U.S. patent application number 14/698152 was filed with the patent office on 2016-08-11 for hydrogen liquefaction device.
The applicant listed for this patent is Korea Institute of Science and Technology, University of Central Florida Research Foundation. Invention is credited to Jong Hoon Baik, Sarng Woo Karng, SEO YOUNG KIM.
Application Number | 20160231049 14/698152 |
Document ID | / |
Family ID | 55309016 |
Filed Date | 2016-08-11 |
United States Patent
Application |
20160231049 |
Kind Code |
A1 |
Baik; Jong Hoon ; et
al. |
August 11, 2016 |
HYDROGEN LIQUEFACTION DEVICE
Abstract
An example hydrogen liquefaction apparatus is disclosed. The
apparatus includes an outer container; a liquefaction container
positioned at least partially within the outer container; a heat
pipe positioned within the liquefaction container. The head pipe
includes a condensing portion, an evaporating portion, an inner
tube portion containing a working fluid and operatively coupling
the condensing portion to the evaporating portion, and an outer
tube portion surrounding the inner tube portion and defining a dual
tube region between the outer tube and the inner tube. Also
included is a cryocooler in thermal communication with the
liquefaction container, a pre-cooling tube, and an ortho-para
converting part having a catalyst configured to induce an
ortho-para conversion of gaseous hydrogen within the pre-cooling
tube.
Inventors: |
Baik; Jong Hoon; (Orlando,
FL) ; Karng; Sarng Woo; (Seoul, KR) ; KIM; SEO
YOUNG; (SEOUL, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
University of Central Florida Research Foundation
Korea Institute of Science and Technology |
Orlando
Seoul |
FL |
US
KR |
|
|
Family ID: |
55309016 |
Appl. No.: |
14/698152 |
Filed: |
April 28, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25J 1/0276 20130101;
F25J 1/001 20130101; F28D 15/0233 20130101; F25J 2270/908 20130101;
F28D 15/06 20130101; F25J 1/0225 20130101 |
International
Class: |
F25J 1/00 20060101
F25J001/00; F25J 1/02 20060101 F25J001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 5, 2015 |
KR |
10-2015-0016990 |
Claims
1. A hydrogen liquefaction apparatus, comprising: an outer
container; a liquefaction container positioned at least partially
within the outer container; a heat pipe positioned within the
liquefaction container and comprising a condensing portion, an
evaporating portion, an inner tube portion containing a working
fluid and operatively coupling the condensing portion to the
evaporating portion, and an outer tube portion surrounding the
inner tube portion and defining a dual tube region between the
outer tube and the inner tube; a cryocooler in thermal
communication with the liquefaction container and configured to
cool the condensing portion of the heat pipe; a pre-cooling tube
positioned at least partially within the dual tube region and
comprising an inlet port for receiving gaseous hydrogen and an
outlet port for discharging gaseous hydrogen into the liquefaction
container; and an ortho-para converting part positioned at least
partially within the pre-cooling tube, the ortho-para converting
part comprising a catalyst configured to induce an ortho-para
conversion of gaseous hydrogen within the pre-cooling tube.
2. The hydrogen liquefaction apparatus of claim 1, comprising a
gaseous hydrogen transfer tube operatively connected to the inlet
port of the pre-cooling tube and configured to supply gaseous
hydrogen to the pre-cooling tube.
3. The hydrogen liquefaction apparatus of claim 1, comprising a
liquefaction guide tube operatively connected to the outlet port of
the pre-cooling tube and configured to transfer liquid hydrogen
from the pre-cooling tube to the liquefaction container.
4. The hydrogen liquefaction apparatus of claim 1, wherein the
pre-cooling tube is configured to pre-cool and ortho-para convert
gaseous hydrogen.
5. The hydrogen liquefaction apparatus of claim 1, wherein the
pre-cooling tube is configured to pre-cool the gaseous hydrogen to
an equilibrium state of about 77 degrees Kelvin.
6. The hydrogen liquefaction apparatus of claim 1, wherein the
evaporating portion causes the gaseous hydrogen to liquefy upon
contact.
7. The hydrogen liquefaction apparatus of claim 1, wherein the dual
tube region is at least partially filled with solid nitrogen.
8. The hydrogen liquefaction apparatus of claim 6, wherein the
solid nitrogen is formed via cooling of gaseous or liquid nitrogen
within the dual tube region.
9. The hydrogen liquefaction apparatus of claim 1, wherein the
outlet port is configured to expel gaseous hydrogen toward a
surface of the evaporating portion.
10. The hydrogen liquefaction apparatus of claim 1, wherein the
ortho-para converting part is provided along the entire pre-cooling
tube.
11. The hydrogen liquefaction apparatus of claim 1, wherein the
inlet port comprises a valve for controlling the transfer of
gaseous hydrogen.
12. The hydrogen liquefaction apparatus of claim 1, comprising a
liquid hydrogen transferring tube configured to transfer liquid
hydrogen from the liquefaction container.
13. The hydrogen liquefaction apparatus of claim 1, comprising a
nitrogen transferring tube configured to transfer gaseous or liquid
nitrogen into the dual tube region.
14. The hydrogen liquefaction apparatus of claim 1, wherein the
evaporating portion of the heat pipe is configured to maintain a
temperature of about 20 degrees Kelvin.
15. A method of liquefying hydrogen, comprising providing a
liquefaction container positioned at least partially within an
outer container; providing a heat pipe within the liquefaction
container, the heat pipe comprising a condensing portion, an
evaporating portion, an inner tube portion, and an outer tube
portion, wherein the inner and outer tube portions for a dual tube
region; introducing gaseous hydrogen into a pre-cooling tube
positioned within the dual tube region; ortho-para converting the
gaseous hydrogen within the pre-cooling tube; and collecting liquid
hydrogen within the liquefaction container.
16. The method of claim 15, comprising cooling a condensing portion
of the heat pipe via a cryocooler.
17. The method of claim 15, comprising filling at least a portion
of the dual tube region with solid nitrogen.
18. The method of claim 17, wherein filling further comprises
converting gaseous or liquid nitrogen into solid nitrogen within
the dual tube region.
19. The method of claim 15, comprising liquefying the gaseous
hydrogen upon thermal contact with the evaporating portion of the
heat pipe.
20. A heat pipe, comprising: a condensing portion; an evaporating
portion; an inner tube portion containing a working fluid and
operatively coupling the condensing portion to the evaporating
portion; an outer tube portion surrounding the inner tube portion
and defining a dual tube region between the outer tube and the
inner tube; a cryocooler in thermal communication with the
condensing portion; a pre-cooling tube positioned at least
partially within the dual tube region and comprising an inlet port
for receiving gaseous hydrogen and an outlet port for discharging
gaseous hydrogen into the liquefaction container; and an ortho-para
converting part positioned at least partially within the
pre-cooling tube, the ortho-para converting part comprising a
catalyst configured to induce an ortho-para conversion of gaseous
hydrogen within the pre-cooling tube.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2015-0016990, filed on Feb. 5,
2015, the disclosure of which is incorporated herein by reference
in its entirety.
BACKGROUND
[0002] The present disclosure relates to a hydrogen liquefaction
device, and more particularly, to a hydrogen liquefaction device
using a dual tube type heat pipe, which utilizes cooling energy of
a cryocooler via dual tube type heat pipe to liquefy gaseous
hydrogen. A method of liquefying hydrogen is also disclosed
herein.
[0003] Recently, hydrogen energy has emerged as a potential
solution to air pollution and climate change caused by excessive
use of fossil fuels. Utilizing fuel sources that are not
hydrocarbon based can help reverse the problems of pollution and
climate change that may otherwise continue unchecked. Hydrogen is
advantageous because it can be obtained from water. In addition,
unlike hydrocarbon fuels, when hydrogen energy is combusted it only
creates water as a byproduct. No carbon dioxide is emitted, for
example.
[0004] In order to effectively utilize hydrogen as energy source,
it should be made convenient to transport and store. These goals
may be achieved by, for example, reducing the volume of the
hydrogen via a densification process. Among the methods for
reducing a volume of hydrogen and storing hydrogen, a method of
liquefying and storing the hydrogen in a liquid phase has the
largest storage energy.
[0005] Among methods for liquefying gaseous hydrogen, the
Linde-Hampson cycle, Claude cycle, and similar cycles are known.
However, these liquefying cycles require large-scale hydrogen
liquefaction systems that may not be suitable for liquefying and/or
transporting smaller amounts of hydrogen. The ability to liquefy
and/or transport small amounts of hydrogen is an important aspect
of increasing hydrogen consumption in different sectors of the
global economy.
[0006] As a result, a need exists for improving the performance and
stability of hydrogen liquefaction processes. This is particularly
true for those processes employing a cryocooler.
SUMMARY
[0007] In one example embodiment, a hydrogen liquefaction apparatus
is disclosed. The apparatus includes an outer container; a
liquefaction container positioned at least partially within the
outer container; a heat pipe positioned within the liquefaction
container. The head pipe includes a condensing portion, an
evaporating portion, an inner tube portion containing a working
fluid and operatively coupling the condensing portion to the
evaporating portion, and an outer tube portion surrounding the
inner tube portion and defining a dual tube region between the
outer tube and the inner tube. Also included is a cryocooler in
thermal communication with the liquefaction container and
configured to cool the condensing portion of the heat pipe; a
pre-cooling tube positioned at least partially within the dual tube
region and comprising an inlet port for receiving gaseous hydrogen
and an outlet port for discharging gaseous hydrogen into the
liquefaction container; and an ortho-para converting part
positioned at least partially within the pre-cooling tube, the
ortho-para converting part comprising a catalyst configured to
induce an ortho-para conversion of gaseous hydrogen within the
pre-cooling tube.
[0008] In another example embodiment, a method of liquefying
hydrogen is disclosed. The method includes, for example, providing
a liquefaction container positioned at least partially within an
outer container, and providing a heat pipe within the liquefaction
container, the heat pipe including a condensing portion, an
evaporating portion, an inner tube portion, and an outer tube
portion, wherein the inner and outer tube portions for a dual tube
region. The method includes introducing gaseous hydrogen into a
pre-cooling tube positioned within the dual tube region; ortho-para
converting the gaseous hydrogen within the pre-cooling tube; and
collecting liquid hydrogen within the liquefaction container.
[0009] In yet another example embodiment, a heat pipe is disclosed
having a condensing portion; an evaporating portion; an inner tube
portion containing a working fluid and operatively coupling the
condensing portion to the evaporating portion; an outer tube
portion surrounding the inner tube portion and defining a dual tube
region between the outer tube and the inner tube; a cryocooler in
thermal communication with the condensing portion; a pre-cooling
tube positioned at least partially within the dual tube region and
comprising an inlet port for receiving gaseous hydrogen and an
outlet port for discharging gaseous hydrogen into the liquefaction
container; and an ortho-para converting part positioned at least
partially within the pre-cooling tube, the ortho-para converting
part comprising a catalyst configured to induce an ortho-para
conversion of gaseous hydrogen within the pre-cooling tube.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other objects, features, and advantages of the
present invention will become more apparent to those of ordinary
skill in the art by describing in detail exemplary embodiments
thereof with reference to the accompanying drawings, in which:
[0011] FIG. 1 is a diagrammatic view showing an example structure
of a hydrogen liquefaction apparatus using a dual tube type heat
pipe.
[0012] FIG. 2 is a diagrammatic view of an example structure of a
dual tube region of a heat pipe in a hydrogen liquefaction
apparatus using a dual tube type heat pipe.
DETAILED DESCRIPTION
[0013] Hydrogen liquefaction device and methods of liquefying
hydrogen are disclosed herein. In some example embodiments, the
hydrogen liquefaction device utilizes a dual tube type heat pipe as
described in detail below with reference to the accompanying
drawings. While the present disclosure is shown and described in
connection with example embodiments, various modifications can be
made without departing from the spirit and scope of the
invention.
[0014] FIG. 1 a diagrammatic view showing an example structure of a
hydrogen liquefaction apparatus using a dual tube type heat pipe
and FIG. 2 is a diagrammatic view of an example structure of a dual
tube region of a heat pipe in a hydrogen liquefaction apparatus
using a dual tube type heat pipe.
[0015] Referring to FIGS. 1 and 2, an example embodiment of a
hydrogen liquefaction apparatus is depicted. The hydrogen
liquefaction apparatus utilizes a dual tube type heat pipe design.
The device may include, for example, an external container 10, a
liquefaction container 20, a cryocooler 30, a heat pipe 40, a
pre-cooling tube 50, and an ortho-para converting part 51.
[0016] The external container 10 is configured to contain the
liquefaction container 20, heat pipe 40, pre-cooling tube 50, and
ortho-para converting part 51. The external container 10 may take
any form, but as shown in FIG. 1 has a cylindrical shape with an
open upper end to enable another element such as the liquefaction
container 20 and the like to be received therein. The open upper
end of the external container 10 may be hermetically covered with
an upper cover 12.
[0017] A cryocooler 30 may be installed on the upper cover 12 or on
the external container 10 directly. Cryocooler 30 may be a
standalone cooler, such as, for example, a Stirling-type cooler, a
Gifford-McMahon-type cooler, a pulse-tube refrigerator, or a
Joule-Thomson-type cooler. Any other suitable type of cooler may be
used, and the disclosure herein is not intended to be limited to a
particular type of cryocooler. Cryocooler 30 may supply cooling
energy to the heat pipe 40 placed in the liquefaction container 20.
The cryocooler 30 may supply the cooling energy which is sufficient
to cool the liquefaction container 20 to a temperature of 20K or
less.
[0018] A heat insulating layer 11 and/or a multi-layer insulating
material (not shown) may be included between the external container
10 and the liquefaction container 20 to reduce heat invasion
generated in the radial direction caused by the environment
external to the external container 10.
[0019] Additionally, the space between the external container 10
and the liquefaction container 20 may be provided in a vacuum state
to form the heat insulating layer 11. The heat insulating layer 11
performs a function of blocking convective heat transfer otherwise
caused by air as well as conductive heat transfer to/from the
external container 10. A multilayered heat insulating material
layer can be formed by overlapping the heat insulating material
surrounding the liquefaction container 20 and, for example,
performs the function of reducing heat radiation to/from the
liquefaction container 20 and the external container 10.
[0020] The liquefaction container 20 is a cylindrical container
provided in the external container 10, an upper end of the
liquefaction container is fixed to the upper cover 12 or to a
support (not shown) connecting a bottom surface of the external
container 10 and a bottom surface of the liquefaction container 20
to each other. In order to reduce heat invasion in the axial
direction from the upper cover 12, the liquefaction container 20
may be provided with a blocking layer formed therein or a heat
insulating layer disposed thereon and may be then fixed to the
upper cover 12. According to another embodiment, in addition, it is
possible to install the liquefaction container through a separate
support acting as a medium.
[0021] The heat pipe 40 may be positioned in the liquefaction
container 20 for receiving the extremely low temperature cooling
energy from the cryocooler 30. In the embodiments of FIGS. 1 and 2,
the heat pipe 40 includes a condensing part 41, an evaporating part
42, an outer tube 43, and an inner tube 44 provided between the
condensing part 41 and the evaporating part 42 in the form of a
dual tube.
[0022] The condensing part 41 of the heat pipe 40 is in contact
with the cryocooler 30 to transfer the cooling energy of the
cryocooler 30 to the evaporating part 42 of the heat pipe 42
through working fluid acting as a medium. The evaporating part 42
liquefies gaseous hydrogen, which flows into the liquefaction
container 20, with the cooling energy transferred from the
condensing part 41 by means of the working fluid. Cooling fins 41a
and 42a are provided in the condensing part 41 and the evaporating
part 42, respectively, to promote the heat transfer in the heat
pipe 40.
[0023] The outer tube 43 is spaced from the inner tube 44 and
surrounds the inner tube 44. As a result, a dual pipe region 45 is
formed in the space between the outer tube 43 and the inner tube
44. In some embodiments, the dual pipe region 45 is filled, at
least partially, with solid nitrogen. Solid nitrogen is a cooling
material. To obtain solid nitrogen, gaseous nitrogen flows into and
is cooled in this region so that the gaseous nitrogen is
phase-changed to solid nitrogen (SN2) to at least partially fill
this region.
[0024] The pre-cooling tube 50 is provided in the dual pipe region
45. The pre-cooling tube 50 is spaced apart from the outer tube 43
and the inner tube 44 in the dual pipe region 45, and is extended
and wound around the inner tube 44 in the form of a coil. The
pre-cooling tube 50 may be wound around the inner tube 44 in other
orientations as well, depending on the implementation. The
pre-cooling tube 50 is connected to the outer tube 43 via an upper
inlet port 52 and a lower outlet port 54. The upper inlet port 52
is connected to a gaseous hydrogen transferring tube 62 and the
lower outlet port 54 is connected to a liquefaction guide tube
55.
[0025] In the embodiments of FIGS. 1 and 2, the ortho-para
converting part 51 is provided with a catalyst causing an
ortho-para conversion is formed in the pre-cooling tube 50. The
ortho-para converting part 51 may be formed over an entire length
of the pre-cooling tube 50 or may be formed over only a part of the
pre-cooling tube. Due to the ortho-para converting part 51 formed
in the pre-cooling tube 50, when gaseous hydrogen passes through
the pre-cooling tube 50, gaseous hydrogen is simultaneously
subjected to a pre-cooling and the ortho-para conversion.
[0026] The liquefaction guide tube 55 is extended toward an outer
surface of the evaporating part 42 of the heat pipe 40 to guide
gaseous hydrogen GH2 discharged through the liquefaction guide tube
55 to the evaporating part 42 of the heat pipe 40. The orientation
of liquefaction guide tube 55 shown in FIG. 1 is merely an example
orientation. Any orientation may be used to guide gaseous hydrogen
to the evaporating part 42 of the heat pipe 40.
[0027] A cooling material entering port 46 is formed on the outer
tube 43 for allowing gaseous nitrogen to flow into the dual pipe
region 45 between the outer tube 43 and the inner tube 44. The
cooling material entering port 46 is connected to a gaseous
nitrogen transferring tube 64. Gaseous nitrogen entered into the
dual pipe region 45 is cooled and then phase-changed to solid
nitrogen SN2, and the dual pipe region is at least partially filled
with solid nitrogen. In some embodiments the dual pipe region is
partially filled with solid nitrogen. In other embodiments the dual
pipe region is fully filled with solid nitrogen. In yet other
embodiments the dual pipe region is filled with a combination of
solid, liquid, and/or gaseous nitrogen.
[0028] The inner tube 44 of the heat pipe 40 is filled with gaseous
hydrogen acting as working fluid. For achieving the above, the heat
pipe 40 may be provided with a working fluid entering passage for
enabling gaseous hydrogen, which is the working fluid, to fill an
inner space of the inner tube 44 or may be manufactured such that
an inner space of the inner tube is hermetically filled with
working fluid.
[0029] The gaseous hydrogen transferring tube 62 for transferring
gaseous hydrogen from the outside to the liquefaction container 20
and the gaseous nitrogen transferring tube 64 for transferring
gaseous nitrogen are extended in the liquefaction container 20.
[0030] The gaseous hydrogen transferring tube 62 is connected to
the upper inlet port 52 of the pre-cooling tube 50 and the gaseous
nitrogen transferring tube 64 is connected to the cooling material
entering port 46 to supply gaseous nitrogen to the dual tube region
45 between the outer tube 43 and the inner tube 44.
[0031] Valves (not shown) may be installed on the gaseous hydrogen
transferring tube 62 and the gaseous nitrogen transferring tube 64
for controlling transferring of gaseous hydrogen and gaseous
nitrogen to the upper inlet port 52 and the cooling material
entering port 46.
[0032] Meanwhile, a liquid hydrogen transferring tube 68 is
connected to a bottom surface of the liquefaction container 20 for
transferring liquid hydrogen, which is liquefied in the
liquefaction container 20, to the outside.
[0033] An example process for liquefying hydrogen performed by, for
example, the device of FIGS. 1 and 2, is described herein.
[0034] In the initial stage of operating the hydrogen liquefaction
apparatus, the cooling energy is transferred from the cryocooler 30
to the condensing part 41 of the heat pipe 40. Some of gaseous
hydrogen transferred through the gaseous hydrogen transferring tube
62 is supplied to an inside of the inner tube 44 of the heat pipe
40 via a working fluid entering passage 48. Gaseous hydrogen
supplied to an inside of the inner tube 44 and acting as working
fluid flows upward and downward in the heat pipe 40 and transfers
the cooling energy of the cryocooler 30, which was transferred to
the condensing part 41, to the evaporating part 42.
[0035] Meanwhile, gaseous nitrogen transferred through the gaseous
nitrogen transferring tube 64 is supplied to the dual pipe region
45 between the outer tube 43 and the inner tube 44 through the
cooling material entering port 46. Gaseous nitrogen entered into
the dual pipe region 45 receives the cooling energy and is then
phase-changed to solid nitrogen.
[0036] Gaseous hydrogen transferred through the gaseous hydrogen
transferring tube 62 flows into the pre-cooling pipe 50 via the
upper inlet port 52. A time at which gaseous hydrogen flows into
the pre-cooling tube 50 may be controlled by controlling a valve.
While moving along the pre-cooling tube 50, gaseous hydrogen
entered into the pre-cooling pipe 50 is heat-exchanged with ambient
solid nitrogen and then pre-cooled. Simultaneously, gaseous
hydrogen passes through the ortho-para converting part 51, is in
contact with the ortho-para catalyst, and is converted to para
hydrogen, which is an equilibrium state corresponding to
approximately 77K, by performing the ortho-para conversion. Gaseous
hydrogen is subsequently transferred to the liquefaction guide tube
55 through the lower outlet port 54, and the liquefaction guide
tube 55 guides gaseous hydrogen toward the evaporating part 42 of
the heat pipe. Since gaseous hydrogen is in contact with the
evaporating part 42 of the heat pipe after pre-cooled and converted
to para hydrogen, gaseous hydrogen is rapidly liquefied to form a
liquid hydrogen drop.
[0037] Liquid hydrogen obtained by a contact between gaseous
hydrogen and the evaporating part 42 is fallen by its weight and is
collected to a lower portion of the liquefaction container 20, and
the liquid hydrogen collected in the lower portion of the
liquefaction container 20 is discharged to the outside through the
liquid hydrogen transferring tube 68.
[0038] As described above, according to the present invention,
while passing through the dual tube region 45 filled with solid
nitrogen via the pre-cooling tube 50, gaseous hydrogen is
heat-exchanged and passes the ortho-para catalyst so that gaseous
hydrogen is pre-cooled and ortho-para converted, and is then in
contact with the evaporating part 42 and is liquefied. As a result,
gaseous hydrogen of room temperature of 300K is in direct contact
with the cryocooler 30 to prevent a thermal load of the cryocooler
from being rapid increased. In other words, the present invention
is advantageous in that an initial thermal load of the cryocooler
can be reduced.
[0039] In addition, even when an operation of the cryocooler 30 is
halted, it is possible to retard the boil-off state in which liquid
hydrogen in the liquefaction container 20 is gradually evaporated
by a heat invasion from the outside until solid nitrogen with which
the dual tube region 45 of the heat pipe 40 is filled is
phase-changed to liquid nitrogen.
[0040] In some embodiments, the heat pipe and the ortho-para
converting part are combined into one unit.
[0041] According to one embodiment, while passing through the
pre-cooling tube placed in the dual tube region of the heat pipe,
which is filled with solid nitrogen, and the ortho-para converting
part, gaseous hydrogen is pre-cooled and ortho-para converted. For
example, gaseous hydrogen is pre-cooled to a temperature of 77K and
is ortho-para converted to an equilibrium state of 77K. Then,
gaseous hydrogen is in contact with the evaporating part of the
heat pipe and is liquefied to form liquid hydrogen. Due to the
above, gaseous hydrogen having a temperature of 300K is in direct
contact with the evaporating part of the heat pipe having a
temperature of 20K to prevent a load of the refrigerator from being
rapidly increased. As a result, an initial thermal load of the
refrigerator can be reduced.
[0042] According to another embodiment, in the state where an
operation of the cryocooler is halted, an evaporation of liquid
hydrogen is retarded for the time during which solid nitrogen is
phased-changed to liquid nitrogen. Thus, it is possible to enhance
the liquid hydrogen storage performance of the hydrogen
liquefaction apparatus.
[0043] It will be apparent to those skilled in the art that various
modifications can be made to the above-described exemplary
embodiments of the present disclosure without departing from the
spirit or scope of the invention. Thus, it is intended that the
present disclosure covers all such modifications provided they come
within the scope of the appended claims and their equivalents.
* * * * *