Patent Description:
Entities used in a cryogenic system, such as a Dewar or a medical probe, are typically well-insulated to reduce evaporation of cryogen, and are also typically well-sealed to prevent ingress of elements such as moisture. In order to connect the entities, any connector should provide the same properties of good insulation and sealing, while permitting connection and disconnection of the entities.

<CIT> describes a coupling device for a line conduit conveying cryogenic liquids. The device is stated to be of the easy make-and-break type and to comprise two connectable coupling bodies. <CIT> describes a coupling device for cryogenic fluids which allows passage of liquid and vapor simultaneously through one coaxially arranged assembly. The device is stated to have low heat transfer insulation integral with the coupling and also the ability to connect and disconnect without use of tools. <CIT> describes an interface for a magnet Dewar which includes a low leakage disconnect fitting that retains the vacuum integrity of both the Dewar and a connected transfer line.

<CIT> describes a coupling assembly for dispensing cryogenic fluids. The assembly has an upstream terminus coupled to a source of cryogenic fluid and a downstream terminus connected to a container for receiving the cryogenic fluid. A poppet valve assembly is disposed at the upstream dispensing terminus.

<CIT> describes a cryogenic fluid coupling that has a male half and a female half. Each half has a poppet valve arranged to move toward and way from a seat. The male half has an outer sleeve which is adapted to guide initial joinder of the female half distal end.

<CIT> describes a cryo-probe wherein refrigerant is furnished from a high pressure, room temperature supply. Refrigerant flows through a pre-cooling heat exchanger in the probe and through a restrictor wherein the pressure drops. A concentric gas coupling may be used at a warm end of the probe, whereby a nut that threadably engages external threads on a body, rigidly connects the body to a core and a nipple.

<CIT> describes controlling the flow rate of a liquid cryogen by controlling variably the pressure propellant gas acting directly or indirectly on the liquid cryogen.

<CIT> describes a cryosurgical instrument having a Dewar and a cap which is threaded onto the Dewar when in use, with a main valve portion secured to the cap by threads. The handedness of the threads on the main valve portion are opposite to the handedness of the cap threads. <CIT> describes a liquid cryogen withdrawal device that includes a plug for insertion into the neck of a cryogen-containing Dewar in a gas-tight relationship. <CIT> describes a coupling for connecting vacuum-insulated line ends via a coupling socket and a coupling plug. The socket and the plug are provided for conveying a cryogenic medium and have closing elements.

<CIT> describes a cryogenic coupler that includes a socket and a plug that can be detachably inserted into the socket. The socket and the plug have passages for passing a cryogenic medium therethrough, and are provided with valves for blocking the respective passages when the plug is disconnected from the socket.

<CIT> describes a coupling device that can connect two cryogenic fluid conduits in fluid communication without creating a temperature change. The coupling device is stated to have a fluid flow path with a substantially constant cross-sectional area. The coupling device is stated to be designed to be easy to connect and disconnect and to provide a secure connection, in particular at a low temperature.

<CIT> describes a cryogenic coupling device that includes a valved receptacle and a valved nozzle. Rollers in an outer collar of the receptacle are received in helical channels along a collar of the nozzle. A notch or detent in each of the channels provides a vent position to vent fluid before the nozzle is fully disconnected from the receptacle.

<CIT> describes a quick connector coupling for forming a joint in a fluid line system. The quick connector coupling has a female connector body, a male member and a latch coupled to the connector body.

<CIT> describes a disposable probe assembly that includes a breakaway collar. The collar, when twisted away, activates a finger lock element.

<CIT> describes a quick disconnect assembly that includes a reusable assembly including a distal end having a male lip. There is a disposable assembly having quick disconnect capabilities when utilized with the reusable assembly.

<CIT> describes a cylindrical quick disconnect female cryogenic coupler, interconnected with a cryogenic fluid transfer apparatus. The coupler includes a coupler body with a first cavity housing a laterally severed tubular bushing, and an adaptor having one end attached to the coupler body and another end to the apparatus. <CIT> describes a liquid cryogen fluid system for providing cryogenic liquid to a cryoprobe. Flow of cryogen from a cryogen source to the cryoprobe is induced by pressurizing the cryogen source with air delivered by a pressurization pump. <CIT> describes an apparatus that enables quick disconnect termination or connection for cryogenic transfer lines. The apparatus is a connector that will allow two lines to be connected and coupled to simultaneously allow fluid flow to occur and electrical communication to ensue. The connection and termination are stated to occur successfully under a pressurized environment.

<CIT> describes a cryogenic medical device for delivery of subcooled liquid cryogen to various configurations of cryoprobes. The device is a closed or semi-closed system in which the liquid cryogen is contained in both the supply and return stages.

<CIT> describes a first pliable element defining a cooling chamber and a second pliable element which partially encloses the first pliable element, thereby defining a junction between the first and second pliable element. A check valve is included which is in fluid communication with the junction.

<CIT> describes a cryogenic system that includes a reservoir containing a liquid cryogen and a sub-cooling coil immersed in the liquid cryogen. The cryogen is supplied to the sub-cooling coil and is cooled under pressure to produce a pressurized mixed phase cryogen within the sub-cooling coil. This pressurized mixed phase cryogen is provided via a supply line to a cryo-device for use by the device.

<CIT> describes a device, for freezing body tissue, having a main driving system capable of generating nitrogen under physical conditions near a critical point of a liquid-vapor system for the nitrogen.

<CIT> describes a liquid nitrogen delivery and flow regulation system that may be used to regulate the temperature of a cold cavity. Liquid nitrogen is delivered to a liquid nitrogen boiler from a storage Dewar. The Dewar is filled through a coupling connector attached to a feed-line that enters into a manifold. Liquid nitrogen inflow to the Dewar is regulated by an electrically controlled valve that receives signals from a control board on a control line. During the Dewar filling cycle, internal back-pressure in the Dewar is released by an electrically controlled gas release valve that is operated by a signal control line. <CIT> describes a vapor plug, which partially seals an opening of a Dewar. The vapor plug includes a vapor plug cover which is configured to cover an opening of the Dewar. The vapor plug includes a neck that is formed from multiple disks and multiple sheets. The vapor plug includes a fastener that connects the multiple disks, the multiple sheets and the vapor plug cover. <CIT> describes apparatus for delivery of cryosurgery fluid in a surgical or other medical environment. The apparatus comprises a multiple-layered expanded polytetrafluoroethylene conduit that has a low profile, has low thermal conductivity, and is stated to provide exceptional flexibility.

<CIT> describes a supply line that supplies cryogenic liquid to a plurality of cryogenic freezers. A fill line having a diameter greater than the supply line allows a storage tank to be filled at a greater speed relative to filling through the supply line and allows the storage tank to be filled while supplying cryogenic liquid to the cryogenic freezers.

<CIT> describes a connector connecting a gas storage tank and a Dewar. The connector has a threaded sleeve piece used for connecting with a fluid outlet of the gas storage tank. There is a corresponding connector body used for filling of the Dewar.

<CIT> describes an infra-red radiation detector having a Dewar type vessel. The detector has a coupler which is coupled to the wall of the vessel. The coupler includes a fibre which can transmit infra red radiation and which terminates close to a detector provided in the Dewar type vessel.

<CIT> discloses a connection unit for connecting fluid lines, wherein the connection unit comprises a first connection body and a second connection body, wherein the connection unit comprises a machine-readable code which is not detectable when the first connection body and the second connection body are in an unconnected state and which is detectable when the first connection body and the second connection body are in a connected state.

<CIT> discloses a male coupling for attaching to a female coupling in which rotation of the male coupling with respect to the female coupling is limited. In one embodiment, the male coupling has one or more tabs extending from a flange, the tabs limiting rotation when the male coupling is mated to a female coupling assembly for fluid conductors.

According to an aspect of the present invention, there is provided a cryogenic apparatus as set out in the first of the appending independent claims. There is also provided, in accordance with another aspect of the present invention, a method as set out in the second of the appending independent claims. Features of various embodiments are set out in the appending dependent claims.

There is disclosed herein a cryogenic apparatus, comprising: a cryogenic probe; a connector having a connector base plate configured for connection to a conduit carrying a cryogen and a slot extending across the base plate; a plug, which is configured for insertion into an opening in the base plate; a latch plate configured to slide within the slot between a first position, in which the plug is configured for being inserted through an aperture in the latch plate into the opening, and a second position, in which the cryogenic probe is configured for being inserted through the aperture and being brought into fluid communication with the opening; and a sensor, which is coupled to control a flow of the cryogen through the conduit by detecting whether the latch plate is in the first position or the second position.

In examples, the plug has a groove, and the aperture grips the groove, when the plug is inserted through the aperture, so as to lock the plug to the latch plate. In examples, the cryogenic probe has a groove, and the aperture grips the groove, when the probe is inserted through the aperture, so as to lock the probe to the latch plate. In examples, there is a control rod which penetrates a further aperture in the latch plate and which is configured to operate the sensor. In examples, there is a control rod which penetrates a further aperture in the latch plate and which, when the latch plate is in the first position, is in a first control rod position that deactivates the sensor so as to prevent flow of the cryogen, and when the latch plate is in the second position, is in a second control rod position that activates the sensor so as to permit flow of the cryogen. In examples, there is a control rod which penetrates a further aperture in the latch plate and which, when the latch plate is in the first position, is in a first control rod position that prevents the latch plate from moving from the first position, and when the latch plate is in the second position, is in a second control rod position that prevents the latch plate from moving from the second position. Preferably, the control rod, when translated from the first control rod position permits the latch plate moving from the first position, and, when translated from the second control rod position permits the latch plate moving from the second position.

There is also disclosed herein a method, comprising: providing a cryogenic apparatus comprising: a cryogenic probe; a connector having a connector base plate configured for connection to a conduit carrying a cryogen and a slot extending across the base plate; a plug configured for insertion into an opening in the base plate; a latch plate; and a sensor; sliding the latch plate within the slot between a first position, in which the plug is configured for being inserted through an aperture in the latch plate into the opening, and a second position, in which the cryogenic probe is configured for being inserted through the aperture and being brought into fluid communication with the opening; and coupling the sensor to control a flow of the cryogen through the conduit by detecting whether the latch plate is in the first position or the second position.

The present disclosure will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings, in which:.

In a medical cryogenic procedure, it is important, from a safety point of view, to maintain the cryogen isolated and sealed from the surgeon performing the procedure, and from the patient undergoing the procedure, so that neither have any direct exposure to the cryogen. The procedure typically involves connecting and disconnecting a probe, which in some embodiments may be a sterile disposable probe, used for the procedure from a Dewar storing the cryogen, and at both times there may be leakage of the cryogen. In addition, when the probe is disconnected from the Dewar, it is important to seal the connection to the Dewar to reduce evaporation of the cryogen, to prevent ice forming on the connection, and to prevent expulsion of the cryogen from the Dewar. While speed and simplicity of operation is important for connecting and disconnecting the probe, as well as for sealing the connection, it is equally important, if not more so, that these actions cannot occur inadvertently.

Embodiments of the invention address these considerations by providing a connector to a Dewar storage unit that has a pump for the stored cryogen. The connector, together with a latch incorporated in the connector, has three states: a sealed state, which has a sealing plug in the connector, an active state, when the probe is in the connector, and an intermediate state when neither the sealing plug nor the probe are in the connector. Change from the intermediate state to either the sealed state or the active state, by respective insertion of the sealing plug or the probe into the connector, is fast and simple, and may be accomplished with only one hand. Once inserted, the latch locks the probe or the plug in place, so that inadvertent removal is not possible.

In addition, for safety, there is an activation mechanism attached to the latch so that removal of the plug or the probe requires initially operating the mechanism with two fingers of one hand, so as to free the plug or probe. Once freed, the other hand may extract the plug or probe. Also for safety, the mechanism is configured to detect the presence of the plug and the probe when they are inserted into the connector, by activating respective sensors indicating the presence of the plug or of the probe. Detection of the presence of the plug renders the Dewar pump inoperative, but when the presence of the probe is detected, the pump may be operated.

In the following description, like elements in the drawings are identified by like numerals. In addition, all directional references (e.g., upper, lower, upward, downward, left, right, top, bottom, above, below, vertical, and horizontal) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of embodiments of the invention.

Reference is now made to <FIG>, which is a schematic illustration of an apparatus <NUM> being used for a cryogenic medical procedure, according to an embodiment of the present invention. By way of example the procedure assumed in the following description is on a breast tumor, but it will be understood that apparatus <NUM> may be used for other procedures, such as on a prostate or kidney tumor, and all such procedures are considered to be comprised within the scope of the present invention.

The procedure is performed by a physician <NUM> on a patient <NUM>, and the physician has inserted a distal end <NUM> of a probe <NUM> into the patient. Typically, probe <NUM> is non-disposable, as is assumed in the following description. In some embodiments probe <NUM> comprises a sterile disposable probe, and those having ordinary skill in the art will be able to adapt the following description, mutatis mutandis, for this type of probe. The physician may observe an image of the procedure on a screen <NUM>.

A proximal termination <NUM> of the probe is inserted into an opening <NUM> in a connector <NUM> of a cryogen storage unit <NUM>. Storage unit <NUM> is operated by a processor <NUM>, and, inter alia, comprises a cryogen pump <NUM> and a cryogen delivery section <NUM>, both of which are under control of the processor. In one embodiment delivery section <NUM> comprises a cylindrical lumen <NUM>, also herein termed a conduit <NUM>, having a plurality of different diameters. Section <NUM> and conduit <NUM> are illustrated in <FIG>.

A distal end of termination <NUM> is configured to mate with conduit <NUM>, the distal end acting as a male section and the lumen as a female section. Once mated, the combination forms a cylindrical supply lumen <NUM> and a tubular return lumen 67R, and which may be used for delivery and return of cryogen. (Lumens <NUM> and 67R are illustrated in <FIG>. ) Thus, cryogen <NUM> contained in the storage unit may be delivered via supply lumen <NUM> and the proximal end, through the probe, to the distal end. Cryogen returns from the distal end via the probe and the proximal end and return lumen 66R to the storage unit.

During the procedure it is important that proximal termination <NUM> is not removed from connector <NUM>. Such removal, typically inadvertent, may cause cryogen to escape from lumens <NUM> and 66R and/or proximal termination <NUM>. Such an escape is a safety hazard. To prevent inadvertent removal, once the proximal termination has been inserted into the connector and mated with the lumens, a latch plate <NUM> in the connector automatically locks the proximal termination to the connector. As a further safety aspect, unlocking of the proximal termination from the connector, permitting removal of the proximal termination, may only be implemented positively, by simultaneous actuation of a button <NUM> and a latch plate retainer <NUM>, the retainer being fixedly attached to the latch plate. The construction and operation of the latch plate in connector <NUM> is described in more detail with respect to <FIG>, <FIG>, below.

<FIG> and <FIG> are schematic drawings of connector <NUM>, according to an embodiment of the present invention. The figures illustrate the connector in a number of different views, without proximal termination <NUM> being inserted into the connector. A callout "A" also illustrates two opposing faces 76A, 76B of latch plate <NUM>, and a figure "B"illustrates a front view of the latch.

For clarity in the description herein, connector <NUM> is assumed to be drawn on a set of xyz orthogonal axes. In a disclosed embodiment, the z axis is assumed to be collinear with the axis of symmetry of lumen <NUM> and to have a positive direction that extends proximally and horizontally from section <NUM>. Latch plate <NUM> is formed, in a disclosed embodiment, as a generally rectangular plate that is normal to the z axis, and that has edges that are assumed to be vertical and horizontal. The positive y axis is assumed to be parallel to a vertical edge of plate <NUM>, directed up; the positive x axis is assumed to be parallel to a horizontal edge of plate, directed right when viewed distally along the z axis. An origin of the axes is assumed to reside in the plate. It will be appreciated that the orientations described herein are for clarity and by way of example, and that embodiments of the present invention may function in substantially any orientation.

Latch plate <NUM> is held between a connector base plate <NUM>, lying in an xy plane, and a connector cover <NUM>. In base plate <NUM> are two shoulders, 96A 96B, both parallel to the y-axis and protruding from the plate in a positive z-direction, separated by the width of the latch plate, and the latch plate is positioned between the shoulders. The shoulders constrain the plate to move in a slot <NUM>, between the shoulders, parallel to the y-axis. (Because it is attached to plate <NUM>, plate retainer <NUM> also moves parallel to the y-axis.

Latch plate <NUM> has two apertures formed within the plate: a generally slot-like aperture <NUM>, parallel to the y-axis, and a generally oval aperture <NUM> which is penetrated by the z-axis. More details of the structure and the function of the apertures are given below.

A cylindrical rod <NUM> (shown also in cross-section in the figure), which is formed as a plurality of solid cylinders 108A, 108B, 108C, of different diameters, penetrates slot-like aperture <NUM>. Cylinder 108A has two circular grooves 108A1, 108A2 formed in the cylinder. There is a shoulder <NUM> between cylinder 108A and cylinder 108B, and a shoulder <NUM> between cylinders 108B and 108C.

Aperture <NUM> has two different slots <NUM>, <NUM>, each slot having a depth that is half the thickness of plate <NUM>. Slot <NUM> has two different widths, an upper part <NUM> and a lower part <NUM> having a width corresponding to the diameter of cylinder 108C, and a central part <NUM> having a width corresponding to the diameter of cylinder 108B. Slot <NUM> is in four different sections, an upper section <NUM> and a lower section <NUM>, both terminating in a semicircle and having a width corresponding to the diameter of cylinder 108C, an upper middle section <NUM> having the diameter of cylinder 108B, and a partially circular lower middle section <NUM>, having a diameter equal to the diameter of cylinder 108A. There is an internal surface <NUM> in plate <NUM>, formed by the different widths of the two slots.

Button <NUM> connects to a proximal end of cylindrical rod <NUM>. A distal end of the rod is held within a rod holder <NUM>, which is fixed to base plate <NUM>. The rod holder has a blind hole <NUM> having a diameter corresponding to the diameter of cylinder 108A of rod <NUM>, and there is a spring <NUM> within the blind hole contacting the rod distal end, the spring pushing the rod in a positive z-direction. It will be appreciated that rod <NUM> is able to slide in hole <NUM> in a z-direction.

Rod holder <NUM> acts as a support for two printed circuit (PC) boards PC1, PC2. Board PC1 has two pairs of radiation transmitters TX1A, TX1B, and TX2A, TX2B, herein by way of example assumed to comprise infra-red emitters. Board PC2 has two pairs of receivers RX1A, RX1B, and RX2A, RX2B configured to receive the radiation transmitted by the transmitters. Herein by way of example the receivers are assumed to comprise phototransistors. There are four channels C1A, C1B, C2A, C2B, in holder <NUM>, and transmitters TX1A, TX1B, TX2A, TX2B are aligned respectively with channels C1A, C1B, C2A, C2B and with receivers RX1A, RX1B, and RX2A, RX2B. Thus, absent any obstruction in the channels, radiation from the transmitters is received by, and activates the receivers.

As is described below, cylinder 108A does obstruct the channels, except when grooves 108A1 or 108A2 align with a channel.

As is explained further below, receivers RX1A, RX1B, RX2A, RX2B, act as sensors, and are also termed herein sensors RX1A, RX1B, RX2A, RX2B. Sensors RX1A, RX1B, RX2A, RX2B detect, inter alia, the position of latch plate <NUM> in slot <NUM>.

As stated above, latch plate <NUM> is constrained to move in a y-direction, in slot <NUM>, by shoulders 96A, 96B. The plate is pushed in a positive y-direction by springs <NUM>, which are held between plate retainer <NUM> and cover <NUM>. In the state illustrated in <FIG> and <FIG>, i.e., where proximal termination <NUM> is not in the connector, the plate is prevented from moving in a y-direction by a semicircular section <NUM> of aperture <NUM> contacting a circular split lip <NUM> protruding in a z-direction from a latch backing disc <NUM>. Disc <NUM> and split lip <NUM> are maintained in contact with plate <NUM> by springs <NUM>, which push the disc in a positive z direction, and which permit the disc to move along the z axis.

In the situation illustrated in <FIG> and <FIG>, latch plate <NUM> is in its lowest possible y-position. In the illustrated situation an upper semicircular section <NUM> of section <NUM> mates with cylinder 108C of rod <NUM>. In addition, by virtue of the force exerted in the positive z direction by spring <NUM> on rod <NUM>, shoulder <NUM> between cylinder 108B and cylinder 108C is pushed against face 76B of plate <NUM>. Consequently, rod <NUM> is fixed in a position where it is unable to move parallel to the z-axis. In this position, neither groove 108A1 nor groove 108A2 align with any of channels C1A, C1B, C2A, C2B. Rather, the channels are obstructed by cylinder 108A, so that none of sensors RX1A, RX1B, RX2A, RX2B, activate.

As is described below, in embodiments of the invention, plate <NUM> and rod <NUM> are in other positions, but in the situation illustrated in <FIG> and <FIG>, where there is nothing inserted in aperture <NUM>, latch plate <NUM> is in its lowest possible y-position, and rod <NUM> is in its most distal position measured parallel to the z axis.

<FIG> is a schematic drawing of connector <NUM> when proximal termination <NUM> of probe <NUM> is inserted into the connector, according to an embodiment of the present invention. The figure illustrates the connector and the termination in a perspective view, substantially as shown in <FIG> and in a cross-section view. The figure also illustrates the connector in a perspective view.

Termination <NUM> fits within conduit <NUM>, forming cylindrical supply lumen <NUM> and connecting to tubular return lumen 67R. Termination <NUM> has an axis of symmetry that, when it is in the conduit <NUM>, is collinear with the z-axis. On insertion of termination <NUM> into opening <NUM>, the termination pushes lip <NUM> and its latch backing disc <NUM> in a negative z-direction against springs <NUM>, so that the lip disengages from semicircular opening <NUM>. The disengagement permits latch plate <NUM> to move in a y-direction, and springs <NUM> push the plate in a positive y-direction.

Latch plate <NUM> moves in a positive y-direction until opening <NUM> engages with a circular groove <NUM> in termination <NUM>. The engagement grips the termination, and locks it in place so that the termination may not be removed from opening <NUM>, except as described below. Groove <NUM> has a radius R<NUM>, and it will be appreciated that it is the value of R<NUM> that determines the location of latch plate <NUM> when termination <NUM> is in place, and so determines the distance moved by the latch plate when the termination is inserted into opening <NUM>.

The vertical movement of latch plate <NUM> causes shoulder <NUM> of rod <NUM> to slide in slot-like aperture <NUM> against face 76B of the latch plate. While shoulder <NUM> slides against face 76B, the sliding continues until the slot that rod <NUM> is in enlarges, at section <NUM> (<FIG>); at this point spring <NUM> pushes rod <NUM> in a positive z-direction until shoulder <NUM> contacts internal surface <NUM>.

The positive z-direction movement of rod <NUM> causes groove 108A2 to align with channels C2A and C2B, so that the channels are not obstructed. (Channels C1A and C1B are obstructed by cylinder 108A. ) Consequently transmitters TX2A and TX2B activate respective sensors RX2A and RX2B. The sensor activation acts as a positive indication that termination <NUM> has been inserted into opening <NUM>. The positive indication from the sensors may be used by delivery section <NUM> to recognize that it is safe to permit flow of cryogen from storage unit <NUM>, and thus to activate the delivery section. As is described further below, deactivation of the sensors prevents cryogen flow.

To remove termination <NUM> from opening <NUM>, the termination must be disengaged from latch plate <NUM>. The disengagement requires the latch plate to move down, so that circular groove <NUM> is no longer gripped by the latch plate, but in the state illustrated in <FIG> this is not possible, since cylinder 108B contacts an upper part of upper middle section <NUM>.

Embodiments of the invention provide a two step method for removal of termination <NUM>. As a first step button <NUM> is pushed in, typically by one finger or a thumb of physician <NUM>, so that cylinder 108B no longer contacts an upper part of upper middle section <NUM>. Springs <NUM> still maintain the latch plate gripping groove <NUM>, but the removal of contact between cylinder 108B and section <NUM>, permits a second step.

In the second step, the physician uses a second of his/her digits to press down on plate retainer <NUM>, so that latch plate <NUM> moves in a negative y-direction, and disengages from groove <NUM> of the termination. The physician may then remove the termination.

It will be understood that the first step, of pushing button <NUM> in, deactivates sensors RX2A and RX2B, by blocking the channels to the sensors. The sensor deactivation may be used to deactivate cryogen delivery section <NUM> of cryogen unit <NUM> and operation by processor <NUM> of pump <NUM>, so preventing cryogen flow from the section and from the unit. It will also be understood that inadvertent pushing of button <NUM> and pressing retainer <NUM> deactivates sensors RX2A and RX2B, and thus halts cryogen flow by deactivating delivery section <NUM> and pump <NUM>.

<FIG> is a schematic drawing of connector <NUM> when a sealing plug <NUM> is inserted into the connector, according to an embodiment of the present invention. The figure illustrates the connector and the plug in a perspective view, substantially as shown in <FIG> and in a cross-section view. The figure also illustrates the connector in a perspective view.

When probe <NUM> is not in use, cryogen unit <NUM> may be sealed by plug <NUM>, in order to prevent air and/or moisture entering the unit, as well as to reduce the evaporation of any cryogen in the unit, and to prevent any uncontrolled release of cryogen.

Plug <NUM> fits within lumen <NUM>, being held in the lumen by an O-ring <NUM>, and the plug has an axis of symmetry that, when it is in the lumen, is collinear with the z-axis. On insertion of plug <NUM> into opening <NUM>, the plug pushes lip <NUM> and its latch backing disc <NUM> in a negative z-direction against springs <NUM>, so that the lip disengages from semicircular opening <NUM>. The disengagement permits latch plate <NUM> to move in a y-direction, and springs <NUM> push the plate in a positive y-direction.

Latch plate <NUM> moves in a positive y-direction until opening <NUM> engages with a circular groove <NUM> in plug <NUM>. The engagement grips the plug, and locks it in place so that the plug may not be removed from opening <NUM>, except as described below. Groove <NUM> has a radius R<NUM>, and it will be appreciated that it is the value of R<NUM> that determines the location of latch plate <NUM> when plug <NUM> is in place, and so determines the distance moved by the latch plate when the plug is inserted into opening <NUM>. In embodiments of the invention, R<NUM> and R<NUM> are configured to be different, and in the disclosed embodiment, R<NUM> < R<NUM>.

For the case when R<NUM> < R<NUM>, shoulder <NUM> initially slides as described above for termination <NUM> (<FIG>). Because R<NUM> < R<NUM>, the possible vertical motion of the latch plate is larger than is the case with the termination. Consequently latch plate <NUM> continues moving vertically upwards until rod <NUM> is able to enter central part <NUM> of slot <NUM> (<FIG>). When it enters the central section, spring <NUM> pushes the rod in a positive z-direction until shoulder <NUM> contacts face 76B of the latch plate. In this case cylinder 108B contacts an upper part of central section <NUM>, and this contact prevents the latch plate from moving down.

The positive z-direction movement of rod <NUM> causes groove 108A1 to align with channels C1A and C1B, so that the channels are not obstructed. (Channels C2A and C2B are now obstructed by cylinder 108A. ) Consequently transmitters TX1A and TX1B activate respective sensors RX1A and RX1B. The sensor activation acts as a positive indication that plug <NUM> has been inserted into opening <NUM>.

Typically, when apparatus <NUM> is powered on, processor <NUM> checks, using sensors RX1A and RX1B that plug <NUM> is in place, so that, after removal of the plug, termination <NUM> of probe <NUM> may be inserted into the connector. In addition, on shutting down, processor <NUM> may check, using the sensors, that plug <NUM> is in place, so as to enable an orderly shutdown.

As for termination <NUM>, embodiments of the invention provide a two step method for removal of plug <NUM>. As a first step button <NUM> is pushed in, as for termination <NUM>, typically by physician <NUM> using one of his/her digits. In the second step, which is now permitted since the first step enables the latch plate to be moved vertically, the physician uses a second digit to press down on plate retainer <NUM>, so that latch plate <NUM> moves in a negative y-direction, and disengages from groove <NUM> of the plug. The physician may then remove the plug.

It will be understood that the first step, of pushing button <NUM> in, deactivates sensors RX1A and RX1B, by blocking the channels to the receivers.

Claim 1:
A cryogenic apparatus, comprising:
a cryogenic probe (<NUM>);
a connector (<NUM>) comprising:
a connector base plate (<NUM>) configured for connection to a conduit (<NUM>) carrying a cryogen, and
a slot (<NUM>) extending across the base plate;
a plug (<NUM>), which is configured for insertion into an opening (<NUM>) in the base plate;
a latch plate (<NUM>) configured to slide within the slot between a first position, in which the plug is configured for being inserted through an aperture (<NUM>) in the latch plate into the opening, and a second position, in which the cryogenic probe is configured for being inserted through the aperture and being brought into fluid communication with the opening; and
a sensor (RX1A, RX1B, RX2A, RX2B), which is coupled to control a flow of the cryogen through the conduit by detecting whether the latch plate is in the first position or the second position.