Refrigeration – Refrigerant or coolant – storer or handler – Envelope type
Reexamination Certificate
1999-11-22
2001-06-12
Doerrler, William (Department: 3744)
Refrigeration
Refrigerant or coolant, storer or handler
Envelope type
C062S045100
Reexamination Certificate
active
06244068
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
The present invention relates to a vacuum adiabatic type coolant container for holding low temperature coolants such as liquid nitrogen, liquid helium, or liquid hydrogen.
(ii) Description of Related Art
Japanese Patent Laid-Open Publication No. 57-195998 describes a conventional coolant container made of fiber reinforced plastics (hereinafter referred to as “FRP”). According to this document, the coolant container is made by joining together the cylinder which forms the inner surface of the container and the panel which forms the bottom surface. It also suggests the possibility of forming these as a single unit.
FIG. 4
is a cross section of an example of a conventional coolant container wherein the inner container comprising a cylinder and a panel are built inside the outer container formed as a single unit. A coolant container
30
in a substantially cylindrical shape is comprised of a cup-shaped, single-unit outer container
31
and an inner container
32
placed inside the outer container
31
. The inner container
32
is comprised of a panel
322
in a simple disk shape that engages with the lower end of a round cylinder
321
(the lower end as shown in
FIG. 4
; hereinafter “lower” and “upper” are used in relation to the figures). There is a flange on the upper end of the inner container
32
which fits the open end of the outer container
31
, and the space enclosed by the outer container
31
and the inner container
32
is maintained with a vacuum and forms a vacuum adiabatic portion
13
.
When a coolant
6
is held inside the inner container
32
of coolant container
30
constructed in this way, evaporation of the coolant
6
is restricted by the adiabatic effect of the vacuum adiabatic portion
13
, and as a result the coolant
6
can be maintained for a long period of time.
FIG. 5
is a cross section of an example of another conventional coolant container and shows the construction of the container disclosed in the above Laid-Open Patent. This coolant container
40
comprises a cylinder
321
in a simple, rounded-edge, cylindrical shape engaged with the inner surface of the upper end of a panel
402
formed in the shape of a short cup and bonded together.
However, the following problems arise with the conventional coolant container
30
.
1) When external pressure such as or approximately the same pressure with an atmospheric pressure acts on the upper surface of the panel
322
and the inner surface of the cylinder
321
of the inner container
32
shown in
FIG. 4
from toward the bottom), there is a danger that with the engagement configuration of the inner container
32
the panel
322
will sink down against the lower side of the vacuum adiabatic portion
13
and the coolant maintenance capability of the container will decline. If the vacuum is broken in this way, the adiabatic capability of the vacuum adiabatic portion
13
will be lost and the coolant can easily evaporate due to heat transfer from the outside. It is therefore necessary to reinforce the container by processing a internal thread on the inner periphery of the lower end of the round cylinder
321
and a external thread that fits the internal thread on the panel
322
, and fitting the external thread into the internal thread to prevent the panel
322
from sinking down. The same reinforcement as the inner container
32
will be necessary for the outer container
31
if it, like the inner container
32
, is cylindrical shape with an open lower end closed off with a disk-shaped panel, because external pressure such as approximately the same pressure with atmospheric pressure will act from below on this panel. Construction of the screw and nut is troublesome and because it is necessary to increase the thickness of the panel
322
in order to obtain a designated screw-mesh force, the cost of materials mounts.
Even when the inner container
40
of the engagement configuration shown in
FIG. 5
is used as the inner container
32
in the coolant container
30
, the danger that the panel
402
will sink down toward the vacuum adiabatic portion
13
side of the lower end and the capability of the container to maintain the coolant will decline cannot be ruled out.
2) If the cup-shaped outer container
31
as shown in
FIG. 4
is made of FRP for example, a mold is produced and the FRP layers are layered by hand one at a time on top of the mold while coating with a matrix resin to form a single-unit container (hand lay-up method). However, this manufacturing method is time-consuming and manufacturing costs are high. A method in which the FRP and resin are sprayed together onto the mold (spray-up method) can be applied, but again the manufacturing costs are high and there are limits to the shape of the mold.
SUMMARY OF THE INVENTION
The purpose of the present invention, considering the above problems, is to provide a low cost coolant container that is easily produced but has the required structural strength, without decreasing the capability of the container to maintain the coolant and a manufacturing method of the coolant container making production easy with a shortened production period and low production costs.
In order to solve the above problems, the coolant container of the present invention is constructed such that a hollow portion is formed by placing a substantially cylindrical inner container with one end closed up inside a substantially cylindrical outer container with one end closed up and joining both containers at the other end with coolant held inside the inner container, wherein either the outer container or the inner container or both has a cylindrical member and a plate member which engage at the peripheral end of the closed up end of the containers and the engaging portion of the peripheral end is formed either continuously or intermittedly around the periphery, and the structure includes a stopping means for stopping and supporting the peripheral ends of the plate members by resisting external force acting on the flat surface of the plate members.
With a coolant container constructed in this way, the plate member and the cylindrical member of either the outer container or the inner container or both engage at the peripheral end and if an external force such as a pushing force acts on the flat surface of the plate member the forces will be balance when a counteracting force of the same size as the external force and in the opposite direction works on the peripheral end of the plate member supported by the stopping means at the engaging portion resisting the external force. As a result, even if the container is not reinforced by fixing the plate member to the cylindrical member with a screw, the plate member can be prevented from sinking toward the hollow portion side between the outer container and the inner container. Also, because the cylindrical member and the plate member engage at a designated location on the peripheral end, when the container is assembled by engaging the plate member and the cylindrical member, the plate member will not slip in a planar direction and the container can be assembled while precisely positioning the plate member.
Further, if the above hollow portion is maintained in a vacuum and made a vacuum adiabatic portion, evaporation of the coolant held in the inner container can be restricted by the adiabatic effect of this vacuum adiabatic portion. At this time, an external pressure (substantially the same pressure with an atmospheric pressure) corresponding to the difference in atmospheric pressure in the inside and the outside of the vacuum adiabatic portion acts toward the vacuum adiabatic portion on the outer surface of the outer container and the inner surface of the inner container which form the boundaries of the vacuum adiabatic portion. The plate members of the inner container and the outer container upon which this pressure acts are prevented from sinking toward the vacuum adiabatic portion by the balancing of forces at the peripheral end due to the function of the stopping means described above.
Doerrler William
Foley & Lardner
Jiang Chen Wen
Sumitomo Electric Industries Ltd.
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