JPS6352198B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a foam generating device used in air drilling type drilling work.

[Technical Background of the Invention] Air drilling methods have been known in which air is pumped into a hole during drilling work to cool the tip of the drill bit inserted into the ground and to transport rock powder out of the hole. As an improvement to this air drilling method, a drilling method is already known in which rock powder is more smoothly discharged from the hole by sending bubbles into the hole together with air.

In this type of air drilling method that uses foam, it is necessary to feed the foam together with air to the tip of the drill, and the device for this purpose is an injection pump that sends a foaming agent into the hole and foams the foam inside the hole. Alternatively, a blowing agent is supplied into an air hose that sends compressed air into the hole, and the bubbles generated in the air hose are sent into the hole together with the air.

Of these, regarding the latter,
There are inventions described in Publication No. 49-6961 and Japanese Patent Publication No. 52-31281.

[Problems with the Background Art] However, the invention described in Japanese Patent Publication No. 49-6961 supplies the blowing agent directly and dripping into the air hose that feeds compressed air to the tip of the drill bit, and therefore The diameter of the bubbles formed in the hole is non-uniform, and the bubbles supplied into the hole cannot sufficiently adsorb rock powder, resulting in the disadvantage that the rock powder cannot be effectively discharged from the hole. In other words, the reason why rock powder is discharged by bubbles is that old bubbles with rock powder attached to the surface are pushed up to the entrance of the hole by new bubbles supplied to the bottom of the hole. The ability of foam to adsorb rock powder depends on the size, viscosity, surface tension, etc. of the foam. These are influenced by the properties and concentration of the foaming agent itself, but if the same foaming agent is used, it largely depends on the suitability of foaming.

However, when a linear foaming agent is supplied into the air hose as described above, the mixing ratio of the foaming agent and air fluctuates due to fluctuations in the air pressure of the air hose during the drilling operation, resulting in uneven shapes of the bubbles and pores. When the rock powder is supplied into the hole, the ability of each bubble to adsorb rock powder may be insufficient or too large, and the bubbles may be crushed during discharge from the hole, resulting in the inconvenience that the rock powder cannot be discharged smoothly. In addition, when the foaming agent is dropped into the air hose, that is, when it is supplied drop by drop using gravity, the foaming agent does not foam immediately inside the air hose because the particle size of the foaming agent is large.
Since foam accumulates on the inner wall of the air hose and then foams, the foam is gradually peeled off from the wall of the hose by the pressure of the air flowing through the air hose and is supplied into the hole. There was a drawback that bubbles of uniform shape could not be formed within the air hose. Moreover, since this invention drips the foaming agent in the tank directly into the air hose, when the amount of foaming agent in the tank decreases, the supply pressure decreases and the amount of foaming agent supplied into the air hose decreases. Therefore, there was an inconvenience that the mixing ratio of air and blowing agent became incorrect as time progressed.

On the other hand, the invention described in Japanese Patent Publication No. 52-31281 is
The blowing agent in the blowing agent tank is supplied into the air hose by utilizing fluctuations in the air pressure inside the air hose due to the drilling operation. Indeed, in this invention, the amount of blowing agent supplied into the air hose changes as the air pressure fluctuates, so this invention is superior to the above-mentioned inventions. Moreover, the method of supplying the foaming agent is not by dripping, but by providing an inlet hole where dynamic pressure is applied and an outlet hole where static pressure is applied in the air hose, and using the differential pressure between them, the foaming agent is injected into the air hose.
The inconvenience caused by dripping has been resolved.

However, this invention is similar to the above-mentioned invention in that the blowing agent is directly injected into the air hose where the pressure fluctuates as a result of the drilling operation, and even if the blowing agent supply amount is adjusted as the air pressure fluctuates. However, there was a drawback that it was not possible to obtain proper foam. In particular, in this invention, the amount of blowing agent supplied to the air hose is adjusted by the differential pressure between the dynamic pressure and the static pressure inside the air hose, but during actual drilling work, the air pressure in the air hose repeatedly fluctuates in an extremely short period of time. When the pressure of the air hose is used directly as in this invention, the blowing agent is supplied intermittently, and a phenomenon occurs in which a large amount of blowing agent comes out momentarily and then the supply is stopped. Between the bubble generator and the tip of the cone, dense bubbles with a small diameter are formed alternately when a large amount of blowing agent is supplied, and loose bubbles are formed when there is a small amount of blowing agent. As a result, the foam supplied to the tip of the drill became non-uniform, resulting in a decrease in the ability to deposit and discharge rock powder.

In this way, in order to generate uniform foam with excellent adhesion ability for rock powder, it is necessary to keep the supply amount of the blowing agent and air constant at all times, and the above two inventions both solve this problem. The points were not satisfied.

[Object of the Invention] The present invention was proposed to solve the problems of the prior art as described above, and its purpose is to provide a uniform foam with excellent adhesion ability for rock powder to the tip of the drill bit. The object of the present invention is to provide a foam generating device that can generate foam.

[Summary of the Invention] The foam generating device of the present invention focuses on the fact that the drawbacks of conventional foam generating devices are that the foaming agent is directly supplied into the digging air hose. By providing a separate air hose for foam generation, and supplying a fixed amount of foaming agent into the air hose from a metering tank into which a fixed amount of foaming agent is always injected, a fixed amount of air and foaming agent can be used. This makes it possible to obtain uniform foam at all times.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 shows an example of a foam generating device of the present invention and an air excavation device using the same.

In the figure, 1 is a boring machine for drilling, 2 is its rod, and 3 is a sampler tube attached to the tip of the rod 2. The main compressor 4 is located at the upper end of the rod 2.
A digging air hose 5 extending from the hole is connected, and compressed air is supplied to the tip of the drill bit 3 through the air hose 5. A foam supply air hose 7 extending from a foam generation compressor 6 is connected to the middle of this digging air hose 5, and a foam generation device 10 of the present invention is provided midway along this foam supply air hose 7.

The foam generating device of the present invention has, for example, a structure as shown in FIG. 2, and includes a metering tank 11 supported by leg portions 11a. This quantitative tank 11 is connected to a larger supply tank 12 supported by legs 12a and a connecting pipe 13.
connected via. This supply tank 12 has its bottom above the liquid level of the metering tank 11, and the supply tank 13 is connected to the metering tank 1.
A blowing agent is supplied to 1. A float 14 is provided in the metering tank 11, and this float 14 is connected to a control valve 15 provided at the outlet of the connecting pipe 13. When the liquid level of the blowing agent in the metering pipe 11 decreases, this control valve is activated. 15 is now open.

Further, an atmosphere opening hole 16 is provided above the liquid level of the metering tank 11, so that atmospheric pressure is applied to the inside of the metering tank 11 at all times. On the other hand, a blowing agent inlet 17 having an air vent hole 18 and an air vent valve 19 are provided in the upper part of the supply tank 12, and a liquid level meter 20 is further provided on the side.

On the other hand, the lower end of a liquid feeding pipe 21 is connected to the bottom of the metering tank 11, and the tip of this liquid feeding pipe 21 opens into the foam supplying air hose 7. In addition, a drain pot 22 is provided in the middle of the liquid sending pipe 21 and the connecting pipe 13. Liquid feeding pipe 21
An adjustment valve 23 for adjusting the supply amount of the foaming agent is provided at the opening of the foam supply air hose 7, and the opening of the liquid feed pipe 21 in the foam supply air hose 7 is equipped with a ventilator having a smaller diameter than other parts. 24. Further, a window 25 for monitoring the state of the foam in the foam supply air hose 7 is provided on the foam discharge side of the liquid sending pipe 21 of the foam generation air hose 7.

In the foam generating device of this embodiment having such a configuration, as shown in FIG.
At the same time, the compressed air from the foam compressor 6 is sent to the foam generator 10, and the foam generated here is sent to the foam generator 10 through the air hose 5. It is supplied into the drilling air hose 5 through the drilling air hose 5, and is sent to the drilling tip together with the drilling compressed air inside, to discharge rock powder from the drilling hole.

On the other hand, in the foam generator itself, as shown in FIG. 2, the foaming agent from the metering tank 11 is supplied into the foam supply air hose 7 through the liquid feed pipe 21. At this time, a fixed amount of foaming agent is always injected into the metering tank 11 by the float 14 and the control valve 15, and even if the foaming agent is supplied into the air hose 7, the height of the liquid level in the metering tank remains constant. Since this does not change, the supply pressure from the metering tank 11 into the air hose does not change, and a constant amount of foaming agent can be supplied at all times. In this manner, the foaming agent supplied into the air hose is sprayed into the air hose in the form of a mist by the action of the ventilator 24 provided at the outlet of the liquid sending pipe 21, and is immediately foamed.

At this time, unlike the two inventions shown as prior art, the air hose that supplies the foaming agent is provided exclusively for foam generation, so it is less affected by pressure fluctuations like the air hose for digging. Furthermore, since the amount of foaming agent supplied to the air hose 7 is kept constant by the action of the metering tank 11, uniform foam can be formed at all times with a fixed amount of air and the foaming agent.

Furthermore, unlike the conventional invention of Japanese Patent Publication No. 52-31281, there is no inconvenience caused by fluctuations in the amount of foaming agent supplied due to pressure fluctuations in the air hose for excavation, so foam is not concentrated in the air hose. It is possible to always supply uniform foam to the tip of the drill. In addition, unlike the invention of Japanese Patent Publication No. 49-6961, the foaming agent was sprayed out in the form of mist using a ventilator instead of dripping, so the foaming agent could be foamed immediately, which was different from previous inventions. The disadvantage of non-uniform foaming caused by adhesion to the inner wall of the air hose is also eliminated.

Furthermore, in the illustrated embodiment, a monitoring window 25 is provided on the air hose 7, and an adjustment valve 23 is provided at the opening of the liquid feed pipe 21, so that the air hose 7 is provided with a monitoring window 25, and an adjustment valve 23 is provided at the opening of the liquid feeding pipe 21. When using various types of blowing agents, there is also the advantage that the foam condition can be monitored and the amount of blowing agent supplied can be adjusted accordingly.

Note that the present invention is not limited to the above-described embodiments, and the blowing agent may be supplied to a metering tank using a pump or the like as a supply source of the blowing agent.

[Effects of the Invention] As described above, according to the foam generating device of the present invention, since an air hose exclusively for foam is provided and a fixed amount of foaming agent is always supplied using a metering tank, rock powder in the hole can be reduced. It has the effect of generating bubbles with excellent adhesion and removal ability.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an overview of an air excavation method using the foam generating device of the present invention, and FIG. 2 is a sectional view showing an embodiment of the foam generating device of the present invention. 1... Boring machine, 2... Rod, 3... Awl,
4... Main compressor, 5... Air hose for digging, 6... Compressor for foam generation, 7... Air hose for foam generation, 10... Foam generator, 11... Metering tank, 12... Supply tank, 13... Connection pipe, 14
...Constant pressure switch, 14...Float, 15...Control valve, 21...Liquid feed pipe, 23...Adjustment valve, 24...
Ben Yuri, 25...Surveillance window.

Claims (1)

[Claims] 1. A metering tank injected with a blowing agent is connected to a supply source of the blowing agent via a connecting pipe, and the connecting pipe is provided with a control valve that operates in conjunction with a float in the metering tank, and the float The liquid level of the foaming agent in the metering tank is maintained constant using a control valve and a foam generating air hose is provided in a separate system from the excavating air hose, and a liquid feed line extending from the bottom of the metering tank is installed inside this foam generating air hose. A foam generating device characterized by having an open end of a tube. 2. The foam generating device according to claim 1, wherein the opening of the liquid feeding pipe in the foam generating air hose is a ventilate. 3. The foam generating device according to claim 1, wherein the liquid feeding pipe has a valve for adjusting the supply amount of the foaming agent.