JP4262653B2 - Flyer - Google Patents

Description

  The present invention relates to a fryer that is a dedicated cooking machine for frying various food ingredients for fried foods with cooking oil, and in particular, an electric heater that heats cooking oil, and an oil temperature sensor that detects the temperature of cooking oil, It is related with the flyer provided with.

  As a fryer that fries various food ingredients for fried foods with cooking oil, it has an electric heater that heats cooking oil and an oil temperature sensor that detects the temperature of cooking oil, and an electric heater according to the temperature detected by the oil temperature sensor Conventionally known is one in which the temperature of cooking oil is controlled to a desired set temperature by turning on / off the oil (see, for example, Patent Documents 1 and 2).

Here, as a technique for preventing empty heating of the electric heater and abnormal overheating of cooking oil, Patent Document 1 discloses that when the detected temperature of the oil temperature sensor is lower than a predetermined lower limit temperature or higher than a predetermined upper limit temperature, the electric heater is A flyer control technique that turns off and issues an alarm is disclosed. Further, Patent Document 2 calculates the rate of increase of the temperature detected by the oil temperature sensor, and if the rate of increase is below a predetermined value or above a predetermined value, the electric heater is turned off and an alarm is issued. A control technique is disclosed.
Japanese Patent Laid-Open No. 10-23975 JP 2003-153812 A

  By the way, in this type of fryer, if a disconnection failure occurs in the oil temperature sensor, the temperature of the cooking oil cannot be detected. As a result, the electric heater is turned on and off appropriately to set the cooking oil temperature to a desired setting. It becomes impossible to control the temperature. In addition, the electric heater cannot be turned off properly, and cooking oil may be abnormally overheated.

  However, in the flyer control technique described in Patent Document 1, when a disconnection failure occurs in the oil temperature sensor, the temperature detected by the oil temperature sensor becomes equal to or lower than a predetermined lower limit temperature, so the electric heater is turned off. Abnormal overheating of the cooking oil is prevented and an alarm is issued. However, such processing is executed in response to the disconnection failure of the oil temperature sensor only during the operation of the fryer after the oil temperature sensor detects a predetermined set temperature. Is disconnected, the oil temperature sensor cannot detect the predetermined set temperature at any time, so the process of generating an alarm by turning off the electric heater is not executed.

  On the other hand, in the flyer control technique described in Patent Document 2, when a disconnection failure occurs in the oil temperature sensor, the rate of increase in the temperature detected by the oil temperature sensor becomes a predetermined value or less, so the electric heater is turned off. This prevents abnormal overheating of the cooking oil and gives an alarm. However, calculating the rate of increase in the temperature detected by the oil temperature sensor requires a complicated control process and takes a certain amount of time. Therefore, it is possible to immediately execute the process of turning off the electric heater and generating an alarm. Can not.

  Then, this invention makes it a subject to provide the highly safe fryer which can determine the disconnection failure of an oil temperature sensor from the initial stage after power-on.

  A fryer according to the present invention includes an electric heater that heats cooking oil stored in an oil tank, an oil temperature sensor that detects the temperature of the cooking oil, and the electric heater that is turned on according to the detected temperature of the oil temperature sensor. -A fryer equipped with an oil temperature control means for controlling the temperature of cooking oil to a desired set temperature by turning it off, comprising a failure judgment means for judging a disconnection fault of the oil temperature sensor, A first determination means for comparing the detected temperature of the temperature sensor with a first determined temperature set below the set temperature; and a second determined by setting the detected temperature of the oil temperature sensor lower than the first determined temperature with a predetermined temperature difference. A second determination means for comparing with the temperature, and a timer means capable of continuing the process of the first determination means from the start of energization of the electric heater when the power is turned on until a predetermined time elapses. 1 size If the detected temperature is lower than the second determination temperature, then the disconnection failure of the oil temperature sensor is determined, and if the detected temperature of the oil temperature sensor is lower than the first determination temperature, the timer is After a predetermined time by the means, when the detected temperature is lower than the second determination temperature, the disconnection failure of the oil temperature sensor is determined.

  In the flyer according to the present invention, the detected temperature of the oil temperature sensor is compared with the first determination temperature by the first determination unit of the failure determination unit from the initial stage after the power is turned on, and if the detected temperature is higher than the first determination temperature, It is determined that the oil temperature sensor is normal when the power is turned on. During the subsequent operation of the flyer, the detected temperature of the oil temperature sensor is continuously compared with the second determined temperature by the second determining means, and if the detected temperature becomes lower than the second determined temperature, the oil temperature sensor is broken. It is determined that

  On the other hand, if the detected temperature of the oil temperature sensor is lower than the first determination temperature in the initial stage after the power is turned on, taking into account the decrease in the initial temperature of the cooking oil in a cold region, Until the predetermined time elapses, the temperature detected by the oil temperature sensor is continuously compared with the first determination temperature by the timer means of the failure determination means. If the detected temperature of the oil temperature sensor becomes higher than the first determination temperature as the electric heater is energized, it is determined that the oil temperature sensor is normal when the power is turned on. During the subsequent operation of the flyer, the detected temperature of the oil temperature sensor is continuously compared with the second determined temperature by the second determining means, and if the detected temperature becomes lower than the second determined temperature, the oil temperature sensor is broken. It is determined that

  Here, if the detection temperature of the oil temperature sensor does not become higher than the first determination temperature in spite of energization of the electric heater for a predetermined time, the detection temperature is subsequently compared with the second determination temperature by the second determination means, If the detected temperature is lower than the second determination temperature, it is determined that the oil temperature sensor has failed. On the other hand, if the detected temperature of the oil temperature sensor is higher than the second determination temperature, the detected temperature of the oil temperature sensor is continuously compared with the second determination temperature by the second determination means during the subsequent operation of the fryer. When the temperature becomes lower than the second determination temperature, it is determined that the oil temperature sensor has failed.

  In the fryer according to the present invention, in order to prevent abnormal overheating of the cooking oil, when the disconnection failure of the oil temperature sensor is determined by the failure determination means, the electric heater is turned off and a failure alarm is issued. It is preferable.

  In the flyer according to the present invention, the detected temperature of the oil temperature sensor is compared with the first determination temperature from the initial stage after the power is turned on. In the initial stage after the power is turned on, when the temperature detected by the oil temperature sensor is lower than the first determination temperature, the electric heater is energized for a predetermined time in consideration of a decrease in the initial temperature of the cooking oil in a cold region. The detected temperature of the oil temperature sensor is compared with the first judgment temperature, and when this detected temperature does not become higher than the first judgment temperature, the oil temperature sensor is broken when the detected temperature is lower than the second judgment temperature. It is determined. Further, during operation of the flyer after the power is turned on, it is determined that the oil temperature sensor has failed due to disconnection when the temperature detected by the oil temperature sensor becomes lower than the second determination temperature.

  Therefore, according to the present invention, the disconnection failure of the oil temperature sensor can be determined from the initial state after the power is turned on, and the oil temperature can be determined even when the initial temperature of the cooking oil is lower than the first determination temperature in a cold region. A disconnection failure of the sensor can be determined without error, and high safety can be obtained.

  Embodiments of a fryer according to the present invention will be described below with reference to the drawings. In the drawings to be referred to, FIG. 1 is a perspective view showing the overall structure of a fryer according to an embodiment, and FIG. 2 is a graph showing the relationship between the temperature and resistance value of the oil temperature sensor shown in FIG.

  As shown in FIG. 1, a flyer according to one embodiment includes a box-shaped cabinet 1 having a door-like operation panel 1 </ b> A that can be opened and closed, an oil tank 2 housed in the cabinet 1, and an oil tank 2. The heater unit 3 for heating the cooking oil (frying oil) stored in the inside to predetermined temperature (150-180 degreeC) is provided.

  On the operation panel 1A of the cabinet 1, for example, a 7-segment display 1B is arranged for displaying cooking oil temperature, error messages, and the like. In addition, the operation panel 1A is provided with a power switch SW4 in addition to a temperature raising switch SW1, a temperature lowering switch SW2, and a setting switch SW3 for arbitrarily raising and lowering the temperature of the cooking oil. The temperature raising switch SW1, the temperature lowering switch SW2, and the setting switch SW3 are arranged side by side below the display 1B.

  The heater unit 3 includes an electrical box 3A having both ends rotatably supported at the rear part of the oil tank 2, and the cooking oil in the oil tank 2 is extended from the electrical box 3A into the oil tank 2. The electric heater 3B to be heated and the electric heater 3B is extended substantially horizontally from one end of the electric box 3A to the operation panel 1A side so that the electric heater 3B swings up from the oil tank 2 when the oil tank 2 is cleaned. A swing handle 3C capable of rotating the box 3A is provided.

  The electric heaters 3 </ b> B of the heater unit 3 are arranged in three rows near the bottom of the oil tank 2 while being wound in a loop extending along the longitudinal direction of the oil tank 2. An oil temperature sensor 4 including a thermistor for detecting the temperature of cooking oil is disposed in the vicinity of the base end of the row of electric heaters 3B arranged in the center.

  Here, the oil temperature sensor 4 has a relationship between temperature and resistance as shown in FIG. That is, the resistance value of the oil temperature sensor 4 increases in a hyperbola as the temperature is lower, and decreases in a hyperbola as the temperature is higher. For example, between 0 ° C. and −20 ° C., the resistance value increases dramatically from a value of 300 kΩ or more to about 1000 kΩ, and between 100 ° C. and 250 ° C., the resistance value decreases dramatically from about 10 kΩ toward 0.

  In order to feedback control the temperature of the cooking oil in the oil tank 2 to a desired temperature set by the setting switch SW3 using such temperature characteristics of the oil temperature sensor 4, the oil temperature sensor 4 is input as shown in FIG. It is connected to the Vin terminal of the control device 5 through a circuit. That is, the oil temperature sensor 4 indicated by the resistor Rt is configured with a circuit between the resistor Rt of the oil temperature sensor 4 and the voltage dividing resistor R1, for example, with the DC power source 6 of 5V via the voltage dividing resistor R1. Is connected to the Vin terminal of the control device 5 through the protective resistor R2.

Here, the divided voltage Vin input to the Vin terminal of the control device 5 approaches 5 V as much as the value of the resistance Rt of the oil temperature sensor 4 increases, as shown by the following equation. Therefore, when a disconnection failure occurs in the oil temperature sensor 4, the value of the resistance Rt becomes extremely large and Vin approaches 5V as much as possible. Even when the oil temperature sensor 4 is normal, even if the detected temperature is negative, the value of the resistance Rt of the oil temperature sensor 4 increases from the relationship between the temperature and resistance shown in FIG. Approaches 5V.
Vin = [Rt / (Rt + R1)] × 5 = [1 / (1+ (R1 / Rt))] × 5

  The control device 5 receives switch signals from a temperature rise switch SW1, a temperature fall switch SW2 and a setting switch SW3 on the operation panel 1A. The control device 5 displays a predetermined signal necessary for displaying a temperature designated by the temperature raising switch SW1 or the temperature lowering switch SW2, a temperature set by the setting switch SW3, or an error message as a failure alarm. It is configured to output to 1B.

  Such a control device 5 cooks the oil tank 2 by turning on / off the electric heater 3B according to the detected temperature (resistance value) of the oil temperature sensor 4, that is, according to Vin input to the Vin terminal. In order to feedback control the oil temperature to a desired temperature set by the setting switch SW3, a predetermined drive signal is output to the heater relay 7 that opens and closes the energization circuit of the electric heater 3B.

  Here, the control device 5 is configured by utilizing the hardware and software of a microcomputer, and in addition to the input / output interface I / O and the A / D converter, a ROM (Read Only Memory) storing programs and data. A RAM (Random Access Memory) that temporarily stores input data and the like, a CPU (Central Processing Unit) that executes a program, and the like are provided as hardware. The control device 5 includes, as software, oil temperature control means for turning on / off the electric heater 3B according to the temperature detected by the oil temperature sensor 4 and failure determination means for determining disconnection failure of the oil temperature sensor 4. It is configured.

  In the flyer of the embodiment configured as described above, when the power switch SW4 shown in FIG. 1 is turned on, the oil temperature control means of the control device 5 controls the oil temperature according to the processing procedure of the flowchart of FIG. The process is started, and independently of this, the failure determination means of the control device 5 starts the failure determination process according to the processing procedure of the flowchart of FIG.

  As shown in FIG. 4, in the oil temperature control process by the oil temperature control means, when the power switch SW4 is turned on (SA1), a heater OFF signal is first output to the heater relay 7 (SA2). As a result, the heater relay 7 is turned off and the electric heater 3B is turned off in a non-energized state, and the cooking oil in the oil tank 2 is maintained in a state where heating is stopped.

  In the subsequent step SA3, it is determined whether or not an alarm for disconnection failure of the oil temperature sensor 4 is being output depending on whether or not an alarm signal A is input from a failure determination means described later. If this determination result is YES, it is estimated that a disconnection failure has occurred in the oil temperature sensor 4, and the process returns to step SA2 to output a heater OFF signal.

  On the other hand, if the determination result in step SA3 is NO, it is estimated that the oil temperature sensor 4 is normal. In the next step SA4, a signal of the set oil temperature T corresponding to the switch signal of the setting switch SW3 is input. The Subsequently, a signal of the detected oil temperature t corresponding to the input voltage of Vin based on the resistance value of the oil temperature sensor 4 is input (SA5). In step SA6, it is determined whether or not the detected oil temperature t is lower than the set oil temperature T.

  If the determination result in step SA6 is NO, the process returns to step SA3 to wait for the oil temperature to decrease, and it is determined whether an alarm is being output. If YES, the heater is determined in the next step SA7. An ON signal is output to the heater relay 7. As a result, the heater relay 7 is turned on, the electric heater 3B is turned on, and heating of the cooking oil in the oil tank 2 is started.

  Thereafter, in order to continue the oil temperature control, the processes of steps SA8 to SA10 similar to steps SA3 to SA5 described above are repeated. In step SA11 following step SA10, it is determined whether or not the detected oil temperature t has become equal to or higher than the set oil temperature T. When this determination result is NO, in order to wait for the oil temperature to rise, the process returns to step SA8 to determine whether an alarm is being output.

  On the other hand, if the decision result in the step SA11 is YES, the process returns to the step SA2 to output a heater OFF signal to the heater relay 7. As a result, the heater relay 7 is turned off, the electric heater 3B is turned off in a non-energized state, and heating of the cooking oil in the oil tank 2 is stopped.

  Thereafter, feedback control is performed so that the temperature of the cooking oil in the oil tank 2 becomes the set oil temperature T by repeating the processes of steps SA3 to SA11. Note that such an oil temperature control process ends when the power switch SW4 is turned off.

  On the other hand, as shown in FIG. 5, in the failure determination process by the failure determination means, when the power switch SW4 is turned on (SB1), a timer is first started (SB2). Thereafter, a signal of the detected oil temperature t corresponding to the input voltage of Vin based on the resistance value of the oil temperature sensor 4 is input to the first determination means, whereby the detected oil temperature t is the first determination temperature, for example, 10 ° C. It is determined whether it is less than (SB3).

  Here, the first determination temperature is set to 10 ° C. The oil temperature of the cooking oil in the oil tank 2 is normally 15 to 30 ° C. If the oil temperature sensor 4 is normal, the detected oil temperature t is It is because it becomes 10 degreeC or more.

  If the decision result in the step SB3 is YES and the detected oil temperature t is less than 10 ° C., it is judged by the timer means whether or not a predetermined time has elapsed from the timer start in the step SB2 and the timer is up. (SB4). If this determination result is NO, the process returns to step SB3 in order to wait for the oil temperature to rise due to energization of the electric heater 3B. This process is for a case where the initial temperature of the cooking oil is less than 10 ° C. in a cold district or the like even though the oil temperature sensor 4 is normal.

  If the determination result in step SB3 is NO and the detected oil temperature t is 10 ° C. or higher, it is estimated that the oil temperature sensor 4 is normal when the power is turned on, and the process proceeds to step SB5. If the determination result in step SB4 is YES and the timer is up, the process proceeds to step SB5 in order to confirm the disconnection failure of the oil temperature sensor 4 when the power is turned on.

  In step SB5, whether or not the detected oil temperature t is lower than the second determination temperature, for example, 0 ° C., is determined by the second determination unit to which the signal of the detected oil temperature t is input. If the determination result is NO and the detected oil temperature t is 0 ° C. or higher, the process of step SB5 is repeated to continuously monitor the disconnection failure of the oil temperature sensor 4 during the operation of the fryer.

  On the other hand, if the determination result in step SB5 is YES and the detected oil temperature t is less than 0 ° C., it is estimated that a disconnection failure has occurred in the oil temperature sensor 4, and the process proceeds to the subsequent step SB6. In step SB6, an alarm signal A as a failure alarm is output to the display 1B disposed on the operation panel 1A, and an error message indicating that a disconnection failure has occurred in the oil temperature sensor 4 is displayed on the display 1B. The

  In subsequent step SB7, in order to reconfirm the disconnection failure of the oil temperature sensor 4, the detected oil temperature t becomes equal to or higher than 0 ° C., which is the second determination temperature, by the second determining means to which the signal of the detected oil temperature t is input. It is determined whether or not. And if this determination result is NO, the disconnection failure of the oil temperature sensor 4 will be confirmed, and it will return to step SB6.

  On the other hand, if the decision result in the step SB7 is YES, it is estimated that the disconnection failure has not occurred in the oil temperature sensor 4, and the output of the alarm signal A is canceled in the subsequent step SB8, and then the process returns to the step SB5. .

  Thus, in the flyer according to the embodiment, the detected temperature t of the oil temperature sensor 4 is compared with the first determination temperature (for example, 10 ° C.) from the initial stage after the power is turned on, and the initial stage after the power is turned on. In the case where the temperature t detected by the oil temperature sensor 4 is lower than the first determination temperature (for example, 10 ° C.), the electric heater 3B is energized for a predetermined time in consideration of a decrease in the initial temperature of cooking oil in a cold region. The detected temperature t of the oil temperature sensor 4 is compared with a first determination temperature (for example, 10 ° C.).

  In the initial stage after the power is turned on, if the detected temperature t of the oil temperature sensor 4 does not become higher than the first determination temperature (for example, 10 ° C.) even though the electric heater 3B is energized for a predetermined time, the detected temperature When t is lower than the second determination temperature (for example, 0 ° C.), it is determined that the oil temperature sensor 4 is broken. Further, during operation of the flyer after the power is turned on, when the detected temperature of the oil temperature sensor 4 becomes lower than the second determination temperature (for example, 0 ° C.), it is immediately determined that the oil temperature sensor 4 is broken. The

  When the disconnection failure of the oil temperature sensor 4 is determined, the electric heater 3B is turned off and an error message is displayed on the display 1B. Therefore, overheating of the electric heater 3B and abnormal overheating of the cooking oil are prevented. Is done.

  Thus, according to the flyer of one embodiment, the disconnection failure of the oil temperature sensor 4 can be determined from the initial state after the power is turned on. Further, since the initial temperature of the cooking oil is lower than the first determination temperature (for example, 10 ° C.) and lower than the second determination temperature (for example, 0 ° C.) in the cold region, the value of the resistance Rt of the oil temperature sensor 4 is broken. Even in the case of approximating the value at this time, the disconnection failure of the oil temperature sensor 4 is determined by the detected temperature t of the oil temperature sensor 4 after the electric heater 3B is energized for a predetermined time. 4 disconnection faults can be determined without error, and high safety can be obtained.

It is a perspective view showing the whole fryer structure concerning one embodiment of the present invention. It is a graph which shows the relationship characteristic of the temperature and resistance value of the oil temperature sensor shown in FIG. It is a circuit diagram which shows the input / output of the microcomputer into which the detection signal of the oil temperature sensor shown in FIG. 1 is input. It is a flowchart which shows the procedure of the oil temperature control process by the microcomputer shown in FIG. It is a flowchart which shows the procedure of the failure determination process by the microcomputer shown in FIG.

Explanation of symbols

1 cabinet 1A operation panel 1B display 2 oil tank 3 heater unit 3A electrical box 3B electric heater 3C swing handle 4 oil temperature sensor 5 controller 6 DC power supply 7 heater relay SW1 temperature rise switch SW2 temperature drop switch SW3 setting switch SW4 power switch

Claims (1)

An electric heater for heating cooking oil stored in the oil tank, an oil temperature sensor for detecting the temperature of the cooking oil, and cooking oil by turning on and off the electric heater according to the detected temperature of the oil temperature sensor In a fryer equipped with an oil temperature control means for controlling the temperature of the oil to a desired set temperature,
A failure determination means for determining a disconnection failure of the oil temperature sensor; the failure determination means; a first determination means for comparing the detected temperature of the oil temperature sensor with a first determination temperature set below the set temperature; A second determination means for comparing the detected temperature of the oil temperature sensor with a second determination temperature set lower than the first determination temperature with a predetermined temperature difference; and a predetermined time from the start of energization of the electric heater when the power is turned on Timer means capable of continuing the processing of the first determination means until after elapse,
If the detected temperature of the oil temperature sensor is higher than the first determination temperature, then a disconnection failure of the oil temperature sensor is determined when the detected temperature becomes lower than the second determination temperature, and the oil temperature When the detected temperature of the sensor is lower than the first determination temperature, the disconnection failure of the oil temperature sensor is determined when the detected temperature is lower than the second determination temperature after a lapse of a predetermined time by the timer means. Characteristic flyer.

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