JPS5847816A - Regulator for axial force - Google Patents

Abstract

PURPOSE:To prevent the occurrence of out-of-plane movement of a work platform against tidal wave as well as make uniform pressure to legs at the ebb and flow by a method in which orifice is provided between a cylinder and a working liquid container and the size of a pressure gas container is made sufficiently larger than that of the working liquid container. CONSTITUTION:A piston 13 is povided to the leg 12 of a base ship 11, a cylinder 14 is fixed to the work platform 11, and the cylinder 14 is connected to a working liquid container 15 with a working liquid 20 through a communication tube 17 and an orifice 19. The working liquid container 15 is led to a pressure gas container 16 with a pressure gas 21 through a communication tube 18. Since the volume of the pressure gas container is made sufficiently larger than that of the working liquid container 15, no change in the pressure of the pressure gas 21 with change in long-period water level of tidal wave occurs and therefore, constant axial force is always applied to the leg 12. With changes in the short-period water level of tidal wave, the orifice 19 becomes nearly closed, and therefore, no displacement occurs in the piston 13 and the cylinder 14 and also no out of plane movement of the platform 11 takes place.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an axial force adjustment device for a leg of a semi-jerker-up barge or a mooring leg of a tension-moored floating body.

As shown in FIG. 1, in general, a semi-jerker-up type barge 1 has a footing 4 at the lower end of a pedestal 2 pressed against the seabed, and a jack-up device 3 jacks the barge 1 up to a position slightly above the free-floating, swamping state. However, if the still water surface (the water surface when there are no waves or the average water surface when there are waves)
When the wave 6 breaks, a peak of the wave appears near one of the pillars 2, and even if the buoyant force in that area cools, a compressive force remains that maintains the axial force of the pillar 2, and during the waves. Even so, there is no out-of-plane displacement around the barge, that is, rolling, pitching, heaving, and various operations can be performed on the barge surface without shaking.

In addition, the tension mooring type floating body 7 shown in FIG. , and if there are waves on the still water surface 6 and a wave trough appears near one of the legs, and the buoyancy in that area decreases, the mooring legs 8 A certain amount of axial tension remains, so that there is no periodic displacement of the floating body 7 even in waves, and various operations can be performed on the floating body without shaking.

Based on the above idea, the compressive axial force of the leg of a half-jerker-up type barge or the tension axial force of the mooring leg of a tension-moored floating body is determined in advance by the maximum amount of buoyancy fluctuation due to waves during operation, and the water level difference expression. Then, it is sufficient to give a value corresponding to the wave height of approximately H'<.

In other words, in the case of a semi-jerker-up type barge, the leveling effect caused by the barge riding on multiple waves and the countervailing fluid force acting on the bottom of the ship, and the tension mooring type floating body. In this case, due to the countervailing fluid force acting on the lower surface of the supporting floating body and the lower hull, the value is considerably reduced to an order of magnitude more than the above value.

Considering this, the maximum value of the axial force occurs when the bottom of the wave comes near the legs in the case of a half-jerker-up type barge.
Its value is on the order of wave height V2 in water level difference expression (
(See Figure 3 (5)).

In addition, in the case of a tension-moored floating body, this occurs when a wave crest comes near the legs, and its value is on the order of the wave height V2 when expressed as a water level difference (see Figure 4 (a)).

The above is for installation at a location where there are no long-term water level fluctuations such as ebb and flow of tides, high tides when low pressure passes, and water level rise due to tsunamis when offshore earthquakes occur. If possible, (for example, on the coast of Japan, it is necessary to assume that the difference between the high and low tide levels is about 5 m)
In the case of a half-jerker-up type barge, even when a wave crest comes near a certain leg at a high water level during long-term water level fluctuations, the axial compressive force of the leg remains, causing the footing to leave the seabed and the barge to rise flat. If we want to prevent external movement, at the low water level of long-period water level fluctuations, only the amount of buoyancy per leg of the barge that corresponds to the water level difference of long-period water level fluctuations is It is superimposed on FIG. 0 and becomes as shown in FIG. 3.

In the case of a tension platform-type floating body, even when the bottom of a wave comes near a certain leg at low water levels during long-term water level fluctuations, the axial tension of the leg remains, causing the mooring leg to sag and the barge to go out of plane. If we want to avoid shaking, at the high water level of long-period water level fluctuations, only the buoyancy fluctuation per leg of the barge corresponding to the water level difference of long-period water level fluctuations is shown in Figure 4 (G). Superimpose the image in Figure 4 (
It becomes like Q.

In other words, whether it is a semi-jerker-up type barge or a tension-moored type floating body, when these are installed in sea areas where there is no long-term water level fluctuation, or even if there is, it is relatively small, a wave height of 10''' is measured on the axial force scale of the leg. This corresponds to a hiccup difference of the order of 2.57″ on average and 5″′ at maximum.

On the other hand, when these are installed in sea areas where there are long-term water level fluctuations, the axial force of the legs is, for example, the 5 m tidal difference that is expected in the Japanese sea area, and the wave height is 10 r.
When assuming 11 waves, the average Te5″I+2.5WL
= 7.5rr'・Old...(1) Maximum Te5"+5"=
10rn, --- This is comparable to the stuttering difference in (2), and compared to the former, the axial force is three times the average value and twice the maximum value.

Therefore, when planning a semi-jacketed barge or a tension-moored floating body that operates in sea areas with long-term water level fluctuations such as those mentioned above, it is necessary to The pressure-receiving area, the cross-sectional area of the tension mooring legs, and the weight of the anchor are on the order of three times the average value and twice the maximum value than the ground bearing capacity, which increases the device manufacturing cost and installation cost. In addition, especially in the case of semi-jerker-up type barges, the out-of-plane load (gravity minus buoyancy) distribution and column axial force of the barge are large at low water levels, and the structural dimensions to accommodate out-of-plane shearing and shearing of the barge are large. increases.

Incidentally, if a constant tension device such as a constant tensioner, a very long metal spring, or an air spring is used to connect the upper end of the leg to the barge or floating body, axial force fluctuations due to long-period water level fluctuations can be avoided, but at the same time The object of the present invention, which is to eliminate out-of-plane fluctuations caused by vertical waves of the barge or floating body in order to cope with buoyancy fluctuations, cannot be achieved.

The present invention prevents the occurrence of axial force fluctuations due to long-period water level fluctuations, and preserves the axial force fluctuations due to short-period water level fluctuations, thereby achieving the characteristic of preventing out-of-plane motion in waves, which is the purpose of these structures. The object of the present invention is to make it possible to provide a semi-jack-up type barge or a tension moored type floating body that is lightweight and easy to install while preserving the same characteristics, and is therefore inexpensive.

That is, one of the axial force adjusting devices of the present invention is to provide a piston portion of a fluid cylinder in a leg portion of a semi-jacketed barge or a mooring leg of a tension moored type floating body, and to provide a piston portion of a fluid cylinder in a leg portion of a semi-jacketed barge or a mooring leg of a tension moored type floating body. The cylinder part of the fluid cylinder is completely fixed, and a hydraulic fluid storage container for storing the hydraulic fluid of the fluid cylinder is communicated with the fluid cylinder through a communication pipe, and an orifice or choke valve or the like with large fluid passage resistance is connected to the communication pipe. The present invention is characterized in that it includes a controller and a pressure urging device that applies high pressure to the hydraulic fluid in the hydraulic fluid storage container.

The other method is to provide a piston portion of a fluid cylinder in a leg portion of a semi-jacketed barge or a mooring leg of a tension-moored floating body, and to attach a cylinder portion of a fluid cylinder to the barge or floating body. A hydraulic fluid storage container that is fixed and stores the hydraulic fluid of the fluid cylinder is connected to the liquid cylinder through a communication pipe, and a piston device is provided in the hydraulic fluid storage container that operates according to pressure fluctuations of the hydraulic fluid. It is characterized by:

Furthermore, another method is to provide a piston portion of a fluid cylinder in a leg portion of a semi-jacketed barge or a mooring leg of a tension-moored floating body, and to install a piston portion of a fluid cylinder in the barge or floating body. A hydraulic fluid storage container for storing the hydraulic fluid of the fluid cylinder is connected to the fluid cylinder through a communication pipe, and the communication pipe is provided with a pump and an on-off valve that operate according to fluctuations in the hydraulic fluid. It is characterized by

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

Figures 5 and 6 show an example in which the axial force adjustment device of the present invention is applied to a semi-jack barge.
The relative positional relationship of each device is shown when the long-period water level is at its highest level, and FIG. 6 shows the relative positional relationship of each device when the long-period water level is at its lowest level, such as during low tide.

In FIGS. 5 and 6, the barge 11 is lifted up by the pillars 12 somewhat above the free floating state, but the barge 11
A piston 13 provided at the tip of the pillar 12 to lock the piston 13
is fitted into a cylinder 14 fixed to the barge 11, and is held in position by high pressure hydraulic fluid 20 within the cylinder 14. Practically speaking, a barge requires pre-length in its pedestal in order to be usable regardless of the depth of the water, but in order to help understand the device of the present invention, we will explain the case where a piston is provided at the top end of the pedestal. shall be taken as a thing.

Further, the barge 11 is equipped with a hydraulic fluid storage container 15 and a pressurized gas storage container 16. The top of the cylinder 14 and the bottom of the hydraulic fluid storage container 15 communicate with each other through a communication pipe 17, and the communication pipe 17 is provided with a flow controller 19 such as an orifice with large passage resistance or a choke valve. This flow controller 19 is set in a state close to blockage so that the hydraulic fluid flows only in response to long-period water level fluctuations such as the ebb and flow of the tide. Further, the hydraulic fluid storage container 15 and the pressurized gas storage container 16 communicate with each other through a connecting pipe 18. The volume of the hydraulic fluid storage container 15 is approximately the same as that of the cylinder 14, and the volume of the pressurized gas storage container 16 is sufficiently large for the hydraulic fluid storage container 15.

Therefore, the gas volume in the pressurized gas storage container 16 is
Even if the state at high tide shown in the figure changes to the state at low tide shown in FIG. Virtually nothing has changed. This pressure is applied to the cylinder 14 and the hydraulic fluid storage container 1.
This is the average pressure of the hydraulic fluid 20 in the column 5, and a set average axial force can always be applied to the pillar regardless of long-term water level fluctuations such as ebb and flow of the tide. On the other hand, pressure fluctuations occur in response to short-period water level fluctuations caused by waves, but the flow controller 19
Since the piston 13 and the cylinder 14 are constricted to a state close to being closed, the relative positions of the piston 13 and the cylinder 14 do not change. In other words, no out-of-plane movement of the barge 11 occurs.

As the tide level gradually decreases from the high tide state shown in FIG.
Since the hydraulic fluid 20 in the cylinder 14 is added to the pressurized gas 2
It passes through the flow controller 19 against the pressure of 1 and gradually returns to the working fluid storage container 15, and at low tide it becomes as shown in FIG.

On the contrary, when the tide level gradually increases from the low tide state shown in FIG. 19 and gradually flows into the cylinder 14, and at high tide it reaches the state shown in FIG.

FIG. 7 shows an example suitable for practical use, and the same members as in the examples of FIGS. 5 and 6 are given the same reference numerals. The biggest difference from the examples shown in FIGS. 5 and 6 is that the pillar 12 passes through the cylinder 14, and the piston 13 is located in the middle of the pillar 12.
This is because we have established the following. That is, in the example shown in FIG. 7, since the pedestal 12 has a pre-length, it can be used both in shallow and deep water. Reference numeral 22 denotes a reserve tank that communicates with the cylinder 14 through a pipe 24 having an on-off valve 23, and is used to supply the hydraulic fluid 20 in the tank 22 into the cylinder 14, or to return the hydraulic fluid 20 in the cylinder 14 to the tank 22. By adjusting the position of the barge 11 according to the water depth,
can be installed.

FIGS. 8 and 9 show examples in which the axial force adjustment device of the present invention is used as a tensioning device for a tension mooring type floating body d mooring leg.
The figure shows the state when the water level is high for a long period such as at high tide, and FIG. be done. There is no possibility that the mooring legs 28 can be used in shallow or deep water by adjusting them in advance according to the water depth. Further, the provision of a hydraulic fluid storage container 15, a pressurized gas storage device 16, communication pipes 17, 18, and a flow controller 19 is exactly the same as the example shown in FIG.

However, in this example, due to the buoyancy of the floating body 27, the mooring leg 2
8 is tensioned, the communication pipe 1 is equipped with a flow controller 19.
The bottom of the 7Fi cylinder 14 and the bottom of the hydraulic fluid storage container 15 are communicated with each other.

However, at high tide, as shown in Figure 8, the mooring legs 2
In addition to responding to the ebb and flow of the tide by pulling up the mooring leg 28 at low tide, as shown in Figure 9,
Short-period water levels caused by waves are also dealt with in the same way as the examples shown in FIGS. 5 and 6.

The above is a purely mechanical device configuration, but it detects the transition of the average value (smooth value) of the pressure fluctuation of the hydraulic fluid, and adjusts the flow rate to keep the average pressure of the hydraulic fluid constant. You can also achieve your goals by controlling the process. FIGS. 10 and 11 show examples thereof. 1st
Figure 0 shows the application to a compression axial force adjustment device for the O-pillar of a semi-jerker-up type barge, and Figure 11 shows the application to a tension axial force adjustment device for the mooring leg of a tension-moored floating body. The case where is high is shown.

In addition, the device shown in Figure 10 can be used as a tension mooring type floating body.
There is no evidence that the device shown in the figure can be used on a semi-jacketed barge.

That is, in the example shown in FIG.
The electrical signal of the pressure change of the hydraulic pressure gauge 36 is converted into an average pressure signal by the smoothing circuit 37,
9 to open/close, and the pump 38 to start/stop.
and is transmitted to pump 38. As the valve 39 opens and closes and the pump 38 starts and stops, hydraulic fluid is sent and received through the high-pressure liquid pipe 35 communicating with the general high-pressure liquid container in the barge j1, and thus the hydraulic fluid in the piston 14 is Maintain average pressure.

On the other hand, in the example shown in FIG.
The pinion 4 is attached to the rack 43 provided on the rod 42 of the ton 41.
4 are engaged, and a hydraulic motor (not shown) that drives this pinion 44 is controlled by a start/stop signal issued from a smoothing circuit 37. Note that the internal pressure of the communication pipe 17 is detected by the hydraulic pressure gauge 36, and the electrical signal of this pressure change is sent to the smoothing circuit 37, as in the case of the example shown in FIG.

As described above, the present invention provides a piston portion of a fluid cylinder on a leg of a semi-jerker-up type barge or a mooring leg of a tension-moored floating body, and also provides a piston portion of a fluid cylinder on the barge, floating body, etc. A hydraulic fluid storage container for storing the hydraulic fluid of the fluid cylinder is connected to the fluid cylinder through a communication pipe, and the communication pipe is provided with a flow controller such as an orifice or choke valve with a large fluid passage resistance, In addition, since a pressure biasing device is provided that applies high pressure to the hydraulic fluid in the hydraulic fluid storage container, the semi-jacketed barge or the tension moored floating body can be kept out of plane against short-period water level fluctuations such as waves. Not only do they not oscillate, but they also move up and down in response to long-period water levels such as tides, which have large water level differences that cannot be ignored compared to waves. The strength of these members is about V2 to about that of the conventional method.

Therefore, construction costs and installation costs are significantly reduced.

Furthermore, instead of providing an orifice with large fluid passage resistance or a flow controller such as a choke valve in the communication pipe, a piston device that operates according to pressure fluctuations of the hydraulic fluid may be provided in the hydraulic fluid storage container, or A similar effect can be obtained by providing a pump and an on-off valve that operate according to fluctuations in the hydraulic fluid.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a half-judge-up type barge, Fig. 2 is a schematic diagram of a tension-moored floating body, and Fig. 3 is an explanation showing temporal fluctuations in compressive axial force in the legs of a conventional semi-judge-up type barge. figure,
Fig. 4 is an explanatory diagram showing temporal fluctuations in the tensile axial force of the mooring legs of a conventional tension-moored floating body, and Figs. 5, 6, and 7 show the application of the device of the present invention to a semi-jerker-up barge. FIGS. 8 and 9 are longitudinal sectional views showing the case where the device of the present invention is applied to a tension-moored floating body, and FIGS. 10 and 11 are longitudinal sectional views showing other embodiments of the present invention. A vertical cross-sectional view showing the . 11... Half jack up barge, 12... Legs, 1
3...Piston, 14...Cylinder, 15...Working fluid storage container, 17...Communication pipe, 19...Flow controller, 27・↓・Tension mooring type floating body, 28...Mooring leg. Agent: Patent Attorney Shin Ogawa − Patent Attorney Ken Noguchi Teru Patent Attorney Kazuhiko Saishita Figure 1 Figure 3 @ Figure 2 Figure 3 (A) Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. A piston portion of a fluid cylinder is provided in a leg of a semi-jerker-up barge or a mooring leg of a tension-moored floating body, and the cylinder of the fluid cylinder is provided on the barge, floating body, etc. A hydraulic fluid storage container for storing the hydraulic fluid of the fluid cylinder is connected to the liquid cylinder through a communication pipe, and the communication pipe is provided with a flow controller such as an orifice or a choke valve having a large fluid passage resistance. An axial force adjustment device characterized in that, f, a pressure urging device is provided for applying high pressure to the hydraulic fluid in the hydraulic fluid storage container. 2. The axial force adjustment device according to claim 1, wherein the pressure urging device is a pressurized gas storage container that stores pressurized gas. 3. Providing a piston portion of a fluid cylinder on a leg of a semi-jack-ag type barge or a mooring leg of a tension-moored floating body, and fixing the cylinder portion of the fluid cylinder to the barge, floating body, etc.; A hydraulic fluid storage container that stores the hydraulic fluid of the fluid cylinder and the fluid cylinder are connected through a communication pipe, and a piston device that operates according to pressure fluctuations of the hydraulic fluid is provided in the hydraulic fluid storage container. Characteristic axial force adjustment device. 4. A piston portion of a fluid cylinder is provided on a leg portion of a half-jerker-up type barge or a mooring leg of a tension-moored type floating body, and the cylinder portion of the fluid cylinder is fixed to the barge or floating body, etc. A hydraulic fluid storage container for storing the hydraulic fluid of the cylinder is connected to the fluid cylinder through a communication pipe, and the communication pipe is provided with a pump and an on-off valve that operate according to fluctuations in the hydraulic fluid. Axial force adjustment device.