JP2001164787A - Roof unloading method when putting tank on roof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform unloading easily, rapidly, and inexpensively and hence balance a tank roof securely by using a crane that can travel such as a track crane that is known conventionally when performing the air raising of the tank roof, and suspending a part with large weight per the unit area of the tank roof. SOLUTION: A part to be unloaded of a tank roof 1 is suspended by a wire rope 9 that is suspended from a boom 7c of a track crane 7 that is arranged close to a tank body 2, the wire rope 9 is taken up by a traction machine 8e while it is suspended from the tip of a boom 8c of a track crane 8 that is provided separately from the tank body 2, and a counter weight 12 with nearly the same weight as a load to be unloaded of the tank roof 1 is suspended at the lower end being suspended from the tip of the boom 8c of the wire rope 9 via a sheave 8g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for unloading a roof when a tank roof is lifted.

[0002]

2. Description of the Related Art For example, when mounting a tank roof of an underground tank on an upper portion of a tank body, an air-raising method using air pressure is performed. FIG. 5 shows an outline of an example of a case where the tank roof is air-raised. FIG.

That is, in the air-raising method, as shown in FIG. 5, after a tank roof 1 is assembled at the bottom of a tank body 2, a sealing member is attached to an outer peripheral edge of the tank roof 1, and a blower or the like arranged on the ground is used. The compressed air 5 is introduced to the lower side of the roof 1 by the air supply means 3 through the air supply pipe 4, and the tank roof 1 is floated by air pressure and supported on the tank body 2.

However, since the tank roof 1 has a different weight per unit area depending on the location, in the case of such an air-raising method, the tank roof 1 may be inclined at the time of floating, and it is difficult to hold the tank roof 1 horizontally. Therefore, when the tank roof 1 floats, it is necessary to maintain a balance so that the tank roof 1 does not tilt.

FIG. 6 is a schematic longitudinal sectional view of an example of a conventional means for maintaining a balance so that the tank roof does not tilt when the tank roof floats. In FIG. 6, in order to prevent the tank roof 1 from tilting when ascending, the tank roof 1 must be
Balance weight 6 on the part with light weight per unit area
And aerating is performed by balancing the weight of the entire tank roof 1.

Further, in order to maintain the balance so that the tank roof does not tilt when ascending, a substantially vertical column supported by a side cable, a pulley at the top, and a winder at the leg are provided. It is conceivable that the tank roof is supported by a wire rope wound by a leg winder using a gin pole provided with a fin.

[0007]

SUMMARY OF THE INVENTION In the conventional method,
As shown in FIG. 6, when the balance weight 6 is loaded on the lightweight portion of the tank roof 1, the tank roof 1 needs to have rigidity capable of withstanding the weight of the balance weight 6. There is a problem that the total weight increases.

If a ginpole is used, a foundation is required and the ginpole must be removed after the construction is completed, which may increase the construction cost. Not valid.

In view of such circumstances, the present invention uses a movable crane, such as a conventionally known truck crane, to suspend a portion of the tank roof having a large weight per unit area when air-raising the tank roof. By lowering,
It is an object of the present invention to easily, quickly and at low cost unload a portion having a large weight per unit area of the tank roof and to surely maintain the balance of the tank roof.

[0010]

SUMMARY OF THE INVENTION The present invention provides a method of unloading a tank roof when the tank roof is lifted so that the tank roof does not tilt when the tank roof is raised in the tank body by air-raising. A rope suspended from a boom of a first crane disposed close to a tank body is inverted at a lower end portion, and is extended from a boom of the first crane to a boom of a second crane. Hang down from the boom of the second crane and invert at the lower end so that it can be wound by the hoist of the second crane, and a tank roof is attached to the lower end of the rope hung from the boom of the first crane. And the counterweight is hung on the lower end of the rope suspended from the boom of the second crane.

In the present invention, the load to be unloaded at the unloading location on the tank roof and the weight of the counterweight are preferably substantially the same.

In the present invention, it is preferable that the first and second cranes are configured to be movable.

According to the present invention, when the tank roof is air-raised, the load on the tank roof can be easily and quickly reduced at low cost by suspending the tank roof.
The balance of the tank roof can be reliably maintained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show an embodiment of the present invention. FIG. 1 shows a state of unloading a tank roof when there is a single unloading section having a large weight per unit area of the tank roof. FIG. 2 is a schematic diagram showing how a wire rope is wound around two truck cranes, and FIG. 3 is a schematic diagram of a truck crane which is disposed at a position separated from the tank body during the work. It is a vector diagram which shows the state of the acting force.

In FIG. 1, reference numerals 7 and 8 denote conventional well-known truck cranes.
a, 8a; revolving bodies 7b, 8b rotatably mounted on the traveling bodies 7a, 8a; booms 7c, 8c disposed undulatingly on the revolving bodies 7b, 8b; and supporting the truck cranes 7, 8 during work. Outer rigs 7d and 8d, a hoist, and the like. 1 and 2 show a truck crane 8.
The hoisting machine mounted on the revolving superstructure 8b is indicated by reference numeral 8e.

Next, the operation of the above illustrated example will be described.

When the tank roof 1 is lifted by the air-raising method and the load of the heavy portion per unit area of the tank roof 1 is to be unloaded, as shown in FIG. The traveling body 7a is stopped at a position close to the tank body 2 with the traveling body 7a supported by the outrigger 7d, and the traveling body 8a is moved by the outrigger 8d to a position away from the tank body 2 by a predetermined distance from the second truck crane 8. Stop with support.

In this case, the truck crane 7 has its front part directed toward the tank body 2, and the boom 7c is
At the front of the tank body 2 is inclined in an upward slope toward the tank body 2 side. The truck crane 8 has its front part directed away from the tank body 2, and the boom 8 c is inclined at the front part of the truck crane 8 upwardly in the direction separated from the tank body 2.

The wire rope 9, one end of which is fixed to the tip of the boom 7c of the truck crane 7 hangs down, is wound around the sheave 7e of the sheave block at its lower end, and turns upward and extends upward. The truck crane 8 is wound around a sheave 7f provided at the tip of the truck crane 8 and extends slightly downward toward the sheave 8 provided at the tip of the boom 8c of the truck crane 8. A hook 7g is attached to a sheave block provided with a sheave 7e, which is provided at a lower end portion of the wire rope 9 below the tip of the boom 7c.
A portion of the tank roof 1 where the excessive load F is to be unloaded is suspended from the hook 7g via a wire rope 10.

A wire rope 9 wound around a sheave 8f provided at the tip of a boom 8c of a truck crane 8
Hangs around the sheave 8g of the sheave block at its lower end, turns over and extends upward, is wound around a sheave 8h provided at the tip of the boom 8c, extends diagonally downward, and is a truck crane. 8 is wound by a hoisting machine 8e. A hook 8i is attached to a sheave block provided with a sheave 8g, which is provided at the lower end of the wire rope 9 below the tip of the boom 8c.
, A counterweight 12 having a weight W is suspended via a wire rope 11. The weight W of the counterweight 12 is substantially the same as the load F of the tank roof 1 to be unloaded.

When air-raising the tank roof 1 having the load F to be unloaded, pressurized air 5 is assembled at the bottom of the tank body 2 from the air supply means 3 shown in FIG. It is introduced below the tank roof 1. Therefore, the tank roof 1 starts to float along the tank body 2 by air pressure.

When the tank roof 1 starts to float along the tank body 2, the wire rope 9 is sent from the truck crane 7 to the truck crane 8, so that the wire rope 9 is lifted by the hoisting machine 8e of the truck crane 8. Winding is performed at a speed approximately twice as high as the floating speed of 1.

Accordingly, the boom 8c of the truck crane 8
The counterweight 12 hung on the hook 8i of the sheave block located below holds a substantially constant height position, and the counterweight equal to the load F which is always unloaded at the unloading point of the tank roof 1. The weight W of the weight 12 acts stably.

As a result, the excessive load F of the tank roof 1 is offset by the weight W of the counterweight 12 and is surely unloaded, so that the tank roof 1 can be easily and reliably balanced when the tank roof 1 is air-raised. It is possible to stably perform air-raising while always holding the tank roof 1 horizontally.

Further, since the excessive load F of the tank roof 1 and the weight W of the counterweight 12 are offset, it is not necessary to increase the rigidity of the tank roof 1, so that the weight of the tank roof 1 does not increase and the hoisting machine Since the hoisting power of 8e may be small, labor saving can be achieved.

As shown in FIG. 1, when two tank cranes 7 and 8 are used to maintain the balance of the tank roof 1, a load acting on the sheaves 8f and 8h on the same horizontal axis of the truck crane 8 is used. Is equal to the weight W, a tension of W / 2 acts on a portion of the wire rope 9 that is stretched between the sheave 8f of the truck crane 8 and the sheave 7f of the truck crane 7, and the load W and The resultant WO with the tension W / 2 is a vector V in the direction shown in FIG.
At a position lower than the tilt position of the boom 8c.

This is to prevent the truck crane 8 from being pulled toward the tank body 2 by the tension acting on the wire rope 9 between the sheaves 8f and the sheaves 7f and the front wheel side of the traveling body 8a from floating.

In the illustrated example, two truck cranes 7 and 8 are used at one location where the load F of the tank roof 1 is to be removed, for the following reason. FIG. 4 is a schematic work diagram showing how the unloading unit having a large weight per unit area of the tank roof is unloaded by one truck crane when the tank roof is air-raised.

In FIG. 4, the same reference numerals as those shown in FIG. 1 denote the same parts, and 7h is installed on a traveling body 7a of a truck crane 7 to wind up a wire rope 9. The hoisting machine 7i, 7j is a sheave arranged in the middle of the boom 7c in the longitudinal direction, and 7k is a wire rope 9 hung by being guided by the sheaves 7i, 7j.
The sheave 7l located at the lower end of the counterweight 12 is attached to a sheave block in which the sheave 7k is arranged.
This is a hook that suspends.

As shown in FIG. 4, when one place on the tank roof 1 is unloaded by one truck crane 7,
The tank roof 1 is suspended by one truck crane 7, and a hanging part is formed in the middle of the wire rope 9 wound and fed by the hoisting machine 7h of the truck crane 7,
The work is performed by suspending the counterweight 12 at the lower end of the hanging part.

In this case, it is theoretically possible to maintain the balance of the tank roof 1 at the time of air lasing. However, both the load F of the tank roof 1 and the weight W of the counterweight 12 are supported by the boom 7c. There is a need to. For this reason, it is necessary to increase the rigidity of the boom 7c of the truck crane 7, and the overturning moment of the truck crane 7 is also increased. As a result, the standard truck crane 7 cannot be used and the cost may be increased. There is. Accordingly, it is not preferable to maintain the balance of the tank roof 1 by one truck crane 7 as shown in FIG. 4 when the tank roof 1 is air-raised.

In the roof unloading method of the present invention, a truck crane is used as a movable crane. However, in the case of a traveling crane, various conventionally known cranes can be used. It goes without saying that various changes can be made without departing from the scope of the present invention.

[0034]

As described above, the first aspect of the present invention is as described above.
According to the roof unloading method at the time of tank roof lifting described in ~ 3,
When aerating the tank roof, the excellent effect of suspending the tank roof, removing the load on the tank roof easily, quickly and at low cost, and maintaining the balance of the tank roof reliably. I can play.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of a method of unloading a roof when a tank roof is lifted according to the present invention, wherein unloading of a tank roof is performed in a case where there is one unloading portion having a large weight per unit area of the tank roof. It is a work outline figure showing a situation.

FIG. 2 is a schematic diagram showing how a wire rope is wound around two truck cranes in the method of unloading a roof when the tank roof is lifted in FIG. 1;

FIG. 3 is a vector line showing a state of a force acting on a truck crane, which is disposed at a position separated from a tank body during operation, of two truck cranes in the method of unloading a roof from a tank according to the present invention. FIG.

FIG. 4 is a schematic work diagram showing a state in which the unloading portion of the tank roof is unloaded by one truck crane when air-raising the tank roof.

FIG. 5 is a longitudinal sectional view showing an outline of an example of a case where the tank roof is air-laminated.

FIG. 6 is a schematic vertical sectional view of an example of a conventional means for maintaining a balance so that the tank roof does not tilt when the tank roof floats.

[Explanation of symbols]

 Reference Signs List 1 tank roof 2 tank body 7 truck crane (first crane) 7c boom 8 truck crane (second crane) 8c boom 8e hoisting machine 9 wire rope (rope) 12 counterweight F load W weight

Claims (3)

[Claims] 1. A method of unloading a tank roof when lifting the tank roof so that the tank roof does not tilt when the tank roof is raised into the tank body by air-raising. The rope hanging down from the boom of the first crane arranged in reverse is inverted at the lower end, and then extended from the boom of the first crane to the boom of the second crane, from the boom of the second crane. Hang it at the lower end so that it can be taken up by the hoist of the second crane, and suspend the unloading point of the tank roof at the lower end of the rope hung from the boom of the first crane. A method of unloading a roof when lifting a tank roof, wherein a counterweight is hung on a lower end of a rope suspended from a boom of the second crane. 2. The method according to claim 1, wherein the load to be unloaded at the unloading point of the tank roof is substantially equal to the weight of the counterweight. 3. The method according to claim 1, wherein the first and second cranes are movable.