U.S. patent application number 13/832601 was filed with the patent office on 2013-12-19 for fluid pumping device, fuel cell device and fuel gas recirculation method using the same.
This patent application is currently assigned to KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. The applicant listed for this patent is KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY. Invention is credited to Hyung Chul HAM, Jonghee HAN, Seong Ahn HONG, Yeong Cheon KIM, Yong Min KIM, Suk Woo NAM, Chang Won YOON, Sung Pil YOON.
Application Number | 20130336826 13/832601 |
Document ID | / |
Family ID | 49756080 |
Filed Date | 2013-12-19 |
United States Patent
Application |
20130336826 |
Kind Code |
A1 |
KIM; Yong Min ; et
al. |
December 19, 2013 |
FLUID PUMPING DEVICE, FUEL CELL DEVICE AND FUEL GAS RECIRCULATION
METHOD USING THE SAME
Abstract
Provided is a fluid pumping device, and more particularly, a
fluid pumping device capable of being used in fuel cell systems and
the like and spatially separating a fluid temporary storage unit
through which a fluid at high temperature passes from a pump,
thereby maintaining the durability of the pump, facilitating
replacement and management, and achieving a reduction in
weight.
Inventors: |
KIM; Yong Min; (Seoul,
KR) ; KIM; Yeong Cheon; (Seoul, KR) ; YOON;
Chang Won; (Seoul, KR) ; NAM; Suk Woo; (Seoul,
KR) ; HAN; Jonghee; (Seoul, KR) ; HONG; Seong
Ahn; (Seoul, KR) ; YOON; Sung Pil;
(Gyeonggi-do, KR) ; HAM; Hyung Chul; (Seoul,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY |
SEOUL |
|
KR |
|
|
Assignee: |
KOREA INSTITUTE OF SCIENCE AND
TECHNOLOGY
SEOUL
KR
|
Family ID: |
49756080 |
Appl. No.: |
13/832601 |
Filed: |
March 15, 2013 |
Current U.S.
Class: |
417/474 |
Current CPC
Class: |
F04B 43/02 20130101;
F04B 43/025 20130101 |
Class at
Publication: |
417/474 |
International
Class: |
F04B 43/02 20060101
F04B043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 14, 2012 |
KR |
10-2012-0063636 |
Claims
1. A fluid pumping device comprising: a fluid temporary storage
unit which temporarily stores and discharges a flow of a fluid; a
pump which is positioned to be separated from the fluid temporary
storage unit and repeats suction and discharge of a fluid pressure;
a connection tube which connects the fluid temporary storage unit
and the pump to each other to transmit the fluid pressure by the
pump; and first and second check valves which are respectively
positioned at a fluid inlet and a fluid outlet of the fluid
temporary storage unit and are repeatedly opened and closed in
response to the suction and the discharge of the fluid pressure by
the pump, wherein, when the first check valve is closed, the second
check valve is opened, and when the first check valve is opened,
the second check valve is closed.
2. The fluid pumping device according to claim 1, wherein the fluid
temporary storage unit is positioned inside a high-temperature
unit, and the pump is positioned outside the high-temperature
unit.
3. The fluid pumping device according to claim 1, wherein the
high-temperature unit includes a heat insulation material on a wall
surface.
4. The fluid pumping device according to claim 1, wherein the
connection tube is a flexible tube.
5. The fluid pumping device according to claim 1, wherein the
connection tube further includes a cooling device on the outer
surface of the connection tube.
6. The fluid pumping device according to claim 1, wherein the pump
is a diaphragm pump including: a motor; a connecting rod which
performs a reciprocating motion according to a rotating motion of
the motor; a diaphragm which performs a vertical motion according
to the reciprocating motion of the connecting rod; and a
compartment which repeats contraction and expansion according to
the vertical motion of the diaphragm, and wherein the discharge and
the suction of the fluid pressure are achieved by the contraction
and the expansion of the compartment.
7. The fluid pumping device according to claim 1, wherein the fluid
temporary storage unit further includes a thin partition at a
connection portion connected to the connection tube.
8. The fluid pumping device according to claim 1, wherein a
plurality of the fluid temporary storage units are arranged, and
the plurality of the fluid temporary storage units are connected to
the pump by a plurality of the connection tubes.
9. The fluid pumping device according to claim 8, wherein at least
one of the fluid temporary storage units among the plurality of the
fluid temporary storage units is positioned inside the
high-temperature unit, and at least one of the fluid temporary
storage units among the plurality of the fluid temporary storage
units is positioned outside the high-temperature unit.
10. The fluid pumping device according to claim 1, wherein the
connection tube further includes a control valve which controls an
amount of the fluid pumped to the fluid temporary storage unit by
controlling the fluid pressure transmitted to the fluid temporary
storage unit.
11. The fluid pumping device according to claim 1, wherein the
check valves are ball type check valves or plate type check
valves.
12. The fluid pumping device according to claim 1, wherein the
fluid is a high-temperature outlet gas at higher than or equal to
100.degree. C. discharged from an anode of a fuel cell.
13. The fluid pumping device according to claim 8, wherein the
fluid pumping device includes first and second fluid temporary
storage units and first and second connection tubes, wherein a
diaphragm pump includes: first and second connecting rods connected
to a motor; a first diaphragm which is attached to one side of the
first connecting rod and performs a vertical motion according to a
reciprocating motion of the connecting rod; a second diaphragm
which is attached to one side of the second connecting rod and
performs a vertical motion according to a reciprocating motion of
the connecting rod; a first compartment which repeats contraction
and expansion according to the vertical motion of the first
diaphragm; and a second compartment which repeats contraction and
expansion according to the vertical motion of the second diaphragm,
wherein, when the first compartment contracts, the second
compartment expands, and when the first compartment expands, the
second compartment contracts, wherein the first compartment is
connected to the first fluid temporary storage unit by the first
connection tube, and wherein the second compartment is connected to
the second fluid temporary storage unit by the second connection
tube.
14. The fluid pumping device according to claim 13, wherein the
first and second fluid temporary storage units further include thin
partitions at connection portions connected to the first and second
connection tubes, respectively.
15. The fluid pumping device according to claim 1, wherein the
fluid pumping device includes a first fluid temporary storage unit
and a second fluid temporary storage unit, wherein the first fluid
temporary storage unit is positioned outside a high-temperature
unit, and the second fluid temporary storage unit is positioned
inside the high-temperature unit, and wherein the connection tube
connects the pump to the first fluid temporary storage unit and is
drawn therefrom to be connected to the second fluid temporary
storage unit.
16. The fluid pumping device according to claim 15, wherein the
connection tube between the first fluid temporary storage unit and
the second fluid temporary storage unit further includes a control
valve which controls the fluid pressure supplied from the first
fluid temporary storage unit to the second fluid temporary storage
unit.
17. The fluid pumping device according to claim 8, wherein the
fluid pumping device includes a first fluid temporary storage unit
and second to fourth fluid temporary storage units, wherein the
first fluid temporary storage unit is positioned outside a
high-temperature unit, and the second to fourth fluid temporary
storage units are positioned inside the high-temperature unit, and
wherein the connection tube connects the pump to the first fluid
temporary storage unit and is drawn therefrom to branch off to
three tubes so as to be connected to the second to fourth fluid
temporary storage units.
18. The fluid pumping device according to claim 17, wherein each of
the connection tubes between the first fluid temporary storage unit
and the second to fourth fluid temporary storage units further
includes a control valve which controls the fluid pressure supplied
from the first fluid temporary storage unit to the second to fourth
fluid temporary storage units.
19. A fuel cell device comprising: a fuel cell; and the fluid
pumping device according to claim 1, wherein an outlet gas
discharged from an anode of the fuel cell is supplied to the fluid
temporary storage unit.
20. A fuel gas recirculation method comprising: supplying an outlet
gas discharged from an anode of a fuel cell to the fluid temporary
storage unit of the fluid pumping device according to claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent
Application No. 10-2012-0063636, filed on Jun. 14, 2012, and all
the benefits accruing therefrom under 35 U.S.C. .sctn.119, the
contents of which in its entirety are herein incorporated by
reference.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure relates to a fluid pumping device,
and a fuel cell device and a fuel gas recirculation method using
the same, and more particularly, to a fluid pumping device capable
of being applied to a fuel cell device, particularly, a
high-temperature fuel cell and to a fluid mixing process under
high-temperature conditions, a cooling process, a reaction process,
a process of reaction between a solid and a fluid and extraction
under high-temperature conditions, a nuclear reactor, and the like,
and a fuel cell device and a fuel gas recirculation method using
the same.
[0004] 2. Description of the Related Art
[0005] There is an urgent request for energy efficiency due to
fossil energy depletion and environmental pollution.
[0006] Regarding this, in cases of high-temperature fuel cell
systems such as solid oxide fuel cells (SOFC) or molten carbonate
fuel cells, thermodynamic efficiency of power generation is high,
and waste heat at a high temperature has a wide range of
applications. Therefore, the systems have been actively
studied.
[0007] Particularly, such fuel cells are high-temperature fuel
cells that operate at a temperature of higher than or equal to
500.degree. C. and thus may use various hydrocarbons other than
hydrogen as fuels and may use inexpensive non-metallic
electrodes.
[0008] In the high-temperature fuel cell energy systems such as
solid oxide fuel cells and molten carbonate fuel cells, researches
for increasing energy efficiency have been carried out.
[0009] In detail, the fuel utilization (used fuel/supplied fuel) in
the fuel cell system is generally less than 100%. Therefore, the
unused fuel remains in gas discharged from the anode outlet. When
the fuel is recirculated by a pump and is supplied to the anode
inlet, the fuel utilization may be enhanced and thus the efficiency
of the fuel cell systems may be enhanced.
[0010] In addition, when the space velocity of the gas in the anode
is increased due to the recirculation of the gas discharged from
the anode outlet, the temperature distribution in the fuel cell may
become uniform, and mass transfer inside of the anode may be
improved, thereby simultaneously enhancing the performance and the
stability of the fuel cell stacks.
[0011] However, the temperature of the gas discharged from the
outlet of the high-temperature fuel cell is generally higher than
or equal to 500.degree. C. and such high-temperature gas has too
high temperature to be used in the recirculation pump. Therefore,
the temperature of the gas discharged from the outlet has to be
reduced to a temperature level that is able to be used in the
recirculation pump for fuel recirculation, and the temperature has
to be increased again to be supplied to the inlet of the fuel cell.
Therefore, there is a problem in that additional power for cooling
and heating is needed.
[0012] In the fluid pumping device for recirculation of the outlet
gas of the existing high-temperature fuel cell, a pump in a
low-temperature side and a fluid storage unit in a high-temperature
side are directly connected to each other to directly supply a
fluid at high temperature to the pump. Accordingly, in cases where
the fluid at high temperature is combustible and fluidic, a sealant
should be employed in the pump in order to maintain high
sealability of the pump, and a cooling device is installed on the
pump shaft for protecting the pump from being overheated by the
high-temperature fluid.
[0013] However, according to the research results of the inventors,
in cases where the temperature of a high-temperature unit in the
existing pumping device is increased, the length of the pump shaft
is increased. As a result, thermal deformation and vibration become
severe and this may result in degradation of the durability of the
pump. In addition, when the pump shaft is increased, there is a
problem in that the size of the pumping device itself is
increased.
REFERENCES OF THE RELATED ART
Patent Document
[0014] (Patent Document 1) Apparatus for cooling hydrogen
recirculation blower for fuel cell vehicle (US 2009/001419 A1)
[0015] (Patent Document 2) Foil gas bearing supported high
temperature centrifugal blower and method for cooling thereof (US
2009/0087299)
[0016] (Patent Document 3) Circulating pump (U.S. Pat. No.
3,478,689)
[0017] (Patent Document 4) High-temperature fan (U.S. Pat. No.
2,428,765)
[0018] (Patent Document 5) Pumping a high or low temperature fluid
(U.S. Pat. No. 3,666,375)
SUMMARY
[0019] The present disclosure is directed to providing a fluid
pumping device capable of being applied to a fuel cell device,
particularly, a high-temperature fuel cell and to a fluid mixing
process under high-temperature conditions, a cooling process, a
reaction process, a process of reaction between a solid and a fluid
and extraction under high-temperature conditions, a nuclear
reactor, and the like for recirculation of a fuel gas, thereby
maintaining the durability of a pump, facilitating replacement and
management, and achieving a reduction in weight and size, and a
fuel cell device and a fuel gas recirculation method using the
same.
[0020] In one aspect, there is provided a fluid pumping device
including: a fluid temporary storage unit which temporarily stores
and discharges a flow of a fluid; a pump which is positioned to be
separated from the fluid temporary storage unit and repeats suction
and discharge of a fluid pressure; a connection tube which connects
the fluid temporary storage unit and the pump to each other to
transmit the fluid pressure by the pump; and first and second check
valves which are respectively positioned at both inlet and outlet
of the fluid temporary storage unit and are repeatedly opened and
closed in response to the suction and the discharge of the fluid
pressure by the pump, wherein, when the first check valve is
closed, the second check valve is opened. Consequently, when the
first check valve is opened, the second check valve is closed.
[0021] According to an embodiment, the fluid temporary storage unit
may be positioned inside a high-temperature unit, and the pump may
be positioned outside the high-temperature unit.
[0022] According to an embodiment, the high-temperature unit may
include a heat insulation material on a wall surface.
[0023] According to an embodiment, the connection tube may be a
flexible tube.
[0024] According to an embodiment, the connection tube may further
include a cooling device.
[0025] According to an embodiment, the pump may be a diaphragm pump
including: a motor; a connecting rod which performs a reciprocating
motion according to a rotating motion of the motor; a diaphragm
which is attached to one side of the connecting rod and performs a
vertical motion according to the reciprocating motion of the
connecting rod; and a compartment which repeats contraction and
expansion according to the vertical motion of the diaphragm, and
the discharge and the suction of the fluid pressure may be induced
by the contraction and the expansion of the compartment.
[0026] According to an embodiment, the fluid temporary storage unit
may further include a thin partition installed at a connection
portion connected to the connection tube.
[0027] According to an embodiment, a plurality of the fluid
temporary storage units may be arranged, and the plurality of the
fluid temporary storage units may be connected to the pump by a
plurality of the connection tubes.
[0028] According to an embodiment, the plurality of the fluid
temporary storage units may be provided, at least one of the fluid
temporary storage units may be positioned inside the
high-temperature unit, and at least one of the fluid temporary
storage units may be positioned outside the high-temperature
unit.
[0029] According to an embodiment, the connection tube may further
include a control valve which controls a flow rate of the fluid
pumped to the fluid temporary storage unit.
[0030] According to an embodiment, the check valves may be ball
type check valves or plate type check valves.
[0031] According to an embodiment, the fluid may be a
high-temperature outlet gas at higher than or equal to 100.degree.
C. discharged from an anode of a fuel cell.
[0032] According to an embodiment, the fluid pumping device may
include first and second fluid temporary storage units and first
and second connection tubes. The diaphragm pump may include: first
and second connecting rods connected to a motor; a first diaphragm
which is attached to one side of the first connecting rod and
performs a vertical motion according to a reciprocating motion of
the connecting rod; a second diaphragm which is attached to one
side of the second connecting rod and performs a vertical motion
according to a reciprocating motion of the connecting rod; the
first compartment which repeats contraction and expansion according
to the vertical motion of the first diaphragm; and the second
compartment which repeats contraction and expansion according to
the vertical motion of the second diaphragm. When the first
compartment contracts, the second compartment may expand, and when
the first compartment expands, the second compartment may contract.
The first compartment may be connected to the first fluid temporary
storage unit by the first connection tube. The second compartment
may be connected to the second fluid temporary storage unit by the
second connection tube.
[0033] According to an embodiment, a thin partition may further be
installed at a connection portion between the first fluid temporary
storage unit and the first connection tube, and a thin partition
may further be installed at a connection portion between the second
fluid temporary storage unit and the second connection tube.
[0034] According to an embodiment, the fluid pumping device may
include a first fluid temporary storage unit and a second fluid
temporary storage unit, the first fluid temporary storage unit may
be positioned outside a high-temperature unit, and the second fluid
temporary storage unit is positioned inside the high-temperature
unit, and the connection tube may connect the pump to the first
fluid temporary storage unit and may be drawn therefrom to be
connected to the second fluid temporary storage unit.
[0035] According to an embodiment, a control valve which controls
the fluid pressure supplied from the first fluid temporary storage
unit to the second fluid temporary storage unit may further be
installed in the connection tube between the first fluid temporary
storage unit and the second fluid temporary storage unit.
[0036] According to an embodiment, the fluid pumping device may
include a first fluid temporary storage unit and second to fourth
fluid temporary storage units, the first fluid temporary storage
unit may be positioned outside a high-temperature unit and the
second to fourth fluid temporary storage units may be positioned
inside the high-temperature unit, and the connection tube may
connect the pump to the first fluid temporary storage unit and may
be drawn therefrom to branch off to three tubes so as to be
respectively connected to the second to fourth fluid temporary
storage units.
[0037] According to an embodiment, a control valve which controls
the fluid pressure supplied from the first fluid temporary storage
unit to the second to fourth fluid temporary storage units may be
installed in each of the connection tubes between the first fluid
temporary storage unit and the second to fourth fluid temporary
storage units.
[0038] In another aspect, there is provided a fuel cell device
including: a fuel cell; and the fluid pumping device, wherein an
outlet gas discharged from an anode of the fuel cell is supplied to
the fluid temporary storage unit.
[0039] In still another aspect, there is provided a fuel gas
recirculation method including: supplying an outlet gas discharged
from an anode of a fuel cell to the fluid temporary storage unit of
the fluid pumping device.
[0040] According to the aspects of the disclosure, compared to the
existing fluid pumping device, a high-temperature gas, for example,
the outlet gas at high temperature discharged from the anode of a
fuel cell may be used for pumping for recirculation without an
additional cooling process. In addition, the pump durability is
easily maintained, and factors of breakdown are reduced and thus
replacement and maintenance are easy, and a reduction in weight and
size is possible. Therefore, the device is simplified and there is
no limitation to installation locations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The above and other aspects, features and advantages of the
disclosed exemplary embodiments will be more apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0042] FIG. 1 is a conceptual diagram of a fluid pumping device
according to the disclosure;
[0043] FIG. 2 is a schematic diagram of a fluid pumping device
according to first embodiment of the disclosure;
[0044] FIG. 3 is a schematic diagram of a fluid pumping device (an
additional thin partition installed) according to second embodiment
of the disclosure;
[0045] FIG. 4 is a schematic diagram of a fluid pumping device
(double-acting type) according to third embodiment of the
disclosure;
[0046] FIG. 5 is a schematic diagram of a fluid pumping device
(double-acting type and an additional thin partition installed)
according to fourth embodiment of the disclosure;
[0047] FIG. 6 is a schematic diagram of a thin partition type fluid
pumping device including a control valve for a fuel cell according
to an embodiment of the disclosure;
[0048] FIG. 7 is a schematic diagram of a thin partition type
multiple fluid pumping device for a fuel cell according to an
embodiment of the disclosure;
[0049] FIG. 8 is a schematic diagram of a ball type check valve
according to an embodiment of the disclosure; and
[0050] FIG. 9 is a graph showing a result of pumping a
high-temperature gas using the fluid pumping device according to an
embodiment of the disclosure.
TABLE-US-00001 [Detailed Description of Main Elements] 10:
diaphragm pump 11: motor 12: connecting rod (12a: first connecting
rod, 12b: second connecting rod) 13: diaphragm (13a: first
diaphragm, 13b: second diaphragm) 14: compartment (14a: first
compartment, 14b: second compartment) 50: check valve (50a: first
check valve, 50b: second check valve) 20: connection tube (20a:
first connection tube, 20b: second connection tube) 30: heat
insulation material 33: high-temperature unit 40: fluid temporary
storage unit 40a: first fluid temporary storage unit 40b: second
fluid temporary storage unit 40c: third fluid temporary storage
unit 40d: fourth fluid temporary storage unit 60: thin partition
70: control valve 100: fluid pumping device
DETAILED DESCRIPTION
[0051] The present disclosure now will be described more fully
hereinafter with reference to the accompanying drawings. The
accompanying drawings show exemplary embodiments of the disclosure
and are provided only to facilitate understanding of the
disclosure. Therefore, the technical scope of the disclosure is not
limited by the drawings.
[0052] First, referring to FIG. 2, a fluid pumping device according
to an embodiment of the disclosure includes: a fluid temporary
storage unit which temporarily stores and discharges the flow of a
fluid; a pump which is positioned to be separated from the fluid
temporary storage unit and repeats suction and discharge of a fluid
pressure; a connection tube which connects the fluid temporary
storage unit and the pump to each other to transmit the fluid
pressure by the pump; and first and second check valves which are
respectively positioned at a fluid inlet and a fluid outlet of the
fluid temporary storage unit and are repeatedly opened and closed
in response to the suction and the discharge of the fluid pressure
by the pump. When the first check valve is closed, the second check
valve is opened, and when the first check valve is opened, the
second check valve is closed.
[0053] The fluid temporary storage unit is a unit which temporarily
stores and discharges the flow of the fluid, and although not
particularly limited, may have a form that minimizes an effect on
the flow of the fluid and has a volume at which an appropriate
fluid pressure is generated to cause a fluid flow according to a
use flow rate and a pressure. The material of the container is not
particularly limited as long as the material ensures a property of
being stable at high temperature (for example, mechanical
properties, thermal properties, and corrosion resistance). When the
material is a metal, a material may be selected from the group
consisting of stainless steel (Fe--Cr alloy), Inconel (Ni--Cr--Fe
alloy), and FeCrAlloy (Fe--Cr--Al alloy), and when the material is
a ceramic, a material may be selected from the group consisting of
zirconia, alumina, mulite, quartz (silica), and glass.
[0054] The fluid temporary storage unit is positioned to be
separated from the pump unlike the techniques according to the
related art. According to an embodiment, the container of the fluid
temporary storage unit is a part which temporarily stores and
discharges the fluid at high temperature and may be positioned
inside a high-temperature unit, and the pump may be positioned
outside the high-temperature unit.
[0055] The fluid temporary storage unit may further include a thin
partition at a connection portion connected to the connection tube.
Referring to FIG. 3, the fluid at high temperature may pass through
the fluid temporary storage unit, and when the fluid at high
temperature passing though the fluid temporary storage unit is
liquefied, there is a concern of the liquid escaping from the fluid
temporary storage unit and flowing into the connection tube. In the
case where the fluid at high temperature flows into the connection
tube, the fluid may flow into the pump though the connection tube,
resulting in damage in the durability of the pump. Therefore, by
positioning the thin partition between the fluid temporary storage
unit and the connection tube, the inflow of the fluid at high
temperature into the pump through a connection pipe may be
prevented beforehand. The thin partition is not limited as long as
the thin partition does not impede the fluid pressure transmitted
from the pump through the connection tube and blocks the inflow of
the fluid into the connection pipe.
[0056] In addition, in a case when the thin partition impedes the
transmission of the fluid pressure generated by the pump to the
fluid temporary storage unit, pumping of the fluid is not uniformly
performed, and there is a concern of a pumping efficiency being
reduced. Therefore, the thin partition may be detachable.
[0057] The check valves are connected to the fluid inlet and the
fluid outlet of the fluid temporary storage unit. The check valves
are not limited as long as the check valves are positioned at the
fluid inlet and the fluid outlet of the fluid temporary storage
unit and cause the fluid to flow only in one direction. The check
valves may be ball type check valves or plate type check valves. In
the case of the ball type check valves, the material of a ball may
be selected from the group consisting of ceramic (zirconia or
silica), glass, and a plastic that is stable at high temperature
(for example, Teflon).
[0058] An embodiment of the ball type check valve is illustrated in
FIG. 8. Referring to FIG. 8, a pipe in which the ball is positioned
widens in diameter in a direction in which the fluid flows, and in
a case where the fluid flows in the arrow direction, the ball in
the check valve moves upward and the interval between the pipe and
the ball is increased, thereby allowing the fluid to flow. In a
case where the fluid flows in an opposite direction (reverse
direction) to the arrow, the ball moves downward and narrows the
interval between the pipe and the ball, thereby causing the fluid
not to flow. Accordingly, the check valves have functions of
causing the fluid to flow only in one direction and preventing the
backflow of the fluid.
[0059] The diameter of the ball type check valve may vary depending
on the flow rate and the use pressure. In addition, the size of the
ball used in the ball type check valve may be changed according to
the diameter of the check valve, and has an appropriate weight in
order to have a role of opening and closing gas at a particular use
flow rate. The weight of the ball is set to sufficiently open and
close gas at a particular use flow rate and has an appropriate Kv
value (Kv is a flow rate of water at 5 to 30.degree. C. that passes
when the differential pressure of a valve is 1 bar) so as not to
apply an excessive pressure on the valve and not to cause a high
energy loss due to the excessive pressure.
[0060] In addition, the check valve may be of a metal plate type.
In the case of the metal plate type check valve, the material
thereof may be at least one selected from the group consisting of
stainless steel (Fe--Cr alloy), Inconel (Ni--Cr--Fe alloy), and
FeCrAlloy (Fe--Cr--Al alloy). Here, in the case of the metal plate
type check valve, the pump operates at temperatures at which the
elasticity of a metal plate is maintained. The operation
temperature of the metal plate type check valve is desirable to be
appropriately below 200.degree. C., and during operation at a
higher temperature, there is a possibility of the metal plate
deviating from its elastic limit and being subjected to plastic
deformation.
[0061] The pump is not limited as long as the pump generates the
fluid pressure and a diaphragm pump is desirable. Unlike the
configuration of a diaphragm according to the related art in which
check valves are formed at inlet and outlet portions in a
compartment in the diaphragm pump and a fluid is transmitted
through the compartment, the diaphragm pump of this disclosure has
a configuration including: a motor that generates power; a
connecting rod that performs a reciprocating motion according to a
rotating motion of the motor; a diaphragm (thin partition) that
performs a vertical motion according to the reciprocating motion of
the connecting rod; and a compartment that repeats contraction and
expansion according to the vertical motion of the diaphragm.
Therefore, unlike the diaphragm according to the related art, the
fluid does not directly pass through the compartment of the
diaphragm. The diaphragm is a kind of thin partition, and a
plurality of diaphragms connected to a single diaphragm pump may be
provided. Therefore, a plurality of compartments may be provided
(see FIGS. 4 and 5). In a diaphragm pump that includes the
plurality of compartments divided by the plurality of diaphragms, a
motor generates force, the force is transmitted to a connecting
rod, and the connecting rod performs a reciprocating motion to
cause the first diaphragm and the second diaphragm to perform
vertical motions. Accordingly, when the first compartment expands,
the second compartment contracts, and when the first thin partition
plate contracts, the second compartment expands. The contraction
and the expansion of the compartments are alternately repeated at
predetermined time intervals. The fluid pressures generated in the
first compartment and the second compartment are transmitted to a
first fluid temporary storage unit and a second fluid temporary
storage unit through a first connection tube and a second
connection tube connected to the first compartment and the second
compartment, respectively. Accordingly, pumping of the fluid into
the first and second fluid temporary storage units may be
alternately performed, and in a case where the fluid pumping device
is applied to a fuel cell, the fluid may be continuously supplied
to the fuel cell and may also be supplied at a constant amount.
[0062] The connection tube is not limited as long as the connection
tube connects the pump and the fluid temporary storage unit to each
other and transmits the fluid pressure generated by the pump to the
fluid temporary storage unit, and may be a flexible tube. The
flexible tube may be a long and thin bellows made of stainless
steel, phosphor bronze, or aluminum, or a tube that has rubber,
nylon, polyvinyl chloride resin, or the like as a main material,
and may be reinforced by a surrounding copper mesh having
sufficient elasticity on the outer side for reinforcement. The
volume and the diameter of the connection tube may vary depending
on the flow rate and the pressure of the fluid that passes through
the fluid temporary storage unit.
[0063] A cooling device may further be included on the outer
surface of the connection tube. The cooling device is not limited
as long as the cooling device cools the fluid to reduce the
temperature thereof in a case where the fluid at high temperature
is liquefied by the fluid temporary storage unit that stores and
discharges the fluid at high temperature and flows out to the
connection pipe side. The cooling device may be an air cooling type
or a water cooling type. In addition, the cooling device may
surround the entire connection tube and include a temperature
measuring and detecting sensor to sufficiently cool the fluid. When
the cooling device is not provided, some of the high-temperature
gas could be liquefied at the vicinity of the pump, resulting in
corrosion of the diaphragm and reducing the durability of the
pump.
[0064] A control valve may be disposed on the connection pipe
(FIGS. 6 and 7). The control valve is not limited as long as the
control valve controls the fluid amount pumped to the fluid
temporary storage unit by controlling the fluid pressure generated
by the pump and transmitted to the fluid temporary storage unit
through the connection pipe. When a fluid pump device including the
control valve is employed in fuel cell systems, the flow rate of
high-temperature outlet gas supplied to the anode inlet of the fuel
cell may be arbitrarily controlled.
[0065] The fluid is not limited and may be an outlet gas discharged
from the outlet of the anode of a fuel cell. The gas may be in the
temperature range of 100.degree. C. to 1000.degree. C. A fuel
(mainly hydrogen or carbon monoxide) that is not fully utilized in
the fuel cell may remain in the gas discharged from the anode
outlet and the fuel utilization may be increased in a case where
the fuel is recirculated and supplied to the fuel cell again.
Therefore, in a case where the anode outlet gas of the fuel cell is
recirculated into the anode inlet of the fuel cell again through
the fluid temporary storage unit of the disclosure, the overall
efficiency of a fuel cell system may be improved.
[0066] According to an embodiment, the fluid pumping device may
include a plurality of fluid temporary storage units. Here, at
least one of the fluid temporary storage units may be positioned
inside the high-temperature unit, and at least one of the fluid
temporary storage units may be positioned outside the
high-temperature unit (see FIG. 6). Particularly, the connection
tube may connect the pump to the first fluid temporary storage unit
and may be drawn therefrom to be connected to the second fluid
temporary storage unit. The connection tube between the first fluid
temporary storage unit and the second fluid temporary storage unit
may further include a control valve that controls the fluid
pressure supplied from the first fluid temporary storage unit to
the second fluid temporary storage unit. The fluid at room
temperature is pumped to the first fluid temporary storage unit,
and the fluid at high temperature is pumped to the second fluid
temporary storage unit.
[0067] According to an embodiment, the fluid pumping device of the
disclosure transmits the fluid pressure to the first fluid
temporary storage unit, and the transmitted fluid pressure is
transmitted to the second to fourth fluid temporary storage units.
Particularly, the first fluid temporary storage unit may be
positioned outside the high-temperature unit, the connection tube
connects the pump to the first fluid temporary storage unit and is
drawn therefrom to branch off to three connection tubes, and the
three branched connection tubes are respectively connected to the
second to fourth fluid temporary storage units to transmit the
fluid pressures to the second to fourth fluid temporary storage
units. The second to fourth fluid temporary storage units are
respectively positioned in the high-temperature units.
Particularly, a control valve is employed on each of the three
connection tubes, and the amount of the fluid pumped to each of the
fluid temporary storage units may be controlled depending on the
fluid temporary storage units (see FIG. 7).
[0068] Hereinafter, Experimental Example in which a fluid at high
temperature is pumped using the fluid pumping device according to
the disclosure are proposed. This is only an example of the
disclosure, and the range of the disclosure is not limited to the
following Experimental Example.
EXPERIMENTAL EXAMPLE
[0069] An experiment is performed as follows to measure the
performance of the fluid pumping device.
[0070] The diaphragm pump and the fluid temporary storage unit are
positioned separately, and the diaphragm pump and the fluid
temporary storage unit are connected with the flexible tube. In
addition, the check valves are positioned at both inlet and outlet
of the fluid temporary storage unit.
[0071] As the diaphragm pump, a product manufactured by KAMOER
(Model No. KVP8DUDC24) is used. As the diaphragm of the pump,
polyphenylensulfide (PPS) diaphragms are used.
[0072] As the check valve, 1/4-inch check valves manufactured by
Parker are used. A check magnitude is 1/3 psi, and the check valves
are of a plate type and include springs and O-rings therein.
[0073] As the fluid temporary storage unit, a 1/4-inch Tee union
manufactured by Hylok is used. The Tee union is configured to have
an internal volume of 2.5 cm.sup.3 and SUS 316 as it material.
[0074] The material of the flexible tube that connects the
diaphragm pump and the fluid temporary storage unit is Teflon and
has a tube diameter of 1/8 inches and a length of 40 cm.
[0075] The check valve and the fluid temporary storage unit are
connected to the anode outlet of the fuel cell to allow the outlet
gas at the anode to flow into the check valve connected to the
inlet of the fluid temporary storage unit, and the check valve
connected to the outlet of the fluid temporary storage unit
positioned on the opposite side to the check valve is connected to
the anode inlet of the fuel cell. In addition, a heat insulation
material is employed between the diaphragm pump and the fluid
temporary storage unit to spatially separate the pump and the fluid
temporary storage unit from each other. Further, the control valve
is connected to the flexible tube to control the amount of the
fluid pressure generated by the pump when the fluid pressure is
transmitted to the fluid temporary storage unit. In the fluid
pumping device configured as described above, the pump is operated
for 100 hours and the outlet gas at high temperature discharged
from the anode outlet of the fuel cell is re-supplied to the anode
inlet of the fuel cell.
[0076] According to the experiment result, the supply rate of the
high-temperature gas is maintained at a constant level (see FIG.
9). In the Experimental Example, the gas at around 200.degree. C.
is supplied. However, in the cases where the types and materials of
the fluid temporary storage unit and the check valves are changed
to be applicable for high temperature gas, a high-temperature gas
at higher than or equal to 500.degree. C. may yield the same
results. Therefore, it is confirmed that the fuel cell is able to
re-supply the anode outlet gas at high temperature through the
fluid pumping device according to the disclosure without requiring
an additional cooling process and reducing the durability of the
pump.
* * * * *