IT202100009308A1 - "AUTOMATIC PLANT FOR THE STERILIZATION OF HEALTHCARE WASTE WITH INFECTIVE RISK HIGH EFFICIENCY" - Google Patents

Description

Description of the patent application for an industrial invention entitled:

?High efficiency automated system for the sterilization of infectious risk medical waste?

The object of the present patent for an industrial invention relates to an automated plant for the treatment of dangerous and infectious risk medical waste, capable of working under very harsh operating conditions, such as to obtain very high levels of sterilization and to dispose of the finely shredded waste, in the suitable form to be reused as fuel for energy production plants.

The current Italian legislation D.P.R. 254/2003, which regulates hazardous medical waste, provides that the latter must be disposed of either by incineration, or by a sterilization process, observing strict operating parameters aimed at guaranteeing the inactivation of the microorganisms contained in this type of special waste.

The sterilization process to be applied for the reduction of the microbial load of dangerous sanitary waste must reach a level of S.A.L. (Sterility Assurance Level) not lower than 10-6, (probability of 1 in 1,000,000 of finding a non-sterile unit) and furthermore, according to the UNI 10384/94 regulations, the applied process must necessarily include shredding and drying, in order to reduce the weight and volume of the treated waste.

To obtain a level of S.A.L. not lower than 10-6, sterilization facilities must process hazardous medical waste at a minimum temperature of 135? and at a pressure of 4 Bar for a time of no less than 200 seconds.

The biggest difficulty? faced by sterilization plants that process medical waste, ? due to the great inhomogeneity? of said waste, being made up of sharp metal elements, such as needles, blades and syringes, from infected elastomeric materials such as gloves, catheters, cannulas and drips as well as from textile materials such as gauze and bandages, to other types of waste, including of an organic nature.

As always foreseen by the D.P.R. 254/2003, hazardous medical waste with an infectious risk must be placed in a double container, generally the internal one consisting of a nylon bag and the external one, of the rigid type, consisting of a cardboard or a reusable plastic container.

In particular, sharp metal waste must be placed inside specific plastic containers before being transferred together with the other types of waste, inside smaller containers. whether they are reusable or disposable.

According to another method of disposing of hazardous medical waste, without a sterilization system, both the reusable and disposable containers are collected by qualified personnel, to be transported to appropriate centers to undergo thermo-chemical treatments, subjecting, to the risk of infection, the entire chain of subjects employed for the transport of such waste, from their collection to their transfer to authorized centres, it being understood that ?????????? ???????????????????????????????????????????????? ??? ?

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this type of treatment contributes to increasing the economic costs of disposal and does not allow for the treatment of large quantities? of refusal.

A further difficulty? faced by the plants for the treatment of hazardous medical waste installed in hospitals and non-hospitals, ? that of having to guarantee, during the process, the absence of harmful emissions that would pollute the air in the environments adjacent to the plant, already subject? by their nature to particular restrictive standards.

Purpose of the present invention ? that of supplying a sterilization plant which carries out a very thorough reduction of the microbial load of the waste, an objective achieved through the use of specific conditions of temperature of 165?C, pressure of 6 Bar and duration of application of the saturated steam with which the waste is treated.

? a further object of the invention is to provide a treated waste at the outlet in a very fine and compact size, thanks to the use of a four-shaft shredder which allows to guarantee a very marked reduction in volume of the waste, and never below the 80% of the pre-treatment volume.

? Another object of the invention is to provide a system which guarantees in the environment in which installed, excellent health conditions? for the surrounding staff, drastically reducing emissions, thanks to the fact of keeping the waste loading hopper under vacuum and using a sequence of different and highly efficient filters.

? an advantage of the invention is that of providing a quality waste output, sterile and finely shredded, as a fuel which has a high calorific value, suitable for feeding energy production plants which exploit waste.

These and further purposes are achieved by the highly efficient automated system for the sterilization of infectious risk medical waste of the present industrial patent, described in a preferred non-limiting embodiment of further developments within the scope of the patent, with the help of the tables attached drawings illustrating the following figures:

Fig. 1, an isometric view of the plant;

Fig. 2, a front view of the plant;

Fig. 3, a functional block diagram of the sterilization cycle.

The treatment performed by the highly efficient automated system for the sterilization of infectious risk medical waste, hereinafter referred to for simplicity's sake as plant 1 it is divided into three parts, a first cycle, called preparation, a second sterilization cycle and finally a last cycle, called disposal.

In the preparation cycle, the infected waste? loaded inside a box 2 which rests on a load scale platform 3, located at the base of the structure of an automatic tilter 4, this latter, following the weighing data collected by the load scale platform 3, lifts the box 2 and overturn the contents inside a hopper 5.

Once the step of loading the waste into the hopper 5, equipped with presence-absence sensors and filling sensors, is concluded, and following its hermetic closure, the same is internally depressurized in order to aspirate the harmful emissions emitted by the waste.

The emissive components sucked into the hopper 5 are, by means of a pressing machine, conveyed to a filter unit 6, composed

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by a pre-filter, an H-14 efficiency HEPA filter and an activated carbon filter, of the rigid pocket type.

The filter unit 6 also comprises begin beginout canisters inside which envelopes are placed for the safe recovery of the filters, and differential pressure switches which control the exhaustion of the aforesaid filters.

At the base of hopper 5, ? placed a four-axle knife-type shredder 7 equipped with an automatic anti-blocking system, which chops up the waste reducing it to a minimum size.

Shredder 7? equipped with at least one lit inside so that a sliding grid, which determines the desired size of the size of the waste, can be easily replaced, as well as? removed for its maintenance, without the need? to dismantle the entire system. In a preferred version, the at least one access ? consisting of a pair of doors, equipped inside with rollers to facilitate the sliding of the grate. Furthermore, the shredder 7 ? equipped with four shaft knives with cutting elements consisting of sharp-edged discs equipped with hooks whose function is ? that of hooking the waste and conveying it towards the cutters mounted on two or more? counter-rotating drive shafts that provide for the clean cut of the material.

During the process of reducing the waste by the shredder 7, a sodium hypochlorite solution is atomized inside the hopper 5, suitable for disinfecting its walls, the blades of the shredder and, at the same time, to counteract the lifting of harmful dust , which are generated during the waste reduction process inside the shredder 7.

The shredded waste, passing through a grid located below the shredder 7, reaches a storage chamber 8, equipped inside with a ?????????? ???????????????????????????????????????????????? ??? ?

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flat-bottomed agitator, where below? positioned an inlet auger 9, suitable for transferring the shredded waste collected, inside a sterilization autoclave 10.

The storage chamber 8, which has the function of accumulating and homogenizing the waste shredded by the shredder 7, is equipped with loading/unloading sensors which have the function of communicating with a PLC which manages the introduction of the waste inside the hopper 5.

The sterilization cycle takes place inside the sterilization autoclave 10 where, once the shredded waste is loaded by an inlet auger 9, it is hermetically closed by a shut-off valve and starts a thermal cycle with saturated steam.

The saturated steam, produced by a steam generator 11, is conveyed inside the sterilization autoclave 10 to invest the shredded waste while the latter is contextually mixed by a mechanical stirrer, preferably of the spiral type, moved by a motor external 19, which improves the diffusion of saturated vapor in the waste mass. The combined action of the flow of saturated steam and the mechanical effect of agitation of the mass of waste, ? suitable for causing the conditions of 165°C at 6 bar to be reached inside the sterilization autoclave 10, such as to guarantee a reduction of the bacterial load of not less than 10-6 S.A.L. as required by UNI 10384/94.

The external motor 19 works in both directions, i.e. clockwise for unloading the sterilized waste and counterclockwise for mixing during the sterilization phase.

The sterilization autoclave 10 ? cooled at the end of the waste treatment, by a liquid ring vacuum pump 23 and ? preferably equipped, inside, with a compartment suitable for housing vials containing bioindicators, in order to comply with the provisions of the UNI 10384/94 standard.

At the end of the sterilization cycle, atmospheric pressure is restored inside the sterilization autoclave 10 by means of the activation of a discharge valve, which discharges the saturated steam from the sterilization autoclave 10, through a condenser tube bundle 12, where, thanks to the action of a cooler 13, it can condense and be reused for a new sterilization cycle.

Once the saturated steam has been discharged, the sterilization autoclave 10 is depressurized and cooled.

The sterilized, dried and cooled waste is unloaded from the sterilization autoclave 10 and collected by a unloading auger 14 which will provide to transport and unload it, through the opening of a manhole cover 21, inside an outlet container 15, positioned on said unloading platform 16, equipped with an electronic scale, for checking the weight reduction achieved in the treatment .

The individual components of the system are positioned and installed on a self-supporting and modular frame 22 in iron sections. This allows for a simple and rapid assembly with minimum dimensions such as to facilitate installation in healthcare facilities of public and private hospitals and waste treatment centres.

The plant 1 object of the invention ? equipped with 20 ladders for easy maintenance, inspection and control of the plant 1 and 24 safety barriers.

The plant 1 ? otherwise? equipped with a reverse osmosis purification plant 25, for the purification of the leachate resulting from the sterilization process.

The plant 1 object of the invention carries out its cycles in a completely automatic way by means of sensors and PLCs managed by an electric panel 17 which has the task of coordinating and managing the functioning of all the elements that make up the plant 1.

Claims (14)

1. High efficiency automated system for the sterilization of infectious risk medical waste (1), including: - an automatic tipper (4) for bins (2), - safety barriers (24), - proximity sensors? for the correct management of loading and unloading of infected waste, - a tipper equipped with a load scale platform (3) for managing the incoming weight of the infected waste, characterized by the fact that the automatic tipper (4) transfers the infected waste present inside a dumpster (2) and according to sequences programmed, inside a hopper (5), equipped with filling sensors, connected to a filter unit (6) and equipped, at its base, with a shredder (7) suitable for filling a storage chamber with shredded waste ( 8), the latter in turn, equipped with an inlet auger (9) suitable for transferring the shredded waste to an autoclave (10) inside which the waste itself is treated through the mechanical action of a spiral and with saturated steam produced by a steam generator (11), called autoclave (10) being, at the end of the treatment of the now sterilized waste, cooled by a liquid ring vacuum pump (23) and brought to the desired temperature, the steam being, in turn, conveyed inside a shell and tube condenser (12) to be condensed by means of a cooler (13) where, by means of a reverse osmosis purification plant (25), ? stored in tanks equipped with a series of sensors and probes that analyze the properties? of the water contained inside the tanks themselves. 2. High efficiency automated system for the sterilization of infectious risk medical waste (1), as per claim 1, characterized in that the sensors and probes which analyze the properties? of the water inside the tanks, are suitable for sending the acquired data to an electrical panel (17) and, from these, after being treated by a proprietary algorithm, to the reverse osmosis purification plant (25). 3. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as per the preceding claims, characterized in that, together with the recovery of the steam to be used for a new sterilization cycle, by means of a PLC, open a manhole cover (21), to allow the sterilized waste to enter the unloading auger (14) which, in turn, will transfer it? in an outlet bin (15). 4. High efficiency automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that it reaches a sterilization level of 10-6 S.A.L. subjecting the shredded waste to the joint action of mechanical agitation and saturated steam at conditions of max 165°C and 6 bar. 5. High efficiency automated system for the sterilization of infectious risk medical waste (1), as per claim 1, characterized in that, at the end of the cycle, the saturated steam is condensed by means of a shell and tube condenser (12) managed from a cooler (13), to be recovered and treated in order to obtain distilled water to be stored in tanks to be filtered by reverse osmosis and recirculated for the generation of new steam. 6. High efficiency automated system for the sterilization of infectious risk medical waste (1), as per claim 1, characterized in that the shredder (7), of the knife type with four shafts with cutting elements consisting of discs sharp-edged with hooks, ? equipped with at least one access consisting of a pair of doors equipped, inside them, with rollers for the sliding of a grid which determines the size of the waste. 7. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as claimed in claims 1 to 4, characterized in that the filter unit (6) comprises in sequence, a metal mesh filter, a pre-filter, an H-14 efficiency HEPA filter and a rigid pocket type activated carbon filter, it also includes begin beginout canisters inside which bags are placed for the safe recovery of the filtering unit (6), and pressure switches differentials that control the exhaustion of the aforementioned filters and a suction fan. 8. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that the storage chamber (8) ? equipped with a flat-bottomed propeller agitator and filling sensors to control, through the intervention of the PLC, solenoid valves which manage the introduction of a new load inside the hopper (5). 9. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that the sterilization autoclave (10) ? equipped inside with a compartment suitable for housing vials containing bioindicators. 10. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that the vials housed inside the sterilization chamber (10) contain a strip of spores of Geobacillus Stearothermophilus. 11. Highly efficient automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that the mechanical element which agitates the waste inside the sterilization autoclave (10) ? of the spiral type, moved by an external motor (19) which works in both directions, i.e. clockwise for unloading the sterilized waste and counterclockwise for mixing during the sterilization phase. 12. Automated plant for the sterilization of medical waste with high efficiency (1), according to the preceding claims, characterized in that the average calorific value of the sterilized waste dried and reduced in volume treated by the plant (1) ? suitable for powering thermal systems that use waste-derived fuels. 13. High efficiency automated system for the sterilization of infectious risk medical waste (1), as claimed in the preceding claims, characterized in that the shredder (7) reduces the volume of the waste by 80%. 14. Automated system for the sterilization of medical waste with high efficiency (1), according to the preceding claims, characterized in that it is equipped with an electrical panel (17) connected to each component listed in the preceding claims, and equipped with one or more remote displays and located in the points according to the UNI 10384/94 standard, the control panel (17) being also connected to the company network and/or connected to an external server, allowing to create alert messages and consequently to intervene in remote management and remote control of the entire plant.