JP2002051397A - Explosion-proof ultrasonic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an explosion-proof ultrasonic sensor, which is used for an anemometer, range finder, etc., at a location in danger of explosion by utilizing an ultrasonic transmitter/receiver, which radiates ultrasonic waves into the air or receives ultrasonic wave motions. SOLUTION: A cylindrical body 1 of this ultrasonic sensor which is to become an explosion-proof case is constituted by coupling a front cylindrical body 2 with a rear cylindrical body 3. At the front end of the front cylindrical body 2, an opened shell 20, and a sensor housing chamber 21 having a larger diameter than the shell section 20 has at are formed. The transmitter/receiver 4, which is incorporated in the body 1, is obtained by sticking a piezoelectric ceramic 42 to a casing 40. The transmitter/receiver 4 is housed in the sensor housing chamber 21, with its vibrating section 41 being directed toward the opened barrel section 20, and the spaces formed on both sides and the rear side of the inserted transmitter/receiver 4 are filled up with a silicone resin 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof ultrasonic sensor, and more particularly to an ultrasonic sensor having an ultrasonic transceiver.

[0002]

2. Description of the Related Art An ultrasonic sensor is provided with an ultrasonic transmitter / receiver, and is used in a wide range of fields such as radiating ultrasonic waves into the air or receiving ultrasonic waves to determine the presence of an object and measure the distance to the object. ing. Ultrasonic sensors are being used in a place where there is a danger of explosion in recent years. Needless to say, when using electrical equipment in an explosion-hazardous area, it must have an explosion-proof structure, but the ultrasonic transceiver itself vibrates, so if it is fixed in an explosion-proof case, the original function will be Explosion-proof construction was unsuitable because it would be lost.

[0003]

SUMMARY OF THE INVENTION The present invention utilizes an ultrasonic transmitter / receiver that emits ultrasonic waves into the air or receives ultrasonic waves.
Rangefinder, liquid level meter, contact prevention sensor for moving objects,
An object of the present invention is to provide an explosion-proof ultrasonic sensor that can be used as an intrusion alarm device or the like.

[0004]

Means for Solving the Problem A means for solving the problem is that a cylindrical main body serving as an explosion-proof case has a front cylinder and a rear cylinder connected to an explosion-proof structure, and a transmitter / receiver serving as a sensor is formed in a casing. A piezoelectric ceramic is fixed to the inner surface of the vibrating portion, and an opening body and a sensor housing chamber having a larger diameter than the opening body are formed in the front cylinder, and the transceiver is connected to the front part. This is characterized by being housed in a cylindrical sensor housing chamber and filling the side and rear portions of the transceiver with resin. In the above configuration, the tubular main body is formed by screwing a front tubular body and a rear tubular body together, and the transceiver is housed in a sensor housing chamber via an O-ring. Further, in the above configuration, the resin to which the transceiver is fixed is a silicon resin.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an assembled cross section, FIG. 2 shows a transceiver, and FIG. 3 shows an example of using an ultrasonic sensor.

In FIGS. 1 and 2, reference numeral 1 denotes a cylindrical main body serving as an explosion-proof case. A front cylindrical body 2 and a rear cylindrical body 3 are formed into an explosion-proof structure by screw connection, and a transceiver 4 is incorporated therein. Things. The front cylindrical body 2 has an opening body 20 at the front end, a sensor housing chamber 21 having a larger diameter than the opening body 20 at the rear end, and a first female screw 22 continuous with the sensor housing chamber 21. The opening body 20 and the sensor housing 21
Is formed in the engaging step portion 23. The rear cylinder 3 has the same outer diameter as the front cylinder 2 and has a male screw 31 connected to the female screw 22 of the front cylinder 2 on the front outer surface.
And a second female screw 32 is formed on the rear inner surface. In the embodiment, the front cylinder 2 and the rear cylinder 3 are screw-coupled, but other coupling structures may be used as long as they are explosion-proof structures.

The transmitter / receiver 4 is a sensor that uses a piezoelectric ceramic as a vibrator, generates an ultrasonic wave, radiates the ultrasonic wave into the air, or detects an ultrasonic wave from the air.
It is used in a wide range of fields, such as determining the presence of an object and measuring the distance to the object. The casing 40 is made of metal, preferably aluminum, and has a piezoelectric ceramic 42 attached to the inner surface of a vibrating portion 41 serving as a bottom. Two terminals 43 and 44 are provided, and one terminal 43 is a lead. Line 4
5, and the other terminal 44 is connected to the casing 40. In the figure, 46 is a coaxial cable connected to the terminals 43 and 44, 47 is a ground wire connected to the tubular main body 1, all of which are drawn out of the tubular main body 1.

When a signal voltage is applied between the two terminals 43 and 44, the piezoelectric ceramic 42
1 causes mechanical deformation corresponding to this voltage to cause bending vibration, and emits ultrasonic waves into the air. Also, when ultrasonic waves from the air are applied to the vibrating section 41,
Generates bending vibration with the piezoelectric ceramic 42, and the terminal 4
An electric output corresponding to the wave is generated between the 3, 44 electrodes. As a result, the former is used as a transmitter and the latter is used as a receiver.

In the embodiment, the transceiver 4 is a "Nicera aerial ultrasonic sensor" manufactured by Nippon Ceramic Co., Ltd.
You are using

In order to incorporate the transceiver 4 into the tubular main body 1,
First, the O-ring 5 is attached to the engagement step 23 of the front cylinder 2, and then the transceiver 4 is inserted from the rear of the front cylinder 2 with the vibrating section 41 facing the opening body 20, and The inclined shoulder 40a of 40 is brought into contact with the O-ring 5 already mounted. At this time, a gap is formed between the sensor housing chamber 21 formed in front of the female screw 22 of the front cylindrical body 2 and the side of the transceiver 4 housed therein. In addition, sensor accommodation room 2
1 is a cushioning material for preventing the vibration of the transmitter / receiver 4 from being transmitted to the tubular main body 1 in a gap between the transmitter / receiver 4 and an elastic resin for withstanding the internal explosion pressure and preventing escape of the flame. Specifically, silicon resin 6 is filled. In addition,
The O-ring 5 can be omitted as long as the resin filling the sensor chamber 21 does not flow out.

Next, the male screw 31 of the rear cylinder 3 is screwed to the female screw 22 of the front cylinder 2, and the cylindrical main body 1 is constituted by both cylinders. An earth ring 7 is mounted between the tip of the rear cylindrical body 3 and the silicone resin 6.
And the ground wire 47 are connected. The rear cylinder 3 is also filled with an elastic silicone resin 8 in the same manner as described above to support the rear part of the transmitter / receiver 4 and fix the coaxial cables 46 and the ground wires 47 of the terminals 43 and 44. are doing.

As described above, when an explosion accident occurs in the cylindrical main body 1, the flame is prevented from escaping toward the opening body 20 of the front cylindrical body 2 by the silicone resin 6, and the flame is prevented. Escape toward the joint between the two is prevented by the screw connection between the rear cylinder 2 and the rear cylinder 3, so that the cylindrical main body 1 has a complete explosion-proof structure.

In the present invention, only the cylindrical main body 1 has an explosion-proof structure, and a member connected to the rear cylindrical body 3 constituting the cylindrical main body 1 is connected to an appropriate housing depending on the use of the ultrasonic sensor. I can do it.

In the embodiment, a plug 10 is provided behind the rear cylinder 3. The plug 10 is provided with the second female screw 3 of the rear cylinder 3.
Adapter 2 connected to 2 through washer 11
And a sleeve 13 fitted outside the adapter 12
And a cone member 14 connected to the sleeve 13 to close the sleeve 13. The adapter 12 and the sleeve 13 are connected by screws 15. or,
A stay pipe 16 is fixed to the sleeve 13.
The coaxial cable 46 and the ground wire 47 are accommodated in the stay pipe 16.

FIG. 3 shows a case where the present apparatus is used as an anemometer. The ultrasonic sensors are used as a pair, and the vibration units 41 of the transmitter / receiver 4 are installed so as to face each other. The stay pipe 16 is a block 1 provided at the upper end of the stand pipe 17.
8, and a flange 19 is provided at the lower end of the stand pipe 17. As shown in the figure, two sensors are installed to face each other and the transmission / reception function is alternately switched, so that the sensor can be used as an intruder alarm device or the like in addition to the anemometer. When the sensor is used alone, it can be used as a liquid level meter or a distance meter by measuring the pulse reflection time.

In the embodiment, the cylindrical main body 1 has an outer diameter of 30 m.
m, the length is 52 mm, and the threaded joint between the front cylinder 2 and the rear cylinder 3 is 10 mm in length. The opening body 2 of the front cylinder 2
0 is an inner diameter of 17 mm, sensor chamber 21 is an inner diameter of 23 mm,
The vibration part 41 of the transceiver 4 has a diameter of 10.8 mm. In FIG. 3, the stand pipe 17 and the stay pipe 16
Is arbitrary, but the mounting interval of the transducers of the transceiver (4) facing each other is 300 to 400 mm.

[0017]

According to the present invention, an ultrasonic transmitter / receiver for radiating ultrasonic waves into the air or receiving ultrasonic waves is housed in an explosion-proof structure.
This has the effect of being simple. Also, the cylindrical body is
Since the front cylinder and the rear cylinder are screwed together, even if an explosion occurs in the cylinder, the screw prevents the flame from escaping. Further, the transceiver is located between the sensor housing and the sensor housing.
Since the ring is attached, the resin to be filled is prevented from flowing out.

[Brief description of the drawings]

FIG. 1 is an overall sectional view showing an ultrasonic sensor of the present invention.

FIG. 2 is a cross-sectional view of a transceiver.

FIG. 3 is a front view showing a usage example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical main body 2 Front cylinder 3 Rear cylinder 4 Transceiver 5 O-ring 6 Silicon resin 7 Earth ring 8 Silicon resin 10 Plug 11 Washer 12 Adapter 13 Sleeve 14 Cone member 15 Screw 16 Stay pipe 17 Stand pipe 18 Block DESCRIPTION OF SYMBOLS 19 Flange 20 Opening trunk 21 Sensor accommodation room 22 First female screw 23 Engagement step 31 Male screw 32 Second female screw 40 Casing 40a Inclined shoulder 41 Vibration part 42 Piezoelectric ceramic 43 Terminal 44 Terminal 45 Lead wire 46 Coaxial cable 47 ground wire

Continuation of the front page (72) Inventor Makoto Yamazaki 1-9-9 Kakimotocho, Toyota City, Aichi Prefecture Inside Trinity Industry Co., Ltd. (72) Inventor Hidetoshi Omori 1-9-9 Kakimotocho Town, Toyota City, Aichi Prefecture Trinity Industry Co., Ltd. F term (reference) 5D019 AA18 BB12 EE01 FF01

Claims (4)

[Claims] An explosion-proof case has a cylindrical main body (1) in which a front cylinder (2) and a rear cylinder (3) are connected to an explosion-proof structure, and a transmitter / receiver (4) serving as a sensor is provided. A piezoelectric ceramic (42) is fixed to an inner surface of a vibrating part (41) formed in a casing (40). The front cylindrical body (2) has an opening body (20) and the opening body. A sensor housing (21) having a diameter larger than that of (20) is formed, and the transceiver (4) is housed in the sensor housing (21) of the front cylinder (2), and the transceiver (4) is formed. An explosion-proof ultrasonic sensor characterized in that a resin (6, 8) is filled in side and rear portions of the ultrasonic sensor. 2. The explosion-proof type according to claim 1, wherein the cylindrical body (1) is formed by connecting a front cylindrical body (2) and a rear cylindrical body (3) with screws. Ultrasonic sensor. The transceiver (4) is provided in the sensor housing (2).
2. The explosion-proof ultrasonic sensor according to claim 1, wherein the ultrasonic sensor is housed in 1) via an O-ring. 4. The explosion-proof ultrasonic sensor according to claim 1, wherein the resin fixing the transceiver (4) is a silicone resin.