JPH048398Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drain valve, and more particularly to a drain valve attached to a cask for transporting radioactive materials.

Figure 1 shows a schematic cross section of the cask 1.
The cask body 2 is made of a shielding material such as lead, and has a storage chamber 3 in which radioactive materials are stored.
is formed. When storing radioactive substances in the storage chamber 3, the storage chamber 3 is also filled with water. A drain valve 4 is attached to the lower part of the cask body 2 to drain water from the storage chamber 3 during cask cleaning. By the way, conventionally, the drain valve 4 shown in FIG. 2 has been used. That is, the outer peripheral side wall portion 2 of the cask body 2
A catch seat 5 is fixed to the catch seat 5, and a mounting block 6 is attached to the catch seat 5 by, for example, bolts. A flow path 8 whose end opens on the surface of the mounting block 6 is formed, and a valve body 9 for opening and closing the flow path 8 is formed in the center of the mounting block 6.
and a valve rod 10 for moving the valve body 9. By the way, since the operating part of the valve stem 10 protrudes from the surface of the mounting block 6, there is a risk of damage, and a bellows 11 is interposed between the valve stem 10 and the valve body 9, and this part Since a large space is created and the operating handle 12 is provided at the end of the valve stem 10, a large space is created between the mounting block 6 and the protective cover 13, and these spaces reduce the radiation shielding ability. The disadvantage was that it decreased.

Therefore, an object of the present invention is to provide a drain valve that can eliminate the above-mentioned drawbacks.

That is, in the present invention, a recess is formed on the outer periphery of the cask body, a step is formed on the periphery of the opening of the recess, and
Connecting a communication pipe from a radioactive material storage chamber formed inside the cask body to the bottom of the recess, providing a removable block body in the recess, and forming a valve chamber inside the block body, A first flow path that communicates between the valve chamber and the communication pipe and a second flow path that communicates between the valve chamber and the outer surface of the block body are formed, the tip of which is located within the storage chamber and communicates with the first flow path. A valve body whose opening can be freely opened and closed is provided on the block body, an O-ring is installed between the valve body and the block body, and the length of the valve body is such that the communication opening of the first flow path is closed. The length and shape are such that the rear end surface does not protrude from the outer surface of the block body when
Further, when the block body is installed in the recess, a protective cover for protecting the block body is removably provided on the stepped portion at the periphery of the recess, and the thickness of the protective cover is adjusted so that the outer surface of the block body is The cask is characterized by a thickness that does not protrude from the outer surface of the cask body.

An embodiment of the present invention will be described below with reference to FIG. 21 is a recess with a circular cross section formed on the outer periphery of the cask body 22 at a predetermined location;
An annular step 23 is formed around the opening of the cask, and a drain communication pipe 24 from a radioactive substance storage chamber (not shown) formed inside the cask body 22 is connected to the bottom of the recess 21. ing. Reference numeral 25 denotes a cylindrical block having approximately the same size as the recess 21, and is removably attached to the bottom of the recess 21 with a plurality of bolts 26. and,
A valve chamber 27 is formed inside the block body 25, and a first flow passage 28 that communicates the valve chamber 27 with the communication pipe 24 and the valve chamber 27 and the block body 2 are provided.
A second flow path 29 is formed which communicates with the outer surface of 5. 30 is a valve body inserted into a hole 31 formed in the center of the block body 25, and its tip 30
a is located within the valve chamber 27 and is configured to open and close the communication opening of the first flow path 28 .

That is, the rear end 30b of the valve body 30 is the distal end 30a.
It is made larger and has a male thread formed on its outer periphery, and a female thread is formed in the upper part of the hole 31 of the block body 25 to be screwed into the male thread.
Therefore, by rotating the valve body 30, the first
The communication opening of the flow path 28 can be opened and closed.
The length of the valve body 30 is such that the rear end surface does not protrude from the outer surface of the block body 25 when the communication opening of the first flow path 28 is closed. Note that 32 is a drain plug screwed onto the open end of the second flow path 29. Reference numeral 33 denotes an O-ring 34A, 3, which has one end open to the outer surface of the block body 25 and the other end to the bottom surface of the block body, and is doubly attached around the first flow path 28.
This is a leak test hole opened between 4B and used to check for leakage of contaminated water. In addition, 3
5 is a plug screwed into the opening on the outer surface side of the leak test hole 33. Further, the valve body 30, drain plug 32 and plug 35 are connected to the block body 25.
Since it is installed at a position inside from the outer surface, each head on the outer surface side has a hexagonal hole 3 for inserting a wrench.
6, 37, and 38 are formed. Additionally, O-rings 3 are provided on the contact surfaces of the valve body 30, drain plug 32, and plug 35 with the block body 25, respectively.
9, 40, and 41 are installed. And 42
is a protective cover that protects the block body 25 when the block body 25 is installed in the concave portion 21, and is attached to the stepped portion 23 at the periphery of the opening of the concave portion 21 with bolts 43. Further, the thickness of the protective cover 42 is such that the outer surface thereof does not protrude from the outer surface of the cask body 22 in the attached state. Note that a tip portion 30a is provided at a predetermined location on the outer periphery of the rear end portion 30b of the valve body 30.
A groove 44 is formed to notify a predetermined amount of movement.

In the above configuration, when draining contaminated water in the storage chamber of the cask body 22, first the protective cover 42 is drained.
Then, the drain plug 32 is removed and an external drain pipe (not shown) is connected to the second flow path 29. Then, by rotating the valve body 30 in a predetermined direction and loosening it until the mark groove 44 on the rear end portion 30b is visible, the contaminated water in the storage chamber can be discharged.

As shown in FIG. 4, the drain valve 51 can of course be applied to a large cask 53 having cooling fins 52 on its outer surface.

As described above, according to the drain valve of the present invention, the valve body and protective cover are provided inside the outer periphery of the cask body, so there is no risk of damage to the valve body as in the conventional case, and the valve body Since an O-ring is installed between the valve body and the block body, the number of parts needed to attach the valve body can be reduced compared to the conventional case of using bellows, making it possible to downsize the drain valve. Furthermore, there is almost no extra space between the valve body and the block body, and there is also no extra space between the cover that protects the valve body and the outer surface of the block body, so the radiation protection ability is reduced. It can be prevented.

[Brief explanation of the drawing]

Figures 1 and 2 show conventional examples.
The figure is an overall cross-sectional view, Figure 2 is an enlarged cross-sectional view of main parts, and Figure 3 is an enlarged cross-sectional view of main parts.
The figure is an enlarged sectional view of a main part of one embodiment of the present invention, and FIG. 4 is a partially cutaway overall side view of another embodiment. 21... recess, 22... cask body, 23...
...Stepped portion, 24...Communication pipe, 25...Block body,
27...Valve chamber, 28...First flow path, 29...Second
Channel, 30...valve body, 42...protective cover.

Claims (1)

[Scope of utility model registration request] A recess is formed on the outer periphery of the cask body, a step is formed at the opening periphery of the recess, and a communication pipe from a radioactive substance storage chamber formed inside the cask body is connected to the bottom of the recess, and the recess is A removable block body is provided inside the block body, and a valve chamber is formed inside the block body, and a first flow passage communicates the valve chamber with the communication pipe, and a first passage communicates the valve chamber with the outer surface of the block body. The block body is provided with a valve body that forms two flow passages, the tip of which is located within the valve chamber, and which can freely open and close the communication opening of the first flow passage, and an O-ring is placed between the valve body and the block body. The length of the valve body is such that the rear end surface does not protrude from the outer surface of the block body when the communication opening of the first flow path is closed, and the block body has a concave portion. A protective cover that protects the block body when it is installed inside the cask body is removably provided on the stepped part of the periphery of the recess. A drain valve characterized by its thickness so that it does not protrude.