A FRYER AND A METHOD FOR CONTROLLING THE OPERATION OF THE FRYER DEPENDING ON THE CONDITION OF A FRYING LIQUID

FIELD OF THE INVENTION

The present invention is enclosed in the area of monitoring and control of the degradation of frying liquids in a fryer, the frying liquid typically consisting of a frying oil or fat, for instance an oil such as sunflower oil .

Such method is more frequently applicable to industrial fryers, which operate daily and for several consecutive hours, but it also applies to home solutions.

PRIOR ART

Solutions exist in the art where, such as the case of patent application US6600S06, which discloses the control of the operation of a frying system based on a determination of the concentration of polar compounds of the oil contained in the fryer.

Such solution, which is the most highly developed known prior art, lacks several enhancements and still requires a high maintenance from a human user, namely nor providing an automatic operation, and in particular embedded automatic features which the human user is not able to implement.

The present solution innovatively overcomes such issues. SUMMARY OF THE INVENTION

It is therefore an object of the present invention a method for controlling the operation of a fryer comprising a heatable vat depending on the condition of a frying liquid contained in such vat, the frying liquid preferably consisting of an oil or of a frying fat, which comprises the following steps:

- determining the condition of the frying liquid (110) based on the concentration of polar compounds present in the frying liquid, by means of a sensor provided in the fryer (111),

- compare the determined concentration with a predefined maximum value (120), and

- perform a further action on the fryer depending on said comparison (130),

wherein said determination of the concentration of polar compounds is performed only after a predefined minimum temperature has been reached by the frying liquid, the predefined minimum temperature being obtained by means of the action of a heating element provided in the fryer. The method of the present invention therefore provides that the frying liquid is only evaluated when the temperature is of a minimum value, defined as the predefined minimum temperature. Such provides for a more accurate determination of the concentration of polar compounds, thereby leading to the failure to identify a case in which the determined concentration is still below the predefined maximum value due very low temperature of the liquid. The fryer comprises a heating element which heats a frying liquid contained in the vat, thereby providing for the frying of elements which are subsequently placed into the frying liquid. Moreover, the fryer may contain other elements, known in the art, such as a thermostat which allows to control the heating element, so that the temperature of the frying liquid is maintained between a lower value and a higher value. Such control may therefore be performed automatically and continuously. The object of the present invention is related with the monitoring of the thermoxidation of frying oils in the vat of fryers, using such monitoring to automatically control the operation of the fryer, and thereby avoiding frequent situations in the area, including the replacement of frying liquid which is still in good condition or the usage of oil which is no longer in good condition. The good or bad condition is defined as regards the comparison of the concentration of polar compounds determined for a frying liquid with a predefined value, considered as a threshold of the concentration of polar compounds for considering a frying liquid good or bad for usage.

Moreover, and typically, for a common frying oil, the optimal temperature for determining the concentration of polar compounds, the predefined minimum temperature, is between 150 °C and 180 °C.

The further action of the third step of the method may comprise one or more of the following actions, where the determined concentration is higher than the predefined maximum value (131):

- stopping or reducing the heating of the frying liquid contained in the fryer, preferably by means of regulation of the action of the heating element provided in the fryer,

- initiation of automatic filtering, the automatic filtering comprising the passage of the frying liquid through a filter,

- initiation of automatic exchange of the frying liquid, the automatic exchange of frying liquid preferably being performed by the complete removal of used frying liquid and the subsequent addition of new frying liquid, and/or

- the emission of one or more messages to be received in a monitoring device, preferably a remote monitoring device, wherein each message may comprise information on the result on the comparison, the initiation of automatic filtering, automatic exchange of the frying liquid, stoppage or reduction of the heating of the frying liquid and/or the level of frying liquid in the vat. Each of such actions provides for additional advantages with respect to prior art, the combination of which also provides for additional technical benefits. For instance, the method may provide that the automatic exchange of the frying liquid is only performed after i) the initiation of automatic filtering and ii) a subsequent heating cycle have been previously provided. Such advantages are further explained below.

It is also an object of the present invention a fryer comprising a heatable vat, configured to be controlled depending on the condition of a frying liquid contained in such vat, the frying liquid preferably consisting of an oil or of a frying fat. The fryer, or any of the means or elements it comprises, are configured to implement the method of the present invention, in any of the disclosed embodiments.

DESCRIPTION OF FIGURES

Figure 1 - representation of an embodiment of the method of the present invention, referring to the main steps of the method, including the determination of the condition of the frying liquid (110), the comparison of with a predefined maximum value (120) and performing a further action (130).

Figure 2 - specifies the embodiment of Fig. 1, in particular referring to the sub-steps of the determination of the condition of the frying liquid (110), which is i) based on the concentration of polar compounds present in the frying liquid, and ii) by means of a sensor provided in the fryer (111).

Figure 3 - specifies the embodiment of Fig. 1, in particular referring to possible implementations of the further action of the third step (130), including i) stopping or reducing the heating of the frying liquid contained in the fryer, ii) initiation of automatic filtering, iii) initiation of automatic exchange of the frying liquid and/or iv) the emission of one or more messages (131). Figure 4 - it refers to an inventive concept of the method of the present invention, related to the automatic filtering functionality, which under the detection of a condition leading to further action of automatic filtering (411), leads to passing the frying liquid through a filter (41S) and subsequently continue the frying with the filtered frying liquid (414). Preferably, the filtering is only performed after the temperature of the frying liquid in vat is less than a predefined minimum value (412).

DETAILED DESCRIPTION

The more general and advantageous configurations of the present invention are described in the Summary of the invention. Such configurations are detailed below in accordance with other advantageous and/or preferred embodiments of implementation of the present invention.

It is also an object of the present invention a system for the control of one or more fryers, the system comprising at least one fryer according to claim and a monitoring device, the monitoring device preferably comprising a mobile device, such as a smartphone. Such system may further comprise a control device, wherein:

- the control device is configured to issue one or more control commands directed to the at least one fryer, the control commands being adapted to alter at least one parameter of each fryer, such parameter being one or more of the following: i. a value of the predefined minimum temperature,

ii. the predefined maximum value of concentration,

iii. a value of the predefined minimum level of frying liquid,

iv. a value of the predefined time period, and

- the fryer being further configured to alter said parameter upon the receipt of one of said control commands, and

preferably, the monitoring device consisting of the control device. ln a preferred embodiment of the method of the present invention, said further action (131), where the determined concentration is higher than the predefined maximum value, comprises stopping or reducing the heating of the frying liquid contained in the fryer, preferably by means of regulation of the action of the heating element provided in the fryer. Thus, the method of the present invention provides for automatic stop or reduction, preferably a stop, of the heating of the liquid, avoiding that the concentration of polar compounds rises even more and that the user is forced to change the frying liquid to a new one, which provides a lower concentration of polar compounds.

It may be further provided that the method of the present invention includes a range of warning, the range of warning corresponding to a range of values of determined concentration which are below the predefined maximum value but above a predefined warning value, the predefined warning value being lower than the predefined maximum value. It therefore provides for an anticipation of an upcoming undesirable condition of the frying liquid. Moreover, the automatic filtering, measure of frying liquid in the vat and/or automatic oil exchange may be initiated upon a determination of a concentration within the referred range of warning. Preferably, automatic filtering is initiated as a consequence of a determined concentration within the range of warning, preferably more than one heating cycle after.

In an advantageous embodiment of the method of the present invention, combinable with any above described, it further comprises the determination of the presence of frying liquid in the fryer, preferably by means of a level probe, said determination of the concentration of polar compounds being dependent on the presence of a predefined minimum level of frying liquid. It therefore allows to determine whether the optimal conditions are gathered for frying, which includes the presence of a minimum quantity of frying liquid. ln another inventive aspect of the method of the present invention, it further comprises identifying one or more of the following:

- heating cycles, a heating cycle being defined by a cycle of continuous heating and subsequent continuous cooling (for instance, during a continuous meal preparation period, which may correspond, in a restaurant, to lunch or dinner, for example),

- frying liquid exchange time cycle, defined as the period of time from the identification of a new frying liquid to a situation of determined concentration above the predefined maximum value and/or within the range of warning

- duration and number of continuous cooking in the vat, a continuous cooking corresponding to the continuous cooking of a set of elements - for instance fries -, the end of such continuous cooking being identified by means of a variation in the measured temperature above 10 °C while the heating element is maintained on,

- power consumption of the fryer within a predefined time period, preferably in respect of a heating cycle, duration of continuous cooking in the vat or a frying liquid exchange time cycle.

Wherein such identified parameters may also be included in the referred of one or more messages to be received in a monitoring device, for instance to be emitted on a daily basis.

It therefore provides the monitoring of the performance of the frying liquid, determining how many heating cycles it enables, as well as a correlation with the duration of continuous heating, which also affects the degradation of the liquid and consequent rise of the concentration of polar compounds. It therefore allows that the performance - in terms of number of heating cycles and duration of continuous heating - of a certain frying liquid is determined. Thus, and preferably, the method further comprises the identification of the frying liquid contained in the vat, and thereby associating one or more performance indicators with such frying liquid, the performance indicators comprising the number of heating cycles until a condition of determined concentration above a predefined maximum value is determined.

The identification of the frying liquid may include an input of a human user indicating such identification, but also the provision of reading means in the fryer, such as an optical code reading unit, able to read a bar or QR code provided in the package of the frying liquid, or even a digital camera, able to take a picture which identifies the frying liquid.

In another inventive aspect of the method of the present invention, the comparison of a presently determined concentration with one or more previously obtained values is performed, and where it results a reduction of at least a predefined minimum percentage from such comparison, a change of frying liquid is detected. Thus, a history monitoring is performed, namely allowing to determine whether a change in the frying liquid, which is related to a drastic reduction in the determined concentration - measured by means of a reduction of at least a predefined minimum percentage.

In another advantageous embodiment of the method of the present invention, said further action (131), where the determined concentration is higher than the predefined maximum value or within the range of warning, comprises the initiation of automatic filtering (411), the automatic filtering comprising the passage of the frying liquid through a filter (413). Thus, the life of the frying liquid is automatically extended, by means of the passage of the liquid through a circuit which reduces the presence of polar compounds, for instance by passing the liquid through a filter, the filter preferably comprising a net. The liquid can then be reused (414), until a new condition of concentration above the predefined maximum value is determined.

Furthermore, and in order to avoid that the operation of the fryer is stopped to initiate the filtering of the liquid - a situation which could be very problematic in business solutions, such as in an industrial fryer used in a restaurant - the initiation of the automatic filtering is performed only after the temperature of the frying liquid contained in the vat is less than a predefined minimum value (for instance, of 50 °C) (412), preferably further comprising an automatic prompting of an user to initiate the automatic filtering. Such prompting may include, for instance, requesting an input from the user by means of input means such as a button or a touch screen.

In another inventive aspect of the method of the present invention, said further action (131), where the determined concentration is higher than the predefined maximum value, comprises the initiation of automatic exchange of the frying liquid, the automatic exchange of frying liquid preferably being performed by the complete removal of used frying liquid and the subsequent addition of new frying liquid. Thus, a frying liquid which is no longer in conditions to be used, is automatically replaced by a new frying liquid, in a good condition as regards polar compounds. As in the case of the automatic filtering, the automatic exchange may also be performed only after the temperature of the frying liquid contained in the vat is less than a predefined minimum value, preferably further comprising an automatic prompting of a user.

In a further inventive aspect, and as previously referred, the automatic exchange of frying liquid may be performed only after one or more automatic filtering of a same frying liquid has been previously performed, and preferably after at least one heating cycle has been performed after an automatic filtering. Thus, the frying liquid is exchanged only after at least one try to reuse it has been made. Such provides additional advantages, since the reduction of used frying liquid has not only an environmental impact but also a costs impact.

So as to better continuously monitor the condition of the frying liquid, the determination of the concentration of polar compounds is performed periodically, the frequency of such determination being dependent on the concentration of polar compounds, whereby a higher concentration results in a higher frequency. Thus, and knowing that the concentration of polar compounds can rise faster for higher (although still acceptable) conditions, the frequency of measurement may be increased if such concentration is higher.

In yet another aspect of the method of the present invention, said further action (131), where the determined concentration is higher than the predefined maximum value, comprises the emission of one or more messages to be received in a monitoring device, each message being in respect of one or more of the following:

- the determination that the concentration of polar compounds is higher than the predefined maximum value,

- the number of heating cycles of the present frying liquid,

- the initiation and/or end of an automatic filtering,

- the initiation and/or end of an automatic exchange,

- power consumption within the period of one day,

- duration and number of continuous cooking in the vat.

Such emission of one or more messages allows for a remote monitoring of the performance of the frying liquid, and in particular to identify relevant actions of the fryer, such as the initiation and/or end of an automatic filtering and the initiation and/or end of an automatic exchange.

Moreover, such performance indicators may also be sent to another device when the concentration of polar compounds is lower than the predefined maximum value, in order to provide a remote continuous monitoring.

As previously referred, it is also an object of the present invention a fryer comprising a heatable vat, configured to be controlled depending on the condition of a frying liquid contained in such vat, the frying liquid preferably consisting of an oil or of a frying fat, the fryer comprising: - means for determining the temperature of the frying liquid contained in the vat,

- means for determining the condition of the frying liquid based on the concentration of polar compounds in such frying liquid, and

- a heating element,

wherein the controllable fryer and/or any of the means or elements/units it comprises are configured to implement the method of the present invention, in any of the described embodiments.

Moreover, and in a preferred embodiment, the fryer further comprises one or more of the following components:

- a level probe,

- means for identification of the frying liquid contained in the vat,

- an automatic filtering unit, preferably comprising a circuit which comprises a filter, the automatic filtering being connected to the vat,

- automatic exchange of the frying liquid unit, being preferably connected to an outlet and an inlet formed in the vat,

- means for the issue of one or more messages, such means preferably comprising a communication controller suitable to communicate under a wireless protocol such as a local area wireless network or a cellular network,

specifically the fryer and/or any of the means or elements/units it comprises being configured to implement the method of the present invention, in any of the described embodiments.

A particular embodiment of the method of the present invention is subsequently described.

Where the determined concentration of polar compounds is below 18.5 %, it is considered that the frying liquid, namely frying oil, is new / has been changed, the information / feedback provided by the method / fryer being that the oil is in such good condition, whereby the information / feedback may be provided by means of a light flashing a green color and/or a wireless message containing such information.

Where the determined concentration of polar compounds is in within a warning range between 18.5 % and 24 %, it is considered that the frying liquid, namely frying oil, is within the warning range, the information / feedback provided by the method / fryer being that the oil is in such range and therefore exchange or partial improvement (for instance, by performing automatic filtering) should be performed soon, whereby the information / feedback may be provided by means of a light flashing a yellow color and/or a wireless message containing such information. A message is also to be sent to a monitor with a remote device, and/or automatic filtering starts, and the heating element is maintained on.

Where the determined concentration of polar compounds is above a predefined maximum value of 24 %, it is considered that the frying liquid, namely frying oil, is not suitable for frying, the information / feedback provided by the method / fryer being that the oil is above such limit and therefore exchange or partial improvement (for instance, by performing automatic filtering) should be immediately performed, whereby the information / feedback may be provided by means of a light flashing a red color and/or a wireless message containing such information. A message is also to be sent to a monitor with a remote device, and/or automatic filtering or automatic exchange start, and the heating element is turned off. Manual exchange of frying liquid may also be performed.

As will be clear to one skilled in the art, the present invention should not be limited to the embodiments described herein, and a number of changes are possible which remain within the scope of the present invention. - IB -

Of course, the preferred embodiments shown above are combinable, in the different possible forms, being herein avoided the repetition all such combinations.