JPH0748951A - Structure of buried type storage-tank roof - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object of the present invention to provide a structure of a buried storage tank roof that can improve the waterproof performance of a concrete roof regardless of changes in the outside temperature. [Structure] A roof 3 that is buried underground and closes the upper opening of a cylindrical storage tank with a bottom for storing low-temperature liquefied gas, a roof main body 4 that closes the upper opening of the storage tank 2, and an upper surface of the roof main body 4 The roof heater 5 is provided and configured.
By controlling the 0 ° C line above the roof body by this, a stable frozen soil layer is generated near the upper surface of the roof body 4 and a non-frozen area is secured above it to form the roof 3 Achieves improved water-stopping performance regardless of changes in outside air temperature, and prevents ups and weakening of the ground surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried tank roof structure for storing low temperature liquefied gas and the like.

[0002]

2. Description of the Related Art In a conventional low temperature liquefied gas underground storage tank, since the roof (made of steel) is exposed above the ground, a hot water heater or It is equipped with heating equipment such as a brine heater. However, in the above-mentioned low temperature liquefied gas underground storage tank, the roof is exposed to the ground, so that the roof is exposed to sunlight, and since the members that make up the roof are made of steel, the heat transfer coefficient is large, so The amount of heat input to the air increases and the amount of boil-off gas increases. Therefore,
In order to reduce the amount of boil-off gas generated, there is provided a low temperature liquefied gas underground storage tank in which the roof of the storage tank is made of concrete and completely buried underground.

[0003]

By the way, since it is well known that frozen soil has waterproofness and airtightness, it is stable on roof concrete regardless of external temperature changes. If the frozen soil can be generated, the waterproof performance is further improved in addition to the waterproof performance of the roof concrete itself. However, even if frozen soil is generated in the winter, it melts in the summer, the ground surface rises or softens, and the thickness of the frozen soil is not constant due to changes in the outside temperature. There was a problem. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure of a buried storage tank roof that can improve the water blocking performance of a concrete roof regardless of changes in the outside temperature.

[0004]

In order to achieve the above object, the structure of the buried storage tank roof of the present invention is such that the upper opening of a bottomed cylindrical storage tank that is buried underground and stores low-temperature liquefied gas and the like is closed. The roof is configured to include a roof main body that closes the upper opening of the storage tank, and a roof heater provided on the upper surface of the roof main body.

[0005]

In the structure of the buried storage tank roof of the present invention,
The roof heater controls the 0 ° C line above the roof body, thereby generating a stable frozen soil layer near the top surface of the roof body, and by securing a non-frozen region above the roof body, Achieves improved water-stopping performance regardless of changes in outside temperature, and raises the ground surface,
Prevent softening.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the structure of a buried storage tank roof according to the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment. In this figure, reference numeral 1 is an underground tank for storing low temperature liquefied gas. The underground tank 1 is composed of a storage tank 2 buried underground and a roof 3 that closes an upper opening of the storage tank 2. The storage tank 2 includes a bottom slab 2a formed of cast-in-place concrete or the like,
It comprises a cylindrical side wall 2b made of reinforced concrete or the like arranged on the bottom slab 2a or on the outer periphery of the bottom slab 2a. Has been done.

The roof 3 is mainly composed of a roof main body 4 formed on the upper edge of the side wall 2b and a roof heater 5 provided on the upper surface of the roof main body 4. Roof body 4
Is made of a concrete material such as reinforced concrete or prestressed concrete, and an airtight holding material and a cold insulating material 10 are applied to the inner surface thereof.

The roof heater 5 has a ring-shaped non-perforated metal tube 6 arranged concentrically on the upper surface of the roof body 4, a metal tube 6 arranged in a spiral shape, and the metal tube 6 arranged on the upper surface of the roof body 4. They are arranged in a mesh shape, and heat is supplied or absorbed by flowing a heat medium (hot water or the like) at room temperature or heated in the metal tube 6. On the other hand, on the ground where the roof 3 is buried, a heater station 7 having a pump for circulating the heat medium is installed, and the heater station 7 and the metal pipe 6 are connected by a transport pipe 8. ing.

In the structure of the buried storage tank roof having the above structure, hot water is flowed through the metal pipe 6 and circulated, and the 0 ° C. line is controlled above the roof body 4, that is, hot water of relatively high temperature is used in winter. By running a cold water in the summer and controlling the 0 ° C line above the roof body 4 in the summer, a stable frozen soil layer is generated near the upper surface of the roof body 4, and the top of the roof body 4 is not frozen. Reserve an area. Therefore, since the frozen soil layer is always kept in a frozen state regardless of the change in the outside temperature, it is possible to improve the water stopping performance of the roof 3 regardless of the change in the outside temperature, and at the same time, to freeze the frozen soil. Since a non-frozen region can be secured between the layer and the ground surface, it prevents the soil cover from rising or weakening due to the freezing of the low temperature liquid in the storage tank causing the cover soil to freeze or melt. be able to.

2 and 3 show a second embodiment of the structure of the buried storage tank roof according to the present invention. In this embodiment, a part of the heat insulating material 9 is laid under the roof heater 5 of the first embodiment. The heat insulating material 9 is formed of, for example, styrofoam, heat insulating concrete or the like having a low water absorption and a heat insulating property. When a heat insulating material having high water absorption is used, the outer peripheral portion of the heat insulating material is coated to prevent deterioration of the heat insulating performance due to water absorption.
Further, the thickness of the heat insulating material 9 is determined by the temperature of the stored liquid, the change in the outside air temperature, the thermal conductivity of the heat insulating material, and the like.

By laying the heat insulating material 9 as described above, it is possible to cope with changes in the thickness of the covering soil, the thickness of the roof main body 4, the thickness of the airtight holding material and the cold insulating material 10, the atmospheric temperature and the temperature in the storage tank. Thus, the above-mentioned 0 ° C line can be easily controlled.

[0012]

As described above, according to the structure of the buried storage tank roof of the present invention, the roof heater provided on the upper surface of the roof main body controls the 0 ° C line above the roof main body. By this, a stable frozen soil layer can be generated near the upper surface of the roof body, and an unfrozen region can be secured above it. Therefore, the frozen soil layer is always maintained in a frozen state regardless of the change in the outside temperature, so that it is possible to improve the waterproof performance as a roof regardless of the change in the outside temperature, and at the same time, to freeze the frozen soil layer. Since a non-frozen area can be secured between the ground surface and the ground surface, the cover soil does not freeze or melt due to the cold heat of the low temperature liquid in the storage tank, and therefore the ground surface is raised or weakened. Can be prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view of an underground tank, showing a first embodiment of the structure of the buried storage tank roof of the present invention.

FIG. 2 shows a second embodiment of the structure of the buried storage tank roof of the present invention, and is a side sectional view of a main part of an underground tank.

FIG. 3 is an enlarged view of an X circle portion in FIG.

[Explanation of symbols]

 1 Underground Tank 2 Storage Tank 3 Roof 4 Roof Main Body 5 Roof Heater 6 Metal Pipe 7 Heater Station 8 Transport Pipe 9 Insulation Material 10 Airtightness Holding Material and Cooling Material

Front Page Continuation (71) Applicant 000206211 Taisei Corporation 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo (71) Applicant 000174943 Mitsui Construction Co. 3-10-1 Iwamotocho, Chiyoda-ku, Tokyo (72) ) Inventor Masafumi Nakano 3-23-3, Kamijujo, Kita-ku, Tokyo (72) Inventor Yoshinori Kawamura 3-34-3, Akatsukashinmachi, Itabashi-ku, Tokyo Urban Life Yuri no Ki Dori East Building No. 305 Room (72) Invention Ken Shirasuna 2-3, Kandaji-cho, Chiyoda-ku, Tokyo Within Obayashi Corporation (72) Inventor Seiichi Oki 2-3-3 Kandaji-cho, Chiyoda-ku, Tokyo Inside Obayashi Corporation (72) Inventor Masamichi Yasunaga Tokyo Motojima Akasaka 1-2-7 Kashima Construction Co., Ltd. (72) Inventor Takeuchi et al. Motokakasaka 1-3-8 Kashima Construction Tokyo Branch of Tokyo (72) Inventor Kuroda Masanobu Shimizuura 1-3-2, Minato-ku, Tokyo Shimizu Construction Co., Ltd. (72) Inventor Junsei Sejima Tokyo 1- 2-3 Shibaura-ku, Shimizu Construction Co., Ltd. (72) Inventor Shoichi Watanabe 1-25-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Taisei Construction Co., Ltd. (72) Inventor Masayuki Moriya Nishi-Shinjuku, Shinjuku-ku, Tokyo 1-25-1 Taisei Construction Co., Ltd. (72) Inventor Masatoshi Kato 3-10-10 Iwamotocho, Chiyoda-ku, Tokyo Mitsui Construction Co., Ltd. (72) Inventor Muneki Watanabe Sanwa Iwamoto-cho, Chiyoda-ku, Tokyo 10-10-1 Mitsui Construction Co., Ltd.

Claims (1)

[Claims] 1. A roof structure which is buried underground and closes an upper opening of a bottomed cylindrical storage tank for storing low-temperature liquefied gas and the like, wherein the roof has a roof main body which closes the upper opening of the storage tank. A structure of an embedded storage tank roof, comprising: a roof heater provided on an upper surface of the roof body.