Calcium / scale removal system of utensil washing machine

Abstract

A ware washing machine includes a chamber for receiving a ware, the chamber having at least one spray zone in which liquid can be recirculated from a tank to a spray assembly for spraying the liquid onto the ware. The decalcification system is configured to deliver a decalcification solution to the tank. The controller is configured to operate in at least one vessel cleaning mode and at least one calcium removal mode of operation. The controller is configured such that, in a calcium removal mode of operation, the calcium removal system is controlled to perform a calcium removal operation wherein the controller (i) controls the calcium removal system to deliver the calcium removal solution into the tank and (ii) performs an acidity reduction process to reduce the acidity of the calcium removal solution.

Description

Technical Field

[0001] The present application generally relates to dishwashing machines, such as dishwashing machines used in commercial applications such as cafes and restaurants, and more particularly to a descaling system for a dishwashing machine. Background Art

[0002] Commercial kitchens often utilize dishwashing machines that require regular cleaning, including descaling as appropriate, where scale or lime needs to be removed from the water flow path along the rinse line (including hot water boosters, energy recovery units, plate heat exchanger units, and / or rinse pipes). Some machines include integrated and automated descaling systems. Some machines use an automatic drain valve or drain pump to automatically drain the descaling solution from the machine at the end of the descaling solution cycle. However, some machines include standpipes in the machine(s) tank(s) that need to be manually raised by an operator to drain the tank(s) at the end of the descaling solution cycle. Other machines include manual drain valves.

[0003] There is a desire to provide a dishwashing machine and an associated descaling system that take into account that an operator may not be able to drain the descaling solution in a timely and correct manner. Summary of the Invention

[0004] In one aspect, a dishwashing machine includes: a chamber for receiving dishes, the chamber having at least one injection zone in which liquid can be recirculated from a tank to an injection assembly for injecting the liquid onto the dishes. A descaling system is configured to deliver a descaling solution to the tank. A controller is configured to operate in at least one dishwashing mode and at least one descaling operation mode. The controller is configured such that in the descaling operation mode, the descaling system is controlled to perform a descaling operation, wherein the controller (i) controls the descaling system to deliver the descaling solution into the tank and (ii) performs an acidity reduction process to reduce the acidity of the descaling solution by at least one of the following: (i) causing fresh water to be delivered into the tank or (ii) causing a detergent to be delivered into the tank.

[0005] In the case of delivering fresh water into the tank, the acidity is reduced by diluting the liquid / solution in the tank. In the case of delivering a detergent into the tank, the acidity is reduced by the neutralization of the detergent.

[0006] In another aspect, a dishwashing machine for washing dishes includes: a chamber configured to receive dishes, the chamber having at least one injection zone in which liquid can be recirculated from a reservoir to an injection assembly for injecting the liquid onto the dishes, the reservoir including a discharge member that must be manually moved to discharge the reservoir; a descaling system configured to deliver a descaling solution to the reservoir; and a controller configured to operate in at least one dishwashing mode and at least one descaling operation mode. In the descaling operation mode, the descaling system is controlled to perform a descaling cycle, wherein the controller: controls the descaling system to deliver the descaling solution into the reservoir and then circulates the descaling solution; and monitors whether the discharge of the reservoir occurs after the end of the circulation of the descaling solution, and initiates and maintains a lock out of the dishwashing mode until the discharge of the reservoir occurs.

[0007] In another aspect, a dishwashing machine includes: a chamber configured to receive dishes, the chamber having at least one injection zone in which liquid can be recirculated from a reservoir to an injection assembly for injecting the liquid onto the dishes. A descaling system is configured to deliver a descaling solution to the reservoir. A controller is configured to operate in at least one dishwashing mode and at least one descaling operation mode. In the descaling operation mode, the descaling system is controlled to perform a descaling operation, wherein the controller: (i) controls the descaling system to deliver the descaling solution into the reservoir and monitors the dishwashing machine to determine whether a reservoir discharge step occurs to discharge the descaling solution from the reservoir, and if not, the controller automatically performs an operation to reduce the acidity of the descaling solution by at least one of the following: (i) causing fresh water to be delivered into the reservoir to dilute the descaling solution in the reservoir or (ii) causing a detergent to be delivered into the reservoir to effect a certain neutralization of the descaling solution in the reservoir.

[0008] Details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram showing an embodiment of a dishwashing machine having a single circulation reservoir;

[0010] Figure 2 A schematic diagram showing an embodiment of a dishwashing machine having two circulation reservoirs; and

[0011] Figure 3 A schematic diagram showing an embodiment of a dishwashing machine having three circulation reservoirs. DETAILED DESCRIPTION

[0012] ReferenceFigure 1 , the ware washing machine 10 includes a housing 12 that defines an internal chamber 12a for receiving the wares to be cleaned. A conveying device 14 (continuous or intermittent) can be operated to transport the wares through the chamber. The chamber includes a spraying zone 18 in which washing liquid (e.g., water and detergent) can be recycled from a reservoir 20 to a spraying assembly 22 for spraying the liquid onto the wares (e.g., by the operation of a pump 24). The spraying assembly can include one or more spraying tubes 22a with associated spraying nozzles. Here, the reservoir 20 includes a discharge opening 26 leading to a discharge path 28 that leads to a discharge outlet 28a of the machine. A rinsing system 30 is also provided downstream of the spraying assembly 22 in the ware conveying direction 16. The rinsing system can include a rinsing spraying assembly 32 having associated spraying tubes 32a, wherein rinsing liquid (e.g., clean water or clean water and rinsing additive) is supplied from a hot water booster 34 via the operation of a rinsing pump 36 (alternatively, pressure-pushed water is supplied through a pipeline to pass through the booster). Clean water can be delivered from a machine clean water input connection 38 to the booster via the operation of a filling valve 40.

[0013] A descaling system is also provided, which includes a descaling chemical source 42 and a descaling pump 44 for selectively supplying the descaling chemical into the booster heater 34 so that a descaling solution (a mixture of water and descaling chemical) can be delivered to the spraying zone 18 and the reservoir 20 through the operation of the pump 36.

[0014] An overflow standpipe 46 is provided in the reservoir and engages with the discharge opening 26 so that liquid in the reservoir rising above the overflow level can travel through the standpipe to the discharge path 28. To completely drain the reservoir 20, the overflow standpipe 46 is raised from the discharge opening 26 (e.g., by manually holding the overflow standpipe) so that the liquid flows directly from the reservoir into the discharge opening 26 and along the path 28.

[0015] A reservoir maintenance filling path 50 can also be provided for delivering water from a machine hot water input connection 52 to the reservoir 20 via the operation of a valve 54.

[0016] The machine includes a controller 100 that is configured to perform various operations of the machine via the operation of machine components. As used herein, the term controller is intended to broadly cover any circuit (e.g., solid state, application specific integrated circuit (ASIC), electronic circuit, combinational logic circuit, field programmable gate array (FPGA)) that performs the control function of the machine or any of its components, a processor (e.g., shared, dedicated, or group, including hardware or software that executes code), software, firmware, and / or other components, or a combination of some or all of the above.

[0017] The controller 100 can be configured with one or more vessel cleaning modes (e.g., spraying wash liquid and rinse liquid on vessels moving through the chamber 12a). The controller 100 is also configured with at least one descaling operation mode. In the descaling operation mode, the descaling system is controlled to perform a descaling operation, where the controller delivers a descaling solution to the reservoir and the injection zone 18 for descaling / demineralizing the surface in the injection zone.

[0018] For example, the descaling solution can be prepared in the booster 34 in a batch process or manner by delivering a descaling chemical to the booster 34 via a pump 44, heating the descaling solution in the booster to a set temperature (e.g., heating to 140°F), and then pumping the descaling solution via a rinse pump 36 to be injected and fill the machine reservoir(s) 20 through the injection tube 32a. The descaling solution fills the reservoir 20 and can be recirculated via a pump 24 to descale the reservoir, the inner wall surface, the reservoir heater 20a, etc. This recirculation can occur continuously or intermittently with downtimes during the descaling cycle over a set time period. In an embodiment, the descaling chemical can alternatively be delivered directly to the reservoir 20 without heating in the booster 34.

[0019] After the descaling solution circulation process is completed, the descaling solution should be drained from the reservoir 20 because it is not desirable to keep the acidic descaling solution in the reservoir for too long a period. For this purpose, the machine can include a user interface 102 (e.g., an HMI with a display screen), and the controller can implement the display of a drain machine alert on the user interface to notify the operator that the reservoir 20 must be drained (e.g., by raising the overflow tube 46, or by manually controlling a drain valve (not shown)). Before the drain machine alert, any descaling solution in the booster 34 can be cleared via the operation of the pump 36 to empty the booster 34 (without adding further descaling chemical to the booster).

[0020] The controller 100 is configured to monitor the machine to determine whether a tank discharge step occurs to discharge the decalcifying solution from the tank 20. In an embodiment, if the tank discharge does not occur, the controller automatically performs an operation to reduce the acidity (increase the pH) of the decalcifying solution in at least one of the following ways: (i) causing fresh water to be delivered into the tank to dilute the solution in the tank (e.g., via the booster 34 and / or directly into the tank via the pipeline 50) or (ii) causing a detergent to be added to the tank to effect a certain neutralization of the liquid in the tank (e.g., via the detergent supply pipeline 56, which is supplied with liquid from the detergent source 57 by the detergent pump 59). The amount of fresh water and / or detergent delivered can be controlled based on the known or expected acidity of the decalcifying solution and the volume in the tank 20, or in the tank, a sensor (e.g., the pH meter 61) can also be used to monitor the changing acidity level. The pump 24 can also be selectively operated as part of this acidity reduction operation.

[0021] In an embodiment, the controller 100 is configured such that during the decalcifying operation, a circulation process is performed in which the decalcifying solution is continuously or intermittently recirculated from the tank through the injection assembly 22, and the controller 100 determines whether a tank discharge operation occurs after the end of the circulation process. The controller can be configured such that if the tank discharge operation does not occur within a set time period (e.g., 10 minutes, 20 minutes, 30 minutes, or 40 minutes) after the end of the circulation process, the controller automatically performs the acidity reduction operation. Thus, in this embodiment, the timeout of the set time period acts as a trigger event for the acidity reduction process. Additionally, the controller can be configured such that after the acidity reduction operation occurs, a shutdown is initiated, thereby preventing operation in the utensil cleaning mode unless and until the tank discharge operation is performed (e.g., even if the machine is powered off and then powered on again). The controller can cause a continuous display of a machine discharge alarm to advise the operator(s) to discharge the tank during the lockout of the utensil cleaning mode.

[0022] In an embodiment, the controller 100 is configured to automatically perform an acidity reduction operation before activating a machine discharge alarm. In such an embodiment, the end of the decalcification cycle / washing cycle timer serves as a trigger event for the acidity reduction process. However, in some implementations, the acidity reduction process may overlap, in whole or in part, with the end portion of the decalcification cycle, in which case the trigger event for the acidity reduction process will be reaching a certain intermediate time point of the decalcification cycle / washing timer (e.g., 90% of the end of the decalcification cycle / washing timer). In either case, after the acidity reduction operation is complete and the decalcification cycle / washing timer ends, the controller activates the machine discharge alarm and a utensil cleaning mode shutdown. The controller may be configured such that if no tank discharge operation occurs within a set period of time (e.g., 10 minutes, 20 minutes, 30 minutes, or 40 minutes) after the machine discharge alarm is activated, the controller powers off the machine. In such an embodiment, the controller is configured such that upon the next power-on of the machine, the controller remains in the decalcification operation mode and restarts the machine discharge alarm and restarts or maintains the utensil cleaning mode shutdown, thereby preventing operation in the utensil cleaning mode unless and until a tank discharge operation is performed.

[0023] In an embodiment, determining whether a tank discharge operation has occurred is based on at least one of the following: (i) monitoring the liquid level in the tank (e.g., via sensor 60), (ii) monitoring the flow of liquid along the discharge path 28 starting from the tank (e.g., via sensor 62), or (iii) monitoring the condition of components associated with the discharge path from the tank (e.g., via sensor 64 that detects the position of the overflow standpipe 46).

[0024] Figure 2 and Figure 3 shows a machine having a plurality of tanks (e.g., Figure 2 the upstream pre-wash tank 120 in Figure 3Machine embodiments 110 and 210 (with upstream pre - wash storage tank 120 and downstream power - wash storage tank 220). Each additional storage tank includes one or more of the corresponding heaters 120a, 220a, overflow standpipes 146, 246, drain paths 128, 228, circulation pumps 124, 224 with associated spray pipes 122a, 222a, and sensors 160, 260 and 161, 261 and 164, 264. To fill the multi - tank machine with a descaling solution, the solution is delivered to the most downstream tank and overflows between the tanks via an overflow path 302. These multi - tank machines can include additional supply paths for delivering descaling chemicals or descaling solution to the tanks without passing through a booster 34. In some embodiments, each tank can also include its own detergent supply line 56. In such a machine, the controller 100 can be configured to monitor and verify that all tanks are properly drained of the descaling solution before a utensil cleaning mode shutdown.

[0025] Exemplary descaling sequence

[0026] In one embodiment, the controller 100 is configured such that in a descaling operation mode, the associated descaling operation or cycle is performed as follows.

[0027] The operator accesses the descaling operation mode by pressing the displayed "Descaling" button on the user interface 102, whether the machine is powered on or off. Alternatively, the descaling operation mode can also be accessed by entering the "Administrator" menu via the user interface 102 and scrolling to the descaling operation cycle.

[0028] Next, the operator is prompted via the user interface 102 to confirm the start of the descaling operation or cycle. To start, the operator selects the "Yes" button and presses the displayed "Confirm" button.

[0029] Next, the operator is notified via a user interface message to clean the filters and baskets associated with the (multiple) machine tanks. The interlock devices associated with one or more doors on the housing (e.g., 10a, 10b, 10c) will open to allow the doors to open for access to the interior of the machine. After the baskets and filters are cleaned, the operator places them back into the machine. Then, the operator selects "Yes" and presses the displayed "Confirm" button to confirm the completion of the filter and basket cleaning.

[0030] Next, the operator is notified via the user interface 102 to drain the machine. Then, the operator pulls the standpipes 46, 146, 246 as needed to drain all the machine tanks. The user interface shows that the machine is draining and can display the progress of the drain (e.g., by using tank level sensors to track the drain). Once the machine has been fully drained, the user interface displays a message indicating to the operator to close the tank drain (e.g., reset the standpipes) and the machine access door 300. Then the door interlock is closed.

[0031] Next, the supercharger fill valve 40 is opened and the decalcification pump 44 is energized to add decalcification chemicals to the supercharger 34, thereby creating a decalcification solution.

[0032] Once the supercharger water level has reached the set point (e.g., detected by sensors or based on known fill times), the rinse pump 36 is energized to deliver the decalcification solution to the tanks (e.g., via the spray arm 32a). During supercharger filling, the decalcification pump 44 is operated so that decalcification solution is periodically added to the supercharger 34 to avoid too high a concentration of decalcification solution in the supercharger tank. The rinse pump operation is delayed / stopped until the supercharger is full, and then the rinse pump 36 operates and empties the supercharger. When emptying the supercharger, the decalcification pump 44 remains closed so that no decalcification solution is added. Once the supercharger 34 is empty, the pump 36 is closed and the supercharger is refilled by opening the valve 40 and periodically operating the decalcification pump 44 to add decalcification chemicals. This process is repeated until all the tanks are considered full (e.g., as detected by tank level sensors).

[0033] Once the controller identifies that all tanks are full, the decalcification wash cycle is initiated and "Decalcification in progress" is displayed on the user interface 102. The wash pumps 24, 124, 224 are operated continuously or intermittently / periodically (regular or irregular dwell times between pump operations) so that the pumps associated with all the tanks present in the machine operate to circulate the decalcification solution for decalcification purposes.

[0034] The length of the decalcification wash cycle is controlled by the decalcification cycle / wash cycle timer. Once the decalcification cycle / wash cycle timer expires or times out, the wash pumps 24, 124, 224 stop and the decalcification dilution operation begins, during which the user interface displays the rinse cycle in the process message. In the decalcification dilution operation, fresh water is added to dilute the decalcification solution in the storage tank, and thus as an acidity reduction process operation, which is triggered at the end of the decalcification cycle / wash cycle timer. Here, the storage tank fill valve 54 is opened to provide a direct flow of fresh water (without decalcification chemicals) into the storage tank(s). The rinse pump 36 is also operated to empty the booster, and the booster fill valve 40 is opened to deliver fresh water into the booster, but the decalcification pump 44 remains closed so that no further decalcification chemicals are added. This ensures the removal of decalcification chemicals from the booster. In some cases, the booster 34 can be cleaned before opening the storage tank fill valve 54. The acidity reduction process is carried out for a specified time according to the decalcification dilution timer. The specified time is preset based on the known volume of the machine storage tank(s) and the known concentration of the decalcification chemicals added.

[0035] After the end of the decalcification dilution timer, a countdown timer is displayed on the user interface along with an operator instruction to drain the machine. If the machine is not drained at the end of the countdown timer, the machine automatically powers off.

[0036] At the next machine startup, an operator notification indicating that the operator should drain the machine is displayed. Detecting the actual draining of all machine storage tanks is necessary to complete the decalcification operation or cycle. This effectively stops the machine's vessel cleaning mode until the storage tank(s) have been drained as the last step of the decalcification operation or cycle.

[0037] As previously discussed, in an alternative embodiment, at the end of the decalcification cycle / wash timer, the storage tank drain message can be implemented first, and if no draining occurs within the specified drain timer, the timeout of the specified drain timer can act as a trigger for the acidity reduction process.

[0038] It should be clearly understood that the above description is for illustrative and exemplary purposes only and not for purposes of limitation, and other changes and modifications are possible.

Claims

1. A dishwasher for washing dishes, the dishwasher comprising: a chamber for receiving a vessel, the chamber having at least one spraying zone in which liquid can be recirculated from a tank to a spraying assembly for spraying the liquid onto the vessel; a decalcification system configured to deliver a decalcification solution to the tank; A controller configured to operate in at least one ware cleaning mode and at least one decalcification mode of operation, wherein in the decalcification mode of operation, the decalcification system is controlled to perform a decalcification cycle, in which the controller: controlling the decalcification system to deliver a decalcification solution into the tank and then circulate the decalcification solution; and An acidity reduction process is performed to reduce the acidity of the decalcification solution by at least one of: (i) causing fresh water to be delivered into the tank to dilute the decalcification solution in the tank or (ii) causing detergent to be delivered into the tank to achieve some neutralization of the decalcification solution in the tank.

2. The dishwasher according to claim 1, wherein: The controller is configured such that the acidity reduction process is performed based on a triggering event.

3. The dishwasher according to claim 2, wherein: The controller is configured such that the triggering event is one of: (i) the end of a decalcification wash / cycle timer or (ii) reaching a midpoint of a decalcification wash / cycle timer.

4. The dishwasher according to claim 3, wherein: The controller is configured such that, following completion of the acidity reduction process, a drain tank message is displayed on a user interface.

5. The dishwasher according to claim 4, wherein: The controller is configured to monitor draining of the tank and to de-energize the machine if the tank is not drained within a specified period of time.

6. The dishwasher according to claim 5, wherein: The controller is configured such that upon the next power-on of the machine, the drain tank message is displayed on the user interface.

7. The dishwasher according to claim 4, wherein: The controller is configured to monitor draining of the tank and prevent operation of the dishwasher in the warewashing mode until draining of the tank is detected.

8. The dishwasher according to claim 7, wherein: The controller monitors the discharge of the tank by one of: (i) monitoring the liquid level in the tank, (ii) monitoring the flow of liquid from the tank along a discharge path, or (iii) monitoring the condition of an overflow standpipe of the tank.

9. The dishwasher according to claim 7, wherein: The tank includes a discharge opening leading to a discharge path, and an overflow standpipe removably engaged with the discharge opening, and draining of the tank requires manual lifting of the overflow standpipe.

10. A dishwasher for washing dishes, the dishwasher comprising: a chamber for receiving the vessels, the chamber having at least one spraying zone in which liquid can be recirculated from the tank to a spraying assembly for spraying the liquid on the vessels, the tank comprising a draining member that must be moved manually in order to drain the tank; a decalcification system configured to deliver a decalcification solution to the tank; A controller configured to operate in at least one ware cleaning mode and at least one decalcification mode of operation, wherein in the decalcification mode of operation, the decalcification system is controlled to perform a decalcification cycle in which the controller: controlling the decalcification system to deliver a decalcification solution into the tank and then circulate the decalcification solution; as well as Monitoring whether draining of the tank occurs after circulation of the descaling solution is complete, and initiating and maintaining shutdown of the warewashing mode until draining of the tank occurs.

11. The dishwasher according to claim 10, wherein: At least one fluid level sensor is associated with the tank, and the controller monitors an output of the fluid level sensor to determine if draining of the tank has occurred.

12. The dishwasher according to claim 10, wherein: The controller is configured such that as part of the decalcification cycle, an acidity reduction process is performed to reduce the acidity of the decalcification solution by at least one of: (i) causing fresh water to be delivered to the tank to dilute the decalcification solution in the tank or (ii) causing detergent to be delivered to the tank to achieve some neutralization of the decalcification solution in the tank.

13. The dishwasher according to claim 12, wherein: The controller is configured such that the acidity reduction process is performed based on a triggering event.

14. The dishwasher according to claim 3, wherein: The controller is configured such that the triggering event is one of: (i) the end of a decalcification wash / cycle timer or (ii) reaching a midpoint of a decalcification wash / cycle timer or (iii) identifying that no draining of the tank has occurred within a set time period.

15. The dishwasher of claim 10, wherein: The discharge component is an overflow standpipe.

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