JP2007076735A - Method for inspecting state of apparatus for reducing swing, and tension detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting whether an apparatus for reducing swing of a floating roof having a swing control plate is in a normally operable state. <P>SOLUTION: The method includes a tension calculating step for calculating the rising and falling state of the swing control plate 22 based on the elevating/lowering quantity of the floating roof 18, and calculating the tensions in wire-like bodies 24 and 26 based on the calculated rising and falling state of the swing control plate 22, a tension detecting step for detecting the tension exerted in the wire-like bodies connected to the edge of the floating roof 18, and a state determination step for deriving the errors in the tension by comparing the tension in the wire-like bodies 24 and 26 calculated by the tension calculation with the tension exerted in the wire-like bodies 24 and 26 detected by the tension detecting step, and for determination the state of the apparatus 10 for reducing swing by comparing the error with the predetermined threshold. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for inspecting a state of a floating roof rocking device for reducing the swing of a floating roof of a floating roof type tank storing oil or the like outdoors, and a tension detection device used in the state inspection method.

  Floating roof tanks are used for large tanks that store crude oil or naphtha outdoors. The floating roof type tank has a lid called floating roof floating on the surface of liquid such as crude oil stored in the tank body, and a sealant is placed between the floating roof and the tank body to prevent the crude oil from evaporating. It is preventing. The floating roof ascends and descends in the tank body as the liquid level varies with the increase or decrease of the liquid in the tank body. In this floating roof type tank, even if the liquid in the tank is reduced, crude oil, naphtha, etc. do not come into contact with the air, so that it is possible to avoid danger such as fire.

However, when an earthquake occurs and the tank is shaken, the floating roof is also shaken as the liquid in the tank is shaken. In particular, when a shake of several seconds to several tens of seconds is applied to the tank, the liquid surface greatly fluctuates in accordance with the natural period of the fluctuation of the liquid in the tank. For this reason, when a large amount of crude oil or the like is stored in the tank, the floating roof is greatly inclined due to large fluctuations in the liquid level, and crude oil or the like spills from the tank, or the floating roof is attached to the tank body. It crashes and breaks, or when it collides, a spark is generated and it becomes a fire. For this reason, various devices for preventing the swinging of the floating roof have been considered. For example, a plurality of water control plates that are folded up and down via hinges are arranged to partition the inside of the tank to reduce the hydraulic pressure generated in the tank. There are ones (Patent Document 1) that are made to suspend a wire on a floating roof, and a resistor made of a flat plate in the horizontal direction is attached to the wire (Patent Document 2).
JP-A-57-142892 JP-A-9-142575

Since the liquid level fluctuation preventing device for a tank described in Patent Document 1 reduces the amount of liquid that can be swung by partitioning the inside of the tank, it is expected that the fluctuation of the liquid level will be smaller than that in the prior art. . However, the thing of patent document 1 cannot fully suppress the rocking | fluctuation of a floating roof, since the edge part (edge part) of a floating roof is not restrained. In the tank described in Patent Document 2, the resistor is made of a flat plate in the horizontal direction, and the lower end of the wire is not fixed. Therefore, the resistor can prevent the liquid from swinging. The liquid level may swing greatly, and the floating roof may swing significantly. Furthermore, there is no possibility of inspecting whether or not the above-described swing prevention device is actually operable inside the tank after installation, and there is a possibility that the device will not operate when necessary.
The present invention is a state inspection method capable of easily inspecting whether or not the floating roof rocking device made to eliminate the drawbacks of the prior art is in a state in which it can normally operate inside the tank, And it aims at providing the tension | tensile_strength detection apparatus used for the said state inspection method.

  In order to eliminate the drawbacks of the prior art, the inventor of the floating roof developed by the inventor is provided with a rocking suppression plate provided at the bottom of a tank main body of a floating roof type tank for storing liquid, and one end thereof. A cable-like body connected to one side edge of the floating roof floated on the surface of the liquid and the other end connected to the rocking suppression plate, and the rocking body caused the rocking roof to swing The vibration is transmitted to the rocking suppression plate as tension, and the rocking suppression plate is undulated. The state inspection method according to the present invention, which makes it possible to inspect the state of the vibration reducing device having such a configuration and achieve the above-described object, is based on the amount of lifting of the floating roof. A tension calculating step for calculating the undulation state and calculating the tension of the cord-like body based on the calculated undulation state of the swing control plate, and a tension applied to the cord-like body having one end connected to the edge of the floating roof An error is derived by comparing the tension of the cord-like body calculated by the tension detecting step, the tension of the cord-like body calculated by the tension calculating step, and the tension of the cord-like body detected by the tension detecting step. And a state determination step of determining the state of the vibration reduction device by comparing with the threshold value.

  Further, in the state inspection method having the above-described characteristics, the tension detecting device according to the present invention as a device used to detect the tension of the cord-like body is provided at the bottom of the tank main body for storing the liquid so as to be freely raised and lowered. A floating roof vibration reduction device comprising: a rocking suppression plate, and a cord-like body having one end connected to an edge of the floating roof floating on the surface of the liquid and the other end connected to the rocking suppression plate. An apparatus for detecting the tension of the cable-shaped body provided, and a pedestal that receives the tension of the cable-shaped body, and an end of the cable-shaped body that penetrates the edge of the floating roof and the cradle. A closing member that is connected and closes a through hole that penetrates the cord-like body by being placed on the cradle; and a sensor means that detects a reaction force of the cradle that occurs when the closing member is supported. It is characterized by having.

In the tension detection device having such a configuration, the sensor means is a spring member, and the cradle includes a reaction force receiver and a pulling means for pulling up the closing member from the cradle via the reaction force receiver. Preferably, the spring member is interposed between the reaction force receiver and the lifting means, and the displacement of the spring member that occurs when the closing member is lifted from the cradle is measured.
In the tension detecting device having the above-described configuration, it is preferable that the closing member includes a gas injection port for injecting an inert gas into the through hole.

  In the method for inspecting the condition of the vibration reducing device as described above, since the tank capacity, the length of the rope body, the routing route of the rope body, etc. are known values, it is based on the lift amount of the floating roof that is a variable value By calculating the undulation state of the swing control plate, it is possible to calculate (estimate) how much tension is applied to the cord-like body connected to the swing control plate. On the other hand, by detecting the tension applied to one end of the cable connected to the edge of the floating roof and comparing this value with the calculated value, the actual undulation state of the swing control plate is calculated. You can know how much it deviates from the value. For this reason, unless there is a large difference between the calculated value that is the estimated tension and the detected value that is actually acting on the cord-like body, the swing control plate is in a state in which it can operate normally. Can be determined. Regarding the determination, it is sufficient to determine that the difference between the detected value and the calculated value is normal if the difference between the detected value and the calculated value is within a range by setting a threshold value in advance, taking into account the secular change in the length of the cord. .

Moreover, according to the tension detection apparatus having the above-described configuration, the tension applied to the cord-like body can be detected when the above method is performed. Moreover, since it has the structure which obstruct | occludes the through-hole which penetrates a cord-like body by mounting an obstruction | occlusion member in a cradle, it can prevent that the liquid stored inside the tank leaks or evaporates. .
Moreover, according to the sensor means being a spring member and measuring the displacement of the spring member to detect the tension of the cord-like body, the device configuration becomes simple and the displacement can be easily measured. .

  Further, by providing the closing member with an injection port for injecting an inert gas into the through hole, it becomes possible to inject the inert gas into the through hole. As a result, the liquid to be stored does not come into contact with air or the like. Moreover, generation | occurrence | production of the vaporization gas from a liquid can be suppressed, and even if vaporization gas is combustible, dangers, such as a fire, can be prevented.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to a state inspection method and a tension detection device of the present invention will be described with reference to the drawings.
First, with reference to FIG. 1, the schematic structure of the rocking | swiveling apparatus of the floating roof used as the object which implements the state inspection method of this invention is demonstrated.
In FIG. 1, the floating roof type tank 10 stores a liquid 14 such as crude oil inside a tank body 12. A floating roof 18 is floated on the liquid level of the liquid 14. In the floating roof type tank 10, a seal member 16 is disposed between the tank main body 12 and the floating roof 18 to prevent the liquid 14 stored in the tank main body 12 from evaporating. In addition, a vibration reducing device 20 for reducing the swing of the floating roof 18 is provided inside the tank body 12.

  The vibration reduction device 20 includes a rocking suppression plate 22, a first cord-like body 24, a second cord-like body 26, and pulleys 28 (28a, 28b), 30 (30a, 30b). The swing suppression plate 22 is attached to the bottom plate of the tank body 12 via a hinge 32 and can be raised and lowered in either the left or right direction as indicated by an arrow 34. In addition, you may be able to undulate freely only in any one. Further, it is desirable that the swing suppression plate 22 is attached in a state slightly lifted from the bottom plate so that the cable-like bodies 24 and 26 can pass through the lower portion. And the upper end of the rocking | fluctuation suppression board 22 is connected to the lower surface of the floating roof 18 via raising members 36, such as a wire rope. The pull-up member 36 injects the liquid 14 into the tank body 12 when the liquid 14 in the tank body 12 is pulled out and the floating roof 18 descends and the swing suppression plate 22 falls down. This is to cause the rocking suppression plate 22 by raising.

  The first cord-like body 24 and the second cord-like body 26 are formed from a bendable wire rope, a cord or the like. One end of the first cord-like body 24 is provided on the upper surface side of the floating body portion 38 that is an edge of one side (the other surface side of the rocking suppression plate 22) with respect to the rocking suppression plate 22 of the floating roof 18. The tension detecting device 100 is connected. The pulleys 28a and 28b constitute a first guide member, and the first cord-like body 24 is stretched over the pulleys 28a and 28b. The pulley 28a is attached to the lower part of the tank body 12 and almost directly below the tension detecting device 100 to which the first cord-like body 24 is connected. The pulley 28b is attached to a position corresponding to the pulley 28a on the opposite side of the swing suppression plate 22, that is, the lower portion of the tank body 12 facing one surface of the swing suppression plate 22. The first cord-like body 24 is hung on the pulley 28a at an intermediate portion, passed under the swing suppression plate 22 and hung on the pulley 28b. The other end of the first cord-like body 24 is connected to the upper part of the swing suppression plate 22.

  One end of the second cord-like body 26 is provided on the upper surface side of the floating body portion 38 that is an edge of the other side (one surface side of the rocking suppression plate 22) with respect to the rocking suppression plate 22 of the floating roof 18. Connected to the tension detector. The second cord-like body 26 is guided to one side with respect to the rocking suppression plate 22 via pulleys 30a and 30b whose intermediate portion constitutes the second guide member, and the tip thereof is the rocking suppression plate 22. Connected to the top of That is, the second cord-like body 26 is stretched over a pulley 30a provided below the tension detecting device 100 whose one end is connected to one end, passed under the swing suppression plate 22 and provided on the opposite side. 30b.

  Next, a first embodiment according to the tension detection device of the present invention will be described with reference to FIG. The tension detecting device 100 includes a cradle 110 provided with a through hole 110a for guiding the cord-like bodies 24, 26 to the upper surface of the floating body portion 38, and a closing member 112 to which one ends of the cord-like bodies 24, 26 are connected. And have.

  As described above, the closing member 112 is a plate member to which one ends of the cords 24 and 26 are connected, and is placed on the cradle 110 as shown in FIG. 2 except when the tension is detected. In order to guide the cords 24 and 26 to the upper surface of the floating roof 18, the through holes 38 a and 110 a provided in the floating body portion 38 and the cradle 110 are closed. Further, a screw hole 112a provided with a screw groove is formed on the upper surface of the closing member 112, and has a structure that can be screwed with a lifting means 114 described later. Further, in the closing member 112 shown in the present embodiment, a hole for providing a detent 122 for preventing the closing member 112 itself from rotating by screwing with the lifting means 114, the floating body portion 38 and the receiving member. A through hole for injecting an inert gas such as nitrogen gas into the through holes 38a, 110a provided in the base 110, and an inert gas inlet 113 provided in the through hole are provided. .

  The cradle 110 is a plate member capable of receiving tension acting on the cords 24 and 26, and is preferably formed so that the upper surface thereof is horizontal. In addition, a plurality of support columns 116 are erected on the cradle 110, and a plate member serving as a reaction force receiver 118 is provided at an intermediate portion of the support columns 116. A through hole 118 a is formed in the reaction force receiver 118, and the through hole 118 a is provided with a lifting means 114 having a screw portion that is screwed into the screw hole 112 a of the closing member 112.

The lifting means 114 is a rod-like member, and has a so-called bolt shape having a threaded portion at one end and an extended portion at the other end. The through-hole 118 a provided in the reaction force receiver 118 can be inserted only at one end side of the lifting means 114, and the other end side has a hook between the reaction force receiver 118.
Further, a spring member 120 is interposed between the other end side of the lifting means 114 and the reaction force receiver 118, and a reaction force generated when the closing member 112 is pulled up is visually observed as a displacement of the spring member 120. The configuration is such that it can be performed.

  In the tension detecting device 100 having such a configuration, by rotating the other end side of the lifting means 114, one end side of the lifting means 114 and the screw hole 112 a of the closing member 112 are screwed together and rotated by the rotation stop 122. The blocking member 112 that has been prevented is pulled up from the cradle 110 in the vertical direction (see FIG. 3).

  When the closing member 112 is pulled up, the spring member 120 sandwiched between the reaction force receiver 118 and the other end of the lifting means 114 is displaced in the contracting direction. Since the amount of displacement of the spring member 120 is proportional to the increase or decrease of the tension of the cord-like bodies 24, 26 connected to the closing member 112, it acts on the cord-like bodies 24, 26 based on the amount of displacement of the spring member 120. The tension can be detected.

  According to the tension detection device 100 having such a configuration, since the device configuration is simple and the displacement of the spring member 120 can be visually confirmed, the tension acting on the cords 24 and 26 can be easily detected. It becomes possible to do. Further, since the inert gas injection port 113 is provided in the closing member 112 and the inert gas is injected into the through holes 38 a and 110 a provided in the floating body 38 and the cradle 110, it is stored in the tank body 12. As a result, the liquid does not come into contact with air, and safety can be ensured.

Next, a second embodiment according to the tension detection device of the present invention will be described with reference to FIG. The basic configuration of the tension detection apparatus of the present embodiment is the same as that of the tension detection apparatus shown in the first embodiment. Accordingly, parts having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.
The difference from the tension detecting device shown in the first embodiment is that the spring member 120 provided as the sensor means is eliminated and the strain gauge 130 is attached to the lifting means 114.

  In the tension detection device 100 having such a configuration, when the lifting member 114 is rotated to lift the closing member 112 from the cradle 110, the lifting member 114 itself is distorted. In the tension detector 110 of this embodiment, the strain acting on the cords 24 and 26 is detected by directly measuring the strain (extension) generated in the lifting means 114. In the tension detection device of the present embodiment, the strain gauge 130 may be attached to the column 116 that supports the reaction force receiver 118 and the like, and the strain (shrinkage) of the column 116 may be measured. Thus, in the tension detection apparatus of the present invention, various displacement meters can be used as the sensor means.

  When the vibration reduction device 20 described above is in an operable state, the vibration reduction device 20 has the following effects and can obtain a high vibration reduction effect. Now, as shown in FIG. 5, when the earthquake acceleration 50 acts in the left direction in the figure, the tank body 12 receives a force that moves in the left direction, and the liquid 14 in the tank body 12 moves substantially to the right. The same effect as described above is produced, and the tank body 12 is pressed against the right inner surface. For this reason, the pressure of the right side portion in the tank body 12 is increased and the liquid level is increased, and the pressure of the left side portion is decreased and the liquid level is decreased. Therefore, the rotational moment 54 acts on the floating roof 18 as shown by the arrows, and the right side rises and the left side falls as the liquid level changes.

  When the right side of the floating roof 18 rises, the second rope 26 connected to this portion is pulled, and a large tension 52 is applied to the second rope 26. On the other hand, the left side of the floating roof 18 is lowered as the liquid level is lowered, and the tension of the first cord-like body 24 connected to this portion is reduced. And the big tension 52 which arose in the 2nd cord-like body 26 is transmitted to the other end side of the 2nd cord-like body 26, the upper end of the rocking | fluctuation suppression board 22 is pulled in the left direction of FIG. 22 is rotated counterclockwise to prevent the liquid 14 existing on the left side of the rocking suppression plate 22 from moving in the right direction. For this reason, the rotational moment 54 which tries to rotate the floating roof 18 counterclockwise becomes small, and the swing of the floating roof 18 can be suppressed.

  As shown in FIG. 6, when the floating roof 18 rotates in the direction of the arrow 56 and the swing suppression plate 22 rotates counterclockwise, the liquid 14 on the left side of the swing suppression plate 22 A large pressure is applied to the left side of the plate, and a part thereof moves over the swing suppression plate 22 to the right side of the swing suppression plate 22. For this reason, in the tank body 12, the pressure on the left side of the rocking suppression plate 22 increases and the pressure on the right side decreases. Therefore, as shown by the arrow 58, the rocking suppression plate 22 receives a force pushed in the right direction and gives a large tension to the second cord-like body 26. For this reason, the large tension acting on the second cable-shaped body 26 pulls the right side portion of the floating roof 18 connected to the second cable-shaped body 26 downward, and a large reaction force moment 60 indicated by an arrow is applied to the floating roof 18. give. Therefore, the swinging of the floating roof 18 is suppressed, and a large rocking effect can be obtained. The same applies when the earthquake acceleration acts in the opposite direction.

The state inspection method of the vibration reduction device for inspecting whether or not the vibration reduction device 20 described above is in a state in which the above-described operation can be performed is as follows.
First, the capacity of the tank body 12, the amount of lifting of the floating roof 18, the lengths of the ropes 24 and 26, the routing path of the ropes 24 and 26, and the connection of the ropes 24 and 26 to the swing control plate 22 The undulation state (tilt angle) of the swing control plate 22 in the tank body 12 is calculated (estimated) in consideration of the position and the secular change in the length of the cords 24 and 26 (FIG. 7: S100). . Next, the tension acting on the cords 24 and 26 is calculated in consideration of the calculated tilt angle of the swing control plate 22, the shape of the swing control plate 22, the specific gravity of the stored liquid, and the like (S110). ).

Apart from the calculation of the tension acting on the cords 24 and 26, the tension detector 100 is used to pull up one end of the cords 24 and 26 and actually act on the cords 24 and 26. The tension is detected (S130).
The tensions of the cords 24 and 26 calculated as described above are compared with the measured tensions of the cords 24 and 26, and an error of the actually measured value with respect to the calculated value is obtained (S140).

  Here, when there is no large error between the actually measured value and the calculated value, it can be determined that the vibration reducing device 20 is in a state where it can operate normally. That is, when a large error occurs between the actually measured value and the calculated value, an abnormality has occurred in the cord-like bodies 24, 26, the swing control plate 22, etc., and the vibration reducing device 20 is operating normally. It can be determined that there is a possibility of not operating. To determine whether the vibration reduction device 20 is in a normal state or whether the vibration reduction device 20 is abnormal, a threshold is set for the error between the calculated value and the actual measurement value relating to the tension of the cords 24 and 26. When the threshold value is exceeded, it is determined as “abnormal”, and when the error is within the threshold value, it is determined as “normal”. Note that the threshold value may be set each time from the measurer's empirical rule based on various factors such as the above-mentioned change in the length of the rope (S150).

  According to the shaker inspection method as described above, it is possible to easily determine whether or not the shaker 20 having the above configuration is a normally operable state. If it is understood that an abnormality has occurred in the vibration reduction device 20, the vibration reduction device can be repaired before a disaster such as an earthquake occurs. Furthermore, it is possible to avoid a situation in which the floating roof is lowered without the swing control plate being tilted and the swing control plate is in contact with the floating roof.

It is explanatory drawing of the rocking | swiveling apparatus of a floating roof provided with the tension | tensile_strength detection apparatus which concerns on this invention. It is a figure which shows the state in the normal time of 1st Embodiment which concerns on the tension | tensile_strength detection apparatus of this invention. It is a figure which shows the state at the time of tension detection of 1st Embodiment which concerns on the tension | tensile_strength detection apparatus of this invention. It is a figure which shows 2nd Embodiment which concerns on the tension | tensile_strength detection apparatus of this invention. It is explanatory drawing of the rotational moment which acts on a floating roof when a vibration reduction apparatus operates. It is explanatory drawing of the reaction force moment which acts on a floating roof when a vibration reduction apparatus operates. It is a flow of the state inspection method of the vibration reduction device of the present invention.

Explanation of symbols

  10 ......... Floating roof type tank, 12 ......... Tank body, 18 ......... Floating roof, 20 ......... Attenuator, 22 ......... Oscillation restraint plate, 24 ......... First cord-like body, 26 ......... Second cord-like body, 28a, 28b ......... First guide member (pulley), 30a, 30b ...... Second guide member (pulley), 36 ......... Elevating member, 100 ......... Tension detecting device 110... Cradle 112... Closing member 114... Lifting means 116... Strut 118.

Claims (4)

A swing suppression plate provided at the bottom of the tank main body of the floating roof type tank for storing liquid, and one end connected to one side edge of the floating roof floating on the surface of the liquid, and the other end of the swing roof type tank. A floating body connected to the movement restraining plate, and transmitting the swing of the floating roof to the swing restraining plate as a tension generated in the rope, so that the swing restraining plate is undulated. A roof anti-vibration device,
A tension calculation step of calculating the undulation state of the swing control plate based on the lift amount of the floating roof, and calculating the tension of the cord-like body based on the calculated undulation state of the swing control plate;
A tension detecting step for detecting the tension applied to the cable-shaped body having one end connected to the edge of the floating roof;
An error is derived by comparing the tension of the cable body calculated by the tension calculation step with the tension of the cable body detected by the tension detection step, and the error is compared with a predetermined threshold value and reduced. A state determination step for determining the state of the rocking device;
A method for inspecting a state of a vibration reducing device, comprising: A rocking restraint plate provided at the bottom of the tank main body for storing the liquid, and one end connected to the edge of the floating roof floating on the surface of the liquid and the other end connected to the rocking restraint plate A device for detecting the tension of the cord-like body provided in the rocking device of the floating roof,
A cradle for receiving the tension of the cord;
A closing member that is connected to one end of the cable-like body that penetrates the edge of the floating roof and the cradle, and closes a through-hole that penetrates the cable-like body by being placed on the cradle;
Sensor means for detecting a reaction force of the cradle generated when supporting the blocking member;
A tension detecting device comprising: The sensor means is a spring member,
The cradle includes a reaction force receiver,
A lifting means for lifting the closing member from the cradle via the reaction force receiver,
3. The displacement of the spring member generated when the closing member is lifted from the cradle is measured by interposing the spring member between the reaction force receiver and the lifting means. The tension detection device described.   The tension detecting device according to claim 2, wherein the closing member is provided with a gas injection port for injecting an inert gas into the through hole.

Images