Cleaning device with a washing and rinsing arm rotation monitoring system

Description

Field of invention

[0001] The invention relates to a cleaning device, in particular a commercial dishwasher or a cleaning and disinfection device. The cleaning device comprises a wash chamber, a first movable spray arm, and a second movable spray arm. Both spray arms are arranged in the wash chamber and can be moved independently of each other. A first magnet is arranged on the first spray arm, and a second magnet is arranged on the second spray arm. The cleaning device also includes a measuring device with an effective range in which an electromagnetic quantity can be measured. background

[0002] Commercial dishwashers or cleaning and disinfection equipment in the medical sector must deliver reliable and rapid cleaning results. Therefore, it is desirable to monitor the rotation of the spray arms in such devices. This monitoring system should report an error if the spray arms become blocked in their rotation.

[0003] In a commercial dishwasher, for example, the spray arms become blocked if the user places dishes, such as cutlery or tall glasses, within the spray arms' range of motion. In this case, the spray arms collide with the dishes and stop rotating.

[0004] If the spray arms are blocked, the dishes won't be washed properly. Either the user doesn't notice this at all and removes dirty dishes from the dishwasher, or they only notice it after the cleaning cycle has finished. Neither poor cleaning results nor the wasted time are acceptable in a commercial setting.

[0005] A commercial dishwasher or a cleaning and disinfection device in the medical field may have different spray arms for the washing solution and the rinse water.

[0006] EP 1 743 566 shows a dishwasher with several stacked dish racks, each with a spray arm and a magnet mounted on the spray arm. Several magnetic sensors are arranged on one of the side walls of the tub. Description of the invention

[0007] The task is to provide a cleaning device that delivers a reliable cleaning result.

[0008] This problem is solved by the subject matter of the independent claim.

[0009] Accordingly, the cleaning device comprises a wash chamber in which the items to be cleaned, such as dishes or laboratory equipment, are arranged. The cleaning device is, in particular, a commercial dishwasher or a cleaning and disinfection unit used in the medical field. Furthermore, the cleaning device comprises a first movable spray arm and a second movable spray arm. Both spray arms are arranged in the wash chamber and can be moved independently of each other.

[0010] In particular, the cleaning device sprays washing solution onto the objects to be cleaned using the first spray arm and rinse water onto the objects to be cleaned using the second spray arm.

[0011] In particular, a cleaning program can be designed such that, in a first step, the first spray arm rotates and sprays cleaning solution onto the items to be cleaned. During this washing process, the second spray arm remains stationary. In a second step, the first spray arm is stationary and the second spray arm rotates. This second arm then sprays rinse water onto the items to be cleaned.

[0012] The cleaning device further comprises a first magnet and a second magnet. Both magnets are permanent magnets. The first magnet is arranged on the first spray arm, and the second magnet is arranged on the second spray arm.

[0013] The cleaning device also includes a measuring device with a detection range. If the first or second magnet moves through this range during operation, the measuring device can detect this movement.

[0014] The described cleaning device has the advantage that it can detect the movement of both the first spray arm, particularly the washing solution spray arm, and the second spray arm, particularly the rinse water spray arm. The cleaning device can thus monitor whether either spray arm is blocked in its movement. This monitoring ensures reliable cleaning results and allows malfunctions to be detected and reported immediately.

[0015] The measuring device comprises exactly one sensor. This sensor measures precisely one physical quantity, specifically an electromagnetic quantity. It can detect the movement of the first magnet and the movement of the second magnet. Manufacturing costs are correspondingly low when only a single sensor is used to detect the movement of two different spray arms.

[0016] Furthermore, the measuring device is designed as follows: If the first magnet moves through the measuring device's detection range, this movement of the first magnet, or the movement of the first spray arm, can be detected. This detection is also always possible when the second magnet is stationary, regardless of its position. Even when the second magnet is stationary within the measuring device's detection range, the device can still detect the movement of the first magnet. In other words, the second magnet cannot interfere with the measuring device to such an extent that it can no longer detect the first magnet.

[0017] Furthermore, the reverse functionality is also possible, i.e., the measuring device is designed as follows: If the first spray arm and the first magnet are at rest and the second spray arm moves with the second magnet, the measuring device can detect this movement independently of the stationary position of the first spray arm.

[0018] The described design has the advantage that the spray arm movements can be monitored permanently and reliably. Due to its resting position, a spray arm cannot interfere with the measuring device to such an extent that the measuring device can no longer detect the other spray arm.

[0019] In a particular embodiment, the measuring device is arranged outside the wash chamber. The wash chamber housing is thus positioned between the measuring device and the two magnets. Detection is nevertheless still possible. Arranging the measuring device outside the wash chamber has the advantage that it does not need to be protected from the washing solution. Furthermore, the arrangement and design of the measuring device does not require the wash chamber housing to be openable. This is particularly problematic in commercial hood-type dishwashers, where the entire hood must be accessible for opening.

[0020] In particular, the measuring device includes a sensor with adaptive threshold adjustment. This has the advantage that the measuring device can detect magnets at different distances equally well. Furthermore, the threshold of the measuring device can be adjusted if one magnet is stationary within the measuring device's detection range and the movement of a second magnet through the measuring device's detection range needs to be detected.

[0021] An advantageous measuring device is a fluxgate sensor or a geomagnetic sensor (e.g., Bosch BMM150 type), which comprises a flip-cor magnetic field sensor and a Hall sensor. These sensors are familiar to those skilled in the art and involve relatively low manufacturing costs.

[0022] In a particular embodiment, the movement of the first and second spray arms is a rotational movement. The first magnet is located at the outer end of the first spray arm, and the second magnet is located at the outer end of the second spray arm. "Outer end" means that the magnets on the spray arms are positioned furthest from the center of rotation. This arrangement allows the magnets to move as close as possible to the housing of the wash chamber during the rotation of the spray arms and therefore be reliably detected by a measuring device, particularly one located outside the wash chamber.

[0023] In particular, the first magnet and the second magnet are each arranged within a housing, especially one made of plastic. Specifically, the housings can be coupled to and decoupled from the first and second spray arms, respectively. The plastic housing protects the magnets from the effects of the wash and rinse water. The coupling capability allows for the replacement of a magnet.

[0024] Advantageously, the first and second magnets produce an equally strong magnetic field. This makes the design of the cleaning device particularly simple. The measuring device cannot distinguish whether the first or second spray arm is rotating. However, this is irrelevant, as the control system of the cleaning device knows which spray arm is rotating by controlling the corresponding pump. Specifically, the first magnet and / or the second magnet is a neodymium magnet.

[0025] In particular, the first magnet and the second magnet must be at least 50 mm, in particular at least 80 mm, in particular at least 90 mm, and / or a maximum of 150 mm away from the measuring device when moving through the effective area. The greater distance between the measuring device and the permanent magnets allows the measuring device to be positioned outside the washroom. However, a correspondingly sensitive measuring device must be provided.

[0026] In a particular embodiment, the cleaning device includes a control unit which is designed as follows: The control system rotates either the first spray arm by activating a first pump or the second spray arm by activating a second pump. Both spray arms do not rotate simultaneously; only one rotates at a time. The control system determines the rotation frequency based on signals from the measuring device. The control system issues an error message if the rotation frequency of the rotating spray arm falls outside a defined frequency band.

[0027] This is intended to ensure, for example, that the spray arm rotates at all. If the rotation frequency is zero or particularly low because the spray arm is blocked in its movement, the control unit issues an error message. If the blocked spray arm were not detected, this would result in poor cleaning performance, or the user would only notice the poor cleaning result after the cleaning process was complete when opening the washroom door.

[0028] In particular, the lowest frequency of the frequency band must be greater than 5 revolutions per minute, especially greater than 10 revolutions per minute, and especially greater than 20 revolutions per minute. If the specified frequency is not reached, a system error has occurred and an error message will be displayed.

[0029] Advantageously, the first spray arm and / or the second spray arm include a counterweight to the first magnet and / or the second magnet to prevent imbalance during the rotation of the first spray arm and / or the second spray arm. For example, if the magnet is located at one end of a spray arm, the counterweight should be located at the opposite end to achieve weight symmetry with respect to the axis of rotation. Brief description of the drawings

[0030] Further embodiments, advantages, and applications of the invention will become apparent from the dependent claims and from the following description with reference to the figures. These figures show: Fig. 1a the basic structure of a commercial dishwasher with a closed hood; Fig. 1b the basic structure of a commercial dishwasher with an open hood; Fig. 2 the measuring device and spray medium with two spray arms; Fig. 3a the situation in which the first spray arm rotates and the second spray arm is at rest within the effective range of the measuring device; and Fig. 3b the situation in which the second spray arm rotates and the first spray arm is at rest within the effective range of the measuring device. Method for implementing the invention Basic structure:

[0031] The commercial dishwasher according to the Fig. 1a and 1b It has a lower equipment compartment 1. Above this are a washroom 2 and a hood 3. The hood 3 forms the housing of the washroom 2.

[0032] In the present embodiment, the hood 3 is connected to the appliance compartment 1 via a rear wall 4 of the appliance. The hood 3 is height-adjustable and can move up and down along the rear wall 4. Fig. 1a The wash chamber 2 is closed. The hood 3 is in its lowest position. If the user wishes to open wash chamber 2 to remove or load dishes, they lift the hood 3 by the handle 31. The hood 3 moves upwards along the rear wall 4 to its maximum uppermost position, as shown in Fig. 1b As shown. When the hood 3 is open, dish baskets 5 can be inserted into and removed from the appliance.

[0033] In washroom 2, upper spray devices 6a and lower spray devices 6b are located. Fig. 1a and 1b These are only shown schematically. However, how with regard to Fig. 2As described in more detail, each spray consists of a first spray arm 61 and a second spray arm 62.

[0034] Furthermore also from the Fig. 1a and 1b The schematic diagram shows a washing solution tank 11 below the wash chamber 2 and a first pump 12 to pump cleaning fluid from the washing solution tank 11 upwards into the spray nozzles 6a and 6b, from where it enters the wash chamber 2 and, for example, flows back into the washing solution tank 11. A second pump 13 is also provided to pump rinse water from a fresh water tank 14 into the spray nozzles 6a and 6b. Structure of the spray arms and the measuring device:

[0035] The Fig. 2Figure 6a shows the spray device 6a from below. The spray device 6a comprises a first spray arm 61 and a second spray arm 62. The first spray arm 61 sprays washing solution onto the dishes to wash them. The second spray arm 62 sprays rinse water onto the dishes to rinse them after washing. The washing solution sprays through openings 63 located on the first spray arm 61, and the rinse water sprays through openings 64 located on the second spray arm 62.

[0036] The first spray arm 61 and the second spray arm 62 rotate around the same center of rotation 65. However, the rotation of the two spray arms 61 and 62 is independent of each other. In the present embodiment, only either the first spray arm 61 or the second spray arm 62 rotates. While the first spray arm 61 is rotating, the second spray arm 62 remains at rest in an arbitrary position. While the second spray arm 62 is rotating, the first spray arm 61 remains at rest in an arbitrary position.

[0037] A first permanent magnet 71 is arranged at the outer end of the first spray arm 61. A second permanent magnet 72 is arranged at the outer end of the second spray arm 62. Both permanent magnets 71 and 72 are protected by plastic housings 73 and 74, respectively. The plastic housings 73 and 74 containing the permanent magnets 71 and 72 can be removed from the spray arms 61 and 62. The permanent magnets 71 and 72 are of the same size and are, for example, neodymium magnets.

[0038] Also visible is in Fig. 2 A part of the wall of hood 3, which encloses washroom 2. Hood 3 thus forms the housing of washroom 2.

[0039] A measuring device 8 is arranged outside the washroom 2. "Outside the washroom 2" means that the washroom housing, i.e., in the present embodiment the wall of the hood 3, is located between the measuring device 8 and the washroom 2. The measuring device 8 is configured to detect the movement of the permanent magnets 71 and 72 within its effective range 81. When the permanent magnets 71 and 72 move through the effective range 81, the minimum distance D between the measuring device 8 and the permanent magnets 71 and 72 is approximately 80 mm.

[0040] The measuring device 8 comprises exactly one single sensor. In the present embodiment, this is a fluxgate sensor, which is a sensor with adaptive threshold adjustment. Performing a measurement:

[0041] The measuring device 8 is suitable for detecting the movement of the two permanent magnets 71 and 72 through the effective area. The measuring device 8 cannot distinguish between the two permanent magnets 71 and 72. Upon each detection, the measuring device 8 sends a signal to the control unit 9, which is schematically represented in Fig. 1a and 1b is marked.

[0042] The control unit 9 uses the signals to determine the rotational frequency of the rotating spray arm 61 or 62. The determined rotational frequency is compared with a predetermined target frequency band. For this embodiment, the frequency band ranges from 20 to 120 revolutions per minute. If the spray arms 61 and 62 rotate within this frequency range, a satisfactory cleaning result is expected. However, if the rotational frequency falls below the minimum of 20 revolutions per minute, the control unit detects a malfunction of the cleaning device and displays a visual error message and an audible alarm via the indicator 32. If the measured rotational frequency is too low, an unsatisfactory cleaning result must be expected.

[0043] The error message prompts the user to open hood 3 to check if any dishes are blocking the rotation of spray arms 61 and 62. Once the user has resolved the issue, they close hood 3 and the cleaning process can continue.

[0044] During operation, either the first spray arm 61 rotates and sprays washing solution onto the dishes, or the second spray arm 62 rotates and sprays rinse water onto the dishes. The other spray arm remains stationary. Measuring the rotational frequency of the rotating spray arm 61 or 62 is generally straightforward. However, the situation where the stationary spray arm, with its permanent magnet, is at rest within the effective range 81 of the measuring device 8 presents a particular challenge.

[0045] This situation is in the Figs. 3a and 3b illustrated. At the in Fig. 3aIn the situation shown, the second spray arm 62 and the second permanent magnet 72 are at rest within the effective range 81. The first spray arm 61 with the first permanent magnet 81 rotates. In order to still be able to detect the movement of the first permanent magnet 71 through the effective range 81 in this situation, a sensor with adaptive threshold adjustment is provided as a measuring device 8.

[0046] In Fig. 3b The reverse situation is shown. The first spray arm 61 is at rest, and the first permanent magnet 71 is at rest within the effective range 81. The second spray arm 62 rotates. In this situation as well, the measuring device 8 with adaptive threshold adjustment can detect the movement of the second permanent magnet 72 through the effective range 81.

[0047] The dishwasher can also have additional spray nozzles and clean multiple dish racks simultaneously.

[0048] While preferred embodiments of the invention are described in the present application, it should be clearly pointed out that the invention is not limited to these and can also be carried out in other ways within the scope of the following claims.

Claims

1. Cleaning device, in particular a commercial dishwasher or a washer-disinfector, comprising - a washing chamber (2), - a first movable spray arm (61) and a second movable spray arm (62), both arranged in the washing chamber (2) and movable independently of one another, in particular rotatable, - a first magnet (71) arranged on the first spray arm (61) and a second magnet (72) arranged on the second spray arm (62), - a measuring device (8) for detecting the first magnet (71) and the second magnet (72) in an effective range (81) of the measuring device (8), wherein the measuring device (8) comprises exactly one single sensor which can measure exactly one physical quantity, wherein the first spray arm (61) and the second spray arm (62) are adapted in such a way that, in operation, the first magnet (71) moves by means of a first movement and the second magnet (72) moves by means of a second movement through the effective range (81) of the measuring device (8), characterised in that the measuring device (8) is adapted in such a way that - the measuring device (8) can detect the first movement of the first magnet (71) through the effective range (81) while the second magnet (72) is at rest at any position in the effective range (81), and / or - wherein the measuring device (8) can detect the second movement of the second magnet (72) through the active area (81) while the first magnet (71) is at rest at any position in the active area (81).

2. Cleaning device according to claim 1, wherein the cleaning device is adapted in such a way that the first spray arm (61) sprays, in particular only, detergent solution and the second spray arm (62) sprays, in particular only, rinse water.

3. Cleaning device according to one of the preceding claims, wherein the exactly one physical quantity is an electromagnetic quantity.

4. Cleaning device according to one of the preceding claims, wherein the measuring device (8) is adapted in such a way that - the measuring device (8) can detect the first movement of the first magnet (71) through the effective range (81) while the second magnet (72) is not moving and irrespective of the position at which the second magnet (72) is located during the detection of the first magnet (71), in particular while the second magnet (72) is at rest in the effective range (81), and / or - the measuring device (8) can detect the second movement of the second magnet (72) through the effective range (81) while the first magnet (71) is not moving and irrespective of the position at which the first magnet (71) is located during the detection of the second magnet (72), in particular while the first magnet (71) is at rest in the effective range (81).

5. Cleaning device according to one of the preceding claims, wherein the measuring device (8) is arranged outside the washing chamber (2).

6. Cleaning device according to one of the preceding claims, wherein the measuring device (8) comprises, in particular is, a sensor with adaptive threshold adjustment.

7. Cleaning device according to one of the preceding claims, wherein the measuring device (8) comprises - a fluxgate sensor, or - a geomagnetic sensor comprising a Flipcor sensor and a Hall sensor.

8. Cleaning device according to one of the preceding claims, wherein the first spray arm (61) and the second spray arm (62) are arranged rotatably and wherein the first magnet (71) is arranged at the outer end of the first spray arm (61) and the second magnet (72) is arranged at the outer end of the second spray arm (62).

9. Cleaning device according to one of the preceding claims, wherein the first magnet (71) and the second magnet (72) are each arranged within a housing (73, 74), in particular consisting of a plastic, and the housing (73, 74) can each be coupled to or decoupled from the first spray arm (61) and the second spray arm (62).

10. Cleaning device according to one of the preceding claims, wherein the first magnet (71) and the second magnet (72), - have a magnetic field of the same magnitude, and / or - are neodymium magnets.

11. Cleaning device according to one of the preceding claims, wherein the first magnet (71) and the second magnet (72) are spaced at least 5 mm, in particular at least 10 mm, and / or at most 150 mm, in particular at most 90 mm, from the measuring device (8) during the movement through the effective range (81).

12. Cleaning device according to one of the preceding claims, comprising a control unit (9) which is adapted in such a way that - either the first spray arm (61) rotates by activating a first pump (12) or the second spray arm (62) rotates by activating a second pump (13), - the control unit (9) determines a rotation frequency on the basis of the signals from the measuring device (8), - the control unit (9) outputs an error if the rotation frequency of the rotating spray arm (61, 62) is outside a defined frequency band.

13. Cleaning device according to claim 12, wherein the lowest frequency of the frequency band is greater than 5 revolutions per minute, in particular greater than 10 revolutions per minute, in particular greater than 20 revolutions per minute.

14. Cleaning device according to one of the preceding claims, wherein the first spray arm (61) and / or the second spray arm (62) have a counterweight to the first magnet (71) and / or to the second magnet (72), for preventing an imbalance during the rotational movement of the first spray arm (61) and / or the second spray arm (62).