JPS598202Y2 - Wind flow detector - Google Patents

Description

[Detailed description of the invention] This invention detects failures in cooling fans built into various devices such as communication equipment, power supply equipment, copy machines, and hot air heaters, or in blowing means such as combustion air blowing fans. Regarding the structure of the detector.

Conventionally, this type of detector consists of a temperature switch 1 which is a combination of a reed switch, a temperature-sensitive ferrite, and a magnet as a magnetic flux source, a heater 2, a substrate 3 made of glass epoxy or kami epoxy, etc., and an eyelet, as shown in Fig. 1. 4, and has a gap 5 between the temperature switch 1 and the heater 2.

When there is a draft in the gap 5, the heat of the heater 2 is not transferred to the temperature switch 1 very much, so the temperature switch 1 is not heated to its operating temperature point and therefore does not operate. When the heater 2 runs out, the heat of the heater 2 is well transferred to the temperature switch 1, and the temperature switch 1 is heated to its operating temperature point and operates, thereby generating a signal to detect an abnormality in the fan.

However, this type of detector has the disadvantage that its operation is affected by wind from other fans.

In other words, if the equipment to which this type of detector is installed is large, it is common to have several or even several 10 fans installed instead of just one fan, so the fan to which the detector is installed may fail. However, if other fans were rotating normally, they would be affected by the wind, causing a delay in the operation time of the detector attached to the failed fan, or in rare cases causing immobility.

Especially when the temperature drops below the ambient temperature, heat conduction becomes poor and this phenomenon becomes more common.

The present invention aims to eliminate or reduce this drawback and provide a highly reliable draft detector.

The present invention will be explained below using examples.

FIGS. 2 to 4 show an embodiment of a draft detector according to the present invention, in which a temperature switch 1 and a heater 2 are connected.
A pair of doors 7 are attached at one end to the base plate 3, which is supported using an eyelet 4, using another relatively long eyelet 6, like a beam fixed at one end.

These doors 7 are made of a flexible thin film with spring properties, and the width near the fixed part is narrowed to make them more flexible, and the main part is located in the gap 5 between the temperature switch 1 and the heater 2. That is, the wide portions correspond and are arranged such that their free ends face each other when not subjected to external forces.

Now, when an external force is applied to the wide part of the door 7, the narrow part mainly bends and opens like a double door, but when the external force is removed, the restoring force of the material returns it to the illustrated position.

Specifically, since the heater 2 is used, such a door 7 is made by punching from a heat-resistant resin film with a thickness of about 10 to 30 microns made of heat-resistant polyester, polyamide, polyamideimide, etc. It is easy to mass produce.

Further, these composite resins have an extremely large restoring force, and have the advantage that their properties are not impaired even when formed into a thin film.

On the other hand, as the material for the eyelet 6, aluminum, brass, nickel plating, or the like is suitable.

The wind flow detector made in this way is placed in a flow path by a fan or the like, as in the conventional case.

At this time, the door 7 may be located on the windward side or on the leeward side, and FIGS. 5 and 6 show the operation in the latter case.

First, Figure 5 shows the situation when the wind speed is higher than the specified value.
In this case, the door 7 is tilted deeply inward due to the wind pressure, and a sufficient amount of air is allowed to pass through the gap 5, thereby detecting that the door is in a normal state.

Now, if the fan to which this detector is attached breaks down and operates at a significantly low speed, or stops altogether and the only flow of air is from other fans, the speed of the wind that is trying to act on this detector decreases. As shown in the figure, the door 7 almost returns to its original state due to its self-restoring force, and since it becomes an obstacle to the flow of air, the amount of ventilation in the gap 5 is significantly reduced, and the temperature switch 1 is heated to the operating temperature point by heat transfer from the heater 2. be done.

Therefore, failure of the fan can be detected reliably.

Needless to say, when there is no wind at all, the conditions shown in Figures 2 to 4 will occur.

In the case of a detector with a specified wind speed of about 5 m/sec, the appropriate thickness of the door 7 is about 10 to 30 microns, but of course the thickness should be selected depending on the wind speed.

FIG. 7 shows the limits of residual wind speed (ie, wind speed from other fans) to which the detector responds at each ambient temperature.

The horizontal axis shows the ambient temperature and the vertical axis shows the wind speed. 8 is the characteristic of the conventional product.

That is, at 0° C., no response occurs if there is a wind speed of 0.8 m/sec or more.

(However, the approximate response time at this time is 300 seconds.
within.

Those that exceeded 3QQ sec were classified as non-responsive.

) At 60°C, it does not respond if the speed is 2.65 m/sec or more.

In other words, the lower part of the curve becomes the response region.

(The experiment is the voltage center value.

That is, normally, the voltage applied to the heater requires a fluctuation range of ±10%, but here, for 100V, 100V was used in the experiment.

) 9 also adopts the characteristics of the present invention.

It can be seen that the wind speed characteristics have been significantly improved.

Assuming that the substrate 3 is placed horizontally, the door 7 may be provided on the upper surface or the lower surface of the substrate 3.

Moreover, although the embodiment in which the door 7 is double-sided has been described above, it goes without saying that the present invention is not limited thereto.

Furthermore, in the above description, the gap 5 between the temperature switch 1 and the heater 2 is
Although we have described a device that detects changes in the air flow based on changes in the amount of air passing through the air, there is no such gap and the change in air flow is detected based on changes in the amount of air around the outer periphery of the combination of the temperature switch 1 and the heater 2. This can also be implemented in the same way by making simple design changes to the shape, dimensions, mounting position, etc. of the door 7.

As explained above using the embodiments, the wind flow detector according to the present invention is provided with a door that automatically obstructs the wind flow that contributes to the operation of the temperature switch when the wind speed decreases, so the operation is reliable. Since the door can be made by punching a thin resin film, it can be provided easily and inexpensively, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a conventional wind flow detector, FIG. 2 is a plan view of an embodiment of the wind flow detector according to the present invention, FIG. 3 is a front view, and FIG. 4 is a bottom view. Figure 5 is a front view showing the situation when a specified flow of air is obtained.
FIG. 6 is a front view showing the situation when the flow of air is insufficient, and FIG. 7 is a graph showing the characteristics of ambient temperature and wind speed. 1...Temperature switch, 2...Heater,
3... Board, 4... Eyelet, 5...
...gap, 6...grommet, 7...
・Door, 8...Characteristic curve of conventional product, 9...
・Characteristic curve of this invention.

Claims (1)

[Scope of utility model registration request] A detector that combines a temperature switch and a heater to detect drafts based on fluctuations in thermal conduction, characterized in that a door made of a flexible thin film with restoring force is provided to face the temperature switch and heater. Detector.