JP2008140796A - Base station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base station having no possibility that an insect or dust intrudes into the housing to cause damage on the electric circuit, and in which the possibility of igniting hydrogen gas can be prevented even if water is generated in the housing due to variation in climatic conditions and hydrogen gas is produced through electrolysis of that water. <P>SOLUTION: In the base station 1 installed outdoors while containing the electric circuit in the housing 11, intrusion of an insect or dust into the housing 11 is prevented by employing an enclosed housing 11. Furthermore, mechanical atmospheric pressure regulation valves 31 and 32 for sustaining the atmospheric pressure in the housing 11 below a predetermined level by releasing the pressure to the outside are provided. When the internal pressure of the housing 11 is boosted through electrolysis of water generated in the housing 11, internal gas is discharged to the outside by the mechanical atmospheric pressure regulation valves 31 and 32 in order to lower the hydrogen concentration in the housing 11, thus avoiding the possibility of igniting hydrogen gas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a base station of a wireless communication system in which an electric circuit is accommodated in a sealed casing and is installed outdoors.

  A base station that relays radio waves from a wireless communication system such as a mobile phone or a PHS accommodates electric circuits and power sources necessary for relaying and allocating radio waves in a waterproof enclosure and installed outdoors. Installed.

  As such a base station, the bottom of the casing or the like has a breathing hole that is always open, an inclined part that effectively condenses moisture in the outside air that has entered the casing through the breathing hole, and a condensing part at the inclined part. Has been developed that has a drain outlet installed near the position where the water drops are dropped, and a valve body that opens the drain outlet by buoyancy received from the water when a certain amount of water accumulates around the drain outlet. (For example, refer to Patent Document 1).

In such a base station, it is possible to prevent moisture in the outside air that has entered the housing from the breathing hole from adhering to the electric circuit inside the housing.
However, if there is a breathing hole, there is a risk that small insects and fine dust that have entered through the breathing hole will adhere to the electric circuit in the housing, causing damage to the electric circuit.

  Therefore, a base station in which the breathing hole is eliminated from the housing and the housing is sealed is studied. This is because by making the casing hermetically sealed, insects and dust can be prevented from entering the casing.

JP-A-6-77669

By the way, as described in Patent Document 1, even if the structure is provided with an inclined portion that effectively condenses moisture in the outside air that enters from the breathing hole of the housing, or the housing is sealed, The moisture in the air that has entered the housing from the inside may condense due to fluctuations in the surrounding weather conditions, and it is not possible to completely prevent moisture from adhering to the electrical circuit in the housing.
When moisture adheres to the electric circuit, if the electric circuit is a circuit in which a direct current flows, the adhering moisture is electrolyzed, and the water adhering to the electrolysis is decomposed into hydrogen gas and oxygen gas. Is done.
In the case of a sealed housing, each gas generated by electrolysis is trapped in the housing, so when the hydrogen gas concentration exceeds a certain level, there are electrical contacts in the housing and places that are short-circuited by water. There is a risk of ignition of hydrogen gas due to generated sparks or the like.

Therefore, in order to prevent the occurrence of such a situation, a water sensor that detects the generation of water in the casing is provided in the casing, and when the water sensor detects the generation of water, the base station It was considered to notify the management device by wireless transmission. Furthermore, it is desirable to quickly stop the power supply to each electric circuit in the housing to prevent the occurrence of electrolysis itself.
In this case, when the notification of the generation of water is received, the maintenance worker of the corresponding base station removes the water inside the base station and then restores the power supply.
However, such a response is not practical because the base station has been disabled for a long time until power supply is restored.

  Therefore, an object of the present invention is to solve the above-mentioned problems, and there is no possibility that insects or dust may enter the housing and cause damage to the electric circuit in the housing. Even if water is generated in the body, the risk of ignition of hydrogen gas generated by electrolysis of the water can be avoided, and furthermore, the power supply stop period due to the generation of water in the housing is minimized. It is possible to provide a base station that can operate stably for a longer period of time.

  A base station according to the present invention is a base station that is installed outdoors with an electric circuit housed in a sealed casing, and when the atmospheric pressure in the casing is increased to a predetermined level or more in the sealed casing, A mechanical air pressure adjusting valve is provided to release the pressure to the outside and maintain the air pressure in the housing at a predetermined value or less (claim 1).

According to the above configuration, since a sealed casing is used, there is no possibility that insects or dust may enter the casing and cause rust, damage, short circuit, or the like in the electric circuit in the casing.
Also, even if water is generated in the case due to changes in weather conditions, etc., and oxygen gas and hydrogen gas are generated by electrolysis of the water, the pressure in the case is set to a predetermined value by the generation of these gases. When the pressure reaches the value, the mechanical pressure control valve is activated to release the gas in the housing.
Therefore, even if water electrolysis occurs in the housing, it is possible to prevent the hydrogen gas concentration from rapidly increasing in the housing and avoid the risk of ignition of hydrogen gas.
In addition, even if water electrolysis occurs in the housing, the mechanical pressure control valve can avoid the risk of ignition of hydrogen gas, so power supply is immediately stopped even if water is detected in the housing. There is no need. For example, when power supply is stopped, after the generation of water is detected, even if the mechanical pressure control valve is operated, hydrogen gas cannot be sufficiently discharged and the pressure inside the housing cannot be improved. Usually, maintenance and repair work is carried out before the power supply stops, etc., so that the power supply stop period due to water generation in the housing can be minimized. The base station can be stably operated for a longer period of time.

Further, a plurality of the mechanical pressure control valves are provided (claim 2).
With this configuration, even if some mechanical pressure control valves fail, other mechanical pressure control valves operate, improving the reliability of the pressure reduction operation by the mechanical pressure control valves. Can be made.
In addition, by changing the operating pressure of multiple mechanical pressure control valves little by little, it is possible to simultaneously operate a number of mechanical pressure control valves when the pressure inside the housing is abrupt due to water electrolysis. By doing so, pressure reduction can be realized in a shorter time, and exhaust processing by the mechanical pressure control valve can be speeded up.

Further, a water sensor for detecting moisture remaining inside the casing is provided in the sealed casing,
When the water sensor detects water, a control circuit that monitors the detection signal of the water sensor notifies the base station management device to that effect (claim 3).
With such a configuration, the base station management device can quickly detect the occurrence of water in the housing, and the possibility of ignition of hydrogen gas by exhausting with the mechanical pressure control valve equipped in the base station. If a maintenance worker can be dispatched to the base station while avoiding the situation, the water in the base station can be quickly removed to prevent the power supply from being stopped at the base station, or the power supply can be stopped. Occurrence period can be minimized.

In addition, a pressure sensor that detects the pressure inside the casing is provided in the sealed casing, and a control circuit that monitors a detection signal of the pressure sensor is provided when the pressure in the casing is increased to a predetermined value or more. When the pressure is reduced to a specified value or less after the pressure increase, the fact is notified to the base station management device (claim 4).
With such a configuration, a maintenance worker who knows the occurrence of water in the housing and goes out to perform maintenance work on the base station to remove the water is notified by the progress notification based on the detection signal of the pressure sensor. It is possible to more accurately infer the state and progress of electrolysis of water in the water, and to work more safely.

In addition, when the water sensor detects water and the pressure sensor continuously detects a pressure higher than a specified value and detects a predetermined time or more, the control circuit that monitors detection signals of the water sensor and the pressure sensor, The power supply from the power supply in the housing to each electric circuit is stopped (Claim 5).
With such a configuration, even if the arrival of a maintenance worker is delayed, the occurrence of ignition of hydrogen gas can be prevented in advance, and the safety of work can be ensured.

In the base station according to the present invention, since a sealed casing is used, there is no possibility that insects or dust may enter the casing and cause rust, damage, short circuit, etc. in the electrical circuit in the casing.
Also, even if water is generated in the case due to changes in weather conditions, etc., and oxygen gas and hydrogen gas are generated by electrolysis of the water, the pressure in the case is set to a predetermined value by the generation of these gases. When the pressure reaches the value, the mechanical pressure control valve is activated to release the gas in the housing.
Therefore, even if water electrolysis occurs in the housing, it is possible to prevent the hydrogen gas concentration from rapidly increasing in the housing and avoid the possibility of ignition of hydrogen gas.
In addition, even if water electrolysis occurs in the housing, the possibility of ignition to hydrogen gas can be avoided by the mechanical pressure control valve, so power supply is stopped immediately even if water is detected in the housing. do not have to. For example, when power supply is stopped, after the generation of water is detected, even if the mechanical pressure control valve is operated, hydrogen gas cannot be sufficiently discharged and the pressure inside the housing cannot be improved. Usually, maintenance and repair work is carried out before the power supply stops, etc., so that the power supply stop period due to the generation of water in the housing can be minimized. The base station can be operated stably for a longer period.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a housing for outdoor installation according to the invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an embodiment of a base station according to the present invention, FIG. 2 is a perspective view of the base station shown in FIG. 1 as viewed obliquely from above, and FIG. 3 is a base station shown in FIG. It is explanatory drawing of the pressure reduction process by the mechanical type | formula atmospheric pressure regulation valve with which the housing | casing was equipped.

The base station 1 according to this embodiment is installed outdoors as a base station that relays radio waves from a mobile phone. A sealed circuit housing space 13 that houses an electric circuit or the like necessary for the base station has a housing. Provided by body 11.
The casing 11 is a so-called sealed type having no breathing hole or the like, and is constituted by two case members 15 and 16 that are connected to each other by abutting the connection end faces 15a and 16a.

The first case member 15 has a box shape with one side open, and a plurality of antenna connection portions 17 for connecting transmission / reception antennas are provided on the upper wall 15b. Further, the first case member 15 is equipped with an RF unit 18 that is an electric circuit that performs transmission / reception processing of radio waves and a digital processing unit 19 that is an electric circuit that digitizes signals.
The open end surface of the first case member 15 is provided with the connection end surface 15a by a flange portion 15c protruding to the outer peripheral side.

The second case member 16 has a box-shaped structure with one side faced with the first case member 15 being opened. In the second case member 16, a power supply circuit 21 for supplying predetermined power to each electric circuit or the like in the first case member 15 and an external power supply cable for operating the power supply circuit 21 are provided. Are connected to the power supply terminal 22 and the like.
A connection end surface 16 a that is abutted against the connection end surface 15 a of the first case member 15 is provided on one open side surface of the second case member 16 by a flange portion 16 c that projects to the outer peripheral side.

  The case members 15 and 16 are fixed to each other by fastening the flange portions 15c and 16c with screws 24 in a state in which the connection end faces 15a and 16a are abutted with each other. 13 is defined.

As shown in FIG. 1, moisture that has entered between the connection end faces 15 a and 16 a from the outside enters the circuit housing space 13 between the connection end faces 15 a and 16 a that face each other. A waterproof packing 26 is provided to prevent this.
In the case of the present embodiment, the waterproof packing 26 is accommodated in a packing accommodation groove 15d formed in the flange portion 15c.

In the case of the present embodiment, when the atmospheric pressure in the casing 11 is increased to a predetermined level or more, the second case member 16 constituting the casing 11 releases the pressure to the outside, and the atmospheric pressure in the casing 11 is increased. A plurality of mechanical pressure control valves 31 and 32 that are maintained below a predetermined value are provided.
These mechanical atmospheric pressure adjusting valves 31 and 32 are both general mechanical atmospheric pressure adjusting valves that operate by spring elasticity. The operating pressure can be changed by adjusting the built-in spring load.

Of the two mechanical pressure control valves 31 and 32, one mechanical pressure control valve 31 is provided on the bottom wall of the second case member 16. The other mechanical pressure adjustment valve 32 is provided on the ceiling wall of the second case member 16.
In this way, by disposing the plurality of mechanical pressure control valves 31 and 32 in a vertically dispersed manner, whether the pressure increase due to the electrolysis of water occurs in either the upper part or the lower part in the circuit accommodating space 13, The pressure can be reduced quickly.
Further, the hydrogen gas generated by the electrolysis of water has a small specific gravity and is stored in the upper part of the circuit housing space 13. Therefore, it is effective to prevent the ignition of the hydrogen gas by equipping the upper part with the mechanical pressure control valve so that the hydrogen gas can be exhausted with priority.

The operating pressures of the mechanical pressure control valves 31 and 32 are determined by estimating the pressure before the hydrogen concentration in the circuit housing space 13 reaches a concentration at which explosion or ignition is likely to occur.
Specifically, the hydrogen concentration at which hydrogen gas easily causes explosion or ignition is 5% to 30%. The pressure at which this hydrogen concentration is reached is estimated to be 109431 pa to 184411 pa (1.08 atm to 1.82 atm).

  In the present embodiment, two mechanical pressure control valves 31 and 32 are provided. However, the number of mechanical pressure control valves provided in the housing 11 is determined by the capacity of the circuit housing space 13 and the like. It may be set corresponding to the assumed pressure rise, and depending on the assumed pressure rise, it is conceivable to set the number of mechanical pressure control valves to a single or a plurality of three or more.

  Further, in the base station 1 of the present embodiment, a water sensor 34 that detects moisture remaining in the housing 11, a pressure sensor 36 that detects atmospheric pressure in the housing, and each of these sensors in the housing 11. A control circuit 38 that performs a predetermined control operation based on the detection signal is provided.

As the water sensor 34, for example, a sensor that irradiates infrared rays or laser light and optically detects moisture, and various humidity sensors can be used. For example, as a humidity sensor, there is a polymer film humidity sensor that measures humidity from a change in dielectric constant accompanying absorption and absorption of moisture in the polymer film. Changes and impedance changes are converted into electrical signals and output. In the case of a humidity sensor, water (moisture) may be detected when the humidity is very high (for example, the humidity is 90% or more).
In the circuit housing space 13 shown in FIG. 1, since water naturally accumulates from the bottom of the housing 11, it is preferable that the water sensor 34 be disposed below. Or it is also preferable to arrange | position in the vicinity of the circuit through which a direct current flows, an electrical contact, a power supply, etc. Moreover, you may arrange | position the water sensor 34 in these multiple places.

  The pressure sensor 36 detects the pressure in the housing as follows. A pressure sensor is a semiconductor strain gauge formed on the surface of a diaphragm, and converts an electrical resistance change due to a piezo effect generated when the diaphragm is deformed into an electric signal by an external force (pressure). .

  The control circuit 38 monitors the detection signals of the water sensor 34 and the pressure sensor 36. When the water sensor 34 detects water, the control circuit 38 notifies the base station management device by wireless communication from the RF unit 18. Further, the control circuit 38 indicates that when the pressure in the housing 11 is increased to a specified value or more based on the detection signal of the pressure sensor 36, and when the pressure is reduced to a specified value or less after the pressure increase. Is notified to the base station management apparatus by wireless communication from the RF unit 18.

  Furthermore, the control circuit 38 of the present embodiment is configured such that the mechanical pressure adjustment valve 31 is detected when the water sensor 34 detects water and the pressure sensor 36 continues to increase the pressure above a specified value for a predetermined time or longer. , 32 are not functioning properly, or the electrolysis of water is activated more than expected and requires urgency, and the power supply (power supply circuit 21) in the housing 11 is connected to each electric circuit. Stop power supply. This is to prevent sparks generated by the switching operation of the circuit contacts in a power supply state or a location shorted by water from igniting hydrogen gas.

  Even if the water sensor 34 detects water, the control circuit 38 supplies power to each electric circuit when the pressure increase state above the specified value detected by the pressure sensor 36 falls below the specified value within a certain time. Do not stop.

In the base station 1, the procedure for operating the mechanical pressure regulating valves 31, 32 is as shown in FIG.
In an appropriate operating situation in which the water sensor 34 does not detect water and the pressure sensor 36 does not detect an increase in pressure, as shown in FIG. 3 (a), the mechanical pressure regulating valves 31, 32 close the flow path. Maintained.
As shown in FIG. 3B, when water enters the housing 11, the water sensor 34 detects it. Based on the detection signal of the water sensor 34, the control circuit 38 notifies the base station management device to that effect by radio.
When water that has entered the casing 11 touches the direct current of the internal circuit and electrolysis of the water begins, as shown in FIG. 3C, the casing 11 generates hydrogen gas and oxygen gas. Inside pressure begins to rise.
Then, when the pressure in the casing 11 is increased to a specified value, the control circuit 38 notifies the base station management device wirelessly based on the detection signal of the pressure sensor 36 as shown in FIG. Notice.
Next, as shown in FIG. 3 (e), in order to eliminate the pressure increase, the mechanical pressure adjusting valves 31, 32 open the flow path and discharge the gas in the housing 11 to the outside.
When the pressure in the housing 11 drops below a predetermined value due to the discharge of gas due to the operation of the mechanical pressure adjustment valves 31, 32, the mechanical pressure adjustment valves 31, 32 close the flow path, The control circuit 38 notifies that the pressure has been reduced to a predetermined value or less, and returns to the state of FIG.

In the base station 1 of the present embodiment described above, since the sealed casing 11 is used, insects and dust enter the casing 11 and cause damage to the electric circuit in the casing 11. There is no fear.
In addition, even if water is generated in the casing 11 due to changes in weather conditions or the like, and oxygen gas and hydrogen gas are generated by electrolysis of the water, the generation of these gases in the casing 11 When the pressure reaches a predetermined value, as shown in FIG. 3 (e), the mechanical pressure adjustment valves 31 and 32 are operated to release the gas in the housing 11.
Therefore, even if water electrolysis occurs in the housing 11, it is possible to prevent the hydrogen gas concentration from rapidly increasing in the housing 11 and avoid the possibility of ignition of hydrogen gas.

  In addition, even if water electrolysis occurs in the housing 11, the possibility of igniting hydrogen gas can be avoided by the mechanical pressure control valves 31, 32, so that the occurrence of water in the housing 11 is detected. However, it is not necessary to stop power supply immediately. For example, in stopping the power supply, after detecting the generation of water, the operation of the mechanical pressure adjustment valves 31 and 32 cannot sufficiently achieve the discharge of hydrogen gas, and the pressure increase in the housing 11 cannot be improved. It is limited only to such a situation, and normally, maintenance / repair work is carried out before falling into a situation where boosting cannot be improved, so that the power supply caused by the generation of water in the housing 11 is performed. The outage period can be minimized and the base station can be stably operated for a longer period.

Furthermore, since the base station 1 of the present embodiment is equipped with two mechanical pressure control valves 31, 32, even if one mechanical pressure control valve fails, another mechanical pressure control By operating the regulating valve, it is possible to improve the reliability of the pressure reducing operation by the mechanical pressure regulating valve.
Moreover, when the operating pressures of the two mechanical pressure control valves 31 and 32 are gradually changed and equipped, when the pressure inside the casing 11 due to water electrolysis is abrupt, both mechanical pressures By simultaneously operating the regulating valves 31 and 32, it is possible to reduce the pressure in a shorter time, and it is possible to speed up the exhaust process by the mechanical pressure regulating valves 31 and 32.

  Further, the base station 1 of the present embodiment includes a water sensor 34 that detects moisture remaining inside the casing 11 in the sealed casing 11, and when the water sensor 34 detects water, The control circuit 38 that monitors the detection signal 34 notifies the base station management apparatus accordingly. Therefore, the generation of water in the casing 11 can be known at an early stage by the base station management device, and the occurrence of ignition of hydrogen gas is avoided by exhausting by the mechanical pressure control valves 31 and 32 equipped in the base station. If a maintenance worker can be dispatched to the base station during the operation, the water in the base station can be quickly removed to prevent the power supply from being stopped at the base station, The generation period can be minimized.

Further, in the base station 1 of the present embodiment, a pressure sensor 36 that detects the atmospheric pressure in the casing 11 is provided in the sealed casing 11, and a control circuit 38 that monitors the detection signal of the pressure sensor 36 is provided. When the pressure in the casing 11 is increased to a specified value or higher, or when the pressure in the casing 11 is reduced to a specified value or lower after the pressure increase, the base station management apparatus is notified.
Therefore, a maintenance worker who knows the occurrence of water in the housing 11 and goes out to perform maintenance work on the base station to remove the water can notify the inside of the base station based on the progress notification based on the detection signal of the pressure sensor 36. It is possible to more accurately infer the occurrence and progress of water electrolysis, and to work more safely.

Further, in the base station 1 of the present embodiment, when the water sensor 34 detects water and the pressure sensor 36 continues to increase the pressure above a specified value and detects a predetermined time or more, the water sensor 34 and The control circuit 38 that monitors the detection signal of the pressure sensor 36 stops power supply from the power source in the housing 11 to each electric circuit.
Therefore, even when the arrival of the maintenance worker is delayed, the occurrence of ignition of hydrogen gas can be prevented in advance, and the safety of work can be ensured.

  In the base station according to the present invention, the number of case members constituting the sealed casing 11 is not limited to the above embodiment. For example, the casing 11 of the above-described embodiment is configured by two case members. However, the circuit housing space having a predetermined volume is formed by connecting and connecting three or more case members. There may be.

It is a longitudinal cross-sectional view of one embodiment of the base station according to the present invention. It is the perspective view seen from diagonally upward of the base station shown in FIG. FIG. 3 is an explanatory diagram of pressure reduction processing by mechanical atmospheric pressure adjustment valves 31 and 32 mounted on a housing 11 in the base station shown in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Housing | casing 13 Circuit accommodation space 15 1st case member 15a Connection end surface 15c Flange part 16 2nd case member 16a Connection end surface 16c Flange part 18 RF part 21 Power supply circuit 22 Power supply terminal 24 Screw 26 Waterproof packing 31, 32 Machine Pressure control valve 34 Water sensor 36 Pressure sensor 38 Control circuit

Claims (5)

A base station of a wireless communication system that is installed outdoors with an electric circuit housed in a sealed casing,
The sealed casing is provided with a mechanical pressure adjustment valve that releases the pressure to maintain the atmospheric pressure in the casing below a predetermined value when the atmospheric pressure in the casing rises above a predetermined level. base station.   The base station according to claim 1, wherein a plurality of the mechanical pressure control valves are provided. A water sensor for detecting moisture remaining inside the casing is provided in the sealed casing.
The base station according to claim 1 or 2, wherein when the water sensor detects water, a control circuit that monitors a detection signal of the water sensor notifies the base station management device to that effect.   A pressure sensor that detects the pressure inside the casing is provided in the sealed casing, and the control circuit that monitors the detection signal of the pressure sensor is used when the pressure in the casing is increased to a specified value or more, and after the pressure increase. The base station according to claim 3, wherein when the pressure is reduced to a specified value or less, the base station management apparatus is notified of the fact.   When the water sensor detects water and the pressure sensor continuously detects a pressure higher than a specified value and detects a predetermined time or more, the control circuit for monitoring detection signals of the water sensor and the pressure sensor The base station according to claim 4, wherein power supply from each power source to each electric circuit is stopped.

Images