GB2300339A

GB2300339A - Apparatus for disposing of hypodermic needles using electrodes in a disposable cartridge

Info

Publication number: GB2300339A
Application number: GB9517056A
Authority: GB
Inventors: Nicholas Constable; David Wong
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-04-26
Filing date: 1995-08-01
Publication date: 1996-10-30
Also published as: GB9517056D0; ZA963139B; KR19990008164A; TW305763B; GB9508516D0

Abstract

An apparatus for disposing of hypodermic needles comprises a main housing 10 and a disposable cartridge 12 releasably secured to the housing 10. The cartridge 12 has an aperture 44 for receiving needles, electrodes 40, 42 for applying a current to a hypodermic needle inserted into the aperture 44 to destroy the needle and a compartment for storing the debris resulting from destruction of needles. The housing 10 has an electrical power supply (18) for applying a voltage across the electrodes 40, 42 of the cartridge 12 and means 24 for causing movement of one of the electrodes in the cartridge to prevent a build-up of debris in the gap between the electrodes 40, 42.

Description

Apparatus for disposing of hypodermic needles Field of the invention The present invention relates to apparatus for disposing of the needles of hypodermic syringes.

Background of the invention Disposal of hypodermic syringes with needles attached, presents a serious risk of infection to the handlers, especially if they should accidentally prick themselves on one of the needles.

Various forms of apparatus have therefore previously been proposed that pass a current through the needles to destroy them. This not only melts down the needles to prevent them from pricking the handler of the waste hypodermic syringes, but also burns off any toxic residue on the needles.

Such apparatus usually have two electrodes that apply a low voltage across a short length of the needle near its tip and the high current that flows melts this section of the needle. The needle is then progressively fed through the gap between the electrodes to melt the whole of the needle down to the collar that is fitted to the syringe.

It is necessary to remove the molten metal away from the gap between the electrodes to prevent a build-up of debris on the electrodes, which could result in a short circuit. One way of doing this is to form one of the electrodes as a rotating disk or drum driven by an electric motor. Another way of avoiding a build-up of debris on the electrodes is to provide two mutually inclined stationary electrodes and to move the needle along the tarring gap between them.

In all such apparatus, the compartment housing the electrodes eventually fills up with debris and must be emptied and sterilised. Hitherto, removing the debris that accumulates in the compartment housing the electrodes has proved a difficult and time consuming task. Furthermore, it has involved contact with the debris. Incineration of the needles occurs within the apparatus and the infected material togther with any aerosol or dripped product from the syringe will infect the interior of the apparatus as well as the remaining debris.

The electrodes that are used to pass a current through needles themselves corrode in time and to facilitate their replacement it has been proposed in GB-A-2,278,986 to mount the electrodes on a cartridge type electrode plate unit having syringe insertion holes. This facilitates the task of clearing debris from the vicinity of the electrodes, which will themselves be contaminated with pathogens, but the scrap from the needles is stored in an open scrap box which still presents a hazard to the person emptying the disposal apparatus as it fills up with use, as the debris and the box are contaminated both from any drips from the syringe and from the aerosol action.

ObJect of the invention The present invention therefore seeks to provide an apparatus for the destruction of hypodermic needles in which removal from the apparatus of the debris resulting from the destruction of the needles may be carried out simply and safely.

Summary of the invention According to the present invention, there is provided an apparatus for disposing of hypodermic needles, comprising a main housing and a disposable closed cartridge releasably secured to the housing, the cartridge having an aperture for receiving needles, electrodes for applying a current to a hypodermic needle inserted into the aperture to destroy the needle and a compartment for storing debris resulting from the destruction of needles, and the housing having an electrical power supply for applying a voltage across the electrodes of the cartridge and means for causing movement of one of the electrodes in the cartridge to prevent a build-up of debris in the gap between the electrodes.

Because the destroyed electrodes in the present invention are contained in a closed disposable cartridge, there is no need for an operator to do any more than detach the cartridge from the housing and fit a new cartridge as soon as the cartridge becomes full of debris from destroyed hypodermic needles.

The invention differs from the disposal apparatus described in GB-A-2,278,986 not only on account of the ease and safety with which debris may be emptied but because of the fact that accumulation of debris on the electrodes is avoided by causing one of the electrodes to be moved. By contrast, in GB-A-2,278,987, accumulation of debris on the electrodes is avoided by the use of expensive electrodes that are faced with chips of high quality carbon.

One of the electrodes may be a drum or a disc rotatably mounted on a shaft in the cartridge, in which case a drive spindle may be provided on the housing to engage with the shaft on which the electrode is mounted through a releasable coupling.

It is however preferred to avoid build-up of debris by vibrating one of the electrodes rather than rotating it. In this case, a solenoid may be mounted in the housing to apply a force to the electrode either by way of a transmission member passing through a wall of the cartridge or directly through a suitably weakened section of the wall of the cartridge or a flexible diaphragm mounted in the wall.

Brief description of the drawings The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is perspective view showing a disposable cartridge in the process of being fitted to a housing, Figure 2 is block diagram of the elements contained within the housing in Figure 1, and Figure 3 shows a section through the housing with the cartridge mounted in the operating condition.

Detailed description of the preferred embodiment Figure 1 shows an apparatus for disposing of hypodermic needles comprising a housing 10 and a replaceable cartridge 12. The cartridge 12 and the housing 10 having mating surfaces that are designed to interlock with one another.

For example, the cartridge 12 may have two projecting dovetails slidably received in matching grooves in the housing 10. When the cartridge 12 is fully pushed down on the housing 10 two pads (not shown) on its underside make electrical contact with two pads 30, 32 that are provided on the upper surface of a small shelf 16 projecting from the housing 10.

The housing 10 contains a step-down transformer 18 connected to the mains supply through a circuit breaker 20. The transformer 18 has a first pair of output lines that supply an a.a voltage across the pads 30, 32 with which the cartridge comes into electrical contact. The transformer also supplies power to a circuit board 22 that drives a solenoid 24. The armature 26 of the solenoid 24 projects through a hole in the surface of the housing 10 that mates with the cartridge 12. The circuit board 22 is also connected to a pair of capacitance electrodes 36, 38 that detect when the cartridge is full.

As shown in Figure 3, the cartridge contains a pair of electrodes 40, 42 that are positioned beneath an aperture 44 in the cartridge through which the needle to be destroyed is introduced. The electrodes are connected through copper tracks on the inner surface of the cartridge 12 to the contact pads on the underside of the cartridge. The electrode 40 is mounted in the cartridge in such a manner that it may be vibrated by the armature 26 of solenoid 24, the electrode 40 having a pad 46 that is moved by the armature through a flexible grommet 48 that seals the cartridge 12. The other electrode 42 is mounted so that it may pivot about its mounting rivet 50 and close the gap between it and the vibratable electrode 40.

In operation, a manual ON/OFF button 52 on the housing 10 is depressed to supply an a.c. voltage to the primary winding of the transformer 18 through the circuit breaker 20. A light 54 comes on to indicate that the apparatus is in use and an a.c. voltage is applied across the electrodes 40, 42 in the cartridge 12 by way of the contacts 30, 32. When a needle is introduced through the aperture 44 into the cartridge 12, it makes contact with both electrodes 40 and 42 and the high current that flows through its tip causes the tip to melt. At the same time, the electrode 40 is vibrated by the solenoid 24, the armature 26 of which acts on the electrode 40 through the grommet 48 in the wall of the cartridge 12. The vibration of the electrode 40 prevents debris from the incineration of the needle from adhering to it and creating d short circuit across the electrodes 40, 42.

The destruction of the needle takes place at a steady rate as it is lowered into the cartridge 12 and when it has been burned down to its collar, the latter causes the electrode 42 to pivot about its mounting rivet in order to reduce the gap between the electrodes and burn the last remains of the needle. The temperature that melts the needle is also high enough to incinerate any toxic residue on the needle so that danger of contamination is minimised.

The debris that builds up in the cartridge 12 is electrically conductive and when it reaches a certain level, its presence is detected by the fact that it alters the capacitance between the electrodes 36 and 38 connected to the circuit board 22. The board 22 carries a circuit that responds to this change in capacitance and energises an indicator light 56 positioned near the ON/OFF button 52 to warn the operator that the cartridge 12 is due for replacement. The cartridge 12 is then simply removed from the housing 10 and replaced by a new cartridge. There is no need to come into contact with the debris when replacing the cartridge. Furthermore, because the electrodes are renewed when a new cartridge is fitted, the apparatus has no parts that require regular attention or servicing.

The cartridge 12 is formed in two halves that are assembled to one another to make a permanently sealed assembly. The cartridge cannot be opened and the aperture 44 through which the needle is introduced into the cartridge can be closed by a rubber bellows so that the interior of the cartridge may remain sealed at all times.

Various modifications may be made to the apparatus described above without departing from the scope of the invention as set forth in the appended claims. For example, the movable electrode could be a disc or a drum roLated--by a motor mounted in place of the described solenoid and connected to the motor through a releasable coupling.

When using a vibratable electrode, the means for vibrating it may be a piezoelectric crystal rather than a solenoid and this crystal may be positioned either in the main housing or in the cartridge. The advantage of placing the crystal in the cartridge is that only electrical connections would then be needed between the cartridge and the main housing. The crystal would also be replaced with each new cartridge leaving fewer components in the housing to require servicing or repair.

If a vibration is to be transmitted through the wall of the cartridge, in place of a hole sealed my a grommet, the cartridge could be formed with an integral vibratable diaphragm surrounded by a weakened wall region.

In a further possible modification of the illustrated embodiment, one may, for ease of use, arrange for the presence of a needle to be detected and to switch on the power to the electrodes 40, 42 and to the solenoid 24 automatically when a needle is inserted into the cartridge 12 for disposal.

Claims

1. An apparatus for disposing of hypodermic needles, comprising a main housing and a disposable closed cartridge releasably secured to the housing, the cartridge having an aperture for receiving needles, electrodes for applying a current to a hypodermic needle inserted into the aperture to destroy the needle and a compartment for storing debris resulting from the destruction of needles, and the housing having an electrical power supply for applying a voltage across the electrodes of the cartridge and means for causing movement of one of the electrodes in the cartridge to prevent a build-up of debris in the gap between the electrodes.

2. An apparatus as claimed in claim 1, wherein one of the electrodes is mounted in the cartridge in such a manner that it may be vibrated, and wherein the housing comprises a solenoid having an armature acting on the vibratable electrode.

3. An apparatus as claimed in claim 2, wherein the armature of the solenoid passes through a hole in the housing and acts on the vibratable electrode through a flexible grommet in the wall of the cartridge.

4. An apparatus as claimed in any preceding claim, wherein the other electrode is mounted for pivotal movement in the cartridge towards and away from said one electrode in order to reduce the gap between the electrodes.

5. An apparatus for disposing of hypodermic needles, constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.