Utensil steriliser

Abstract

Utensil steriliser comprising a frame 1; disinfectant vessel 2 comprising a fluid outlet 23; sterilisation vessel 3 housing an ultrasonic transducer 44; wherein the disinfectant vessel and the sterili

Description

Technical Field The present invention relates to a utensil steriliser and a method for sterilising utensils using such a utensil steriliser. Background In remote regions, conflict zones, or in the aftermath of natural disasters, there is often an acute need for sterile medical equipment which is difficult to meet, in part, due to a lack of functioning sterilisation equipment. Much of the sterilisation equipment used in hospitals and clinics in cities requires mains electricity and a stable operating surface, or in the case of chemical disinfection, requires appropriate quantities of chemical disinfectant, and can give rise to large quantities of hazardous waste. CN111036612A provides a cleaning, disinfecting and sterilizing device for immersed type medical equipment. The cleaning, disinfecting and sterilizing device for medical equipment comprises a reaction slot, an ultrasonic generator, a circulating pump mechanism, an oxidizing reaction mechanism, a chemical agent supply mechanism and a drying mechanism. The use of a circulating pump requires a power input which may be unreliable in the scenarios outlined in the previous paragraph. US2013152982A1 provides a medical device cleaning device which includes a washing tank fed by a pump, and an electrical discharge generator. An endoscope to be cleaned is housed in the washing tank and immersed in wash water. An electrical discharge unit of the electrical discharge generator is placed in the washing tank and immersed in the wash water. A direct-current power supply is connected to a pair of electrodes of the electrical discharge unit. When the direct-current power supply applies a voltage to the pair of electrodes, streamer discharge is performed between the pair of electrodes to produce hydrogen peroxide. The endoscope is sterilized in the washing tank by using the hydrogen peroxide produced by the streamer discharge. Summary The present invention provides a utensil steriliser according to claim 1. This provides a sanitizer which is able to combine a disinfectant with ultrasonic cleansing to provide a powerful sterilisation process. By providing a frame to which the two vessels are mounted, the unit can be readily portable. Further the fact that the disinfectant vessel can be mounted to the frame above the sterilisation vessel, allows a gravity feed to the disinfectant thereby eliminating the need for a pump. Reducing the power requirement provides a unit which can more easily be run from a portable power supply such as a generator or battery. It is therefore more suited to remote locations where mains power may not be available. The vessels may be mountable on the frame in a single configuration. However, the utensil steriliser is preferably configurable between a storage configuration and an operational configuration in which the disinfectant vessel is above the sterilisation vessel. This allows the steriliser to be transported in the storage configuration in which it can be more compact and then reconfigured to the operational configuration in situ. The vessels may be mounted one above the other in the storage configuration and be laterally movable to the operational configuration. However, preferably they are mounted side by side and the disinfectant vessel is raisable to the operational configuration. In this case, the frame preferably has a rail system for raising the disinfectant vessel to the operational configuration. The disinfectant vessel is preferably raisable manually. This avoids the need for a powered lifting mechanism, thereby simplifying the steriliser and reducing its power requirement. The disinfectant vessel may be filled with a disinfectant which is produced externally. However, preferably the disinfectant vessel comprises electrodes for the production of disinfectants by electrolysis. This allows the disinfectant to be produced in situ which provides benefits in terms of avoiding the transportation of bulk / hazardous materials, particularly when a significant component of the disinfectant is water. This is particularly effective when the disinfectant is hypochlorous acid (HOCI). The steriliser preferably further comprises a valve for controlling fluid flow between the disinfectant vessel and the sterilisation vessel. This allows control of the flow into the sterilisation vessel. The sterilisation vessel may be emptied after use by tipping out the disinfectant. However, preferably the sterilisation vessel comprises an outlet to allow a controlled flow. The outlet may be in the bottom of the sterilisation vessel but is preferably above the lower liquid level in the sterilisation vessel. This allows the outlet to be at the liquid surface to create a weir like outlet which is effective in discharging floating debris. Preferably the outlet has a funnel like configuration with an open wider top leading to a narrower downwardly extending outlet duct. This provides a greater area for the flow of floating debris. Preferably an upper rim of the outlet is provided with a plurality of notches or castellations. The notches or gaps between castellations provide localised regions of higher flow to encourage the outflow of the floating debris The outlet duct is preferably retained and sealed in an opening in the sterilisation vessel. This anchors it in place effectively. The steriliser preferably further comprises an inlet duct into the sterilisation vessel connected to the fluid outlet of the disinfectant vessel. The inlet duct can be configured to optimise the flow conditions in the sterilisation vessel. For example, preferably the inlet duct is configured to provide a distributed inlet flow into the sterilisation vessel. The inlet duct and outlet are preferably at opposite ends of the sterilisation vessel. This promotes a flow towards the outlet and helps flush the floating debris towards the outlet. The inlet may be in the bottom of the sterilisation vessel. This generates an upward flow in the vessel towards the outlet. Preferably the inlet duct is above the lower liquid level in the sterilisation vessel. This favours a flow across the vessel rather than from bottom to top which may be more effective if the debris is naturally buoyant. This lateral flow is optimised if the inlet duct is at substantially the same height as the outlet. The disinfectant vessel preferably has a larger capacity than the sterilisation vessel. This allows a continuous flow operation in which the sterilisation vessel is first filled and then the disinfectant vessel provides a continuous flow to the sterilisation vessel as the ultrasonic transducer is operated to provide a flow which flushes out the debris. Preferably the steriliser further comprises a user interface for the setting or controlling of any of: electrode voltage, electrolysis duration, temperature and / or sonication duration. The invention preferably extends to a method of claim 21. Preferably the method further comprises filling the disinfectant vessel with reagents for producing hypochlorous acid; and supplying power to the electrodes in the disinfectant vessel to create the hypochlorous acid. Preferably the method further comprises maintaining a flow of disinfectant through the sterilisation vessel while operating the ultrasonic transducer. Brief Description of the Drawings Fig. 1 is a side view of the utensil sterilizer in an operational configuration; Figs. 2-4 are views similar to Fig. 1 showing various stages of operation of the sterilizer; Fig. 5 is a schematic cross-section through the sterilisation vessel and surrounding frame; Figs. 6A - 6E are perspective views of various alternative sterilisation vessel inlet configurations; Figs. 7A, 7B, 7D, 7E, 7F and 7H are perspective views of various alternative sterilisation vessel outlet configurations; Figs. 7C and 7G show details of Figs. 7B and 7F respectively; Fig. 7I is a perspective view of a further sterilisation vessel outlet; Fig. 7J is a top view of the outlet of Fig. 7I Fig. 8 is a perspective view of the steriliser is a crate for transportation; Figs 9A to 9C are perspective views showing various stages in the set up process; and Fig 10 is a perspective view showing part of a roller / rail mechanism The utensil steriliser consists of a number of basic modules in the form of the frame 1, disinfectant vessel 2, sterilisation vessel 3 and control module 4. The frame 1 is assembled from a plurality of rails 10 to form a disinfectant vessel section 11 at a central portion of the frame, a sterilisation vessel section 12 to the right-hand side of the frame and a control module section 13 on the left-hand side of the frame. The frame need not be in this configuration. For example, the control module section 13 is optional as control could be done from a separate location. Alternatively the control module section 13 could be in front of or behind the disinfectant vessel section 11 or the sterilisation vessel 12, or could be to the right of these sections in the Figures. As can be seen in Figs. 1-4, the disinfectant vessel section 11 extends higher than the sterilisation vessel section 12. The utensil steriliser is delivered to the operational site in a crate C as shown in Fig, 8, with the disinfectant vessel 2 in its lowered position within the frame 1. The steriliser is removed from the crate 15 and placed on a flat surface as shown in Fig 9A. The crate C and frame 1 provide protection for the steriliser components in transit. The frame 1 incorporates a raisable platform section 14 in the disinfectant vessel section 11. This supports the disinfectant vessel 2 and is vertically slidable along the rails 10 of the disinfectant vessel section 11 on a roller system 15 (one part which is shown in Fig 10). The disinfectant vessel 2 is lifted by hand from a lower position (Fig 9B) in which the disinfectant vessel 2 is within the disinfectant vessel section 11 to a raised position in which the disinfectant vessel 2 is above the frame 1 as shown in Figs. 1 - 4 and 9C. Quick release latches (not shown) hold the platform 14 in the raised position. This provides a simple set up process in which all of the components are protected by the frae 1. The steriliser can effectively be fully assembled off site in a controlled setting with all of the appropriate electrical and fluid connections. Once in situ, the only assembly step is to raise the disinfectant vessel 2. This is a simple, robust and fool proof design. The disinfectant vessel 2 is a disinfectant tank 21 which can be filled with a pre-formed disinfectant. However, the intention is the disinfectant will be created in situ. In this case, the disinfectant tank 21 is provided with an_electrode system 24 to produce the disinfectant by electrolysis. Our intention is that the disinfectant vessel will operate using the principles of our Aquateck Mini. This is a way of producing hypochlorous acid (HOCI) from a combination of water, sodium chloride (salt) and acetic acid (vinegar) which are subject to electrolysis in the disinfectant tank 21. The sodium chloride may be replaced with other chloride salts appropriate for producing hypochlorous acid; hereinafter, salt refers to chloride salts. The acetic acid may be replaced with an alternative weak acid capable of forming a buffer in the same way as acetic acid. The current AquaTeck Mini, produces a solution at a pH of 6.5 which is approximately 93% HOCI, and 7% Sodium Hypochlorite. Adding more acid will reach a pH of 5.5, a result of 99.2% HOCI. Once in the operational configuration, the disinfectant vessel 2 is filled with salt solution and acetic acid solution which are dispensed from vessels and a measured quantity of water.. In some embodiments, the salt may be added in solid form (i.e. as tablets or as a powder) and mixed with the required quantities of water and acetic acid. Power is supplied to the electrode system 24 in order to electrolyse the liquid in order to create HOCI. Once this process is complete, the utensil steriliser is ready for use. In some embodiments, the relative quantities of salt, acetic acid, and water can be altered to achieve different concentrations of hypochlorous acid. In other embodiments, the same relative quantities of acetic acid and salt are added, and the concentration of hypochlorous acid produced is controlled by the duration of electrolysis and / or the electrode voltage. The utensil steriliser may comprise a user interface for controlling the concentration of produced disinfectant. The user interface may comprise a selection of concentration options, for example 200, 500, and 1000 ppm concentrations of HOCI. These concentrations may correspond to known electrolysis durations and / or electrode voltages. Alternatively, the user interface may comprise controls for electrode voltage and / or electrolysis duration directly, and the user of the utensil steriliser may assess the concentration of the produced solution by other means, such as indicator strips. The sterilisation vessel comprises a sterilisation tank 41 with an inlet 42 at one end and an outlet 43 at the opposite end. A piezoelectric element 44 is provided in the base to generate ultrasonic waves in the liquid in the sterilisation tank 41. The sound waves may have a frequency from 15 kHz to 60 kHz, and preferably 20 - 40 kHz. The user interface may further comprise a setting for controlling the duration of sonication. In the first stage in the disinfecting operation, a valve on the disinfectant vessel outlet 23 is opened to fill the sterilisation tank 41 with disinfectant. Once the sterilisation tank 41 is full of disinfectant, the objects to be cleaned are placed into the sterilisation tank 41 and the piezoelectric transducer 44 is operated. A combination of disinfectant and the ultrasound causes the components to be cleaned, and the debris dislodged rises to the surface of the liquid in the sterilisation tank 41 and is drained through the outlet 43. The sterilisation vessel may comprise a heating element as these are often fitted in ultrasonic tanks. However when using HOCI, the heater is not used as HOCI is more effective when cold.,. The sterilisation vessel may comprise a separate user interface (i.e. distinct from that for the disinfection vessel), or the controls for the sterilisation vessel and disinfection vessel may be incorporated into a single interface. In some embodiments, to reduce the power requirement, there may be no heating element in the sterilisation vessel. The amount of disinfectant generated is preferably larger than the capacity of the sterilisation tank 41 so that a continuous flow of disinfectant is maintained during the ultrasonic cleaning to encourage the debris to flow to the outlet 43. The sterilisation vessel 41 may be sufficiently filled with a first batch of disinfectant such that disinfection and sonication can take place. The disinfectant vessel 2 may then be filled again either with reagents for forming a second batch of disinfectant in situ, or with a second batch of disinfectant. If filled with the former, electrolysis may occur to produce a second batch disinfectant in situ. The utensil to be sterilised may be placed in the sterilisation vessel (sufficiently filled with the first batch of disinfectant), and the second batch of disinfectant may be allowed to create a flow through the sterilisation vessel during the ultrasonic cleaning process. Various designs of inlet 42 and outlet 43 will now be described. Figs. 6A-6E show various inlet configurations. Fig. 6A shows an inlet duct 42A which extends downwardly then laterally across the sterilisation tank 41. Only the lower part of the inlet duct 42A is provided with outlet orifices 53 which produces an inlet flow distributed along the length sterilisation tank 41. This is directed upwardly depicted by the arrows 54. The resultant flow direction is shown by arrow 55. This upward flow direction assists in flushing the debris within the tank as it helps it rise to the surface of the liquid within the sterilisation tank 41. A refinement of this configuration is shown in Figure 6B. This is essentially the same previously described example except that the inlet conduit 42B is also provided with lateral orifices 53B in the vertical part of the conduit. The resultant flow direction is both upwards and from left to right thereby creating a flow which will lift the debris in the sterilisation tank 41 as well as pushing it towards the end of the outlet end of sterilisation tank 41. Fig. 6C is similar to Fig. 6B, except that the lateral portion of the conduit 42C is bifurcated to provide two upwardly directed flows. This distributes the flow more evenly across the width of the tank. This design deters debris from accumulating at the sides of the sterilisation tank in use through reducing regions of low flow velocity which may occur at the edge of the sterilisation tank 41 in other designs. Fig. 6D shows a different approach in which an inlet conduit 42D with a lateral line of orifices 53D is positioned at the upper level of the liquid within the sterilisation tank 41. This creates a distributed flow between the inlet and the outlet ends of the sterilisation tank 41 but does not create an upward flow. This arrangement is suitable for a situation where the debris is expected to be buoyant, such that the inlet flow energy is better used in pushing the debris horizontally towards the outlet. Fig. 6E is another surface mounted inlet conduit 42E. This has two outlets 53E. As with Fig. 6D, this generates a lateral flow within the tank, and as with Figure 6C, this design deters debris from accumulating at the sides of the sterilisation tank 41 in use through reducing the occurrence of regions of low flow velocity at the edge of the sterilisation tank 41. A number of outlet configurations are shown in Figs. 7A-7J as described below. As a general point, the outlet 43 consists of an outlet opening 65 positioned at the upper level of the liquid within the sterilisation tank 41. This leads to an outlet duct 66 which extends down through the bottom wall of the sterilisation tank 41 and leads to an outlet port 67 via which the sterilisation tank can be drained. The outlet duct 66 may be removably attachable to the outlet port 67 at outlet connection. The bottom surface of the sterilisation tank 41 may be sloped towards the outlet port 67, such that removal of the outlet duct 66 from the outlet port 46 empties the sterilisation tank 41. The outlet duct 66 has a collar 68 which abuts against the base of the sterilisation tank 41 to ensure that the outlet opening 65 is at the correct height. A bung (not shown) may be provided beneath the collar 68 to ensure that the outlet duct 66 is tightly wedged in place and does not tend to float up. This can alternatively be anchored in other ways. Various examples of outlet configurations will now be described. Fig. 7A has an elongate opening 65A extending laterally across the sterilisation tank 41. This effectively provides a weir over which the water and debris will flow as depicted by arrows 68. Fig. 7B is similar to Fig. 7A but has castellations 70 around the opening 65B as shown in detail in Fig. 7C. These promote the flow of debris to the outlet. Fig. 7D is similar to Fig. 7B, except that the outlet duct 66 is now placed centrally of the inlet opening 65D and the castellations 70 are only provided at the side of the outlet opening 65D which faces the main flow direction. This can be installed against a wall of the tank at the outlet end. Fig. 7E shows a large circular outlet opening 65E effectively forming a funnel. Figs 7F and 7G are similar, except that an outwardly curved lip 71 is formed at the outer edge of the outlet opening 65F in order to promote debris flow. Fig. 7H is similar to Fig. 7E, but the outlet opening 44H is provided with notches 51 operating the same way as the castellations 49 from the earlier examples in order to promote debris flow. The final example is shown in Figs. 7I and 7J. The outlet opening 65I is generally a semicircular shape, although as is apparent from Fig. 7J the shape is slightly wider than a true semi-circle. A flat side 72 can be mounted against the sidewall of the sterilisation tank 41 while a front curved face 73 faces the oncoming flow and is provided with castellations 70 as previously described. The outlet duct 66 or outlet opening 65 may comprise a straining or sieving element (not shown) to trap debris above a certain size. This may be situated immediately upstream of the outlet duct 66 or at the upstream end of the outlet duct 66. The straining or sieving element may be for trapping debris above the certain size. The certain size may be chosen so as to minimise the chance of the outlet duct 66 or outlet port 67 from becoming blocked by large debris elements, to ensure continuous drainage during operation of the utensil steriliser. The utensil steriliser may be battery-powered or provided by a dynamo or comprise a battery which is chargeable with a dynamo. Alternatively, the steriliser may be solar powered and this may be combined with a battery. This is advantageous for operation of the device in remote regions, or regions in which the power supply may be intermittent, unreliable, or non-existent.

Claims

1. A utensil steriliser comprising:a frame;a disinfectant vessel comprising a fluid outlet;a sterilisation vessel housing an ultrasonic transducer;wherein the disinfectant vessel and the sterilisation vessel are mountable to the frame with the disinfectant vessel above the sterilisation vessel, such that the fluid outlet forms a gravity fed flow path from the disinfectant vessel to the sterilisation vessel.

2. The utensil steriliser of claim 1, wherein the utensil steriliser is configurable between a storage configuration and an operational configuration in which the disinfectant vessel is above the sterilisation vessel.

3. The steriliser of claim 2, wherein the utensil steriliser is configurable by hand.

4. The utensil steriliser of claim 2 or claim 3, wherein the disinfectant vessel and sterilisation vessel are mounted side by side and the disinfectant vessel is raisable to the operational configuration.

5. The utensil steriliser of claim 4 wherein frame has a rail system for raising the disinfectant vessel to the operational configuration.

6. The utensil steriliser of any preceding claim wherein the disinfectant vessel comprises electrodes for the production of disinfectants by electrolysis.

7. The utensil steriliser of claim 6, wherein the disinfectant is hypochlorous acid.

8. The utensil steriliser of any preceding claim further comprising a valve for controllingfluid flow between the disinfectant vessel and the sterilisation vessel.

9. The utensil steriliser of any preceding claim, wherein the sterilisation vessel comprises an outlet.

10. The utensil steriliser of claim 9 wherein the outlet is above the lower liquid level in the sterilisation vessel.

11. The utensil steriliser of any of claims 10, wherein the outlet has a funnel like configuration with an open wider top learning to a narrower downwardly extending outlet duct.

12. The utensil steriliser of claim 10 or 11, wherein an upper rim of the outlet is provided with a plurality of notches or castellations.

13. The utensil steriliser of any of claims 10 to 12, wherein the outlet duct is retained and sealed in an opening in the sterilisation vessel.

14. The utensil steriliser of any preceding claim, further comprising an inlet duct into the sterilisation vessel connected to the fluid outlet of the disinfectant vessel.

15. The utensil steriliser of claim 14, wherein the inlet duct is configured to provide a distributed inlet flow into the sterilisation vessel.

16. The utensil steriliser of any of claims 14 or 15 wherein the inlet duct and outlet are at opposite ends of the sterilisation vessel.

17. The utensil steriliser of any of claims 14 to 16, wherein the inlet duct is above the lower liquid level in the sterilisation vessel.

18. The utensil steriliser of claims 10 and 17, wherein the inlet duct is at substantially the same height as the outlet.

19. The utensil steriliser of any preceding claim, wherein the disinfectant vessel has a larger capacity than the sterilisation vessel.

20. The utensil steriliser of any preceding claim, further comprising a user interface for the setting or controlling of any of: electrode voltage, temperature and / or sonication duration.

21. A method of sterilising a utensil with a utensil steriliser according to any preceding claim comprising:placing the disinfectant vessel on the frame at a level above the to the5 sterilisation vessel;allowing disinfectant to flow under gravity from the disinfectant vessel into the sterilisation vessel; andoperating the ultrasonic transducer to sonicate the utensil in the disinfectant in the sterilisation vessel.

022. The method of claim 21 when the utensil steriliser is dependent upon claims 6 and 7, further comprising filling the disinfectant vessel with reagents for producing hypochlorous acid; and supplying power to the electrodes in the disinfectant vessel to create the hypochlorous acid.

523. The method of claim 21 or 22 further comprising maintaining a flow of disinfectant through the sterilisation vessel while operating the ultrasonic transducer.s

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