JP3062476B2 - Tank accessory handling method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for handling accessories, such as a float of a liquid level gauge, in a hazardous material storage tank for storing flammable gas and toxic gas.

[0002]

2. Description of the Related Art In a storage tank storing dangerous substances such as liquefied natural gas (LNG), when repairing or replacing accessories present inside the tank, work is required to prevent the contents of the tank from leaking outside. There is a need to do.

[0003] For this reason, with regard to accessories such as a float of a liquid level gauge which is relatively frequently repaired or replaced, a special tank is used so that the accessories can be taken out while the dangerous goods are stored in the storage tank. Some have an accessory handling device.

[0004] As a conventional tank accessory handling apparatus, for example, there is one as shown in Japanese Patent Publication No. 1-23392. In the handling device described in this publication, a nozzle (tubular body) for handling accessories provided on the tank roof is surrounded by a glove box-type airtight box, and when the accessories are taken out from the nozzle, the contents of the tank are exposed to the outside. It is configured so as not to leak. When replacing tank accessories using this handling device, first make sure that the airtight box is completely closed, then remove the nozzle closing plate through the gloves of the airtight box and remove the accessories from the nozzle. Take out inside. Then
After closing the nozzle closing plate and purging the gas in the airtight box, open the airtight box and replace the accessories. Thereafter, the airtight box is closed, the nozzle closing plate is removed and accessories are returned to the inside of the tank, then the nozzle is closed, and finally the gas in the airtight box is purged.

[0005]

In the conventional apparatus and method for handling tank accessories described above, the nozzle is sealed only with the closing plate when the accessories are taken out of the airtight box. Since this sealing work is performed through gloves of an airtight box, it takes time and effort, but there is no problem such as leakage of tank contents as long as the closing plate is securely attached to the nozzle opening.

[0006] However, there is a need for a tank accessory handling method and apparatus that allows handling such as replacement and repair of tank accessories with a higher level of safety than at present.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to meet the above demands. The invention according to claim 1 is
In a storage tank in which a cylindrical body for handling accessories is provided on the tank roof or the side wall of the tank, this is a tank accessory handling method for taking out accessories through the tubular body to handle accessories inside the tank. A first sealing member for hermetically sealing the internal passage of the cylindrical body, and
Connecting a hermetic box containing a second seal member for hermetically sealing the opening of the cylindrical body and capable of being internally operated from the outside to the opening of the cylindrical body, Removing the closing plate at the opening of the tubular body, storing the accessory in the tubular body, and internal passage of the tubular body by the first seal member so that the accessory is isolated from the inside of the storage tank. And hermetically sealing the opening of the tubular body with the second sealing member after the accessory is moved to the hermetic box, and opening the hermetic box to expose the accessory to the outside. And a removing step. In this method, since the sealing of the cylindrical body is performed at two places, the safety is further improved.

The invention according to claim 2 is a tank accessory handling device which is particularly effective for carrying out the above tank accessory handling method, wherein the tank accessory handling device is airtightly connected to an opening of a cylindrical body. An airtight box capable of performing internal operations from the outside, a first sealing member housed in the airtight box, for hermetically sealing the internal passage of the tubular body, and housed in the airtight box. And a second sealing member for hermetically sealing the opening of the cylindrical body.

The first and second seal members are of a balloon type or a two-piece type so that they can be compactly stored in an airtight box and can be easily taken in and out of the cylindrical body.
A deformable type such as a folding type is preferable.

It is preferable that an airtight box is connected to the adapter tube after attaching the adapter tube to the cylindrical body so as to be applicable to various cylindrical bodies.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

The embodiment shown in FIGS. 1 to 3 is an example of an application of the present invention, in which a float type liquid level gauge 12 provided in a double shell type storage tank 10 for storing liquefied natural gas (LNG). 14 is to be replaced. As shown in FIG. 1, the liquid level gauge 12 measures the position of the float 14 floating on the liquid surface of LNG via a wire 18 that penetrates the tank roof 16 and is connected to the float 14. The float 14 is guided by a guide wire 22 extending vertically from the tank roof 16 to the tank bottom plate 20. A nozzle (cylindrical body) 24 penetrates and is attached to the tank roof 16, and the wire 18 and the guide wire 22 penetrate an airtight sealing plate 26 at the upper end of the nozzle 24 and hang down. The outer diameter of the float 14 is smaller than the inner diameter of the nozzle 24, so that the float 14 can be collected inside the nozzle 24 by pulling up the wire 18. A manhole (opening) 28 is formed on the side surface of the nozzle 24, and the float 14 collected in the nozzle 24 can be taken out through the manhole 28. Of course, when LNG is stored in the storage tank 10, the manhole 28 is airtightly closed by the closing plate 30.

In FIG. 1, reference numeral 32 denotes a seal plate, which is connected to the lower end of the guide wire 22. The seal plate 32 is for closing the lower end of the nozzle 24, but also functions as a weight that applies a constant tension to the guide wire 22.

FIG. 3 shows a tank accessory handling device (hereinafter referred to as "handling device") 34 according to the present invention, which is used when taking out the float 14 of the liquid level gauge 12 as described above.
Is specified. The handling device 34 includes an airtight box 36 for temporarily storing the float 14 taken out from the nozzle 24 of the liquid level gauge 12. The illustrated airtight box 36 has a substantially cylindrical shape, and has an opening 38 connected to the manhole 28 of the nozzle 24 at one end, and an opening 42 at the other end.
Are hermetically closed by a closing plate 42. The hermetic box 36 is of a so-called glove box type, and is provided with gloves 46 made of an air-tight and flexible material such as rubber on appropriate portions, for example, the closing plate 42 and the side wall 44. The operator operates the inside of the airtight box 36 from outside through the gloves 46. In addition, a viewing window 48 is provided at an appropriate location to view the inside of the airtight box 36.

An auxiliary airtight box 50 is connected to the side wall 44 of the airtight box 36, and the insides of the airtight box 36 and the auxiliary airtight box 50 are communicated with each other. In the sub airtight box 50, there is a liquid level gauge 1
First and second airtight seals for the second nozzle 24
Are accommodated. Seal member 5
Nozzles (cylindrical bodies) 2 to be applied
Although various forms are conceivable depending on the shape of the nozzle 4, the components existing in the nozzle 24, and the like, a balloon-type seal bag as illustrated is preferable. First and second seal bags 5
The reference numerals 2 and 54 are accommodated in a contracted state in the auxiliary airtight box 50 and are appropriately fixed. Hose 56, 58 for taking in gas are connected to each seal bag 52, 54 (FIG. 3).
The other ends of these hoses 56, 58 are connected to the inner ends of nozzles 60, 62 provided on the side wall 44 of the airtight box 36. The nozzles 60 and 62 are connected to a supply source 64 of a suitable inflation gas (for example, an inert gas such as nitrogen gas) for inflating the seal bags 52 and 54 (see FIG. 1).

The airtight box 36 of the handling device 34 has, in addition to the seal bag nozzles 62 and 64, a purge gas nozzle 66 for taking in a purge gas and an exhaust nozzle for discharging the gas inside the airtight box 36 to the outside. 68 are provided.

Next, an operation procedure for replacing the float 14 of the liquid level gauge 12 using such a handling device 34 will be described.

First, in order to connect the airtight box 36 of the handling device 34 to the manhole 28 of the nozzle 24, an adapter tube 70 having an inner diameter substantially equal to the outer diameter of the manhole tube 29 defining the manhole 28 as shown in FIG. prepare. By appropriately replacing the adapter tube 70, the airtight box 36 can be connected to manholes of various shapes in a general-purpose manner. The illustrated adapter tube 70 is of a split type, and a sealing material (not shown) such as an O-ring or packing is provided on the inner peripheral surface. Also, the adapter tube 70
Has an outward flange 72 at one end.

After the adapter tube 70 is attached to the manhole tube 29, the outward flange 72 of the adapter tube 70 is bolted to the inward flange 74 on the opening 34 side of the airtight box 36. At this time, the airtight box 36 has the closing plate 42 removed and the hoses 56, 58 of the seal bags 52, 54.
Is not set, the operator can perform a bolting operation through the inside of the airtight box 36 that is widely opened (see FIG. 1).

Next, the nozzles 60 and 62 for the seal bag are used.
The purge gas supply source 64 is connected to the expansion gas supply source 64, the purge gas supply source 76 is connected to the purge gas nozzle 66, and the exhaust gas processing device 78 is connected to the exhaust nozzle 68. The purge gas is preferably an inert gas such as nitrogen gas, and the exhaust gas treatment device 78 includes at least a sensor 80 for measuring the contents of a tank present in the exhaust gas, for example, a methane concentration meter, and an exhaust gas. A detoxifying device 82, for example, a diluting device for diluting with nitrogen gas, and a blower 84 for forcibly sucking the gas inside the airtight box 36 are preferable.

Subsequently, as shown in FIG. 2A, the first and second seal bags 52, 54 in the contracted state are accommodated in the sub-hermetic chamber 50, and the hoses 56, 58 are respectively connected. It is connected to the inner ends of the nozzles 60 and 62, and the airtight box 36 is sealed with a closing plate 42. After this stage, work on the inside of the airtight box 36 and the nozzle 24 is performed through the gloves 46 until the closing plate 42 is removed.

Thereafter, the blower 84 is operated to supply nitrogen gas as a purge gas to the airtight box 36,
Is replaced with nitrogen gas. This is because the oxygen in the airtight box 36 is removed, and the LN when the manhole 28 is opened is removed.
This is to prevent the emergency combustion of G. In the meantime, the wire 14 is pulled up to collect the float 14 above the nozzle 24.

When the air in the airtight box 36 is replaced with nitrogen gas, the valves of all the lines following the airtight box 36 are closed, and the closing plate 30 of the manhole 28 is removed. And
The first seal bag 52 is moved from the sub airtight box 50 to the airtight box 36.
To the inside of the nozzle 24 from the manhole 28. The position of the first seal bag 52 may be any position as long as it is below the manhole 28, but within a range where the worker can reach through the gloves 46 of the airtight box 36, that is, adjacent to the manhole 28. It is preferable to set the position.

Next, an inflation gas is supplied to the first seal bag 52 through the hose 60 and is inflated.
The outer surface of the seal bag 52 is in close contact with the inner peripheral surface of the nozzle 24, and the internal passage of the nozzle 24 is hermetically sealed (FIG. 2).
(B)). In this state, the guide wire 22 is interposed between the first seal bag 52 and the nozzle 24, but the seal bag 52 is made of a flexible material such as synthetic rubber and extends in the axial direction of the nozzle 24. Because the height along the seal bag 52 is sufficiently ensured, the seal bag 52 follows the outer shape of the guide wire 22, and there is no gap formed around the guide wire 22 as gas leakage.

Here, a nitrogen gas is supplied to a purge gas supply source 76.
From the airtight box 36, and the natural gas inside the airtight box 36 and the upper part of the nozzle 24 is purged through the exhaust nozzle 68 and replaced with nitrogen gas. And wire 1
Disassemble the joint portions 86 and 88 on the closing plate 26 through which the guide wire 8 and the guide wire 22 pass.

Thereafter, the float 14 is lowered to the front of the manhole 28, and the float 14 is pulled out from the manhole 28 together with the wire 18 and the guide wire 22 into the hermetic box 36 as shown in FIG. Then, the joints 86 and 88 on the closing plate 26 are temporarily sealed with a rubber stopper or the like.

Next, the remaining second seal bag 54 is placed in the manhole 28 from the auxiliary airtight box 50, and an inflation gas is supplied thereto to seal the manhole 28 airtightly (see FIG. 2D). ). Thereby, the nozzle 24
Even if one of the seals is incompletely sealed at two places by the two seal bags 52 and 54, there is no fear that the natural gas in the storage tank 10 leaks outside.

If it is confirmed from the value of the methane concentration meter 80 that the methane concentration in the airtight box 36 is stable below the safe value, the closing plate 42 of the airtight box 36 is removed, and the float 14 is replaced with a new float. Replace (see FIG. 2 (e)). If it is desired to increase the accuracy of the liquid level measurement, the float may be replaced with a displacer in order to make the liquid level gauge an equilibrium type.

When the replacement of the float 14 is completed,
The float 14 or the displacer is returned to the storage tank 10 in the reverse procedure. That is, after putting the float 14 and the closing plate 30 of the manhole 28 in the airtight box 36,
The airtight box 36 is closed by the closing plate 42. Then, the second seal bag 54 is contracted and returned to the sub airtight box 50, and the float 14, the wire 18 and the guide wire 22 are returned from the manhole 28 to the upper part of the nozzle 24. Subsequently, the nozzle 24
The first seal bag 52 in the inside is contracted to
Housed inside. After the manhole 28 is airtightly closed by the closing plate 42, the natural gas in the airtight box 36 is purged, and the closing plate 42 of the airtight plate 36 is removed. Further, the airtight box 36 is removed from the adapter tube 70, and finally, the adapter tube 70 is removed from the manhole tube 29.

Although the preferred embodiments of the present invention have been described in detail, it goes without saying that the present invention is not limited to the above embodiments.

For example, in the above embodiment, a balloon-type seal bag is used as the seal member. However, the seal member can be housed in a compact form in an airtight box, and can be inserted from the manhole of the nozzle. Can,
In addition, any structure may be used as long as it can be transformed into a seal form in the nozzle. Specifically, a ring-shaped balloon provided around a disk,
A folding type is conceivable.

The object to be handled is not limited to the float of the liquid level gauge, and the present invention can be similarly applied to other tank accessories that can be taken out from the cylindrical body provided on the tank roof or the tank side wall. .

[0033]

As described above, according to the present invention, when the tank accessory is taken out through the tubular body, the seal is provided at two places, the internal passage of the tubular body and the opening serving as the outlet. It is possible to Therefore, even in a storage tank containing dangerous substances such as LNG, it is possible to safely take out the tank accessories to the outside and replace or repair the tank without emptying the tank.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an embodiment in which the present invention is applied to an LNG storage tank.

FIGS. 2A to 2E are diagrams showing a procedure of a method for handling tank accessories according to the present invention.

FIG. 3 is an exploded perspective view showing one embodiment of a tank accessory handling device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Storage tank, 12 ... Level gauge, 14 ... Float (tank accessory), 24 ... Nozzle (tubular body), 28 ... Manhole (opening), 30 ... Closing plate, 34 ... Tank accessory handling device, 36 ... airtight box, 42 ... closing plate, 46 ... gloves, 5
0: auxiliary airtight box, 52: first seal bag (first seal member), 54: second seal bag (second seal member), 70: adapter tube.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Nakamura 8-19-20 Higashisuna, Koto-ku, Tokyo Inside To-Yokanets Corporation (72) Inventor Yoshio Furuta 8-19-20 Higashisuna, Koto-ku, Tokyo To-Yokanets (56) References JP-A-62-297600 (JP, A) JP-A-48-77708 (JP, U) JP-B-1-23392 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) F17C 1/00-13/12 B65D 88/00-90/66

Claims (2)

(57) [Claims] 1. In a storage tank (10) provided with a tubular body (24) for handling accessories on the tank roof (16) or on the side wall of the tank, the tube is used to handle accessories (14) inside the tank. The accessory (1) through the shape (24)
A tank accessory handling method for taking out 4) to the outside, comprising: a first deformable sealing member (52) for hermetically sealing an internal passage of the tubular body (24); An airtight box (36) containing a deformable second sealing member (54) for hermetically sealing the opening (28) of the body (24) and capable of being operated internally from the outside;
Airtightly connecting to the opening (28) of the tubular body (24); and a closing plate (30) for the opening (28) of the tubular body (24).
And removing the accessory (14) from the tubular body (24).
And a step of hermetically sealing the internal passage of the tubular body (24) with the first sealing member (52) so that the accessory (14) is isolated from the inside of the storage tank (10). The accessory (14) was moved to the hermetic box (36).
Thereafter, a step of hermetically sealing the opening (28) of the tubular body (24) with the second sealing member (54), and opening the hermetic box (36) to remove the accessory (14). Taking out to the outside, and a method for handling tank accessories. 2. An accessory (14) inside a tank used in a storage tank (10) provided with a tubular body (24) for accessory handling on a tank roof (16) or a tank side wall. A tank accessory handling method for taking out the accessory (14) to the outside through the tubular body (24), wherein the accessory can be hermetically connected to an opening (28) of the tubular body (24). An airtight box (36) capable of performing internal operations from outside, and the tubular body (2 ) housed in the airtight box (36).
4) a deformable first seal member (52) for hermetically sealing the internal passage; and the cylindrical body (2 ) housed in the airtight box (36).
4) Deformable to hermetically seal the opening (28)
And a second sealing member (54).