JPH0574010B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides gas
It is used as a vibration sensor that emits a predetermined ON-OFF signal as a vibration sensor that controls oil and other fuel shutoff valves, and is particularly designed to distinguish between vibrations caused by earthquakes and other noise-like disturbance vibrations. This invention relates to a seismic sensor that outputs electrical signals with different ON-OFF ratios.

[Background technology]

Previously, a patent application for this type of seismic sensor was filed in 1986.
There is something like the one disclosed in No. 14745,
In particular, the normally OFF type seismic sensor body, that is, the pot 1 and the cover plate 2 shown in FIG. 1 of the drawings attached to this specification.
Mercury grains 3 are enclosed in a sealed container configured with the following, and are fixed to the lid plate 2 in an airtight and electrically insulated manner, and the electrode 4A in the sealed container of the lead pin 4 is a circular body made of a thin nickel alloy wire. If the pot 1 and the bottom surface of the cover plate 2 are arranged at a certain distance so as not to come into contact with each other, a lateral vibration acceleration with a waveform similar to an earthquake wave is applied to the seismic sensor. The ON-OFF signal emitted from the seismic sensor is different from the ON-OFF signal emitted from the seismic sensor when a lateral vibration acceleration with a waveform different from that of the seismic wave, which is disturbance noise, is applied. It has the disadvantage that it is difficult to clearly distinguish the desired ON-OFF pattern as a signal.

[Summary of the invention]

In order to eliminate the above-mentioned drawbacks, the seismic sensor of the present invention has the following features:
The mercury grains respond well to the lateral vibration of the waveform that simulates seismic waves, turning them on and off as desired.
The mercury particles are always placed in a fixed position when the pot, which is a container for receiving the mercury particles, is stationary so as to generate a signal, and to generate different ON-OFF signals in response to horizontal vibrations of different periods which are disturbances. An electrode body having a radial blade-like shape with almost no resistance in the radial direction that moves in response to transverse vibration from a location is provided, and the ON time during movement during which mercury particles are sandwiched between the blade electrodes and comes out from between them is determined. When the mercury grains receive even a small amount of force with a component perpendicular to the vibration direction by adjusting the ratio between the OFF time and the OFF time, the mercury grains rotate in synchronization with the period of the lateral vibrations, resulting in regular reciprocation. In order to prevent the motor from moving and therefore producing irregular ON-OFF signals that are completely undesirable,
Rotational movement is prevented by rectifier plates provided radially on the blade electrodes or pots.

[Embodiments of the invention]

As shown in FIGS. 1 and 2, a pot 1 made of an iron plate by a method such as drawing has a recess 1A in the center in which a mercury grain 5 is normally placed, and a slope adjacent to the recess 1A. It is composed of a limp bottom surface 1B, a substantially vertical wall surface 1C, and an open end portion 1D. The lid plate 2 has a donut-like shape with a hole 2A in the center of a relatively thick iron plate.
A conductive pin 4 made of, for example, an iron-nickel alloy is hermetically sealed with an electrically insulating filler 3 such as glass. An electrode 4A having radial wing portions 4B ₁ to 4B ₈ shown clearly in FIG. 2 is fixed to the conductive pin 4 by a method such as spot welding. The entire inner surface of the pot 1 is roughened so that the mercury particles 5 can easily roll around. Therefore, the contact between the mercury particles 5 and the pot 1 is electrically unstable and the resistance value fluctuates. Near the outside of the bottom of pot 1, a ring-shaped contact 1E for stabilizing electrical resistance is made of iron or, more preferably, an iron-nickel alloy, and is fixed to the inner surface of pot 1 by a method such as spot welding. . After storing a predetermined amount of mercury particles 5 in a pot having such a structure, the lid plate 2 and the open end 1 of the pot 1 are opened in a predetermined non-oxidizing atmosphere.
D are hermetically fixed by a method such as ring projection welding. It should be noted that the electrode 4A has 4C _{1 to 4C} as shown particularly clearly in FIG.
A hole named 4C ₄ is drilled, and this is because when mercury particles are scattered when subjected to strong vibrations, the mercury particles will ride on top of the electrode and be sandwiched between it and the cover plate 2 in the normal position. This is to prevent it from not returning to its normal position under such conditions. A good way to place the seismic sensor shown in Figure 1 in its normal position without tilting it is to fix it in a suitable case made of synthetic resin, for example, but in order to place it in its normal position even more accurately, A method such as that disclosed in Patent Application No. 14745 of 1988 is preferred.

When a vibration sensor placed in a normal position is placed on a vibration table and a horizontal vibration is applied as shown by arrow A in Figure 1, the mercury particles will move to the normal constant as shown by the solid line. It vibrates left and right from the position, and when the vibration acceleration reaches a predetermined threshold value, for example, 140 gal, it flows out of the recess 1A of the pot 1 and moves outward as shown by the dotted line, and then moves left and right in response to the vibration period. Therefore, the contact 1E fixed near the outer periphery of the bottom of the pot and the electrode 4A fixed to the conductive pin 4 are electrically short-circuited by the mercury grains 5, and a short circuit is created between the pot 1 and the conductive pin 4. When current passes through it, an ON-OFF signal is generated.

For example, 0.3 seconds to 0.7 seconds is usually used as a representative value for the period of an earthquake. Therefore, as a seismic sensor, there is an ON-OFF signal that is generated when vibrating with an acceleration above the threshold value in a cycle of 0.3 seconds to 0.7 seconds, and an ON-OFF signal that is generated when vibrating with an acceleration above the threshold value in other cycles. If the ON and OFF signals are different, it can be easily distinguished by a computer incorporating a comparison circuit.

As a specific experimental example, we used a mercury particle of about 0.3 grams (the lateral diameter of this weight is about 3.6 mm), and the inner diameter of the electrode, that is, D ₁ shown in Figure 2, was
5.5 mm, the outer diameter _D2 of the electrode is 8 mm, and the inner diameter _D3 of pot 1 is 9.5 mm.As shown in the graph shown in Figure 4, the horizontal axis shows time, and the ON-OFF The convex-concave line L indicates that when the period is 0.7 seconds, the ON-OFF time is the acceleration threshold, for example, at 140 gal, ON is 0.06 seconds,
OFF time was 0.29 seconds. We also set the acceleration to a threshold of 2.2
When set to 300 gal, which is slightly less than double, ON is 0.11 seconds and OFF is 0.24 seconds.
It changed in about seconds. If the period is 0.5 seconds, the uneven line M
As shown in , the threshold value is 0.06 seconds when ON and 0.19 seconds when OFF.
At 300 gal, ON was 0.09 seconds and OFF was 0.16 seconds. Also, when applying vibration with a period of 0.3 seconds, the threshold acceleration is ON for 0.055 seconds, as shown by the uneven line M.
OFF is 0.095 seconds and ON is 0.065 at an acceleration of 300 gal.
seconds, OFF time was 0.085 seconds. The period of noise vibration, that is, disturbance, is 0.15, for example, in the case of vibrations caused by heavy vehicles passing over uneven roads, or by pile driving at road construction or construction sites.
For example, when the vibration acceleration is 140 gal, the ON time is 0.02 seconds or less.
Even when a large vibration of 550 gal was applied, the ON time was 0.04 seconds and the OFF time was 0.11 seconds or more, as shown by the uneven line P. Therefore, it is clear that vibrations with a period of 0.3 to 0.7 seconds, which are common in seismic waveforms, and disturbance vibrations are determined by ON time as a discrimination criterion for microcomputers.
If a pattern of 0.05 seconds or more and OFF time of 0.06 seconds or more occurs five or more times in a three-second period, it will be determined as an earthquake and a command will be issued to shut off safety devices, such as gas shutoff valves. I can do things.

Furthermore, in the event of a major earthquake, a device to which a seismic sensor is attached may topple over, so in this case, the seismic sensor will continue to be in the ON state. Therefore, the microcomputer mentioned above is programmed to issue a command to stop the shutoff valve if the ON state continues for more than 1 second. When a ball is accidentally hit by a tossing ball, the seismic sensor is subjected to an instantaneous vibration acceleration of over 1000 gal, although the period is short, which may decay after a few seconds and come to rest. Since there is a possibility that rotational movement of the mercury grains 5 may occur only with the structure of the electrode in the embodiment shown in FIGS. , an electrical insulator is applied only to the inner diameter end surfaces of the blade portions 4B ₁ to 4B ₈ of the electrode 4A shown in FIGS. 1 and 2 so that an ON signal will not be generated even if the mercury particles 5 come in contact with these parts. It turned out to be a good thing. Among the eight blade portions of the electrode 4A, the inner diameter end surfaces to which the electrical insulator is applied are indicated by diagonal lines for the blade portions 4B ₂ , 4B ₃ and 4B ₄ in FIG.

As another embodiment, as shown in FIG. 3, thin rectifying plates 6A and 6B are provided radially on the bottom of the pot so that there is almost no rolling resistance of the mercury particles 5 in the radial direction.
6H are provided in a shape that provides resistance in the direction of rotation of the mercury grains 5, and a ring-shaped hole is provided near the outer periphery of the bottom surface of the pot 1 in the aforementioned embodiment shown in FIG. 1 to stabilize the electrical resistance. contact 1
It may be used instead of E. When the current plates 6A to 6H are provided in pot 1, the first
The electrode 4A shown in the figure may be a simple ring-shaped electrode without the blade portions 4B ₁ to 4B ₈ .

〔Effect of the invention〕

As mentioned above, in the case where the electrode 4A is a conventional simple ring without a radial blade part, or in the case of a seismic sensor without a rectifying plate on the bottom of the pot 1, the period is, for example, 0.1 to 0.14 seconds. At first, the mercury grains are reciprocating between the mercury grains, but this is thought to be caused by a force perpendicular to the vibration direction acting on the mercury grains due to some kind of tightness. As shown by the uneven line Q, the ON state may continue, and if the electrode is a simple ring, the orbit may deviate slightly during the reciprocating motion of the mercury drop if the period is relatively long, such as 0.7 seconds. Especially when the gal value is not relatively large near the threshold, two ON cycles occur during one reciprocating movement, as shown by the uneven line R.
- Since the OFF operation does not occur and it becomes like a blank, the above-mentioned microcomputer's discrimination criterion is that ON-OFF does not appear more than 5 times within 3 seconds and it is not considered that an earthquake has been felt. It has excellent industrial effects without causing any problems.

[Brief explanation of the drawing]

FIG. 1 shows a longitudinal sectional view of a seismic sensor according to an embodiment of the present invention, and FIG. 2 shows a plan view taken in the direction of the - line arrow in FIG. FIG. 3 is a perspective view showing a partial view of a vibration sensor according to another embodiment. FIG. 4 is a graph showing the ON-OFF output waveform of the seismic sensor. DESCRIPTION OF SYMBOLS 1...Pot, 1A...Central recess, 1B...Sloped bottom surface, 1C...Wall surface, 1D...Open end, 2...Lid plate, 3...Electric insulation filler, 4...
Conductive pin, 4A...radial electrode, 5...mercury grain,
6A to 6H... Rectifier plate.

Claims (1)

[Claims] 1 A predetermined amount of mercury is placed in a sealed container constructed by joining a pot with a central concave part, a sloped bottom surface, and a concentric wall surface, and a lid plate to which a conductive pin is electrically insulated and fixed to the open end of the pot. It is made by enclosing grains,
A radial electrode having a shape such that rolling resistance is relatively low in the radial direction of the mercury grains and large in the circumferential direction is provided on the inside of the sealed container of the conductive pin, or a radial electrode is provided on the bottom surface of the pot. By providing a radiation baffle plate near the outer periphery of the mercury grains with a shape such that the rolling resistance is relatively low in the radial direction and the rolling resistance is large in the circumferential direction, the desired ON- A seismic sensor characterized by generating an OFF signal.