JP2545203B2 - Antifreeze pipe - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifreezing pipe for preventing freezing of a liquid flowing in the pipe.

[0002]

2. Description of the Related Art
As a method to prevent the freezing of the liquid sent in the pipe,
A method of providing a heat insulating material on the outer peripheral portion of the pipe and fixing the heat insulating material with an appropriate covering member such as taping is generally adopted.

However, in the above-mentioned method, the covering member and the heat insulating material are affected by the external environment change, and after several years, they will be broken and a gap will be formed, and further water will intrude from the gap to significantly reduce the heat insulating performance. Therefore, there is a problem in that repair and replacement are required periodically, and maintenance management requires a lot of cost and labor.

Therefore, as an anti-freezing pipe for preventing freezing of a water pipe, an anti-freezing pipe having a vacuum double structure in which an outer cylinder is provided on an outer peripheral portion of a water supply pipe via a vacuum space is disclosed in Japanese Utility Model Laid-Open No. 59-151971. Proposed in the gazette.

Compared with the above-mentioned one in which the contact between the water supply pipe and the outside air is simply shut off, this one has a significantly improved heat insulation performance, and the vacuum space can maintain the initial performance for a long period of time. Easy to manage.

However, in the antifreezing pipe,
Since the connecting portion between the outer cylinder and the water supply pipe has a reducer shape, it is good when the outer cylinder contracts with respect to the water supply pipe, but when the outer cylinder expands with respect to the water supply pipe, the expansion amount is absorbed. There is no place. That is, there is freedom only in one direction.

By the way, as a method of forming a vacuum space, generally, an opening is provided in an outer cylinder attached to a water supply pipe, and internal air is introduced through the opening in a furnace at a high temperature of about 450.degree. There are known a tip tube method to pull out and a vacuum furnace method to seal the opening with a lid in a vacuum furnace at about 1000 ° C, but both are common in that the outer cylinder and the water supply pipe are heated in high temperature. In addition, since the water supply pipe is covered by the outer cylinder, the temperature of the outer cylinder is larger than that of the water supply pipe during heating, and extra stress is generated at both ends of the outer cylinder. There has been a problem that a leak occurs due to a change with time. The present invention has been made to solve the above problems.

[0008]

In order to achieve the above object, the present invention provides an antifreezing pipe having a vacuum space formed between a water supply pipe and an outer cylinder externally mounted on the water supply pipe. At least one end side has a connecting member, which is thinner than the water supply pipe and the outer cylinder, interposed between the outer cylinder and the water supply pipe, and the connecting member is welded and connected to the water supply pipe and the outer cylinder. The outer cylinder end where the member is located is covered with a cap, and a sealant is filled between the cap and the connecting member.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an antifreezing device 1 provided with an antifreezing pipe 7 according to the present invention. A water drain valve 4 is connected to an end of a water supply pipe 2 buried in the ground via an elbow 3, and the water drain valve 4 A drain tap 5 and an antifreezing pipe 7 are connected to 4.

The water drain plug 5 has a shaft 53 inserted therein, and by rotating a water drain cock 52 mounted on the upper part of the shaft 53, a packing 54 mounted on the lower part of the shaft 53 is upstream of the water drain valve 4. The flow path is opened and closed in the section.

As shown in detail in FIG. 2, the antifreezing pipe 7 is roughly composed of a water supply pipe 10, an outer cylinder 11, and connecting members 13 and 14.

The water supply pipe 10 is a stainless pipe having an inner diameter of 22 mm and a thickness of 1 mm, and the outer casing 11 is covered with copper foil, aluminum foil, chemical silver plating or the like.
An appropriate spacer may be provided to keep the gap with the outer cylinder 11 constant and prevent thermal contact between the outer cylinder 11 and the water supply pipe 10 as much as possible. The outer cylinder 11 is a stainless steel pipe having an inner diameter of 42 mm and a thickness of 1.2 mm, a copper tip tube 12 is attached to the outer peripheral portion on the upstream side, and a getter (not shown) is attached to the inner surface on the downstream side. . The connecting members 13 and 14 are ring members formed by processing a stainless steel member thinner than the water supply pipe 10 and the outer cylinder 11 and connecting the portions having a U-shaped cross section in an annular shape. The inner diameter is slightly smaller than the outer diameter of the water supply pipe 10. Large inner ring 13b, 1
4b, outer ring portions 13c, 14c having an outer diameter slightly smaller than the inner diameter of the outer cylinder 11, and inner and outer ring portions 13b, 13
Connection parts 13a, 14a for connecting c, 14b, 14c at a substantially right angle
Consists of

The antifreezing pipe 7 having the above structure is
It is formed as follows. First, as shown in FIG.
The connecting member 13 is installed on the downstream side of the water supply pipe 10 with its U-shaped inner surface facing the downstream side, the point indicated by the arrow A is welded all around, and the connecting member 14 is attached to the upstream end of the outer cylinder 11. The U-shaped inner surface is installed so that it faces the upstream side, and the points indicated by the arrow B are welded all around.

Then, the outer cylinder 11 is packaged from the upstream side of the water supply pipe 10 and the points indicated by arrows C and D are welded all around.
On the outside of the water supply pipe 10, the outer cylinder 11 and the connecting members 13, 1
A space S surrounded by 4 is formed. In addition, water supply pipe 1
When the outer cylinder 11 is externally fitted to 0, since the water supply pipe 10 and the tips of the outer cylinder 11 do not come into contact with the connecting members 14 and 13 up to the final position, it can be easily performed without difficulty. Further, the copper foil or the like provided on the outer surface of the water supply pipe 10 or the getter provided on the inner surface of the outer tube 11 is not damaged.

Next, the tip tube 12 attached to the outer cylinder 11
A vacuum pump (not shown) is connected to the chamber, the air in the space S is extracted to near the vacuum state, and then the water supply pipe 10
Is placed in a furnace (not shown) at about 450 ° C., and the air in the space S is completely extracted in a high temperature state, and the chip tube 12 is crushed to seal the space S (hereinafter referred to as “vacuum space”) S.

At this time, if the material is put into the furnace and heated from the room temperature state, the temperature of the outer cylinder 11 first rises, and then the temperature of the water supply pipe 10 rises later. The expansion amount of the cylinder 11 is large, and the connecting member 1
The outside and the inside of 3 and 14 are deformed by receiving forces in the directions of arrows a and b, respectively.

On the contrary, when the cooling is started, the outer cylinder 11 is cooled faster than the water supply pipe 10. Therefore, the contraction amount of the outer cylinder 11 is large at the time of cooling, which is contrary to the heating.
The connecting members 13 and 14 are deformed by receiving forces in the directions of arrows a ′ and b ′, respectively.

As described above, the connecting members 13 and 14 receive forces in the opposite directions during heating and cooling,
Since the connecting members 13 and 14 have the degrees of freedom in both directions because the connecting portions 13a and 14a form a substantially right angle with respect to the inner ring portions 13b and 14b and the outer ring portions 13c and 14c, an unreasonable stress is generated at the time of deformation. It will not be damaged or damaged. Further, since the connecting members 13 and 14 are thinner than the water supply pipe 10 and the outer cylinder 11, the stress is further relieved due to the weakness of the waist of the connecting members 13 and 14.

Incidentally, as shown in FIG. 4, at least one of the connecting members 13 and 14 does not have to have the connecting portion 13a and the inner and outer ring portions 13b and 13c formed at a substantially right angle. Therefore, the stress can be relieved by the weakness of the waist of itself. Further, as shown in FIG.
3a may have a wavy shape in the radial direction. In this case, the stress can be relieved by the expansion and contraction of the connecting portion 13a.

In the vacuum double structure pipe formed as described above, caps 15 and 16 made of stainless steel are attached to both ends of the outer cylinder 11 and outside of the connecting members 13 and 14, respectively. The sealing agents 17 and 17 are respectively injected between the cap tube 12 and the connecting members 13 and 14, and the tip tube 12 is provided by the downstream side of the cap 16 and another cap 18.
And freeze it with a sealant, etc.
To form. The tip tube 12 may be covered with the cap 19 and the inside thereof may be filled with the sealant 20.

The antifreezing pipe 7 is a water supply pipe 10.
The upstream side of is connected to the elbow 6, is guided under the floor of the building 100 to the room 101, and the downstream side of the water supply pipe 10 is connected to the indoor pipe 103 leading to the tap 102 of the water supply. If necessary, the periphery of the antifreeze pipe 7 may be covered with a heat insulating material.

In the anti-freezing device 1 having the above-mentioned structure, after the faucet 103 is opened and water is used, the drain cock 52 is rotated while flowing water, and the flow path is blocked on the upstream side of the drain valve 4, The water on the downstream side is discharged into the ground through the water outlet 41.

However, even if this water draining operation is forgotten, the water supply pipe 10 is covered with the outer cylinder 11 and the vacuum space S is interposed between the two, so that it is excellent in heat insulation and the temperature under the floor is kept low. Even below the freezing point, the water in the water supply pipe 10 does not freeze in a short time.

According to an experiment conducted by the present inventors,
Even if the upper and lower portions of the antifreezing pipe 7 were kept in an atmosphere of 5 ° C. and exposed to a low temperature condition of −30 ° C. between them, the water inside did not freeze for about 80 hours.

By the way, in a cold region, the soil near the surface may freeze up and the antifreezing pipe 7 may be lifted up. Therefore, the circumference of the outer cylinder 11 is covered with a shrink tube, a pipe or the like to cover the outer cylinder. Isolate 11 and the soil so that the anti-freezing pipe 7 does not rise.
When the caps 17 and 18 for covering the tip tube 12 are projected to the periphery as in the present embodiment, the resistance at the time of freezing is increased and the effect of preventing freezing is further enhanced.

In the above embodiment, the antifreezing pipe 7 according to the present invention is applied to the antifreezing device 1. However, the antifreezing pipe 7 is not limited to this, and in short, internal It can be applied to any place for the purpose of preventing freezing of the liquid.

Further, in the above embodiment, the vacuum space S is formed by the tip tube system, but the invention is not limited to this.
A vacuum furnace system may be used.

Further, in the above-described embodiment, the connecting members 13 and 14 having U-shaped cross sections are arranged at both ends of the outer cylinder 11 so that the inner surfaces of the connecting members 13 and 14 are located on the outer side. You may make the character-shaped inner surfaces face each other,
Connect the connecting members 13 and 14 to the upper and lower parts
It may be bent by 0 ° and may have a substantially Z-shaped cross section. Furthermore,
At least one of the connecting members 13 and 14 having the above-described shape is provided, and at the other end, the end portion of the outer cylinder 11 is contracted to provide the water supply pipe 10.
May be connected to.

If the axial welding lines of the water supply pipe 10 and the outer cylinder 11 are made to coincide with each other, they will warp in the same direction during heating, and the outer surface of the water supply pipe 10 and the outer cylinder 11 will be warped.
There is no contact with the inner surface of the.

[0030]

As is apparent from the above description, the antifreezing pipe according to the present invention has at least one end side of the outer cylinder,
The water supply pipe and the outer cylinder are connected to the water supply pipe by a connecting member thinner than the outer pipe. Therefore, the initial insulation performance can be maintained over a long period of time and maintenance is easy, of course.
In the manufacturing process, even if it is placed in a high temperature furnace or a vacuum furnace and heated and cooled, the difference in relative expansion and contraction amount of the pipe and outer cylinder is absorbed by the thin connecting member, and extra stress is generated. To prevent cracks from occurring in the pipe and outer cylinder.

Further, the yield of products can be improved and the productivity can be improved. Further, since the welded portion between the water supply pipe and the outer cylinder and the connecting member is protected by the cap and the sealant, there is an effect that damage and corrosion of the welded portion are prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an antifreezing device.

FIG. 2 is a partially cutaway side view of an antifreezing pipe.

FIG. 3 is a partially cutaway side view showing an assembled state of the antifreezing pipe.

FIG. 4 is a sectional view showing another embodiment of the connecting member.

FIG. 5 is a cross-sectional view showing another embodiment of the connecting member.

[Explanation of symbols]

1 ... Antifreeze device, 2 ... Water supply pipe, 4 ... Water drain valve, 5 ...
Water stopper, 7 ... Antifreeze pipe, 10 ... Water supply pipe, 1
1 ... Outer cylinder, 12 ... Tip tube, 13, 14 ... Connection member

Claims (1)

(57) [Claims] 1. A freeze-prevention pipe having a vacuum space formed between a water supply pipe and an outer cylinder externally mounted on the water supply pipe, wherein at least one end side of the outer cylinder is provided between the outer cylinder and the water supply pipe. A connecting member thinner than the water supply pipe and the outer cylinder is interposed, and the connecting member is welded and connected to the water supply pipe and the outer cylinder, and the outer cylinder end where the connecting member is located is covered with a cap. An antifreeze pipe, characterized in that a sealant is filled between the pipe and the connecting member.