JP7652416B2 - Vacuum double piping and fluid equipment connection structure - Google Patents

Description

The present invention relates to a connection structure between a vacuum double pipe and a fluid device.

In order to transport low-temperature fluids such as liquefied hydrogen, vacuum double piping has been used in the past, in which a vacuum layer is formed between an inner pipe through which the low-temperature fluid passes and an outer pipe that covers the inner pipe. Fluid equipment such as valves may be connected to the vacuum double piping, and Patent Document 1 discloses a vacuum insulated valve that opens and closes the flow path of the low-temperature fluid transported by such vacuum double piping.

Japanese Utility Model Application Publication No. 4-62498

The vacuum insulated valve disclosed in the above-mentioned Patent Document 1 is connected to the vacuum double piping by screwing together screws, and can be removed from the vacuum double piping for maintenance.

However, this caused the vacuum layer of the double vacuum pipe to be exposed to the atmosphere, which meant that it took a long time to return the vacuum layer to its original vacuum state when maintenance was completed.

The present invention aims to provide a connection structure between a vacuum double pipe and a fluid device that allows for quick and easy maintenance of the fluid device connected to the vacuum double pipe.

The object of the present invention is to provide a connection structure between a vacuum double pipe and a fluid device, the vacuum double pipe comprising an inner pipe through which a low-temperature fluid passes and an outer pipe covering the inner pipe, a vacuum layer being formed between the inner pipe and the outer pipe, the vacuum layer being formed with an isolation section between an upstream partition member and a downstream partition member provided along a flow path, the isolation section being capable of communicating with a portion of the vacuum layer other than the isolation section by a bypass flow path having an on-off valve, the fluid device being provided in the inner pipe in the isolation section, and at least a portion of the outer pipe being configured to be removable, and the upstream partition member and the downstream partition member being configured to be connected to each other by a bypass flow path having an on-off valve, The members are supported by both the inner tube and the outer tube so that they can expand and contract in the radial and longitudinal directions of the vacuum double piping, and at least one of the upstream partition member and the downstream partition member has an inner tube side mounting portion and an outer tube side mounting portion which protrude in a ring shape at a distance from each other in the longitudinal direction from the inner tube and the outer tube, respectively, and a bellows tube attached between the inner tube side mounting portion and the outer tube side mounting portion, and this is achieved by a connection structure between the vacuum double piping and fluid equipment, in which a mounting ring having a plurality of long holes extending radially is provided at the opening edge at at least one end of the bellows tube.

In this connection structure between the vacuum double pipe and the fluid device, it is preferable that at least a portion of the isolation section of the outer pipe is constructed by combining a pair of semi-cylindrical divided bodies into a cylindrical shape, and the divided bodies can be removed in the radial direction.

The fluid device may be a valve, and it is preferable that at least a portion of the outer tube is removable downstream of the fluid device.

The present invention provides a connection structure between a vacuum double pipe and a fluid device that allows for quick and easy maintenance of the fluid device connected to the vacuum double pipe.

1 is a cross-sectional view showing a connection structure between a vacuum double pipe and a fluid device according to an embodiment of the present invention. 2A and 2B are diagrams showing the main parts of the vacuum double pipe shown in FIG. 1, in which FIG. FIG. 2 is a cross-sectional view showing a state in which a part of the vacuum double pipe shown in FIG. 1 is removed. 2 is a cross-sectional view showing another main part of the vacuum double piping shown in FIG. 1. FIG. 5 is a front view of the main part of FIG. 4 . FIG. 2 is a diagram showing a modification of the main part shown in FIG. 1 . FIG. 11 is a cross-sectional view showing a connection structure between a vacuum double pipe and a fluid device according to another embodiment of the present invention.

One embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a connection structure between a vacuum double pipe 1 and a fluid device 100 according to one embodiment of the present invention. As shown in FIG. 1, the vacuum double pipe 1 has an inner pipe 10 and an outer pipe 20 made of a metal material such as stainless steel, and a low-temperature fluid such as liquefied hydrogen, liquefied ammonia, liquefied helium, liquefied nitrogen, or liquefied oxygen passes through the inside of the inner pipe 10 in the direction of the arrow F.

The outer pipe 20 is arranged concentrically with the inner pipe 10 so as to cover the inner pipe 10, and a vacuum layer 30 is formed between the inner pipe 10 and the outer pipe 20. The vacuum layer 30 is evacuated by a vacuum pump (not shown) to vacuum insulate the inner pipe 10.

The fluid device 100 is a valve, and includes a valve box 102, a valve element 104 disposed within the valve box 102, and a valve shaft 106 that rotatably supports the valve element 104. The upstream and downstream sides of the valve box 102 are hermetically flange-connected to the upstream portion 10a and downstream portion 10b of the inner pipe 10 with fasteners such as bolts and nuts, and the flow path of the inner pipe 10 can be opened and closed by rotating the valve element 104 around the valve shaft 106.

The upstream portion 10a and downstream portion 10b of the inner pipe 10 are divided into first portions 11a and 11b, second portions 12a and 12b, and third portions 13a and 13b, in that order from the fluid device 100 side, which are hermetically flanged together.

The outer pipe 20 has a cover portion 29 that covers the fluid device 100, and an upstream portion 20a and a downstream portion 20b that are hermetically flanged to the upstream and downstream sides of the cover portion 29, respectively. The valve shaft 106 of the fluid device 100 extends outward through the cover portion 29.

The upstream portion 20a and downstream portion 20b of the outer pipe 20 are divided into first portions 21a, 21b, second portions 22a, 22b, and third portions 23a, 23b, in that order from the cover portion 29 side. The first portions 21a, 21b, second portions 22a, 22b, and third portions 23a, 23b of the outer pipe 20 are disposed at positions corresponding to the first portions 11a, 11b, second portions 12a, 12b, and third portions 13a, 13b of the inner pipe 10, respectively.

The upstream portions 10a, 20a of the inner pipe 10 and the outer pipe 20 are provided with an inner pipe side mounting portion 14a and an outer pipe side mounting portion 24a, respectively. The inner pipe side mounting portion 14a and the outer pipe side mounting portion 24a are formed in a ring shape and are fixed by welding or the like to the outer peripheral surface of the second portion 12a and the inner peripheral surface of the second portion 22a, respectively, so as to fit along the cross section of the vacuum double pipe 1.

The inner pipe side mounting part 14a and the outer pipe side mounting part 24a are arranged at a distance in the longitudinal direction of the inner pipe 10 and the outer pipe 20, and a bellows tube 31a that can expand and contract in the axial direction is attached between the inner pipe side mounting part 14a and the outer pipe side mounting part 24a. The inner pipe side mounting part 14a, the outer pipe side mounting part 24a, and the bellows tube 31a form an upstream partition member 32a that blocks the vacuum layer 30 in the longitudinal direction of the inner pipe 10 and the outer pipe 20.

The downstream portions 10b, 20b of the inner pipe 10 and the outer pipe 20 are provided with an inner pipe side mounting portion 14b and an outer pipe side mounting portion 24b, respectively, in the same manner as the upstream portions 10a, 20a. The inner pipe side mounting portion 14b and the outer pipe side mounting portion 24b are formed in a ring shape and are fixed by welding or the like to the outer peripheral surface of the second portion 12b and the inner peripheral surface of the second portion 22b, respectively, so as to fit along the cross section of the vacuum double pipe 1.

The inner pipe side mounting part 14b and the outer pipe side mounting part 24b are arranged at a distance in the longitudinal direction of the inner pipe 10 and the outer pipe 20, and a bellows tube 31b that can expand and contract in the axial direction is attached between the inner pipe side mounting part 14b and the outer pipe side mounting part 24b. The inner pipe side mounting part 14b, the outer pipe side mounting part 24b, and the bellows tube 31b constitute a downstream partition member 32b that blocks the vacuum layer 30 in the longitudinal direction of the inner pipe 10 and the outer pipe 20. Between the upstream partition member 32a and the downstream partition member 32b of the vacuum layer 30, an isolation part 33 that is separated from the other parts of the vacuum layer 30 is formed.

A bypass flow path 34a is formed in the upstream portion 20a of the outer pipe 20 by piping that connects the upstream side and downstream side of the upstream partition member 32a in the vacuum layer 30. An opening/closing valve 35a is provided in the bypass flow path 34a, and the bypass flow path 34a can be opened and closed by operating the opening/closing valve 35a.

A bypass flow path 34b is formed in the downstream portion 20b of the outer pipe 20 by piping that connects the upstream side and downstream side of the downstream partition member 32b in the vacuum layer 30. An opening/closing valve 35b is provided in the bypass flow path 34b, and the bypass flow path 34b can be opened and closed by operating the opening/closing valve 35b.

Figure 2 shows the first part 21b in the downstream part 20b of the outer pipe 20 shown in Figure 1, with Figure 2(a) being a front view and Figure 2(b) being a side view. As shown in Figures 2(a) and (b), the first part 21b has a pair of divided bodies 25, 26 formed in a semi-cylindrical shape, and is configured by combining these divided bodies 25, 26 to form a cylindrical shape. On both circumferential sides of the divided bodies 25, 26, there are provided band-shaped flange portions 251, 261 extending in the axial direction, and the flange portions 251, 261 are airtightly joined to each other with fasteners such as bolts and nuts, and the divided bodies 25, 26 can be removed in the radial direction indicated by the arrows by removing the fasteners.

The first portion 21a in the upstream portion 20a of the outer pipe 20, the first portion 11a in the upstream portion 10a of the inner pipe 10, and the first portion 11b in the downstream portion 10b of the inner pipe 10 are also constructed by combining a pair of semi-cylindrical divided bodies 25, 26 into a cylindrical shape, similar to the first portion 21b described above, and the divided bodies 25, 26 can be removed radially.

The connection structure between the vacuum double pipe 1 having the above configuration and the fluid device 100 can connect the entire vacuum layer 30 by opening both the on-off valves 35a and 35b of the bypass flow paths 34a and 34b, and the entire vacuum layer 30 can be evacuated in the same way as with conventional vacuum double pipes.

On the other hand, during maintenance of the fluid device 100, the on-off valves 35a and 35b are both closed to isolate the isolation section 33 from the rest of the vacuum layer 30. After that, the pair of dividers 25, 26 (see FIG. 2) of the first section 21b in the downstream section 20b of the outer tube 20 and the first section 11b in the downstream section 10b of the inner tube 10 are radially removed to form a maintenance space M downstream of the fluid device 100 for performing maintenance of the fluid device 100, as shown in FIG. 3.

By forming the maintenance space M, the isolated portion 33 of the vacuum layer 30 is opened to the atmosphere, but the portion of the vacuum layer 30 other than the isolated portion 33 (the portion with the dot pattern) is maintained in a vacuum state. After maintenance is completed, the maintenance space M is returned to the state shown in FIG. 1, and the on-off valves 35a and 35b of the bypass flow paths 34a and 34b are both opened to perform a vacuum, thereby putting the entire vacuum layer 30 into a vacuum state.

According to the connection structure between the vacuum double pipe 1 and the fluid device 100 of this embodiment, by limiting the release of the vacuum layer 30 to only a partial amount of air during maintenance of the fluid device 100, the vacuum layer 30 can be returned to its original vacuum state in a short time after maintenance is completed. Therefore, maintenance of the fluid device 100 connected to the vacuum double pipe 1 can be performed quickly and easily.

In this embodiment, the first portion 21a in the upstream portion 20a of the outer pipe 20 and the first portion 11a in the upstream portion 10a of the inner pipe 10 are also configured with a pair of division bodies 25, 26 as shown in FIG. 2, so that a maintenance space can also be formed upstream of the fluid device 100. However, if a maintenance space is not required upstream of the fluid device 100, the first portions 11a, 21a may be configured indivisible.

The formation of a maintenance space for performing maintenance on the fluid device 100 can be achieved by configuring at least a portion of the outer tube 20 to be removable, and in addition to the configuration of this embodiment, for example, the formation of a maintenance space can be achieved by configuring an opening formed in the outer tube 20 to be openable and closable with a lid.

The connection points of the bypass flow paths 34a and 34b to the outer pipe 20 are not particularly limited as long as they are positions that allow the isolation section 33 to communicate with other parts of the vacuum layer 30. In this embodiment, as shown in FIG. 1, both ends of the upstream bypass flow path 34a are connected to the first part 21a and the second part 22a, and both ends of the downstream bypass flow path 34b are connected to the second part 22b. Instead of providing the downstream bypass flow path 34b, the upstream bypass flow path 34a may be branched and connected to the downstream side of the isolation section 33.

The upstream partition member 32a and downstream partition member 32b forming the isolating section 33 may be configured to hermetically separate the vacuum layer 30, and may be, for example, a ring-shaped partition member that is interposed when the inner pipe 10 and the outer pipe 20 are formed by flange connection. However, since the inner pipe 10 expands and contracts due to temperature changes of the low-temperature fluid passing through it, the upstream partition member 32a and downstream partition member 32b of this embodiment are supported by both the inner pipe 10 and the outer pipe 20 so that they can expand and contract in the longitudinal direction of the vacuum double pipe 1 by being provided with bellows pipes 31a and 31b, and furthermore, can expand and contract in the radial direction of the vacuum double pipe 1 as described later.

The bellows tube 31a of the upstream bulkhead member 32a shown in FIG. 1 has an attachment ring 36a at the opening edge of one downstream end, and the upstream side of the bellows tube 31a is attached directly to the inner tube attachment part 14a, while the downstream side of the bellows tube 31a is attached to the outer tube attachment part 24a via the attachment ring 36a.

Figure 4 is a cross-sectional view showing a main part of the upstream bulkhead member 32a shown in Figure 1. As shown in Figure 4, the mounting ring 36a has a long hole 37a extending in the radial direction, and the mounting ring 36a is supported so as to be movable in the radial direction relative to the outer pipe side mounting part 24a by inserting a bolt 38 through the long hole 37a and screwing it into a threaded hole in the outer pipe side mounting part 24a. As shown in the front view of Figure 5, the long holes 37a of the mounting ring 36a are arranged in a circumferentially balanced manner so that multiple long holes 37a face each other with the center in between.

Like the upstream bulkhead member 32a, the downstream bulkhead member 32b is also provided with a mounting ring 36b at the opening edge at one end of the upstream side of the bellows tube 31b, and is configured to be expandable in the radial and longitudinal directions of the vacuum double piping 1.

Figure 6 shows a modified version of the main part of the upstream bulkhead member 32a shown in Figure 1, with mounting rings 36a, 36a provided on the opening edges at both ends of the bellows tube 31a. Each mounting ring 36a has multiple elongated holes 37a extending in the radial direction, and is attached to the inner tube mounting part 14a and the outer tube mounting part 24a using these elongated holes 37a.

Figure 7 is a cross-sectional view showing a connection structure between a vacuum double pipe 1 and a fluid device 100 according to another embodiment of the present invention, showing another modified example of the upstream bulkhead member 32a and the downstream bulkhead member 32b. The upstream bulkhead member 32a and the downstream bulkhead member 32b shown in Figure 7 are made of bent members formed in a ring shape and bent so that the radial center portion 39 protrudes in the axial direction of the vacuum double pipe 1. The inner peripheral edge portion and the outer peripheral edge portion of this bent member are clamped when the inner pipe 10 and the outer pipe 20 are flange-connected, and are supported by the inner pipe 10 and the outer pipe 20. The upstream bulkhead member 32a and the downstream bulkhead member 32b configured in this manner can also expand and contract in the radial and longitudinal directions of the vacuum double pipe 1.

The configuration of the fluid device 100 to which the vacuum double pipe 1 is connected is not particularly limited. For example, as shown in FIG. 7, if a maintenance hole 108 for performing maintenance inside the valve box 102 is provided downstream of the valve box 102, at least the portion U directly above the maintenance hole 108 in the outer pipe 20 can be configured to be removable, so that the maintenance cover 109 of the maintenance hole 108 can be opened and closed. In addition, the fluid device 100 is not necessarily limited to a valve, as long as it is any type of fluid device through which a low-temperature fluid passes, is supplied, or discharged, and may be, for example, a flow meter, a pump, an accumulator, a tank, a heat exchanger, etc.

Reference Signs List 1 Vacuum double pipe 10 Inner pipe 14a, 14b Inner pipe side mounting portion 20 Outer pipe 24a, 24b Outer pipe side mounting portion 25, 26 Divider 30 Vacuum layer 31a, 31b Bellows pipe 32a Upstream side partition member 32b Downstream side partition member 33 Isolation portion 34a, 34b Bypass flow path 35a, 35b Opening/closing valve 36a, 36b Mounting ring 37a, 37b Long hole 100 Fluid equipment

Claims (3)

A connection structure between a vacuum double pipe and a fluid device,
The vacuum double pipe includes an inner pipe through which a low-temperature fluid passes and an outer pipe covering the inner pipe, and a vacuum layer is formed between the inner pipe and the outer pipe,
an isolation section is formed between an upstream partition member and a downstream partition member provided along the flow path in the vacuum layer, and the isolation section is capable of communicating with a portion of the vacuum layer other than the isolation section through a bypass flow path having an on-off valve;
In the isolation section, the fluid device is provided in the inner tube, and at least a portion of the outer tube is configured to be removable,
the upstream partition member and the downstream partition member are supported by both the inner pipe and the outer pipe, respectively, so as to be expandable and contractable in a radial direction and a longitudinal direction of the vacuum double pipe;
at least one of the upstream partition member and the downstream partition member includes an inner pipe side mounting portion and an outer pipe side mounting portion protruding in a ring shape at a distance from each other in the longitudinal direction from the inner pipe and the outer pipe, respectively, and a bellows tube mounted between the inner pipe side mounting portion and the outer pipe side mounting portion,
A connection structure between a vacuum double pipe and a fluid device , in which a mounting ring having a plurality of radially extending long holes is provided on the opening edge portion at at least one end of the bellows pipe . The connection structure between vacuum double piping and fluid equipment according to claim 1, in which at least a portion of the isolation section of the outer pipe is formed by combining a pair of semi-cylindrical divided bodies into a cylindrical shape, and the divided bodies can be removed in the radial direction. 3. The connection structure between a vacuum double pipe and a fluid device according to claim 1 , wherein the fluid device is a valve, and at least a portion of the outer pipe is removable on the downstream side of the fluid device.

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