U.S. patent application number 10/415350 was filed with the patent office on 2004-03-04 for high and low pressure gas selector valve of refrigerator.
Invention is credited to De Waele, Alphons, Koyama, Tomohiro.
Application Number | 20040040315 10/415350 |
Document ID | / |
Family ID | 18945389 |
Filed Date | 2004-03-04 |
United States Patent
Application |
20040040315 |
Kind Code |
A1 |
Koyama, Tomohiro ; et
al. |
March 4, 2004 |
High and low pressure gas selector valve of refrigerator
Abstract
There are provided a housing that has a generally
cylindrical-shaped internal circumferential surface, a housing
passage that includes a high-pressure gas passage and a
low-pressure gas passage which are formed on the housing surface, a
generally cylindrical-shaped rotor that is supported by bearings,
and which rotates with a micro-clearance away from the internal
circumferential surface of the housing without touching the
housing, and a rotor passage that is formed inside the rotor, and
through which gas flows at the time its openings align with the
valve housing passage. Load to the rotating axis of the rotor due
to the pressure of the supplied gas to the valve is cancelled, and
the clearance between the rotor and the housing are maintained at a
proper level, by installing pluralities of high-pressure gas supply
ports and low-pressure gas supply ports of the housing in
symmetrical positions relative to the rotating axis of the
rotor.
Inventors: |
Koyama, Tomohiro;
(Shinagawa-ku, JP) ; De Waele, Alphons; (Bh
Veldhoven, NL) |
Correspondence
Address: |
Arent Fox Kintner
Plotkin & Kahn
Suite 400
1050 Connecticut Avenue NW
Washington
DC
20036-5339
US
|
Family ID: |
18945389 |
Appl. No.: |
10/415350 |
Filed: |
May 5, 2003 |
PCT Filed: |
February 12, 2002 |
PCT NO: |
PCT/JP02/01165 |
Current U.S.
Class: |
62/6 |
Current CPC
Class: |
F25B 2309/1413 20130101;
F25B 2309/14241 20130101; F16K 39/06 20130101; F25B 2309/1418
20130101; F25B 2309/1424 20130101; F16K 11/0856 20130101; F25B
9/145 20130101; F25B 2309/14181 20130101; F25B 41/20 20210101; F25B
2309/006 20130101; F25B 2309/1408 20130101; F16K 11/076
20130101 |
Class at
Publication: |
062/006 |
International
Class: |
F25B 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2001 |
JP |
2001-090627 |
Claims
1. A high-low pressure gas directional control valve of a
refrigerator for changing-over periodically between a high-pressure
gas and a low-pressure gas from a compressor comprising: a housing
having a generally cylindrical-shaped internal circumferential
surface; housing passages including high-pressure gas passages and
low-pressure gas passages formed on a wall surface of said housing;
a generally cylindrical-shaped rotor being supported by bearings,
and rotating with a micro-clearance away from said internal
circumferential surface of said housing without touching said
housing; and a rotor passage formed inside said rotor, having gas
flow through it at the time its openings align with said housing
passage; wherein said high-low pressure gas directional control
valve of a refrigerator is characterized by having a plurality of
high-pressure gas supply ports and a plurality of low-pressure gas
supply ports of said housing installed each in a symmetrical
position regarding a rotating axis of said rotor.
2. The high-low pressure gas directional control valve of a
refrigerator according to claim 1, characterized by having a
low-pressure gas supply port of said housing in a same plane as
said high-pressure gas supply port.
3. The high-low pressure gas directional control valve of a
refrigerator according to claim 1 or claim 2, characterized in that
the high-pressure gas or low-pressure gas flowing into said rotor
passage is made to be supplied to said refrigerator through
passages formed along a central axis of said rotor, and also formed
on an edge face of said housing.
4. The high-low pressure gas directional control valve of a
refrigerator according to claim 3, characterized in that said
passage formed along the central axis of said rotor is made to have
openings on both end faces of said rotor.
5. The high-low pressure gas directional control valve of a
refrigerator according to any one of the claims 1 to 4, at least
one of the housing and the rotor is provided with a slit to adjust
timing.
6. A refrigerator using the high-low pressure gas directional
control valve of a refrigerator according to any one of the claims
1 to 5.
7. A cryogenic device using the refrigerator according to claim 6.
Description
TECHNICAL FIELD
[0001] The present invention relates to a high-low pressure gas
directional control valve of a refrigerator, and particularly
relates to a high-low pressure gas directional control valve of a
refrigerator that can be made longer in life, higher in efficiency,
more compact, and lighter, no wear, no dust formation and which is
suitable for using in pulse tube coolers and Gifford McMahon (GM)
cryocoolers.
BACKGROUND ART
[0002] In pulse tube coolers and GM cryocoolers, a high-low
pressure gas directional control valve 14 is used to change-over
periodically between high-pressure gas and low-pressure gas
generated by a compressor 10, and to send them to a refrigerator
12, as shown in FIG. 1. In the figure, reference numeral 12A
denotes a pulse tube, 12B denotes a heat regenerator tube, 12C
denotes a cooling stage, 16 denotes an orifice, and 18 denotes a
buffer tank.
[0003] As described in Japanese Patent No.2617681 and shown in FIG.
2, for example, a conventional high-low pressure gas directional
control valve is composed of: a valve main body 20 that is
whirl-stopped to a valve housing 26 by a pin 22 whose form is shown
in FIG. 3 and to which spring force is applied toward a valve plate
30 by a coil spring 24; the valve housing 26 for accommodating the
valve main body 20; a valve plate 30 in the form shown in FIG. 4; a
drive motor 32 for rotating the valve plate 30, and a motor casing
34 for accommodating the drive motor 32.
[0004] A space 26b on the left side of aforementioned valve main
body 20 is connected to the high-pressure gas side of the
compressor (not shown) through a high-pressure gas passage 26a of
the valve housing 26. On the other hand, a space 34b on the right
side of the valve plate 30 is connected to the low-pressure gas
side of the compressor through a low-pressure gas passage 34a of
the motor casing 34. Through actions of the pressure difference and
the spring 24, the valve main body 20 is pressed against the valve
plate 30. This seals the gas flowing through a valve main body
high-pressure gas passage 20a, a valve plate high-pressure gas
passage 30a, a valve plate low-pressure gas passage 30b, and a
valve main body refrigerator side gas passage 20b, those of which
are located along the valve main body 20 and the valve plate
30.
[0005] In FIG. 2, reference numeral 36 denotes a bearing that
supports the valve-plate 30 so as that the plate can freely
rotate.
[0006] Either of the aforementioned valve main body 20 or valve
plate 30 (the valve plate 30 in this case) is rotated by the drive
motor 32, and the other (the valve main body 20 in this case) is
whirl-stopped. The gas is changed-over at the timing and opening
following the pattern formed on the contact face as shown in FIG. 5
(high-pressure supplying state) and FIG. 6 (low-pressure recovering
state). As a result, gas flows through passages or space
26a.fwdarw.26b.fwdarw.20a.fwdarw.30a .fwdarw.20b .fwdarw.26c
(high-pressure supplying state), or passages or space
26c.fwdarw.20b.fwdarw.30b.fwdarw.34b.fwdarw.34a (low-pressure
recovering state as shown in FIG. 2) formed in the interior, and
the gas is supplied to or recovered from the refrigerator through
valve housing refrigerator side gas passage 26c.
[0007] However, in this kind of high-low pressure gas directional
control valve, the valve main body 20 is pressed against the valve
plate 30 and is sealed by the sliding surface, hence the valve main
body 20 and the valve plate 30 wear out, and periodic replacement
is required. Moreover, the sliding surface resistance is high,
necessitating use of a large sized high torque motor as the drive
motor 32, which leads to a bigger size of the unit itself.
Furthermore, there have been problems such as the passage formed in
the valve main body 20 and the valve plate 30 becoming
sophisticated in form, which led to increase in pressure loss, and
the decrease in performance of the refrigerator.
[0008] Moreover, in Japanese Patent Laid-Open Publication
No.2001-91078 as shown in FIG. 7, a rotary valve has been proposed,
which consists of a circular horizontally-section rotor 101 that
rotates around the central axis, and a housing 102 that
accommodates this rotor 101 so as to freely rotate. In this rotary
valve, a plurality of ports 105 to 112 are installed on the
external circumferential surface of the aforementioned rotor 101,
and a plurality of ports 117 to 122 corresponding to the
aforementioned ports 105 to 112 are also installed on the internal
circumferential surface of the aforementioned housing 102. This
rotary valve changes-over, by the rotation of the aforementioned
rotor 101, between the state in which the ports in both groups 105
to 108, 117, 118, 120, 122 connect communicatively by matching the
prescribed ports 105 to 108 of the rotor 101 to the corresponding
ports 117, 118, 120, 122 of the aforementioned housing 102, and the
state in which the ports in both groups 105 to 108, 117, 118, 120,
122 do not connect communicatively due to disengagement of the
aforementioned matching. In the figure, reference numeral 103
denotes an axle-bearing, and reference numeral 104 denotes a
motor.
[0009] However, there was a problem that it did not operate so
well, with increasing leaks from the high-pressure side to the
low-pressure side, since all the ports are formed asymmetrical
regarding the central axis of the rotor 101, and the valve is not
balanced when pressurized.
DISCLOSURE OF THE INVENTION
[0010] The present invention was made to solve the aforementioned
conventional problems, and it is an object of this invention to
provide a high-low pressure gas directional control valve that can
be made longer in life, higher in efficiency, more compact,
lighter, no wear, and no dust information.
[0011] The present invention solved the aforementioned problems by
the following means, in the high-low pressure gas directional
control valve of a refrigerator that is used to change-over
periodically between high-pressure gas and low-pressure gas from a
compressor. That is, by providing a housing that has a generally
cylindrical-shaped internal circumferential surface, several
housing passages that include high-pressure gas passages and
low-pressure gas passages formed on a wall surface of the housing,
a generally cylindrical-shaped rotor supported by bearings and
which rotates with a micro-clearance away from the internal
circumferential surface of the aforementioned housing without
touching the housing, and a rotor passage formed inside the rotor,
through which gas flows at the time its openings align with the
aforementioned housing passage, wherein pluralities of
high-pressure gas supply ports and low-pressure gas supply ports of
the aforementioned housing are provided in symmetrical position
regarding the rotating axis of the aforementioned rotor.
[0012] Furthermore, a low-pressure gas supply port of the housing
is provided in a same plane as the high-pressure gas supply port,
so that harmful moment does not affect to a rotor axis due to
pressure of the supplied high-pressure gas and low-pressure
gas.
[0013] Furthermore, the high-pressure gas or low-pressure gas
flowing into the aforementioned rotor passage is made to be
supplied to the refrigerator, through passages formed along a
central axis of the rotor and on an edge face of the housing.
[0014] Furthermore, the aforementioned passage formed along the
central axis of the rotor is made to have openings on both end
faces of the rotor, making the pressure at both ends equal, which
cancels the load along the central axis of the rotor, and maintains
the position of the rotor at a proper position, and which also
reduces the load on the motor.
[0015] Furthermore, at least one of the housing and the rotor may
be provided with a slit to adjust timing.
[0016] The present invention also provides a refrigerator that uses
the aforementioned high-low pressure gas directional control
valve.
[0017] The present invention also provides a cryogenic device that
uses the aforementioned refrigerator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a block diagram showing the overall construction
of an example of a pulse tube cooler, which is a target application
of the present invention.
[0019] FIG. 2 is a longitudinal sectional view showing the overall
construction of an example of conventional high-low pressure gas
directional control valve.
[0020] FIG. 3 is a perspective view showing the form of a valve
main body in the same valve.
[0021] FIG. 4 is a perspective view showing the form of a valve
plate in the same valve.
[0022] FIG. 5 is a front view showing the relative relation of the
valve main body and the valve plate in a high-pressure gas
supplying state, in the same valve.
[0023] FIG. 6 is a front view showing the relative relation of the
valve main body and the valve plate in a low-pressure gas supplying
state, in the same valve.
[0024] FIG. 7 is a longitudinal sectional view showing a
construction of a conventional rotary valve disclosed in Japanese
Patent Laid-Open Publication No.2001-91078.
[0025] FIG. 8 is a longitudinal sectional view showing the overall
construction of an embodiment of a high-low pressure gas
directional control valve according to the present invention.
[0026] FIG. 9 is a cross sectional view showing a high-pressure gas
supplying state in the same embodiment.
[0027] FIG. 10 is a cross sectional view showing a low-pressure gas
supplying state in the same embodiment.
[0028] FIG. 11 is a perspective view showing a valve housing that
is used in the aforementioned embodiment.
[0029] FIG. 12 is a perspective view showing a rotor that is used
in the same embodiment.
[0030] FIG. 13 is a piping diagram showing an example where the
present invention is applied to a four-valve type pulse tube
cooler.
[0031] FIG. 14 is a piping diagram showing an example where the
present invention is applied to an active-buffer type pulse tube
cooler.
BEST MODE FOR CARRYING OUT THE INVENTION
[0032] A detailed description of embodiments of the present
invention will be described in detail hereafter, with references to
the drawings.
[0033] A high-low pressure gas directional control valve of this
embodiment is provided with the following, as shown in FIG. 8
(longitudinal sectional view), FIG. 9 (cross sectional view in a
state of high-pressure gas being supplied to a refrigerator), and
FIG. 10 (cross sectional view in a state of low-pressure gas being
supplied to a refrigerator): a valve housing 42 having a generally
cylindrical-shaped internal circumferential surface, of a form
shown in FIG. 11; a pair of high-pressure gas passages 42a and a
pair of low-pressure gas passages 42b (generically called housing
passages) formed axially symmetrical on the wall surface of the
valve housing 42; a generally cylindrical-shaped rotor 46 as shown
in FIG. 12, which is supported by bearings 44 and 45, and which
rotates with a micro-clearance 43 away from the internal
circumferential surface of the housing 42 without touching the
valve housing 42; a direction control gas passage 46a and a
refrigerator side gas passage 46b (generically called rotor
passages) that are formed inside the rotor 46, and through which
gas flows at the time its openings align with the passages 42a or
42b of the valve housing 42.
[0034] Sealing of the gas is done by the micro-clearance 43 between
the rotor 46 and the housing 42. Consequently, the micro-clearance
43 can be made to be, for example, from 5 to 100 .mu.m. That is, it
is preferable to have a clearance of 5 .mu.m or greater to prevent
contact, and 100 .mu.m or less to prevent unfavorable effects on
the performance of the refrigerator.
[0035] In FIG. 8, reference numeral 50 denotes a drive motor for
rotating the rotor 46 through a coupling 52, and reference numeral
54 denotes a casing of the drive motor 50, and reference numeral
54a denotes a space inside the casing 54.
[0036] In this embodiment, the rotor 46 supported by the two
bearings 44 and 45 rotates without touching the housing 42.
passages are formed in the rotor 46 and housing 42, and gas flows
through the rotor passage at the time each of their openings
aligns. That is, as shown in FIG. 9, high-pressure gas is supplied
to the refrigerator through passages or space
42a.fwdarw.46a.fwdarw.46b.fwdarw.42c, when the high-pressure gas
passages 42a of the valve housing 42 and the direction control
passage 46a of the rotor 46 face to each other. On the other hand,
as shown in FIG. 10, low-pressure gas is recovered from the
refrigerator through passages or space
42c.fwdarw.46b.fwdarw.46a.fwdarw.42b, when the low-pressure gas
passages 42b of the valve housing 42 and the direction control
passage 46a of the rotor 46 face to each other.
[0037] Two channels of high-pressure gas supply ports 42a from the
compressor are installed on symmetrical positions regarding the
rotor 46 axis, and both of them are connected in a vertical
direction regarding the rotor axis. Since there are two channels in
axially symmetrical positions, vertical load on the rotating axis
of the rotor 46 due to the pressure of the supplied high-pressure
gas is cancelled, and the clearance 43 between the rotor 46 and the
housing 42 is maintained at a proper level, preventing unbalanced
clearance and partial wear of the rotor, and reducing the load on
the motor 50.
[0038] Low-pressure gas supply ports 42b from the compressor are of
the same construction as the high-pressure gas side, and form
passages at the same plane but with 90 degrees angle relative to
high-pressure gas passages 42a.
[0039] A space 54a inside the casing, where the drive motor 50 is
installed, is connected communicatively to the space 42c that is
used for supplying to the refrigerator, through the rotor passage
46b. This cancels the axial load on the rotor 46 by maintaining the
same pressure all the time, and keeps the rotor 46 at a proper
position, preventing unbalanced clearance and partial wear of the
rotor, and also reducing the load on the motor 50.
[0040] In this kind of structure, sealing is done by the rotor 46
and the housing 42 in a non-contact state, hence there are no
sliding surfaces, and regular replacement of parts are not
required. It should be noted that, there are some leaks because it
is a non-contact sealing, but this problem is small compared to the
flow rate supplied to the refrigerator.
[0041] Furthermore, by balancing the pressure, the load on the
drive motor 50 is decreased by making the rotating resistance of
the rotor 46 as small as possible. Hence smaller motors can be
adopted, enabling smaller and lighter units, and enabling lower
power consumption.
[0042] Furthermore, by balancing the pressure, the micro-clearance
43 for sealing can be secured with stability. Furthermore, a high
efficiency operation with little pressure loss is possible, since
the passage shape is simple.
[0043] In this embodiment, slits 42s and 46s are provided to both
the housing 42 and the rotor 46. So, change-over timing of the
valve can be changed easily. However, one of the slits 42s and 46s
or both may be omitted.
[0044] The loss due to leak from the micro-clearance 43 for sealing
of the high-low pressure gas directional control valve in the
following conditions was approximately 40W, which was 0.5% of
compressor input, and was within the range of being negligible.
Here, the outer diameter of the valve rotor 46 was 20 mm, the
overall length of the valve rotor was 24 mm, the inner diameter of
the gas passages 42a to 42c, 46a, and 46b each were 3 mm, and the
micro-clearance 43 for sealing was 15 .mu.m. A geared compact DC
motor, with a variable selectable frequency of 1 to 10 Hz by the
change of the drive voltage, was used for the drive motor 50, using
drive voltage 1-24V and DC drive current 5 mA (at DC 3V drive). And
bearings 44, 45 with general-use specifications were used.
[0045] The valve unit according to the present invention can also
be applied to a phase control mechanism for a pulse tube cooler,
aside from various pulse tubes.
[0046] In case of a four-valve type pulse tube cooler, as shown in
FIG. 13, a phase control at a high temperature end of the pulse
tube 12A is achieved by means of two switching valves 61 and 62
instead of a buffer. One end of each of the two valves 61 and 62 is
connected to the high temperature end of the pulse tube 12A via a
common orifice 16. The other ends thereof are connected to the
high-pressure gas supply line and the low-pressure gas supply line
of the compressor 10, respectively. The two valves are controlled
so as to periodically open and close according to a predetermined
timing chart to provide an optimal phase between the pressure
variation and the gas displacement inside the pulse tube, thereby
obtaining a desired refrigerating performance.
[0047] This phase control valve is operated in the same manner as
that of the high-low pressure switching valve unit 14 arranged
between the regenerator 12B and the compressor 10. Thus, the valve
unit according to the present invention can be applied to the
four-valve type phase control valve.
[0048] In case of an active-buffer type pulse tube cooler, as shown
in FIG. 14, the phase control at the high temperature end of the
pulse tube 12A is not achieved by the combination of one buffer and
an orifice, but by the combination of two or more buffers 18 and 19
and the same number of switching valves 61 and 62. These buffers 18
and 19 are kept in a medium pressure state which is a state between
the high pressure and low pressure states of the compressor.
However, the respective pressures in the buffers are different from
each other. The buffers are connected to the high temperature end
of the pulse tube via the respective switching valves. The
respective switching valves are controlled so as to periodically
open and close, according to a predetermined timing chart to
provide an optimal phase between the pressure variation and the gas
displacement inside the pulse tube, thereby obtaining a desired
refrigerating performance.
[0049] This phase control valve is operated in the same manner as
that of the high-low pressure switching valve unit 14 arranged
between the regenerator 12B and the compressor 10. Thus, the valve
unit according to the present invention can be applied to the
active-buffer type phase control valve.
[0050] Further, since there is no wear, it can also be applied to a
low temperature application.
[0051] Industrial Applicability
[0052] The present invention can be used in a high-low pressure gas
directional control valve of a refrigerator for extremely low
temperature, such as GM cryocoolers and pulse tube coolers etc.
[0053] According to the present invention, it is possible to
maintain the clearance between the rotor and the housing at a
proper level, and also to reduce the load on the motor, by having a
balanced axial and vertical load on the rotating axis of the rotor.
Therefore, it is possible to make the high-low pressure gas
directional control valve longer in life, higher in efficiency,
more compact, lighter, no wear and no dust formation enabling a
long term, stable operation, and a drive motor that is more compact
and lower in power consumption.
* * * * *