JP3597015B2 - Insulated pipe and spacer for insulated pipe - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat insulation pipe suitable for heat insulation of a cryogenic cable or a refrigerant transport pipe, and a heat insulation pipe spacer.
[0002]
[Prior art]
FIG. 5 shows an example of a heat insulating tube such as a cryogenic cable (see Japanese Utility Model Publication No. 53-51426). This is a heat insulating tube in which a laminated heat insulating layer 13 is disposed between the corrugated inner tube 11 and the corrugated outer tube 12, and a vacuum is formed between the two tubes 11, 12.
[0003]
[Problems to be solved by the invention]
However, in the above-mentioned heat-insulating pipe, when evacuation is performed, the evacuation path has a spiral shape along the corrugated groove of the inner and outer pipes, so that a path along the longitudinal direction cannot be secured. In particular, when the heat insulating pipe is lengthened, when the corrugated pitch of the inner and outer pipes is reduced, and when the diameter of the heat insulating pipe is increased, the exhaust path becomes significantly longer. Since the efficiency of evacuation is inversely proportional to the length of the evacuation path, the evacuation efficiency of a conventional heat insulating pipe is extremely low.
[0004]
Therefore, a main object of the present invention is to provide a heat insulating pipe and a heat insulating pipe spacer capable of securing a longitudinal exhaust path between the inner and outer pipes to facilitate vacuuming and coaxially holding the inner and outer pipes. is there.
[0005]
[Means for Solving the Problems]
The heat insulating tube of the present invention achieves the above-mentioned object, and is characterized in that a heat insulating material and a spacer are provided between the corrugated inner and outer tubes, and the heat insulating tube for keeping a vacuum between the inner and outer tubes is provided. A plurality of cylindrical bodies are arranged in parallel at predetermined intervals and integrated with a band-like body, wound spirally around the outer circumference of the inner pipe, and this cylindrical body is arranged along the axial direction of the inner and outer pipes. Features.
[0006]
Here, the position where the spacer is arranged may be anywhere between the inner tube and the outer tube. That is, a spacer may be wound on the inner tube and a heat insulating material may be arranged thereon, or conversely, a heat insulating material may be arranged on the inner tube and the spacer may be wound thereon.
[0007]
Further, the spacer of the present invention used for the heat insulating pipe is such that a plurality of cylinders are arranged in parallel at a predetermined interval, and these are integrated by a band, and each cylinder has an inclination with respect to the longitudinal direction of the band. Features.
[0008]
It is preferable that the material of the spacer is made of a material that emits little gas for both the band and the cylinder. That is, a material having a gas release rate of 10 ⁻² (Pa · m ³ / s · m ² ) or less is preferable. This configuration improves the evacuation efficiency and is effective in maintaining the degree of vacuum between the inner and outer tubes. Specific examples of materials that emit little gas include metals such as iron, stainless steel, lead, copper, aluminum, steatite, viton, and araldite, and fluororesins <polytetrafluoroethylene>, polystyrene, polyvinyl chloride, and neoprene. And synthetic rubbers and resins such as polyamide resins, and other glass. References regarding the gas release rates of various substances include “Vacuum technology”, Horikoshi, University of Tokyo Press, 1994.
[0009]
The configuration of the belt-like body is preferably a net shape from the viewpoint of securing the exhaust path. The integration of the band and the cylinder includes bonding with an adhesive.
[0010]
The cylindrical body used for the spacer may be a hollow cylinder or a solid cylinder. A hollow cylinder is preferable in that the exhaust path can be easily secured and the weight is light. Further, the outer diameter of the cylindrical body is set to an extent that the space between the inner and outer pipes of the heat insulating pipe can be sufficiently held. By setting the length of the cylindrical body to 5 to 10 times the corrugated pitch of the inner pipe or the outer pipe, it is possible to prevent the cylindrical body from bending and damaging the heat insulating material when the heat insulating pipe is bent.
[0011]
The angle of inclination of the cylindrical body with respect to the longitudinal direction of the belt-shaped body is determined so that the cylindrical body follows the axial direction of the inner and outer tubes when the spacer is wound. This angle of inclination is determined by the width of the strip, the diameter of the portion where the spacer is wound, and the winding pitch.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a schematic perspective view of the heat insulating tube of the present invention, and FIG. 2 is a cross sectional view of the heat insulating tube.
In the heat insulating tube of the present invention, a laminated heat insulating material 3 and a spacer 4 are arranged between a corrugated inner tube 1 and a corrugated outer tube 2 to maintain a vacuum between both the tubes 1 and 2.
[0013]
The inner tube 1 and the outer tube 2 are made of an aluminum alloy material. A core (not shown) of a superconducting cable and the like are built in the inner periphery of the inner tube 1, and a laminated heat insulating material 3 is wound around the outer periphery of the inner tube 1. The laminated heat insulating material 3 is usually formed by laminating an aluminum vapor-deposited film, a glass tape, or the like.
[0014]
The spacer 4 of the present invention is arranged between the heat insulating material 3 and the outer tube 2. The plan view is shown in FIG. The spacer 4 is configured by arranging a plurality of cylindrical bodies 5 at predetermined intervals in parallel, and integrating these with a net-like band-like body 6. The band 6 uses a glass net, and the cylindrical body uses a glass pipe. The cylindrical body 5 has both ends aligned with both side edges of the band 6 and is fixed at a fixed angle θ with respect to the longitudinal direction of the band 6. The angle θ is set so that when the spacer is wound around the outer periphery of the heat insulating material 3, each cylindrical body 5 extends along the axial direction of the inner and outer tubes 1 and 2 (see FIG. 1). The arrangement interval t of the cylinders 5 was set such that the cylinder 5 divides the circumferential direction into eight equal parts when the spacer 4 was wound (see FIG. 2). The interval t may be set to an extent that the inner and outer tubes 1 and 2 can be held coaxially when the spacer is wound. The length of the cylindrical body 5 was about twice the corrugated pitch of the outer tube 2.
[0015]
With such a configuration, the inner and outer tubes 1 and 2 can be held coaxially, and an exhaust path can be secured in the longitudinal direction of the heat insulating tube. That is, a space that is continuous in the longitudinal direction is formed between the cylindrical bodies 5, and a sufficient exhaust path can be secured during evacuation.
[0016]
Further, even when the heat insulating pipe is bent, the cylindrical body 5 does not bend and the heat insulating material is not damaged. Furthermore, since the spacer having such a configuration can be easily installed simply by winding, the spacer can be mounted in a short time without any special skill in mounting the spacer.
[0017]
A calculation example of the exhaust conductance when the conventional heat insulating pipe and the heat insulating pipe of the present invention are evacuated will be described below.
In a conventional heat insulating tube, as shown in FIG. 4A, a helical space formed between the outer tube 12 and the heat insulating material 13 is assumed to allow a molecular flow to flow. Is approximated by the following equation.
D {2} (δP / 2π) ... Equation 1
δ = depth of the valley of the corrugated pipe, P = corrugated pitch Further, the length L of the flow path per 1 m of the pipe is expressed by the following equation (2).
L ≒ πd (100 / P) ... Equation 2
d = the diameter of the spiral conduit and the circular tube conductance V is
V = 65D ³ / (L√M) Equation 3
M ≒ 29 (air molecular weight)
Thus, by substituting Equations 1 and 2 into Equation 3, and substituting δ = 0.6 (cm), P = 20 (cm), d = 10 (cm), and L = 100 (cm), The conductance V per meter of pipe is 0.308 (l / mim).
[0018]
On the other hand, in the heat insulating tube of the present invention, the conductance V is determined by the following equation of the cylindrical tube.
V = 10 ³ α (D ₁ −D ₂ ) ² (D ₁ + D ₂ ) / 48Lπ√M
Here, the outer tube radially innermost _D 1 = 11.5 (cm), the outermost inner pipe diameter _{D 2 = 9.9 (cm),} α = 1.5, and substituting L = 100 (cm) pipe 1m The conductance V per hit is 60.7 (l / mim).
Thus, it can be confirmed by calculation that the heat insulating pipe of the present invention can secure a sufficiently large exhaust path.
[0019]
【The invention's effect】
As described above, according to the heat insulating pipe of the present invention, the inner and outer pipes can be held coaxially, the exhaust path in the longitudinal direction can be secured, and the evacuation can be performed efficiently.
Further, the spacer of the present invention is most suitable for constituting the heat insulating tube of the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a configuration of a heat insulating tube of the present invention.
FIG. 2 is a cross-sectional view of the heat insulating tube of the present invention.
FIG. 3 is a plan view of the spacer of the present invention.
FIG. 4A is a vertical cross-sectional view of a corrugated pipe and a heat insulating portion of a conventional heat insulating pipe, and FIG. 4B is a schematic view showing an exhaust path of the conventional heat insulating pipe.
FIG. 5 is a partial sectional view of a conventional heat insulating tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner pipe 2 Outer pipe 3 Heat insulating material 4 Spacer 5 Cylindrical body 6 Belt

Claims (7)

A corrugated outer tube arranged at normal temperature, a corrugated inner tube arranged inside the outer tube, a heat insulating material and a spacer arranged between the inner and outer tubes, and a space between the inner and outer tubes. In an insulated tube that holds a vacuum,
The spacer, a plurality of cylindrical bodies are arranged in parallel at predetermined intervals and integrated with a band-shaped body, spirally wound around the outer circumference of the inner tube,
This cylindrical body is arranged along the axial direction of the inner and outer tubes ,
A heat insulating pipe, wherein the strip is net-shaped . A corrugated outer tube arranged at normal temperature, a corrugated inner tube arranged inside the outer tube, a heat insulating material and a spacer arranged between the inner and outer tubes, and a space between the inner and outer tubes. In an insulated tube that holds a vacuum,
The spacer, a plurality of cylindrical bodies are arranged in parallel at predetermined intervals and integrated with a band-shaped body, spirally wound around the outer circumference of the inner tube,
This cylindrical body is arranged along the axial direction of the inner and outer tubes ,
A heat insulating pipe, wherein the material constituting the band and the cylinder has a gas release rate of 10 ^-2 (Pa · m ³ / s · m ² ) or less . The heat insulating pipe according to claim 1 or 2 , wherein the length of the cylindrical body is set to be 5 to 10 times the corrugated pitch of the inner and outer pipes. In the cross section of the heat insulating pipe, each cylindrical body is arranged at intervals equally dividing the circumferential direction of the inner and outer pipes, and a space continuous in the longitudinal direction is formed between the cylindrical bodies. Item 3. The heat insulating tube according to item 1 or 2 . The heat insulating pipe according to claim 1, wherein the cylindrical body is hollow. It has a corrugated outer tube arranged at room temperature, a corrugated inner tube arranged inside the outer tube, and a heat insulating material arranged between the inner and outer tubes, and a vacuum is applied between the inner and outer tubes. A heat insulating tube spacer used for the held heat insulating tube,
A net-like band disposed between the inner and outer tubes together with the heat insulating material,
Having a plurality of cylindrical bodies integrated with a band in a state of being arranged in parallel at predetermined intervals,
A spacer for a heat insulating pipe, wherein each cylindrical body has an inclination with respect to a longitudinal direction of the band-shaped body. It has a corrugated outer tube arranged at room temperature, a corrugated inner tube arranged inside the outer tube, and a heat insulating material arranged between the inner and outer tubes, and a vacuum is applied between the inner and outer tubes. A heat insulating tube spacer used for the held heat insulating tube,
A strip disposed between the inner and outer tubes together with the heat insulating material,
Having a plurality of cylindrical bodies integrated with a band in a state of being arranged in parallel at predetermined intervals,
Each cylinder has an inclination with respect to the longitudinal direction of the band,
A spacer for a heat-insulating pipe, wherein the material constituting the strip and the cylinder has a gas release rate of 10 ^-2 (Pa · m ³ / s · m ² ) or less .

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