KR0155465B1 - Display device - Google Patents

Abstract

(Objective) A display device for displaying the number of combustions and the duration of combustion of a combustor on a display that normally displays the current time and temperature at the time of inspection, etc., wherein a predetermined range of digits of the integrated value read out from the storage means can be displayed. Even if the number of digits is exceeded, the approximate number of combustions or the combustion time can be determined.

(Configuration) In the display 4 on which the current time is normally displayed, a number relating to the number of times of combustion or the time of combustion of the gas burner 2 is displayed at the time of the inspection operation, and the number of scheduled display is possible. When the number of digits is exceeded, H is displayed on the display portion 41 of the indicator 4, and the upper three digits of the number are displayed on the display portions 42, 43, and 44. FIG.

Description

Display

1 is a block diagram of an FF gas heater according to an embodiment of the present invention.

2 is a block diagram of the FF gas hot air heater.

3 is an explanatory diagram of a panel surface of the FF gas heater.

4 is an explanatory diagram showing a display state of an indicator assembled to the panel surface;

5 is a flow chart showing the state of measurement and storage of combustion time and number of combustions in the FF gas-heated air heater.

FIG. 6 is a flowchart showing a state in which the integrated value of the combustion time and the number of combustions is displayed on the display in the FF gas-heated air heater.

* Explanation of symbols for main parts of the drawings

A: FF gas-heated air heater (display device) 2: gas burner (combustor)

4 indicator 41, 44 indicator (segment)

381: measuring means 382: integration means

383: indicator control means 384: display change means

391 RAM (memory means) 392 E ² PROM (memory means)

401 to 406: light emitting portion (predetermined portion)

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device for displaying the number of times of operation of a device or the time of operation of a device at a time of inspection work on an indicator on which a current time is displayed.

For example, in a combustion apparatus for sending warm air generated by burning fuel to a heating target, the combustion device for heating the target is stored in a built-in microcomputer to store the sum of the combustion time or the operating time, and the stored combustion time or operation. BACKGROUND ART A combustion apparatus which displays the time on a display has been known in the past (Japanese Patent Laid-Open No. 3-95307).

By confirming the cumulative combustion time and the running time, the use status of the device can be known and the degree of deterioration of the device can be estimated.

By the way, the said conventional combustion apparatus has the inconvenience as shown below.

If the sum of the combustion time or the operation time exceeds the display digits of the indicator, the sum of the combustion time or the operation time will not be displayed normally on the indicator, which will interfere with the inspection work.

A first object of the present invention is a display device for displaying the number of times of operation and the time of operation of a device at a time of inspection work on a display on which a current time or temperature is normally displayed, wherein a predetermined digit range of the integrated value read out from the storage means is shown. Even if the display exceeds the displayable digit of the indicator, it is possible to grasp the approximate number of operations or the operation time.

A second object of the present invention is a display device for displaying the number of combustions and the combustion time of a combustor on a display in which a current time or a temperature is normally displayed at the time of inspection work, wherein a predetermined digit range of the integrated value read out from the storage means is Even when the displayable digits of the indicator are exceeded, the approximate number of combustions and the combustion time can be grasped.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, this invention employ | adopted the following structures.

(1) A display capable of displaying a number, measuring means for measuring the number of times of operation or operating time of a device, storage means for storing an integrated value relating to the number of times of operation of a device or operating time, and an integrated value stored in the storage means. At the same time, the integration means for updating the accumulated integrated value and rewriting the integrated value of the storage means, and the integrated value stored in the storage means is read out and the accumulated operation time and the accumulated operation number of the device are left as they are (1 / A display device of a device comprising display control means for performing decimal display on said display, wherein when the number to be displayed exceeds the displayable number of digits of the display, the display device has a predetermined form at the beginning or the end of the display. Display changing means was provided to display the upper digit of the number and display only the (displayable digit-1) digit.

(2) A display capable of displaying a number, measuring means for measuring the number of combustions or the combustion time of the combustor, storage means for storing the number of combustions or the combustion time of the combustor, and an integrated value stored in the storage means. At the same time as reading, the integration means for updating the integrated value read out and rewriting the integrated value of the storage means and the integrated value stored in the storage means are read out, and the combustion time and the number of times of combustion of the combustor are unchanged or (1/10). In the display apparatus of the combustion apparatus provided with the indicator control means which performs decimal display on the said display, WHEREIN: When the number to be displayed exceeds the displayable number of digits of the said display, the display of a predetermined | prescribed form is shown in the head or tail of the said display. And display change means for displaying only the upper digit of the number (the number of digits that can be displayed).

(3) With the configuration of (1) or (2) above, the indicator is a light emitting diode display or liquid crystal display in which a predetermined portion of the segment emits light or the light transmittance is reduced to perform the display of numbers or the specific style.

4 has a configuration of (1), (2) or (3), the storage means is a E ² PROM.

The method of claim 1, wherein the measuring means measures the number of times of operation or the time of operation of the device.

The computing means reads out the integrated value stored in the storage means, updates the accumulated integrated value, and rewrites the integrated value of the storage means.

The indicator control means reads out the accumulated value stored in the memory means at the time of checking, etc. and multiplies the accumulated operation time or the accumulated operation number of the device as it is or (1/10 ms) (where n is an integer of 1, 2, 3,…). Decimal display is performed on the display.

When the number to be displayed exceeds the displayable digit of the display, the display change means displays a predetermined form at the front or the rear of the display to display only the upper digit of the number (displayable digit-1).

At the time of inspection, the number displayed on the display unit is as it is or 10ⁿ times (where n is an integer of 1, 2, 3, ...) to be the integrated operation time or the accumulated operation number of the self. In addition, when a display of a predetermined form is displayed at the beginning or the end of the display, the number displayed on the display is multiplied by a predetermined magnification, and the value is left or 10 times multiple (where n is an integer of 1, 2, 3), and the approximate integration operation time. Or accumulated operation count. The service man performs the service work based on the accumulated operation time or the accumulated operation frequency.

The method of claim 2, wherein the measuring means measures the number of combustions or the combustion time of the combustor.

The integration means reads out the integrated value stored in the storage means, updates the accumulated integrated value, and writes the integrated value into the storage means.

The indicator control means reads out the integrated value stored in the memory means at the time of checking, etc. and multiplies the combustion time or the number of times of combustion of the combustor as it is (where n is an integer of 1, 2, 3). Do it.

If the number to be displayed exceeds the number of displayable digits of the display, the display changing means displays a predetermined form at the beginning or the end of the display to display only the upper digit of the number (displayable digit-1).

At the time of inspection, the number displayed on the display unit is either 10 times or 10 times (where n is an integer of 1, 2, 3, ...) to determine the integrated combustion time and the number of times of integrated combustion. When a display of a predetermined form is displayed at the beginning or the end of the display, the number displayed on the display is multiplied by a predetermined magnification, and as it is or 10 times multiple (where n is an integer of 1, 2, 3, ...), the approximate integrated combustion is performed. The number of hours or cumulative combustion is obtained. The service man performs the service work based on the accumulated burn time or accumulated burn count.

The display device according to claim 3, wherein the indicator is a light emitting diode display or a liquid crystal display in which a predetermined portion of a segment emits light or decreases light transmittance, and displays a number or a specific form, and the number of operation of the presently-timed device (the number of combustion of the burner). Or display of a number indicating the operating time of the appliance (burning time of the combustor) or in a particular form (when the number to be displayed exceeds the displayable number of digits of the indicator).

The E ² PROM stores an integrated value relating to the number of times of operation and an operating time of the device, or an integrated value relating to the number of times of combustion or the time of combustion of the combustor.

In the case of claim 1, when the number to be displayed exceeds the displayable digit of the display, a predetermined form is displayed at the front or the rear of the display to display only the upper digit of the number (displayable digit-1). The number displayed on the display is multiplied by a predetermined magnification, and it is as it is or 10 times (where n is 1, 2, 3, ... is an integer), so that the approximate integration operation time and the integration operation number of the device can be known. The serviceman can perform the service work correctly based on this information.

3. The display change means according to claim 2, wherein when the number to be displayed exceeds the number of displayable digits of the display, the display changing means displays a predetermined form at the beginning or the end of the display device to display the upper digit of the number (displayable digit-1). Only moisture is displayed.

The number displayed on the display is multiplied by a predetermined magnification, or 10 times (where n is an integer of 1, 2, 3, ...) to know the approximate integrated combustion time and the number of operations of the combustor. The service work can be performed correctly based on the information.

4. The display according to claim 3, wherein the indicator performs numeral or specific style display by emitting a predetermined portion of the segment or decreasing light transmittance. As it is a light emitting diode display or liquid crystal display, in addition to the display of the number indicating the current time, the number of operation of the device (burning time of the combustor), or the operating time of the device (burning time of the combustion device), the number of the display is indicated by the displayable number of digits. It is possible to display a particular form indicating that it is exceeding.

The integrated value according to the number of times of operation and the time of operation of the device or the total number of times of combustion or the time of combustion of the combustor is stored in the E ² PROM. .

An embodiment of the present invention will be described based on FIGS. 1 to 6 (corresponding to claims 1 to 4).

As shown in FIG. 1 and FIG. 2, the FF type gas warm air heater A includes a gas burner 2 to which gas is supplied via the solenoid valves 11 and 12 and the gas proportional valve 13, and a sparker. And a combustion controller 3 for controlling the combustion fan 32, the solenoid valves 11 and 12, and the gas proportional valve 13, and an indicator 4. Further, 51 is a frame rod, 52 is a hot air passage, 53 is a convection fan disposed in the hot air passage 52, 54 is a combustion air passage, and 55 is a high limit dummyster for detecting abnormal temperature rise.

The gas burner 2 has a flame port 211 for discharging the mixer at the front end, and passages 21, 21,... Where the mixer inlet 212 for suctioning primary air and gas is formed at the base end. ) And a gas pipe 22 having nozzles 221, 221,... Positioned at the mixer inlet 212 of the passage 21. The gas pipe 22 has solenoid valves 11, 12 and a gas proportional valve ( Gas is supplied by the gas pipeline (g), which is given in step 13), forcibly combusted.

The sparker 31 is disposed in response to the flame port 211, and when the high voltage is applied by the sparker drive circuit 36 during the ignition operation, the gas burner 2 is ignited.

The combustion fan 32 is composed of an impeller 321 pivoted in the combustion air passage 54 upstream of the gas burner 2, and a combustion fan motor 322 (direct current motor) for driving the impeller 321. Then, the indoor air 320 is supplied to the gas burner (2). The combustion fan 32 rotates at an ignition speed during ignition, and at a temperature of rotation temperature (1300 rpm to 3600 rpm) at which combustion air suitable for the required combustion amount is obtained during temperature control.

The gas proportionality valve 13 is a valve whose opening degree increases with the amount of energization, and increasing the amount of energization increases the amount of gas supplied to the gas burner 2. The solenoid valves 11 and 12 become open when energized, and supply gas to the gas burner 2. In the gas proportional valve 13, a proportional valve current of the ignition level flows during ignition, and a proportional valve current of an on-level level corresponding to the temperature of rotation of the combustion fan 32 flows during the warming.

The frame rod 51 faces a combustion flame and detects a flame current.

The hot air passage 52 is provided with an air inlet 521 for opening the upper portion of the heater housing to suck the indoor air 520 and an air outlet 523 for opening the hot air 522 to the interior of the heater housing. It is a communication path. In addition, a filter f for removing dust in the room is detachably disposed at the suction port 521, and a guide plate 524 for changing the blowing direction of the warm air 522 is assembled at the blowing port 523. .

The convection fan 53 is composed of an impeller 531 pivoted in the hot air passage 52 in the vicinity of the inlet 521 and a convection fan motor 532 (alternating motor) for driving the impeller 531. Air flow 533 toward the jet port 523 is generated. At the time of warming, the convection fan 53 flows a current having a level in which an air volume proportional to the required combustion amount is obtained.

The combustion air passage 54 is a passage connected to the inlet / exhaust port of the double intake / exhaust duct in which the upstream end side and the downstream end side are addressed to the outside, and a blowing unit 543 which sends combustion air to the gas burner 2. And a heat exchanger 541 for discharging the heat of the combustion exhaust gas 540 generated by the combustion into the air flow 533 in the passage. In addition, the combustion chamber 541 and the heat exchanger 542 are located in the warm air passage 52.

The combustion controller 3 includes a proportional valve driving circuit 33 for driving the gas proportional valve 13, a solenoid valve driving circuit 14 for opening and closing the solenoid valves 11 and 12, and a convection fan motor 532. A convection fan motor drive circuit 34 for driving, a combustion fan motor drive circuit 35 for feedback control of the combustion fan motor 322, a sparker drive circuit 36 for driving the sparker 31, A display circuit 37 for driving the display device 4 or a lamp, and a microcomputer 38 for controlling the respective drive circuits.

The microcomputer 38 has a measurement means 381, an integration means 382, a display control means 383, and a display change means 384. 391 and 392 are RAMs and E ² PROMs in which an integrated value of rotation speed and combustion time of the gas burner 2 is stored.

The measuring means 381 measures the number of combustions and the combustion time of the gas burner 2, respectively, based on the number of times of ignition detection by the frame rod 51 and the time from ignition detection to fire detection (flow chart of FIG. 5). Reference). The integration means 382 updates the integrated value of the combustion time and the number of combustion times of the gas burner 2 in the RAM 391 based on the measurement result of the measurement means 381, and each time a combustion time of 60 minutes is measured. The integrated value of the combustion time and the number of combustions in the RMA 391 is written into the E ² PROM 392 (see the flowchart of FIG. 5).

In addition, although the limit of the normal number of times of writing the E ² PROM is about 100,000, in this embodiment, since the writing is performed in the E ² PROM 392 only when the combustion time of 60 minutes is measured, the number of writing is No more than 100,000 times.

When the indicator control means 383 enters the maintenance mode (operation of the maintenance switch M), the accumulated combustion time (1 hour unit; Tf) stored in the E ² PROM 392 or the accumulated combustion count (10 times unit). Tm) is read out (refer to the flowchart of FIG. 6).

While the accumulated integration burn time is 10,000 hours and the actual accumulated burn time does not reach 100000 times, the accumulated burn time and accumulated burn times read out from the E ² PROM 392 are accumulated in the display 4, for example. The display circuit 37 is instructed to display a decimal time such as 9999 for burning time or 9999 on a scale of 1/10 < 1 > times (see Fig. 4A).

As shown in the flowchart of FIG. 6, the display change means 384 displays H, meaning 100 times, on the display portion 41 at the left end of the indicator 4 when the accumulated combustion time is 10000 hours or more. The display circuit 37 is instructed to display only the upper three digits of the cumulative combustion time on the display sections 42, 43, and 44 (see (b) and (c) in FIG. 4).

In the case where the cumulative combustion number is 100000 times or more, the display portion 41 at the left end of the display unit 4 displays H, which means 100 times, and only the three-digit portion of the integrated combustion number is displayed on the display units 42, 43, 44. The display circuit 37 is instructed to be displayed (see (b) and (c) in FIG. 4).

The RAM 391 is a temporary memory for the combustion time and the number of combustions, and the integrated value is held during energization (while the power cord is inserted into the outlet). The E ² PROM 392 is a nonvolatile memory that semi-permanently stores the integrated value of the combustion time and the number of combustions.

The indicator 4 is a seven-segment light emitting diode display, for example, 8 is displayed by emitting light from the light emitting parts 401 to 407, and H is emitted by emitting the light emitting parts 402, 403, 404, 405, and 406. Is displayed. The indicator 4 displays the current time, operation start time, operation end time, set temperature or room temperature, and the gas burner 2 displays the number of accumulated combustion time and the number of times of accumulated combustion during the inspection work. do.

The time is displayed on the display sections 41, 42, 43, 44, the set temperature is displayed on the display sections 41, 42, and the room temperature is displayed on the display sections 43, 44.

Next, the operation of the FF type gas hot air heater A will be described.

When the target room temperature upswitch 301 and the down switch 302 are set and the operation switch SW is operated on, the combustion controller 3 operates (normal operation) as follows.

The combustion fan motor driving circuit 35 is instructed so that the combustion fan 32 rotates at the ignition speed. The solenoid valve driving circuit 14 is instructed to keep the solenoid valves 11 and 12 open. The proportional valve driving circuit 33 is instructed so that the gas proportional valve current becomes the ignition level. The sparker driving circuit 36 is instructed to operate the sparker 31 for a predetermined time.

When the ignition is detected and a predetermined time has elapsed, the combustion fan motor driving circuit 35 is instructed so that the combustion fan rotates at an on-board rotational speed at which combustion air suitable for the required combustion amount is obtained. In addition, the proportional valve driving circuit 33 is instructed so that the proportional valve current corresponding to the detected rotational speed of the combustion fan 32 flows.

Next, a method of measuring the cumulative combustion frequency and the cumulative combustion time of the gas burner 2 in the FF type gas hot air heater A will be described based on the flowchart shown in FIG.

When the missing power cord is plugged in, start from step S1, and the microcomputer 38 calculates the accumulated burn time T _f (hour) and the accumulated burn count Tm (× 10 times) from the E ² PROM 392. ) Is read into RAM 391 and proceeds to step S2. If the power cord is plugged in, start from step S2.

In step S2, the microcomputer 38 determines whether or not an instruction to start operation has been made, and if so (YES), the process goes to step S3. On the basis of the output transmitted by the frame rod 51 in the step S3, the microcomputer 38 determines the ignition detection, and when the ignition detection is detected (YES), the process proceeds to the step S4.

In step S4, the combustion count S is integrated (burn count S = burn count S + 1), and the process proceeds to step S5. In step 5, the microcomputer 38 starts (or resumes) the 60 minute timer t and proceeds to step 6.

When the digestion is detected by the microcomputer 38 determining the extinguishing detection based on the output transmitted by the frame rod 51 in the step S6 (YES), the process proceeds to the step S7 and when the digestion is not detected (NO) Proceeds to step S8.

In step S7, the microcomputer 38 stops counting the 60 minute timer t, and returns to step S3.

In step S8, it is determined whether or not the number of combustions S has reached 10 times. If S = 10 (YES), the process proceeds to step S9, and in case of S10 (NO), the process proceeds to step S11. In step S9, the number of combustions S is returned to zero (S = 0 is executed), and the process proceeds to step S10.

In step S14, it is determined whether the combustion time Tf (integrated value) is greater than or equal to 65535 (16-bit storage limit value), and in the case of Tf65535 (NO) proceeds to step S15, and in the case of Tf65535 (YES), step S18 Proceed to

In step S15, it is determined whether the combustion number Tm (integrated value) is 65535 or more, and in the case of Tm65535 (YES), the processing proceeds to step S17.

In step S16, the combustion time Tf (integrated value) and the combustion number Tm (integrated value) are stored in the E ² PROM 392, and the processing proceeds to step S21.

In step S17, the combustion time Tf (integrated value is stored in the E ² PROM 392, and the process proceeds to step S21.

In step S18, it is determined whether the combustion number Tm (integrated value) is 65535 or more, and in the case of Tm65535, NO proceeds to step S19, and Tm In the case of 65535 (YES), the processing proceeds to step S20. In step S19, the combustion count Tm (integrated value) is stored in the E ² PROM 392, and the process proceeds to step S21.

Measurement stops with staff S20.

Next, the operation of the maintenance mode in the FF gas-heated air conditioner A will be described based on the flowchart of FIG.

During the operation stop, the microcomputer 38 detects the presence or absence of the operation of the maintenance switch M (exposed on the control board), and when the operation is detected (steps S1 to YES), the microcomputer 38 proceeds to step S2. If the operation is not detected (NO in step S1), step S1 is repeated.

The microcomputer 38 in the S2 staff reads the burning time Tf (integrated value) and the number of combustion Tm (integrated value) from the E ² PROM (392), and goes to the staff S3.

At step S3 the microcomputer 38 burns time Tf. It is determined whether or not 10000 is satisfied, and if it is not satisfied (NO), the process proceeds to the step S4, and when it is satisfied (YES), the process proceeds to the step S5.

In step S4, the microcomputer 38 instructs the display circuit 37 to display the combustion time Tf for one second on the display 4 (see FIG. 4A), and proceeds to stamp S7.

In step S5, the microcomputer 38 divides the combustion time Tf by 100 to obtain a combustion time T _F (about 100 times) which does not drop to a decimal point.

In step S6, H means 100 times is displayed on the display portion 41 at the left end of the display 4 for one second, and the combustion time T _f- is displayed on the display portions 42, 43, and 44 (fourth). (B) and (c)), the microcomputer 38 instructs the display circuit 37. FIG.

In step S7, the microcomputer 38 determines whether the combustion number Tm is 10000 or more, and Tm. In the case of 10000 (YES), the process proceeds to the staff S9, and in the case of Tm10000, the process proceeds to the staff S8. In step S8, the microcomputer 38 instructs the display circuit 37 to display the combustion time Tm for one second on the display 4 (see FIG. 4A), and returns to step S3.

In step S9, the microcomputer 38 divides the number of combustions Tm by 100, cuts off the decimal point, and finds the number of combustions Tm (about 1000 times).

In step S10, H indicating the display unit 41 DP 100 times at the left end of the display unit 4 is displayed for one second, and the number of combustions Tm (about 100 times) is displayed on the display units 42, 43, and 44. (See (b) and (c) of FIG. 4), the microcomputer 38 instructs the display circuit 37 to return to the step S3.

Next, the advantages of the FF type gas warm air heater A of the present embodiment will be described.

A) When the service man operates the maintenance switch M to put the FF gas heater unit in maintenance mode, the integrated value of the combustion time (1 hour unit) is followed by the combustion count (10 times unit). ) Are displayed on the indicator 4 for 1 second each.

At this time, when the integrated values Tf and Tm exceed four digits, H is displayed on the display unit 41 at the left end, and the upper three digits (four or fewer digits) of the integrated values are displayed on the display units 42, 43, and the like. 44) for 1 second.

If the H mark is not displayed, the serviceman can calculate the approximate accumulated burning time or integrated operation by using the number displayed on the indicator 4 (display of accumulated combustion time) or 10 times (displayed the number of accumulated combustion times). The number of times can be known, and service work can be performed accurately and reliably based on these information. In addition, if the cumulative combustion count or the cumulative combustion time is large, knowing the approximate value will not interfere with the maintenance work.

B) On the display 4 of the FF gas heater unit A, the light emitting units 401 to 407 of the display units 41 to 44 emit light to display the current time, room temperature, and set temperature numerically with good visibility. A bladder diode array that can be used is usually used. In the normal use, the display may be four digits, and the display of the four digits is used for the indicator 4 because of the increase in the occupied area in the display panel P and the increase in the number of parts.

In the case of the digit over, the H display is performed so that only the upper digit is displayed so that the occupied area in the display panel P does not increase or the number of parts increases.

C) In the FF type gas warm air heater (A) of this embodiment, the integrated value of the combustion time (Tf) or the number of combustions (Tm) is stored in the E ² PROM 392. Loss of the integrated value does not occur.

D) Numerical value regarding the combustion time Tf or the number of combustions Tm displayed on the indicator 4 in the maintenance mode.

Is a decimal display, so the service man must display 1 times (burn time without H mark), 10 times (burn time without H mark), 100 times (burn time with H mark) The approximate combustion time (Tf) and the combustion number (Tm) can be known only by performing the 1000 times (combustion time at the time of H display) and 1000 times (combustion time at the time of H display).

The present invention includes the following embodiment in addition to the above embodiment.

a. The display device having the configuration of the present invention may be applied to a hot water heater, a gas stove, a clothes dryer, or the like. Moreover, apparatuses other than a combustion apparatus may be sufficient.

b. The display of the predetermined form to be performed when the number to be displayed exceeds the displayable number of digits of the indicator may be the tail of the indicator. If the display is anything other than numbers, it may be a display other than H (e.g., P. S, etc.).

c. In the above embodiment, it was shown that the combustion time and the number of combustion are alternately displayed, but only one of them may be displayed.

d. In the above embodiment, the combustion time and the number of combustions are displayed by operating the maintenance switch M. However, when an abnormality occurs therein, the display may be automatically displayed.

Claims (4)

A display capable of displaying a number, measuring means for measuring the number of times of operation or the time of operation of the device, storage means for storing an integrated value relating to the number of times of operation and the time of operation of the device, reading out the total value stored in the storage means; At the same time, the integrated means for updating the accumulated integrated value and rewriting the integrated value of the storage means and the integrated value stored in the storage means are read out, and the accumulated operation time and the accumulated operation number of the apparatus are multiplied as it is or 1/10 ms. In the display apparatus of the apparatus provided with the display control means which carries out decimal display on the said display, WHEREIN: When the number to be displayed exceeds the displayable number of digits of the said display, a display of a predetermined form is performed by the display at the head or tail of the said display. Display characterized in that the display changing means for displaying only the number of digits (displayable digits -1) digits of the upper digit of the display is provided. Device. A display capable of displaying a number, measuring means for measuring the number of combustions and the combustion time of the combustor, storage means for storing an integrated value relating to the number of combustions and the combustion time of the combustor, reading out the integrated value stored in the storage means; At the same time, the integration means for updating the accumulated integration value and rewriting the integration value of the storage means, and reading out the integrated value stored in the storage means, multiplying the combustion time and the number of combustions of the combustor as it is or by 1/10 times the display. In the combustor of the combustor provided with the indicator control means which carries out decimal display in the case, when the number to be displayed exceeds the displayable number of digits of the said indicator, a predetermined form is displayed on the head or the trailing edge of the indicator, and the upper digit of the number is shown. A display cabinet characterized in that a display changing means is provided for displaying only the number of digits (displayable digits-1). Chi. The display device according to claim 1 or 2, wherein the indicator is a light emitting diode display or a liquid crystal display in which a predetermined portion of the segment emits light or decreases the light transmittance to display a number or the specific form. The display device according to claim 1, wherein the storage means is an E ² PROM.