JPS6115356Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a device for preventing thermal shock occurring at a confluence of two fluids having different temperatures.

In areas where fluids with different temperatures converge, the fluids interact in a complex manner, causing the temperature of structural materials such as the inner surface of pipes through which the fluids pass to fluctuate periodically or irregularly, causing thermal stress to occur in the structural materials. In extreme cases, this thermal stress fluctuation may cause thermal fatigue and damage to the structural materials.

Conventionally, as a means of mitigating such thermal shock, a sleeve a called a so-called thermal sleeve is attached to the inner surface of the main pipe b, as shown in FIG. At the same time, the fluid flowing from the confluence pipe d is made to flow through the outer circulation part e formed on the outside of the sleeve a. That is, two types of fluids having different temperatures exchange heat through the sleeve a, and after the temperature difference is alleviated to some extent, they are mixed at the outlet of the sleeve a and flow out into the main pipe b.

However, in the case of this conventional example, the fluid flowing out from the sleeve a immediately comes into contact with the inner surface of the main pipe b, and at this part merges with another fluid having a temperature difference flowing through the outer flow section e. The temperature distribution in a part of the main pipe b became unstable, and there was a possibility that thermal stress would occur and cause thermal fatigue. Particularly in cases where structural materials are required to have strict durability, such as in nuclear power generation facilities, a more effective thermal shock prevention device is desired in order to suppress the occurrence of thermal shock.

This idea was made based on the above circumstances, and its purpose is to reliably prevent thermal shock that occurs in the confluence region of two types of fluids with different temperatures, and to provide heat that can protect structural materials such as pipes. An object of the present invention is to provide a shock prevention device.

This invention will be explained below with reference to an embodiment shown in FIG. In the figure, 1 is a main pipe, and 2 is a confluence pipe connected in the middle of the main pipe, and fluids having different temperatures flow through the main pipe 1 and the confluence pipe 2. The merging pipe 2 is connected to the main pipe 1 by, for example, welding. The main manager 1 above is
As an example, a primary cooling system piping of a nuclear reactor, and a water supply piping flowing into this primary cooling system piping as the merging pipe 2 can be considered.

And the connection part between these pipes, that is, the confluence port 3
A first sleeve 4 made of a material that is thinner than the main pipe 1 and has excellent thermal conductivity is disposed inside the main pipe 1 . The first sleeve 4 has a tapered guide portion 4a at its entrance, and the outer peripheral edge of the guide portion 4a is fixed on the upstream side of the merging port 3 by means such as welding. The fluid flowing from the upstream side of the main pipe 1 is guided to an inner flow section 5 formed within the sleeve 4. Further, an outer flow portion 6 is formed between the outer surface of the first sleeve 4 and the inner surface of the main pipe 1, through which the fluid of the merging pipe 2 flowing from the merging port 3 flows.

A second sleeve 7 is provided downstream of the first sleeve 4. This second sleeve 7 has a larger diameter than the first sleeve 4 and has a larger diameter than the main pipe 1.
It has a smaller outer diameter. The outlet portion 4b of the first sleeve 4 is inserted, and an annular flow gap 8 connected to the outer flow portion 6 is formed in this insertion portion.
is formed. Also, the second sleeve 7 and the main pipe 1
A heat shielding gap 9 is formed between the two. Also, like the first sleeve 4, the second sleeve 7 has a guide portion 7 that widens in a tapered shape at the entrance thereof.
a, and the outer peripheral edge of this guide portion 7a is fixed to the downstream side of the merging port 3 by means such as welding.
Therefore, the second sleeve 7 forms within it a mixed flow section 10 that communicates with both the inner flow section 5 and the outer flow section 6 .

Next, the operation of the thermal shock prevention device will be explained. The fluid flowing from the upstream side of the main pipe 1 passes through the guide portion 4a and the inner flow portion 5 of the first sleeve 4, as shown by the solid arrow in FIG. On the other hand, other fluids having different temperatures flowing from the merging pipe 2 pass through the outer flow section 6 as shown by the dotted line arrows and pass through the guide section 7a.
It enters the flow gap 8 from there. These two types of fluids with different temperatures pass through the first sleeve 4 during the flow.
, and flows into the mixing flow section 10 in a state where the temperature difference between them is alleviated to some extent. A heat shielding gap 9 is formed on the outside of the second sleeve 1 to prevent heat from the mixed flow section 10 from being directly transmitted to the main pipe 1. Both fluids meet in this mixing flow section 10, mix, and exit to the main pipe 1.

In this way, according to the thermal shock prevention device, the first
The fluid flowing out from the sleeve 4 is sufficiently mixed in the mixing flow section 10 without directly touching the main pipe 1, and after the temperature is made uniform, the fluid flows into the main pipe 1. Therefore, thermal fluctuations occurring in the mixing region of both fluids can be prevented from acting on the main pipe 1, and thermal shock can be prevented from occurring in the main pipe 1.

In short, this invention can be applied to a confluence section of fluids with a temperature difference, so it goes without saying that it can be applied not only to nuclear equipment but also to other general equipment and equipment.

As explained above, in this invention, a second sleeve is provided on the downstream side of the first sleeve, and fluids having a temperature difference are exchanged with each other via the first sleeve to alleviate the temperature difference. Both fluids are mixed in the mixing flow section in the second sleeve and flowed out into the main pipe, so that fluids with different temperatures can be maintained at a stable and uniform temperature without directly touching the inner surface of the pipe. It can be made to flow out. Therefore, thermal stress fluctuations occurring in the mixing region can be suppressed, which is extremely effective in preventing thermal shock and protecting structural materials such as pipes. Therefore, even in cases where structural materials are required to have strict durability, such as in nuclear power generation facilities, a sufficient thermal shock prevention effect can be exhibited, and the soundness of the facility can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a conventional thermal shock prevention device, and FIG. 2 is a vertical sectional view of a thermal shock prevention device showing an embodiment of this invention. 1... Main pipe, 2... Merging pipe, 3... Merging port, 4
...First sleeve, 4a...Guiding part, 5...Inner circulation part, 6...Outer circulation part, 7...Second sleeve, 9...Heat shield gap, 10...Mixing circulation part.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) It has an inner circulation part that is disposed inside the confluence port of the confluence pipe connected in the middle of the main pipe and allows the fluid flowing through the main pipe to pass therethrough, and has the above-mentioned merging fluid between the inner surface of the main pipe and A first sleeve forming an outer circulation section through which fluid flows through the pipe, and a mixed circulation section disposed downstream of the first sleeve and communicating with both the inner circulation section and the outer circulation section are provided inside. and a second pipe having a heat shielding gap between the main pipe and the inner surface of the main pipe.
A thermal shock prevention device for a pipe connection, characterized by comprising a sleeve. (2) The scope of the utility model registration claim, characterized in that the first sleeve and the second sleeve each have a guide portion that tapers toward the inlet side, and the guide portion is fixed to the inner surface of the main pipe. The thermal shock prevention device for a pipe connection part according to item 1.