JP2001108880A - Air purge hood - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent entrainment of dust by air discharged from an air discharge port and completely prevent entry into an air purge hood, and dust adheres to a transparent plate. Provide an air purge hood that does not have any. An air passage formed in a state surrounding an outer surface of a transparent plate is connected to a camera case side.
The air discharge port 108 provided in the air passage 105d on the camera case side is separated from the transparent plate
04 is provided at a position close to the plane including the outer surface 104a of the transparent plate 104 so as to surround the outer surface 104a of the transparent plate 104, and the air discharge port 108 is
8 is directed so as to advance in the direction toward the center of the outer surface 104a of the transparent plate 104 along the outer surface 104a of the transparent plate 104, and is provided in the air passage 105c on the front side of the air purge hood. The discharge port 111 is directed toward the front of the front of the air purge hood and away from the air purge hood 105.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a camera case having a transparent plate provided at a position facing a camera lens,
More specifically, the present invention relates to an air purge hood that removes dust from a transparent plate by discharging air, and more particularly, to provide a new air discharge port through which discharged air is directed away from the outer surface of the transparent plate. The present invention relates to an air purge hood with improved effects.

[0002]

2. Description of the Related Art In a conventional ITV monitoring system for monitoring a road or the like, an ITV monitoring system is provided in a space such as a sidewalk beside a roadway.
In many cases, dedicated poles were installed on the poles, and ITV surveillance cameras were installed on the dedicated poles for ITV cameras with fixed heads for monitoring.

When an ITV surveillance camera is installed in an atmosphere where dust is scattered or in an environment with radiant heat, the
In order to protect the TV camera, the ITV surveillance camera is housed in a camera case, a transparent plate is provided on the front of the camera case at a position facing the ITV surveillance camera lens, and the ITV surveillance camera monitors through the transparent plate. .

Further, in order to prevent dust and the like from adhering to the transparent plate of the camera case, an air purge hood is provided in the camera case, and air is blown to the transparent plate, and the dust is scattered by the air pressure.

FIG. 11 is a sectional view showing the flow of air during air purging in a conventional camera case and air purge hood.

FIG. 11 shows an ITV camera 502, a camera lens 503 of the ITV camera 502, and a camera case 50.
1. Outer tubular portion 501a of the camera case, inner tubular portion 501b of the camera case, transparent plate 504, air purge hood 505, outer tubular portion 505a of the air purge hood, inside of the air purge hood fixed to the outer tubular portion 505a. Cylinder 505b, air intake 507, air hose 5
17 is provided.

[0007] An ITV camera (industrial television camera) 502 is housed in a camera case 501, and the camera case 5 facing the lens 503 of the camera 502.
01 is provided with a transparent plate 504 on the front surface. The transparent plate 504 is made of heat-resistant glass, and shuts off external heat to allow light to enter the camera lens 503.

A passage 501c is provided on the inner wall of the camera case 501 so as to surround the camera 502, and cooling water, cooling air, and the like are flowed through the passage, so that the camera 502 is exposed to a high-temperature atmosphere. Even if it is installed, the camera 502 can be used within the operating temperature range.

As described in Japanese Patent Application Laid-Open No. 7-72541, an air purge hood 505 is attached to the front side of the camera case 501. The air purge hood 505 includes an outer cylindrical portion 505a and the outer cylindrical portion 505a. And an inner cylindrical portion 505b fixed to the inner cylindrical portion, and a ring-shaped hollow portion (air passage) 509 is formed by the two cylindrical portions. Then, the air purge hood 505 is attached to the camera case 501 by fixing the flat plate portion 514a of the outer cylindrical portion 505a to the front surface of the camera case,
The inner cylindrical portion 505b is positioned so as to surround the outer surface 504a of the transparent plate 504.

The outer cylindrical portion 505a has an air intake 50
7 is provided, and the air 506 sent out from an air purge device that supplies air such as an air pump is
The air is supplied to the air passage 509 from the air inlet 507. A gap (slit) is formed between the tip 514b of the inner tubular portion 505b and the flat plate portion 514a of the outer tubular portion 505a.
Air discharge port 50 for discharging air 506 inside 9 to the outside
It is 8. Therefore, the air discharge port 508 is located at a position close to a plane including the outer surface 504a of the transparent plate 504, and surrounds the outer surface 504a of the transparent plate 504. The air 506c discharged from the air discharge port 508 is Along the outer surface 504a of the transparent plate 504, it advances to the central portion of the outer surface 504a of the transparent plate 504, and spreads in a direction away from the outer surface 504a of the transparent plate 504 by the pressure of the air 506c itself concentrated at the central portion.

FIG. 12 is a sectional view taken along the line C--C1 in the conventional example.

The sectional view taken along the line C--C1 corresponds to C and C1 in FIG.
Air purge hood 505 with a plane parallel to the transparent plate
12 is a sectional view when the air purge hood 505 is viewed from the direction of the arrow shown in FIG. That is, when the air purge hood 505 is cut along a plane including the discharge port 508 in FIG. 11 and is parallel to the transparent plate 504, the air purge hood 505 is viewed from the arrow direction shown in FIG.

The air 506 supplied from the air inlet 507 spreads in an air passage 509 surrounding the outer surface 504a of the transparent plate 504, and flows from the slit-shaped discharge port 508 toward the center along the outer surface 504a of the transparent plate 504. 506c is formed.

Since the air purge hood 505 has the above-described structure, the outer surface 504 of the transparent plate 504 is blown by the air 506 discharged from the air discharge port 508.
The air layer 506c that travels along a and the air layer 506a that travels while spreading in a direction away from the outer surface 504a of the transparent plate 504 are formed. Therefore, the outer surface 5 of the transparent plate 504
Dust flying on the side of the transparent plate 504 is scattered by an air layer 506c traveling along the outer surface 504a of the transparent plate 504,
Since the air layer 506a spreads in the direction away from the outer surface 504a of the first sheet and spreads in the direction away from the transparent plate 4, dust 512 can be removed and a clear image can be secured.

Since the air layer 506c flows along the outer surface 504a of the transparent plate 504, the transparent plate 504 heated by radiant heat can be cooled by the air layer 506c.

However, in the above-described conventional system, dust 512 on the front surface of the air purge hood 505 is generated by the air discharge port 5.
Since some of the air 506 was discharged from the air 506, dust 512 and the like could not be completely scattered. In addition, the dust 512 sometimes adheres to the transparent plate 4 due to some entrainment, so that the dust 512 needs to be cleaned occasionally although the number of times is small.

[0017]

As described above, in the conventional air purge hood, dust scattered in front of the air purge hood is slightly caught in the air discharged from the air discharge port, and the dust adheres to the transparent plate. And that dust and the like scattered on the front part of the air purge hood cannot be completely removed.

Accordingly, an object of the present invention is to provide an air purge hood that does not cause dust to adhere to a transparent plate and that can completely remove dust scattered on the front portion of the air purge hood. And

[0019]

According to a first aspect of the present invention, there is provided a camera case having a transparent plate provided at a position facing a camera lens and supplied from an air supply unit. In an air purge hood that removes dust and the like attached to the transparent plate by air, the air purge hood is provided near an outer surface of the transparent plate, and supplies the air supplied from the air supply unit along the outer surface of the transparent plate. A first air discharge port for discharging toward the center of the outer surface of the plate; and a first air discharge port provided outside the first air discharge port, for discharging air supplied from the air supply means in a direction away from the outer surface of the transparent plate. And a second air discharge port.

According to a second aspect of the present invention, in the first aspect of the invention, the second air discharge port is a plurality of holes arranged so as to surround the transparent plate. And

According to a third aspect of the present invention, in the first aspect, the second air discharge port is a slit arranged so as to surround the transparent plate.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the second air discharge port is formed by dividing a slit disposed to surround the transparent plate into a predetermined length. It is characterized by a plurality of long holes.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the second air discharge port is configured to surround the transparent plate in a plurality of layers.

According to a sixth aspect of the present invention, in the first aspect of the present invention, a first air passage for conveying air supplied from the air supply means to the first discharge port, A second air passage which conveys the air supplied from the means to the second discharge port.

According to a seventh aspect of the present invention, there is provided a camera case having a transparent plate provided at a position facing a camera lens and removing dust and the like adhered to the transparent plate by air supplied by air supply means. In the air purge hood performing dirt, a dirt detecting means for detecting dirt on the transparent plate, and an air for activating the air supply means when dirt on the transparent plate detected by the dirt detecting means becomes a predetermined amount or more. And supply control means.

According to an eighth aspect of the present invention, in the seventh aspect of the invention, the air supply means is automatically stopped after operating for a predetermined time.

[0027]

FIG. 1 is a view showing a first embodiment of an air purge by an air purge hood according to the present invention.

FIG. 1 shows a camera case 101, an outer cylindrical portion 101a of the camera case, and an inner cylindrical portion 101 of the camera case.
b, ITV camera 102, camera lens 103 of ITV camera, transparent plate 104, air purge hood 105, outer cylindrical portion 105a of air purge hood, outer cylindrical portion 105
a of the inner cylindrical portion of the air purge hood fixed to
b, a partition 114c for partitioning an air passage which is a hollow portion formed by the outer cylindrical portion 105a and the inner cylindrical portion 105b of the air purge hood, and a partition 114c divided into the camera case 101 side and the front side of the air purge hood 105 by the partition 114c. The two air passages, the intake 107b attached to the outer cylinder 105a of the air passage 105d on the camera case 101 side, and the intake 1 attached to the outer cylinder 105a of the air passage 105c on the front side of the air purge hood 105.
07b.

The camera case 101 has the same configuration as the above-mentioned conventional example. In other words, I
The TV camera 102 is housed, and the IT camera 102
A transparent plate 104 is provided on the front surface of the camera case 101 facing the camera lens 103 of the camera case 101, and the outer cylindrical portion 10 of the camera case 101 is provided on the inner wall of the camera case 101.
A hollow portion 101c is formed in a state surrounding the ITV camera 102 by the inner tube portion 1a and the inner cylindrical portion 101b. Cooling water or cooling air is flowed through the hollow portion 101c to use the camera when the camera is installed in a high-temperature atmosphere. The temperature is not allowed to rise above the allowable temperature.

An air purge hood 105 is mounted on the front side of the camera case 101. The air purge hood 105 has an outer tubular portion 105a and an inner tubular portion 105b fixed to the outer tubular portion 105a. The air purge hood 105 is fixed to the camera case 101 by fixing the flat plate portion 114a of the outer cylindrical portion 105a to the front surface of the camera case 101.
05b is installed in a state surrounding the outer surface 104a of the transparent plate 104.

Further, a ring-shaped hollow portion (air passage) is formed by the outer tube portion 105a and the inner tube portion 105b of the air purge hood 105, and the ring-shaped hollow portion (air passage) is purged by air. Divider 114c that divides the front side of the hood 105 and the camera case 101 side
Are fixedly provided to the outer tubular portion 105a and the inner tubular portion 105b. By the partition 114c, two ring-shaped hollow portions, a ring-shaped hollow portion 105c (air passage 105c) on the front side of the air purge hood 105 and a ring-shaped hollow portion 105d (air passage 105d) on the camera case 101 side, are formed. It is formed.

The outer cylindrical portion 105a is provided with two air inlets 107, one of which is provided in the air passage 105c on the front side of the air purge hood 105.
And an inlet 107a for supplying air to the air passage 105d on the camera case 101 side.

The air 106 sent from the air purge device for supplying the air 106 is supplied to an air hose 117.
From the air inlet 107b through the air passage 105c
Then, the air is supplied from the air inlet 107a to the air passage 105d.

A gap (slit) is formed between the distal end 114b of the inner tubular portion 105b of the air purge hood 105 and the flat plate portion 114a of the outer tubular portion 105a, and the slit is formed in the air passage 105d. Air 10
6 is an air discharge port 108 for discharging air to the outside.
Therefore, the air discharge port 108 is connected to the outer surface 10 of the transparent plate 104.
4a and a position close to a plane including the transparent plate 1a.
04, which surrounds the outer surface 104a of the air outlet 104c.
Goes to the central portion of the outer surface 104a of the transparent plate 104 along the outer surface 104a of the transparent plate 104, and the transparent plate 1
The air layer 106a spreads in a direction away from the outer surface 104a of the substrate 04 to form an air layer 106a.

Further, a large number of holes 11 are formed in the inner cylindrical portion 105b of the air passage 105c on the front side of the air purge hood 105.
1 and an air outlet 11 from the air passage 105c.
The air discharged from the air discharge port 111 (a large number of holes) travels in a direction away from the front surface of the air purge hood 105 to form an air layer 106b. still,
The same effect can be obtained by forming the air discharge port 111 in a gap (slit) shape.

Dust 112 and the like floating on the front surface of the transparent plate 104 are scattered from the air layer 106c traveling along the outer surface 104a of the transparent plate 104, and the outer surface 104 of the transparent plate 104
The air flows in a direction discrete from the transparent plate 104 by the air layer 106a spreading in a direction away from the transparent substrate 104. Further, dust or the like 11 floating near the front of the air purge hood 105
2 is completely sent out of the air purge hood 105 by the air layer 106b that moves away from the front of the air purge hood 105 even if it attempts to enter the air purge hood 105. Therefore, the dust 112 does not adhere to the outer surface 104a of the transparent plate 104. In addition, a clear image can be provided without the occurrence of a winding phenomenon.

FIG. 2 is a sectional view taken along line AA1 of FIG.

A section taken along the line A-A1 means that the air purge hood 105 is cut along a plane connecting A and A1 in FIG. 1 and parallel to the transparent plate, and the air purge hood 10 is cut in the direction of the arrow shown in FIG.
FIG. 5 is a sectional view when viewing FIG. That is, when the air purge hood 105 is cut on a plane parallel to the transparent plate 104 and including the air passage 105c in FIG. 1, it is a cross-sectional view when the air purge hood 105 is viewed from the arrow direction shown in FIG.

A large number of discharge ports 111 provided in the inner cylindrical portion 105b of the air passage 105c so as to surround the transparent plate 104 can scatter dust and the like 112 floating on the front of the air purge hood 105. it can.

FIG. 3 is a sectional view taken along line A2-A3 in FIG.

The sectional view taken along the line A2-A3 corresponds to A2 and A2 in FIG.
3 is a cross-sectional view when the air purge hood 105 is cut along a plane parallel to the transparent plate 104 and the air purge hood 105 is viewed from the direction of the arrow shown in FIG. 1. That is, the air passage 10 between the partition 114c and the intake 107b in FIG.
FIG. 2 is a cross-sectional view when the air purge hood 105 is viewed from the direction of the arrow shown in FIG.

The tip 1 of the inner cylindrical portion of the air passage 105d
14b and a slit-shaped discharge port 108 between the outer tubular portion 114a and the outer surface 10 of the transparent plate.
By providing the air layer 4a in a state surrounding the air layer 4a, the air discharged from the discharge port 108 moves toward the center along the outer surface 104a of the transparent plate 104 as shown in FIG.
06c is formed, and dust 112 and the like 112 attached to the outer surface 104a of the transparent plate 104 and dust 112 and the like floating near the transparent plate 104 can be removed.

FIG. 4 is a view showing a second embodiment of the air purge by the air purge hood according to the present invention.

In FIG. 4, in addition to the air discharge port 211 corresponding to the air discharge port 111 of the first embodiment, another one is provided in the inner cylindrical portion 205b of the air passage 205c on the front side of the air purge hood 205. This is an example in which air outlets 211a (many holes) similar to one outlet 211 are provided.

Dust floating at the end of the front surface of the air purge hood 205 also scatters in a direction away from the air purge hood 205 in the air layer 206b discharged from the provided air discharge port 211a, and further the dust 212 and the like. It can be scattered efficiently.

At this time, the air discharge ports 211, 21
1a may be located at the position of the air discharge ports 211c and 211d.

The discharge ports 211, 211a, 211c, 21
The shape 1d has the same effect even in the shape of a gap (slit).

FIG. 5 is a view showing a third embodiment of an air purge means using an air purge hood according to the present invention.

FIG. 6 is a sectional view taken along line BB1 of FIG.

The sectional view taken along the line B-B1 is a plane which connects B and B1 in FIG.
FIG. 6 is a cross-sectional view when the air purge hood 305 is viewed from the direction of the arrow shown in FIG. That is, the air passage 305c between the partition 314c and the inlet 307b in FIG.
FIG. 6 is a cross-sectional view when the air purge hood 305 is viewed from the direction of the arrow shown in FIG. 5 when the air purge hood 305 is cut along a plane parallel to the transparent plate 304.

As shown in FIG. 6, by providing the partitions 308a to 308h in the slit-shaped discharge ports 311 in FIG. 3, elongated air discharge ports 311a to 311h are formed.

The air discharge ports are connected to the air discharge sections 311a-311.
The air pressure can be increased from the slit-shaped discharge port 311 shown in FIG. Other configurations and effects are the same as those of the first embodiment.

FIG. 7 is a view showing a fourth embodiment of the air purge by the air purge hood according to the present invention.

This embodiment is an embodiment in which the partition 214c for dividing the air passage in the second embodiment is not provided, the air passage is made one, and the air intake is made one. The positions of the discharge ports 411 and 411a are
The same effect can be obtained with the positions 1c and 411d.

As disclosed in Japanese Patent Application Laid-Open No. 7-72541, means for increasing the slit width as the distance from the air inlet increases, means for decreasing the hole pitch as the distance from the air inlet increases, and air as the distance from the air intake increases. By using a means to increase the diameter of the discharge port, the flow rate of air discharged from the air discharge port near the air inlet where the air pressure is strong, and the air discharged from the portion of the air discharge port where the air pressure is weakened away from the air inlet The flow rate of the drawn air can be made substantially the same.

In the first embodiment shown in FIG.
The air passage was divided into two by c, and the air intakes 107a and 107b were provided for each of the divided air passages.
A plurality of partitions 114c may be used to divide the air passage into three or more, and an air intake may be provided in each of the divided air passages. This is similarly applied to the second embodiment of FIG. 4 and the third embodiment of FIG.

Although two second discharge ports are provided in the second embodiment of FIG. 4, three or more second discharge ports may be provided. This also applies to the fourth embodiment shown in FIG.

In the fourth embodiment shown in FIG. 7, two or more air inlets 407 may be provided.

In the above example, the case where the transparent plate is circular and the air purge hood is cylindrical has been described.
The same applies to the case where the transparent plate is square and the air purge hood is a square pillar.The shape of the transparent plate and the shape of the air purge hood are not limited to those described above as long as the transparent plate can be surrounded by the air purge hood. Any shape is acceptable.

In the above, emphasis has been placed on the air purge hood, and the air purge means for dust and the like in the air purge hood has been described.

Next, a method of detecting when the amount of dust or the like adhering to the transparent plate becomes a certain amount or more and automatically operating an air purge device to perform air purging of the transparent plate will be described.

This is because it is not economical to always operate the air purge device in an environment where there is little dust or the like floating on the front of the air purge hood or adhering to the transparent plate. An air purge device is operated when air purge is required by detecting a predetermined amount or more of dust or the like that hinders an image.

FIG. 8 is a structural view showing the structure of the air purge monitoring camera device according to the present invention.

FIG. 8 shows a camera case 601, an ITV surveillance camera 602 accommodated in the camera case, a camera lens 603 of the ITV surveillance camera, and a transparent plate fixed to the front of the camera case 601 facing the ITV surveillance camera lens 603. 604, air purge device 61 for supplying air
6. An air purge hood 605 fixed to the front surface of the camera case 601; an intake 607 for taking in air supplied from the air purge device 616; Focus on the air hose 617 and the transparent plate 604 which are the paths of the supplied air,
Sensor 61 for detecting dust and the like attached to transparent plate 604
8. It is provided with a cable 619 for transmitting the detection signal of the sensor to the air purge device.

The air purge hood 605 shown in FIG.
The same applies to the structure of the air purge hood in FIGS. 1 to 7, 11 and 12, and FIG. 8 shows an example of one air inlet.

An air purge hood 605 is fixed to the camera case 601 containing the ITV camera 602, and an air purge device 616 for supplying air to the air purge hood 605 is fixed to the rear of the camera case 601. The air purge device 616 is provided with a drive unit such as a motor, and the drive unit operates to supply air. The air hose 6 extends from the air purge device 616 to the intake 607 of the air purge hood 605.
The air supplied from the air purge device 616 via the air hose 617 is sent to the intake 607 of the air purge hood 605.

Further, inside the camera case 601, a dirt detection sensor 618 for detecting dirt on the transparent plate 604 fixed to the front of the camera case 601 is provided.
From the dirt detection sensor 618, the air purge device 61
6 is connected to the cable 619 and the dirt detection sensor 61 is connected.
The detection signal at 8 is transmitted to the air purge device 616.

FIG. 9 is a structural view showing a state before the air purge near the transparent plate in front of the camera case.

When a certain amount or more of dirt such as dust adheres to the transparent plate 604, the dirt detection sensor 618 detects the dirt and the detected signal is transmitted to the cable 619.
Is transmitted to the air purge device 616 via the.

FIG. 10 is a flowchart showing a procedure for detecting the dirt on the transparent plate by the dirt detection sensor and performing an air purge operation.

In FIG. 10, the dirt detection sensor 618
Is set so as to focus on the transparent plate 604 of the camera case 601 and monitors the dirt on the transparent plate 604 (step 701).

When the dirt on the transparent plate 604 exceeds a certain value, the dirt detecting sensor 618 detects the dirt (YES in step 702), and drives the driving section of the air purge device 616 via the cable 619 to the air purge device 616. An activation signal for activation is transmitted (step 703).

When the stain on the transparent plate 604 does not reach the predetermined value, the stain detection sensor 618 monitors whether the stain on the transparent plate 604 exceeds a certain value (N in step 702).
O).

The operation signal transmitted from the dirt detection sensor 618 to the air purge device 616 is
Then, the drive unit of the air purge device 616 is operated to supply air to the intake 607 of the air purge hood 605 via the air hose 617 (step 704).

When air is supplied to the air purge hood inlet 607, an air layer is formed as described above, and dust 612 or the like of the transparent plate 604 is scattered (step 70).
5).

The time is set by a timer or the like, air purge is performed for a certain period of time (step 706), the air purge device 616 is stopped (step 707), and a dirt detection sensor detects that dust or the like 612 adheres to a certain amount or more. Monitor again at 618.

Thereafter, if the environment around the air purge hood 605 is large in dust and the like 612, the dust and the like 612
Adheres to the transparent plate 604, and the dirt on the transparent plate 604 is detected by the dirt detection sensor 618, and the air purge device 616 is operated again to perform air purging.

If the environment in which the amount of dust 612 is large is temporary and the amount of dust 612 is small at present, the dust 612 having a certain value or more does not adhere to the transparent plate 604, and the air purge device 616 operates. do not do.

As described above, a certain amount or more of the transparent plate 6
04 is automatically detected and the air purge hood 60
5 is supplied with air, the dust 612 or the like does not adhere to the transparent plate 604, and the air purge device 61
6 is economical because it does not keep running.

[0080]

As described above, according to the present invention,
By forming an air layer that advances to the center along the outer surface of the transparent plate, an air layer that spreads away from the outer surface of the transparent plate, and an air layer that advances forward from the front of the air purge hood Dust and the like floating on the front side of the transparent plate are scattered by the air layer traveling away from the front side of the transparent plate. Also, if dust or the like floating near the front of the air purge hood attempts to enter the inside of the air purge hood, the air layer discharged from the air discharge port provided on the front of the air purge hood completely removes the dust and the like. It can be scattered and completely prevented from entering the air purge hood. Therefore, dust and the like do not adhere to the transparent plate.

Further, by automatically detecting dust and the like adhering to the transparent plate by the dirt detection sensor and operating the air purging device, the air purging device is operated in a state where a certain amount of dust and the like does not adhere to the transparent plate. The efficiency and economy of the operation of the air purge device can be improved without being continued.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of an air purging means using an air purge hood according to the present invention.

FIG. 2 is a sectional view taken along line AA1 of FIG.

FIG. 3 is a sectional view taken along line A2-A3 of FIG.

FIG. 4 is a view showing a second embodiment of the air purging by the air purge hood according to the present invention.

FIG. 5 is a view showing a third embodiment of the air purge by the air purge hood according to the present invention.

FIG. 6 is a sectional view taken along line BB1 of FIG. 5;

FIG. 7 is a view showing a fourth embodiment of the air purging by the air purge hood according to the present invention.

FIG. 8 is a structural diagram showing a structure of an air purge monitoring camera device according to the present invention.

FIG. 9 is a structural diagram showing a situation before air purging near a transparent plate in front of a camera case 4;

FIG. 10 is a flowchart showing a procedure for detecting dirt on the transparent plate by a dirt detection sensor and performing an air purge operation.

FIG. 11 is a structural view showing the flow of air at the time of air purging in a conventional camera case and air purging hood.

FIG. 12 is a cross-sectional view taken along the line C-C1 in FIG. 11 of a conventional example.

[Explanation of symbols]

 101 camera case 101a camera case outer tube 101b camera case inner tube 101c hollow 102 ITV surveillance camera 103 ITV surveillance camera lens 104 transparent plate 104a transparent plate outer surface 105 air purge hood 105a air purge hood outer tube 105b inside air purge hood Cylinder 105c Air purge hood front side air passage 105d Camera case side air passage 106 Air 107 intake 107a Camera case side intake 107b Air purge hood front side intake 108 Discharge port 111 Air purge hood front part discharge port 112 Dust, etc. 114a Flat portion of outer cylinder of air purge hood 114b Tip of inner cylinder of air purge hood 114c Partition 616 Air purge device 617 Air hose 618 Soil Detection sensor 619 cable

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideaki Enomoto 3-1-1 Asahigaoka, Hino-shi, Tokyo F-term in Toshiba Hino Factory Co., Ltd. 2H044 AD03 2H100 EE06

Claims (8)

[Claims] 1. An air purge hood fixed to a camera case having a transparent plate provided at a position facing a camera lens and removing dust and the like attached to the transparent plate by air supplied from an air supply means, A first air discharge port provided near the outer surface of the transparent plate and for discharging air supplied from the air supply means along the outer surface of the transparent plate toward the center of the outer surface of the transparent plate; And a second air discharge port provided outside the air discharge port for discharging the air supplied from the air supply means in a direction away from the outer surface of the transparent plate. 2. The air purge hood according to claim 1, wherein said second air discharge port is a plurality of holes arranged so as to surround said transparent plate. 3. The air purge hood according to claim 1, wherein the second air discharge port is a slit disposed so as to surround the transparent plate. 4. The air outlet according to claim 1, wherein the second air discharge port is a plurality of slots formed by dividing a slit disposed to surround the transparent plate into a predetermined length. Air purge hood. 5. The air purge hood according to claim 1, wherein the second air discharge port is configured to surround the transparent plate in a plurality of layers. 6. A first air passage for conveying air supplied from the air supply means to the first discharge port, and conveying air supplied from the air supply means to the second discharge port. The air purge hood according to claim 1, further comprising a second air passage. 7. An air purge hood fixed to a camera case having a transparent plate provided at a position facing a camera lens and removing dust and the like attached to the transparent plate by air supplied by air supply means, A dirt detection means for detecting dirt on the transparent plate; and air supply control means for operating the air supply means when the dirt on the transparent plate detected by the dirt detection means has exceeded a predetermined amount. An air purge hood characterized by the following. 8. The air purge hood according to claim 7, wherein said air supply means automatically stops after operating for a predetermined time.