The present invention relates to an incinerator, and in particular to an incinerator for incineration (thermal degradation) of electrically conductive hollow articles such as medical needles.

Incinerators particularly adapted for the incineration (thermal degradation) of potentially hazardous used medical needles are disclosed in, for example U.S. Patent Specification 4628169 and South African Patent Specification 89/8607. Both documents disclose incinerators for thermally degrading spent syringe needles using a pair of spaced electrical contacts to pass a high current through an interposed medical needle.

An improved incinerator has now been devised which may be used for such purposes.

According to a first aspect of the invention there is provided an incinerator for incinerating a substantially hollow article which incinerator includes crimping means actuable to mechanically plastically deform a portion of said article.

Advantageously the crimping means comprises a pair of crimping contacts or jaws which are movable relative to one another between a first position in which the article is crimped (i.e. plastically deformed) therebetween and a second position in which the crimping contacts are spaced from the article. Typically the hollow article is crimped to provide a substantially sealed termination or end to the hollow article.

It is preferred that the incinerator according to the first aspect of the invention is further provided with a second pair of contacts, these being electrically conductive and spaced from one another defining a gap. The second pair of contacts are typically coupled to power supply means such that an electrical potential difference may exist across the gap between the second pair of contacts. The second pair of contacts are arranged such that when the hollow article is introduced into the incinerator, and where the article comprises an electrically conductive material, the gap between the second pair of contacts is bridged and a current flows through the portion of the article bridging the second pair of contacts. Where the current flowing through the bridging portion of the article is sufficiently high, this portion of the article will be thermally degraded (incinerated) e.g. by melting and thermal oxidation.

Advantageously, the crimping means is arranged to crimp (plastically deform) a portion of the article immediately adjacent an incinerated portion.

Typically, the pair of crimping contacts will also comprise a pair of electrically conductive contacts and be arranged for electrical connection to power supply means which may be the same as, or different to, the first mentioned power supply means. An electrical potential difference can therefore exist between the pair of crimping contacts, and when the hollow (conductive) article is crimped, a current flows through the crimped portion of the article causing the crimped portion to be welded, thereby ensuring a good seal is formed.

Advantageously, where the hollow article is elongate (e.g. a medical needle) the crimping means will be spaced from the second pair of contacts in the longitudinal direction of the article.

Typically, in the case where the crimping contacts are electrically conductive and spaced from the second pair of contacts, a current is caused to flow through the portion of the hollow conductive article between the crimping contacts and second pair of contacts causing that portion of the hollow article to be incinerated (or pyrolysed).

It is preferred that the crimping means is actuated automatically at a predetermined stage in the incineration process, advantageously being triggered when a predetermined length and gauge of the article has been inserted into the incinerator. Typically, insertion of the article into the incinerator causes a movable plunger to complete a circuit when a predetermined plunger position is reached. Completion of this circuit typically causes an electric motor or the like to actuate the crimping means. The plunger may for example contact the actuation arm of a microswitch which actuates a driving motor/leadscrew arrangement to cause a movable crimping contact jaw to move relative to a stationary crimping contact jaw, thereby crimping the article.

Advantageously, when the article has been crimped, the microprocessor and/or integrated circuitry causes an electric motor or the like to actuate the incineration of the remaining article placed between the first and second pairs of contacts. The microprocessor and/or integrated circuitry may for example actuate a driving motor/lead screw arrangement to cause the second pair of contacts to move, and being electrically conductive thus cause the incineration of the remaining said article.

It is preferred that the timing and duration of operation of the crimping means

and electrical energisation of the second (and crimping) contacts is controlled by means of appropriate microprocessor and/or integrated circuitry.

The incinerator is preferably provided with a removable receptacle arranged to collect the incinerated (melted) portions of the article.

Typically, the crimping means, and also preferably the second pair of contacts, are provided in a discrete module separable from the remainder of the incinerator. Where the power supply means is provided in the remainder of the incinerator, the discrete module is advantageously provided with electrical coupling means adapted to cooperatively engage with complementary couplings of the power supply means.

According to a second aspect of the invention, there is provided an incinerator comprising: a) a housing containing electrical power supply means; b) an incinerator module including a pair of electrically conductive incineration contacts defining a gap therebetween, said module being provided with electrical supply coupling means arranged to cooperatively engage with complementary coupling means connected to said power supply means in said housing, said module being selectively removable from the remainder of said housing whereby said complementary coupling means are caused to disengage one another.

Typically the power supply means will be a voltage step down transformer provided internally of the housing. Alternatively, rechargeable batteries may be provided in the housing.

Advantageously, the incinerator module is provided with crimping means as defined above.

The invention will now be further described in a specific embodiment by way of example only and with reference to the accompanying drawings.

Figure 1 is an external schematic view of an incinerator according to the invention mounted on a stang together with a waste container;

Figure 2 is a perspective view of the incinerator of Figure 1;

Figure 3 is a further perspective view of the incinerator of Figures 1 and 2;

Figure 4 is a schematic view of the internal structure of the incinerator of Figures 1 to 3;

Figure 5 is a further schematic view of the internal structure of the incinerator of Figures 1 to 4;

Figures 6A to 6C are schematic and sectional views of a part of the incinerator of Figures 1 to 5;

Figures 7A to 7C are schematic and sectional views of parts of the incinerator shown in Figures 6A to 6C;

Figure 8 is a sectional schematic view of parts of the incinerator shown in Figures 6A to 7C;

Figures 9 A to 9F are schematic and sectional views of parts of the incinerator shown in Figures 6A to 7C showing the sequence of operation of the incinerator;

Figures 10A to IOC are schematic and sectional views of parts of the incinerator shown in Figures 6A to 7C and Figues 9A to 9F.

Figure 11 is a schematic view of the operational electrical circuitry of the incinerator of Figures 1 to IOC;

Figure 12 is a schematic view of a part of the operational electrical circuitry of the incinerator of Figure 11;

Figure 13 is a schematic view of a part of the operational electrical circuitry of the incinerator of Figures 11 and 12;

Figures 14A to 14D are schematic views of parts of the operational electrical circuitry of the incinerator of Figures 11 to 13;

Figure 15 is a schematic view of a part of the operational electrical circuitry of the incinerator of Figures 11 and 14A to 14D.

The incinerator unit, generally designated 80, is typically mounted on a stand 61 which is adapted also to house a general medical waste container 162. The incinerator is particularly adapted for the hygienic destruction of used syringe needles 64 and, since it is portable, the incinerator may conveniently be moved between locations (e.g. in a hospital) where needed.

Referring to Figures 1 to 4 in particular, the incinerator comprises a housing 14 provided with a plunger 5 having a central aperture through which the needle to be incinerated is inserted. The plunger 5 moves downwardly relative to the remainder of the housing to trigger the needle incineration cycle as will be explained in more detail below. The housing 14 is provided with a tray receptacle 23 which fits into aperture 49 to collect

the incinerated needle (in the form of ash) subsequent to the incineration cycle being completed.

Alternatively, where the waste container 162 is used tray 23 may be removed and the incinerated ash may fall directly into container 162.

Power means for the incinerator is provided either by rechargeable batteries 55,56,57 and 58, or a mains connectable electrical voltage step-down transformer 13 having a primary side of 110V or 220V/2.5A and a secondary side of 2.5V/120A. (These are mounted in the interior of housing 14 on support platform 9.)

Status lights 10,15,21,32,33,34, provided on the exterior of the housing enable an operative to ascertain when the incinerator is switched on, when the incineration cycle is in operation, when the incinerator is overheating, when the rechargeable batteries are in need of recharging, when the power is low and when the batteries are fully charged.

The incinerator is provided with a fume filtration system comprising an electrically powered fan 4 arranged to draw air (and fumes/dust) from the incineration zone through a filter board 2 (located in slot 3) to the atmosphere. The filter board 2 includes a filtration sheet 47 adapted to separate the fumes/dust particles from the air exiting to the atmosphere.

Additionally, the incinerator is provided with a liquid crystal display 22 to alternately indicate the quantity of needles incinerated since the rechargeable batteries 55,56,57,58 were last recharged and also indicate the quantity of needles incinerated since the incinerator unit was last serviced.

The incinerator is further provided with the appropriate microprocessor and/or integrated circuitry and thermistors to detect overheating, short circuits between the contact means and low battery power.

Referring to Figure 3, the control/interface panel on the rear of the housing can clearly be seen showing the mains plug socket 51, on/off switch 50 and fuses 52,53 and fuse holders 78,79. Also shown in Figure 3 is the incineration module 30 which is removable from the remainder of the incinerator housing, and described in greater detail below.

Referring to Figures 5 to 10C in particular, when the incinerator switch 50 is switched to the "ON" position appropriate microprocessor and/or integrated circuitry checks that no current is passing through the contact means 84,85,86 (Figures 10A to 10C) and

checks the contacts 11,26,31 and 36 are correctly spaced for receiving a needle.

The incineration module 30 slides into the housing 14 (on guide rods not shown) and electrical contact is made with the power supply means by conductive contact pins (not shown), thereby setting up an electrical potential difference between incineration electrodes 25/26 and 27/11. The structural configuration of the incineration module may be best described with reference to its use below.

A needle 64 of a medical syringe 66 is inserted through the central aperture in the plunger 5. The needle 64 is pushed downwardly until the longitudinal side of the needle touches the incineration electrode 25/26 and the tip of the needle touches the incineration electrode 27/11. At this stage the contact means 84 (see Figure 10A) is completed between electrodes 25/26 and 27/11 across gap 61. By means of appropriate microprocessor and/or integrated circuitry a change in current supplied between the electrodes is detected and a sufficiently high current is passed between the contact electrodes (approximately 100A) such that the temperature of the needle between the contact electrodes is raised to between 800 and 1000 °C and incineration (or disintegration) of the needle between electrodes 25/26 and 27/11 is effected. This process continues (Figures 9 A to 9F) as the needle is pushed down until eventually the needle hub 65 contacts the plunger 5. Since the needle hub 65 is of greater diameter than the aperture in plunger 5, continued downward pressure on syringe 66 causes the plunger 5 to travel downwardly causing the needle to continue its downward passage and incineration of the portions of the needle contacting and intermediate incineration electrodes 25/26 and 27/11 to continue as described above.

Eventually, the base of the plunger contacts and depresses the actuation button of a microswitch 8. The microswitch 8 is connected to microprocessor and/or integrated circuitry which completes a circuit to a stepping motor 67 housed in the incineration module 30. Stepping motor 67 drives a lead screw 37 (via gear train 68,69,70,71) which urges a movable section of module 30 towards a stationary section 12,28,29,31 of the module. The movable section comprises components 35,36. As the movable section nears the stationary section, the portion of the needle 64 immediately adjacent the hub 65 (which has not at this point bridged gap 61 and has therefore not been incinerated) is crimped between crimping contacts 31,36 (see Figure 10B) on the stationary and movable sections of housing 30 respectively. Since the crimping contacts 31,36 are connected to the power supply through

the microprocessor and/or integrated circuitry which detects the diameter of the needle and supplies the appropriate and predetermined power supply to melt (incinerate) the needle, the microprocessor and/or integrated circuitry progressively supplies power to the motor (and thus urges the movable section) and also sufficient power to the contacts.

Once the needle is crimped between the contacts and the circuit between them across gap 62 is completed, the crimped end of the needle is incinerated, effectively ensuring sealing of the (now reduced) end of the needle and preventing possibly contaminating fluids escaping from the syringe 66. After the needle is crimped between the crimping contacts 31,36 the microprocessor and/or integrated circuitry switches on a sufficiently high power to a third circuit between contacts 25/26 and 36 across gap 63. The microprocessor and/or integrated circuitry also switches on the power supply to another electric stepping motor 18 which drives a lead screw 42 (via gear train 20,45,46,90) which urges a movable section of module 30. The movable section comprises 11,17,19,25,26,27,91,92. Thus the portion of the needle extending across the. gap 63 (i.e. below the crimped portion of the needle) is therefore also incinerated (see Figure 10C). The microprocessor and/or integrated circuitry is set to reverse both the motors when the gap 62 between contact crimping electrodes 31 and 36 is approximately 0.05mm. Thus the movable sections (35,36 and 11,17,19,25,26,27,39,91,92) of incineration module 30 move back to their appropriate starting positions. The syringe can then be removed from the incinerator and the microprocessor and/or integrated circuitry resets the system ready for the next needle to be incinerated. The operation of the timing circuitry and motor/power switching is controlled by microprocessors provided on printed circuit board 60 contained within the incinerator housing 14 and on printed circuit board 60 contained within the incineration module 30. Figures 11 to 15 show circuit layouts and printed circuit board configurations of circuit boards 89,60,24,55 which comprise the controlling microprocessor/integrated circuitry referred to above.

Once a needle has been incinerated and crimped (i.e. once the incineration/crimping cycle is complete) the crimped needle 64 (still connected to syringe 66) is removed from the aperture in plunger 5, and the plunger 5 is reset to its starting position under the influence of four biasing springs (not shown).

The syringe 66 which now has only a very short portion of crimped and sealed needle 64 projecting therefrom may then be sent for disposal with the risk of potentially

hazardous fluids escaping from the syringe and needlestick injury substantially reduced. The incinerated material from the needle (comprising of an ash or powder like material) is deposited in the waste tray 23 or a general medical waste container 162 under gravity.

Typically, the electrode (incineration) contacts 26,11,31,36 comprise 90% silver: 10% cadmium which has been found effective in inhibiting fusing (or welding) of the needle 64 to the contacts during incineration. A particularly advantageous feature of the incinerator according to the invention is the facility to completely remove the incinerator module 30 from the remainder of the incinerator for periodic overhaul or cleaning.