When it is desirable to raise the temperature of the tip 31 connection with FIG. 1. Similarly, the probe assembly 78 is
from this very cold temperature, the surgeon merely depresses secured to the left-hand end of the hand piece 1 la in the same
the valve 45 to align the valve passages 61 and 62 with the manner as described above.
conduits 43—49 and 48—51 so that the liquid refrigerant The bypass passages 74 and 76 in the hand piece and the flows through the conduits 43 and 49 and into the bypass 5 body 77 of the probe assembly communicate through a tube passage 13, and into the space 15 at the right end of the tube 101 to a point in the hollow circular tip 98 opposite the junc27 and the space 58 around the needle-like tube 35. Because ture 102 with the outer tube 97 so that flow from the passages of the restricted passage 22 in the exhaust passage 14 and the 74 and 76 enters the interior space 103 of the tip 98 at the pressurization of the liquid, the entire space 58 is quickly filled farthest point from the aforesaid juncture 102. A tank 40a of with liquid so that the temperature of the tip is raised to the ^ liquid gas is connected to the inlet passage 70 through the flextemperature of the liquid gas, which may be cold but always ible conduit 104 having the filter 44a therein, whereas the exmuch warmer than temperature present during evaporation of haust passage 71 is connected by the flexible conduit 106 to the gas. The restricted passage 22 prohibits the gas from being the vacuum pump 50a which may be of any conventional drawn directly into the exhaust passage 14 although the .„ design. ■ , vacuum continues at all times to remove a portion of this In operation of this embodiment, after the tank 40a of liquid which will be at least partially evaporated. The exhaust refrigerant and the vacuum pump 50a are connected to the gas, whether liquid or gas, is then drawn through the conduit hand piece 11a by the conduits 104 and 106, the valve 42a of 48, the valve passage 62, and the conduit 51 having the check the tank 40a is opened so that the pressure therein forces valve 52 therein. 20 uciuid refrigerant into the inlet passage 70 in the hand piece.
If the surgeon again requires a low temperature at the tip The surgeon will have moved the valve 73 to the closed posi31, he merely removes pressure from the foot pedal 46 and al- tion so that the body 81 blocks the restricted passage 72 and lows the spring 47 to return the valve 45 to the position the refrigerant will flow no further than the valve. When it is wherein the valve passage 57 again connects the conduits 43 desired to cool the circular tip 98 of the probe assembly 78, and 49 at which time the operation described above is recom- 2<i the valve 73 is moved to the open position wherein the menced. The vacuum is sufficient to evacuate quickly the refrigerant flows through the valve passage 88, the restricted space 58 once the supply through the passage 13 is ter- passage 72, and into the needle-like tube 100 from where it is minated. When the surgeon is finished with the instrument, sprayed into the space 103 in the interior of the annular tip 98 the spring 47 returns the valve to the Off position wherein the to reduce the temperature thereof. The evaporation is very conduits 48, 49, and 51 are blocked and further flow of 30 fast and efficient due to the vacuum being applied to the exrefrigerant is not permitted. However, the vacuum continues haust passage 71 in the space by the vacuum pump 50, as to withdraw all of the refrigerant of the instrument through the described above. The gases quickly evaporate and are exhaust passage 14. withdrawn through the passage 71.
Another embodiment of the invention is shown in FIG. 2 When it is desirable to quickly raise the temperature of the
which also includes a pencil-like hand piece 11a which also 35 tip 98, the surgeon moves the knob 95 to the bypass position
can be easily held in the hand of a surgeon. This hand piece in- wherein the liquid refrigerant flows through the valve passage
eludes an elongated body of plastic material having parallel 88 and into the bypass passages 74 and 76, through the tube
inlet and exhaust passages 70 and 71 therein. In the restricted 101, and into the space 103 in the interior of the annular tip
portion 72 of the passage 70 a small valve 73 is provided for 98 and the outer tube 97. Since the liquid floods the tip, no
diverting the flow of liquid into a bypass passage 74 formed in 4() evaporation occurs, and the tip 98 is raised to the temperature
the hand piece 11a, and leading to a complementary passage of the liquid which is much warmer than that created by the
76 in the body 77 of the probe assembly 78. evaporation of the liquid. The vacuum continues to withdraw
As shown in FIGS. 3 and 4, the valve 73 includes a cylindri- the liquid and any gas which may be created into the vent
cal body 81 mounted in a complementary bore 82 in the hand passage 71 through the restricted passage 22 which limits the
piece 11a and held therein by the annular retainer 83 which 45 rate Qf withdrawal so that the flooding can take place. When
surrounds the upstanding stem 84 on the body 81 and engages the valve 73 is moved to the open position again, the tip is
the complementary threads 85 on the outer end of the bore. A again cooled as the vacuum draws the flooded refrigerant
suitable washer 86 is provided between the shoulder 87 on the therefrom. Moreover, if the valve 73 is turned to the Off posi
body of the retainer for frictionless rotation of the latter. The tion the vacuum will continue to exhaust all refrigerant from
O-ring seals 89 are interposed between the body 81 and the the bypass system.
hand piece 11a to block the escape of gas or liquids therefrom. Another embodiment of the invention is shown in FIGS. 7
A passageway 88 is provided centrally through the body and 8, including the hand piece 1 lb having parallel inlet and
adapted to communicate with the opposite ends 90 and 91 of vent passages 120 and 121 therein. The probe 123 has its body
the restricted passage 72. The right-hand end 93 of this valve ^ 124 threadedly secured in the recessed end 125 of the hand
passage 88 is is enlarged so that it remains in communication piece lib and the O-ring seal 126 insures that the refrigerant
with the right-hand end 90 of the passage 72 as the valve 73 is will not escape through the threaded connection. The tip 127
rotated to a position wherein the left-hand end is in communi- includes an elongated U-shaped outer tube 128 which com
cation with the bypass passage 74, as shown in FIG. 3. A suita- municates with the passage 130 and 131 in the body of the
ble knob 95 is provided on the stem 84 for turning the valve 73 probe which in turn are aligned with the inlet and vent
between an Off positon wherein the passage 88 is not aligned passages 120 and 121. The needle-like inner tube 132 is
with either of the passage 72 or 74, the straight through posi- mounted in the passage 130 for conducting the liquid
tion as shown in FIG. 2 wherein the valve passage 88 connects refrigerant to the end portion 134 of the tip. As shown in FIG.
the passages 70 and 72, and the bypass position as shown in 8, the end portion of the tip is filled with a porous plastic
FIG. 3 wherein it connects the passages 70 and 74. A pointer 65 material 135 having maximum amount of surface area, such as
96 is provided on the knob 95 for indicating the position of the Zitex, which insures that the liquid will be spread over the sur
valve 73. faces thereof and quickly evaporated.
The probe assembly 78 in this embodiment includes the In operation, the tank 40b of refrigerant is connected to the
elongated outer tube 97 having a circular shaped tip 98 on the inlet passage through the flexible conduit 137 and the filter end thereof, as shown in FIG. 5. The outer tube 97 and the tip 70 44b, and when the valve 41fc on the tank is opened, the
98 are hollow and the needle-like inner tube 100 extends refrigerant flows through the inlet passage 120, and into the
through the outer tube and approximately one-half way inner tube 132 and then is sprayed from the end thereof into
around the circular tip 98. This inner tube is held in the outer the end portion 134 of the tip. Much of the evaporation occurs
tube 97 by the brackets 99, and is adapted to engage the as the refrigerant is sprayed from the tube 132, but any
restricted passage in the same manner as described above in 75 remaining liquid quickly spreads on the surfaces of the porous