JPH0674998B2 - Seismic device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention detects vibrations such as an earthquake and outputs an ON-OFF signal to operate a shutoff valve of a fluid fuel such as city gas / propane gas or oil. The present invention relates to a seismic sensor used as a safety device.

[Conventional technology]

Examples of this kind of seismic sensor include, for example, Japanese Patent Application No. 238399 in 1987.
Nos. 1988, Patent Applications No. 168831 and No. 302012, and the like as described in the specification and drawings are proposed.

[Problems to be solved by the invention]

However, when a conductive liquid such as mercury is used as the inertial element, a predetermined ON-OFF signal is generated for a sinusoidal acceleration with a period of 0.3 to 0.7 seconds that is used as a horizontal vibration acceleration due to an earthquake. When a disturbance vibration exceeding the above-mentioned range is applied as a gull value at a short vibration acceleration of 0.2 seconds or less, the disturbance vibration is initially a large gull value. Since it exceeds the area of, the ON-OFF output signal synchronized with the cycle is output, but this is the ON-OFF output signal at the cycle of 0.3 seconds to 0.7 seconds which substitutes the above-mentioned earthquake and the ON time and OFF
Since the absolute value of the time length is different, it is possible to clearly distinguish the earthquake and the disturbance vibration by the microcomputer, but in the process of damping, the conductive liquid continues the detour motion other than simple vibration for a long time. In some cases, this causes the microcomputer to make an erroneous determination as if the operating state.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a reciprocating motion caused by the above-mentioned disturbance vibration by making the shape of the inner bottom surface of the closed container serving as a tray for the conductive liquid as the inertial member spherical and providing the electrodes radially. When the gull value is smaller than the response area in the process of decaying, the trajectory is similar to the pendulum damping and stopping without detouring. It is configured so that it is attenuated by the vibration of the, and the signal of the period which is the substitute characteristic of the earthquake and the signal which is generated in the period of the disturbance vibration can be clearly distinguished by the microcomputer.

[Work]

According to the present invention, as described above, the shape of the bottom surface of the container, which is a tray for the conductive liquid, is a part of a sphere, and the radial electrode is provided to be electrically insulated from the center of the container in a radial direction outward. In an ordinary stationary posture, the inertial liquid, which is the conductive liquid, is located in the center of the container in a shape that is close to a sphere, but has a shape in which the vertical direction is slightly smaller than the left and right diameters, and is separated from the radial electrode. ing. When horizontal vibration is applied, it rolls on the pan like a pendulum in that direction, and the amplitude increases or decreases according to the acceleration value, and when it exceeds the response threshold, it contacts the electrode and outputs an ON-OFF signal. However, since the shape of the electrodes and the like is radial, even if the electrodes come into contact with each other, the detouring motion in a direction other than the vibration direction is prevented. Therefore, since an ON-OFF signal that almost matches the cycle is generated, it is possible to clearly distinguish between disturbance vibration and earthquake by predetermining the ON time and OFF time by the microcomputer.

〔Example〕

As shown in FIG. 1, a container 1 which is a saucer made by a method such as drawing an iron plate has a conductive liquid 5 such as mercury at the bottom thereof which is placed at the center of the spherical surface when the container is stationary, and has a spherical shape. It is composed of a bottom surface 1A, a substantially vertical wall surface 1B, and an opening end portion 1C. The cover plate 2 has a hole in the center of a relatively thick iron plate.
The hole 2A has a donut shape, and a conductive pin 4 made of, for example, an iron / nickel alloy is hermetically sealed and fixed in the hole 2A by an electrically insulating filler 3 such as glass / ceramic. The lid plate 2 and the container 1 are bonded together at their joint surfaces by a method such as ring projection welding to form a closed container. This is a non-oxidizing atmosphere such as helium or an inert gas such as argon or hydrogen. It is performed in an atmosphere of a reducing gas such as gas or a mixed gas of two or more kinds of these gases. An electrode 6 having a radial blade-shaped contact piece as shown in the figure, which is made of a material such as iron or an alloy of iron and nickel, is fixed to the lower end portion 4A of the conductive pin 4 protruding into the closed container. The electrode 6 is 8 around the central portion 6T as shown in the plan view of FIG.
The contact pieces 6A to 6H are formed by bending the contact pieces at right angles to the central portion 6T of a thin metal plate, for example, so as to have a small area when viewed from a plane. The number of contact pieces is not necessarily limited to eight in relation to the diameter of the envelope connecting the inside of the contact pieces with the amount of the conductive liquid 5, and a minimum of three is possible. That is, the contact pieces 6A to 6H of this electrode
The role of is that if the contact piece is assumed to be circular rather than radial as shown in this figure, the conductive liquid 5 will rotate along the inside of the container in response to horizontal vibration, This is to prevent the phenomenon that the ON-OFF signal of is not emitted, and makes a detour so that an ON-OFF electric signal is obtained by making a motion like a pendulum that is always synchronized with the vibration of each cycle that exceeds the response area gal value. The shape of the electrode for preventing movement is not limited to this embodiment. Further, in this embodiment, normally when the conductive liquid 5 is stopped at the center of the bottom surface of the container 1, it is turned off.
In other words, it is a normally open type contact type, but depending on the purpose of use, it is a normally closed type seismic sensor, for example, Japanese Patent Publication No. 22/1984.
It can also be applied to an electrode in which a slender central electrode is constantly in contact with a conductive liquid in a static state as shown in No. 8123.

Due to the relationship between the width between the contact pieces of the electrodes 6 housed inside the container 1, the size of the conductive liquid 5 and the size of the radius of the sphere on the bottom of the container, the conductive liquid 5 as an inertia rolls and rolls out. The threshold that responds to the horizontal acceleration required to move toward is determined, but when an acceleration above this response threshold is applied, the conductive liquid 5 causes the contact pieces 6A to 6H of the electrode 6 to contact.
And the container 1 are electrically short-circuited. That is, the conductive pin 4
When a vibration acceleration such as an earthquake is applied between the lid plate 2 and the container constituting the closed container and the container, an ON-OFF output signal is obtained. The seismic waveform has a wide range of periods, but a sinusoidal waveform with a period of 0.3 to 0.7 seconds is usually applied as a substitute characteristic. Assuming that the area of the response threshold of the seismoscope of this example is 100 gal to 150 gal, the output of the seismoscope is set by setting the period to 0.7 seconds, 0.5 seconds, and 0.3 seconds with a sine waveform above this reaction area. The signals are shown as curves A, B and C in Fig. 3, respectively.
Get ON-OFF signal. It should be noted that there is a characteristic that the one with a cycle of 0.5 seconds is smaller than the response threshold with a cycle of 0.7 seconds, and the reaction threshold with a cycle of 0.3 seconds is lower than that, and that the threshold of the cycle of 0.3 seconds is about 100 gal. There is a difference of about 135 gals for 0.5 seconds and a threshold of 0.7 seconds for a period of 0.7 seconds. On time of 40 ms or more and off time of 50 by microcomputer
When the condition is set such that if an ON-OFF signal such as a millisecond or more is within 3 seconds and there are 5 cycles or more within 5 seconds, it is determined that an earthquake has occurred, the ON-OFF signal represented by the curves A, B, and C Meets the condition, the microcomputer outputs a command to generate an earthquake and activates a safety device such as closing a shutoff valve for gas.

However, if the setting location of this seismic sensor is, for example, a city gas meter, this gas meter is usually installed outdoors, so that people passing by this area can inadvertently use the gas meter as a gas meter. It must be taken into consideration that a ball hitting the ball or hitting a gas meter accidentally hits the gas meter when the child is playing the ball. in this case,
Although there are some differences in the gas pipe support method due to differences in the distance between the support points of the fixtures, a vibration acceleration of approximately 1000 gals, which is a sinusoidal waveform, was generally observed in a cycle of about 0.1 seconds. When the motion threshold of the seismic sensitive device is set to 100 gal, the seismic sensitive device is naturally synchronized with the cycle of about 0.1 seconds.
N-OFF signal is output, but each ON time and OFF time is 20
Since it is from millisecond to 30 milliseconds, the microcomputer does not judge the earthquake. However, when the vibration acceleration attenuates and falls below the threshold value, the conductive liquid is a liquid with less mechanical friction loss due to inertia, so there is a recess in the center or a non-sphere like a conventional container. If it is a conical shape, it will cause a detouring motion other than in the radial direction on the pan and will be unstable.
Generates an ON-OFF signal. This is random as shown by the curve D in Fig. 3, but for the time being, it corresponds to a signal that the microcomputer's seismic judgment criterion is ON time 40 ms or more and OFF time 50 ms or more, and within 3 seconds. If 5 cycles occur, it will be very annoying because it will malfunction due to disturbances other than the earthquake.

Thus, according to the gist of the present invention, the shape of the bottom surface of the container 1 serving as a tray for the conductive liquid 5 is spherical and the contact 6A of the electrode 6 is provided.
By making 6H to 6H radial, it becomes possible to regulate the movement of the conductive liquid 5 in the same trajectory as the movement of the pendulum,
It is possible to prevent damage caused by the detouring movement of the conductive liquid 5 as an inertia element, which was extremely incomprehensible in the past, and the amplitude of the conductive liquid is simply reduced in the process of damping the disturbance vibration. Aside from the time, it was possible to prevent the generation of a signal whose ON time was longer than that required from the vibration cycle.

〔The invention's effect〕

As described above variously, the seismoscope of the present invention is provided with the contact portion of the conductive liquid container such as mercury having a spherical surface, and the radial and downward hook-shaped contact portion when the electrode is always OFF type. If it is always on, a thin electrode is provided in the center and the detouring motion of the inertial element at the time of damping the disturbance vibration is caused by the interaction effect with the radial wall surface at the same potential as the saucer near the inner circumference of the container. By establishing a reciprocating motion that matches the cycle, it is possible to obtain an inexpensive seismic sensor with a simple and clear structure that enables the microcomputer to reliably determine the distinction between earthquakes and other noise vibrations with an ON-OFF signal. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view according to an embodiment of the present invention, and FIG.
FIG. 3 is a plan view showing a part of the figure, and FIG. 3 is a characteristic diagram for explaining the output signal of the seismic sensor. 1 ... Container, 1A ... Bottom, 1B ... Wall, 1C ... Open end, 2 ... Lid plate, 3 ... Insulating filler, 4 ... Conductive pin, 5 ... Conductive liquid, 6 ... Electrode .

 ─────────────────────────────────────────────────── ─── Continuation of front page Examiner Naohide Murata (56) References JP-A-1-280223 (JP, A) JP-A-2-147825 (JP, A) JP-A-64-79624 (JP, A) Special Features Kosho 59-18334 (JP, B2)

Claims (1)

[Claims] 1. A container made of a conductor having a spherical bottom surface and a substantially vertical wall surface, and a closed container formed by joining a lid plate electrically insulating and fixing conductive pins to the open end of the container. A conductive liquid and an inert gas or the like that does not contaminate the same, and the lower end of the conductive pin in the closed container is electrically insulated from the container along the radial direction from the center. A seismoscope characterized in that it is provided with electrodes consisting of three or more contact pieces provided with hook-shaped contact portions radially and downward.