JPS6025879A - Apparatus for absorbing freezing expansion force in tank - Google Patents

Abstract

PURPOSE:To enable protection of a structure eliminating the need for an antifreezer by keeping a frame-shaped float made of an elastic material floating half-submerged on the surface of a liquid in a tank to absorb a freezing expansion force in the tank. CONSTITUTION:A frame-shaped float 6 made of an elastic material is kept floating half-submerged on the surface of a liquid in a tank 4. When a seawater ballast 5 in the tank 4 is frozen at the water surface portion, a volumetric expansion develops. But since the frozen water surface is demarcated with a lattice-shaped float 6, the frozen volume is subdivided to reduce the freezing expansion force. Then, the elastic deformation of the float 6 allows the partial absorption of the freezing expansion force to reduce the freezing expansion force to be transmitted to a hull.

Description

[Detailed description of the invention] TECHNICAL FIELD This invention relates to an apparatus for absorbing freezing expansion force within a tank.

For example, seawater in a ballast tank of a ship navigating in an icy area or a marine structure installed in an icy area expands in volume when it solidifies, and the expansion rate is as high as 1.1 to 1.3. Therefore, as the frozen volume increases, the force exerted by its expansion force on the structure also increases, and steel materials at low temperatures are susceptible to brittle fracture, and these factors may combine to cause the structure to fail. be.

To prevent this, it is possible to install an anti-icing device in the tank, but this requires enormous equipment and maintenance costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for absorbing freezing and expanding force in a tank that can protect structures by absorbing the freezing and expanding force of liquid in the tank.

The device according to the present invention is characterized in that a frame-shaped buoyant body made of an elastic body is floated on the liquid level in a tank in a semi-submerged state.

In this specification, frame-shaped buoyant bodies include both those in which the inner section of the frame is not divided at all and those in which the inner side of the frame is divided into a plurality of sections.

According to this invention, even if the liquid in the tank freezes, the frame-shaped buoyant body floating semi-submerged on the liquid surface elastically deforms, thereby absorbing the freezing expansion force. Therefore, the structure can be protected from destruction due to freezing expansion force without using a conventional anti-icing device. In addition, even if the height of the liquid level in the tank changes, the buoyant body will naturally follow this change and reliably absorb the freezing and expansion force of the liquid level, making it easy for people to adjust the height of the buoyant body. There's no need. Furthermore, the structure of the buoyant body is a simple frame-like structure, and since no power is required to use it, and there is no need to use an anti-icing device as described above, it is extremely economical.

It is preferable that the buoyant body has a frame divided into a plurality of sections. In this way, the freezing volume is subdivided by the buoyant bodies, so the freezing expansion force is reduced, and the freezing expansion force can be sufficiently absorbed by the many elastic bodies that divide the inside of the frame.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a cross section of an oil tanker, whose tank hull (1) is divided by transverse bulkheads into a bow section, a stern section, and a tank section between them. The tank portion is divided into a plurality of front and rear compartments by a plurality of horizontal bulkheads, and these compartments are divided into a center tank (3) and side tanks (4) by two rows of vertical bulkheads (2).

The center tank (31) is usually used as a tank exclusively for cargo oil.In addition, the side tanks (4) include those used as tanks exclusively for ballast and those that serve both as a cargo oil tank and a ballast tank. .

When the seawater ballast (5) is mounted on the side tank (4), a rubber buoyant body (6), which constitutes an absorption device for freezing expansion force, is floating on the water surface in a semi-submerged state. Buoyant body (
6) is a grid-like structure in which the inside of a rectangular frame is divided into a plurality of sections vertically and horizontally. As shown in detail in FIGS. 2 and 3, each part of the buoyant body (6) has a substantially isosceles triangular cross section, and air is sealed in a hollow part (7) formed inside the buoyant body (6). This hollow part (7) is intended to give an appropriate buoyancy to make the buoyant body (6) semi-submerged, and if this alone is insufficient to adjust the semi-submerged state, the buoyant body (6) ) A buoyancy adjustment piece (8) is attached to an appropriate position. As a result, even if the height of the water surface of the seawater ballast (5) changes, the buoyancy body (6) naturally follows it and always floats in a semi-submerged state on the water surface.

As shown in Figure 1, there is a relatively large bone mass (9) in the tank (4).
) are protruding, one or more buoyant bodies (6) for each section of water surface divided by aggregates (9).
is placed.

When the water surface of the seawater ballast (5) in the tank (4) freezes, volumetric expansion occurs. However, since the frozen water surface is divided by the lattice-shaped buoyancy bodies (6), the frozen volume is divided into smaller parts, and therefore the freezing expansion force is also reduced. By elastically deforming each part of the buoyancy body (6), this freezing expansion force is absorbed, and the freezing expansion force transmitted to the hull il+ becomes extremely small. In addition, a buoyant body (
6) Since the cross section of each part is approximately an isosceles triangle, the expansion of the ice can be released upward along the slope.

Note that the height, width, etc. of each part of the buoyancy body (6) are appropriately determined depending on the expected ice thickness.

When the center tank (3) is loaded with seawater ballast or a liquid that tends to freeze, the buoyant body (6) is similarly floated on the liquid surface.

The planar shape, cross-sectional shape of each part, material, etc. of the buoyancy body (6) are not limited to those of the above embodiments, and can be changed as appropriate.

Further, the present invention can be applied to tanks other than oil tanker tanks, and can also be applied to liquids other than water.

[Brief explanation of drawings]

The drawings show an embodiment of the invention, and FIG. 1 is a cross-sectional view of an oil tanker equipped with a freezing expansion force absorption device according to the invention;
FIG. 2 is a partially enlarged perspective view of the buoyancy body, and FIG. 3 is a cross-sectional view of the same. (41-... Tank, (61-... Buoyant body.

Claims (1)

[Claims] A device for absorbing freezing and expansion force in a tank, characterized in that a frame-shaped buoyant body (6) made of an elastic body is floated in a semi-submerged state on the liquid level in the tank (4).