JPH0436432Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an underground gas sampling device.

(Conventional technology) Construction work is carried out in places where gas is generated from underground, such as on the site of a waste disposal site, or in places where there is a possibility of oxygen depletion due to strata containing a lot of iron. or if you plan to use it for a park, etc.
Depending on the condition of underground gas, there is a possibility of an explosion or an oxygen deficiency accident, and it may also have a negative effect on plants, making it necessary to collect underground gas.

For this reason, conventional methods include placing a strainer at the location where air is to be sampled using a borehole, closing the top of the borehole, and drawing air from that part with a tube, etc.; The method used was to attach a filter to the tank and collect air.

(Problems to be Solved by the Invention) However, in the conventional method, the time and cost required for the boring work are large, and gas dissipation and atmospheric air are mixed in during boring. Furthermore, in the latter method, when the tube is driven into the ground, the filter at the tip gets clogged, and air gets mixed in through the gap between the sampling tube and the soil.

(Means for solving the problem) The present invention was proposed to solve the above problem, and has a vertical hole for sampling air in the center.
A core tube having a slit that communicates with the vertical through hole at the outer periphery of the lower end and having a shoe fitting at the lower end, and a slit portion of the core tube that is slidably fitted to the outer periphery of the concentric tube and has a slit portion of the core tube at the lower end. an inner tube having a bulge that covers the
An annular flexible member is slidably fitted around the outer periphery of the inner tube, has a lower end curved toward the outer periphery, and has a lower edge resting on the upper step of the bulged portion of the inner tube. The present invention relates to an underground gas sampling device characterized by comprising an outer pipe provided with an air barrier.

(Function) Since the underground gas sampling device according to the present invention is configured as described above, it can be slidably moved sequentially into the concentric pipe and its outer circumference using the foot metal fitting attached to the lower end of the core pipe. After the fitted inner and outer pipes are press-fitted into the ground, when the inner pipe is pulled up, the slit at the lower end of the core pipe, which had been covered by the bulge provided at the lower end of the inner pipe, is removed. Once exposed, the underground gas enters the vertical hole in the core pipe through the slit, rises inside the hole, and is collected.

On the other hand, as the inner tube is pulled up, an annular flexible air barrier is clamped between the bulge at its lower end and the lower end of the outer tube. Since the barrier has been curved outward in advance, it curves further outward and is pressed against the soil around the outer periphery, blocking air from above.

(Effects of the invention) In this way, the invention makes it easy to remove underground gas.
In addition, the core pipe and both the inner and outer pipes are configured to be press-fitted into the ground, so it is possible to collect the sample without atmospheric air coming in from above. Compared to other methods, this method can save construction costs and shorten the construction period, and there is no risk of underground gas dissipating or air being mixed in during boring.

In addition, the slit at the lower end of the core tube provided for underground gas sampling is covered by the bulge provided at the lower end of the inner tube until it is press-fitted into a predetermined position in the ground, so there is no filter at the tip. The filter constituting the air sampling section does not become clogged unlike in the conventional method using a single pipe with an air sampling section.

(Example) The present invention will be described below with reference to the illustrated embodiments.

A is a core tube having a metal fitting 1 at its lower end, a vertical through hole 2 is bored in the center, and a slit portion 3 communicating with the vertical through hole 2 is provided on the outer periphery of the lower end.

Reference numeral B denotes an inner tube slidably fitted around the outer periphery of the core tube A, which is provided with a bulge 4 at its lower end, and has slits 5 extending vertically at predetermined positions on its outer circumferential surface. It is cut out.

Note that the outer circumferential surface of the bulging portion 4 is configured to be located on the same plane as the outer circumferential surface of the shoe hardware 1.

C is an outer tube slidably fitted around the outer periphery of the inner tube B, the lower end of which is made of a flexible material such as rubber, and is configured in advance to curve outward. An air barrier 6 is connected, and the lower end of the air barrier 6 is seated on the upper horizontal step of the bulge 4 .

Further, a pin 7 loosely inserted through the slit 5 of the inner tube B is attached between the core tube A and the outer tube C, and the pin 7 is normally in contact with the upper edge of the slit 5.

In the figure, 8 is a handle for fixing the outer tube C and core tube A when sliding the inner tube B, and 9 is a handle for sliding the inner tube B and for press-fitting the entire device into the ground. The handle 10 is an O-ring for preventing air from entering through the gap between the inner tube B and the core tube A.

Since the illustrated embodiment is constructed as described above, the core pipe A and both the inner and outer pipes B and C are press-fitted into the ground (see Fig. 6), and the inner pipe B is inserted into the ground so that the lower end of the slit 5 is Core tube A and outer tube C until they touch pin 7
When pulled up along the inner tube A, the slit 3 of the core tube A, which had been covered by the bulge 4 of the inner tube A, is exposed.
Gas in the soil enters the vertical through hole 2 through the slit 3, and enters the tube 11 connected to the upper end of the vertical through hole 2.
The gas is sampled into the gas sampling container 12 via the gas sampling container 12.

On the other hand, as the inner tube B is pulled up, its bulged portion 4
A flexible air barrier 6 is sandwiched between the upper end step and the lower end of the outer tube C. Therefore, the same air barrier 6
Since the gas is curved outward in advance, it bulges outward more and more and is compacted into the surrounding soil, preventing atmospheric air from mixing with the gas through the gap 13 created between the gas and the surrounding soil as the device is injected. will be prevented. (Refer to FIG. 7) As described above, according to the above-mentioned embodiment, underground gas can be easily collected with a simple configuration and without mixing with the atmosphere.

When extracting underground gas, the tube 11 is connected to the vertical through hole 2 of the core pipe A, and air is sampled via a vacuum pump 14, etc., but a cap 15 is attached above the handle 8 as shown in FIG. , insert septum 16,
Air may be collected using a syringe.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing one embodiment of the underground gas extraction device according to the present invention, and FIGS. Visual
6 and 7 are longitudinal sectional views showing the underground gas extraction process using the device of the present invention, and FIG. 8 is another embodiment of the underground gas extraction section. FIG. A...Core tube, B...Inner tube, C...Outer tube, 1...
Shoe hardware, 2... vertical hole, 3... slit, 4...
Swollen portion, 6... air barrier.

Claims (1)

[Scope of utility model registration request] A core tube that has a vertical through hole for air sampling in the center, a slit that communicates with the vertical through hole at the outer periphery of the lower end, and a metal fitting at the lower end, and a core tube that is slidably fitted to the outer periphery of the concentric tube. an inner tube having a bulge portion at its lower end that covers the slit portion of the core tube; An underground gas sampling device comprising an outer pipe that is curved and has a lower edge provided with an annular flexible air barrier that rests on the upper step of the bulging part of the inner pipe. .