WO1988005665A1

WO1988005665A1 - A steam sterilizer

Info

Publication number: WO1988005665A1
Application number: PCT/AU1987/000023
Authority: WO
Inventors: Peter David Lawrence
Original assignee: Foxtech Pty. Ltd.
Priority date: 1987-01-28
Filing date: 1987-01-28
Publication date: 1988-08-11
Also published as: KR890700362A

Abstract

A steam sterilizer has an insulated cabinet (10, 55) containing an open-topped sterilizer chamber (39, 56). A loading opening (12, 57) in the upper part of the cabinet (10, 55) leads directly down into the sterilizer chamber (39, 56). A sterilizer chamber door (15, 59) is horizontally slidable in the cabinet (10, 55) between retracted position clear of the sterilizer chamber (39, 56) and advanced position directly over the open top of the sterilizer chamber (39, 56). The advanced door is sealed to the sterilizer chamber by inflation of a gasket (19) under the door (15) or by manual operation of eccentrics (79) to force the door (59) down onto the top of the sterilizer chamber (56). Steam is generated in a boiler (48) and introduced to the sterilizer chamber (11) or is generated within the sterilizer chamber (56).

Description

Title: "A STEAM STERILIZER"

BACKGROUND OF THE INVENTION ( 1 ) Field of the Invention

This invention relates to a steam sterilizer of the type used, for example, in the central sterile department of a hospital. Equipment of this type hitherto used has ordinarily had a cylindrical steriliz¬ ing chamber with a front opening, closed by a hinged or sliding door with locking and sealing means. Front-loading chambers of this type are difficult to load so that the available space is utilised to the best advantage, as some articles tend to fall out before the door can be closed. The loading and unloading of such sterilizers is also rather awkward and inconvenient for the user.

SUMMARY OF THE INVENTION The present invention has been devised with the general object of providing steam sterilizing equip¬ ment which is particularly convenient and safe to use and efficient in operation.

With the foregoing and other objects in view, the invention resides broadly in a steam sterilizer including a cabinet, an open-topped sterilizer chamber in the cabinet, a loading opening in the cabinet leading down into the sterilizer chamber, a sterilizer chamber door mounted in the cabinet for slidable substantially horizontal movement to retracted open position or advanced closed position over the sterilizer chamber, sealing means for sealing the closed door to the top of the sterilizer chamber, and means for generating steam under pressure in the closed chamber. Other features of the invention will become apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS In order that preferred embodiments of the invention may be readily understood and carried into practical effect, reference is now made to the accomp¬ anying drawings wherein:

FIG. 1 is a perspective view of a sterilizer according to the invention,

FIG. 2 is a diagrammatic sectional view of the sterilizer,

FIG. 3 is a sectional detail drawing, to larger scale, along line 3-3 in FIG. 2, FIG. 4 is a perspective view of a sterilizer according to an alternative embodiment of the invention, in open position, and partly broken-away.

FIG. 5 is a perspective view of the sterilizer shown in FIG. 4, in a closed position, FIG. 6 is a plan view of the sterilizing chamber door of the apparatus shown in FIGS. 4 and 5,

FIG. 7 is a sectional view along line 7-7 im FIG. 6, and

FIG. 8 is a sectional detail draining, to larger scale, alone line 8-8 in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to FIGS. 1, 2 and 3 of the drawings, an insulated cabinet 10 has a sterilizing chamber 11 mounted within its lower front part, the chamber being of open-topped box-like form. The upper front part of the cabinet is Inclined upwards to the rear and is formed with a large oblique opening 12 above the open top of the sterilizing chamber 11. A cabinet door 13 is hinged at 14 to the upper front part of the cabinet 10 and, when the sterilizer is not in use, hangs ^■ down to the top of the back x^all of the sterilizing chamber 11.

The open top of the sterilizing chamber 11 may be closed and sealed by a horizontally movable steriliz- er closure or door 15 moving on flanged wheels 16 which travel on a pair of angled-section rails 17 within the side of the cabinet 10 , the sides of the door being closely but slidably engaged under these rails. Corres¬ ponding wheels 16 at opposite sides of the sterilizer door are driven by reversible electric motors 18 to move the door to open or retracted position, as shown in FIG. 2, or to closed or advanced position directly over the sterilizing chamber 11. The door 15, when in fully closed position, is sealed to the periphery of the sterilizing chamber top by an inflatable gasket 19 under the door 15. This gasket consists of superimposed upper and lower sections of a resiliently deformable material sealed about their edge portions. A metal retaining plate 20 is held by screws 21 under the gasket, its edges inset from the gasket edges so that when air or steam is introduced from a pressure line 22 into the gasket, a rectangular part of the gasket outwardly of the retaining plate 20 is inflated to press doxnwardly, as indicated at 23, so as to seal the sterilizing ehamb- er about its rim. Any suitable control means for feed¬ ing air or steam under pressure to the gasket, and for relieving the pressure when the door is to be opened, are provided within a housing 24 on the door.

When the sterilizer chamber door is advanced to its closed position, a pusher plate 25 on its front moves the cabinet door 13 hingedly from its closed position as indicated in broken outline in FIG. 3-

Within the sides of the cabinet 10 are two lifting arms 26, each having a pivot pin 27 at its upper or rear end slidable in a horizontal slot 28. The lifting arms are rigidly interconnected at an intermed¬ iate position by a cross-member 29. A bracket 30 on this member carries a trunnion-mounted nut 31 for an oblique lead screw 3 which may be driven by a revers- ible electric motor 33 through a gearbox 34 so that the two lifting arms 26 are simultaneously raised or lowered.

The lifting arms 26 are shaped at their front ends to form lifting hooks 35 for engaging the end portions of a loading bar 36. From the end portions of the loading bar a pair of carrier hooks 37 depend, for releasable engagement with a pair of studs 38 within the ends of a box-like loading cartridge 39 for carrying articles to be sterilized within the sterilizer chamber 11.

Associated with the chamber 10 Is a loading gantry 40 freely movable on castor-mounted feet 41 and with a pair of horizontal carrier arms 42 terminating in lugs 43 for engaging the loading bar 36 and support- ing the loading cartridge 39 suspended therefrom by the carrier hooks 37- The articles to be sterilized may be easily loaded into the cartridge 39 in any convenient location, and readily transported by the mobile gantry 40 to the cabinet 10. The gantry feet 41 are guided into guide channels 44 in the base of the cabinet 10, the loading cartridge 39 thus being brought into align¬ ment directly over the sterilizer chamber 11. The lift¬ ing arms 26 are then raised by the motor 34 and lead screws 32 so that their lifting hooks 35 engage the loading bar 36 and lift it clear of the gantry lugs 43- The gantry is then withdrawn a short distance and the motor 3 is driven in reverse direction so that the lifting arms 26 lower the loading cartridge 39 into the sterilizer chamber 11. The motors 18 are then operated to advance the sterilizer door 15 to its closed position. On the leading end of the door 15 are a pair of bar catches 45 which engage the loading bar 36 and push it clear of the studs 38 of the loading cartridge. A pair of pins 46 radiating from the ends of the loading bar 36 coact with fixed rails 47 within the sides of the cabinet to cause the loading bar to be so rotated that its hooks 37 are swung up to clear the front of the sterilizer chamber 11. The cabinet door 13 is brought to fully closed position by the pusher plate 25. The sterilizer door 25, when brought to its fully advanced position, is sealed to the rim of the sterilizer cabinet, as before described, and the steam sterilizing operation is carried out. This involves the introduction to an electrically operated^' steam generator 48 of water from a water reservoir 49 by way of a valve 50, conducting the steam generated, to the chamber 11 by electric heating elements and exhausting air from the chamber by way of a steam trap 51. The embodiment of the invention shown in FIGS.

4 to 8 is a smaller table-top sterilizer, its cabinet 55 enclosing an open-topped box-like sterilizer chamber 56 accessible through a loading opening 57 in the front upper part of the cabinet. Any suitable loading cart- ridge (not shown) for articles to be sterilized may be lowered manually into the sterilizer chamber. The cabinet door 58, in this embodiment, is fixed to and movable with the sterilizer chamber door 59. The sterilizer door 59 is mounted on pairs of wheels 60 its sides, and carried by brackets 61, the wheels riding on rails 62 fixed within the sides of^" the cabinet 55. These rails incline downwardly to the rear at a small angle to horizontal, so that the door assembly, when free, will move gravitationally to its retracted or open position. It may be manually advanced to closed position by means of a handle 63 on the cabinet door 58, and when so closed the door assembly is automatically engaged and held by a catch (not shown) within the cabinet 55, this catch being releasable by application by pressure to a catch release at 64. The sterilizer door 59 includes a sturdy cast metal plate 65 fitted at its underside with a gasket 66 of resiliently compressible material. The plate 65 is suspended from a carrier frame 67 comprising a pair of yokes 68 to which the wheel mounting brackets 61 are fixed, extending across the ends of the plate and rigidly interconnected by a pair of parallel members 69. Suspension rods 70 extending up from the plate 65 are slidable through angle brackets 71 fixed on the carrier frame 67 and loaded by compression springs 72. When the door 59 is fully advanced, clearance adjustment screws 73 carried at front and back of both yokes 68 are brought closely under a bar 74 fixed across the front of the sterilizer chamber 56, and under an angle member 75 fixed across, and extending above, the rear of the sterilizer chamber, the gasket 66 then clearing the rim of this chamber.

To seal the sterilizer chamber, the plate 65 is depressed to bring the gasket 66 firmly onto- the chamber rim. This is done by depressing a locking bar 76 fixed between the front ends of a pair of locking levers 77 which at their rear ends are fixed to the ends of an eccentric shaft 78 disposed transversely above the plate 65, rotatable in bearings in the two yokes 68 and engaging a series of eccentrics 79 engaging the top central part of the plate.

The articles to be sterilized are placed in a loading cartridge which is manually loaded into the sterilizer chamber 56. The door assembly is then man- ually drawn forward to its closed position and automat¬ ically retained in this position by the catch device. The locking bar 76 is pressed down to seal the sterilizer cabinet, and the sterilizing operation is commenced. To ensure that the sterilizer chamber is not accidentally unsealed during the sterilizing operation, there is formed in the underside of the plate 65 a recess 80 (see FIG. 8) and, when the steam within the sterilizer chamber 56 is brought to a predetermined level, part of the gasket 66 is forced into.the recess 80 to lift a pin 81 which is slidable through the plate. The pin 81 lifts a lever 82 fulcrumed at one end on the plate so that at its other end it acts to prevent rotation of the eccentric shaft 78 by fouling a set screw 83 of a collar 84 fixed on the shaft.

In this embodiment, steam is generated in the sterilizer chamber 56 to the bottom of which water is fed from a reservoir 85 through a control valve 86 and heated by electric heating elements 87, air being exhausted through a steam trap 88.

When the sterilizing cycle has been completed and the reduction of steam pressure in the sterilizing chamber permits the locking bar 76 to be raised to un¬ seal the sterilizer chamber, the door assembly will remain held by the automatic catch device until, by pressure applied to the catch release 64, the door assembly is freed to move gravitationally to its open position. The loading cartridge with its contents of sterilized articles may then be safely lifted from the sterilizer.

Sterilizers according to the invention will be found to be very effective in achieving the objects for which they have been devised. It will, of course, be understood that the particular embodiments of the invention herein described and illustrated may be sub¬ ject to many modifications of constructional detail and design, which will be readily understood by persons skilled in the art, without departing from the ambit of the invention hereinafter claimed.

Claims

CLAIMS:

1. A steam sterilizer Including: a cabinet, an open-topped sterilizer chamber in the cabinet, a loading opening in the cabinet leading down into the sterilizer chamber, a sterilizer chamber door mounted in the cabinet for slidable substantially horizontal movement to retracted open position or advanced closed position, sealing means for sealing the advanced door to the top of the top of the sterilizer chamber, and means for generating steam under pressure in the closed chamber.

2. A steam sterilizer according to Claim 1 wherein the sealing means includes: a resilient gasket fixed under the door, and means for inflating those parts of the gasket above the top edge of the sterilizer chamber to bring them under pressure onto the said edge.

3. A steam sterilizer according to Claim 1 wherein: the door is suspended from a carrier frame movable on tracks within the cabinet, spring-loading means bias the door upwardly relative to the carrier frame, and the sealing means includes a gasket fixed under the door and cam-operated means for releasably depressing the door relative to the carrier frame to bring the gasket under pressure onto the top edge of the sterilizer chamber.

4. A steam sterilizer according to Claim 3 wherein: the door includes locking means, operated by and during a predetermined level of steam pressure within the chamber, for locking the cam-operated means against release.

5. A steam sterilizer according to any one of the preceding claims wherein: the door is manually movable from retracted to advanced position, a catch automatically engages and holds the door releasably in its advanced position, and the door is so mounted in the cabinet as to move gravitationally to its retracted position upon release of the catch.

6. A steam sterilizer according to any one of the preceding claims wherein: there is associated with the cabinet a mobile gantry for carrying a loading cartridge for articles to be sterilized, the gantry is made for interfitment with the cabinet, supporting the cartridge above the loading opening in the cabinet, the cabinet includes lifting arms, and actuating means are provided for raising the cartridge clear of the gantry and, upon retraction of the gantry, to lower the cartridge through the loading opening into the sterilizer chamber.

7. A steam sterilizer substantially as herein described with reference to FIGS. 1, 2 and 3 of the accompanying drawings.

8. A steam sterilizer substantially as herein described with reference to FIGS. 4, 5, 6,7 and 8 of the accompanying drawings.