US3053254A - Driver and heater for disc oxygenator - Google Patents

Description

Se t. 11, 1962 J. E. GALAJDA, JR

DRIVER AND HEATER FOR nxsc OXYGENATOR 4 Sheets-Sheet 1 Filed June 18, 1959 John E Gala d0, .1:

- 1N VEN TOR. BY @Maviih.

p 11, 1962 J. E. GALAJDA, JR

DRIVER AND HEATER FOR DISC OXYGENATOR.

4 Sheets-Sheet 2 Filed June 18, 1959 SQ mE NE Q3 John E. Gala do, Jr:

1N VEN TOR.

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mdfiuwy 259m J. E. GALAJDA, JR

DRIVER AND HEATER FOR DISC OXYGENATOR Sept. 11, 1962 4 Sheets-Shee'h 3 Filed June 18, 1959 John E. Gala Zia, Jr:

LNVENTOR.

Sept. 11, 1962 J, E, GALAJDA, JR 3,053,254

DRIVER AND HEATER FoR" DISC OXYGENATOR Filed June 18, 1959 Sheets-Sheet 4 John E. Gala d0, Jr

3 1N VEN TOR. E BY.

United States Patent 3,053,254 DRIVER AND HEATER FOR DISC OXYGENATDR John E. Galajda, IL, 35206 Center Ridge Road, North Ridgeville, Ohio Filed June 18, 1959, Ser. No. 821,229 11 Claims. (Cl. 128-214) This invention relates to a machine for quickly and safely heating large volumes of liquid and has particular utility in heating blood.

During the process of complete or partial circulatory by-pass of the heart and lungs during surgery for circulatory diseases, or as a support to treatment of cardiopulmonary diseases, the rotating disc oxygenator has proved to be safe and valuable. However, the blood is subjected to cooling as it passes through necessary large tubing, pumps and the oxygenator unit. The oxygenator especially is a source of substantial cooling of the blood. Depending on blood flow rates, up to five liters of cold oxygen, carbon dioxide and anesthetic gases may pass through the oxygenator each minute. To offset this loss of heat, it was thought advisable to pre-heat the gases passing into the oxygenator. Tests have shown that although heat loss may be substantially reduced, it is a poor means of elevating or controlling blood temperature because of the heat differences in specific heats. There is also the explosion hazard involved in heating anesthetic gases mixed with oxygen.

Initial attempts to heat the blood in the oxygenator usually employed a resistance wire wound around the oxygenator bottle so that the blood is warmed by conduction through the glass side wall of the bottle. Like all methods attempting to heat blood through the glass bottle, including infra-red heat, the surface available for heat transfer is smaller than the cooling surface presented by the discs in the cool atmosphere and the heat loss is greater than can be satisfactorily handled. The result is as follows: Either the temperature of the blood during the by-pass is considerably below normal, or, excessive heating of the cylinder will maintain a normal temperature with excessive platelet destruction, hemolysis, and the collection of fibrin on the bottle.

This invention provides means by which to apply heat to the rotating discs in order to obtain multiple advan tages. The first is that by heating the surface area of the discs, the area of heat intake itself is greatly increased. Further, it is possible to heat larger volumes of blood more safely, because of the increased surface area, with a lower temperature gradient. Secondly, since the heat transfer will take place at the surface where gaseous exchange is taking place in the blood as well as in the immersed portion of the discs, the problem of dissolving gases coming out of physical solution with temperature rise is minimized. Most other oxygenating systems warm the blood after the gaseous exchange has taken place with the result that tiny air bubbles are produced in the heater and may be carried through the circulatory system of the patient with deleterious effects. The process of heating blood after gaseous exchange has taken place and with the resulting change in the solubility of the gases, espe- 'icially carbon dioxide, results in shifting pH. This problem can be rectified by the machine in accordance with this invention.

The convoluted discs of this machine, in order to give maximum surface area for heat transfer and gaseous exchange without creating undue turbulence and bubbling, are the parts of the machine which are heated.

The principal object of the invention is to provide a disc oxygenator which is safer and more satisfactorily operative than prior disc oxygenators and made so by virtue of the construction of the heating system of the disc oxygenator. The heat is preferably introduced into the system by means of the discs, and this may be the sole agents for heating of the blood or may be used in combination with heat applied from the exterior of the cylinder in which the discs are rotatable.

Another object of the invention is to provide an oxygenator system which is so arranged as to always maintain all phases of the operation under the control of the operator at one location so that the operation of the oxygenator may be monitored at all times by one person.

These, together with other objects and advantages which will become subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a largely diagrammatic view showing the controls and operating devices for a disc oxygenator construction in accordance with the invention, the oxygenator being shown in longitudinal cross-section.

FIGURE 2 is an enlarged fragmentary sectional view of the oxygenator unit together with the means coupling the oxygenator unit rotor with the drive mechanism therefor.

FIGURE 3 is an enlarged fragmentary sectional view showing the end of the oxygenator opposite to that shown in FIGURE 2.

FIGURE 4 is a vertical, transverse sectional view taken on the line 4-4 of FIGURE 2.

FIGURE 5 is an end view of the oxygenator from the right end of FIGURE 1.

FIGURE 6 is an end view of the oxygenator unit showing the end opposite to that in FIGURE 5.

FIGURE 7 is an enlarged fragmentary sectional view showing a portion of the electrical coupling between the heater in the disc oxygenator and the means to energize the heater.

FIGURE 8 is an enlarged sectional view taken on the line 88 of FIGURE 2.

FIGURE 9 is a fragmentary elevational view showing the end of an. emergency crank to be used in case of power failure for manually actuating the rotor of the disc oxygenator.

In the accompanying drawings there is an oxygenator unit 19 together with an actuating and control means 12 by which to control the operation of unit 10. The specific construction of the oxygenator unit 10 will first be considered. It is made of a cylinder 1 preferably of glass, for instance, Pyrex. End walls 16 and 18 are connected by bolts 20 to the ends of the cylindrical side wall 14. Outflow tube 22 is connected with outlet nipple 24, and the inflow tube 26 is connected with inlet nipple 28 in end wall 16. Tube 30 is connected with nipple 32 in wall 16, and tube 30 is adapted to connect with the bubble trap (not shown) and other tubes and equipment which are not shown and which are conventionally used with ordinary disc oxygenators. Oxygen line 34 is connected with an inlet fitting 36 in wall 16. Heat exchanger 38 which constitutes a part of the invention is located in the operating means 12 of cabinet 40 to serve two purposes. The first is to cool the electrical equipment in cabinet 40, especially the motors, and the second is to pre-heat the oxygen by having the oxygen inlet line 34 arranged in heat exchange relationship with heat exchanger 38.

Wall 18 has a vent 42 connected therewith. It also has a heat measuring device 44 mounted therein from which electrical conductors 46 and 48 extend. Arterial sample tube 50 is connected with device 44, and there is bearing 52 in wall 18 aligned with bearing 54 in wall 16. The oxygen inlet 36 has an orifice tube 56.connected there- C) with and extending the full length of the unit for an even distribution of oxygen during rotation of rotor 58.

Rotor 58, see FIGURES 2 and 3, constitutes an important part of unit 19. It is constructed of a hollow shaft 66 having a spindle 62 on the axis of rotation thereof and at one end. The spindle is mounted for rotation in bearing 52, and the adjacent end 64 of shaft 61) is externally threaded to receive tightening nut 66. The tightening nut bears against the hub 68 of disc 76, and the hub portion of disc 76 bears against an annular spacer 72 on hollow shaft 66. All of the discs and spacers are constructed similarly, and they are arranged parallel to each other on shaft 60. The end spacer 74 (FIGURE 2) is welded or otherwise fixed onto shaft adjacent to but slightly spaced from bearing 54- which mounts a part of shaft 66 for rotation. A heat conductive sleeve 76 is mounted in hollow shaft 66. Sleeve '76 is made of metal, and there is an electrically insulating sleeve 78 also located in shaft 60 and bearing against one end of the heat conducting sleeve 66. The spacers 72 and 74, shaft 60, and oxygenator discs 71) are made of heat conducting material, for instance, anodized aluminum, silver or chromium plated copper or silver alone. The discs are coated with a non-wetting substance such as a suitable silicone resin. Electric resistance heater 80, for example, a ceramic tube provided with electric resistance wire 84 is in sleeve 78. Resistance wire 84 extends into ceramic tube (FIGURE 7) 82 and forms an elongate closed electrical loop to heat the discs 70. The heat emanates from the axis of rotation of the rotor 58 and extends outwardly from the disc hubs 68 to the peripheries of the group of discs.

Typical disc is not flat. The hub portion 68 is flat, and the disc is formed with concentric semi-cylindrical (in cross-section) ribs 85 to increase surface area and provide for more complete heating with less foaming.

Cabinet 46 houses the means for driving rotor 58. This means consists, see FIGURE 1, of electric motor which drives shaft 92 carried by bearings in cabinet 40. One end of shaft 92 projects outwardly of the cabinet and there is a part 94 of the coupling thereon by which crank 96, see FIGURE 3, may be attached through the use of the other part 98 of the coupling. The crank is an emergency device to rotate shaft 92 in case of power failure or loss of torque or for any other reason. Output shaft 100 of motor 90 has an air circulating impeller 101 and is drivingly connected to shaft 92 by means of mitre gears 162 and 104 which are secured to shafts 100 and 92, respectively. Voltage regulator 106 is mounted in cabinet 46 and is operatively connected with a power source by means of lines 108 and 110 having switch 112 therein. The power source is also connected with temperature indicating relays 116 and 118, the latter also being mounted in cabinet 4-6. Temperature indicator 116 is connected with conductors 46 and 48, While temperature indicator 118 is connected by conductors 12ft and 122 to a temperature sensing unit 124- engaged with shaft 60 on the exterior of unit 16 and suitably supported, for instance, by mounting bracket 128 which is attached to wall 16 of the unit 10.

The power lines 108 and 119 extends to a switch 128, and additional lines 139 and 132 extend from the switch and to temperature indicating relays 116 and 118, which are conventional in nature, and to brush assembly 138 (FIGURE 8). The brush assembly is made of a pair of spring metal contacts 140 and 142 attached to a support 144- in the cabinet 46, together with a pair of slip rings 146 and 148. The slip rings are disposed on insulating sleeves 150 and 152 attached to the surface of shaft 92. Conductors 158 and 160 are secured to the slip rings and extend through an opening 162 in shaft 92 and pass through an insulating sleeve 164 disposed in the hollow shaft 92. These conductors (see FIGURE 2.) extend into a rotary cage 168 attached to shaft 92 on the exterior of cabinet 40. As is evident from inspection of FIGURE 2, there is a bearing 169 in the wall of cabinet 40 through which shaft 92 extends and adjacent to which rotary cage 163 is located. Drive pin 170 is secured to the rotary cage and is disposed in a notch 172 of drive plate 174. The drive plate is secured, for instance, by set screw 176, to the end of shaft 66, whereby the drive plate 174, drive pin 17% and rotary cage 168 establish a drive connection between shaft 96 and the rotor 53 of unit 10.

A rotary plug 186 and socket 182 establish electrical continuity between the heater 8t and conductors 161) and 153. For this construction, attention is directed to FIGURE 7. Rotary plug has a pair of conductors 189 and 196 extending axially or essentially axially through cylindrical plug body 192. Conductor 190 is attached to the terminal ball 194- of the rotary plug, and conductor 19% is attached to rotary collar 196 of the plug. The ball and collar are held separated by means of an insulating spacer 196, and collar 196 is spaced from the balance of the body of the plug by means of another insulator 269. Conductors 189 and 190 are mounted in an insulating sleeve 292 in the plug body, and the inner end of the plug body has an enlarged threaded part 294 threadedly received in the internally threaded end of shaft 6%). Insulated terminals 266 and 268 are at the inner ends of the enlarged part 204 of the plug body, and they have the heater wire 84 connected therewith.

The socket 182 is made of two spring fingers 216 and 212 which are mounted on insulating blocks 214- and 216. The insulating blocks are secured to a bearing retaining nut 226 by which bearing 222 of cage 168 is supported for reception of the plug 180. The spring fingers 210 and 212 have conductors 158 and 160 secured thereto in order to establish electrical continuity for the heating system of the oxygenator. It is understood that by virtue of the construction and circuit described, the rotor of unit 19 is heated for the purpose of heating the rotor in the oxygenator unit. Further, the rotor is capable of being rotated by torque from motor 96'. In order to monitor the rotation of the rotor 58 at all times, a tachometer signal generator 236 is mounted in cabinet 46 and is driven by mitre gearing 231 and 232 connected with the tachometer shaft and the shaft 92. A readout tachometer indicator 234 is connected by Wiring to the tachometer signal generator.

The use and operation of the oxygenator is now deemed evident. Upon operation of the control switches 112 and 128 and setting of the voltage regulator 106, the oxygenator unit is caused to have its rotor heated and also rotated. Temperature control is essential, and therefore the contents of the unit 16 are exposed to the temperature sensing device 44 at all times, and the same holds true for the application of heat. The sensing device 124 taken in conjunction with the temperature indicating relay 113 enables the operator to observe the quantity of heat being applied to the blood by way of the shaft 60.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

What is claimed as new is as follows:

1. A disc oxygenator comprising a housing provided with an inlet and outlet for liquid together with an inlet for oxygen, a rotor shaft in said housing, a plurality of discs carried by said shaft, said shaft and discs being mounted in said housing for successive immersion and emersion of said discs in the liquid upon rotation of said shaft, a heater carried by and in heat exchange relation with said shaft to heat said discs by heat conduction from said shaft.

2. The combination of claim 1 wherein said discs have an annular circumferentially extending rib formation upon an annular face of each, said rib formation consisting of a series of equidistantly spaced ridges each projecting laterally from said annular face.

3. The combination of claim 2 wherein each disc includes an annular hub disposed within said ridges and is apertured for reception upon said shaft, annular spacers received on said shaft and in direct heat exchange relation therewith, each disc having its hub received and embraced between a pair of spacers, said hubs and spacers being disposed in direct heat exchange contact with each other.

4. The combination of claim 1 including driving means connected to said shaft, means connected to said oxygen inlet for preheating the oxygen passing therethrough by heat generated by said driving means, temperature sensing means connected to said shaft exteriorly of said housing and indicating the quantity of heat being introduced into said housing through heat exchange with said shaft.

5. The combination of claim 1 wherein said discs have a series of circumferenti-ally extending corrugations for increasing their surface area, said corrugations comprising alternate continuous ridges and valleys, adjacent ridges being equidistantly spaced throughout their circumferential extent.

6. The combination of claim 1 wherein said oxygen inlet includes a conduit within said housing having outlets, said outlets being each disposed adjacent the periphery of a disc for applying oxygen to the liquid film carried by said disc during its rotation.

7. The combination of claim 1 including driving means connected to said shaft, means connected to said oxygen inlet for preheating the oxygen passing therethrough by heat generated by said driving means.

8. The combination of claim 7 including temperature sensing means thermally connected to the interior of said housing and indicating the temperature of the liquid contacts of said housing.

9. A disc oxygenator comprising a cylinder having means for circulating a liquid therethrough and maintaining a liquid level therein, means for admitting oxygen into said cylinder into contact with said liquid and for oxidizing the latter, a rotor in said cylinder including a shaft and a plurality of discs carried by said shaft in axially spaced relation thereon, means rotatably mounting said shaft axially of said cylinder for successive immersion and emersiou of areas of said discs in the liquid in said cylinder for oxidizing said liquid, heating means carried by and in heat exchange relation with said shaft and to heat said discs, a cabinet, operating means in said cabinet including an electric motor and a shaft assembly connected thereto, connecting means secured to said shaft assembly and to said shaft for rotating the latter.

10. The combination of claim 9 including a heat exchanger in said cabinet and receiving heat input from said electric motor, an oxygen supply conduit in said cabinet in heat exchange relation with said heat exchanger and communicating with said oxygen admitting means for preheating the oxygen supplied to the latter.

11. The combination of claim 10 wherein said heating means comprises an electrical resistance heater disposed within said shaft, said shaft assembly including a slip ring assembly, means in said cabinet for supplying electric current to said slip ring assembly, said connecting means including a plug and socket electrically connecting said slip ring assembly to said resistance heater.

References Cited in the file of this patent UNITED STATES PATENTS 254,003 Gontard Feb. 21, 1882 1,560,603 Niece Nov. 10, 1925 1,587,840 Kilmer June 8, 1926 2,110,621 Cohen Mar. 8, 1938 2,380,346 Thomlinson July 10, 1945 2,601,519 Hardy et al. June 24, 1952 2,624,552 Rose Jan. 6, 1953 OTHER REFERENCES Cross et al.: Evaluation of a Rotating Disc Type Reservoir-Oxygenator, Proceedings of the Society for Experimental Biology and Medicine, volume 93, No. 2, Nov. 1956, pages 210214 (pages 210-212 relied on). (Available in Science Library.)

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