JPS582685A - Vibration source for seismic prospecting - Google Patents

Abstract

PURPOSE:To achieve a miniaturization and a higher efficiency by driving a piston to produce an impact based on difference in the pressure working on both sides thereof depending on reduction in the volume following the combustion of mixed gas of hydrogen and oxygen introduced into a cylinder. CONSTITUTION:This apparatus is equipped with a cylinder 1, a piston 2 incorporated thereinto, a mixed gas supply section 4 which supplies hydrogen and oxygen at a volume ratio of about 2:1 both to cylinder chambers 3a and 3b partitioned by the piston 2, ignition plugs 5a and 5b and a high voltage generating circuit 6 for ignition of the ignition plugs. When a mixed gas is ignited with the ignition 5a, internal pressure of the cylinder chamber 3a drops so sharply that the piston 2 falls by its own gravity and a differential pressure of a cylinder space to impact the bottom of the cylinder 1. This achieves a miniaturization and a high efficiency of the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a seismic source device for seismic exploration, and more specifically, the present invention relates to a seismic source device for seismic exploration, and more specifically, it uses an instantaneous decompression effect based on a chemical reaction of a hydrogen/oxygen mixed gas to forcibly drive a movable member by a pressure difference. The present invention relates to a seismic source device configured as described above.

As is well known, seismic exploration shows that earthquake waves travel faster in hard rocks and slower in softer rocks.
By making use of reflection and refraction at the interface between strata and artificially creating vibrations at one point on the ground or underground, and measuring the arrival time of the resulting elastic waves at different points at various distances from the epicenter. This is to estimate the underground structure.

There are various methods of seismic source devices for seismic exploration, but typical ones include blowing up gunpowder, hoisting up a weight with a winch, and using the impact of the free fall of the weight. There is. However, the former has drawbacks such as the large scale of implementation, high risk, and the inability to implement it repeatedly. Conversely, the latter can be carried out repeatedly and relatively easily, but since the energy given to the ground by the free fall of a weight is approximately proportional to the height of the hoisted weight from the ground, it is necessary to increase the impact energy. However, the equipment needed to be large, making it extremely difficult to transport the roots to places where there are no roads, such as mountain tops, and it was impossible to use them as sources inside polling holes. Furthermore, it was theoretically impossible to apply a horizontal impact to the ground.

The purpose of the present invention is to eliminate the drawbacks of the prior art as described above, and to provide a system that is compact, highly efficient, and highly safe, and that is
The objective is to provide a new type of source that can be used for both wave and seismic exploration.

In order to achieve this objective, the present invention burns a mixed gas of hydrogen and oxygen introduced into the cylinder, takes advantage of the subsequent volume reduction, and drives the piston mainly by the difference in pressure applied to both sides of the piston to generate an impact. This is precisely the feature of the present invention.

The present invention will be explained in more detail below.

The drawing is a principle explanatory diagram showing a -j embodiment of the present invention. As is clear from Figure 1, this device supplies hydrogen and oxygen at a ratio of approximately 2:1 to both the cylinder 1, the piston 2 incorporated therein, and the cylinder chambers 3a and 3b partitioned by the piston 2. Mixed gas supply section 4 that supplies by volume ratio
and spark plugs 5 installed in both chambers 7 and 7 respectively.
m, 5b, and a high voltage generating circuit 6 for igniting the spark plugs 5a, 5b. The piston 2 has an OIJ ring 7 on its central outer periphery, whereby the cylinder 1
It is able to slide airtightly and axially inside the body, and both end faces are bulged in the axial direction, resembling a hammer head. Mixed gas supply section 4
is equipped with a hydrogen gas cylinder 10, an oxygen gas cylinder 11, and a flow rate adjustment device 12 that mixes the gases from them at a volume ratio of approximately 2 hydrogen:10 oxygen, and the mixed gas is controlled by on-off valves 13a, 13b, check valves 14a, It can be supplied to the cylinder chambers 3a, 3b through a flow path having 14b.

Incidentally, the spark plugs 5a and 5b can be the same as those used as spark plugs in automobiles and the like. A switch 15 inserted between each spark plug 5a, 5b and the high voltage generation circuit 6 is a changeover switch for selecting a spark plug.

The device operates as follows. First, when applying a vertical impact to the ground 20, the present device is erected on the ground 2o as shown in Figure 1. Lower on-off valve 1
3a is opened, a mixed gas adjusted to hydrogen and oxygen is sent into the lower chamber 7/d chamber a, and the piston 2 is pushed upward. When the mixed gas is ignited with the spark plug 5a in this state, the gas instantly explodes and burns, changing into water. Since the temperature of this device is about the same as the ambient temperature, and the heat capacity of the cylinder 1 and piston 2 is also quite large, most of the mixed gas turns into water droplets. Therefore, the spark plug 5a
As a result of the ignition, the internal pressure in the cylinder chamber 3a decreases rapidly, and as a result, the piston 2, which had been pressed against the other cylinder, falls due to its own weight and the differential pressure between the two cylinder chambers, giving an impact to the bottom of the cylinder 1. That force is transmitted to the ground 20.

In the above operation explanation, when the mixed gas is supplied to the lower cylinder chamber 3a, the gas in the upper cylinder chamber 3b is compressed by the pressure, which creates a differential pressure at the time of ignition. Although this is preferable because it allows a larger impact force to be applied, depending on the case, the upper cylinder chamber 3b may be communicated with the atmosphere.

In addition, if the piston 2 is held in the upper part of the cylinder 1 by mechanical locking means and the locking release operation and the plug ignition operation are performed in synchronization, the piston 2 is heavy and the lower cylinder Even if the pressure of the mixed gas supplied into the chamber 3a is low, sufficiently satisfactory operation can be achieved.

Next, if it is desired to apply an impact to the ground 20 in the horizontal direction, this device may be installed horizontally as shown in Figure 2. for example,
The ground 20 is leveled, a stand 21 is provided, and the device is placed and fixed on it to stabilize it. When a mixed gas is introduced into one cylinder chamber and ignited, the internal piston is driven in one direction by the pressure difference between both cylinder chambers, and can apply a horizontal impact to the ground. Moreover, if the mixed gas is introduced into the other cylinder chamber and ignited, the internal piston moves in the opposite direction, so that an opposite horizontal impact force can be applied to the ground.

Although not shown, the cylinder 1 is provided at both ends with a portion for storing generated water and a suitable drainage valve. In addition, in the case of a device that only applies impact in the vertical or horizontal direction, the cylinder chamber or spark plug.

It is sufficient to provide one check valve or the like.

Since the present invention is fundamentally configured to utilize pressure difference as force as described above, it can be mechanically simplified;
Therefore, it is small and lightweight and can generate a large impact force, and can be used both vertically and horizontally, so the single-S device can be used for both P-wave and S-wave seismic exploration. There is no need to send a very high pressure gas into the cylinder, and since the volume reduction after combustion is used, there is little danger, and it is easy to repeatedly generate vibrations. It has many excellent effects, such as no noise vibrations, a high S/N ratio, and easy transportation.

[Brief explanation of the drawing]

Figure 1 of the spear is an explanatory diagram showing an embodiment of the present invention, and Figure 2 of the fang is an explanatory diagram showing an example of its usage state. 1...Cylinder, 2...Piston, 3a, 3b...
・Cylinder chamber, 4...Mixed gas supply section, 5a, 5b・
...Spark plug. Patent applicant: Yukio Omata, agent of Applied Geological Survey Co., Ltd.

Claims (1)

[Claims] 1. A mixture in which hydrogen and oxygen are supplied at a volume ratio of approximately 2:1 to a cylinder, a piston that is airtightly and slidably incorporated into the cylinder, and at least one of the cylinder chambers partitioned by the piston. It is equipped with a gas supply section, a spark plug installed in the cylinder chamber to which the mixed gas is supplied, and a high voltage generation circuit for igniting the spark plug, and utilizes the pressure difference between the two cylinder spaces partitioned by the piston. A seismic source for seismic exploration that drives a piston to create an impact.