JPS6132200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transportation method and apparatus for transporting a boiler installed on a ship or barge after assembly on a sea or a river, and particularly for preventing resonance of the boiler due to waves.

Examples of large-scale transportation items installed on barges or ships include boilers, petroleum cracking plants, large reaction towers, and the like. In addition, there are many tanks associated with black liquor recovery boilers for power generation in pulp mills. Calculations and actual measurements have shown that the natural vibration period of these devices is one to several seconds.

In contrast, the oscillation period of waves in the ocean has been measured from ripples that last less than one second to large swells that last several tens of seconds. Therefore, during transportation, waves with a period that causes resonance in these devices are quite commonly encountered.

For this reason, conventional methods have been used to predict the frequency and period of waves received during transportation by surveying the ocean currents, climate, seafloor topography, etc. of the transportation area and actually measuring the wave frequency, and to avoid resonance with that frequency. We designed a boiler with a natural frequency and made it extremely strong just in case, while choosing calm weather for transportation and avoiding routes with steep ocean currents. , many difficult problems arose. However, sometimes the weather can change suddenly,
There was a high risk of being hit by unexpected waves, or of damage due to resonance if the waves did not subside even when the weather improved, so there was no other option other than to make large transport items fairly strong.

The object of the present invention is to propose a water transport method and an apparatus therefor that avoid resonance due to the above-mentioned daily waves or unexpected waves and prevent damage caused by resonance of a large transported object.

In short, the present invention is characterized by a method and apparatus for supplying water into an airtight space of a large-scale transport object and utilizing the inertia of the water to prevent resonance of the large-scale transport object.

An embodiment of the present invention will be described below with reference to the drawings, taking a boiler as an example. In Figures 1 to 3, 2
The space inside the heavy bottom 3 is a ballast tank 5 of a barge or ship, and the water 5' in this ballast tank 5 is pumped up by a pump 7 and supplied to an airtight space, such as a furnace 6, via a water supply pipe 7a. When this water is drained and the water level is adjusted, the valve 8 provided in the drain pipe 8a is opened and closed. The drained water is returned to the ballast tank 5. Also, if necessary, the pump 7 is activated to replenish water to the furnace 6.

In addition to the above-mentioned ballast tank, the storage tank for water supplied to the airtight space of a large transport object for carrying out the present invention includes a heavy oil tank, a tank for a water production system, and the like. In order to maintain a ship's metacenter, it is desirable to use a tank located low on the ship's deck as a storage tank.

Portions in the boiler 1 that are susceptible to vibration, such as superheater tubes and evaporator tubes, are equipped with stays 9 or other restraint devices or vibration isolation devices to ensure safety during transportation. Further, the boiler body is supported on the steel frame 10 by stays 9' in the vertical direction (pitting direction) and the horizontal direction (rolling direction). The tube group drums of the superheater, etc. are suspended from the ceiling steel frame by slings 11, but there is no pendulum-like vibration due to restraint means, and the vibration is integrated with the steel frame via the stay. forming a system.

Generally, the vibration period of the water 12 supplied to the furnace is determined by the shape and depth of the furnace, which is the container containing the water. In order to change the vibration period, it is effective to limit the vibration of the upper part of the reservoir water. For example, as shown in Fig. 4, in an example assembled from members that are lighter and stronger than water, a stored water resonance prevention device 13 having a part hanging down from the water surface is installed to reduce vibrating free water near the water surface to an appropriate size. By dividing the water into two parts, the natural vibration period of water can be manipulated.
If the vibration period of the water 12 is smaller than the natural period of the boiler 1 and does not resonate with the boiler, the inertia of the water can be prevented from resonant vibration of the boiler when the boiler resonates or is close to resonance with the wave excitation period. can give you the power to The force generated by the inertia of this water dampens the vibrations of the boiler body, thereby increasing the earthquake-proofing effect when the boiler is transported by sea.

It should be noted that the individual materials of the assembly members of the stored water resonance prevention device do not have to have a specific gravity that is lighter than water, as long as they float. For example, as shown in FIG. 5, a hollow unit member 13a is formed from a thin steel plate or the like. However, they can also be connected to each other by hooks 13b and receiving metal fittings to separate free water near the water surface.

As mentioned above, it is not uncommon for a boiler to resonate due to waves with a period of one to several seconds, which is about the same as the natural vibration period of the boiler, and the resonance magnification when resonance occurs depends on the damping constant ratio of the boiler. circle. Boilers with a mainly steel structure have a low damping constant ratio of 0.05 or less.
The resonance magnification with respect to the acceleration amplitude is about 10 times or more.

On the other hand, experimental results in which water was introduced into the furnace showed that
The resonance magnification is 3.3, and the damping constant ratio calculated backward from the resonance magnification is 0.15.
It has the effect of reducing the amount to less than one-fold.

FIG. 6 shows another embodiment of the present invention, in which the boiler body 14 is mounted on a support 1 on the double bottom 3.
5 is supported from below. The tank 16 is a heavy oil tank during plant operation, and can be used as a water tank during sea transportation. Water 12 for earthquake prevention is supplied to the boiler furnace by the water supply pump 7.
By supplying water and adjusting the depth of the water stored in the furnace, earthquake prevention effects can be achieved. Similarly, a water supply pipe 7a and a drainage pipe 7b are provided.

There is almost no additional equipment required for this embodiment, and the boiler water pump can be used as the pump. In addition, if necessary, inexpensive miscellaneous pumps and temporary piping can be used. As for the boiler itself, the furnace is made airtight, and a manhole or viewing window for inspecting the inside of the furnace can be used to supply water, and an outlet for draining fuel combustion residue can be used for drainage. can.

By implementing this invention, the strength of large transported objects and steel frames has been significantly increased compared to normal on-site assembly as a vibration countermeasure, but now it can be reduced to almost the same level as conventional domestic on-site assembly. It can be made suitable for transport by water. Therefore, there is no need for special design,
Material costs are also reduced, and standard products can be used during design, reducing design costs.
As assembly is carried out in a well-controlled factory, defects caused by work on site with inadequate equipment are eliminated, reliability of the equipment is improved, assembly costs are reduced, special inspection considerations are required for sea transport, and weather considerations are avoided. This has various effects such as reducing the number of earthquakes and making earthquake prevention work easier to manage.

[Brief explanation of the drawing]

Fig. 1 is a side view of a boiler installed on a ship or barge, Fig. 2 is a front view thereof, Fig. 3 is a longitudinal cross-sectional view of the boiler in which the present invention is implemented, and Fig. 4 is a diagram of a device for preventing resonance of stored water. A perspective view showing an example; Fig. 5 is a sectional view showing an example in which the member forming the stored water resonance prevention device is formed hollow from a thin steel plate; Fig. 6 is a perspective view showing an example in which an empty heavy oil tank is used as a water tank and a bottom FIG. 2 is a longitudinal sectional view showing a support type boiler in which the present invention is implemented. 1...boiler body, 2...barge (ship), 3...
... double bottom, 4 ... upper deck, 5 ... ballast tank, 6 ... furnace, 7 ... pump, 7a ... water supply pipe, 7b, 8a ... drainage pipe, 9 ... stay, 10...Steel frame, 11...Sling, 12...
Water, 13... Reservoir water resonance prevention device, 14... Boiler main body, 15... Support, 16... Heavy oil tank.

Claims (1)

[Claims] 1. A method for transporting large objects having an airtight space on a barge by storing water in the airtight space, floating a member having a specific gravity lighter than water on the upper surface of the stored water, and A method for transporting large objects by water, characterized in that the upper part of the stored water is divided by the member, and the natural vibration period of the stored water is changed to prevent resonance of the large objects. 2. In cases where large cargo is transported by water by attaching it to a barge and protecting it from earthquakes, there is a pipe line that connects a tank installed on the barge to a water storage section in an airtight space via a water supply pump, and a pipe line that returns the stored water to the tank. and a pipe line including a stop valve for stopping the water, and a stored water resonance prevention device for partitioning free water by a plurality of members having a specific gravity lighter than water is placed floating on the upper surface of the water storage portion. Water transportation equipment for transported goods.