US2548691A - Sterilizer - Google Patents

Description

April l0, 195,1 A. vlscHER, JR 2,548,691

STERILIZER Filed Jan. 25, 1943 5 Sheets-Sheet l April 10, 1951 A. vlscHER, JR 2,548,691

STERILIZER Filed Jan. 25, 1943 5 Sheets-Sheet 2 April l0, 1951 A. vlscl-IER, .JR 2,548,691

sTERlLIZER Filed Jan. 25, 1943 5 sheets-sheet s N lo 5. 10Q n I l. zag 132 l Il IIIH

April 10, 1951 A. vlscHER, .JRV 2,543,691

STERILIZER Filed Jan. 25, 1943 5 sheets-sheet 4 pr 10, 1951 A. msm-IER, JR 295485691 STERILIZER Filed Jan. 25, 1945 5 Sheets-Sheet 5 The means for closing the opening 39 which I have provided is particularly simple and effective and can be readily operated by aperson with no special training. This closure means is so designed that it may be readily closed and sealed Vafter the articles to be sterilized have been placed 'on the shelves and this closure means may be as quickly unsealed and removed to permit removal of these articles after sterilization.

The door 32 is preferably made of stainless steel sheet 44, or other suitable resilient material supported in a ferrule 46 attached toa rod 48 supported in a sleeve 59. The sleeve 59 has a rectangular neck 52 loosely fitting in a rectangular opening 54 in a door supporting strap 56 pivoted at 58 to a side of the container 29. The strap 56 is made of such length that its free end 69 engages the opposite wall of the container when the door is in closed position, as shown in Fig. 2.

The sleeve 59 is held by its rectangular neck against rotation in the door supporting strap 56 and a key 62 fixed in the member 50 extends into a slot 63 in rod 48, whereby this rod is held against rotation but is permitted to slide axially in the member 59. The door sheet 44, when in released position, assumes a semi-cylindrical shape with the axis of the cylinder parallel to the door support 56 so that a vertical projection of the door is in the form of an ellipse with a major axis greater than the diameter of opening 3.9 and a, vertical minor axis less than that diameter. By swinging the door strap 56 about its pivot 58, the door can be moved through the opening 3D. The play between the neck 52 and opening 54 makes it possible to manipulate handle 64 on rod 48 in such manner as to move the door somewhat relative to its supporting strap 56 and thus facilitate movement of the door through opening 39. When the door is in the position shown in Fig` 4, it can be brought into engagement with the sealing ring 66 at the inner side of the opening 30 by pulling outward on the center of the door. I shall now describe more fully the manner and means by which this is accomplished.

Referring more particularly to Figs. 2, 4 and 5, it will be seen that the sleeve 59 has an inclined or cam shaped outer end 68 and that the handle 64 has a sleeve-like extension 18 provided with a complementary inclined surface 'I2 which engages the inclined surface 68. The handle and its sleeve are freely rotatable on rod 48 and are retained in place by a C spring 'I4 engaging in complementary grooves in the sleeve 'I9 and rod 48 adjacent the outer end of this rod. Rotation of handle 64 rotates sleeve 19 and causes it to shift from the position shown in Fig. 4 to that shown in Fig. 2 and this shift in position moves the rod 48 outwardly and brings the door 32 into sealing engagement with sealing ring 66.

When it is desired to open the door, the handle 64 is rotated through 180 to move its sleeve 19 from the position shown in Fig. 2 to that shown in Fig. 4 and thereafter the door can be Withdrawn by swinging this door and its supporting strap 56 about pivot 58. In carrying out this withdrawing operation, the movement of the door through opening 30 may be further facilitated by manipulating handle 64 to pivot the door somewhat in its supporting opening in the strap 56 So that the left hand end of the door, as viewed in Fig. 4, will pass to the right of the left hand wall of the door opening.

The base of the container 20 is adapted to be filled with water to approximately the height indicated in Fig. 1 and a-pair of electrical heating elements 76 and i8 (Figs. 1 and 12) are immersed therein. The heating elements 'I6 and 'i8 are connected to a three-pronged plug 89, secured in a wall of the container 20 and adapted to be connected by a three-wire conduit to the control mechanism located in a control box 82 containing the switch mechanism and timing means for energizing and deenergizing the heating elements 16 and 18.

One end of the box 82 is provided with a dial 84 graduated in minutes and having a stop pin 86. A control handle 88 normally has its long end 90 in contact with the stop pin 86. The control handle 88 is attached to one end of a shaft 92 extending lengthwise of the control box 62 and passing through a conventional spring motor drive and escapement mechanism indicated generally at 94 and hereinafter referred to as clockwork mechanism.

A pair of mercury switches 96 and 98 are mounted in spring clips |90 and |92, freely pivoted on the shaft 92 and control the circuits leading to the heating elements 16 and 18. The switch 96 is so positioned that its own weight tends to swing it about the shaft to cause it to assume the vertical closed position shown in Fig. l0 and this switch is moved to open position by an arm |94 which is aixed to shaft 92 in non-rotatable relationship thereto by screw |96. The arm |04 for certain positions ofthe shaft 92 engages a laterally projecting ringer |98 integral with switch supporting clip |99.

The switch 98 is moved to and from closed position by a U-shaped frame H0 having arms H2 and H4 resting beneath opposite ends of the mercury switch 98. As best shown in Fig. l0, the frame H9 is composed of members H6 and H8, lying on opposite sides of the shaft 92, a felt friction strip |29 being interposed between the shaft and members H6 and H8. Any desired irictional engagement between the frame H0 and the shaft 92 can be secured by rotation of screw |22 to increase or decrease the friction between this frame and the shaft. The screw |22 is threaded into the lower frame member I I0 and a spring |24 presses the upper frame member I8 toward the lower frame member H0 with varying degrees of pressure, depending upon the adjustment of the screw |22.

I have provided means for limiting the movement of the switch 98 with the shaft 92. This means comprises a U-shaped stop member |26 which is riveted or otherwise suitably secured to one wall of the box 82 and has inwardly projecting ends |28 and |30 alternately engaged by the adjacent portion of the switch supporting frame H9. The arms |28 and |39 are preferably spaced so that the time consumed by the clockwork mechanism in moving the frame H0 from engagement with the arm |39 into engagement with the arm |28 corresponds to the length of time required to bring the water in the container 20 to boiling temperature and raising the steam pressure for sterilizing to a predetermined pressure, e. g., 15 lbs. gauge, which represents a sterilization temperature of 250 F.

The clockwork mechanism 94 is provided with a bell i 32 which is rung by a hammer, not shown, when the -articles placed in the container 29 have been completely sterilized. In lieu of the bell |32, any other suitable visible or audible indicator could be used.

The electrical connections are indicatedf in the: diagrammatic view of Fig. 12. In this View, the wires |42 and |44 lead from the switch box'. 82 and` are connected with the house lighting system or other source of supply and in the actual device would take the form of a conventional, flexible, insulated, electric cord having a plug to be inserted in an ordinary wall socket. 'Ihe high resistance, low output heating elementv 'I6 is connected in series with its control switch 96in a circuit |46? which isv connected across the wires |421 and |44 and also connected across these wires in a, second parallel circuit |48 containing the low resistance, high output heatingV element 'I8' and its control switch 98 arranged in series.

While the control mechanism which I have just`l described makes it very unlikely' that any excessive steam pressure will ever be built up in thel container 20, I prefer to` provide appropriate safety means so that even. the most abusive use of my sterilizer can not produce an explosion. I. have, therefore, provided the upper wall of the. container 28 with a nipple |34 having an open iupper end which is closed during. sterili- Zation by a weight |36 resting thereon. This weight constitutes a safety valve and if the pressureA in the container 20 rises above normal, the weight |36 will lift sufficiently to relieve this. pressure and willv thereafter re-seal with the upper end of the nipple |34 to prevent further escape or the steam from the container 20.

A conventional pressure gauge 38 is illustrated as being attached to a side outlet in the nipple |34v toindicate at all times the pressure existing in the container 20. As a further safety measure, I have also provided the upper wall of the container with a blow out plug |48 of synthetic rubber or other suitable material and this plug will blow out before the pressure in the container reaches a sufliciently high value to destroy the container.

In order to condition my sterilizer for use, the Wires |42 and |44 are connected to a suitable sourceof electrical energy and the bottom of the container 20 is lled with water to approxi-Y mately the level shown in Fig. 1. The articles to be'sterilized are then placed upon the shelves 34,

36; and"v 38- and the door 32 is-swung into a positionshown in Fig. 4. Handle Ellis-rotated through 180 to pull the door into sealing engagement with sealing ring S6, as shown in Fig. 2.

In aA particular embodiment, the high output heating element-T6 had a capacityv of 1000-watts and the low output heating elementA |8 had a capacity of 250- watts. Two and one-half min-- utesl were required to bringthe water in the container 26 t'oboiling temperature and tok-create the desired steam pressure in this container. After this pressure had once been created, the 250fwatt heating element was adequate tornaintainthisv pressure andi after both heating ele\ mentshad been turnedk 01T-, the pressure inA thel containerv dropped to atmospheric pressure in about four minutes.

If the operator using this particular embodiment of my invention turnedV the control handle 881until the long end 90 pointedv at |5`, the shaft 92 would be rotated in aclockwise direction through 180 and this movement would correspondto-a sterilizing or operating period of ilf-v teen minutes. rlhe first part of this clockwiseV movement of the shaft 92 would close the' switch 98 and energize the-high output heating element 'I8' and when theshaft 92L and switch 98 had water in the container 20.

6 moved through an arc corresponding to 21/2I mine utes on the dial 84,l further clockwise movement of the switch 98 wou-ld be arrested by engagement of the left hand end of the switch supportingv form I0 with the stop nger |30.

When theshaft 92 .had been rotatedin a clockwise direction through a distance corresponding to four minutes on the dial 84, switch 96'-v` would close, thereby energizing the low output heater 16. Switch 96y would continue to move with the shaft 92 until the heavy end of this switch reached its-lowermost position, whereupon further movement of the switch 96 would cease and further movement ofthe sha-ft would merely cause separation of switch linger |508` and control arm |04. This clockwise rotation of the shaft 92 by the operator winds up theclo'ckwork mechanism 94:` and as soon as the operator releases the control handle 98, this clockwork mechanism starts to rotate shaft-92 and handle 88 in a counter-clockwise direction.

The energization of heating elements 'Hik and |8V raisesthe temperature of the water in the base of the container 20 until steam is given off and until the pressure of this steam reaches the desired maximum. In the particular heater selected for purposes of illustration only, this re-` quires 21/2 minutes andV takes place while the lshaft 92 is being moved counter-clockwise through an angle corresponding' to 21/2V minutes on the dial 84. This counterclockwise movement of the shaft moves switch 98 in a counterclockwise direction and the circuit through this switch is broken just before the switch supporting frame' |||J engages the stopv |28: Further movement of" the shaft 92 in a counterclockwise direction mere- 1y producesV slippage between this shaft and the felt 20 clamped in the frame |U-.`

After the. high output heatingelement 18 has been cut out, the low output heating element T5 continues to supply heat` to the water in container 20 and to maintain the desiredsteam pressure therein. The heating element '|61 isi designed to produce slightly more heat than is necessary f to maintain the desired' steam pressure and eX- cess steam escapes by slightly lifting the weight |36 which in normal oper-'ation maintains a con'- stant maximum pressure inA thei container 28. Thepressure existing in the container 20S is-i'ndicated at all timesiby the gauge |38.

As the shaft 92' continues'torotate -inf' aicounterclockwise directiomarm |04`engages'switch finger |08` and causes switch 96 to move with shaft-92. After the shaft has moved through an arc corresponding to 11` minutes on the dial 84; switch 96 opens and breaks'the circuit of the heating. element 16.

Thereafter, no further. heat issupplied tothe container drops to atmospheric pressure ineabout four minutes, at which time, the end. 98 of control handle 88 will have engagedV stop 86 and shaft 92 cornes to rest. Just as this occurs, the

bell |32 rings and gives an audible notice that upper end of the nipple |34, there is nodanger thatthis typev of safety valve willstick.v The onlycircumstances' under Which a'further safety The pressure in thecontrol would be useful, is where a heavy towel or other article is carelessly thrown or placed over the weight 136. Under these circumstances the plug 14D would blow out before the pressure in the container 26 could rise high enough to burst this container.

It will be understood by those skilled in the art that the particular values referred to in describing the operation of a particular embodiment of my invention were illustrative only and that the heating elements may be given any other values desired. The time required to raise the temperature in the container to operating temperature will, of course, vary with the output of the heating elements, the volume of water in the container, and various other factors. An important feature of my invention, however, resides in the arrangement whereby the maximum heating current is required only during the initial operation of the sterilizer and thereafter only a minimum heating current is required. Even this minimum current is out ofi an appreciable time before the sterilizing operation is completed, in order to utilize the heat stored up in the water and in the container itself. This feature materially increases the eiiiciency of operation and reduces the current consumption.

The embodiment of Figs. 13 and 14 differs from the previous embodiment and principally in the means for mounting the flexible door. In this embodiment, the container 2G1lis mounted in a pair of annular supporting members 262, of which only one is shown. It will be understood that these supporting members may be provided with suitable legs generally similar to those shown in the previous embodiment. The annular support shown in the drawing is provided with a pair of ears 204 to which a hinge 206 is pivotally connected by one leg of a U-shaped hinge pin 2138. The other leg of this hinge pin forms a pivotal connection between the hinge 266 and one end of a door supporting strap 216.

The flexible door 212 is substantially identical with the door 32 of the previous embodiment. This door has a central rectangular opening receiving the square section 214 of a mounting screw 216. The leaf spring 218 has a similar squared opening and is clamped between the door 212 and shoulder 229 of the mounting screw 216.

The door and spring are secured to the mounting screw by a nut 222 threadedly engaging an extension 224 of the mounting screw. A washer 226 is preferably interposed between. the nut 222 and the door 2 I 2 to make a steam-tight joint.

The mounting screw 216 is supported in a sleeve 228 rotatable in the cylindrical recess 266 formed in a boss 232 which constitutes an integral part of the door supporting strap 216. The sleeve 226 is provided with a threaded portion 234 which engages the main threaded portion of the door mounting screw 216. The anti-friction washer 236 may be interposed between an end oi the sleeve 228 and a flange 238 which limits inward movement of this sleeve.

The sleeve 228 is rotated by a knob or handle 2411 made of Bakelite or other suitable material and having a metal thimble 242 moulded therein. The thimble 242 has a cylindrical recess which freely receives the outward end of the mounting screw 216 so that this end of the mounting screw moves in and out of this cylindrical recess as the handle 246 and sleeve 228 are rotated. A screw 244 serves to attach the sleeve 228 to the tubular extension 2460i the knob 246, but

torque is transmitted from the knob to the sleeve through means described below.

The outward end of the mounting screw 216 has a tap recess into which is screwed a screw 248 having a head whose diameter is approximately the diameter of the apexes of the threads on the mounting screw. The head of screw 248 thus prevents sleeve 228 from being entirely removed from the mounting screw 216 in the normal operation of the mechanism.

In Fig. 13 the door is shown in full lines in the closed position. In this position the turned over edge 250 of the flexible door 212 is in sealing engagement with the sealing ring 252 carried by the container 200, and the free end 254 of the door supporting strap 210 is rmly engaged against the end of the container 2011. When it is desired to open the door, the knob 240 is rotated in a counterclockwise direction. This permits the mounting screw 216 to move inwardly under the inuence of spring 218 and as rotation of knob 246 continues, the flexible door 212 assumes a semi-cylindrical shape with the axis of the cylinder parallel to the door supporting strap 210. Rotation of the knob 2411 is limited by engagement of the threaded part 234 of the sleeve 228 with the head of screw 248 and when this occurs the door is in the completely collapsed position.

It is to be noted that the outer end of sleeve 228 is provided with notches 256 which receive ribs 258 of knob 246 and that these ribs serve to transmit to the sleeve 228 the rotative force exerted on the knob 240.

When the flexible door has been sufficiently collapsed, the knob 240 is moved to the right to cause the parts to assume the dotted line positions shown in Fig. 13. Thereafter the door can be swung out of the container by merely pulling on the knob 240. When it is desired again to seal the container, the door is swung back into the open end of the container. As the door enters the container, the knob 2411 is moved to the right to place the righthand part of door edge 250 behind the adjacent part of the sealing ring 252 and just before the free end 254 of the door supporting strap engages the end of the container, the knob 240 is moved to the left to centralize it relative to the container and to bring the lefthand portion of the door edge 250 behind the lefthand portion of the sealing ring 252.

Knob 240 is now rotated in a clockwise direction and this draws the mounting screw 216 and the central portion of the door outwardly, or downwardly, as viewed in Fig. 13. The door thereupon assumes a generally circular shape and the entire edge portion 256 contacts the sealing ring 252 and forms a fluid-tight seal therewith. Rotation of the door and mounting screw 216 is prevented by the leaf spring 218, which has a rectangular opening engaging the rectangular portion 214 of the mounting screw and which has ends 260 and 262 slidably engaged in longitudinal grooves 264 and 266 formed in the door supporting strap 2 10.

In the embodiment of Figs. 13 and 14, I have also shown a different arrangement for the pressure gage and pressure release valve. In this embodiment the pressure gage 268 is arranged in an inclined position so that it is more easily read. The pressure release valve is provided with a pivoted bail 21D which, in the position shown, overlies the weight 212 and prevents it from being blown off of its supporting nipple. The upper U end of the wire bail 210 may be swung to one side to permit removal of the weight 212 if desired. Except as hereinabove described, the ernbodiment of Figs. 13 and 14 may be identical with the previous embodiment and further description of the embodiment of Figs. 13 and 14 is, therefore, unnecessary.

It is to be understood that my invention is not limited to the details herein shown and described, but may assume numerous other forms and that my invention is to be construed as including all variations and modications falling within the scope of the appended claims.

I claim:

1. In a sterilizer of the class described, the combination of a container having an opening through which articles to be sterilized may be inserted and may subsequently be withdrawn, a sealing ring on the inside of said opening, a door formed of iiexible material andbiased toward a curved position permitting said door to be passed through said opening, a pivotal support having an elongated slot therein, a door supporting member engageable in said slot for supporting the door from said pivotal support, said member being shiftable longitudinally of the slot to facilitate manipulation of said door for passing the same through said opening, a handle, including cam means, for iiexing said door into sealing position, and means for creating steam pressure in said container to sterilize articles placed therein, said door in closed position serving to prevent escape of steam from said container and being sealed more tightly by increased pressure in said container.

2. In a device of the class described, the combination of a container having an opening therein and a sealing surface on the inside of said opening, a door of suitable size for making a fluid-tight seal with said sealing surface, said door being normally curled to a shape permitting it to pass through said opening, a support for said door hinged at one end to said container adjacent said opening, said support having a free end adapted to engage the edge of said opening diametrically opposite the hinged connection between said support and container, a handle for moving said door through said opening, and cam means carried by said handle for deforming said door into sealing engagement with said sealing surface.

3. Apparatus of the class described comprising a container having a cylindrical opening surrounded by an internal sealing surface, a door including a flexible plate normally curled to form a portion of the wall of a cylinder but capable of being deformed into a dish shape and when so deformed having a maximum diameter greater than the diameter of said opening, a support for said door, a hinge for said support, said hinge being located at one side of said container, the unhinged end of said support being adapted to engage the opposite wall of said container when said door is in sealing position, said support having a rectangular` opening therein, a member having a rectangular neck loosely tting in said opening, a door supporting rod slidable in said member, cam means for sliding said rod axially in said member, and a handle for actuating said cam means and for moving said door through' said opening.

4. Apparatus of the class described comprising a container having an opening, a door for sealing on the inner side of said opening, a supporting strap for said door, said door having a, dimension in the plane of said strap greater than the corresponding dirnension of said opening, a hinge, a pivotal connection between said hinge and strap, and a second pivotal connection between said hinge and container to permit lateral shifting of said door in the direction of said dimension.

5. Apparatus of the class described comprising a container having a circular opening, a door sealing on the inner side of said opening and flexing to permit said door to be moved through said opening, a mounting stud attached to said door, a supporting strap for said door, a hinge connecting said strap to said container, said strap having a cylindrical recess, asleeve rotatable in said recess and threadedly engaging said mounting screw, a handle for rotating said sleeve, a' spring confined between said door and strap and preventing rotation of said door and mounting screw relative to said strap, and means preventing separation of said sleeve and mounting screw.

6. Apparatus of the class described comprising a support, a supporting strap, a hinge connecting the strap to said support, a door mounted on said supporting strap and having a dimension in a direction parallel to said strap which is greater than the corresponding dimension of an opening through which said door is adapted to pass, and means for guiding the door for limited movement relative to the strap in a direction longitudinally of the strap.

ALFRED VISCHER, JR.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 643,949 Deane Feb. 20, 1900 1,180,895 Way et al Apr. 25, 1916 1,318,168 Newsom Oct. 7, 1919 1,348,837 Allen Aug. 10, 1920 1,352,289 Lelean Sept. 7, 1920 1,377,725 Pentz May 10, 1921 1,600,093 Capay Sept. 14, 1926 1,702,480 Newsom Feb. 19, 1929 1,934,826 Shepherd Nov. 14, 1933 2,013,172 Petrone Sept. 3, 1935 2,065,895 Jandat Dec. 29, 1936 2,282,011 Vischer May 5, 1942 2,295,298 Sharp Sept. 8, 1942 2,373,620 Vischer Apr. 10, 1945

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