim 18
Independent Claim
121 words
A method of cooling and then warming the highly thermally conductive wall of an expension chamber in a cryosurgical instrument, the external surface of the wall providing the applicator surface of the instrument, the method comprising: introducing a pressurized gaseous refrigerant from a source thereof into said chamber through flow-restricting means while connecting said chamber to a region of pressure lower than the pressure of said source, thereby cooling said wall and said applicator surface by the Joule-Thomson effect; and then pressurizing said chamber from said source of pressurized gaseous refrigerant through a flow path separate from said flow-restricting means so that said refrigerant condenses on said wall and liberates latent heat thereto, thereby warming said wall and said applicator surface.
Claim 19
Dependent Claim
14 words
A method as described in claim 16 wherein the gaseous refrigerant is carbon dioxide.
Claim 20
Dependent Claim
15 words
A method as described in claim 16 wherein the gaseous refrigerant gas is nitrous oxide.
Claim 21
Dependent Claim
21 words
A method as set forth in claim 16, wherein said introducing is effected through a conduit having said flow-restricting means therein.
Claim 22
Dependent Claim
16 words
A method as set forth in claim 19, wherein said conduit is blocked during said warming.
Claim 23
Dependent Claim
19 words
A method as set forth in claim 19, wherein said conduit is connected to said source during said warming.
Claim 24
Dependent Claim
18 words
A method as set forth in claim 19, wherein said conduit is connected to atmosphere during said warming.
Claim 25
Dependent Claim
116 words
A cryosurgical instrument according to claim 1, in which said body is a hollow cylindrical body having said first conduit extending therethrough from one end of the body and into said cavity at the opposite end, said second conduit and said exhaust passage being connected to said body at said one end, said valve means comprising a valve member slidably mounted in said body at said one end of said body and having means for connecting said second conduit and said exhaust passage to said cavity alternately in response to gas pressure in said second conduit, said valve means further comprising a control valve for selectively connecting said second conduit to said source or to atmosphere.
References Cited (Backward Citations)
US3067589A
Cited
US3502081A
Cited
US3393679A
Cited
US3512531A
Cited
US3548829A
Cited
US3613689A
Cited
US3762179A
Cited
US3696813A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |