WO2009019570A2 - Apparatus for the sterilization and inactivation of hospital garbage by means of either uvc rays or ozone - Google Patents

Abstract

Invention deals with an apparatus and methodology for treatment of hospital garbage. The apparatus is privided with a series of modules aiming at making inactive microorganisms potentially present in the hospital garbage. The mentioned modules plan the use of UVC rays, vapor and ozone.

Description

Apparatus For The Sterilization And Inactivation, By Means Of An Action Either With UVC Rays Or Ozone, Of Microorganisms Included In Hospital Garbage And Consequent Treatment

Invention deals with an apparatus and a method for degerming and biological sterilization of special hospital garbage, which have a special infective risk, in order to get inactivation of pathogenic microorganisms, virus and sporogenic bacteria in it contained, in this way it is obtained a garbage which can become assimilated to city garbage, and thus transportation can be carried out and their unloading in special places, without any risk of contamination or infection.

This apparatus and corresponding used methodology, in compliance with what is foreseen in laws which are in force (UNI 10384), it was studied in consideration of the extreme dishomogeneity type of treated material and practical impossibility to determine species of microorganisms and their concentration. According to what is foreseen by this invention, infected hospital garbage, can be subjected to two different types of treatment and, more exactly, it can be subjected to a thermal sterilization treatment by means of UVC radiation action, which can be generated by suitable lamps, which send out necessary energy to guarantee inactivation of included microorganisms, or, as an alternative, apparatus can go on to garbage sterilization by means of a chemical oxidizing action by means of providing ozone, in a liquid or gaseous state, directly on same garbage.

Damage caused by UVC radiation action or, as an alternative, by ozone is irreversible and it has consequence to inhibit growing functions and multiplication of microorganisms which are present in garbage which must be sterilized. As it is well known, hospitals, analysis laboratories, and also all other organizations connected to sanitary service, produce a great quantity of potentially infective garbage, as for instance bandages, syringes, cannulas or other materials which come in contact with patients who are potentially infective, or also infective garbage like bacteria, virus, spores etc.

Above mentioned hospital garbage, until their delivery to proper centers where their thermal destruction is foreseen, require special actions in order to avoid that the same can be a cause of infections. A well-known technology, in order to avoid infection risks, is that of gathering said garbage in containers, that, once they are filled up, they are closed in a airtight way, they are deposited in a proper deposit center, inside hospital area and periodically picked up by specialized firms that provide to their transfer to special plants that provide for their thermal-destruction. Further well-known methods, provide for hospital garbage sterilization either by means of chemical agents that act when they come into contact with infectious garbage or by means of radiations of γ rays on the same.

These methods allow treatment of special garbage having a small volume only, besides they do not guarantee a sufficient prevention against infections. Besides they have a further inconvenience as a consequence of the disposal of chemical components used in the treatment.

A further inconvenience is due to cost of disposal of special garbage and of expenses for their incineration, costs which are much higher to those necessary for the disposal of domestic garbage. Purpose of present invention is that of solving above described inconveniences by providing an apparatus which has:

- possibility to apply treatment directly in garbage production places, by eliminating all possible impact on population, on workers and on environment which are interested in various phases of moving and of transportation of the same garbage;

— accurate control of quantities and typology of produced garbage with a strong decrease of disposal costs;

- reduction, of about 80%, of garbage volume sent to disposal owing to their compactness and their grinding (both starting one, during their loading, and final one, when it is unloaded);

— elimination of any kind of special container for transportation, which are available only from specialized sale shops and at a high cost;

~ self-sufficiency and easiness of installation; really, the same one, of a standing type or to be loaded in a cart, it is fully enclosed in a container for its installation also in outside environment. This apparatus requires only one electrical connection, 380V, three-phase, and a simple water supply; there is no production of liquid garbage, it is not required a connection to urban sewers. In the case of the type that can be put on a cart, a tank and a current generator, is sufficient to guarantee complete self-sufficiency of apparatus; ~ lack of risks, by administrative and sanitary agencies and by organizations making the garbage , which can come from legal and penal liabilities in relation to the correct final disposal of special garbage, possibly infected.

These and further purposes are reached by apparatus for the sterilization and inactivation of microorganisms which are included in hospital garbage and in corresponding procedure included in present invention, which is described in a preferred execution, which is not confined by further developments within the range of the same patent, with help of tables with enclosed drawings that describe following figures: fig.l a total view of apparatus in execution with operation by UVC rays; fig 2 a total view of apparatus in execution with operation by ozone; fig.3 the first sterilization module in execution which uses UVC rays; fig.4 the first sterilization module in execution using ozone; fig.5 a side view of storage hopper and of primary grinding device; fig.6 a front view, with some parts partially taken out, of hopper and grinding device of fig. 5; fig.7 a cross section view of screw conveyor for garbage transfer; fig.8 a cross section view of sterilization chambers which are assembled on a rotating table; fig.9 a cross section view of a single sterilization chamber; fig. 10 an outside view of a sterilization chamber. With reference to drawing tables which are enclosed, it is here described apparatus for the sterilization and inactivation of microorganisms which are included in hospital garbage and related procedure included in present invention.

In details, with reference to figures 1 and 2 apparatus includes in its assembly a series of modules each of them with a specific function to carry out and in details, in fig 1 it is shown loading module and for a first grinding of garbage, in fig.2.1 first sterilization module by means of UVC radiations, in fig 2.2 first sterilization module using ozone, and in 3 module including second grinding device and sterilization chambers by means of saturated vapor under pressure, in .4 aspiration and filtering module for fumes and at last in 5, module for vapor production. Loading and primary grinding module includes in first place a hopper 6 provided with an input opening 6a, through which special garbage to be treated is inserted, and this includes a large door 7 which, once garbage is inserted, is hermetically closed by means of action of a pneumatic piston 8. In order to avoid adventitious escape of gaseous bodies, which can be potentially infected, inside hopper 6 is kept continuously in depression by means of an aspirator 9.

Air sucked in by aspirator 9 is sent to an activated charcoal filtering device 10, which disinfects and deodorizes it.

Loading hopper 6 is also provided with a series of nozzles 1 1 from which it is possible to send, in the same, vapor in order to sterilize it before any maintenance action and in any case at any stop of apparatus.

Inside hopper 6 a grinding device 12 is present which starts to grind garbage immediately after pneumatic closure of large door 7; during this phase apparatus is fully insulated from outside environment. Grinding device 12 is substantially made up of two or more rotating shafts, connected between themselves by a transmission, which carries steel blades, capable to grind any kind of material thus reducing its volume.

Outside the grinding device, an unloading hopper 6b is located, that allows passage of garbage to first phase of treatment or, in other words, in module 2.1 or 2.2 . Also in this case, along walls of hopper 6 a few nozzles 1 1 are located in order to send sterilizing vapor before any maintenance action and at every production stop of apparatus.

Nozzles 1 1 are connected, by means of vapor general circuit , to vapor production module 5. At module 1 output average volumetric reduction of garbage inserted is of 5 - 10 times that at the beginning.

With reference to figures 1 and 3 it is described in the following module 2.1 of sterilization of garbage by means of UVC radiations. During this phase, garbage coming from primary grinding operation, is conveyed under a series of fluorescent lamps 13, which generate UVC radiations and as a result a heat source directly applied to garbage and to microorganisms in it contained.

Limited penetrating effect of UVC radiations make preceding grinding operation very important and the resulting mixing of garbage, which is obtained by moving material to be treated through a series of belts 14, one over the other, which are present in module

2.1.

Well designed deviators 15a provide a better distribution of garbage on belt and therefore a better efficiency of radiations.

Transportation belts 15, which are made of plastic material or in cloth and plastic material, or in any case in any kind of material which is high temperatures and direct

UVC action resistant, can also be of vibrating type in order to improve mixing of garbage.

Module 2 is provided with visible inspection windows designed air tight , by means of effective materials that do not allow escape of radiations or of ozone, otherwise harmful to operators and to maintenance people.

In a second execution 2.2 module of first sterilization is provided with a series of nozzles 16 that send out ozone in liquid or gas state, along first belt.

Apparatus in a preferred execution has a first sterilization module, provided with a system of UVC radiations generation and of nozzles to send out ozone. In any case, it is understood that, in standard working conditions, only one of the two systems will operate, but never both at the same time.

As an alternative apparatus may be provided with exclusively either of one or of the other sterilization type. At the output of treating chamber 2 both that it provides treatment of garbage by means of UVC radiations or of ozone distribution, it is located a loading hopper 17, for sending garbage R in conveyor 18.

Conveyor, screw type, 18 is mainly made up of an external cylinder 19 and of an inside propeller 20 with a shaft, powered by a direct current motor M with variable speed. The same has the function of transferring garbage R and of its mixing at the same time.

Both external cylinder 19 and inside propeller 20 are designed in stainless steel, in order to provide necessary specifications for resistance to possible corrosive actions.

Further, screw type conveyor 18 is mounted in an inclined position, in order to provide a bigger length of treatment, with same general dimensions, and in order to take advantage of the height of output opening in order to install components coming after ( secondary grinder and sterilization chamber ).

Control of rotation speed of screw 20 is provided by means of a frequency changing device (inverter), directly controlled by a PLC ( included in electrical control unit) as a function of garbage load put into apparatus, so that it is always guaranteed necessary treatment, considering time required, for a complete sterilization and inactivation of same garbage R.

Along screw conveyor 18, temperature probes are provided, and also sensors to signal breakdowns and operation problems (revolutions control, pressure switches, thermometers, and so on). It is important to underline that oxidant and sterilizing action by ozone, requires a minimum time ( which can be estimated about 15 minutes); besides, ozone being a very unstable gas, after this period of time is totally converted in oxygen, and it does not leave any type of solid or liquid slag, or again no type of obnoxious gas to be disposed. As already mentioned above, screw conveyor 18 unloads garbage R in a second grinder 21 which provides for further grind garbage and send it to one of sterilization chambers 22, located on rotating table 23.

At time when one of sterilization chamber 22 is full, rotating table 23 turns and locates, in connection with lower part of second grinder 21, a further sterilization chamber 22, empty, ready to receive a further quantity of garbage R. At the same time of table 23 rotation, in sterilization chamber 22, already previously filled up, sterilization process starts.

Sterilization chamber 22, in a number of one or more, is substantially made up of metallic containers in stainless steel, with a double chamber (that is with an intermediate gap), which operate by means of saturated vapor under pressure. Garbage F is therefore subjected to a thermal stress, in other words it is maintained, for minimum time of 10 to 15 minutes, in sterilization chamber 22 and at a pressure of 1 ATM which allows to increase temperature of vapor to about 121°C. Only when higher cover 24 is in the closing position, vapor can be sent to chamber 22, and, at the same time, air which is present in the same, is expelled until inside required pressure is obtained. Only at this time, or when vapor is saturated, a timer will measure real sterilization time. Pressure and temperature inside sterilization chamber 22 are continuously under control by suitable instrumentation with visualization (thermometers, manometers, air pressure switches, thermostats).

Chamber 22 is provided with breathing valves for vapor and maximum pressure valves, suitably set to values sufficient to guarantee necessary security conditions. Besides, a vacuum pump is also provided which, at the end of sterilization time, is capable to eliminate vapor which is present in inside parts, thus drying garbage. Finally, suitable suction intakes are also present, capable to get hold of fumes and vapors emissions, and then convey them towards a destruction filter with active charcoal 10.

Sterilization chambers 22 are located on a rotary table 23, so that, at end of filling up of one chamber, there is an empty one, ready to take a new quantity of garbage R. Vapor sucked in by pump is sent to a condenser, for the purpose of taking it again to a liquid state, in order to be again used in vapor generator (obviously by integration with water coming from an outside source of supply).

At the output of sterilization chambers 22, garbage, at this stage already sterilized, is directly loaded into metallic containers C, ready to be taken and sent to a dumping area. As already mentioned, apparatus provides that all fumes and vapors, which are sent out during garbage loading and during primary grinding operations, are suitably sucked by means of an axial centrifuge fan 9 and treated, before final introduction into atmosphere, by a first mechanical filter, and afterwards by a second filter, operating with active charcoal 10. Apparatus is also provided with a system of photovoltaic panels, located in higher part of external casing, capable to supply necessary electric supply for the operation of all auxiliary services.

Vapor circuit is essentially made up of a vapor generator 5, suitably designed, such as to be able to generate necessary quantity of vapor at temperature and pressure required. The whole circuit of transportation and conveyance of vapor, is made up of copper tubes or stainless steel ones, fully coated by thermo-insulating protective covers, in order to avoid heat dissipation and thus improve efficiency of apparatus. Pneumatic circuit is made up of an air compressor P, provided with a suitable tank and of a series of tubes in plastic material of supply to users, made up of linear and rotating pneumatic cylinders, like cylinder of opening door 7, rotating cylinder for opening of garbage disposal input 25, and valves for vapor sending.

Compressor must be capable to generate air at a pressure of 6 - 8 bar, while tank must have a capacity of about 60 liters. All process phases, physical parameters that characterize it, time required by sterilization process and movements of single parts which make up this apparatus, are controlled by a processor (PLC), with its own software, which must process inputs coming from sensors and from instrumentation of which this device has, in order to generate an output which has the shape of commands or of signals of correct operation or of machine failure.

In details parameters which must be managed are the followings:

— presence of ozone inside screw conveyor in a suitable concentration, in order to avoid that ozone be present inside sterilization chambers;

- time of stay of garbage in a single sterilization chamber; — opening and closure of discharge valves and of containers covers and of sterilization chambers;

~ speed of screw conveyor for garbage transportation;

— pressure and temperature inside containers and especially of sterilization chamber/chambers;

— speed of grinding devices both primary and secondary with control by an inverter.

As already described above, apparatus is capable to use two different types of sterilization coupled to that using saturated vapor under pressure: first one consists of sending UVC radiations on garbage, second one provides a treatment by means of use of ozone in a liquid or in gas state.

Briefly, sterilization process of hospital garbage provided by present apparatus is the following:

— introduction of garbage in hopper 6;

— first grinding of garbage by means of a grinding device 12 which decreases volume of this one by about 5 to 10 times;

— unloading of garbage inside module 2.1 or 2.2 according to whether machine was arranged to garbage treatment by means of UVC radiations or by means of ozone;

— in the case garbage was treated by means of ozone, this one will continue its sterilizing action also inside screw conveyor 18 which will also provide a mixing action of same garbage R. In order to achieve an efficient sterilization of garbage, minimum time of stoppage of same one in contact of ozone, inside module 2 of the first sterilization and of screw conveyor 18, must be of about 15 minutes;

— second grinding for a further reduction of garbage volume R; - going through of garbage R in a sterilization chamber 22, inside which garbage continues to receive a thermal treatment, by means of action of saturated vapor under pressure with a pressure of 1 ATM, which allows to reach a temperature of 121°C for a minimum time of treatment of about 10 to 15 minutes. It is necessary now to underline that it is not the pressure to cause microorganisms death, but it is high temperature, which can be reached in a vapor state at a pressure which is higher than atmospheric one.

At the end of screw conveyor 18 ozone will be completely converted in oxygen without in the meantime any production of waste.

Claims

1. "Apparatus for the sterilization and inactivation, by means of an action either with UVC rays or ozone, of microorganisms included in hospital garbage and consequent treatment", characterized by fact that following modules are included :

-- a hopper (6) including a grinder device (12) in which special garbage to be treated is included;

— a first sterilization module (2) which operates by means of action of UVC rays or by means of ozone; ~ a screw conveyor ( 18);

-- a module (3) including a grinding unit (21) and one or more sterilization chambers (22) which operate at times placed one over the other;

— a module (4) which includes inhaling devices (9) and filtering ones (10) of fumes and of exhalations which are sent out during the sterilization cycle of garbage;

— a module (5) which includes devices for the production, generation and transferring of vapor to each one of apparatus units.

2. Device for the sterilization and inactivation of microorganisms contained in hospital garbage as already seen in claim 1, characterized by fact that hopper (6) includes a large door (7), opening and closing of which is driven by piston (8) and a series of nozzles (1 1) for introduction of vapor in the same one.

3. Apparatus as already seen in claims 1 and 2, characterized by fact that grinding unit (12) is a type with a double rotating blade, which have contrary rotations.

4. Grinding unit as already seen in claim 3, characterized by fact that grinding unit (12) can be of any type suitable to grind hospital garbage.

5. Apparatus according to previous claims, characterized by fact that module (2.1) of the first sterilization and inactivation of microorganisms which are present in hospital garbage, includes one or more conveyor belts (14) one over the other, each of them overlapped by a series of fluorescent UVC lamps (13) (in other words lamps which emit radiations in ultraviolet field, with a short wavelength, included between 200 and 280 nanometers), and by devices (15) in order to allow a better distribution of garbage over the belts (14).

6. Apparatus subject of previous claims, characterized by fact that, in a further execution, module (2.2) of a first sterilization and inactivation of present microorganisms in hospital garbage, includes one or more overlapping conveyor belts (14) of which the first one is provided with nozzles (16) in the upper part for sending ozone over the same one, and by devices (15) which allow a better garbage distribution over belts ( 14).

7. Module of first sterilization subject of claims 5 and 6, characterized by fact that it includes devices either for the sterilization by means of UVC rays, or by ozone.

8. Module subject of claims 5, 6 and 7 characterized by fact that belts (14) can be of a vibrating type.

9. Apparatus subject of preceding claims, characterized by fact that transfer from module (2.1) or (2.2) to grinding device (21) is carried out by a screw conveyor (18).

10. Apparatus subject of claims 1, 2, 3, 4, 6, 8 and 9, characterized by fact that oxidation process caused by introduction of ozone takes place in module (2) and in screw conveyor (18) and for a time of about 15 minutes.

1 1. Apparatus subject of preceding claims, characterized by a module (3) including one or more sterilization chambers (22) which are in operation on a rotary table

(23) inside of them saturated vapor is introduced under pressure and a grinding device (21) of a type which is capable of grinding treated garbage. Sterilization chambers (22) are provided with a gap, and also of a loading cover (24) and of a discharge device (25) from which treated garbage R falls in proper gathering containers C.

12. Process for the sterilization and inactivation of microorganisms contained in hospital garbage characterized by following phases:

— introduction of garbage into hopper (6) and subsequent closure of big door (7); ~ grinding of garbage by means of action of grinding device (12) with consequent reduction of garbage volume of about 5-10 times ; ~ introduction of ground garbage in module (2.1) which provides to its first sterilization by means of UVC rays or as an alternative in module (2.2) for its sterilization by means of ozone; — transfer of garbage R from module (2) to module (3) by means of screw conveyor (18);

— second grinding of garbage R, sterilized, in order to further decrease its volume by means of grinding device action (21); ~ stopping of garbage R in a sterilization chamber (22) in contact with saturated vapor under pressure;

~ rotation of rotating table (26) and unloading of garbage R, ready to be eliminated in disposal areas in a proper container C.