This invention relates to a device for incinerating hypodermic syringe needles and like sharp objects.

The safe disposal of sharps, i.e. hypodermic syringe needles and similar sharp objects, represents a considerable problem. Syringe needles are disposable objects and generally are used only once. Consequently, each day, vast numbers of used needles contaminated with blood, drugs etc. are generated and require disposal in a safe and hygienic manner.

Devices are known which can incinerate needles and typically such devices make use of a pair of electrodes across which is applied a voltage Bringing a needle into bridging contact with the two electrodes causes a large current to pass through the tip of the needle thereby melting it. By advancing the needle into the machine, the needle is progressively destroyed.

Known incineration device make use of a pair of

electrodes which are biased towards each other, e.g. by means of a suitable spring, the combination of the spring biasing and appropriately sited sloping guide surfaces serving to ensure that a needle inserted into the incineration device will make contact with both electrodes. However, a problem with known devices has been a tendency for needles to jam in the device, thereby requiring the dismantling of the device in order to extract the needle. Furthermore, some such devices require adjustment to accommodate differing needle sizes and such adjustment of course renders the incineration process more time consuming and inconvenient.

It is an object of the present invention to overcome such problems.

Accordingly, in a first aspect, the invention provides a device for incinerating a needle and like sharp objects, which device comprises first and second electrodes; the first electrode being mounted for rotation about an axis; the second electrode being mounted adjacent the first electrode so as to define a gap therebetween; a motor for rotating the first electrode about its axis; guide means for guiding the needle or like sharp object towards a position whereat it bridges the gap between the electrodes; and means for delivering sufficient electrical current to the electrodes to cause the fusion and destruction of a portion of the needle or like sharp object in the region between the electrodes.

The first electrode generally will have a

cross-section corresponding to at least a sector of a circle, and preferably a full circle.

The first electrode can be mounted for partial or complete rotation, and for either continuous or reciprocating rotation.

Preferably the first electrode is of substantially circular cross-section and is mounted for continuous complete rotation about the axis thereof.

The second electrode can be provided with guide surfaces for guiding the needle or like sharp object past or through said second electrode and towards the first electrode. Advantageously, the guide surfaces are defined by a slot in the second electrode, the slot having opposed surfaces which converge in the direction of the first electrode. Preferably the slot is a closed slot.

The second electrode can have a concave arcuate surface arranged to confront an arcuate surface of the first electrode.

The second electrode preferably is mounted for pivotal movement whereby an edge of the said second electrode can be moved towards and into contact with the first electrode. Most preferably, the second electrode is resiliently biased away from the first electrode. The second electrode can be arranged to be urged into contact with the first electrode by applying pressure with the needle or like sharp object. In such manner the second electrode can act as a scraper to remove materials from the surfaces of the first and second electrodes.

The device generally is provided with an entry chamber for receiving the end of a needle or like sharp object, the entry chamber being provided with sloping or curved guidewalls for guiding the said end towards the second and first electrodes. The entry chamber is preferably provided with anti-sparking means for preventing sparks from passing out of the device through the entry chamber. The anti-sparking means can advantageously take the form of a brush having bristles directed inwardly from the periphery of the mouth of the entry chamber.

The incinerator device preferably is provided with a timer which is operable to initiate and terminate a timed period during which the first electrode is rotated and a voltage is applied to the electrodes.

The current supplied to the electrodes can be D.C. or A.C. current, but preferably it is alternating current.

The invention will now be illustrated in greater detail, but not limited, by reference to the particular embodiment shown in the accompanying drawings, of which:-

Figure 1 is a side elevation of an incinerator device according to one embodiment of the invention;

Figure 2 is an end elevation from direction A in Figure 1; Figure 3 is a sectional elevation along line I-I in Figure 2;

Figure 4 is an enlarged isometric view of an electrode illustrated in Figures 2 and 2; and

Figure 5 is a sectional view along line II-II in Figure 4.

Referring now to Figure 1, it can be seen that the incinerator device comprises a casing 1 formed of fabricated sheet metal, with a hinged door or flap 2 at one end thereof which can be secured by means of latch 3.

The interior of the casing 1 is divided by wall 4 (shown as a dotted line) into two compartments 5 and 6.

Compartment 5 contains a transformer (not shown) for transforming mains voltage to a voltage of approximately 4.5 volts, to provide a current oscillating between 20 and 40 Amps. Also contained within compartment 5 are an electric stepper motor (not shown) for rotating a shaft upon which an electrode is mounted, a timing circuit and associated electrical wiring and circuitry. The power supply to the device is controlled by on/off switch 7 mounted on a side wall 9 of the casing. Also mounted on the side wall 8 are an overload trip switch 9, a button 10 which activates the timer and initiates the incineration operation, and auxiliary needle port 11 which, in this embodiment is blanked off. Secured to the top wall 12 of the casing is a carrying handle 13.

The interior layout of compartment 6 can be seen from Figures 2 and 3. Thus compartment 6 contains a first electrode 14 of circular cross-section, which is mounted for rotation about shaft 15. Shaft 15 is driven by the electric motor in compartment 5. A second electrode 16 is mounted on pivot mounting 17 closely adjacent first electrode 14 so as to define a gap 18 between the two electrodes. Electrode 16, which is of generally arcuate

cross section, is shown in more detail in Figures 4 and 5. The electrodes 14 and 16 are formed of a chromium copper alloy, a suitable example of which is "Bolt Mac 819" supplied by Thomas Bolton Limited of Froghall, Stoke-on-Trent, UK.

At the bottom of compartment 6 is located a removable tray 19 which is formed of stainless steel and is arranged to collect incinerated needle fragments. Disposed above the tray 19 is an entry chamber and shielding assembly 20 which is supported and held in place by means of two pins 21, 22 extending from the partition wall 4, and located in holes in the inner wall 23 of the assembly 20. The lower part of the assembly 20 is constituted by inner wall 23 and side walls 24 and 25 which serve to shield the interior walls of the casing 1 from sparks and fused needle fragments. The upper part 26 of the assembly 20 comprises a generally cylindrical outer wall 27 with a generally cup-shaped interior wall 28 secured by a weld to outer wall 27. The cup-shaped interior wall 28, which defines an entry chamber 28a, terminates at its lower end in a slot 29. At the mouth of the entry chamber 28a, the wall 28 is provided with an annular recess 30, in which sits a metal ring 32 having an annular channel 33, within which are clamped radially inwardly directed bristles 34 formed of heat-resistant fibre. The entry chamber and shielding assembly 20 can be removed simply by sliding the assembly off of the pins 21, 22.

Figures 4 and 5 illustrate the configuration of the

second electrode 16 which is of generally arcuate cross-section. The electrode 16 is pivotably mounted on the dividing wall 4 by means of mounting 35. The electrode is provided with a guide slot 36, the width of which decreases from top to bottom. The sloping walls 37, which are arranged at an angle α of approximately 50° with respect to each other, function as guide surfaces as will be explained below.

In use, the incinerator device is connected up to a power source and switched on. The timer button 10 is depressed to indicate a timed period of say ten seconds during which the electrode 14 is rotated (in this embodiment at a speed of approximately 160 r.p.m.) and a voltage is applied to the electrodes.

A hypodermic syringe needle is pushed through the brush 33 between the bristles 34 and is guided by curved walls 28 through the slot 29 towards the second electrode 16. The slot 29 and the curved walls 28 are dimensioned such that the needle N is guided towards the aperture 36 in the electrode 16. Guide walls 37 in turn direct the needle N through the aperture 36 and towards the first electrode 14.

As the needle N makes contact with the surface of electrode 14, the electrical circuit is completed and a current of 20-40 A passes through the needle tip, thereby causing melting of the tip of the needle N. As the needle is advanced into the incinerator, it is thus progressively destroyed, leaving only a small stub which in the great

majority of cases is sealed.

As the syringe is advanced into the entry chamber 28a, a point is reached when the hub end B of the needle comes into contact with the electrode 16. Further pressure on the syringe at this point results in the electrode 16 pivoting about mounting 17 and the end 38 of the electrode 16 being urged towards the first electrode 14. Bringing the end 38 of the electrode 16 into contact with the electrode 14, provides a cleaning action as any molten metal or other waste material on the electrode 14 or electrode 16 is scraped from its surface.

Thus, a significant advantage of the incinerator of the present invention is that the electrodes are substantially self-cleaning, and consequently would be expected to enjoy a longer life.

A further advantage of the rotating electrode arrangement is the speed of incineration. Typically, destruction of a needle takes no more than a few seconds.

Furthermore, melted needle fragments are swept away from the electrode by virtue of its rotating action thereby reducing the possibility of jamming. The needle fragments fall into tray 19 from which they can be disposed as convenient.

It will readily be apparent that numerous alterations and modifications could be made to the embodiment illustrated without departing from the principles underlying the invention, and all such alterations and modifications are within the scope of this application.