Electronic apparatus

Abstract

In an electronic apparatus in which plural substrates are arranged in a perpendicular direction between plural cooling fans in a lower part of a case and plural temperature sensors in an upper part of the case, any temperature variation by 2° C. in three seconds detected by any one of the temperature sensors is determined to be abnormal, and thermal energy is caused to be discharged from surfaces of substrates on two sides of a flame by raising air flow rates of fans. Expansion of the flame to other substrates is thereby prevented.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described in conjunction with the accompanying drawings, in which:

FIGS. 1A and 1B show a perspective view of an electronic apparatus;

FIG. 2 shows a perspective profile of the electronic apparatus;

FIG. 3 is a block diagram illustrating fan control;

FIG. 4 is a block diagram illustrating the contents of a memory;

FIG. 5 is a flowchart illustrating control of the frequency of fan revolutions regarding determination of abnormality;

FIG. 6 illustrates air temperature variations in a temperature sensor and a case when abnormality is determined according to the absolute temperature;

FIG. 7 illustrates determination of abnormality according to temperature variations;

FIGS. 8A to 8C illustrate the methane gas flow rate profile, the air flow rate of the fan and the air temperature in the case after ignition;

FIG. 9 illustrates a PCB area; and

FIG. 10 illustrates a temperature sensor area.

Claims

1-10. (canceled)

11. An electronic apparatus comprising a plurality of cooling fans arranged in a lower part of a case, a plurality of temperature sensors arranged in an upper part of said case, and a plurality of electronic substrates so arranged between said cooling fans and said temperature sensors as to secure air flow paths, with an ambience test of inserting an ignition source for a certain length of time into the case imposed, characterized in that: said electronic apparatus having a control unit that measures at predetermined intervals of time the temperature within the case with individual ones of said temperature sensors, compares the temperature measured the latest time with the temperature measured at the preceding time for each of said temperature sensors and, if the temperature measured the latest time is higher by a predetermined value than the temperature measured at the preceding time for one or more of said temperature sensors, increases an air flow rate of said plurality of cooling fans.

12. The electronic apparatus according to claim 1, wherein said control unit further checks each temperature sensor for which the temperature measured the latest time is higher by the predetermined value than the temperature measured at the preceding time by comparing the temperaturc measured at the preceding time with the temperature measured at the time immediately before that preceding time and, if there is at least one of said temperature sensors whose difference is greater than 0° C., increases the air flow rate of said plurality of cooling fans.

13. The electronic apparatus according to claim 1, wherein the air flow rate of said cooling fans is increased from a normal range of 0.5 m/s to 0.8 m/s to a range of 1.2 m/s to 1.7 m/s.

14. The electronic apparatus according to claim 2, wherein said control unit increases the air flow rate of said cooling fans and at the same time gives an instruction to cut oof power supply to each of said electronic substrates.

15. The electronic apparatus according to claim 1, wherein said predetermined length of time is 1.6 seconds and said predetermined value is 2.0° C.

16. The electronic apparatus according to claim 4, wherein said control unit, after keeping the air flow rate of said plurality of cooling fans increased for a few seconds, again measures the temperature within the case with said plurality of temperature sensors, and determines whether or not to maintain the increase of the air flow rate of said cooling fans on the basis of the result of the measurement.

17. The electronic apparatus according to claim 2, wherein the air flow rate of said cooling fans is increased at least within 10 seconds after the ignition source is inserted into the case.

18. The electronic apparatus according to claim 1, wherein said control unit is installed in a position isolated from said air flow paths.

19. The electronic apparatus according to claim 1, wherein thermal energy of said ignition source is discharged out of the case by increasing the air flow rate of said plurality of cooling fans thereby to prevent the inside of the case from suffering a spread of burning.