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Publication numberUS2015775 A
Publication typeGrant
Publication dateOct 1, 1935
Filing dateNov 7, 1934
Priority dateOct 5, 1933
Publication numberUS 2015775 A, US 2015775A, US-A-2015775, US2015775 A, US2015775A
InventorsAbraham Manfred
Original AssigneeAbraham Manfred
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrically heated sterilizing and cooling apparatus adapted to be used as an ice box
US 2015775 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Oct. 1, 1935. M, ABRAHAM 2,015,775

ELECTRICALLY HEATED STERILIZING AND COOLING APPARATUS ADAPTED To BE USED As AN ICE Box Filed NOV. 7, 1954 @If/507, //f/f/ fg. 3 la Patented Oct. 1, 1.935


In Germany October 5, 1933 6 Claims. (Cl. 219.-35)

This invention relates to a sterilizing apparatus in which the sterilization is effected by the action of heated air on the goods to be sterilized, for example medical and surgical instruments, bandages, rubber articles and other goods.

According to the invention the sterilization is carried out with the aid of a hermetically closable container provided with thermie external insulation and containing an electric heating element for supplying the necessary heat. As the sterilizing chamber is hermetically closed only the heated air enclosed therein acts on-the goods to be sterilized, which are placed in the chamber, the maximum temperature of the air being automatically regulated. A detrimental effect upon the goods to be sterilized can consequently not take place as in all other methods of sterilizing.

The limitation to a maximum internal tempera- I ture according to the invention can be attained in that the capacity of the electric heating element and its dimensioning is in a certain relation tothe heat accumulating capacity or to the heat conductivity and to the thickness of the layer of insulation employed, and any excess of heat is led on to the outer side through the insulation layer. If the apparatus is to be employed for different sterilizing temperatures, it is provided with an automatically operating thermo-regulator by which the current is switched off when a certain internal temperature is reached.

For the purpose of increasing the heating effect and its uniform distribution over the whole of the interior of the container, this container is preferably provided with a polished metal lining, which by reflection of the heat rays prevents any undesirable absorption of heat by the container wall, especially by its insulation.

The electric source of heat is advantageously iixed on the inner surface of oneor more side walls of the sterilizing chamber, preferably opposite the door. The heat raysare then directed towards the `coldest portion of the sterilizing chamber which is evidently near the door.

Both the sterilizing apparatus and also the source of heat may be foldably mounted in order that the source of heat may be employed in vertical or horizontal position. The device for actuating the same may be coupled-with another device Which during the folding over of the source of heat positively changes its electric resistance and consequently its heating e'iciency. The container is automatically adjusted to diierent working temperatures in each of its two positions of use.

Recesses may be provided in the sterilizing chamber for accommodating the electric heating element and receptacles for cooling media and the like. The apparatus, if cooling media, such as solldied carbon dioxide, are accommodated therein, can be used as an ice box, when the source of h eat is switched out.

In order to accelerate the cooling of the container walls after the heat treatment has been terminated, when it is desired to change over the "apparatus for cooling purposes, a cooling means,

such as a water coil fed from any suitable source, l0 is preferably built into the insulating layer.

It is important for the sterilization, that all possibility of oxidation is eliminated, for example in the case of metal articles to be sterilized. This is attained in a vperfect manner according to the l5 invention in that the oxygen of the imprisoned air is used up by the resistance wire of the electric source of heat. For this purpose the source of heat is so arranged that it acts directly on the air. The resistance wires are therefore situated in the 20 sterilizing chamber and only protected against damage and contact by a netting. The heating effect is also considerably increased by this arrangement of the resistance wires.

Hollow spaces or air spaces are preferably provided in the insulating layer for preventing any effect of the external temperature.

The sterilizingy apparatus is, according to the invention, tted with a separate temperature regulator by means of Which any alteration of the desired temperature is prevented in, the sterilizing chamber. This temperature regulator consists of an element expandingunder heat and which at a certain temperature acts on a valve or the like so that cold air can iloW into the chamber and 35 the excess of heat is discharged from the chamber. By inserting differently regulatable elements expanding under heat, it is possible to regulate to any desired maximum temperature.

The door of the apparatus is vprovided with 40 closing devices effecting hermetic closure.

The apparatus may also be employed as cooking apparatus besides for sterilization and cooling purposes.

Two embodiments of the invention are illus- 45 trated in the accompanying drawing, in which:-

Fig. 1 shows an apparatus in side elevation partly in section.

Fig. 2 is atop plan and part sectional view of Fig. 1.

Fig. 3 shows a modiiied form of construction in longitudinal section.

The outer casing l 'of the lapparatus encloses an insulating layer 2, the exposed surface of which is lined with metal foil 3. An electric heating coil 5 is accommodated in a recess I in the wall of the container and separated from the interior of the container by a wire netting l. Hinge plates 8 are slidably located between guide ribs I on the side wall and held in position by means of pins I0 engaging in slots 9 in the hinge plates 8. The container door i2 is carried on the other end of these hinge plates I by means of hinges Il. This door I2 also consists of an outer wall I, an insulating layer 2 and a polished metallic lining 3. r:'he door I2 is provided with packings i I3 hermetically fitting in the rebate Il on the edge of the open side of the container when the door is closed. Turn-buckles i5 are foldably mounted one on each side wall of the container and when the door is closed, they engage in corresponding forks I8 projecting laterally from the door. By tightening the wing nuts of the turnbuckles, the hinge plates I slide in their guides I and the door is tightly pressed into the rebate. The current leads, switches and the like and also the control thermometer I`I are of usual construction.

According to Fig. 3 air chambers 25 are provided directly in the insulating layer 2 or in the wall I or 3. The door i2 can be swung downwards about hinges Il. All the edges of the door are bevelled. When being closed, the door, which has packings i3 on its edges, hermetically fits in the rebate il provided with similar bevelled surfaces. A screw II projects from the rebate I4 and for locking the door engages a screw nut I9, the nut being actuated from the outer side of the door by means of a handle 2U rotatably mounted therein. One or several such closing devices I8, I9, 20 may be provided at one or several points of the apparatus.

For the continual automatic regulation of the desired temperature in the sterilizing chamber the following arrangement is provided according to the invention:-

A temperature regulator consisting of an element 2| expansible under heat is fitted either in any of the walls of the casing or, as shown in Fig. 3 in the door. This element is iltted in a guide 22 made of suitable material mounted in the door and xed at 2l on the side adjacent the interior of the sterilizing chamber. The air imprisoned in the sterilizing chamber can thus ilow directly against this inner end of the element 2l.

On the freeend of the element 2| a valve 24 is mounted which, when the element 2| expands,

opens slightly so that cold yair can flow into and.

the excess heat can be discharged from the chamber. The valve 24 again closes when the element 2i contracts. This procedure recurscontinually and maintains a constant maximum tempera ture in the sterilizing chamber independently oi the external temperature and without switching in and out of the electric heating.

The place at which the expansible element is tted and its construction may be chosen to suit the actual requirements.

'I'he door may be provided with a known contact device which interrupts the current supply when the door is opened.

I claim:-

1. A sterilizingand cooking apparatus comprising in combination an outer casing adapted to be set up selectively on one of two adjacent sides, a door on one end of said casing, an insulating layer on the inner side of the walls of said casing and said door, said layer having a recess opposite said door, a metal foil lining said insulating layer to 4form a heating chamber and having an aperture registering with the recess in said insulating layer, an electric heating coil in the recesses in said insulating layer so that the heat rays are always directed towards the coolest portion of said chamber, and a wire netting over the aperture in said metal foil lining separating said I electric heating coil from said heating chamber.

2. In a sterilizing and cooking apparatus as specified in claim l, hinges secured to one edge of the door and eac'n having a. slotted plate, pins on said casing one engaging in the slot of each of l said plates and adapted to hold said hinge plates in position on said casing, ribs on the outer side of said casing adapted to guide said hinge plates, forks on the outer side of said door projecting beyond two opposite edges thereof, and turnbuckles one on two opposite walls of said casing each turnbuckle adapted to engage one of said forks to pull said door tightly against said casing.

3. In a sterilizing and cooking apparatus as specified in claim 1, hinges secured to one edge 5 of the door and each having a slotted plate, pins on said casing one engaging in the slot of each of said plates and adapted to hold said hinge plates in position on said casing, ribs on the outer side of said casing adapted to guide said 1 hinge plates, forks on the outer side of said door projecting beyond two opposite edges thereof, turnbuckles one on two opposite walls of said casing each turnbuckle adapted to engage one of said forks to pull said door tightly against said 3 casing, a rebate formed on the walls of said casing adjacent said door, and packings on the inner side of said door adapted, when the door is closed, to engage vsaid rebate and form therewith a hermetic closure. 4

4. A sterilizing and cooking apparatus as specified in claim 1 in which the metal foil lining the inner side of the door is polished to split up and reflect the heat rays impinging thereon from the heating coil. 4

5. In a sterilizing and cooking apparatus as specified in claim 1, the walls of said casing bevelled at the end adjacent said door, and said door bevelled towards each edge to correspond with the bevelled portion of said casing walls, a re- 5 bate formed on the inner end of. the bevelled portion of said casing walls, packing on the inner wall of said door adapted to bear against said rebate when the door is closed, said door having a hole near one of its edges, a screw forwardly 5' projecting from the rebate on the wall opposite said hinges and adapted to extend through said hole when the door is closed, and a screw nut in said hole adapted to engage said screw to press said door tightly against said casing, and a han- 6i die on said nut adapted to rotate the same.

8. In a cooking and sterilizing apparatus as specified in claim l, a temperature regulator comprising'an element expansible under heat mounted in said door, a guide carrying said element 6 and fixed to the inner side thereof, and a valve on the outer end of said element adapted when the temperature in said chamber reaches a pre determined maximum to open under the influence of the expanding element to ventilate said cham- 7( ber.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3482930 *Mar 23, 1965Dec 9, 1969Muenchner Medizin MechanikSterilizing process and apparatus
US4935604 *Sep 29, 1988Jun 19, 1990Dentronix, Inc.Method and apparatus for hot air sterilization of medical instruments
U.S. Classification219/408, 165/64, 62/132, 62/326, 422/22, 422/307
International ClassificationF25D23/02
Cooperative ClassificationF25D23/02
European ClassificationF25D23/02