US2263162A - Apparatus for preventing contamination during surgical operations - Google Patents

Description

Nov. 18, 1941. J, F, COLLINS 2,263,162

APPARATUS FOR PREVENTING CONTAMINATION DURING SURGICAL OPERATIONS Filed Nov. 18, 1959 4 Sheets-Sheet 1 13 l g- 3 MASTER U LTRAVIOLET CONTROL BOARD.

MANUAL $4 INVENTOR ATTO R N EY Nov. 18, 1941. J. F. COLLINS 2,253,152

APPARATUS FOR PREVENTING UONTAMINATION DURING SURGICAL OPERATIONS Filed Nov. 18, 1939 4 Sheets-Sheet 2 m I m 1 R Y w I O a. E E w W W x J. u, w m n w 1 l A P Eu 0 27 K n a Elia J a E H m? W m 1! I 1 FM! W WVVVVV VVVVVVNS Z J w a I 5 w z. a .M 2 Z M Z00 5 W a a a w W 1/ \& I w I a w /W\\\\\\\ M u a 3%: 7 f W L I Nov. 18, 1941. J. F. COLLINS 2,253,162

APPARATUS FOR PREVENTING CONTAMINATION DURING SURGICAL OPERATIONS I Filed Nov. 18, 1939 4 Sheets-Sheet 5 INVENTOR J". F: cog/M Nov. 18, I 19 J. COLLINS ONS APPARATUS FOR PREVENTING CONTAMINATION DURING SURGICAL OPERATI Filed Nov. 18, 1939 4 Sheets-Sheet 4 INVENTQR \7'. F'- coll/A45 BY WWW L ATTORNEY 3 Ta m a a a .w 1 M w m m 2 4 m W .m m C 0 z x z 3 f m0 Patented Nov. 18, 1941 APPARATUS FOR PREVENTING CONTAMINA- TION DURING SURGICAL OPERATIONS Joseph F. Collins, Flushing, N. Y., assignor, by mesne assignments, to Westinghouse Electric and ManufaoturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 18, 1939, Serial No. 305,070

16 Claims.

ing above and below the beneficial region of the spectrum. This has resulted in practical employment of ultra-violet generators, particularly in hospital operating rooms, being considerably handicapped because of the heat generated by the longer radiations and the fact that such radiations jeopardized both the patient and operating team to such an extent as to substantially offset the benefits derived from the beneficial radiations.

An ultra-violet generator isnow on the market which is manufactured under the trade mark Sterilamp and comprises a lamp operating at a temperature of but approximately 4 F.

above room temperature and wherein overeighty per cent of the emitted radiations are confined to the most highly bactericidal and therapeutical region of the spectrum at about 2537 Angstrom units. The advent of this particular type of lamp has eliminated the objectionable results inherent in prior type ultra-v10- let generators and has made possible the practical employment of ultra-violet radiations during a surgical operation, to prevent contamination of an incision due to air-borne micro-organisms, and promote rapid post-operative healing through the therapeutical effect of the beneficial radiations.

In my copending applications, Ser. No. 277,138

and Ser. No. 277,139, both filed June 3, 1939, a hospital operating room unit is shown which is adapted to be supported above the operating table so that both visible and ultra-violet radiations are projected toward the patient while disposed upon the operating table, and the present invention constitutes an improvement on that shown in these above noted copending applications.

It must be conceded that under modern methods of sanitation and ventilation the operating room of substantially all hospitals is clean and uncontaminated, and tests unequivocally show practically no contamination in the air oron the walls and floors so long as the room is unoccupied. As soon, however, as the door is opened and the patient brought in with the attendin nurses and internes, contamination appears in the remote corners of the room, carried there by the air currents. Actual tests show the peak of this contamination is reached during the transfer of the patient to the operating table and the turbulence caused by the activity in the room attending the preparation for the operation. When this activity ceases, contamination decreases only to rise again when the surgeon and his staff enter the room; and, although this second rise in contamination may not be as high as the intial one, nevertheless, its level apparently remains constant throughout the operation.

Due to this resulting contamination of a previously uncontaminated room, no part of the operating room can be considered free of contamination or unimportant, since eddy currents play an important part in creating pockets of contamination and in causing micro-organisms which ordinarily remain floating in air to come in contact with moist surfaces and adhere thereto. Moreover, an occupant of the room in walking past a pocket will all toofrequently cause an eddy current to suck the contamination from the pocket with themicro-organisms following the movements of the occupant borne by these currents.

A different condition exists over the operating table. During the operation the operating team surrounds the incision and their gloved hands, instruments and the incision itself, are all exposed to a settling of bacteria which have escaped through their face masks. Again eddy currents caused by the movement of the hands of the operators will cause many organisms, which would ordinarily remain suspended in air, to be propelled against and adhere to moist surfaces. To eliminate these hazards it is necessary to not only subject the operative field to highly bactericidal ultra-violet radiations as shown and described in the above noted pending applications, but to also irradiate the room during occupancy to destroy organisms fanned into circulation from contaminated pockets.

Moreover, it is essential to install the ultraviolet generators in such manner that their effectiveness as a bactericidal and therapeutical agent is a maximum while controlling and limiting the intensity of radiation fallingon any unprotected tissue to a safe tissue tolerance exposure. In addition, it is of primary importance to maintain a controlled intensity level throughout the duration of an operation, and in order to assure adequate protection, uniform distribution of radiation throughout the area to be protected is essential.

It is accordingly an object of the present invention to provide a method for lowering the contamination level of a hospital operating room during occupancy by subjecting substantially the entire room to ultra-violet radiations of a highly bactericidal wavelength.

Another object of the present invention is the provision of an ultra-violet apparatus for irradiating substantially the entire area of a hospital operating room to prevent contamination from air-borne micro-organisms to the incision in a patient during the performance of a surgical operation.

Another object of the present invention is the provision of an. ultra-violet. apparatus wherein substantially the entire area of a hospital operating room, while occupied by a surgical team during an operation, is subjected to radiations of maximum bactericidal and therapeutical effectiveness to prevent contamination of an incision in a patient and the intensity of the radiations is maintained within safe tissue tolerance exposure limits.

Another object of the present invention is the provision of an ultra-violet apparatus wherein substantially the entire area of a hospital operating room is subjected to radiations of maximum bactericidal. and therapeutical effectiveness and the intensity of the radiations is maintained constant throughout the life of the ultra-violet generators. 7

Another object of the present invention is the provision of an ultra-violet apparatus wherein substantially the entire area of a hospital operating room, as well as the patient and operating team, is subjected to radiations of maximum bactericidal and therapeutical effectiveness and the intensity of the radiations so controlled as to be maintained at a constant level or automatically varied as desired and over a predetermined period of time.

A further object of the present invention is the provision of an ultra-violet apparatus wherein substantially the entire area of a hospital operating room, as well as the patient and operating team, is subjected to radiations of maximum bactericidal and therapeutical effectiveness and wherein the dosage or destructive efiect to bacteria, which represents the product of the intensity and time of exposure, is preset and automatically controlled.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawings wherein:

Fig. 1 is a perspective view of a typical hospital operating room which is shown provided with ultra-violet apparatus in accordance with the present invention;

Fig. 2 is an elevational view of the master ultra-violet control panel shown mounted on the wall of the operating room of Fig. 1;

Fig. 3 is a fragmentary view partly in section showing a portion ofthe control panel of Fig. 1 looking at the front of the panel;

Fig. 4' is a sectional view taken on the line IV-IV of Fig. 3 showing the tapering control mechanism;

Fig. 5 is a view partly in elevation and partly in section as taken on the line VV of Fig. 3,

showing the time control mechanism forming a part of the apparatus of the present invention;

Fig. 6 is a sectional view on an enlarged scale of the tapering control mechanism of Fig. 4;

Fig. 7 is a sectional View taken on the line VII-VII of Fig. 4;

Fig. 8 is a sectional view taken on the line VIIIVIII Of Fig. 5;

Fig. 9 is a fragmentary view of still another portion of the control panel of Fig. 2 looking at the front of the panel;

Fig. 10 is a sectional view taken on the line X--X of Fig. 9;

Fig. 11 is a schematic diagram of the various electrical circuits forming a part of the apparatus of the present invention;

Fig. 12 is a schematic diagram of a further portion of the electrical circuits forming a part of the present invention, and

Fig. 13 is a graphic illustration showing the safe dosage of ultra-violet radiations which can be administered for various periods of time.

Referring now to the drawings in detail, a typical hospital operating room is shown in Fig. 1 provided with an operating table 5 for supporting a patient during a surgical operation. Suspended from the ceiling 6 is a lighting unit shown generally at 1, such as described and claimed in my above noted copending application, Ser. No. 277,139, and since such unit per se forms no part of the present invention, it is believed unnecessary to describe the same in detail. It should sufllce to say that visible light is projected in the form of an inverted cone from a source surrounded by a Fresnel lens 8 so as to concentrate the light beam at the level of the top of the table 5.

A pair of semi-circular ultra-violet lamps II are supported about the perimeter of the lighting unit I so that the invisible ultra-violet radiations are likewise projected in the form of a cone substantially coinciding with that of visible light. These ultra-violet lamps are of the Sterilamp type which operate at about 4 F. above room temperature and the radiations emitted are substantially monochromatic with over of the radiations lying within the highly bactericidal region of the spectrum at about 2537 Angstrom units. The intensity of the ultra-violet radiations, as disclosed and claimed in the above mentioned copending application, is set by a manual control conveniently located on the wall to give a desired intensity from the lighting unit 1 at a predetermined height above the operating table. Since the intensity of the radiations naturally varies with distance from the source, the unit I is provided with means shown at H], which automatically operates to vary the intensity of the ultra-violet radiations from the fixed setting as the lighting unit 1 is moved perpendicularly toward or away from the table 5.

This arrangement accordingly insures a constant safe intensity of highly bactericidal radiations at the level of a patient during a surgical operation so that exposed viscera is not affected such as to otherwise cause post-operative adhesions to the patient. Although the unit as described in my above noted application is effective to destroy air-borne micro-organisms exhaled by the operating team, it is desirable to surround the patient and operating team by a wall formed by a barrage of high intensity bactericidal ultraviolet radiations to thus destroy micro-organisms carried by eddy currents of air which follow various movements of occupants of the operating room.

To this end the operating room is provided with a plurality of auxiliary units l2, as shown in Fig. 1, which may be supported on the wall or suspended from the ceiling, depending upon the size of the operating room, with the ultra-violet lamp 9, of similar type as those carried by the lighting unit I, being about eight feet from the floor. These auxiliary units l2 are disposed in a rectangle or quadrangle, again depending on the size of the room, which has its axes corresponding to the operating table with the number of units computed on the basis of the total floor area and electrically connected to two or more supply circuits.

All of these auxiliary units l2 are of identical construction and comprise a spider secured to the customary outlet box and concealed by a canopy l3. A stem I4 is suspended from the spider (not shown) which supports a yoke It. A terminal box l6 containing two sockets (not shown) and a small transformer I1 (Fig. 11) having its secondary winding l8 connected in series with the lamps 9, is disposed at each end of the yoke I and spaced approximately thirtysix inches apart so as to receive two ultra-violet lamps 9 which have an effective ultra-violet emitting length of about thirty inches. At the junction of the stem l4 and yoke Hi the latter is enlarged to receive a compensator such as a rheostat l9 (Fig. 11), which has a control knob 1 for operating the rheostat l9.

In order to insure the generation of ultra violet radiations of the requisite intensity or potency to destroy air-borne micro-organisms during the entire life of the lamps 9 in the auxiliary units l2, the control knobs 2|] of each unit are rotated to set the rheostat l9 so that when initially installed the intensity of each lamp 9 is restricted to of their intensity and thus equivalent to one lamp of 100% the required lethal intensity. The lamps II of the central unit are similarly set by initial adjustment of the control I0. As the lamps age with a falling off of their radiation effectiveness, which preferably is checked about once a month, the rheostat I9 of each auxiliary unit is adjusted until the recording meter used for testing again indicates standard or 100% intensity. In this manner the surgeon is assured of a constant proper intensity of radiations which, due to the positioning of the auxiliary units, form a barrage or wall surrounding the operating team. Naturally the auxiliary units are not effective in the area directly over the patient as their radiations are screened by the operating team; but, as before noted, the lamps ll carried by the central lighting unit 1 protect such area.

Despite the fact that the intensity of the radiations from the lamps ll carried by the central lighting unit 1 may be manually controlled, as described in the above mentioned copending application, and the fact that the auxiliary units l2 may be set for a desired intensity by the rheostats l9, it frequently becomes necessary to vary the intensity of all the generated ultra-violet radiations, or at least some of these radiations, to correspond to the safe tolerance for the duration of an operation.

For example, Fig. 13 is a graphic illustration computed from numerous curves taken from a tual cases wherein the abscissa represents exposure time in minutes required for the destruction of various organisms at difierent intensities. The ordinate represents intensity of ultra-violet radiations expressed in "clicks per minute, as hereinafter more fully described. This chart accordingly shows the safe intensity dosage for different lengths of time with the shaded area indicative of the dosage or radiation limits for safe tissue tolerance, whereas outside of the shaded area dangerous intensities result which might cause harmful adhesions.

In addition to maintaining a predetermined safe intensity for a definite period of time, it is frequently desirable to have the intensity taper gradually from a maximum to a minimum during the period of the operation; and still further, since the ultra-violet radiations from the lamps of the type shown at 9 and I l have a high therapeutical effect, in some instances the surgeon may desire to subject the patient to a preselected dosage.

To meet these various requirements, a master control panel 22, as shown in Figs. 1 and 2, is

mounted at a convenient height in a room adjacent the operating room, or preferably on the wall of the operating room, as can be seen in Fig. 1. This master control panel may be considered as divided into four vertical sections as well as three horizontal sections, as shown in Fig. 2. The three horizontal sections comprise a plurality of switches for controlling the ultraviolet lamps ll carried by the central lighting unit 1 and the ultra-violet lamps 9 supported by the auxiliary units l2 which latter, as before noted, generally requires not more than two electrical circuits, although for the sake of simplicity one of the circuits will be referred to hereinafter as the wallcircuit or on walls, while the other circuit will be referred to as the ceiling circuit or on ceiling.

The first vertical section, reading from left to right in Fig. 2, comprises a manual rotatable control knob 23 and stationary graduated dial 24 for varying the intensity of the ultra-violet radiations generated by the lamps ll of the central lighting unit I and the lamps 9 of all the auxiliary units l2, which intensity ranges from zero to the maximum as determined by the automatically operable device I0 (Fig. 1) and the various rheostats l9 of the several auxiliary units l2. The second vertical section comprises a tapering rotatable control knob 25 and a stationary graduated dial 26, and switches 21, 28, and 29 of the horizontal sections are rotatable either clockwise or counterclockwise from their off position to connect the ultra-violet lamps 9 either to the manual or tapering control.

The third vertical section comprises a time rotatable control knob 30 and stationary graduated dial 32 while they fourth vertical section includes a graduated rotatable dial 33, the indicia of which registers with a stationary pointer 34. Switches 35, 36, and 31 of the horizontal sections are rotatable from their off position in the same manner as the remaining switches 21, 28, and 29 to connect the various ultra-violet lamps either to the time or dosage control as desired. Each of the four vertical sections are provided with signal lamps 39 which may be disposed in back of a bulls-eye provided in the panel 22 to give a visual indication as to the particular control under which the lamps, II are energized at a given moment.

By reference to Fig. 11 it will be noted that the manual control knob 23 (Fig. 2) is connected to ashaft 39 carrying three contact arms All, 42, and .3 adapted to simultaneously contact the resistance winding of respective rheostats 44, 4.5, and 46 with the mechanical construction being substantially identical to that shown in Fig. 4, as hereinafter described. When the respective switches 21, 28, and 29 are rotated counter-clockwise, as shown in Fig. 2, which corresponds to the raised position in the schematic diagram of Fig. 11,- the rheostats are thus connected in the energizing circuit for the primary winding of the transformers I! of the auxiliary units l2, as well as to the. primary'winding of a transformer 41 for energizing the ultra-violet lamps ll carried by the central lighting unit I.

For example, electrical energy is supplied from the customary source of domestic potential Ll- L2, with one side of the source Ll being connected by a conductor 48 and normally closed contacts of three relays 49, 50, and 52 to one side of the primary winding of both transformers H for energizing the respective circuits for the auxiliary units [2, as well as the primary winding of the transformer 41 which energizes the lamps ll of the central unit 1. The other side of the source L2 is connected by a conductor 53 to the contact arms 40, 42, and 43 of the respective rheostats 44, 45, and 46, and the resistance windings of each of these rheostats are connected by respective conductors 54, 55, and 56 and the arm of switches 21, 28, and 29 to the remaining end of each of the primary windings of the transformer 41 and both transformers H.

It will also be noted from Fig. 11 that one terminal of each of the signal lights 38, shown immediately above the respective switches 21, 28, and 29, are connected to the conductor 48 and thus to one side of the source Ll. Each of the switches 21, 28, and 29 is shown provided with contact bars 51 insulatingly supported on the top and bottom of the arms of these switches, and in the upper position thereof the top bars complete a connection between a conductor 58 extending from the source L2 and each of the remaining terminals of the upper signal lamps 38.

Accordingly, when it is desired to manually set the intensity of the lamps 9, carried by all the auxiliary units I2 and the lamps ll of the central lighting unit 1, to a desired value ranging from zero to the maximum as determined by the respective rheostats l9 and the device II], it is only necessary for the operator to rotate the manual control knob 23 until it registers with the indicia on the dial 24 corresponding to arbitary units of intensity computed as hereinafter described. Having set the manual control to the preselected intensity, which thus simultaneously adjusts the rheostats 46, 42, and 43 to include a definite resistance in the energizing circuits for both transformers l1 and the transformer 41, the switches 21, 28, and 29 are then rotated counter-clockwise, as shown in Fig. 2 and corresponding to an upward movement in Fig. 11, thus completing the circuits to the transformers and to the upper signal lights 38 upon closure of a main line switch (not shown) for the source Ll-- -L2.

As previously mentioned, it is frequently desirable in'cases of surgical operations of comparatively long duration to have the intensity of the ultra-violet radiations gradually decrease from a maximum setting at the beginning of the operation when contamination is greatest, which decrease will be herein referred to as tapering. In instances of this kind the tapering control knob 25 is depressed for reasons later herein described and rotated until it likewise registers with the indicia carried by the stationary dial 26 which represents arbitrary units of intensity. In Fig. 4 the mechanical construction of the tapering control is shown which, as previously mentioned, is substantially identical to the construction of the "manual control. As shown in this figure, the control knob 25 is secured to a shaft 59 suitably journalled in a pair of upwardly projecting plates 60 and 62 forming an integral part of a supporting bracket 63 secured to the back of the panel 22. The shaft 59 carries three contact arms 64, 65, and 66 adapted during rotation to engage the turns of stationary rheostats 61, 68, and 69 and as thus far described, the tapering control is identical to the manual control.

Unlike the manual control, however, the tapering control is provided with a cam 10 carried by the shaft 59 and during the greater portion of its rotation, the cam 19 maintains closure of a pair of contact terminals 12 and 13 constituting a time limit switch for the transformer circuits, as can be better appreciated from Fig. 7. In order to automatically rotate the shaft 59, a self-starting synchronous electric motor 14 (Fig. 3) is disposed in back of the panel 22. The motor shaft is provided with a pinion gear 15 meshing with a larger gear 16, which latter gear in turn is affixed to a pinion gear 11 carried by a short shaft 18 suitably journalled in brackets or the like (not shown) in the rear of the panel 22. Meshed with the pinion I8 is an intermediate gear 19 which meshes with a gear 86 affixed to the shaft 59 of the tapering control, so that upon energization of the motor 14, the shaft 59 and all parts carried thereby are rotated through the reduction gear train formed by these various gears.

By reference now more specifically to Fig. 6, it will be noted that the tapering control is provided with a clutch arrangement to allow setting of the control without interference from the gear train which would otherwise act as a look. This clutch comprises a plate 82 provided with a recessed annular portion 83 into which the end of the shaft 59 partially protrudes and an elongated portion, which may be considered for present purposes as an extension of the shaft 59, passes through a bearing portion 84 of the bracket 63 and the panel 22, to which the control knob 25 is aflfixed.

A coil spring 85 is disposed between the projecting plate 62 and the clutch plate 82 thus normally to maintain frictional engagement with the driven gear 80. A slot 86 is provided in the recessed annular portion 83 of the clutch plate 82, and a pin 81 protruding from the shaft 59 engages the slot to form a driving connection between the clutch plate and the shaft 59. When setting the tapering control, it is only necessary to depress the control knob 25 and rotate the same to align with the desired indicia as previously mentioned. Depression of the knob 25 compresses the coil spring 85, allowing the clutch plate 82 to move to the left, as shown in Fig. 6, by sliding further upon the shaft 59, with the end of the latter and the pin 81 protruding further into the recess 83 and slot 86, thus releasing the frictional engagement between the clutch plate and gear 80. Due to the driving engagement between the slot 86 and pin 81, the shaft 59 rotates the contact arms 64, 65, and 66 to the selected turns of the respective rheostats 61, 68, and 69 to include the desired amount of resistance in the circuits.

Again referring to Fig. 11, it will be noted that electrically the tapering control is substantial- 'ly identical to that of the manual control. After setting the tapering control to the desired intensity, as indicated on the dial 26, the three switches 21, 28, and 29 are moved from their off position in a clockwise direction as viewed from Fig. 2. This rotation of these switches corresponds to a downward position as viewed from the schematic diagram of Fig. 11. When the shaft 59 has been rotated by the control knob as above mentioned, the cam 19 will be in its normal position so as to cause closure of the contacts 12 and 13. The contact 12 is connected to one side of the source of supply L2, and the other contact 13 is connected, by a conductor 88, to each of the contact arms '64, 65, and 66 of the respective rheostats 61, B8, and 99. A conductor 89 extends from the winding of the rheostat 61 and through the switch 21 (now in the down position) to one side of the primary winding of the transformer 41 and, since the other end of this transformer winding is connected by the conductor 48 to the other side of the source of supply LI, the lamps II carried by the central fighting unit 1 are again energized. In a similar manner, the windings of the rheostats 68 and 69 are connected by conductors 99 and 92 and the respective switches 28 and 29 to the transformers I1, which thus energizes the lamps 9 carried by the auxiliary units I2 (Fig. 1) on the walls and.

51, and conductor 48 again complete the energiz ing circuit for these lamps. Also the electric motor 14 is now energized to cause rotation of the reduction gear train and the shaft 59, together with the rheostat contact arms 64, 65, and 66.

This motor energizing circuit extends from the source LI, through a pair of normally closed contacts 93 and 94, constituting a limit switch for'the motor circuit, through a conductor 95 to one side of the motor 14 and the motor signal lamp 39, and thence from the motor and lamp through a conductor 96- and the lower bar 51 of each of the respective switches 21, 28, and 29 to the conductor 58 extending from the source L2, thus completing the circuit from the source LI-L2.

Initially the rheostat contact arms 64, 65, and 66 are in their respective positions where little or no resistance is included in the transformer energizing circuits, as shown in Fig. 11, thus causing maximum intensity of the ultra-violet radiations from all the lamps 9 and II. As the automatic operation of the tapering control continues, the motor 14 causes rotation of the rheostat arms 64, 65, and 66, in the direction indicated by the arrows in Fig. 11, thus gradually including more and more resistance in the circarts and progressively decreasing or tapering the intensity of the emitted ultra-violet radiations from the lamps 9 and II.

The operation of the tapering control will thus continue until the rheostat arms 64, 65, and 69 have rotated to include all the resistance in the transformer energizing circuits, and rotation of the shaft 59 together with the cam 19 by this time will position the cam 19, so that a projection 91 on the contact 13 enters the reduced diameter portion 98 of the cam 19, causing the contacts 12 and 13, constituting a limit switch for the transformer circuits, to open, thus de-energizing 1 With the tapering control.

the transformer circuits and extinguishing all of the lamps 9 and II.

At the same time a cam 99 carried by a shaft I 99 is rotated by the motor 14 and reduction gear train, as hereinafter more fully described, so that a projection I92 on the contact 94 enters the reduced diameter portion I93 of the cam 99, causing the contacts 93 and 94, constituting a limit switch for the motor circuit, to open and de-energize the motor and motor signal light circuits, thus discontinuing operation of the tapering control substantially coincidentally with the completion of the surgical operation.

In addition to the controls already mentioned, the panel 22 is provided with a time control comprising the control knob 39 and stationary dial 32 having indicia representing time in minutes, which time control operates in conjunction By reference to Fig. .5 it will be noted that the mechanical construction of the time control ismechanically similar to that. of thetapering control. 1 Inother words, 'a bracket I94 is supported on the rear surface of the panel 22, and the shaft .I99 is suitably journalled in two projecting plates I95 and I95, in the same manner as described relative to the tapering control. A clutch arrangement identical to that of the tapering control is also provided for the time control which likewise has agear I91 meshing with the gear 19 of the reduction gear train, as can be seen in Fig. 3, so as to be rotated by the synchronous motor 14 simultaneously with the rotation of the tapering control.

The shaft I99 besides carrying. the cam 99, as previously mentioned, also has aifixed thereto an elongated cam I98 of slightly differentconfiguration from that of the cam 99, as shown more in detail in Fig. 8, which during rotation establishes engagement with three sets of normally open contacts I99-H9, Il2-II3, and II4--II5 to cause closure thereof, while the cam 99 causes opening of the normally closed contacts 93 and 94, as above noted. Inasmuch as the gear19of the gear train engages the gear 89 of the tapering control and the gear I91 of the time control, it can be readily appreciated that both controls operate in synchronism. Thus, if the tapering control knob 25 and the time control knob 39 are set opposite the same indicia (although one represents intensity and the other time) of their respective dials, they will rotate in unison which will result in the time limit switch for thetransformer circuits (contacts 12 and 13) opening at the same time that the time limit switch for the motor circuit (contacts 93 and 94) opens.

However, the speed of the synchronous motor 14 and the reduction gear train is such that it provides enough time for the respective controls to make one complete revolution during the time of the longest surgical operation. Since it more frequently happens that surgical operations take less time than this maximum average and the time control can be set for any desired time period up to the maximum, it can be appreciated that in the absence of privisions to the contrary, the time control would open the limit switch for the motor 14 prior to the tapering control opening the limit switch for the transformer circuits. Such operation would accordingly leave all thelamps 9 and II energized, but at the decreased intensity determined by the position of the rheostat arms 94, 65, and 96 at the moment the motor stopped rotating the gear train,

This undesired operation is prevented, however, by closure of the contacts I'09-I'I0, II2I I3, II4I I5 upon their being engaged by the cam I58. In order to place the time control in operation, the switches 35, 36, and 3'! are rotated from their off position in a counterclockwise direction, as shown in Fig. 2, which corresponds to the left as shown in the schematic diagram of Fig. 11. The construction of these switches 35, 36, and 3! is identical to the switches 21, 28, and 29; but since the former are shown in Fig. 11 in a vertical position, the conductor bars 51 will be referred to as right and left bars. Assuming that the tapering control is set, then the switches 21, 28, and 29 will be in their lower position, as viewed in Fig. 11, and the transformer circuits will be energized through the time limit switch, while the motor is similarly energized through the time limit switch for the mtor circuit upon closure of the main line switch (not shown), as previously described.

The time control assumably has been set, by release of the clutch and rotation of the knob 39, for a time period less than maximum. This means that the shaft 99, while rotating at the same speed as the shaft 59, will nevertheless rotate a less distance before opening the time limit switch for the motor circuit, leaving the time limit switch for the transformer circuits still closed. By the time the shaft I00 has rotated sufficiently to cause the cam 99 to open the time limit switch contacts 93 and 94 to interrupt the motor circuit, the cam I98 will also have rotated to cause closure of the respective contacts I69II6, II2-II3, and II4II5.

It will be noted by again referring to Fig. 11 that the respective contacts II 0, H3, and H5 are connected by a conductor II6 to one side of the source L2. Accordingly, upon closure of the contacts I99-IIO an energizing circuit will be completed to the relay 52 from the conductor II 6 through the contacts I'99II9 and a conductor I, switch (now in the left-hand position) (Fig. 11) and a conductor H8 to the winding of the relay 52, thence to the conductor 48 extending from the other side of the source LI. The relay 52 will attract its armature, thus opening its contacts and interrupting the energizing circuit for the transformer 41 despite the fact that the limit switch 'I2I3 is still closed.

Similarly, an energizing circuit for the relay is simultaneously closed which extends from the conductor H6, through contacts II2-II'3, a conductor I I9, switch 35 (also in left-hand position, as shown in Fig. 11) and a conductor I20 to the winding of relay 50, thence to conductor 48 extending from 'the source LI. The relay 50 thus opens its respective contacts, interrupting the energizing circuit for the transformer I! for the on wall circuit. Likewise, a circuit extends from the conductor H6, II4--I I5, a conductor I22, switch 31 and a conductor I23 to the winding of relay 49, and thence to the conductor 48 extending from the source LI thus causing similar operation of the relay 49 and interruption of the energizing circuit for the transformer I7 supplying energy to the on ceiling circuit.

Also, movement of the switches 35, 35, and 31 to the left, as shown in Figs. 2 and 11, will energize the signal lights 58 to the left of these switches since a circuit is completed to each of these lampsby conductor I24 extending from one side of the source LI to each lamp and through the lamps and respective left-hand bars 51 of through contacts each switch, and thence through a conductor I25 to the other side of the supply source L2.

From the foregoing it will be obvious that numerous combinations of operation of the apparatus are possible simply by the proper positioning of the various switches. If, for example, the switches 35, 36, and 31 are in their off position and the switches 21, 28, and 29 move to manual control, the latter alone will operate since these switches also operate the tapering control which cannot be selected at the same time as the manual control. By moving the switches 35, 3B, and 31 to the left to select the time control, the latter can be combined with the manual to give a desired intensity determined by the setting of the rheostats 44, 45, and 46 for a period of time in accordance with the setting of the time control.

When the various switches are in this position, it is to be noted that the tapering control plays no part in the function of the apparatus, although it does rotate with the time control. However, no circuits are completed by the tapering control as the transformer circuits are supplied directly through the rheostats 44, t5, and 4G and not through the limit switch T2l3 and rheostats 51, 68, and 69. Also, since the switches 27, 28, and 29 are in their upward position as shown in Fig. 11, they do not complete a circuit to the synchronous motor 14. Instead the motor is energized by a circuit now extending from the source LI through limit switch for motor 9394, conductor '15 to motor I4 and lamp 33, thence through conductor 96 to a junction I26 and from this junction through a conductor I2'I, left-hand bar of each switch 35, 36, and 37, and conductor I25 to the other side of the supply source L2.

The motor thus rotates until the time control operates to open the limit control for the motor 93-414 at which moment the contacts adjacent the cam I98 close to cause energization of the relays 49, 56, and 52, thus interrupting the transformer energizing circuits after the expiration of the preselected time period, in the manner above stated. If now tapering control operation is desired, the switches 35, 35, and 37 are moved to their off position and the switches 21, 28, and 29 moved to select this control. The transformers I! and 41 are now energized through the rheostats 67, 68, and 69 and the motor circuit is completed through the downward position of the switches 2?, 28, and 29. As before mentioned, when the tapering control operation alone is employed, the time control is set at maximum since it operates mechanically with the tapering control and also interrupts the motor circuit, although it completes no other circuits. The tapering control will accordingly operate to gradually reduce the intensity for a full period of the operation after which both the motor circuit and the transformer circuits are interrupted, as before explained.

To combine tapering control with time control, the switches 35, 36, and 31 are now rotated to the left to select the time control and the latter set for any desired period less than the maximum. Operation of both controls then continues until the limit switch for the motor above described. It is also obvious that by desired manipulation of the switches 21, 29, 29, 35,

36, and 31 of the control panel, the lamps II of the unit I may be selected to operate under one or more types of control, while either the on wall or on ceiling lamps of the auxiliary units 12 operate under the same or different type control as selected.

In addition to the individual and combined controls thus far described, the apparatus of the present invention includes a dosage control, as previously mentioned. This portion of the apparatus operates in response to the emanation of ultra-violet radiations of preselected intensity and is particularly applicable to therapeutic treatment of patients where a definite cumulative dosage of ultra-violet is desired.

To set the apparatus for dosage control, the rotatable dial 33 is depressed and moved to register the desired indicia, representing total units of ultra-violet radiations, with the stationary pointer 34, as shown in Fig. 2. The mechanical structure of the dosage control is substantially identical to that of the time control except that the dial 33 is rotated by a shaft 128, which also carries an elongated cam 129 engageable with a plurality of contacts 130-132, 133-134, and 135-136, as shown in Fig. 10, in th same manner as that of the time control.

The dosage control is supported on the rear of the panel 22 by a bracket 13'! to which the shaft 128 is suitably journalled and is provided with a clutch arrangement identical to that of both the tapering and time control including a pinion gear 138. By reference to Figs. 9 and 10 it will be noted that the gear 138 meshes with a gear 139 carried by a short shaft 140 journalled to th bracket 13?. A ratchet gear 142 is also rigidly secured to the shaft 149 and a rocker arm 143 is pivoted to the bracket 131 and biased by a coil spring 144. Pivotally secured to the upper end of the rocker arm 143 is a dog 145 biased by a coil spring 146, and the lower end of the rocker arm is connected by a slot and pin connection 141 to the plunger of a solenoid 148 normally biased in the projected position by a coil spring 149.

By this arrangement the shaft 1213 together withthe cam 129 and gears 138 and I39 are rotated periodically each time the solenoid 148 is energized, due to the driving connection constituting the rocker arm 143, dog 145 and ratchet gear 142, which accordingly causes successive rotation of the dial 33. In order to cause periodic energization of the solenoid 148, a portion of the dosage control is positioned in the operating room so as to be irradiated by the ultra-violet radiations from the lamps 11 carried by the central unit '1 and the lamps 9 of the auxiliary units 12, simultaneously with subjecting thepatient to these same radiations, with such portion being connected to the master control panel 22 by a flexible cable 141 and attachment plug 151 (Fig. 12).

This portion of the dosage control is shown in the schematic diagram of Fig. 12 and comprises substantially a meter for ultra-violet as described and claimed in Patent No. 2,037,925, issued April 21, 1936, to Harvey C. Rentschler. Since this portion of the apparatus per se forms no part of the present invention, it is believed unnecessary that it be herein described in detail. It should sufilce to say that it comprises a radiation responsive device, such as a photoelectric cell 150, which is subjected to the ultraviolet radiations from the lamps 9 or 1 1, as shown in Fig, 12. As the invisible ultra-violet radiations fall upon this photo-cell. a condenser 152 of preselected capacity is charged from a suitable source of electrical energy, such as a battery 153, at a rate proportional to the intensity of the radiations. When the condenser 152 becomes fully charged to a predetermined potential, it discharges across a starting electrode and a main electrode of a glow relay tube 154, ionizing the gas within the tube and thus initiating a main discharge between the two main electrodes, which latter are impressed with a potential from a charged condenser 155. This main discharge causes periodic energization of a relay 156 from the source of supply or battery 153 each time the condenser 152 discharges.

The relay 156 is provided with a pair of contacts, one of which 15'! is connected to the source of supply L1 and the other of which is connected to the winding of the solenoid 148; and since the other end of the winding of the solenoid 148 is connected to the source of supply L2, the relay 156 periodically causes energization of the solenoid 148. There is accordingly a click of the dosage control at periodic intervals, the frequency of which depends on the intensity of the radiations from the lamps 9 or 11, and the dial 33 is rotated one notch on the ratchet gear, returning the dial from its initial setting of total ultra-violet units toward zero units.

Assuming now it is desired to administer a therapeutic treatment, or to subject a patient to a definite quantity of ultra-violet radiations, the dial 33 is depressed to release the clutch and rotated to agiven setting, such for example as 600 units, as shown in Fig. 2. The switches 35, 36, and 3'1 are then rotated in a clockwise direction which corresponds to the right as shown in Fig. 11. The right-hand signal lamps 38 will accordingly be illuminated, since the right-hand conductor bar 5'1 completes a circuit to the lamps from the conductors 124 and 125 constituting the source L1L2, thus indicating that the apparatus is set for dosage control.

It is to be noted, however, that the dosage control does not operate to complete a circuit to the transformers 1'1 and 41 and the time'control cannot be combined therewith, since the switches 35, 36, and 3'1 are common to both these controls. This accordingly leaves only the tapering and manual controls for combination with the dosage control.

Assuming, first, that the manual control is combined with the dosage control. by rotating the switches 2'1, 28, and 29 to the left, as shown in Fig. 2 and corresponding to the upward position in Fig. 11, then both transformers 1'1 and the transformer 4'! will be energized, as well as the upper signal lamps 38 illuminated to indicate operation of the manual control. After setting the manua control knob 23 to the desired intensity, the main line switch is closed, starting the apparatus into operation.

As before mentioned, the dosage control periodically operates and will continue to so operate until the cam 129 closes the respective contacts 138-132, 133-134, and 135-136, at which time the total units indicated on the dial 33 will have been administered. Again referring to Fig. 11, it will be noted that these contacts are electrically connected to the same energizing circuits for the respective relays 49, 59, and 52, as are the contacts 169-110, 112-! 13, and 114-1 15 of the time control, upon movement of the switches 35, 36, and 31 to the right, as shown in Fig. 11. Thus closure of the contacts 130-132, 133-134, and 135-136 will cause energization of the relays 49, 50, and 52, respectively, with attendant opening of their respective contacts and interruption of the energizing circuits for both transformers H and the transformer 4'5, in the same manner as previously described relative to the operation of the time control.

Up to the present time no standard unit of measurement has been adopted for ultra-violet radiation so that no definite term can be given to the graduations on the dosage control knob 33 other than ultra-violet unit. According to the invention, as shown and described in the above mentioned Patent No. 2,037,925 and as herein described, the discharging of the condenser upon its being charged by ultra-violet radiations impinging upon the photo-cell represents a definite quantity or unit of ultra violet radiations and thus each progressive step of the dosage control knob 33 from its preselected setting toward zero indicates a unit of ultraviolet radiations.

The intensity of the radiations may be taken as the rate of units per minute or clicks of the meter portion of the apparatus comprising the rotatable control knob 33. To employ the dosage control it is only necessary to consult the chart of Fig. 13 and set the control knob accordingly. For example, from Fig. 13 it will be noted that an exposure of say five impulses per minute for ten minutes has, roughly, the same destructive effect on the same micro-organism as ten impulses for five minutes, or a total, in either case, of fifty impulses. Thus by multiplying impulses or clicks per minute by time of exposure, the total number of impulses for any point on the chart of Fig. 13 can be readily obtained.

Assuming now an actual case, the chart of Fig. 13 shows that it is safe to expose uncovered viscera for a period of thirty minutes to an intensity of approximately seventeen and one-half impulses per minute, or a total of 525 impulses. Simply by setting the dosage control knob 33 to the indicia representing five hundred and twenty-five, then step by step, in individual impulses, the control knob will move from this presetting back to zero, at which point the ultraviolet lamps 9 and II are automatically extinguished in the manner previously described, thus positively limiting the total ultra-violet dosage received by the patient to a predetermined safe amount.

It is a known fact in the medical profession that long exposure of internal organs to air alone is harmful and frequently results in post-operative adhesions. Added to this is the traumatic effect of handling and, when ultra-violet radiations are used for preventing contamination of the incision, another factor is added to the hazard of long exposure of internal organs, all of which are cumulative in their effect.

To reduce this hazard, the tapering control may be combined with the dosage control simply by rotating the switches 21, 2B, and 29 to the right as shown in Fig. 2 and corresponding to the downward position of Fig. 11. When the main line switch (not shown) is closed, both the tapering control and the dosage control function in the manner previously described.

It is to be noted, however, that at the beginning the intensity of the radiations, regardless of the setting of the dosage control, is greatest, which means that the clicks of the dosage control will be more frequent in a given time period. As the tapering control continues to operate, the intensity of the ultra-violet radiations automatically tapers 01f from maximum intensity, during greatest air turbulence and contamination caused by the bustle preliminary to the actual operation, to decreased intensity when the occupants of the operating room have quieted down to the serious work of the actual operation and the need for intense radiations has decreased.

However, the tapering control portion of the apparatus reduces the intensity of the ultraviolet radiations apace with the normal settling of air-borne micro-organisms out of suspension. At the same time the dosage control portion of the apparatus continues to operate and when the total preselected dosage has been administered, the lamps 9 are extinguished in the same manner as though the dosage control was independently operating. It should also be noted that the tapering control in no way interferes with operation of the dosage control inasmuch as the intensity is greatest at the beginning of the operation, which thus applies more ultra-violet units to the patient in a given period of time. As the tapering control continues to operate, the time period merely increases in which a unit of ultra-violet is administered. Moreover, the speed of rotation of the tapering control is so proportioned that the total possible dosage can be administered prior to the tapering control interrupting the transformer energizing circuits and extinguishing the lamps 9 and II.

It thus becomes obvious to those skilled in the art that a method and apparatus is herein provided for subjecting a hospital operating room to ultra-violet radiations of-i'highly bactericidal and therapeutical wavelengths. Moreover, the patient is subjected directly to these radiations with all the occupants of the operating room surrounded by a barrage forming a wall of such radiations. This accordingly prevents eddy currents of air carrying micro-organisms, from contaminating the open incision or the hands and instruments of the surgeon and assistants.

The intensity of the generated radiations is initially set so that each ultra-violet unit will maintain a definite maximum intensity and yet a "manual control located at a centrally located control panel may be regulated to vary the intensity as desired over a range from the preset maximum to zero.

The apparatus of the present invention is also provided with an automatic tapering control which tapers ofi the intensity of the ultra-violet radiations, to oiTset the cumulative effect of air exposure. Moreover, the tapering control portion of the apparatus reduces the intensity of the ultra-violet radiations apace with the normal settling of air-borne micro-organisms out of suspension, from maximum intensity during greatest air turbulence and contamination, to decreased intensity when the need for intense radiation has decreased.

In addition, the present invention enables the generation of radiations of a selected intensity for definite periods of time by connecting the ultra-violet lamps to the time control, or when desired the apparatus is placed under the dosage control, thus limiting the amount of ultra-violet radiations to which the patient is subjected to a definite quantity and well within safe tolerance limits. Moreover, all of the lamps may be controlled by a combination of these con trols or, when desired, the ultra-violet unit to which the patient is subjected may be under one control, while the auxiliary units are subjected to a difierent type of control.

aecarez Although one embodiment of the present in-- vention has been shown and described, it is to be understood that other modifications may be made without departing from the spirit and scope of the appended claims.

I claim: a

1. An electrical apparatus particularly adaptable to hospital operating rooms comprising means for generating highly bactericidal ultraviolet radiations of preselected intensity and directly projecting said radiations toward a patient disposed upon an operating table to prevent contamination of an incision during a surgical operation by air-borne micro-organisms originating with the operating team, and a plurality of means spaced about the operating table for generating highly bactericidal ultra-violet radiations of preselected intensity and directly projecting said radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying micro-organisms from contacting the operating team and surgical instruments and the microorganisms being thereby transferred to the patient.

2. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above a patient on an operating table for directly irradiating the patient toprevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms thereby being transferred to the patient, means connected to the source supported by said central unit and operable to maintain a constant preselected maximum intensity of radiations from source throughout the useful life thereof, and means connected to the ultra-violet generators of said auxiliary units and operable to maintain a constant preselected maximum intensity of radiation therefrom throughout the useful life of said generators.

3. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminat ing micro-organisms from contacting the operating team and surgical instruments and the microorganisms being thereby transferred to the pa- .tient; and means carried by each auxiliary unit and operable to regulate the intensity of said pair of ultra-violet generators so as to maintain the 4. An electrical apparatus particularly adaptable to hospital operating rooms com rising ataminating of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and themicro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary units including switches manually operable to selectively connect said units to said control means to cause the latter to simultaneously vary the intensity of said source of ultra-violet of the central unit and the intensity of said ultraviolet generators of said auxiliary units.

5. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bac- Ytericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, means connected to said source of ultraviolet supported by said central unit and operable to maintain a constant preselected maximum intensity of radiations from said source throughout the useful life thereof, and means connected tothe ultra-violet generators of said auxiliary units and operable to maintain a constant preselected maximum intensity of radiations throughout the useful life thereof, and control means adapted to be electrically connected to said central unit and said auxiliary units including switches manually operable to selectively connect said units to said control means to cause the latter to simultaneously vary the intensity of said source of ultra-violet of the central unit and the intensity of said ultra-violet generators of said auxiliary units from zero to their preset maximum.

6. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in anuncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary units including switches operable to selectively connect said units to said control means and means for automatically operating said control means to cause the intensity of said source of ultra-violet of the central unit and the intensity of said ultra-violet generators of said auxiliary units as selected by said switches to gradually taper during a surgical operation.

'7. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, means electrically connected to said source and to said generators and operable to maintain a constant preselected maximum intensity from said source of ultra-violet supported by said central unit and from the ultra-violet generators of said auxiliary units throughout the useful lifethereof, and control means adapted to I be electrically connected to said central unit and said auxiliary units including switches operable to selectively connect said units to said control means and means for automatically operating said control means to simultaneously cause the intensity of said source of ultra-violet of the central unit and the intensity of said ultraviolet generators of' said auxiliary units as selected by said switches to gradually taper from the preselected maximum determined by said last-mentioned means to zero during a surgical operation.

8. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly ba'ctericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiationsv in the form of a bactericidal wall enclosing the operating team in an uncontaminated. zone to prevent air currents carrying con taminating micro-organisms from contacting the operating, team and surgical instruments, and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central, unit and said auxiliary units including switches selectively operable to connect said units to said control means and means for operating said control means to cause the intensity of the source of ultra-violet of said central unit to remain at a preselected intensity while causing the intensity of the ultra-violet generators of said auxiliary units to gradually taper from a preselected maximum to zero, or to cause the intensity of the ultra-violet generators of said auxiliary units to remain at a preselected intensity while causing the intensity of the source of ultra-violet of said central unit to gradually taper from a preselected maximum to zero, depending upon the selection of said switches.

9; An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-Violet generator of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary units including switches operable to selectively connect said units to said control means and timing means for automatically operating said control means to cause the emanation of ultra-violet radiations of a constant preselected intensity from the source of said central unit and the generators of said auxiliary units for a definite preselected period of time.

10. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal Wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary unit including switches operable to selectively connect said units to said control means and timing means for automatically operating said control means to simultaneously cause the ultra-violet radiations from the source of said central unit and the generators of said auxiliary units to gradually taper in intensity for a definite preselected period of time.

11. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operbactericidal radiations for directly projectingthe' radiations in the form of a bactericidal wall enclosing the operatingteam inanuncontam-y inated zone 150 prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary unit including switches selectively operable to connect said units to said control means and timing means for auto-= matically operating said control means to cause the emanation of ultra-violet radiations of a constant preselected intensity from the source of said central unit while causing the ultra-violet radiationsfrom the generators of said auxiliary units to gradually taper in intensity for a definite preselected period of time, or to cause the emanation of ultra-violet radiations of a gradually tapering inten'sityirom the source of said central unit while causing the ultra-violet radiations from the generators of said auxiliary units to remain at a preselected intensity for a definite preselected period of time.

12. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bacteri cidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary. units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall en-- closing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary units including switches operable to selectively connect said units to said control means and means for automatically operating said control means in response to a preselected total dosage of ultra-violet radiations being administered to a patient to cause a cessation of such radiations from the source of said central unit and the generators of said auxiliary units.

13. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central'unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the; patient, and control means adapted to be electrically connected to said central unit and said auxiliary unit including switches operable to selectively connect said units to said control means and means for automatically operating said control means in response to a preselected total dosage of ultra-violet radiations being administered to a patient to cause a cessation of such radiations from the source of said central unit or from the generators of said auxiliary units, depending uponthe selection of said switches. n

14. An electrical apparatus particularly'adaptable' to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosingthe operatingteam in an uncontaminated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electrically connected to said central unit and said auxiliary unit including switches operable to selectively connect said units to said control means and means for automatically operating said con,- trol means in response to a preselected total dosage of ultra-violet radiations being administered to a patient to cause a cessation of such radiations from the source of said central unit and the generators of said auxiliary units, and for automatically operating said control means to cause the intensity of the ultra-violet radiations to gradually taper while the patient is subjected thereto. 1

15. An electrical apparatus particularly adaptable to hospital operating rooms comprising a central unit supporting a source of highly bactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosingthe operating team in an uncontam inated zone to prevent air currents carrying contaminating micro-organisms from contacting the operating team and surgical instruments and the micro-organisms being thereby transferred to the patient, and control means adapted to be electricallv connected to said central unit and said auxiliary units including switches operable to selectively connect-said units to said control means and means for automatically operating said control means in response to a preselected to automatically taper while, causing the intensity of the ultraviolet radiations from said aux,- iliary units to remain constant, or operable, to cause the intensity of the radiations from said central unit to remain constant while causing the intensity of the radiations from said auxiliary units to automatically taper, simultaneously with the administration of a dosage to a patient.

16. An electrical apparatus particularly adaptable to hospital operating rooms comprising a. central unit supporting a source of highlybactericidal ultra-violet radiations and disposed above the patient on an operating table for directly irradiating the patient to prevent contamination of an incision during a surgical operation by micro-organisms originating with the operating team, a plurality of auxiliary units spaced about the operating table and. provided with a pair of ultra-violet generators of highly bactericidal radiations for directly projecting the radiations in the form of a bactericidal wall enclosing the operating team in an uncontaminated zone to prevent air currents carrying containinating' micro-organisms from contacting the operating team and surgical instruments and the, micro-organisms being thereby transferred to the patient, and a control. panel remotely disposed relative to said central unit and said auxiliary units, mechanism carried by said control panel and operable by a controlknob to preselect the intensity of the ultra-violet radiations from said central and auxiliary units during a surgical operation, mechanism carried by said control panel and operable by a control knob to cause the intensity of the radiations from said central and auxiliary units to gradually taper during a surgical operation, mechanism carried by said, control panel and operable by a control knob to preset the total time radiations are emitted from said central and auxiliary units during a surgical operation, mechanism carried by said control panel and operable by a control knob to preset the total dosage of radiations administered to a patient from said central and auxiliary units, and a plurality of switches carried by said control panel and selectively operable to electrically connect the source of said central unit and the generators of said auxiliary units separately or together to any one of said mechanisms and. operable to electrically connect the same separately or together to more than one of said mechanisms.

JOSEPH F. CQLLINS.

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