JP2001193090A - Pit casing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pit casing capable of enhancing heat insulation effect in a casing and preventing frost heaving of the pit casing althrough a piping pit in a cold district is installed in a pit casing embedded in a hole excavated down to angeothermal retaining layer to escape freezing and the earth can be actually frozen to the same depth with the geothermal layer in the earth outside the casing and the heat insulation effect is decreased in half due to cold conduction and the casing rises up due to freezing of the embedded earth in a cold district or frost heaving projecting from the ground surface arises. SOLUTION: The peripheral wall of a heat insulation casing of a casing body is constituted of an outside casing 1a and an inside casing 1b to form a multiplex structure. The upper part of the multiplex space is closed by a heat insulation material 12 to form an air layer. The buried outer peripheral part is constituted of a low resistant raw material in accordance with frost heaving or covered with the low resistant raw material coating 13. Further, the peripheral wall of the heat insulation casing is widened to tapper off downward.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pit casing for preventing freezing of a pipe pit such as a flow meter, a water faucet and a water stopcock of a water pipe in a cold region.

[0002]

Conventionally, the setting of this type of pipe pit in a cold region is set to the same level as that of a water pipe buried at a depth of 1 to 1.5 meters underground to avoid freezing. For this reason, a large amount of labor and time are required, such as periodic meter reading, replacement of parts or maintenance and inspection cannot be performed without using a flashlight or a special jig.

[0003] Therefore, by the circulating effect of rising warm air due to geothermal heat and descending cool air due to cooling of the surface, the heat retaining state is maintained in the buried shallow layer at the upper part of the casing, and the water pipe buried in the deep part is reduced in the shallow part in the casing. The applicant has proposed a pipe pit casing (Japanese Patent Application No. 11-181353) in which a pipe pit can be set in a shallow part where the work can be performed directly from the ground surface.

[0004] However, the soil outside the casing of the pit casing may actually freeze to the same depth as the geothermal layer, and there has been a problem that the cooling air is conducted and the heat retaining effect in the casing is reduced by half.

Further, in a cold region, there is another problem that the casing rises due to freezing of the buried soil, and a frost heave phenomenon protruding from the ground surface occurs.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a multi-layer structure of a peripheral wall of a heat insulating casing to form an air layer on the peripheral wall. The upper portion of the gap is sealed with a heat insulating material.

That is, the air layer formed between the outer casing and the inner casing constituting the multi-layer structure serves as a heat insulating material, and the cool air received from the frozen soil by the outer casing is transmitted to the inside of the inner casing (geothermal layer). It was configured to suppress heat conduction.

Further, the buried outer peripheral portion of the pit casing main body is made of a low-resistance material such as reinforced plastic, or is covered with a coating made of a low-resistance material such as vinyl. In this case, the moving soil particles due to the expansion pressure slide on the outer peripheral surface of the main body so that the moving force of the moving soil particles does not act on the outer peripheral portion of the main body.

Further, the peripheral wall of the heat insulating casing is formed so as to expand downward in a tapered shape, and when the expansion pressure of the soil due to freezing is applied to the peripheral wall of the heat insulation casing, the moving soil particles due to the expansion pressure are formed by the tapered surface of the peripheral wall of the casing. The pit casing was pushed upwards to prevent frost heaving.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 denotes a pit casing body formed in a cylindrical shape, which is inserted and buried in the setting hole A excavated to the geothermal holding layer, and the bottom is released from the formation, and air is raised from the bottom of the setting hole A. Rising warm air is taken into the casing and circulates inside.

The pit casing body 1 has a double structure comprising an outer casing 1a and an inner casing 1b.
The upper portion of the gap formed by the double structure is sealed with the heat insulating material 12 so that air existing in the gap forms an air layer on the peripheral wall of the main body.

The outer casing 1a is made of a low-resistance material such as reinforced plastic, or is covered with a coating 13 made of a low-resistance material such as vinyl.
It is needless to say that this coating may be performed by covering or winding a plastic bag.

The lower end of the gap formed by the outer casing 1a and the inner casing 1b may have a structure in which geothermal heat can be utilized without providing a bottom plate, or a sole plate may be provided to serve as an air layer.

An outer casing 1a and an inner casing
The length of 1b can be set to each length corresponding to the freezing depth of the soil. For example, if the water pipe burial depth is 10
00 mm and freezing depth 600 mm, inner casing
The length of 1b is 1000 mm and the length of outer casing 1a is 60
It can be 0 mm.

At the lower end of the pit casing body 1, a primary (water supply) end 21 and a secondary (drainage) end 22 of the water distribution main pipe 2 embedded therein are inserted and fitted. twenty four
Is connected to

The rising pipes 23 and 24 are provided at their upper ends with connecting mechanisms 25 and 26 which are detachably connected to the primary side and the secondary side of a pipe pit B such as a flow meter, respectively, and are provided in the casing at an intermediate predetermined portion. It is supported and fixed by a supporting rod 11 provided.

Numeral 3 is a cover which is fitted with the upper end of the casing of the pit casing body 1 and covers the upper surface. The cover is made of reinforced plastic, and a heat insulating layer (not shown) made of a heat insulating material is formed on the required inner wall. An intermediate chamber 33 that covers the upper surface with an upper cover 35 that can be opened and closed, and that is fitted with a hollow sealing body 31 made of a heat insulating material, and that expands downward from its lower end in a tapered shape. And a heat insulating plate 34 constituting an inner lid is laid at the bottom of the intermediate chamber.

With this configuration, the inside of the hollow airtight body 31 is a low-temperature layer, and the intermediate chamber 33 is an intermediate layer. The relationship between the temperature inside the pit casing body, which is the geothermal layer, and the outside air temperature is adjusted. Note that the heat insulating plate 34 may be fitted to the upper end of the casing body without being set on the cover 3.

FIG. 2 shows another embodiment, in which the peripheral wall of a heat insulating casing composed of an outer casing 1a and an inner casing 1b is formed so as to expand downward in a tapered manner. In this configuration, as shown in FIG. 2, only the outer casing 1a may be configured to have a tapered shape, and the inner casing 1b may be configured to have a cylindrical shape.
The pit casing body 1 itself having a double structure may be formed in a tapered shape.

In the pit casing configured as described above, first, the setting hole A is excavated to the geothermal holding layer in which the water distribution main pipe 2 is buried, and the pit casing body 1 with the cover 3 removed is set to the setting hole A. A, the primary end 21 and the secondary end 22 of the water distribution main pipe 2 are inserted into the lower end thereof,
The rising pipes 23 and 24 are supported and fixed by the support rods 11, and each side end of the water distribution main pipe 2 is connected to the rising pipes 23 and 24.
Connecting the lower ends of the pipes, and the upper connecting mechanism of the riser pipes 23 and 24
The pipe pit B is connected between the rising pipes 23 and 24 by 25 and 26.

Next, the cover 3 incorporating the hollow sealing body 31, the heat insulating plate 34, etc., is attached to the ridge 41 of the fitting portion 4 and the main body 1.
The cover portion 3 is rotated by a predetermined angle to perform fastening, and the pit casing body is covered to fill the setting hole A back.

According to an experiment conducted by the applicant after setting the pipe pit casing, at a temperature of the outside air of -15.degree. C., the temperature of the low-temperature cover layer fitted with the hollow sealing body 31 is -6.degree. It has been confirmed that the upper intermediate layer is at -2 degrees C, and the heat insulation layer at which the piping pit B is set is at +3 degrees C.

Since the present invention is constructed as described above, even in a cold region where a water distribution main pipe is buried in a deep depth layer, a pipe pit is set in a shallow part where maintenance work and the like can be performed from the ground. In addition, it is possible to completely prevent the accident of freezing the pipe pit and the frost heave phenomenon.

[0024]

[Brief description of the drawings]

FIG. 1 is an overall vertical side view of a pit casing according to an embodiment of the present invention.

FIG. 2 is an overall vertical sectional side view of a pit casing in which a peripheral wall of a heat insulating casing according to another embodiment of the present invention is formed so as to expand downward in a tapered shape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pit casing main body 1a Outer casing 1b Inner casing 11 Support rod which supports riser pipe in the main body 12 Heat insulating material which seals the upper part of void 13 Coating made of low resistance material 2 Water distribution main pipe 21 Primary end of water distribution main pipe 22 Secondary end of water distribution main pipe 23, 24 Rise pipe 25, 26 Upper joint mechanism of rise pipe 3 Body cover 31 Hollow sealed body 32 Fitting part for fitting hollow sealed body 33 Taper expansion Intermediate room 34 Heat insulation plate that constitutes the inner lid 35 Upper lid of the cover lid A Setting hole in the pit casing body B Piping pit

Claims (3)

[Claims] 1. A heat insulating casing having an openable top cover and a bottom opening is set in a setting hole excavated to a geothermal holding layer, and in the heat insulating casing, a portion from a burying position of a buried pipe to a pit setting portion is provided. In the pit casing with pit joints provided at the water supply side end and the drainage side end that are configured by standing up, the surrounding wall of the heat insulation casing is configured in a multiplex structure, and the upper part of the multiplex gap is sealed with heat insulating material Pit casing characterized by being made 2. The pit casing according to claim 1, wherein a peripheral wall of the heat insulating casing is formed so as to expand downward in a tapered shape. 3. The pit casing according to claim 1, wherein the buried outer peripheral portion of the pit casing body is made of a low-resistance material, or is covered with a coating made of the low-resistance material.