A medical washer-disinfector method for reducing air entrainment in a circulation pump of a medical washer-disinfector

Abstract

A medical washer-disinfector comprises a washing chamber configured to receive medical articles to be washed and / or disinfected. A recirculation conduit extends from the chamber outlet at a bottom wall of the washing chamber to one or more chamber inlets. A circulation pump cause water to be removed from the washing chamber and then recirculated in the recirculation conduit to the washing chamber through said one or more chamber inlets. A filter is provided in the chamber outlet. A filter cover is provided in a lower part of the washing chamber, the filter cover being located above and vertically spaced from the filter such that a separation volume is present between the filter cover and the filter. The filter cover causes water, drawn by the circulation pump and moving from above the filter cover, to be deflected by the filter cover before reaching the separation volume and then passing through the filter.

Description

[0001] P482111PC00

[0002] 1

[0003] A medical washer-disinfector method for reducing air entrainment in a circulation pump of a medical washer-disinfector

[0004] TECHNICAL FIELD

[0005] The present disclosure relates to a medical washer-disinfector, comprising a washing chamber configured to receive medical articles to be washed and / or disinfected. The present disclosure also relates to a method for reducing air entrainment in a circulation pump of a medical washer-disinfector.

[0006] BACKGROUND ART

[0007] Medical washer-disinfectors may typically be provided at dental clinics, surgical departments, central sterile supply departments, and similar facilities. The medical washer-disinfectors may be used for washing and / or disinfecting a wide range of different medical articles, such as recirculated goods, tubular instruments, surgical sets, anaesthetic items, laboratory items, bedpans, etc. In other words, a medical washer-disinfector should be able to handle a large variety of different type of goods, which means that sometimes a smaller load size will be processed, and at other occasions a larger load size will be processed. Medical washerdisinfectors are commonly intended to provide both cleaning of visible physical contaminants from medical devices or medical equipment, as well as a degree of disinfection, such as by hot water exposure and / or cleaning / disinfection agents.

[0008] A medical washer-disinfector usually has a washing chamber in which medical articles can be washed and / or disinfected. The water present in the washing chamber may, in at least some medical washer-disinfectors, after discharging the water, be recirculated back into the washing chamber. From an environmental perspective, it is desirable not to use too much water. To be able to lower the water volume in a circulation system of the medical washer-disinfector, the circulation pressure needs to be maintained at a sufficient level to achieve desired cleaning result. When the water level in the washing chamber during a process is too low, the circulation pump will have too much air entrainment and may start losing pressure. To reduce the risk of such air entrainment, it is of course possible to increase the water level in the washing chamber, as this will make bubbles collect and bubble back to the water surface when the lift force in the bubbles is greater than the downwards pulling force of the water stream (caused by the circulation pump). However, this counteracts the previously mentionedenvironmental perspective and the desire to keep a low usage of water. Thus, there is still room for improvement.

[0009] SUMMARY OF THE INVENTION

[0010] An object of the present disclosure is to provide a medical washer-disinfector which at least partly alleviate the drawbacks of the prior art.

[0011] The general inventive concept is based on the realization that the amount of mixing between air and water can be reduced by providing an appropriate physical obstruction for the air, such that clearer water (i.e. lower air content) can enter the circulation pump, thus reducing the risk of losing pressure at relatively low water levels.

[0012] According to a first aspect of the present disclosure, there is provided a medical washerdisinfector, comprising:

[0013] - a washing chamber configured to receive medical articles to be washed and / or disinfected, the washing chamber being at least partly defined by side walls and a bottom wall, wherein the washing chamber has a chamber outlet and one or more chamber inlets, wherein the chamber outlet is provided at the bottom wall and configured to allow water to be removed from the washing chamber through the chamber outlet,

[0014] - a recirculation conduit extending from the chamber outlet to said one or more chamber inlets, - a circulation pump provided in the recirculation conduit and configured to, by means of its pumping action, cause water to be removed from the washing chamber and then recirculated in the recirculation conduit to the washing chamber through said one or more chamber inlets, - a filter provided in the chamber outlet, and

[0015] - a filter cover provided in a lower part of the washing chamber, the filter cover being located above and vertically spaced from the filter such that a separation volume is present between the filter cover and the filter, wherein the filter cover causes water in the washing chamber, drawn by the pumping action of the circulation pump and moving from above the filter cover, to be deflected by the filter cover before reaching the separation volume below the filter cover and then passing through the filter.

[0016] By deflecting the water before reaching said separation volume, the amount of air that mixes with water is reduced. Due to the deflection of the water flow, air bubbles are allowed to escape from the stream caused by the circulation pump and bubble upwards to the water surface. In contrast, a traditional substantially vertical flow creates a high amount of air mixing. As mentioned above, the filter cover is located vertically above the filter. Thus, the understanding of terms such as vertical, horizontal, up, down, above, below, etc. should beclear enough. For example, the water is drawn generally downwardly by the circulation pump, although it is temporarily deflected by the filter cover. Initially, if water has been supplied into the washing chamber, and you allow the water to come to a standstill before starting he circulation pump, then the water surface will extend horizontally.

[0017] According to at least one exemplary embodiment, the filter cover may have a lower side facing the filter and an opposite upper side facing away from the filter, the medical-washer disinfector further comprising:

[0018] - a support, such as comprising one or more brackets, which projects from one of the walls defining the washing chamber or from a connecting element attached to one of the walls defining the washing chamber, wherein the support is located vertically spaced from the filter and configured to receive and support the lower side of the filter cover.

[0019] This is advantageous because it allows the filter cover to be lowered onto the support, suitably just held in position by its own weight. When desired to clean the filter, the filter cover can simply be lifted and removed from the support.

[0020] There may suitably be more than one support. For instance, there may be a first support projecting from a first one of the walls (such as a first side wall) defining the washing chamber and a second support projecting from a second one of the walls (such as a second side wall) defining the washing chamber. The first one of the walls and the second one of the walls may suitably be arranged opposite to and facing each other.

[0021] According to at least one exemplary embodiment, the filter may have an outer perimeter defining the lateral (or horizontal) extension of the filter, wherein lateral extension is transverse to vertical extension, wherein the filter cover has a larger lateral extension compared to the lateral extension of the filter, such that the filter cover extends laterally beyond the outer perimeter of the filter.

[0022] Hereby, there can be no water stream that flows vertically straight into the filter without first being deflected by the filter cover. Thus, by avoiding a long straight vertical stream into the filter, entrained air bubbles in the stream will, upon said deflection, get a chance to leave the stream before reaching the filter and then the circulation pump. Hereby, the risk of too much air mixed with water reaching the circulation pump may be avoided even better.

[0023] According to at least one exemplary embodiment, water moving downwardly from above the filter cover may be:

[0024] - first laterally deflected by the filter cover,

[0025] - then vertically passed along the filter cover,

[0026] - then laterally returned below the filter cover to the separation volume between the filter cover and the filter, and- then passed through the filter.

[0027] Similarly to what has been discussed above, causing the water to change direction allows bubbles entrained in the stream to escape the stream and rise towards the water surface. The back-and-forth path of the stream will allow more opportunities for the bubbles to escape. According to at least one exemplary embodiment, a gap may be present between the filter cover and the bottom wall.

[0028] Such a gap may suitably provide access for the water stream to the separation volume and then to the filter. Thus, in at least some exemplary embodiments, the separation volume may be partly defined by a portion of the bottom wall, i.e. in addition to being defined by the filter and the filter cover. A small gap may be enough to keep the water flowing to the circulation pump, while counteracting most of the air following the water to the circulation pump. As a purely illustrative example, the distance between the filter cover and the bottom wall may, for example, be in the range of 10-15 mm.

[0029] According to at least one exemplary embodiment, said gap may be a first gap, wherein a second gap may be present between the filter cover and at least one of the side walls. Such a second gap may suitably be located at a vertically higher level than the first gap. Furthermore, such a second gap may suitably function as an exit passage for air bubbles that have escaped from the stream when in the separation volume. Air bubbles that escape from the stream in the separation volume may rise through the separation volume until they reach the filter cover. By having a second gap, those air bubbles may then be allowed to continue to rise after exiting the second gap between the filter cover and the side wall. Thus, according to at least one exemplary embodiment, the second gap may be located at a higher vertical location than the first gap, and wherein the second gap may be configured to allow air bubbles to escape from the separation volume into the washing chamber.

[0030] From the above it can be understood that to effectively separate air from the recirculating water, the filter cover may rely on a dual-elevation gap configuration. A first gap may be provided at a lower vertical location, for example between the filter cover and the bottom wall, to allow the deflected water stream to enter the separation volume. Furthermore, the filter cover may comprise at least one second gap or aperture located at a higher vertical location than the first gap. Because air bubbles naturally rise within the separation volume due to buoyancy, they accumulate near the underside of the filter cover. The at least one second gap or aperture may act as a dedicated venting route, allowing these trapped air bubbles to escape from the separation volume and rise freely back into the washing chamber. By structurally isolating the fluid entry point (the lower first gap) from the air escape point (the higher second gap or aperture), the filter cover can counteract the downward pulling force of the pump fromdragging the separated air bubbles back into the filter.

[0031] According to at least one exemplary embodiment, the bottom wall may taper downwardly from the side walls towards the chamber outlet, wherein a horizontal geometrical plane cuts the filter cover and the tapering bottom wall.

[0032] Thus, the bottom wall may suitably function as a funnel-like part which directs and / or converges the water towards the filter. The filter cover may thus be located at the same vertical level as at least a portion of the bottom wall. In other words, the filter cover and the tapering bottom wall may extend across / through a common horizontal geometrical plane.

[0033] According to at least one exemplary embodiment, the filter cover has at least one inclined portion which extends oblique with respect to horizontal and vertical geometrical planes. A technical benefit of having an inclined filter cover is that it counteracts water and dirt accumulating on the filter cover. Thus, in at least some exemplary embodiments the filter cover does not extend as a horizontally planar cover. In some examples the filter cover may have one inclined portion, whereas in other examples the filter cover may have two or more inclined portions. For instance, the filter cover may be formed substantially as a house roof with two sides extending from an apex. This is at least partly reflected in the following exemplary embodiment.

[0034] According to at least one exemplary embodiment, the filter cover has a central apex from which the at least one inclined portion extend downwardly.

[0035] As mentioned above, this could be shaped similarly to a house roof having two sides extending from the central apex. In other examples, it could be a conical shape extending from a central pointed apex. In either case, accumulation of dirt can be avoided. Also, any amount of water remaining water on the filter cover after discharging water from the washing chamber before a drying process, may be reduced.

[0036] According to at least one exemplary embodiment, the apex is elongated and has two opposite ends, wherein air bubbles rising vertically in the separation volume and reaching the apex are allowed to escape from the filter cover via at least one of the ends of the apex so as to continue to rise in the washing chamber.

[0037] Similarly, to what has been discussed above with respect to the second gap, this allows air bubbles that have been entrained by the water stream and that have bypassed the filter cover but then escaped in the separation volume, to leave the separation volume at the ends of the apex. Thus, at least one of the ends of the apex (suitably both ends) is laterally spaced from a wall, such as a side wall, to form a gap, such as the previously mentioned second gap.According to at least one exemplary embodiment, the lower side of the filter cover may define an inverted funnel configured to guide separated air bubbles rising within the separation volume upwardly along the at least one inclined portion toward the central apex, and longitudinally along the central apex toward said at least one second gap or aperture. Hereby, an efficient separation of air bubbles is achieved with reduced risk of them being reentrained in the downwards water flow.

[0038] According to at least one exemplary embodiment, the filter cover may deflect water moving downwardly from above the filter cover in at least two lateral directions, and wherein the water then reaches the separation volume from at least two lateral directions.

[0039] Similarly to previously discussed examples, the change of directions enable air bubbles to escape from the water stream, thus further reducing the risk of to much air being mixed with the water that reaches the circulation pump.

[0040] According to at least one exemplary embodiment, the washing chamber may be configured and dimensioned to receive a wash cart, and wherein a manifold of the wash cart may be connectable to flow passages of the medical washer-disinfector to function as at least one of said chamber inlets. Thus, unlike consumer-grade washing appliances designed for single items or simple dishware, the medical washer-disinfector may be specifically engineered for high-capacity, stringent cleaning and thermal disinfection of medical instruments. To accommodate large and varied loads, the washing chamber may therefore suitably be configured and dimensioned to receive a removable wash cart. When the wash cart is rolled into the washing chamber and docked into an operating position, a manifold of the wash cart may be configured to physically connect to internal flow passages of the medical washerdisinfector. In this docked configuration, the manifold of the wash cart functions directly as at least one of said chamber inlets, delivering high-pressure fluids which can be directed to the medical articles loaded on e.g. racks of the wash cart. This structural integration allows pressurized washing liquid to be distributed efficiently throughout a high-volume load, which is beneficial for medical-grade washing and / or disinfection processes.

[0041] In addition to the medical washer-disinfector of the first aspect, there is also provided a corresponding method of a second aspect. Technical benefits of the method of the second aspect are largely analogous to those of the first aspect, including any exemplary embodiments thereof.

[0042] Thus, according to a second aspect of this disclosure, there is provided a method for reducing air entrainment in a circulation pump of a medical washer-disinfector (such as the medical washer-disinfector of the first aspect, including any exemplary embodiment thereof). The method comprises:- operating a circulation pump to draw water downwardly from a washing chamber,

[0043] - deflecting the downwardly moving water laterally using a filter cover located above a filter, - guiding the deflected water to enter a separation volume located beneath the filter cover, - separating air bubbles from the water within the separation volume,

[0044] - allowing the separated air bubbles to escape upwardly from the separation volume and rise into the washing chamber; and

[0045] - passing the water with reduced air content through the filter to the circulation pump.

[0046] According to at least one exemplary embodiment, the act of deflecting the downwardly moving water laterally may comprise forcing the water to travel along a tortuous path by first flowing laterally outwards along the filter cover, then vertically downwards, and then laterally inwards below the filter cover to enter the separation volume.

[0047] According to at least one exemplary embodiment, allowing the separated air bubbles to escape upwardly may comprise guiding the rising air bubbles towards an elongated central apex of the filter cover and routing the air bubbles out of the separation volume via at least one open end of the elongated apex.

[0048] According to at least one exemplary embodiment, allowing the deflected water to enter the separation volume may comprise routing the water through a first gap defined between the filter cover and a bottom wall of the washing chamber, and wherein allowing the separated air bubbles to escape may comprise routing the air bubbles through a second gap or aperture located at a higher vertical level than the first gap.

[0049] According to at least one exemplary embodiment, the method may further comprise the act of introducing water into the washing chamber through a manifold of a wash cart that is docked within the washing chamber.

[0050] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present inventive concept may be combined to create embodiments other than those described in the following, without departing from the scope of the present inventive concept.BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Fig. 1 illustrates schematically, in a cross-sectional view, a medical washer-disinfector according to at least one example of this disclosure.

[0052] Fig. 2 is an enlarged view of a portion of Fig. 1.

[0053] Fig. 3 is a schematic illustration, in a side view, of a filter cover according to at least one example of this disclosure.

[0054] Fig. 4 is a schematic illustration, in a perspective view, of a filter cover according to at least one example of this disclosure.

[0055] DETAILED DESCRIPTION

[0056] The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the inventive concept are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, the embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Accordingly, it is to be understood that the present inventive concept is not limited to the embodiments described herein and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims. Like reference numerals refer to like elements throughout the description.

[0057] Fig. 1 illustrates schematically, in a cross-sectional view, a medical washer-disinfector 1 according to at least one example of this disclosure. The medical washer-disinfector 1 comprises a housing 2 inside of which there is provided a washing chamber 4. The washing chamber 4 is configured to receive medical articles to be washed and / or disinfected. The washing chamber 4 is at least partly defined by side walls 6 and a bottom wall 8. The side walls 6 and the bottom wall 8 may, in at least some examples, form part of the housing 2. In other examples, said walls 6, 8 may be internal walls within the housing 2.

[0058] The washing chamber 4 has a chamber outlet 10 and one or more chamber inlets 12. The chamber outlet 10 is provided at the bottom wall 8 and configured to allow water to beremoved from the washing chamber though the chamber outlet 10. In some examples, as illustrated in Fig. 1, there may be a chamber inlet 12 at the ceiling of the housing 2 (here illustrated as an inlet to a spray wing 14. However, other inlets may be located elsewhere, such as in nozzles in the side walls 6, etc. The washing chamber 4 may suitably be configured and dimensioned to receive a wash cart, in which case a manifold of the wash cart may be connected to flow passages of the medical-washer disinfector 1 and function as a chamber inlet.

[0059] A recirculation conduit 16 extends from the chamber outlet 10 to said one or more chamber inlets 12. A circulation pump 18 is provided in the recirculation conduit 16. The circulation pump 18 is configured to, by means of its pumping action, circulate water to and from the washing chamber 4. In particular, the circulation pump 18 is configured to cause water to be removed from the washing chamber 4 and then recirculated in the recirculation conduit 16 to the washing chamber 4 through said one or more chamber inlets 12.

[0060] With reference to both Figs. 1 and 2, a filter 20 is provided in the chamber outlet 10. The filter 20 is suitably arranged in such way that any (or at least a majority of) water flowing from the washing chamber 4 to the circulation pump 18 passes through the filter 20. The filter 20 may for example be provided in the form of one or more filtering screens.

[0061] A filter cover 22 is provided in a lower part of the washing chamber 4. More specifically, the filter cover 22 is located above and vertically spaced from the filter 20. As best seen in Fig. 2, a separation volume 24 is present between the filter cover 22 and the filter 20. Water that is present above the filter cover 22 in the washing chamber 4 is drawn by the pumping action of the circulation pump 18. The drawn water is deflected by the filter cover 22 before reaching the separation volume 24 below the filter cover 22 and then passing through the filter 20. Thus, the filter cover 22 causes the water to change direction before reaching the filter 20. Hereby, air bubbles will get a chance to escape from the stream caused by the circulation pump 18. Since the amount of air that mixes with water can be reduced in this way, water with lower air content will enter the circulation pump 18, thus reducing the risk of losing pressure at relatively low water levels.

[0062] With reference to Fig. 1 , the bottom wall 8 may suitably taper downwardly from the side walls 6 towards the chamber outlet 10. A horizontal geometrical plane P may be drawn which cuts the filter cover 22 and the tapering bottom wall 8. In other words, the filter cover 22 may suitably be at the same vertical level as the bottom wall 8. Thus, the filter cover 22 is suitably located well below any shelf, rack, tray etc for holding medical articles to be processed in the washing chamber.As can be seen in Fig. 2 the filter cover 22 may have a lower side 26 facing the filter 20 and an opposite upper side 28 facing away from the filter 20. One or more supports 30 may be provided for receiving and supporting the lower side 26 of the filter cover 22. For example, the one or more supports 30 may be in the form of one or more brackets 30. In Fig. 2 two brackets 30 have been illustrated, the filter cover 22 resting on both illustrated brackets 30. However, other number of brackets and other support configurations are conceivable. Each support 30 may suitably project from one of the walls defining the washing chamber 4, or from a connecting element 32 attached to one of the walls defining the washing chamber 4 (for instance, in Fig. 4, which will be discussed in more detail, two connecting elements 32 are shown on opposite sides of the filter cover 22, which connecting elements 32 can be attached to opposite walls). As can be seen in Fig. 2 the supports 30 are located vertically spaced from the filter 20.

[0063] As can further be seen in Fig. 2, the filter cover 22 may suitably be provided with a lifting element 34, such as a hook or other suitable structure, which may facilitate lifting the filter cover 22 from its position on the supports 30, for example when it is desired to clean the filter 20. Such a lifting element 34 may for example be lifted by hand or by any suitable gripping or holding tool(s).

[0064] As best seen in Fig. 2, the filter 20 may have an outer perimeter defining the lateral extension L1 of the filter 20, wherein lateral extension L1 is transverse to vertical extension V. The filter cover 22 may suitably have a larger lateral extension L2 compared to the lateral extension L1 of the filter 20, such that the filter cover 22 extends laterally beyond the outer perimeter of the filter 20. Thus, because the lateral extension L2 of the filter cover 22 is larger than the lateral extension L1 of the filter 20, water moving downwardly from above the filter cover 22 (i.e. moving generally along said vertical extension V) will first become laterally deflected by the filter cover 22, then passed vertically along the filter cover 22, then become laterally returned below the filter cover 22 to the separation volume 24 between the filter cover 22 and the filter 20, and then passed through the filter 20.

[0065] As can be seen in Fig. 2 a gap 36 may be present between the filter cover 22 and the bottom wall 8. In this illustrated example there is a gap 36 at both lateral sides of the filter cover 22, however, in principle, it would be conceivable to only have a gap 36 at one of the lateral sides. Thus, water flowing from above the filter cover 22 can, after having become deflected, pass through the gaps 36 and then reach the separation volume 24 between the filter cover 22 and the filter 20. Thus, as can be understood from Fig. 2, the filter cover 22 may deflect water moving downwardly from above the filter cover 22 in at least two lateral directions, and wherein the water then reaches the separation volume 24 from at least two lateral directions.Furthermore, in addition to the illustrated gaps 36 being present between the filter cover 22 and the bottom wall 8, it may be conceivable to additionally have a one or more gaps between the filter cover 22 and at least one of the side walls 6.

[0066] As can be seen in Fig. 2, filter cover 22 may be substantially roof-shaped forming an upsidedown V-shaped cross-section. Thus, the filter cover 22 in the drawings figures has two inclined portions 38. In particular, the illustrated filter cover has a central apex 40 from which the inclined portions 38 extend downwardly. It should, however, be understood that in other examples the filter cover 22 may have just one inclined portion which extends oblique with respect to horizontal and vertical geometrical planes. For instance, the filter cover 22 could present one sloping plane all the way along the lateral extension L2. The idea of having one or more inclined portions 38 for the filter cover 22 is to reduce the risk of material accumulating on top of the filter cover 22. The supports 30, here in the form of the two illustrated brackets 30, may suitably present a sloping supporting surface which substantially conforms with the inclination of the inclined portions 38 of the filter cover 22. Hereby the filter cover 22 can be easily positioned and well supported.

[0067] The upside-down V-shaped cross-section of the filter cover 22 provides a functional advantage within the separation volume 24. While the upper side 28 deflects water and prevents debris accumulation, the lower side 26 acts as a hydrodynamic guide for separated air. As air bubbles separate from the downwardly moving water, their buoyancy causes them to rise and contact the lower side 26 of the inclined portions 38. The oblique angle of the inclined portions 38 actively guides these rising bubbles upwardly and inwardly toward the central apex 40. Once the bubbles reach the central apex 40, they are channeled longitudinally along the apex 40 until they reach the open ends of the filter cover 22, where they escape through the one or more apertures 42. This geometric configuration counteracts air stagnating beneath the cover and enables a continuous, directed evacuation of air away from the filter 20

[0068] Turning now to Figs. 3 and 4, it can be seen that the filter cover 22 may, in at least some examples provide escape routes for bubbles at the ends of the apex 40. As best seen in Fig. 4, the apex 40 of the filter cover 22 may suitably be elongated and have two opposite ends. Air bubbles that rise vertically in the separation volume 24 (shown in Fig. 2) will reaching the apex 40. Those bubbles will then be allowed to escape from the filter cover 22 via at least one of the ends of the apex 40 so as to continue to rise in the washing chamber 4. Here, in Figs. 3 and 4, there is illustrated an aperture 42 at the ends of the respective apex 40. As can be understood, the one or more apertures 42 may suitably be configured such that the air bubbles escape from the separation volume 24 at a higher vertical location than the vertical location of the gaps 36 through which the water enters the separation volume 24.In this example, the aperture 42 is present between the filter cover 22 and the connecting element 32 (there are two connecting elements 32 shown on opposite sides of the filter cover 22, which connecting elements 32 can be attached to opposite walls). In Figs. 3 and 4 an external side of a connecting element 32 is shown. The supports 30 shown in Fig. 2 are not visible in Figs. 3 and 4, but they may be provided on the internal side of the connecting elements 32. The connecting elements 32 may suitably also be used for holding the filter 20. In the example of Fig. 4, a filter 20 having three filtering screens is discernible.

[0069] Figs. 3 and 4 also illustrated that there may suitably be provided one lifting element 34 at each end of the filter cover 22 for lifting the filter cover 22 when the filter 20 is to be cleaned or replaced.

[0070] The structural arrangement described herein facilitates a highly effective method for reducing air entrainment in the circulation pump 18 of the medical washer-disinfector 1. During operation, the circulation pump 18 draws water downwardly from the washing chamber 4. To prevent air vortices and entrainment, this downwardly moving water is first deflected laterally by the filter cover 22, which acts as a physical obstruction. The deflected water is then allowed to enter the separation volume 24 located beneath the filter cover 22, typically via the lower first gap 36. Within this separation volume 24, the downward velocity of the water is sufficiently mitigated to allow the buoyant forces of entrained air bubbles to separate them from the water stream. The separated air bubbles are then allowed to escape upwardly from the separation volume 24 and rise into the washing chamber 4 through the second gap or aperture 42, which is located at a higher vertical level to prevent re-entrainment. Finally, the water, now having a substantially reduced air content, is passed through the filter 20 and into the circulation pump 18. This hydrodynamic separation method enables the circulation pump 18 to maintain satisfactory pressure even when operating with low water volumes, thereby satisfying both cleaning efficacy and environmental water-saving goals.

[0071] The disclosure includes medical washers-disinfectors and methods for effectively reducing the amount of air mixed with water entering a circulation pump. In particular, this disclosure includes a filter cover for enabling air bubbles to become separated from water before the water passes through a filter and into a circulation pump. Hereby, the risk of losing pressure at the circulation pump can be reduced. It should be understood that various features disclosed herein are contemplated and disclosed in their various combinations and sub-combinations.

Claims

CLAIMS1. A medical washer-disinfector, comprising:- a washing chamber configured to receive medical articles to be washed and / or disinfected, the washing chamber being at least partly defined by side walls and a bottom wall, wherein the washing chamber has a chamber outlet and one or more chamber inlets, wherein the chamber outlet is provided at the bottom wall and configured to allow water to be removed from the washing chamber through the chamber outlet,- a recirculation conduit extending from the chamber outlet to said one or more chamber inlets,- a circulation pump provided in the recirculation conduit and configured to, by means of its pumping action, cause water to be removed from the washing chamber and then recirculated in the recirculation conduit to the washing chamber through said one or more chamber inlets,- a filter provided in the chamber outlet, and- a filter cover provided in a lower part of the washing chamber, the filter cover being located above and vertically spaced from the filter such that a separation volume is present between the filter cover and the filter, wherein the filter cover is configured to deflect water in the washing chamber, drawn by the pumping action of the circulation pump and moving from above the filter cover, before the water reaches the separation volume below the filter cover and then passes through the filter.

2. The medical washer-disinfector according to claim 1 , wherein the filter cover has a lower side facing the filter and an opposite upper side facing away from the filter, the medicalwasher disinfector further comprising:- a support, such as comprising one or more brackets, which projects from one of the walls defining the washing chamber or from a connecting element attached to one of the walls defining the washing chamber, wherein the support is located vertically spaced from the filter and configured to receive and support the lower side of the filter cover.

3. The medical washer-disinfector according to any one of claims 1-2, wherein the filter has an outer perimeter defining the lateral extension of the filter, wherein lateral extension is transverse to vertical extension, wherein the filter cover has a larger lateral extension compared to the lateral extension of the filter, such that the filter cover extends laterally beyond the outer perimeter of the filter.

4. The medical washer-disinfector according to any one of claims 1-3, wherein water moving downwardly from above the filter cover is:- first laterally deflected by the filter cover,- then vertically passed along the filter cover,- then laterally returned below the filter cover to the separation volume between the filter cover and the filter, and- then passed through the filter.

5. The medical washer-disinfector according to any one of claims 1-4, wherein a gap is present between the filter cover and the bottom wall.

6. The medical washer-disinfector according to claim 5, wherein said gap is a first gap, wherein a second gap or aperture is present between the filter cover and at least one of the side walls.

7. The medical washer-disinfector according to claim 6, wherein the second gap or aperture is located at a higher vertical location than the first gap, and wherein the second gap or aperture is configured to allow air bubbles to escape from the separation volume into the washing chamber.

8. The medical washer-disinfector according to any one of claims 1-7, wherein the bottom wall tapers downwardly from the side walls towards the chamber outlet, wherein a horizontal geometrical plane cuts the filter cover and the tapering bottom wall.

9. The medical washer-disinfector according to any one of claims 1-8, wherein the filter cover has at least one inclined portion which extends oblique with respect to horizontal and vertical geometrical planes.

10. The medical washer-disinfector according to claim 9, wherein the filter cover has a central apex from which the at least one inclined portion extend downwardly.

11. The medical washer-disinfector according to claim 10, wherein the apex is elongated and has two opposite ends, wherein air bubbles rising vertically in the separation volume and reaching the apex are allowed to escape from the filter cover via at least one of the ends of the apex so as to continue to rise in the washing chamber.

12. The medical washer-disinfector according to any one of claims 10-11, wherein the lower side of the filter cover defines an inverted funnel configured to guide separated air bubbles rising within the separation volume upwardly along the at least one inclinedportion toward the central apex, and longitudinally along the central apex toward said at least one second gap or aperture.

13. The medical washer-disinfector according to any one of claims 1-12, wherein the filter cover deflects water moving downwardly from above the filter cover in at least two lateral directions, and wherein the water then reaches the separation volume from at least two lateral directions.

14. The medical washer-disinfector according to any one of the preceding claims, wherein the washing chamber is configured and dimensioned to receive a wash cart, and wherein a manifold of the wash cart is connectable to flow passages of the medical washerdisinfector to function as at least one of said chamber inlets.

15. A method for reducing air entrainment in a circulation pump of a medical washerdisinfector, the method comprising:- operating a circulation pump to draw water downwardly from a washing chamber, - deflecting the downwardly moving water laterally using a filter cover located above a filter,- guiding the deflected water to enter a separation volume located beneath the filter cover,- separating air bubbles from the water within the separation volume,- allowing the separated air bubbles to escape upwardly from the separation volume and rise into the washing chamber; and- passing the water with reduced air content through the filter to the circulation pump.

16. The method according to claim 15, wherein the act of deflecting the downwardly moving water laterally comprises forcing the water to travel along a tortuous path by first flowing laterally outwards along the filter cover, then vertically downwards, and then laterally inwards below the filter cover to enter the separation volume.

17. The method according to claim 15 or 16, wherein allowing the separated air bubbles to escape upwardly comprises guiding the rising air bubbles towards an elongated central apex of the filter cover and routing the air bubbles out of the separation volume via at least one open end of the elongated apex.

18. The method according to any one of claims 15 to 17, wherein allowing the deflected water to enter the separation volume comprises routing the water through a first gap defined between the filter cover and a bottom wall of the washing chamber, and whereinallowing the separated air bubbles to escape comprises routing the air bubbles through a second gap or aperture located at a higher vertical level than the first gap.

19. The method according to any one of claims 15 to 18, further comprising the act of introducing water into the washing chamber through a manifold of a wash cart that is docked within the washing chamber.

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