US3881503A

US3881503A - Apparatus for washing and decontaminating articles

Info

Publication number: US3881503A
Application number: US378748A
Authority: US
Inventors: John Francis Fox; Bernard Frank Harber
Original assignee: Ethicon Inc
Current assignee: Ethicon Inc
Priority date: 1972-07-12
Filing date: 1973-07-12
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06
Also published as: BR7305187D0; DE2335232A1; IT989836B; GB1432368A; AR197344A1; CA956208A

Abstract

An apparatus for washing and decontaminating anesthetic and other hospital equipment comprises a bowl having elements for supporting the equipment without agitation during operation of the apparatus. The apparatus is equipped with a tank for storing decontaminating fluid for a predetermined period of time and conduits for transferring the fluid between the tank and the bowl during the decontamination cycles of the apparatus.

Description

D United States Patent 1 3,881,503

Fox et al. May 6, 1975 [54] ggggif i fi gig ygi gr sg FOREIGN PATENTS OR APPLICATIONS 1,168,035 10/1969 United Kingdom 134/170 [75] Inventors: John Francis Fox, Edinburgh,

Scotland; Bernard Frank Harber, Poole, England Primary ExaminerEdward L. Roberts [73] Assignee: Ethicon, Inc., Somerville, NJ. Attorney Agent or Flrm-john Slmkamch [22] Filed: July 12, 1973 [21] App]. No.: 378,748 [57] ABSTRACT [30] Foreign Applicatio Priority Data An apparatus for washing and decontaminating anes- July 12, 1972 United Kingdom 32609/72 thetic and other hospital equipment comprises a bowl having elements for supporting the equipment without [52] US. Cl 134/57 R; 134/95; 134/103; agitation during operation of the apparatus. The appa- 134/ 170; 134/171 ratus is equipped with a tank for storing decontami- [51] Int. Cl B08b 11/02 nating fluid for a predetermined period of time and [58] Field of Search 134/95, 99, 103, 166 R, conduits for transferring the fluid between the tank 134/ 170, 171, 57 R and the bowl during the decontamination cycles of the apparatus. [56] References Cited UNITED STATES PATENTS 5 Claims, 4 Drawing Figures 3,739,791 6/l973 Fry et al. 134/170 X /9 a a H llll FMEEHEE 51975 3,881,503

SHEET ESP 3 PATENTEUHAY "61915 SHEET 3 BF 3 ill APPARATUS FOR WASHING AND DECONTAMINATING ARTICLES The present invention relates to apparatus for washing and decontaminating articles. and in particular to apparatus for washing and decontaminating anesthetic equipment and other items of hospital equipment.

Anesthetic equipment is subject to direct contamination by contact with each patient upon whom it is used. and thus is likely to contain deposits of blood. mucus. vomit, etc. It has not been the general practice to decontaminate anesthetic equipment except at extended intervals, or after a known infected patient has been treated. Accordingly there is a real risk of crossinfection occurring.

Various methods of decontaminating and/or sterilizing anesthetic equipment have been used. Anesthetic equipment is mainly formed from plastic, rubber or rubber-like material, but such materials. if sterilized in an autoclave, are subject to rapid deterioration. Indeed some plastics are destroyed by autoclaving and cannot be decontaminated in this way. In view of the high cost of anesthetic equipment. it is not economically feasible to use autoclaving as a method of sterilization of such equipment, at least after each use thereof.

In British Patent Specification No. l,l68,035, there is disclosed apparatus for washing and decontaminating anesthetic equipment. The various articles of anesthetic equipment are arranged at pre-determined locations within the apparatus. and. during a washing and decontaminating cycle, hot water at about 180F is forced through the various articles to wash them. If de sired. a detergent may be included in the water. This washing step lasts for about 2 minutes, at the end of which time the water is drained from the machine for about half a minute. This is then followed by a rinsing cycle with cold water which lasts for 2 minutes and is followed by another half minute drain period. A disinfecting cycle then follows in which water is heated to l90F by means of a heater located in the apparatus, and this water is forced through the various articles for ID minutes. The heating is then cut off, the water evacuated, and the washing equipment may be removed from the apparatus.

The washing of the equipment with water at 190F (85C) effects a degree of decontamination but will not kill the more resistant acid fast vacilli such as tubercle.

A number of tuberculocidal agents are available, but most of these are alcohol-based which is disadvantageous since alcohol tends to attack the plastic, rubber or rubber'like material from which the anesthetic equipment is made. The alternative tuberculocidal agents are very slow in their action.

A main object of the present invention is to provide apparatus for washing and decontaminating anesthetic and other hospital equipment which will destroy all vegetative organisms including tubercle bacilli.

According to the present invention apparatus for washing and decontaminating articles comprises a bow] forreceiving said articles and means for washing said articles. characterized in that the apparatus includes a storage tank for a decontaminating fluid, means for bringing the decontaminating fluid into effective contact with said articles when located wihtin the bowl, and means for returning the decontaminating fluid from the bowl to the storage tank at the end ofa decontaminating cycle.

Preferably the bowl contains support means. which may be removable from the bowl, for supporting said articles without agitation during operation of the apparatus.

A particularly suitable decontaminating fluid is acti' vated glutaraldehyde solution which is tuberculocidal. Such a solution is commercially available and is described in British Patent Specification Nos. 992,813 and 992,814. However if activated glutaraldehyde solution is discarded after a single use thereof. the cost of decontamination is unreasonable. However, activated glutaraldehyde solution is self-sterilizing and has a relatively long effective life, so that a given supply will remain effective for many decontaminating cycles.

By the use of the apparatus in accordance with the present invention, the activated glutaraldehyde solution is recirculated therethrough, and anesthetic equip ment and other items of hospital equipment can be decontaminated after each use thereof in a relatively cheap and quick manner. and without damage thereto.

Because activated glutaraldehyde solution does not have an unlimited practical life. the apparatus of the present invention preferably includes means for automatically evacuating the solution from the apparatus before the end of its practical life.

A preferred apparatus for washing and decontaminating anesthetic equipment in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. I is a view in perspective of the apparatus:

FIG. 2 is a diagrammatic representation of some of the more important working parts of the apparatus;

FIG. 3 is a view in perspective of the bowl and pipe frame of the apparatus; and

FIG. 4 is a block diagram showing the general arrangement of the control circuitry of the apparatus.

Referring to the drawings, portions of the apparatus are similar to that shown in the drawings of British Patent Specification No. 1.168.035, and comprises a cabinet 1 in which is mounted a bowl 2, preferably of stainless steel. The cabinet 1 is provided with a lid 3 for the bowl 2. Located within the bowl 2 is an impeller 4 which is driven by an electric motor 5. Also driven by the motor 5 is a centrifugal-type pump 6. The outlet of the pump 6 feeds two conduits 7 and 8 respectively. The conduit 7 is connected by a spigot arrangement 9 to a pipe frame 10, removable by means of the spigot arrangement 9, from the bowl. The pipe frame 10 includes pipes 11 which are each curved at their upper end so that pairs of opposed pipes 11 have outlet orifices which face and are aligned with each other (see FIG. 3).

In use, items of anesthetic equipment to be washed and decontaminated are placed in the bowl 2 and retained in position therein. They are not agitated during the washing and decontaminating cycle. Flexible corrugated rubber hoses are placed over opposed pairs of pipes 11. Re-breathing bags are placed over vertical tubes I2. Face masks are put onto spigots 13 on the lower half of the rack 14 which is suspended on the side of the bowl 2. Airways are pushed through elongated oval slots (not shown) in the rack with their flanges uppermost and are gripped by rubber inserts within the slots. Endotracheal tubes are pushed onto tapered nozzles 15 provided on the manifold of the pipe frame 10. The tapered nozzles I5 are of various sizes so as to enable large, medium and small tubes to be accommodated. Laryngoscope blades and sundry connectors and other small components are placed in a stretcher" type basket 16 which is suspended across the pipe frame 10.

The apparatus is provided with a programmed. timecontrolled system, which is operated by a mechanical key slidable within a slot. for automatically controlling the desired washing and decontaminating sequence. When the apparatus has been loaded with the equipment to be decontaminated, the lid 3 is closed, the program key is then depressed and the washing and decontaminating sequence starts. A solenoid operated inlet valve 17 opens to allow cold water from the mains to enter the bowl 2 through a break tank 18. Before the water enters the break tank, it passes through a detergent dispenser 19 which is mounted on a cover on the break tank 18. The detergent dispenser 19 is provided with a solenoid which can be energized to seal an air hole in the dispenser body. Inlet water passes through a venturi in the dispenser body and sucks detergent through a spigot only when the dispenser solenoid is energized shutting off the air hole.

A non-foaming detergent is stored in a plastic bottle mounted at the rear of the apparatus and is fed to the dispenser by small bore clear plastic tubing, the amount being metered by an adjustable screw set in the spigot in the dispenser body. Turning the screw anti-clockwise increases the amount of detergent used.

When the water in the bowl 2 is at the correct level, as determined by a probe 20, the inlet valve 17 is closed. The motor is energized and drives the impeller 4 and pump 6. Water is thus supplied to the conduit 7 and flows to the pipes 11 of the pipe frame creating a series of high velocity jets of water in and around the anesthetic equipment arranged in the bowl 2. The impeller 4 sprays water within the bowl 2 so as to wash the exterior of the equipment. This washing cycle lasts for 4 to 6 minutes. At the end of the cycle a two-way valve 21, which until this time has been closed, is actuated to a first open position allowing the water to be pumped to waste. After half a minute this two-way valve 21 closes.

The drain period is followed by a 4 minute rinse period with fresh cold water which is then pumped to waste for half a minute. A further 2 minutes rinse with fresh cold water and a further half a minute drain period when follows.

By this time, the equipment in the bowl has been thoroughly washed of solid contaminants and remains to be decontaminated. This decontamination step is effected using activated aqueous glutaraldehyde solution as described above.

A pump unit 22 is actuated to transfer a portion of the activated aqueous glutaraldehyde solution from a storage tank 23 to the bowl 2 via break tank 18. When there is sufficient solution in the bowl 2, as determined by the probe 20, the pump unit 22 is stopped. The solution is then pumped around and through the equipment by pump 6 and is sprayed over the equipment by the impeller 4. After 14 minutes. the decontaminating cycle ends, and the two-way valve 21 is actuated to a second open position for 2 minutes allowing all the glutaraldehyde solution to be pumped by pump 6 through conduit 8 and valve 21, back to the storage tank 23 for further use.

This is followed by a 2 minute rinse with cold water from the mains which is then discharged to waste for half a minute. Then follows another 2 minute rinse with cold water which is then discharged to waste for half a minute and this is finally followed by a 10 minute rinse with water. In this final step cold water is fed to the bowl 2 and a heater 24 is switched on to raise the water temperature to about C. A close limit thermostat triggers off an electrical sequence which switches off the heater, causes the hot water to be pumped to waste for 30 seconds and then actuates a solenoid 25 which raises the lid 3 of the bowl 2 by about 2 inches, so allowing residual water vapor to escape from the bowl without condensing onto the equipment, and allowing the equipment substantially to dry. The anesthetic equipment in the bowl 2 is removed and is patientready.

The interior of the stainless steel bowl 2 is so shaped, particularly by sloping all surfaces, that maximum drainage is obtained. The surfaces may be rendered self draining by coating them with an inert water-repellent material, thereby minimizing any dilution of the activated aqueous glutaraldehyde solution by the rinsing water previously in the bowl, and also assisting in returning substantially all of the solution to the storage tank 23 after a decontaminating cycle. The small amount of vibration from the impeller 4 further assists in draining the bowl.

Aqueous activated glutaraldehyde solution does not have an unlimited life in use, and in this connection. a 14-day timer, preferably operated by rechargeable batteries, is included in the apparatus so that after 2 weeks, the electronic circuits are actuated automatically to evacuate the aqueous activated glutaraldehyde solution to waste by a pump 22, bowl 2 and drain. There is thus no possibility of its reuse beyond its normal effective working life.

The pump unit 22 consists of two fractional horsepower centrifugal pumps one mounted horizontally and the other one mounted vertically on a mounting bracket. The function of the vertically mounted pump is to transfer glutaraldehyde solution from the storage tank 23 to the bowl 2 during the normal cycle of the apparatus and to pump the majority of the glutaraldehyde solution to waste via the bowl 2 during the glutaraldehyde evacuation cycle (at the end of the 14 day period). The horizontally mounted pump remains constantly primed with a small quantity of used glutaraldehyde solution which is retained in the reservoir after every glutaraldehyde evacuation cycle. The reservoir is connected to the glutaraldehyde storage tank 23 by a small bore plastic tube connected to a spigot situated at the lowest point in the tank 23, the purpose of the pump being to remove as much of the exhausted glutaraldehyde solution as possible and prevent contamination of the next tankfull of fresh glutaraldehyde solution.

The evacuation of the glutaraldehyde solution is effected by switching on the pumps 22 and 6, and actuating the two-way valve 21 to its first open position. The apparatus will then not operate again until a fresh batch of aqueous activated glutaraldehyde solution has been loaded into the storage tank and the 14 day timer has been re-set. if desired a sensor may be provided in the tank 23 so that the timer is automatically re-set at zero by the introduction of a fresh batch of glutaraldehyde solution.

Also associated with the 14 day timer is a warning light 26 which is automatically switched on after 13 days, so as to remind the operator of the apparatus to replace the batch of solution by the next day at the latest. At 14 days another light 27 is automatically illuminated to indicate the end of the effective life of the batch of glutaraldehyde solution. After 14 days. the timer an-programs" the key and effectively reprograms the control system to insure evacuation of the solution, i.e., the timer effectively over-rides the control system so that when the key is next depressed in the slot the solution is evacuated by activating the appropriate pumps and valves.

A lever sensor is included in the tank 23 so that if there is insufficient aqueous activated glutaraldehyde solution in the tank to effect decontamination of a batch of equipment, the apparatus will not operate until sufficient solution has been added to the tank to bring the supply back to its proper level.

In order to provide a safeguard, the lid 3 is locked when the apparatus is in use and raised only after bowl 2 has been evacuated. An emergency stop and lid-lift button is provided to stop operation of the apparatus in mid-cycle should this be necessary. The control system is thereby actuated to return any solution in the bowl 2 to the storage tank 23 or to discharge any water in the bowl 2 to waste. When the apparatus is restarted after such a stoppage, it commences operating from the beginning of the cycle thus insuring that all of the items of anesthetic equipment in the apparatus, including any newly introduced items, are subjected to a full washing and decontaminating cycle.

The general arrangement of the program control circuitry is illustrated in FIG. 4 by means of an electronic block diagram. The actual circuitry is similar to that employed in known automatic washing machines except that it is based on the washing/decontamination cycle described above wherein provision is made for the automatic evacuation of spent glutaraldehyde from the apparatus every 14 days.

Referring to FIG. 4, the main logic control circuit which provides the program for the washing/decontaminating cycle is illustrated at 29 and consists of three printed circuit boards constructed from the Mullard NORBIT TWO trademark, Hoover Limited, Perivale Greenford, Middlesex England range and adapted for the particular washing/decontaminating cycle described above.

The logic control circuit 29 is provided with information relating to the state of the various parts of the apparatus during operation through inputs 30. These inputs may be obtained, for example, from a glutaraldehyde storage tank depth probe, glutaraldehyde drain pump probe. push start and push stop bottons, lid switch, bowl depth probe and maximum washing temperature thermostat. The inputs 30 are fed to circuit 29 by means of input switch filters 31 which are designed to remove any microswitch *bounce", noise or electrical interference.

The logic control circuit 29 provides output relays 32 with the information necessary to perform the washingldecontamination cycle described above. The relay outputs 33 are connected to the various pumps, heaters, and valves etc., which are operative during the washing/decontaminating cycle.

A program timer 34 provides the necessary information to enable the logic control circuit 29 to provide the correct output information. The program timer 34 is, itself. a series of microswitches controlled by the above-mentioned mechanical key. Such a feature is well known on automatic washing machines.

The operation of the electronic circuitry is also controlled by a 14 day timer 35, the purpose of which has been explained above. A signal is passed from the timer 35 every 14 days to cause the logic control circuit 29 to signal the outputs 33 to evacuate the spent glutaraldehyde from the apparatus. This latter operation then occurs automatically the first time the apparatus is actuated at the expiration of 14 days from the provision of a fresh batch of glutaraldehyde solution, and makes it necessary for the operator to provide the apparatus with fresh glutaraldehyde solution before a new washing cycle can commence. The 14 day timer 35 is driven by means of a rechargeable battery so that even if the apparatus is disconnected from a source of mains electricity a signal is sent to the logic circuit 29 every 14 days to evacuate the glutaraldehyde solution.

What is claimed is:

1. In an apparatus for washing and decontaminating articles including a bowl having a motor driven impeller located therein and a top cover for sealing said bowl. a motor driven pump for supplying pressurized fluid to a support means having pipes connected thereto located within said bowl, each of said pipes having at least one outlet orifice and being adapted to have some articles connected thereto in a manner such that in use fluid from said pipes passes through the interior of the articles and into said bowl, said bowl having passage means connecting the interior of the bowl with the inlet of said pump and having a valve controlled drain, a heating coil located within said bowl, a storage tank for a decontaminating fluid, said fluid having a fixed effective life, means for bringing the decontaminating fluid into effective contact with said articles located within said bowl, means for returning the decontaminating fluid from said bowl to said storage tank at the end of a decontaminating cycle, and electrical control means for affecting the operation of said motor driven impeller, said motor driven pump, said bowl drain valve, said decontaminating fluid bringing means and said decontaminating fluid returning means; the improvement comprising:

means associated with said bowl for promoting selfdraining of bowl surfaces when a fluid is drained from the bowl; and

means associated with said electrical control means for regulating the operational life of said decontaminating fluid.

2. The apparatus of claim 1 wherein all of the interior surfaces of said bowl are sloping.

3. The apparatus of claim 2 wherein said draining promoting means includes a coating of inert waterrepellent material and wherein said regulating means includes a l4-day timer.

4. The apparatus of claim 3 also including means for regulating within close tolerance the upper temperature within the bowl.

5. The apparatus of claim 4 wherein said temperature regulating means includes:

a close limit thermostat located within said bowl, said thermostat being connected to said electrical control means to switch off said heater coil and operate said drain valve; and

an electrical solenoid, said solenoid being mounted to said bowl and being positioned to raise said bowl lid about 2 inches when activated, said solenoid being electrically connected to said thermostat through said electrical control means.

Claims

1. In an apparatus for washing and decontaminating articles including a bowl having a motor driven impeller located therein and a top cover for sealing said bowl, a motor driven pump for supplying pressurized fluid to a support means having pipes connected thereto located within said bowl, each of said pipes having at least one outlet orifice and being adapted to have some articles connected thereto in a manner such that in use fluid from said pipes passes through the interior of the articles and into said bowl, said bowl having passage means connecting the interior of the bowl with the inlet of said pump and having a valve controlled drain, a heating coil located within said bowl, a storage tank for a decontaminating fluid, sAid fluid having a fixed effective life, means for bringing the decontaminating fluid into effective contact with said articles located within said bowl, means for returning the decontaminating fluid from said bowl to said storage tank at the end of a decontaminating cycle, and electrical control means for affecting the operation of said motor driven impeller, said motor driven pump, said bowl drain valve, said decontaminating fluid bringing means and said decontaminating fluid returning means; the improvement comprising: means associated with said bowl for promoting self-draining of bowl surfaces when a fluid is drained from the bowl; and means associated with said electrical control means for regulating the operational life of said decontaminating fluid.

3. The apparatus of claim 2 wherein said draining promoting means includes a coating of inert water-repellent material and wherein said regulating means includes a 14-day timer.

5. The apparatus of claim 4 wherein said temperature regulating means includes: a close limit thermostat located within said bowl, said thermostat being connected to said electrical control means to switch off said heater coil and operate said drain valve; and an electrical solenoid, said solenoid being mounted to said bowl and being positioned to raise said bowl lid about 2 inches when activated, said solenoid being electrically connected to said thermostat through said electrical control means.