METHOD FOR WASHING AND DISINFECTING OBJECTS

Abstract

Methods and devices for washing and disinfecting objects in a washer-disinfector having at least one chamber. Steps include circulating water and detergent in the chamber, rinsing the objects in the chamber by spraying non-circulating pressurized water in the chamber, draining the chamber, and disinfecting the objects. The steps of rinsing the objects and draining the chamber can be performed at least partially simultaneously. The present invention allows for reduced water and energy consumption compared to prior art, while at the same time decreasing the risk for transfer of process residuals compared to when no rinsing is performed.

Claims

1. A method for washing and disinfecting objects in a washer-disinfector comprising at least one chamber, said method comprising the steps of: washing said objects in said chamber by circulating water and detergent in said chamber; rinsing the objects in said chamber by spraying non-circulating pressurized water in said chamber; draining said chamber; and disinfecting said objects, wherein the steps of rinsing the objects and draining said chamber are performed at least partially simultaneously.

2. A method according to claim 2, wherein said step of disinfecting said objects is performed in the chamber, and comprises using thermal disinfection.

3. A method according to claim 3, wherein the step of disinfecting said objects comprises circulating water in said chamber, said water having a temperature of 80-95 C.

4. A method according to claim 1, wherein said method further comprises a second step of draining said chamber, said second step of draining being performed after the step of disinfecting said objects.

5. A method according to claim 2, wherein said non-circulating pressurized water used for rinsing the objects has substantially the same temperature as the water used for disinfecting said objects.

6. A method according to claim 2, wherein said water used for rinsing the objects by spraying non-circulating pressurized water, and the water used for disinfecting said objects, are supplied from a common water tank.

7. A method according to claim 7, wherein said water used for washing said objects is supplied from a water source separate from said common water tank.

8. A method according to claim 1, wherein said step of rinsing the objects comprises spraying said non-circulating pressurized water using a set of oscillating nozzles.

9. A method according to claim 8, wherein said set of oscillating nozzles is a first set, and the step of washing said objects in said chamber comprises using a separate second set of oscillating nozzles for distributing the circulating water.

10. A method according to claim 1, wherein said method further comprises a step of drying said objects, said step being performed after the step of disinfecting said objects.

11. A method according to claim 1, further comprising collecting at least a part of the water used for rinsing the objects, and reusing said water in the step of washing said objects in a later repetition of said method.

12. A method according to claim 1, wherein said washer-disinfector is a cart washer-disinfector adapted for receiving a cart at ground level.

13. A washer-disinfector, the washer disinfector comprising a chamber and at least one door for accessing the chamber, wherein the washer-disinfector is configured to perform the method of claim 1.

14. A method for washing and disinfecting objects in a washer-disinfector comprising at least one chamber, said method comprising the steps of: washing said objects in said chamber by circulating water and detergent in said chamber, and then draining the chamber; after said washing, rinsing the objects in said chamber by spraying non-circulating pressurized water in said chamber; draining the chamber after said rinsing; disinfecting said objects; after said disinfecting, rinsing the objects in said chamber by spraying non-circulating pressurized water in said chamber; and draining the chamber.

15. The method of claim 14: wherein both of said rinsing steps are performed by spraying non-circulating pressurized heated water in said chamber; and wherein the disinfection step comprises thermal disinfection, the thermal disinfection comprising circulating heated water in the chamber; wherein water from the disinfection step is collected after the disinfection step, heated, and used in one or more disinfection steps in subsequent washing and disinfection cycles.

16. The method of claim 14: performing a pre-rinse before said washing, the pre-rinse comprising spraying water; and wherein the disinfection step comprises thermal disinfection, the thermal disinfection comprising circulating heated water in the chamber; wherein water from the disinfection step is collected after the disinfection step, heated, and used in one or more disinfection steps in subsequent washing and disinfection cycles.

17. The method of claim 14: wherein both of said rinsing steps are performed by spraying non-circulating pressurized heated water in said chamber using a plurality of first nozzles while oscillating the first nozzles; wherein the disinfection step comprises thermal disinfection, the thermal disinfection comprising circulating heated water in the chamber using a plurality of second nozzles while oscillating the second nozzles; wherein said washing is performed by circulating water and detergent using the second nozzles; wherein at least one of the rinsing steps occurs while the chamber is simultaneously being drained.

18. A device for washing and disinfecting objects, the device comprising: a chamber for holding objects therein, and a door for accessing the chamber; a plurality of first nozzles, the first nozzles being configured for oscillating and fluidically connected for spraying non-circulating pressurized water in the chamber; a plurality of second nozzles, the second nozzles being configured for oscillating and for spraying circulating liquid in the chamber; wherein at least the first nozzles are fluidically connected to a water tank, the water tank being configured for heating water therein; wherein the second nozzles have larger diameters than the first nozzles, the second nozzles having greater fluid flow capacity than the first nozzles; the chamber comprising a drain which is fluidically connected to a re-use tank, the re-use tank being adapted for receiving fluid from the chamber after the fluid has been used for one of washing and disinfecting, and then for returning the fluid to the chamber for reuse in the chamber.

19. The device of claim 18, the device being configured for: washing objects in the chamber by circulating water and detergent in said chamber using the second nozzles, and then draining the chamber; after said washing, rinsing the objects in the chamber by spraying non-circulating pressurized water in said chamber using the first nozzles; draining the chamber after said rinsing; disinfecting the objects be receiving heated water in the chamber, and circulating the heated water using the second nozzles; after said disinfecting, rinsing the objects in the chamber by spraying non-circulating pressurized water using the first nozzles; and draining the chamber; wherein at least one of the draining steps overlaps with draining the chamber.

20. The device of claim 18, wherein the device is a cart washer-disinfector adapted for receiving a cart at ground level, the cart carrying objects for washing and disinfecting; the device being configured for: washing objects in the chamber by circulating water and detergent in said chamber using the second nozzles, and then draining the chamber; after said washing, rinsing the objects in the chamber by spraying non-circulating pressurized water in said chamber using the first nozzles; draining the chamber after said rinsing; disinfecting the objects be receiving heated water in the chamber, and circulating the heated water using the second nozzles; after said disinfecting, rinsing the objects in the chamber by spraying non-circulating pressurized water using the first nozzles; and draining the chamber; wherein at least one of the draining steps overlaps with draining the chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] For exemplifying purposes, the invention will be described in closer detail in the following with reference to the appended drawings showing at least five different exemplary embodiments of the invention.

[0047] FIG. 1 is a flowchart of a first exemplary embodiment of a method according to the first aspect of the present invention.

[0048] FIG. 2 is a flowchart of a second exemplary embodiment of a method according to the first aspect of the present invention.

[0049] FIG. 3 is a flowchart of a third exemplary embodiment of a method according to the first aspect of the present invention.

[0050] FIG. 4 is a flowchart of a fourth exemplary embodiment of a method according to the first aspect of the present invention.

[0051] FIG. 5 is a schematic illustration of an exemplary embodiment of a washer-disinfector according to the second and/or third aspect of the present invention, adapted for performing a method according to the first aspect of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0052] In the following detailed description exemplary embodiments of the present invention will be described. However, it is to be understood that features of the different embodiments are exchangeable between the embodiments and may be combined in different ways.

[0053] FIG. 1 shows a flowchart of a method of washing and disinfecting objects in a washer disinfector, according to at least a first exemplary embodiment of the first aspect of the present invention. After start (e.g., step 10), the first step of said first exemplary embodiment is the step of washing the objects (e.g., step 15). During this step, water and a detergent is circulated in a chamber of the washer-disinfector. A set of oscillating nozzles is used for the circulation. When the process is performed in a cart washer-disinfector, this step uses approximately 150 litres of water. This water can be taken directly from a water supply network. Alternatively, it may be taken from a water tank. In some embodiments, the water used for washing may be mixed with waste water from a previous iteration of the method.

[0054] After the wash, two steps are performed in parallel: drain (e.g., step 25) and Direct Rinse (e.g., step 20). The Direct Rinse-step comprises rinsing the objects in said chamber by spraying non-circulating pressurized water over them. In this embodiment, Direct Rinse is performed using a set of nozzles other than the set used for the step of washing the objects. The set of nozzles used for Direct Rinse may have smaller orifices, and hence give a lower flow rate, than the set of nozzles used for washing the objects. The water for Direct Rinse is in this first embodiment taken from a pre-heated water tank. A pump is used to supply the water to the nozzles and to achieve a pressurization. The temperature of the water in the water tank can be adjusted. In this first exemplary embodiment, the temperature of the water in the water tank may be 90 C.

[0055] During the step of draining, the chamber is emptied of the water used for the wash as well as the water used for the Direct Rinse. The drain- and Direct Rinse-steps are allowed to be performed simultaneously since the water used for rinsing in Direct Rinse is not circulated in the chamber.

[0056] When the method according to the exemplary embodiment is performed in a cart washer-disinfector, the Direct Rinse-step uses 10-30 litres of water.

[0057] After the Direct Rinse and draining of the chamber have been performed, a disinfection (e.g., step 30) is performed. In this first exemplary embodiment, this step comprises circulating water with a temperature of 90 C. in said chamber. The water is taken from the same water tank as the water used for the Direct Rinse, but for the step of disinfecting the objects the water is supplied through the same set of nozzles as is used for the step of washing the objects. This is advantageous since the larger orifices comprised by this set of nozzles are more efficient when circulating water, since they provide a higher flow rate.

[0058] After the objects have been disinfected, this first exemplary embodiment comprises another step of draining the chamber (e.g., step 35), to remove the water used for the step of disinfecting the objects. After this a final step of drying the objects is performed (e.g., step 40). In this embodiment, drying is achieved by heating the air inside the chamber. After drying, the process is complete (e.g. step 45).

[0059] FIG. 2 shows a flowchart of a method according to a second exemplary embodiment of the first aspect of the present invention. This embodiment comprises the steps of start (e.g., step 50), washing (e.g., step 65), rinsing using Direct Rinse (e.g., step 70), draining (e.g., step 75), disinfecting (e.g., step 80), draining (e.g., step 85) and drying the objects (e.g., step 90) in accordance with the first exemplary embodiment. After drying, the process is complete (e.g., step 95). The method according to this second embodiment further comprises a step called Direct Pre Rinse (e.g., step 55), performed at the beginning of the process. This step is performed in the same way as the step Direct Rinse. Non-circulating pressurized water is sprayed over the objects in said chamber. In this embodiment, this is done using the same set of nozzles as is used for the Direct Rinse. The water may be taken from the same water tank as for Direct Rinse and disinfection. Alternatively, the water may be taken from the water supply network or from a separate water tank. If the soil on the objects contains proteins, for example blood, it is advantageous to use cold water for the Direct Pre Rinse. Direct Pre Rinse is followed by an additional step of draining said chamber (e.g., step 60).

[0060] The purpose of adding a step of Direct Pre Rinse may be to further reduce transfer of residuals, in this case residuals being soil, and to efficiently rinse the objects using a limited amount of water before washing them.

[0061] FIG. 3 shows a flowchart of a method according to a third exemplary embodiment of the first aspect of the present invention. This embodiment comprises the steps of start (e.g., step 100), washing (e.g., step 105), rinsing using Direct Rinse (e.g., step 110), draining (e.g., step 115), disinfecting (e.g., step 120), draining (e.g., step 130) and drying the objects (e.g., step 135) in accordance with the first exemplary embodiment. After drying, the process is complete (e.g., step 140) The method according to this third embodiment further comprises a step called Direct Final Rinse (e.g., step 125), performed after the step of disinfecting the objects. This is a repetition of the Direct Rinse-step. Non-circulating pressurized water is sprayed over the objects in said chamber. This may be done using the same set of oscillating nozzles as for Direct Rinse. Alternatively, the same set of oscillating nozzles as are used for washing may be used. The water used for Direct Final Rinse may be taken from the same water tank that supplies water for disinfection and Direct Rinse. Alternatively, the water may be taken from the water supply network, or from a separate water tank.

[0062] The purpose of adding a step of Direct Final Rinse may be to further reduce process residuals on the objects, especially if the high quality of the water used for disinfection is limited.

[0063] FIG. 4 shows a flowchart of a method according to a fourth exemplary embodiment of the first aspect of the present invention. This embodiment is a combination of the first, second and third embodiments; it comprises the steps of start (e.g., step 145), washing (e.g., step 160), rinsing using Direct Rinse (e.g., step 165), draining (e.g., step 170), disinfecting (e.g., step 175), draining (e.g., step 185) and drying the objects (e.g., step 190) in accordance with the first exemplary embodiment. After drying, the process is complete (e.g., step 195). The fourth embodiment further comprises the Direct Pre Rinse (e.g., step 150) and additional draining (e.g., step 155) in accordance with the second exemplary embodiment, as well as the Direct Final Rinse (e.g., step 180) in accordance with the third exemplary embodiment. The purpose of including both Direct Pre Rinse and Direct Final Rinse, in addition to the step of Direct Rinse, may be to further limit the transfer of process residuals between the phases of the process.

[0064] FIG. 5 shows a schematic illustration of a washer-disinfector 1 according to an exemplary embodiment of the second and/or third aspect of the present invention. The washer-disinfector is adapted for performing a method according to the first aspect of the present invention. The washer-disinfector 1 comprises a chamber 2 where the objects may be placed, a preheated water tank 3, a first pump 4, a first set of nozzles 5, a water source 6, a second set of nozzles 7, a second pump 8, and an outlet for waste water 9. The way water may flow between the different parts of the machine is illustrated with arrows in the figure.

[0065] The washer-disinfector 1 may be a cart washer-disinfector or an instrument washer-disinfector. The water source 6, the second set of nozzles 7 and the second pump 8 may constitute or be comprised in means for washing objects in the chamber 2 by circulating water and detergent therein. The preheated water tank 3, the first pump 4 and the first set of nozzles may make up or be comprised in means for rinsing the objects in the chamber 2 by spraying non-circulating pressurized water therein. Means for draining the chamber 2 may comprise or be provided by the waste water outlet 9. The preheated water tank 3 together with the second set of nozzles 7 and the second pump 8 may provide or be comprised in means for disinfecting the objects. The washer-disinfector 1 is configured so that rinsing the objects by spraying non-circulating pressurized water in said chamber 2 and draining said chamber 2 may be performed at least partially simultaneously.

[0066] The water source 6 may be a water supply network or a water tank. The water source 6 may provide water directly to the chamber 2, and it may also optionally provide water to the preheated water tank 3. In an alternative embodiment, the preheated water tank 3 may be omitted, so that water is supplied directly from the water source 6 via the first pump 4 to the first set of nozzles 5.

[0067] The second set of nozzles 7 may comprise larger orifices than the first set of nozzles 5, allowing a higher flow rate. This is advantageous since the second set of nozzles 7 is adapted to be used for circulating a relatively large volume of water, while the first set of nozzles 5 is adapted for spraying non-circulating pressurized water.

[0068] FIG. 5 is a schematic illustration of a washer-disinfector 1, hence not all components are included in the illustration. For example, conventional means for circulating and transporting water such as conduits may also be part of the washer-disinfector 1.

[0069] A method according to the first exemplary embodiment of the present invention, described in relation to FIG. 1, may be explained further in relation to the washer-disinfector 1 illustrated in FIG. 5. During the first step of the method, washing the objects 15, water is taken from the water source 6. The water is supplied to the chamber 2 holding the objects and circulated therein using the second set of nozzles 7 and the second pump 8. The water is circulated together with a detergent.

[0070] After the step of washing the objects, the chamber is drained 25. During this step, the circulated water and detergent is emptied out through the waste water outlet 9. During draining, the Direct Rinse-step 20 is also performed. Water is taken from the preheated water tank 3, which may be filled with water from the water source 6, and supplied to the first set of nozzles 5 using the first pump 4. From the first set of nozzles 5, the water is sprayed over the objects. The water used for Direct Rinse is not circulated in the chamber 2. This water is also drained through the waste water outlet 9, together with the wash water. The waste water may be collected and at least a part of it may be reused in a later repetition of the method.

[0071] After the Direct Rinse and draining have been completed, the disinfection 30 is performed. During this step, water is taken from the preheated water tank 3 and circulated in the chamber 2 using the second set of nozzles 7, i.e. the same set of nozzles as were used for the step of washing the objects, and the second pump 8. After the disinfection is completed, the water in the chamber is drained 35 through the waste water outlet 9. This water may also be collected and at least a part of it may be reused in a later repetition of the method. Finally, the objects in the chamber are dried 40 by heating the air inside the chamber.

[0072] The washer-disinfector 1 described in relation to FIG. 5 may also be used to perform any of the other exemplary embodiments of the invention.

[0073] The steps diagrammed in FIG. 4 can be performed with some or all of the rinsing steps in the flowchart. For example, with or without the pre-rinse 150, with or without the direct rinse 165 after the wash, and with or without the direct final rinse 180 after disinfection. Some or all of the rinses 150, 165, 180 may be performed using uncirculated heated water.

[0074] In a particular embodiment, the direct rinse 165 is performed with uncirculated hot water having the same temperature, or within 5 or 10 degrees Celsius of the temperature, of a subsequent hot water disinfection step. This (i) pre-warms the goods and chamber, and also (ii) removes any residuals left over from the circulating wash. Goods entering the disinfection step are thus free of most or all physical contaminants, so that the heat disinfection water remains relatively clean and can be reused. For example, reused in subsequent disinfection cycles, washing cycles, and/or pre-rinses.

[0075] A direct final rinse 180 after disinfection can be applied to remove any physical contaminants that may remain on the goods after disinfection. This makes it further possible to reuse circulating disinfection liquid, since reused liquid has increased risk of containing contaminants. Optionally, final rinse water may be saved (optionally together with disinfection water) for use in future cycles.

[0076] A pre-rinse 150 can be used (heated or unheated water) to remove most contaminants (e.g. bodily fluid or waste) prior to the circulating wash step 160. Typically the pre-rinse water is drained before the wash step, optionally while the pre-rinse is ongoing. Pre-rinsing keeps the wash step fluid relatively clean, and in some embodiments allows reuse of water and detergent in subsequent wash cycles. The pre-rinse may be a circulated rinse, or a non-circulated direct rinse. The pre-rinse may be performed with water saved from past wash cycles, such as recycled wash fluid, or recycled disinfection water.

[0077] Notably, rinse steps such as direct rinses may be performed using substantially less fluid (e.g. less heated water) than circulating wash or disinfection steps. Short rinse steps using smaller volumes of water can be paired with longer circulating wash and/or disinfection steps to provide both effective cleaning, shorter cycles, water efficiency, and energy/heating efficiency. The absolute volumes can vary based on chamber size and other variables. Rinse steps may be performed, for example, using 10-30, 10-60, 3-60, 5-30, or 5-60 litres of water. Circulating steps (washing or disinfection) may be performed using, for example, 100-200, 50-250, 75-200, 100-300, or 75-400 litres of liquid. The volume of liquid used in any or all of the respective rinse steps may be, as a percentage of the volume of liquid used in a prior or subsequent wash steps and/or disinfection steps: less than 50%, less than 40%, less than 25%, 1-75%, 2-50%, 3-60%, 5-50%, 10-50%, 5-25%, or 2-30%.

[0078] A direct rinse can be provided as a rinse using non-circulated water, sprayed directly on the goods being cleaned. For example, water directly from a city water system, or water from a tank holding clean water, which may be hateable. Direct rinses, employed strategically, can allow reuse of washing and/or disinfection fluid (to save water and energy) while minimizing residuals on the goods at the end of the cycle.

[0079] In some embodiments, rinses and/or direct rinses are performed by shooting fluids from nozzles at a greater pressure than the pressure of fluid leaving nozzles in washing and/or disinfection steps. The higher-pressure may be provided by nozzles having a smaller diameter and/or pumps operating to provide greater pressure. For example, a plurality of first nozzles can be configured for oscillating and fluidically connected for spraying non-circulating, pressurized water in the chamber. A plurality of second nozzles can also configured for oscillating and for spraying circulating liquid in the chamber during washing and disinfection, but at a lower pressure/velocity than the first nozzles. The first nozzles may have a smaller diameter than the second nozzles, contributing to greater pressure and velocity.

[0080] Some methods and devices utilise tanks for receiving and retaining heated liquid from one cycle for reuse in one or more subsequent cycles. Such chambers may include heating elements to warm the fluid therein. For example, water, warmed water, or a water detergent mix from wash cycles.

[0081] Reusing warm liquid saves both water and energy used to heat the water, and can reduce total process time by reducing heating times.

[0082] In some embodiments, the disclosed processes (e.g. in flow charts) are limited to and consist only of the specifically disclosed rinsing, washing, disinfecting, and/or draining steps, to the exclusion of additional steps. All embodiments in the written description and drawings herein are optionally limited to the disclosed steps and features only, to the exclusion of additional steps and/or features. Some embodiments are limited to the disclosed series of rinses only, to the disclosed washing and disinfection steps only, or both. All embodiments are contemplated and disclosed in both open (allowing more steps/elements) and closed (excluding additional steps elements) form, both as a whole and with respect to individual steps and elements.

[0083] The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. Different features of the present invention may be combined to create embodiments other than those described, and many modifications and variations are possible within the scope of the appended claims. For example, chemical disinfection may be used instead of thermal disinfection, and the method may be applied to instrument washer-disinfectors instead of cart washer-disinfectors. The steps of the method may be performed in any appropriate order, and the method is not limited to the order of the steps described herein. Features and steps described with respect to methods are disclosed with respect to corresponding devices and arrangements arranged for performing such methods, and vice versa.