Patent Description:
Cooking appliances, particularly stoves, ovens, microwaves, steamers, and the like, are provided with steam generator assemblies. Cooking with steam, or at least partially with steam, is generally regarded as a healthier and, oftentimes, faster alternative than many other cooking means. As a result, various steam generator assemblies have become a popular addition to cooking appliances. These steam generator assemblies typically include a water circuit that includes a water reservoir, a steam generator, and a steam outlet. In operation, water from the water reservoir is routed into the steam generator whereat it at least partially turns to steam. The steam is then released through the steam outlet and into a cooking cavity to heat and cook foodstuff within the cooking cavity.

After a cooking cycle, water remaining in the steam generator is pumped back into the water reservoir with a drain pump. The drain pump traditionally generates noise, particularly, when the water level in the steam generation assembly is not accurately estimated. More specifically, when the water is not estimated, the drain pump will continue to operate (e.g., a dry cycle) after the steam generator is empty. These dry cycles are loud and can negatively impact the drain pump over time. Traditional water regulation assemblies utilize methods with set variables that do not account for cycle variations. Cycle variations may become more relevant over operational life as components age and mineral deposits (e.g., limescale) are formed. In addition to changes over operational life, various other conditions can result in cycle variations. These other conditions include voltage variations, environmental temperatures, and part variations. As such, these traditional methods with set variables do not accurately allow water estimation.

Accordingly, the present disclosure provides liquid estimation in a steam generation system that accounts for conditions that impact cycle variations.

Document <CIT> discloses for example a process for restoring the level of water in boilers of steam generating machines according to the available prior art.

The invention relates to a method of controlling a steam generation system according to claim <NUM> and a steam generation system according to claim <NUM>.

According to one aspect of the present disclosure, a method of estimating fluid in a steam generation system includes determining a first steam flow rate of a steam generator. During a present steam cycle, determine a quantity of liquid remaining in the one or more liquid reservoirs by determining a time the steam generator injected steam and multiplying the time by the first steam flow rate. Based on the first steam flow rate, determine a time remaining before the quantity of liquid remaining in the one or more liquid reservoirs is below a threshold and the one or more liquid reservoirs needs to be refilled.

According to another aspect of the present disclosure, a method of estimating fluid in a steam generation system includes determining a first steam flow rate of a steam generator for a present steam cycle. After the present steam cycle, fill the steam generator with a quantity of liquid past a minimum level obtained by a first sensor to a maximum level obtained by a second sensor. Run the steam generator until the quantity of liquid in the steam generator returns to the minimum level. Divide a volume between the minimum level and the maximum level by the time the steam generator was running to determine a second steam flow rate.

According to another aspect, a method of estimating fluid in a steam generation system includes, before a first steam cycle, determining a first drainage flow rate of a drainage pump by measuring a time to reduce a liquid level in a steam generator from a maximum level to a minimum level with input only from the drainage pump. After the first steam cycle, actuate the drainage pump until the liquid level in the steam generator is equal to the minimum level.

The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to liquid (i.e., fluid) estimation in a steam generation system. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

The terms "including," "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "comprises a. " does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Referring initially to <FIG>, reference numeral <NUM> generally designates a steam generation system for a cooking appliance. The steam generation system <NUM> includes at least one liquid reservoir <NUM> (e.g., a single, a pair, three or more liquid reservoirs <NUM>), which may include a liquid-containing body (e.g., water), a manual fill port, a connection to a plumbing system of a building for automatic filling, or a combination thereof. The liquid reservoir <NUM> fluidically connects to a steam generator <NUM> via a first fluid line <NUM>. The steam generator <NUM> heats liquid from the liquid reservoir <NUM> at least partially converting the liquid into a steam. The liquid reservoir <NUM> may include a pressure control unit <NUM> ("PCU"), which may be configured to both generate and reduce a pressure within the liquid reservoir <NUM>. For example, the pressure control unit <NUM> may include a pressure generator, a pressure release valve, and/or a pressure meter to maintain a pressure within the liquid reservoir <NUM> (e.g., an equilibrium with a pressure inside the steam generator <NUM> and/or an atmospheric pressure). The liquid reservoir <NUM> may include a liquid level sensor (not shown) for determining a level of liquid in the liquid reservoir <NUM>. A fill pump <NUM> may be located along the first fluid line <NUM> and controls liquid exiting the liquid reservoir <NUM> and entering the steam generator <NUM>. The liquid reservoir <NUM> also fluidically connects to the steam generator <NUM> via a second fluid line <NUM>. A drainage pump <NUM> may be located along the second fluid line <NUM> and controls liquid exiting the steam generator <NUM> and entering the liquid reservoir <NUM>. A third flow line <NUM> extends from the steam generator <NUM> to a steam output <NUM> into a heating cavity, where food is cooked. It should be appreciated that, in some embodiments, the fill pump <NUM> and the drainage pump <NUM> may be connected to a single fluid line. It should also be appreciated that, in some embodiments, the fill pump <NUM> and the drainage pump <NUM> may be the same component (e.g., a reversible pump). In some embodiments, the steam generation system <NUM> may include a control system <NUM> (<FIG>) for performing the methods as described herein.

With reference now to <FIG>, the steam generator <NUM> may include one or more sensors (e.g., two or more sensors, three or more sensors). In some embodiments, the one or more sensors includes a first fluid level sensor <NUM> associated with a minimum ("MIN") operational level and a second fluid level sensor <NUM> associated with a maximum ("MAX") operational level. The level sensors <NUM>, <NUM> are visible or otherwise generate (e.g., via the control system <NUM>) a notification to a user of the fluid level. Accordingly, the user may obtain knowledge from the level sensors <NUM>, <NUM> that the steam generator <NUM> is either at MIN or MAX. During a cooking cycle, liquid is introduced to the steam generator <NUM> and maintained between the MAX and MIN levels where it is heated, partially becoming steam that exits the steam output <NUM>. When the cooking cycle is complete, the drainage pump <NUM> substantially empties ("<NUM> level") the steam generator <NUM> and liquid from related components of the steam generation system <NUM> (e.g., the first fluid line <NUM> and the second fluid line <NUM>), and reintroduces substantially all the liquid from the steam generation system <NUM> back into the liquid reservoir <NUM>. In other words, at empty or <NUM> level, while certain components of the steam generation system may be slightly coated in liquid, substantially all the liquid has been removed by operation of the drainage pump <NUM>. The fill pump <NUM> provides a fill flow rate FRfp, the drainage pump <NUM> provides a drainage flow rate FRdp, and the steam generator <NUM> provides a steam flow rate FRboiler.

<FIG> schematically illustrates the control system <NUM>. The control system <NUM> may include an electronic control unit (ECU) <NUM>. The ECU <NUM> may include a processor <NUM> and a memory <NUM>. The processor <NUM> may include any suitable processor <NUM>. Additionally, or alternatively, the ECU <NUM> may include any suitable number of processors, in addition to or other than the processor <NUM>. The memory <NUM> may comprise a single disk or a plurality of disks (e.g., hard drives) and includes a storage management module that manages one or more partitions within the memory <NUM>. In some embodiments, memory <NUM> may include flash memory, semiconductor (solid-state) memory, or the like. The memory <NUM> may include Random Access Memory (RAM), a Read-Only Memory (ROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), or a combination thereof. The memory <NUM> may include instructions that, when executed by the processor <NUM>, cause the processor <NUM> to, at least, perform the functions associated with the components of the control system <NUM>. The fill pump <NUM>, the drainage pump <NUM>, and an alarm <NUM> (e.g., a user interface on a cooking appliance, a light on a cooking appliance, a connected mobile computing device, and/or the like) may, therefore, be controlled and/or receive instructions from the ECU <NUM>. The memory <NUM> may, therefore, include software <NUM>, obtained flow rates <NUM> (i.e., the fill flow rate FRfp, the drainage flow rate FRdp, and the steam flow rate FRboiler), volume data <NUM> (i.e., a volume capability of the liquid reservoir <NUM>, an aggregate of more than one liquid reservoir <NUM>, a volume between MAX and MIN levels of the steam generator <NUM>), parameter data <NUM> (i.e., a set number of steam cycles before completing any of the below method steps, supply voltage, supply frequency), and user preference data <NUM> (e.g., a selected steam cycle setting). The control system <NUM> may be configured to perform the method steps as described herein.

With reference now to <FIG>, the steam generation system <NUM> includes a liquid estimation method <NUM>. The liquid estimation method <NUM> improves upon the traditional methods by calculating the liquid level at or between each steam cycle or a predetermined number of steam cycles (e.g., after zero steam cycles, after each steam cycle, every five steam cycles, every ten steam cycles, and/or the like) to determine a liquid usage rate and estimate when the liquid reservoir <NUM> (or more than one liquid reservoir <NUM>) will need to be filled. The liquid estimation method <NUM> also can be utilized to determine an amount of liquid within the steam generator <NUM> and the drainage flow rate FRdp to minimize dry cycle duration of the drainage pump <NUM> once the steam generation system <NUM> has completed the steam cycle. The liquid estimation method <NUM> includes several steps that occur at the beginning of a steam cycle and additional steps that occur during the steam cycle. Each of these steps may occur (e.g., via parameter data <NUM>), after an equal predetermined number of steam cycles, or after different predetermined numbers of steam cycles, which are generically referred to as a first, second, third, or fourth predetermined number of steam cycles. These different steam cycles may also be generally referred to as a present steam cycle, a subsequent steam cycle that occurs after the present steam cycle, and an additional steam cycle (i.e., an additionally requested steam cycle) that occurs after the subsequent steam cycle. In other words, some steps may occur during each steam cycle and other steps may occur after more than one steam cycle (e.g., two, three, or more steam cycles). In some embodiments, the liquid estimation method <NUM> may be facilitated by the control system <NUM>.

The liquid estimation method <NUM> may be reoccurring such that a first drainage flow rate FRdp can be obtained for a present steam cycle and, after a second predetermined number of cycles, a second flow drainage flow rate FRdp can be obtained for a subsequent steam cycle that is different than the first drainage flow rate FRdp. Similarly, a first fill flow rate FRfp can be obtained for a present steam cycle and, after a second predetermined number of cycles, a second flow fill flow rate FRfp can be obtained for a subsequent steam cycle that is different than the first fill flow rate FRfp. Likewise, a first steam flow rate FRboiler can be obtained for a present steam cycle and, after a second predetermined number of cycles, a second steam flow rate FRboiler can be obtained for a subsequent steam cycle that is different than the first steam flow rate FRboiler. These differences in flow rates may be the result of environmental conditions and/or aging components of the steam generation system <NUM>. It should also be appreciated that a length of time (e.g., a week, a month, a year) may be used alternatively or in conjunction with the predetermined number of steam cycles.

With reference specifically to <FIG>, steps <NUM> - <NUM> generally occur at the beginning of a steam cycle. At step <NUM>, the liquid estimation method <NUM> includes, before each or a predetermined number of steam cycles, adding fluid to the steam generator <NUM> with the fill pump <NUM> until the first liquid level sensor <NUM> determines that the liquid is at MIN. For example, the processor <NUM> may be configured to actuate the fill pump <NUM> until the liquid level reaches MIN and timing the operation. At step <NUM>, the liquid estimation method <NUM> includes continuing to add fluid with the fill pump <NUM> until the second liquid level sensor <NUM> determines that the liquid level is at MAX. For example, the processor <NUM> may be configured to further actuate the fill pump <NUM> until the liquid level reaches MAX while timing the operation. During steps <NUM> and <NUM>, only the fill pump <NUM> is actuated to move liquid from the at least one liquid reservoir <NUM> to the steam generator <NUM>. For example, step <NUM> may be completed (e.g., by the processor <NUM>) in accordance with Eq. (<NUM>) below: <MAT> wherein, tmin is equal to zero and tmax is equal to the time in seconds to obtain the fluid level MAX, starting from fluid level MIN, with input only from the fill pump <NUM> and the volume of liquid between Volumemax and Volumemin is known (e.g., in ml). Thus, the fill flow rate FRfp, at any time of the operational life of the cooking appliance, can be determined. At step <NUM>, the liquid estimation method <NUM> may include determining a liquid quantity in the steam generation system <NUM> between empty or <NUM> level and MIN in the steam generator <NUM> based on the time (which may be obtained from step <NUM>) it takes the first fluid level sensor <NUM> to read MIN from empty and multiplying that time by the fill flow rate FRfp (which may be obtained from step <NUM>) to estimate a volume between MIN and <NUM> level (e.g., liquid remaining in the first fluid line <NUM>, the second fluid line <NUM>, the steam generator <NUM>, and other components of the steam generation system <NUM>). For example, the processor <NUM> may be configured to actuate the fill pump <NUM> until the liquid level reaches MIN from <NUM> level while timing the operation.

At step <NUM>, the liquid estimation method <NUM> includes measuring the drainage flow rate FRdp of the drainage pump <NUM>. As explained in the background section, the drainage flow rate FRdp may change over time based on any number of environmental or operational factors. By periodically measuring the drainage flow rate FRdp, dry cycle duration of the pump can be minimized. Step <NUM> includes actuating the drainage pump <NUM> and determining how long it takes the liquid level in the steam generator <NUM> to reduce from MAX to MIN (e.g., via the first liquid level sensor <NUM>). For example, the processor <NUM> may be configured to actuate the drainage pump <NUM> until the liquid level reaches MIN while timing the operation. During step <NUM>, only the drainage pump <NUM> is actuated to move liquid from the steam generator <NUM> to the at least one liquid reservoir <NUM>. For example, step <NUM> may be completed in accordance with Eq. (<NUM>) below: <MAT> where tmin is equal to zero and tmax is equal to the time in seconds to obtain the fluid level MIN from fluid level MAX with input only from the drainage pump <NUM> and the volume of liquid between Volumemax and Volumemin is known (e.g., in ml). Thus, the drainage flow rate FRdp at any time of the operational life of the cooking appliance can be determined. As such, because <NUM> level is not a measurable quantity, the differences between <NUM> level and MIN or MAX can be estimated to limit dry cycle duration in conjunction with the drainage flow rate FRdp at any time of the operational life. At step <NUM>, the liquid estimation method <NUM> includes refilling the liquid in the steam generator <NUM> until the second liquid level sensor <NUM> determines the liquid level is again at MAX. For example, the processor <NUM> may be configured to actuate the fill pump <NUM> until the liquid level reaches MAX.

With continued reference to <FIG>, steps <NUM> - <NUM> generally occur during the steam cycle. At step <NUM>, the liquid estimation method <NUM> includes, during a steam cycle, measuring the steam flow rate FRboiler of the steam generator <NUM> by measuring how long it takes the liquid level in the steam generator <NUM> to reduce from MAX to MIN (e.g., with the first and second fluid level sensors <NUM>, <NUM>) without input from the fill pump <NUM> or the drainage pump <NUM>. For example, the processor <NUM> may be configured to actuate the steam generator <NUM> until the liquid level reaches MIN and timing the operation. The steam flow rate FRboiler of the steam generator <NUM> is the rate at which liquid is heated into steam and dissipated into the heating cavity. For example, step <NUM> may be completed in accordance with Eq. (<NUM>) below: <MAT> where tboiler is equal to the time in seconds the steam generator <NUM> is actuated to obtain the fluid level MIN with input only from the steam generator <NUM> and the volume of liquid between Volumemax and Volumemin is known (e.g., in ml). Thus, the steam flow rate FRboiler at any time of the operational life of the cooking appliance can be determined.

Based on steps <NUM> - <NUM>, the liquid estimation method <NUM> includes, at step <NUM>, determining a liquid level in the one or more liquid reservoirs <NUM>. Step <NUM> includes referencing a known starting amount in the one or more liquid reservoirs <NUM> before the steam cycle, for example, when the one or more liquid reservoirs <NUM> are full (the Waterreservoir (t0)) and subtracting the steam flow rate FRboiler multiplied by the time (in seconds) that the steam generator <NUM> was running. The processor <NUM> may be configured to subtract the steam flow rate FRboiler multiplied by the time (in seconds) that the steam generator <NUM> was running from a known liquid quantity in the one or more liquid reservoirs <NUM>. For example, step <NUM> may be completed in accordance with Eq. (<NUM>) below: <MAT> where Waterreservoir at (tEND) is equal to the liquid quantity in the one or more liquid reservoirs <NUM>. Waterreservoir at (tEND) will change based on known quantities obtained from the previous steps, for example, after the steam generator <NUM> is on and the steam flow rate FRboiler continues for a number of seconds (ton). Waterboilert_current is an estimated quantity of liquid in the steam generator <NUM>, which may be determined based on a total quantity of liquid reduction based on the steam flow rate FRboiler from MAX, a liquid increase based on the fill flow rate FRfp from MIN, or by being at either MIN or MAX via the level sensors <NUM>, <NUM>. Step <NUM>, may, alternatively, include measuring an ending quantity of liquid in the one or more liquid reservoirs <NUM>, once all the liquid in the steam generation system <NUM> is returned to the one or more liquid reservoirs <NUM>. The alternative estimation would follow Eq. (<NUM>) above, but would not include Waterboilert_current as part of the calculation.

Based on steps <NUM> - <NUM>, the time at which the one or more liquid reservoirs <NUM> needs to be refilled can be determined at step <NUM>. At step <NUM>, the liquid estimation method <NUM> includes determining (e.g., the processor <NUM> may be configured to determine) how much time is remaining before refill requirements by dividing the amount of liquid in the one or more liquid reservoirs <NUM> (e.g., based on step <NUM>) by the steam flow rate FRboiler (step <NUM>), if the steam flow rate FRboiler for a selected steam cycle is constant, multiplied by how much longer the steam cycle has to run within a steam cycle. In other embodiments, the steam flow rate FRboiler for a selected steam cycle may not be constant (e.g., one or more rates) and the steam flow rate FRboiler can be averaged or otherwise determined based on the time (t) that each steam flow rate FRboiler is occurring in the selected steam cycle. Regardless, the resulting number may then be multiplied by <NUM>/<NUM> to provide a time in minutes before the one or more liquid reservoirs <NUM> needs to be refilled. For example, step <NUM> may be completed in accordance with Eq. (<NUM>) below: <MAT> where the time in minutes before the one or more liquid reservoirs <NUM> needs to be refilled (Tremaining) is determined by multiplying the steam flow rate FRboiler (step <NUM>) by the remaining steam cycle requirement (dutyboiler%). This resulting number may then be multiplied by <NUM>/<NUM> to provide Tremaining. The Watersystemt_current is equal to the liquid level currently in the one or more liquid reservoirs <NUM> and the Waterboilert_current is equal to liquid level currently in the steam generator, both obtained in step <NUM> and/or Eq. <NUM>.

With continued reference to <FIG>, steps <NUM> and <NUM> generally occur during the steam cycle and step <NUM> generally occurs after the steam cycle. At step <NUM>, if the one or more liquid reservoirs <NUM> need to be refilled, then the alarm <NUM> may generate a notification (e.g., the processor <NUM> may be configured to generate the notification) to the user, a service/maintenance provider, and/or actuating an auto-refill process (e.g., by the processor <NUM>) where the auto-refill process is stopped upon completion (e.g., when the one or more liquid reservoirs <NUM> are full). Based on how much longer the steam cycle has to run and the Tremaining, step <NUM> may further include, at step <NUM>, generating a warning (e.g., requesting manual refill or request approval to begin auto-refilling) or automatically (e.g., without user approval) starting the auto-refill process before the duty cycle is complete. For example, the processor <NUM> may be configured to generate the warning or automatically refill the steam generation system <NUM>.

At step <NUM>, the liquid estimation method <NUM> may include (e.g., the processor may be configured to), after a steam cycle, emptying the steam generator <NUM>. Step <NUM> includes actuating the drainage pump <NUM> and, after a MIN fluid level is reached, multiplying the drainage flow rate FRdp by a time until the volume between MIN and empty (e.g., as obtained in step <NUM>) is reached.

With reference now to <FIG>, the present disclosure may utilize data obtained from liquid estimation method <NUM> to make certain recommendations in a system management method <NUM>. For example, the system management method <NUM> may include (e.g., the processor may be configured to), at step <NUM>, determining a difference (e.g., lower or higher) in fill flow rate FRfp beyond a threshold (e.g., in association with sequentially repeating steps <NUM>-<NUM> to obtain a first fill flow rate FRfp and a second fill flow rate FRfp). At step <NUM>, the system management method <NUM> may include (e.g., the processor may be configured to) generating a notification, to a user and/or a service/maintenance provider, that the steam generation system needs servicing (e.g., maintenance, descaling, etc.). For example, the fill pump specifically needs to be replaced because of a loss of efficiency. The system management method <NUM> may include (e.g., the processor may be configured to), at step <NUM>, determining a difference (e.g., lower or higher) in drainage flow rate FRdp beyond the threshold (e.g., in association with sequentially repeating step <NUM> to obtain a first drainage flow rate FRdp and a second drainage flow rate FRdp). At step <NUM>, the system management method <NUM> may include (e.g., the processor may be configured to) generating a notification, to a user and/or a service/maintenance provider, that the steam generation system needs servicing (e.g., maintenance, descaling, etc.). For example, the drainage pump specifically needs to be replaced because of a loss of efficiency. The system management method <NUM> may (e.g., the processor may be configured to), at step <NUM>, determine a difference (e.g., lower or higher) in steam flow rate FRboiler beyond the threshold (e.g., in association with sequentially repeating step <NUM> to obtain a first steam flow rate FRboiler and a second steam flow rate FRboiler). At step <NUM>, the system management method <NUM> may (e.g., the processor may be configured to) generate a notification, to a user and/or a service/maintenance provider, that the steam generation system needs servicing (e.g., maintenance, descaling, etc.). For example, the steam generator specifically needs to be replaced because of a loss of efficiency.

The invention disclosed herein is further summarized in the following paragraphs and is further characterized by combinations of any and all of the various aspects described therein.

According to another aspect, a method includes, before a present steam cycle, determining a starting quantity of liquid in one or more liquid reservoirs.

According to another aspect, a method includes obtaining a usage requirement by multiplying a first steam flow rate by at least one of a remaining steam cycle requirement of a present steam cycle or a subsequent steam cycle requirement of a subsequent steam cycle. Comparing a usage requirement with a quantity of liquid remaining in one or more liquid reservoirs.

According to still another aspect, a method includes, after a present steam cycle, determining a second steam flow rate of a steam generator.

According to another aspect, a first steam flow rate is different than a second steam flow rate.

According to yet another aspect, a method includes, during a subsequent steam cycle, determining a time remaining before a quantity of liquid remaining in one or more liquid reservoirs is below a threshold and the one or more liquid reservoirs needs to be refilled based on a second steam flow rate.

According to still another aspect, a method includes comparing a first steam flow rate to a second steam flow rate and upon a determination that the second steam flow rate is different (e.g., lower or higher) than the first steam flow rate by a threshold amount, generating a notification.

According to another aspect, the notification specifically addresses a steam generator efficiency.

According to yet another aspect, the one or more fluid reservoirs includes at least two fluid reservoirs.

According to still another aspect, a method includes filling a steam generator with a quantity of liquid past a minimum level obtained by a first sensor to a maximum level obtained by a second sensor. Running the steam generator at a first steam flow rate until a quantity of liquid in the steam generator returns to the minimum level. Dividing a volume between the minimum level and the maximum level by a time the steam generator was running.

According to still another aspect, a method includes, before a subsequent steam cycle, obtaining a starting quantity of liquid in one or more liquid reservoirs. During the subsequent steam cycle, determining a quantity of liquid remaining in one or more liquid reservoirs by determining a time a steam generator injected steam and multiplying the time by a second steam flow rate.

According to yet another aspect, a method includes, based on a second steam flow rate, determining a time remaining before a quantity of liquid remaining in one or more liquid reservoirs is below a threshold and one or more liquid reservoirs needs to be refilled.

According to still another aspect, a method includes, after the subsequent steam cycle, generating a notification if an additionally requested steam cycle will not be completed prior to when one or more liquid reservoirs need to be refilled.

According to yet another aspect, a first steam flow rate is different than a second steam flow rate.

According to yet another aspect, a method includes continuing to actuate the drainage pump for a period of time until the liquid level is empty wherein substantially all of the liquid in the steam generation system is located in one or more liquid reservoirs based on the first drainage flow rate.

According to yet another aspect, a method includes, after a first steam cycle but before a second steam cycle, determining a second drainage flow rate of a drainage pump by measuring a second time to reduce a liquid level in a steam generator from a maximum level to a minimum level with input only from the drainage pump. After a second steam cycle, actuating the drainage pump until the liquid level in the steam generator is equal to the minimum level.

According to yet another aspect, a method includes continuing to actuate the drainage pump for a second period of time until the liquid level is empty based on the second drainage flow rate and where the first drainage flow rate is different than a second drainage flow rate.

According to still another aspect, a method includes comparing a first drainage flow rate and a second drainage flow rate. Upon a determination that the second drainage flow rate is different (e.g., lower or higher) than the first drainage flow rate by a threshold amount, generating a notification.

According to yet another aspect, the notification specifically addresses a drainage pump efficiency.

According to still another aspect, a method incudes, with a fill pump, filling a liquid level in a steam generator to a maximum level, turning the fill pump off, and, with a drainage pump, reducing the liquid level in the steam generator to a minimum level.

According to yet another aspect, a method includes determining a fill flow rate of a fill pump by determining a time to fill a steam generator between a minimum level and a maximum level and dividing the time by a volume between the minimum level and the maximum level. Starting at empty, filling the steam generator for a period of time to reach the minimum level with input only from the fill pump and multiplying the period of time by the fill flow rate to obtain a volume between the minimum level and empty.

According to yet another aspect, a method includes, before the first steam cycle, determining a first fill flow rate of the fill pump by determining a time to fill the steam generator between the minimum level and the maximum level and dividing the time by a volume between the minimum level and the maximum level. Before a second steam cycle, determining a second fill flow rate of the fill pump by determining a time to fill the steam generator between the minimum level and the maximum level and dividing the time by a volume between the minimum level and the maximum level. The method further includes comparing the first fill flow rate and the second fill flow rate and upon a determination that the second fill flow rate is different than the first fill flow rate by a threshold amount, generating a notification.

Claim 1:
A method (<NUM>) of controlling a steam generation system (<NUM>), in particular a steam generation system (<NUM>) of a cooking appliance, the steam generation system (<NUM>) including one or more liquid reservoirs (<NUM>), a steam generator (<NUM>) and a steam output (<NUM>), the one or more liquid reservoirs (<NUM>) being fluidically connected to the steam generator (<NUM>), the steam generator (<NUM>) being configured for converting liquid from the one or more liquid reservoirs (<NUM>) into steam in particular during a steam cycle, a steam line (<NUM>) extending from the steam generator (<NUM>) to the steam output (<NUM>), characterized in that the
method (<NUM>) comprises the steps of:
during a present steam cycle, determining an injection time in which steam is injected by the steam generator (<NUM>) and/or by the steam output (<NUM>);
multiplying the injection time by a predetermined steam flow rate of the steam generator (<NUM>);
based on the predetermined steam flow rate of the steam generator (<NUM>) and on the injection time, determining a quantity of liquid remaining in the one or more liquid reservoirs (<NUM>); and
based on the predetermined steam flow rate of the steam generator (<NUM>) and on the quantity of liquid remaining in the one or more liquid reservoirs (<NUM>), determining a remaining time.