Equipment for sanitization of medical waste

Abstract: Equipment for automatically sanitizing medical waste is mounted in a tightly closable housing (2) provided with charge nd disacharge openings (9, 10). The housing contains: a shredder (20) for comminuting the inserted raw waste and for conveying the shredded material to a mixing vessel (32) where it is diluted by water and throroughly mixed; a container (27) for storing tubes filled with several kinds of sanitizing material is configured to dispense the required number and kind of tubes into the shredder in accordance with the pH value of the mixture in the vessel signalled to a selective valve mechanism (39) by a sensor attached to the vessel; it further includes a pump (33) for recirculating liquid from the vessel to the shredder, and a pump (34) for draining fluid from the mixing vessel; a conveyor (25) for conveying the sanitized waste out of the vessel and out of the housing; electronic and control equiment is provided for operating the various components.

Description: The present invention concerns an equipment for disinfecting medical waste. In most hospitals medical waste is generally collected in a central place and then treated by incineration or by grinding and heating, in order to destroy germs, noxious material and bacteria such as parthenogenic viruses. These processes are not only costly, but generate unpleasant exhaust gases and contamination of the surroundings. The present invention relates to equipment of small dimensions suitable for installing it in every hospital department, laboratory or clinic for local disposal of medical waste which includes bandages, needles and syringes, testing vials and the like. It relates particularly to a method and equipment for automatically grinding, disinfecting and neutralizing both acid and basic medical waste, and for disposing it after treatment. Various kinds of equipment for disposal of medical waste have been designed and disclosed in patents, all using grinding and shredding of the waste material and adding a sufficient amount of disinfecting material designed to destroy germs and bacteria. The shredded material is then mixed with water which is subsequently drained and the moist waste is discharged and removed. The following patents disclose different methods for disposal of medical waste which, however, possess not all the features necessary for obtaining an absolutely safe mass suitable for pouring it into the domestic sewage system. US-A-5,064,124 (CHANG) discloses a system for grinding, sorting and sanitizing medical waste which is characterized by a device for sorting the waste into lighter and heavier fragments. It also includes a device for returning and discharging the sanitizing liquid. US-A-4,269,364 (MORICONI) is for a needle chopping apparatus designed for disposal of needles, syringes and the like rigid medical waste by shredding it into small particles. No mention is made for sanitizing the waste before final disposal. US-A-3,926,379 (DRYDEN) discloses a destruction apparatus including a hammer mill serving to destroy disposable items and a liquid disinfecting reservoir which supplies disinfectant to a pump which discharges it into the mill. From the mill the disinfectant descends into a collecting bag provided with apertures through which the disinfectant is returned to the reservoir. The waste disposal apparatus described in US-A-3,386,668 (SHEPHERD) relates particularly to the disposal of hypodermic syringes. It includes a comminutor, means for adding liquid to the material and a porous container for receiving the comminuted material and to allow passage of the liquid through the apertures for recirculation. DE-A-3829380 (ORTMAYER) describes a shradder for medical waste and a separator for separating solid from liquid waste. Conveying means are provided for filling liquid and solids into separate containers which are to be hermetically closed to prevent dust from escaping into the surroundings. WO-A-91/12889 (PEARSON) describes a process and apparatus for batch treatment of infectious waste material in a fluidized bed reactor utilizing gas oxidation, preferably ozone gas diluted in air. The process and apparatus provide for the disinfection of infectious waste in a rapid, cost efficient manner allowing for disposal of such infectious waste material in an environmentally acceptable manner. US-A- 5,217,688 (VON LERSNER) discloses a method for disposing of infectious personal care waste, as well as pathological waste and equipment which can be configured for large municipal type use employing continuous process techniques for indivual sites such as hospitals. The waste is treated in a rotatable pressure vessel and heated. After the heating process the disinfected waste is conveyed to a separator and discharged. None of the apparatus described are designed for conversion of medical waste into a neutral innoxious mass which can be disposed in any city dump without danger of contaminating the surroundings. The equipment for disinfecting medical waste of the present invention is described in claim 1. The present method of disposing medical waste includes the following steps to be automatically carried-out by the equipment of the present invention. inserting the waste and shredding it, conveying the shredded material by gravity into a mixing vessel and adding water, measuring the pH-value, adding a disinfecting material suitable for neutralizing the waste. conveying a tube of a disinfecting material to the shredder, grindinq it and conveying it by gravity into the mixing vessel, active disinfection of the waste, draining water and conveying the waste into the domestic sewage into an internal waste container to be emptied when full. The method may also include return of the disinfected liquid from the mixing vessel into the grinder or shredder for added cleaning. A preferred embodiment of the equipment for carrying the above method into effect is in the form of a closed housing including the following components: 1. an inlet opening closed by a cover, 2. a motor-driven grinder or shredder of conventional design, 3. a mixing vessel containing a motor-driven stirrer. 4. a motor-driven conveyor extending from the mixing vessel to the sewage system or to a waste container. 5. sensor means mounted in the mixing vessel for measuring the pH-value and electronically operated valve means for adding the correct buffer from buffer-storage containers. 6. a container for storing tubes or capsules filled with disinfecting material, provided with an automatically operated flap for dropping a tube or capsule into the grinder. 7. a pump for recirculating diluted waste from the mixing vessel into the grinder or shredder, 8. a pump for draining liquid from the mixing vessel, 9. Electronics for operating the equipment, 10. Switching and controlling means. As an alternative the mixing vessel may be in the shape of a rotating drum provided with means for tipping it after each complete operation for pouring the material into the sewage system. In order that the invention may be fully understood reference is made on the accompanying drawings wherein Figure 1 is an isometric view of a housing containing apparatus for disinfecting medical waste, Figure 2 is a section of the housing illustrated in Figure 1, showing a first embodiment of the disinfecting equipment including a conveyor fo removing treated waste from the mixing vessel into a domestic sewage system, Figure 3 is a section of the equipment illustrated in Figure 2, showing removal of the treated waste into an internal container, Figure 4 is a section of the equipment ilustrated in Figure 2, including a screw conveyor for removing treated waste from the mixing vessel into a domestic sewage system, Figure 5 is a section of equipment including a mixing chamber rotating about an inclined axis and designed for emptying by reversing its sense of rotation by means of suitably shaped blades, Figure 6 is a section of equipment provided with a mixing vessel rotating about a vertical axis and with tipping means, showing the vessel in working position, Figure 7 is a section of the equipment illustrated in Figure 6 showing the mixing vessel in tipped position, Figure 8 illustrates a device for releasing disinfector contained in tubes or capsules into a hopper above the shredder, The housing of the equipment of the present invention illustrated in Figure 1 comprises a front wall 1, two side walls 2, a rear wall 3, a bottom 4 (the two latter visible in Figures 2 and 4) and a forwardly sloping top panel 5. A cover 6 closes an opening in the front wall serving for removal of treated waste, and a cover 7 closes a service opening in a side wall. Another closed opening 8 in the side wall serves for insertion of disinfecting fluid, and a closed opening 9 in the top serves for insertion of tube-packed disinfecting material, while an opening 10 in the top serves for insertion of raw waste. Pipe connections 11 and 12 serve as water inlet and outlet respectively, and number 13 denotes a cable for electric power supply. A control panel 14 and a nonobligatory printer output 15 are shown in the frontal portion of the sloping top panel. The waste treating equipment illustrated in Figure 2 essentially includes a shredder 20 driven by an electric motor 21, a mixing vessel 22, a stirrer 23 driven by an electric motor 24 and a belt-conveyor 25, with its motor not visible in the drawing. The auxiliary equipment for neutralizing the waste comprise a pH-sensor 26, a twin vessel 27 containing disinfecting material and electronically controlled valve means 39 for conveying the required amount of material via piping 28 into vessel 22, in accordance with the basic or acid nature of the waste. The equipment for supplying neutralizing material into vessel 22 comprises a container 30 filled with suitable material enclosed in tubes or capsules of a plastic or other material which are conveyed into a hopper 31 above the shredder 20 through an electronically controlled flap 29. The tubes are filled into the container through opening 9 shown in Figure 1. Additional equipment includes a chute 32 connecting the grinder with the mixing vessel, a pump 33 for pumping partly neutralized liquid through pipe line 33 into hopper 31 for spraying it into the shredder and onto the walls of the hopper for thorough disinfection. It further includes a pump 34 for supplying water to the mixing vessel and for draining liquid out of the treated waste. The conveyor lifts the material out of the mixing vessel and discharges it through funnel 35 into the main sewage system. Figure 3 illustrates the equipment which is identical with that shown in Figure 2 with the difference that the conveyor lifts the treated waste into a container 36 which is, from time to time, lifted out of the housing through door 7 for transporting it to a central dump. Figure 4 illustrates equipment which includes disinfecting and neutralizing components identical with those shown in Figures 2 and 3 except for replacement of the belt conveyor by a screw conveyor 25' serving to lift the treated waste out of the mixing chamber and to convey it into a sewage system or an internal movable container, respectively. The conveyor is driven by an electric motor 33 adapted to rotate the conveyor in both directions, one for emptying the vessel and the other for additionally stirring the contents. Figure 5 is a section through the housing at right angles to the sections shown in the previously described drawings and illustrating the shredder, the supply means for neutralizing liquid from another angle. Since these are identical with those described with reference to the former figures, identical numerals are being used to denote identical components in both cases. The apparatus differs from the previously-described in the shape and operation of the mixing vessel 50 which is rotatably mounted on an obliquely directed support (not visible) and is driven by an electric motor 51 by means of a belt or gear . It can be rotated by the motor in two senses of rotation for the following purpose:- Mixing blades 52 are attached to the side wall of the mixing vessel for mixing the waste, when rotated in one direction, and for emptying the waste out of the vessel into a container 53 through a chute 54, when rotated in the other direction. A pump 33 communicates with the inside of the vessel through piping extending through the support of the vessel and serves for adding and draining water, as well as for drawing of neutralizing liquid and spreading it onto the hopper and the shredder. Still another embodiment of the mixing vessel and its operation are illustrated in Figures 6 and 7 which show only the lower portion of the equipment since the components in the upper portion are identical with those in the previously described figures. Herein the mixing vessel 60 together with its driving motor 61 are normally mounted in vertical position on a horizontal axle 62 at the end of a lever 63 which can be rotated about a right angle to tip the vessel and the driving motor into horizontal position for pouring the treated waste into a container 64. It can be seen that pH-sensor 26 is likewise turned about a right angle, while being cpnnected to electronic controls by flexible wiring. Neutralizing fluid is inserted from its reservoir direct into the shredderand buffering liquid is poured into the vessel through flexible piping (not shown) terminating above the vessel. A pump 33 serving for supplying and draining water by means of flexible piping 67 and piping extending through the support and the bearing of the vessel. The vessel is provided with stirring blades 65 attached to its side wall which also serve to empty the vessel. The waste is conveyed from the shredder into the vessel by way of a foldable hopper 66 which is to be raised (Fig. 7) when the equipment is lifted into horizontal position. Figure 8 illustrates, at an enlarged scale, the top of the housing including the means for supplying neutralizing material. The drawing shows the top cover 5 of the housing including the opening 10 for insertion of untreated waste in bags, and opening 9 for insertion of tubes or capsules 37 into a chute 30 from where they are emptied into shredder 20 by means of the openable flap 29. A vessel 27 contains two kinds of neutralizing liquid for neutralizing acid or basic waste respectively, which is conveyed into the mixing vessel through piping 28. An optional feature of the apparatus is a printer adapted to issue a printed message after each operation, to the effect that all steps of the treating method were carried out in correct order. It will be understood that the various apparatus illustrated and described in the foregoing represent examples of the many possibilities for carrying the method of disposing medical waste into effect. However, these apparatus have been designed for the present purpose with the object of occupying a minimum of space in a hospital department, a clinic or a laboratory, thus saving the task of carrying the waste to a far-away central disposal unit as is the use today.

Claims: Equipment for disinfecting medical waste, including, a closed housing (1,2,3) provided with closable openings for inserting medical waste (10) and removing treated waste (6) and with closable openings for inserting disinfecting material (9), an electrically driven shredder (20) connected by hopper means (31) to said openings for inserting medical waste, a mixing vessel (22) mounted underneath said shredder (20), having an open top and being provided with electrically moved means (23) for stirring shredded waste material, means for adding water to said shredded waste inside said mixing vessel, a container (27) for holding liquid disinfecting material for neutralizing basic waste, a container (27) for holding liquid disinfecting material for neutralizing acid waste, sensor means (26) inserted into said waste inside said mixing vessel adapted to measure the pH-value of the waste and to transmit corresponding signals to a processing unit, conveying means (28) for drawing a quantity of disinfecting liquid from one of said containers (27) in accordance with a signal received from said processing unit means for conveying a fixed predesignated quantity of said disinfecting material through said shredder (20) into said mixing vessel (22), pumping means for drawing diluted waste out of said mixing vessel and for conveying it into said shredder sand said hopper means, pumping means (33) for draining liquid out of said waste in said mixing vessel (22), means (25) for emptying said mixing vessel (22) and for conveying drained waste into a sewage main or into a separate container, electronic operating means, and manual control means. The equipment as defined in claim 1, wherein each portion of said disinfecting material is enclosed in a tube or a capsule (30) and wherein a plurality of tubes or capsules are enclosed in a chute (29), one above the other, and wherein the bottom end of said chute (29) terminates above said shredder (20) and is provided with a flap to be opened by solenoid means for dropping one tube or capsule (30) each into said shredder (20). The equipment as defined in claim 1, wherein said mixing vessel (22) is stationary and includes a motordriven stirrer (23) in its side wall, a pH-sensor (26) in its bottom portion and pipe connections to pumping means (33,34) in its bottom portion. The equipment as defined in claim 1, wherein the means for removing said treated waste out of said mixing vessel (22) is a screw conveyor (25') with its inlet end positioned in the bottom of said mixing vessel (22) and with its outlet end connected to a container (36) or a sewage main. The equipment as defined in claim 1, wherein the means for removing said treated waste out of said mixing vessel (22) is a belt conveyor (25) with its inlet end positioned in the bottom of said mixing vessel (22) and with its outlet end connected to a container (36) or a sewage main. The equipment as defined in claim 1, wherein said shredder (20) is mounted above said mixing vessel (22) and wherein a chute (32) extends from the bottom of said shredder (20) to the open top of said mixing vessel (22). The equipment as defined in claim 1, wherein means (15) are provided for issuing a printed message confirming the steps of the waste treating process.

Inventors: MOSENSON BENI, MOSENSON, BENI
Applicants: MOLEDET KFAR BNEI BRITH MOSHAV, MOSENSON BENI, MOLEDET, KFAR BNEI BRITH, MOSHAV SHITUFI HAKLAI LTD., MOSENSON, BENI
Application year: 1995
Main classification: B02C19
IPC codes: B09B3, A61L11