U.S. patent application number 10/315221 was filed with the patent office on 2004-01-15 for valve assembly and airconditioning system including same.
Invention is credited to Benatav, Dror.
Application Number | 20040007008 10/315221 |
Document ID | / |
Family ID | 27271837 |
Filed Date | 2004-01-15 |
United States Patent
Application |
20040007008 |
Kind Code |
A1 |
Benatav, Dror |
January 15, 2004 |
Valve assembly and airconditioning system including same
Abstract
A valve assembly for controlling the flow of a fluid between a
plurality of ports including at least one high pressure port and
one low pressure port, includes: a base mounting the plurality of
ports; and a valve member rotatable to a selected operational
position with respect to the base. The control face of the valve
member is formed with a low pressure cavity in the central region,
and with an annular high pressure cavity in the outer region
completely circumscribing the low pressure cavity. Such an
arrangement produces a balanced valve construction which permits
the valve member to be selectively rotated to the selected
operational position, or to any intermediate position, while
substantially isolating the high pressure from the low pressure in
all its positions. This permits the valve assembly to be used not
only as conventional change-over valve in an air conditioning
system to select either a heating mode or cooling mode of
operation, but also as a control valve to perform one or more
additional control functions, e.g. for temperature or output
control purposes, in any operational positions of the valve
member.
Inventors: |
Benatav, Dror; (Tel Aviv,
IL) |
Correspondence
Address: |
EITAN, PEARL, LATZER & COHEN ZEDEK LLP
10 ROCKEFELLER PLAZA, SUITE 1001
NEW YORK
NY
10020
US
|
Family ID: |
27271837 |
Appl. No.: |
10/315221 |
Filed: |
December 10, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10315221 |
Dec 10, 2002 |
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09489806 |
Jan 24, 2000 |
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6491063 |
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09489806 |
Jan 24, 2000 |
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09096563 |
Jun 12, 1998 |
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6076365 |
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Current U.S.
Class: |
62/324.6 ;
137/119.02; 137/625.43; 62/324.1 |
Current CPC
Class: |
Y10T 137/86839 20150401;
Y10T 137/2678 20150401; F25B 41/26 20210101 |
Class at
Publication: |
62/324.6 ;
62/324.1; 137/119.02; 137/625.43 |
International
Class: |
G05D 011/00; F25B
013/00; E03B 001/00; E03C 001/00; F17D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 1998 |
IL |
123184 |
Sep 17, 1997 |
IL |
121794 |
Claims
1. A valve assembly for controlling the flow of a fluid between a
plurality of ports including at least one high pressure port and
one low pressure port, comprising: a base mounting said plurality
of ports; and a valve member rotatable to a plurality of
operational positions with respect to said base, said valve member
having a control face facing said base to control the flow of fluid
between said ports according to the position of the valve member
with respect to said base, and an opposite face facing away from
said base; said control face of the valve member being formed with
a low pressure cavity in the central region thereof, and with an
annular high pressure cavity in the outer region thereof completely
circumscribing said low pressure cavity.
2. The valve assembly according to claim 1, further comprising: a
slow-acting vent for applying high pressure from said high pressure
cavity to said opposite face of the valve member, when the valve
member is in an operational position, to firmly press the valve
member into sealing contact with the base, and thereby to isolate
the high pressure cavity from the low pressure cavity; a pilot
valve which is normally closed but selectively openable to release
the high pressure applied to said opposite face of the valve
member, and thereby to enable the valve member to be moved to
another operational position; and a passageway from said annular
high pressure section of the valve member to said opposite face of
the valve member to maintain said control face of the valve member
sufficiently close to said base to substantially isolate the high
pressure cavity from the low pressure cavity also when said pilot
valve is open and said valve member is moved to another operational
position.
3. The valve assembly according to claim 2, wherein said pilot
valve, when opened, connects the high pressure at said opposite
face of the valve member to said low pressure cavity to release the
high pressure applied to said opposite face of the valve
member.
4. The valve assembly according to claim 2, further comprising: a
rotary motor drive including an electrical motor, and a control
circuit therefor for selectively moving the valve member from one
operational position to another operational position in order to
change-over the connections between said high pressure and low
pressure ports, or to an intermediate position between said two
operational positions in order to control the fluid flow with
respect to said ports without making a change-over of the
connections between said high pressure and low pressure ports.
5. The valve assembly according to claim 4, wherein said control
circuit controls said rotary motor drive to selectively move said
valve member to any one of a plurality of intermediate
positions.
6. The valve assembly according to claim 4, wherein said control
face of the valve member is constructed such that moving the valve
member to said intermediate position controls fluid leakage from
said high pressure cavity to said low pressure cavity.
7. The valve assembly according to claim 4, wherein said control
face of the valve member is constructed such that moving the valve
member to said intermediate position controls the effective
cross-sectional area of said low pressure port exposed to said
low-pressure cavity of the valve member.
8. The valve assembly according to claim 4, wherein said rotary
motor drive also controls said pilot valve to selectively open or
close it at any one of said operational or intermediate
positions.
9. The valve assembly according to claim 8, wherein said rotary
motor drive drives said valve member via a coupling disk which is
directly coupled to the rotary motor drive and is coupled to the
valve member via a lost-motion coupling such that the coupling disk
may be rotated a small amount to open or close the pilot valve
without rotating the valve member.
10. The valve assembly according to claim 9, wherein said coupling
disk includes a spring-biased pin receivable within a recess in the
valve member to releasably retain the coupling disk in a normal
position closing said pilot valve, but rotatable by said rotary
motor drive with respect to said valve member to open or close said
pilot valve in any position of the valve member.
11. The valve assembly according to claim 9, wherein said coupling
disk includes a pair of diametrically opposed spring-biased pins
receivable within diametrically-opposed recesses in the valve
member to retain the coupling disk in said normal position with
respect to said pilot valve.
12. The valve assembly according to claim 9, wherein said
lost-motion coupling between said coupling disk and said valve
member comprises a projection carried by said coupling disk movable
within a slot in said valve member.
13. The valve assembly according to claim 1, wherein said control
face of the valve member is formed with a rib formation including
inner and outer concentric, closed-loop ribs defining said low
pressure cavity within the inner closed-loop rib, and said high
pressure cavity between the two closed-loop ribs.
14. The valve assembly according to claim 13, wherein said
closed-loop ribs are shaped such that, at least at one intermediate
position of the valve member between its two operational positions,
said ribs partially shunt fluid from said high pressure cavity to
said low pressure cavity.
15. The valve assembly according to claim 13, wherein said
closed-loop ribs are shaped such that, at least at one intermediate
position of the valve member between its two operational positions,
said ribs reduce the effective cross-sectional area of the low
pressure port exposed to said low pressure cavity.
16. The valve assembly according to claim 13, further comprising:
at least one shunting port, and a shunting line from said shunting
port for partially shunting fluid away from one of said cavities;
said closed-loop ribs being shaped such that, at one intermediate
position of the valve member, said ribs partially shunt fluid away
from said one cavity.
17. The valve assembly according to claim 16, wherein there are a
shunting port and a shunting line for each of said cavities, said
closed loop ribs being shaped such that at each of two different
intermediate positions of the valve member, said ribs partially
shunt fluid away from one of said cavities via one of said shunting
lines.
18. The valve assembly according to claim 1, further comprising: a
rotary motor drive, and a coupling disk for driving said valve
member; said base and valve member being enclosed in a
hermetically-sealed housing; said rotary motor drive being located
externally of said housing and coupled to said valve member by
permanent magnets carried on a driving disk located externally of
said housing and coupled to the rotary motor drive, and on a driven
disk located within said housing and coupled to the valve
member.
19. The valve assembly according to claim 1, wherein said plurality
of ports include a third port and a fourth port located on opposite
sides of said high pressure port such that: in a first operational
position of the valve member, said third port is connected to said
low pressure port and said fourth port is connected to said high
pressure port; and in a second operational position of the valve
member, said third port is connected to said high pressure port,
and said fourth port is connected to said low pressure port.
20. The valve assembly according to claim 19, in combination with:
a compressor having a high pressure side connected to said high
pressure port, and a low pressure side connected to said low
pressure port; a first heat exchanger connected to said third port;
and a second heat exchanger connected to said fourth port; such
that in one operational position of the valve member, the valve
member connects said first heat exchanger to said low pressure
port, and said second heat exchanger to said high pressure port;
and in an second operational position of the valve member, the
valve member connects said first heat exchanger to said high
pressure port and said second heat exchanger to said low pressure
port.
21. An air-conditioning system for air-conditioning an enclosed
space by compressing and expanding a fluid, comprising: an inside
heat exchanger to be located within the enclosed space; an outside
heat exchanger to be located outside the enclosed space; a
compressor having a low pressure side and a high pressure side; and
a change-over valve including: a base having a low pressure port
connected to said low pressure side of the compressor, and a high
pressure port connected to the high pressure side of the
compressor; a valve member rotatable with respect to said base; a
rotary motor drive for driving said valve member; and a controller
for controlling said rotary motor drive to selectively drive said
valve member; (a) to a first operational position connecting said
low pressure port to said inside heat exchanger and said high
pressure port to said outside heat exchanger to define a low
pressure section including said inside heat exchanger for using the
fluid to cool said enclosed space; and (b) to a second operational
position connecting said high pressure port to said inside heat
exchanger, and said low pressure port to said outside heat
exchanger to define a high pressure section including said inside
heat exchanger for using the fluid to heat said enclosed space;
said controller controlling said rotary motor drive for selectively
driving the valve member to at least one further position, in
addition to said first and second operational positions; said valve
member being constructed to maintain said high pressure section
substantially isolated from said low pressure section and to
perform at least one additional control function, when the valve
member is driven to the further position.
22. The air-conditioning system according to claim 21, wherein said
at least one additional function is to shunt a part of the fluid
from said high pressure port to said low pressure port to thereby
control temperature within the air-conditioning system without
interrupting the operation of the compressor.
23. The air-conditioning system according to claim 21, wherein said
at least one additional function is to restrict the effective
cross-sectional area of said low pressure port with respect to the
heat-exchanger connected thereto, to thereby control the output of
the air-conditioning system without interrupting the operation of
the compressor.
24. The air-conditioning system according to claim 21, wherein said
base includes a shunting port connected to a shunting line; and
wherein said at least one additional function is to shunt a part of
the fluid via said shunting line from a high pressure location to a
low pressure location in the air-conditioning system, to thereby
control temperature within the air-conditioning system without
interrupting the operation of the compressor.
25. The air-conditioning system according to claim 24, wherein said
base includes two shunting lines connected to two shunting ports,
and said valve member selectively connects one shunting line to
said inside heat exchanger, and the other shunting line to said
outside heat exchanger, according to the further position to which
the valve member is driven by the controller.
26. The air-conditioning system according to claim 21, wherein said
change-over valve further includes a pilot valve between said high
pressure and low pressure ports; and said controller selectively
opens and closes said pilot valve at any position of said valve
member to control leakage from the high pressure port to said low
pressure port for controlling temperature.
27. The air-conditioning system according to claim 21, wherein said
valve member includes a control face facing said base to control
the flow of fluid between said ports according to the position of
the valve member with respect to the base, and an opposite face
facing away from said base; said control face of the valve member
being formed with a low pressure cavity in the central region
thereof, and with an annular high pressure cavity in the outer
region thereof completely circumscribing said low pressure
cavity.
28. The air-conditioning system according to claim 27, further
comprising: a slow-acting vent for applying high pressure from said
high pressure cavity to said opposite face of the valve member,
when the valve member is in an operational position, to firmly
press the valve member into sealing contact with the base, and
thereby to isolate the high pressure cavity from the low pressure
cavity; a pilot valve which is normally closed but selectively
openable to release the high pressure applied to said opposite face
of the valve member, and thereby to enable the valve member to be
moved to another operational position; and a passageway from said
annular high pressure section of the valve member to said opposite
face of the valve member to maintain said control face of the valve
member sufficiently close to said base to substantially isolate the
high pressure cavity from the low pressure cavity also when said
pilot valve is open and said valve member is moved to another
operational position or to a said further position intermediate
said first and second operational positions.
29. The air-conditioning system according to claim 27, wherein said
control face of the valve member is formed with a rib formation
including inner and outer concentric closed-loop ribs defining said
low pressure cavity within the inner closed-loop rib, and said high
pressure cavity between the two closed-loop ribs.
30. The air-conditioning system according to claim 29, wherein said
closed loop ribs are shaped such that, at least at one intermediate
position of the valve member between said first and second
operational positions, said ribs partially shunt fluid from said
high pressure cavity to said low pressure cavity.
31. The air-conditioning system according to claim 29, wherein said
closed-loop ribs are shaped such that, at least at one intermediate
position of the valve member between said first and second
operational positions, said ribs reduce the effective
cross-sectional area of the low pressure port exposed to said low
pressure cavity.
32. The air-conditioning system according to claim 29, further
comprising: at least one shunting port, and a shunting line from
said shunting port for partially shunting fluid away from one of
said cavities; said closed-loop ribs being shaped such that, at one
intermediate position of the valve member between said first and
second operational positions, said ribs partially shunt fluid away
from said one cavity.
33. The air-conditioning system according to claim 32, wherein
there are a shunting port and a shunting line for each of said
cavities, said closed loop ribs being shaped such that at each of
two different intermediate positions of the valve member between
said first and second operational positions, said ribs partially
shunt fluid away from one of said cavities via one of said shunting
lines.
34. The air-conditioning system according to claim 21, wherein said
controller includes a temperature sensor for sensing the
temperature at a predetermined location within the air-conditioning
system and for controlling said rotary motor drive in response to
the sensed temperature.
35. An air-conditioning system for air-conditioning an enclosed
space by compressing and expanding a fluid, comprising: an inside
heat exchanger to be located within the enclosed space; an outside
heat exchanger to be located outside the enclosed space; a
compressor having a low pressure side and a high pressure side; and
a change-over valve including: a base having a low pressure port
connected to said low pressure side of the compressor, a high
pressure port connected to the high pressure side of the
compressor, and at least one shunting port connected to a shunting
line; a valve member rotatable with respect to said base; a rotary
motor drive for driving said valve member; and a controller for
controlling said rotary motor drive to selectively drive said valve
member; (a) to a first position connecting said low pressure ports
to said inside heat exchanger, and said high pressure port to said
outside heat exchanger, to define a low pressure section including
said inside heat exchanger for using the fluid to cool said
enclosed space; (b) to a second position connecting said high
pressure port to said inside heat exchanger and said low pressure
port to said outside heat exchanger, to define a high pressure
section including said inside heat exchanger for using the fluids
to heat said enclosed space; and (c) at least one further position
connecting said shunting port to shunt a part of the fluid via said
shunting line from a high pressure location to a low pressure
location in the air-conditioning system to control temperature
within the air-conditioning system without interrupting the
operation of the compressor.
36. The air-conditioning system according to claim 35, wherein said
change-over valve further includes a pilot valve between said high
pressure and low pressure ports; and said controller selectively
opens and closes said pilot valve at any position of said valve
member to control leakage from the high pressure port to said low
pressure port.
37. The air-conditioning system according to claim 35, wherein said
valve member includes a control face facing said base to control
the flow of fluid between said ports according to the position of
the valve member with respect to the base, and an opposite face
facing away from said base; said control face of the valve member
being formed with a low pressure cavity in the central region
thereof, and with an annular high pressure cavity in the outer
region thereof completely circumscribing said low pressure
cavity.
38. The air-conditioning system according to claim 37, further
comprising: a slow-acting vent for applying high pressure from said
high pressure cavity to said opposite face of the valve member,
when the valve member is in an operational position, to firmly
press the valve member into sealing contact with the base, and
thereby to isolate the high pressure cavity from the low pressure
cavity; a pilot valve which is normally closed but selectively
openable to release the high pressure applied to said opposite face
of the valve member, and thereby to enable the valve member to be
moved to another operational position; and a passageway from said
annular high pressure section of the valve member to said opposite
face of the valve member to maintain said control face of the valve
member sufficiently close to said base to substantially isolate the
high pressure cavity from the low pressure cavity also when said
pilot valve is open and said valve member is moved to another
operational position or to said further position.
39. The air-conditioning system according to claim 37, wherein said
control face of the valve member is formed with a rib formation
including inner and outer concentric closed-loop ribs defining said
low pressure cavity within the inner closed-loop rib, and said high
pressure cavity between the two closed-loop ribs.
40. The air-conditioning system according to claim 39, wherein said
closed-loop ribs are shaped such that, at least at one further
position of the valve member intermediate its two operational
positions, said ribs partially shunt fluid from said high pressure
cavity to said low pressure cavity.
41. The air-conditioning system according to claim 39, wherein said
closed-loop ribs are shaped such that, at least at one further
position of the valve member intermediate its two operational
positions, said ribs reduce the effective cross-sectional area of
the low pressure port exposed to said low pressure cavity.
42. An air-conditioning system for air-conditioning an enclosed
space by compressing and expanding a fluid, comprising: an inside
heat exchanger to be located within the enclosed space; an outside
heat exchanger to be located outside the enclosed space; a
compressor having a low pressure side and a high pressure side; and
a change-over valve including: a base having a low pressure port
connected to said low pressure side of the compressor, and a high
pressure port connected to the high pressure side of the
compressor; a valve member rotatable with respect to said base; a
pilot valve connecting the high pressure port to the low pressure
port of the change-over valve; a rotary motor drive for driving
said valve member; and a controller for controlling said rotary
motor drive to selectively drive said valve member; said controller
also controlling said pilot valve to selectively open or close it
in any position of the valve member to produce a controlled leakage
from said high pressure side to said low pressure side of the
compressor.
43. The air-conditioning system according to claim 42, wherein said
rotary motor drive drives said valve member via a coupling disk
which is directly coupled to the rotary motor drive and is coupled
to the valve member via a lost-motion coupling such that the
coupling disk may be rotated a small amount to open or close the
pilot valve without rotating the valve member.
44. The air-conditioning system according to claim 43, wherein said
coupling disk includes a spring-biased pin receivable within a
recess in the valve member to releasably retain the coupling disk
in a normal position closing said pilot valve, but rotatable by
said rotary motor drive with respect to said valve member to open
or close said pilot valve in any position of the valve member.
45. The air-conditioning system according to claim 43, wherein said
coupling disk includes a pair of diametrically opposed
spring-biased pins receivable within diametrically-opposed recesses
in the valve member to retain the coupling disk in a normal
position with respect to said pilot valve.
46. The air-conditioning system according to claim 43, wherein said
lost-motion coupling between said coupling disk and said valve
member comprises a projection carried by said coupling disk movable
within a slot in said valve member.
47. A method of air conditioning an enclosed space, comprising:
providing an air conditioning system according to claim 21; and
selectively actuating said valve assembly; (a) to said first
operational position to effect a cooling mode of operation; (b) to
said second operational position to effect a heating mode of
operation; or (c) to said at least one further position, to produce
a control of the air-conditioning system in the respective mode of
operation without interrupting the operation of the
air-conditioning system.
48. The method according to claim 47, wherein said valve assembly
is actuated to said further position to produce a controlled
leakage between said high pressure port to said low pressure port
to prevent frosting without interrupting the operation of the
air-conditioning system.
49. The method according to claim 48, wherein the ambient
temperature is sensed by a temperature sensor, and the output of
said temperature sensor is used to automatically control the valve
assembly to prevent frosting by actuating the valve from one
operational position to said further position.
50. The method according to claim 47, wherein said valve assembly
is actuated to said further position to produce a controlled
reduction in the cross-sectional area of said low pressure port in
the base to reduce the output of the air-conditioning system
without interrupting its operation.
51. The method according to claim 47, wherein said change-over
valve includes a pilot valve, and said controller selectively opens
or closes said pilot valve at any one of said operational or
further positions to produce a controlled leakage from the high
pressure side to the low pressure side of the compressor for
temperature control purposes.
52. The method according to claim 47, wherein said base includes a
shunting port connected to a shunting line, and said rotary motor
drive is controlled to selectively connect said shunting line to
shunt a part of the fluid via said shunting port from a high
pressure location to a low pressure location in the
air-conditioning system to control temperature within the
air-conditioning system without interrupting the operation of the
compressor.
53. The valve assembly according to claim 19, further comprising: a
first shunting port and a first shunting line from said first
shunting port and second shunting port and a second shunting line
from said second shunting port for at least partially shunting
fluid away from one of said cavities via one of said shunting
lines.
54. The valve assembly according to claim 53, wherein said pilot
valve is an expansion valve which when opened, connects the high
pressure at said opposite face of the valve member to said low
pressure cavity to release the high pressure applied to said
opposite face of the valve member.
55. The valve assembly according to claim 54, in combination with:
a compressor having a high pressure side connected to said high
pressure port, and a low pressure side connected to said low
pressure port; a first heat exchanger connected to said third port;
and a second heat exchanger connected to said fourth port; wherein
said valve member connects said first heat exchanger to said low
pressure port, and said second heat exchanger to said high pressure
port; and such that, in one operational position of the valve
member, the direction of flow is from said first heat exchanger to
said second heat exchanger and in a second operational position of
the valve member, the direction of flow is from said second heat
exchanger to said first heat exchanger.
56. The air-conditioning system according to claim 29, further
comprising: a first shunting port and a first shunting line from
said first shunting port and second shunting port and a second
shunting line from said second shunting port for at least partially
shunting fluid away from one of said cavities via one of said
shunting lines.
57. The air-conditioning system according to claim 56, wherein said
pilot valve is an expansion valve which when opened, connects the
high pressure at said opposite face of the valve member to said low
pressure cavity to release the high pressure applied to said
opposite face of the valve member.
58. The air-conditioning system according to claim 42, further
comprising: a first shunting port and a first shunting line from
said first shunting port, and second shunting port and a second
shunting line from said second shunting port for at least partially
shunting fluid away from one of said cavities via one of said
shunting lines.
59. The method according to claim 47, wherein said change-over
valve includes an expansion valve, and said controller selectively
opens or closes said expansion valve at any one of said operational
or further positions to direct the flow of gasses from said first
heat exchanger to said second heat exchanger or vice versa.
60. The method according to claim 47, wherein said base includes a
first shunting port and a first shunting line from said first
shunting port, and second shunting port and a second shunting line
from said second shunting port for at least partially shunting
fluid away from one of said cavities via one of said shunting
lines.
61. The method according to claim 47, wherein said first
operational position includes the step of actuating said valve
assembly thereby to divert gasses from said first shunting port via
said first shunting line, and said second operational position
includes the step of actuating said valve assembly thereby to
divert gasses from said second shunting port via said second
shunting line.
Description
CROSS REFERENCE TO OTHER APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 09/489,806 filed on Jan. 24, 2000, which is a
continuation in part of U.S. application Ser. No. 09/096,563 filed
on Jun. 12, 1998 now U.S. Pat. No. 6,076,365.
FIELD OF THE INVENTION
[0002] The present invention relates to valve assemblies for
controlling the flow of a fluid between a plurality of ports. The
invention is particularly useful as a four-way change-over valve
assembly in an air conditioning system, and method, for selectively
operating the system according to a cooling mode or a heating mode,
and is therefor described below particularly with respect to that
application, but it will be appreciated that the invention and
features thereof could also advantageously be used in many other
applications.
BACKGROUND OF THE INVENTION
[0003] Four-way change-over valves presently used in air
conditioning systems have to accommodate very large pressure
differentials, in the order of 30 atmospheres or more. Such high
pressure differentials make it difficult to assure that the valve
will not leak in its high pressure section, while at the same time
to permit change-over from one operating condition to another by
the use of a relatively small amount of force. Van Allen U.S. Pat.
No. 2,855,000 addresses this problem in a simple manually-operated
change-over valve providing only a simple change-over operation.
Other four-way change-over valves hereto developed have been of a
relatively complicated and expensive construction, as shown for
example in U.S. Pat. Nos. 5,462,085 and 5,507,315.
[0004] Existing air-conditioning systems are also subject to a
number of other problems. One problem is frosting or icing, which
can occur when the system is operated in the heating mode (during
the winter) or in the cooling mode (during the summer). Should
frosting occur in the heating mode, the usual remedy is to
change-over to the cooling mode in order to heat the outside coil,
and also to shut-off the fan. As a result, considerable energy is
lost, and the heating time and the heating capacity are reduced.
Should frosting occur in the cooling mode, the usual remedy is to
shut-off the compressor and/or to stop or change the speed of the
fan, which thereby also involves a loss of energy, time, and
cooling capacity. Moreover, interrupting the operation of the
compressor is unhealthy to the compressor and requires waiting
several minutes before its operation can be resumed. Further, to
prevent frosting in the cooling mode, the system is generally
designed to operate the evaporator at a temperature significantly
above freezing, e.g. about 7.degree. C., to accommodate changes in
the outside temperature; this also reduces the efficiency and
cooling capacity of the system as compared, for example, when
operating at a temperature closer to 0.degree. C.
[0005] Another problem involved in present air-conditioning systems
is in reducing the cooling or heating capacity of the system, e.g.
when the volume of the enclosed space to be cooled or heated is
significantly reduced as by shutting off rooms, etc. The present
air-conditioning systems are generally merely turned-off in order
to reduce the cooling or heating capacity. However, this manner of
reducing the capacity also reduces the overall efficiency of the
system and wastes energy. Moreover, frequent interruption of the
system tends to reduce the useful life of the compressor and the
fan.
OBJECTS AND SUMMARY OF THE INVENTION
[0006] An object of the present invention is to provide an improved
valve assembly which can accommodate large pressure differentials
without leakage, which can be actuated from one operating condition
to another by the use of a relatively small amount of force, and
which can provide other controls, particularly with respect to
temperature and/or output. Another object of the present invention
is to an air conditioning method and system including a valve
assembly which may be used not only as a normal change-over valve
for changing-over the operation of the system from cooling to
heating and vice versa, but which also may be used as a control
valve for performing many control functions within each operational
mode, including preventing frosting, defrosting, reducing system
capacity when required, etc., in a more efficient manner than in
the present air-conditioning systems.
[0007] According to one aspect of the present invention, there is
provided a valve assembly for controlling the flow of a fluid
between a plurality of ports including at least one high pressure
port and one low pressure port, comprising: a base mounting the
plurality of ports; and a valve member rotatable to a plurality of
operational positions with respect to the base. The valve member
has a control face facing the base to control the flow of fluid
between the ports according to the position of the valve member
with respect to the base, and an opposite face facing away from the
base. The control face of the valve member is formed with a low
pressure cavity in the central region thereof, and with an annular
high pressure cavity in the outer region thereof completely
circumscribing the low pressure cavity.
[0008] According to further features in the described preferred
embodiments, the valve assembly further comprises a slow-acting
vent for applying high pressure from the high pressure cavity to
the opposite face of the valve member, when the valve member is in
an operational position, to firmly press the valve member into
sealing contact with the base, and thereby to isolate the high
pressure cavity from the low pressure cavity; a pilot valve which
is normally closed but selectively openable to release the high
pressure applied to the opposite face of the valve member, and
thereby to enable the valve member to be moved to another
operational position; and a passageway from the annular high
pressure section of the valve member to the opposite face of the
valve member to maintain the control face of the valve member
sufficiently close to the base to substantially isolate the high
pressure cavity from the low pressure cavity also when the pilot
valve is open and is moved to another operational position. The
latter isolation is not complete because of a thin air cushion
produced by the high pressure cavity between the base and valve
member completely around the valve member, but is sufficient to
permit the valve also to be used as a control valve to perform a
number of control functions, particularly for temperature control
and/or output control purposes.
[0009] As will be described below, a valve assembly constructed in
accordance with the foregoing features provides a high degree of
protection against leakage from its high pressure section when the
valve assembly is in an operating condition, permits the valve to
be changed-over to another operating condition by the application
of a relatively small amount of force, and further permits the
valve, to be used to perform a number of important control
functions when in either operating position. The valve assembly can
therefore be constructed in a simple, inexpensive and compact form,
as compared to previous constructions, and is particularly useful
in air-conditioning systems to be operated according to a cooling
mode in the summer and a heating mode in the winter.
[0010] According to another aspect of the present invention,
therefore, there is provided an air-conditioning system for
air-conditioning an enclosed space by compressing and expanding a
fluid, comprising: an inside heat exchanger to be located within
the enclosed space; an outside heat exchanger to be located outside
the enclosed space; a compressor having a low pressure side and a
high pressure side; and a changeover valve. The change-over valve
includes: a base having a low pressure port connected to the low
pressure side of the compressor, and a high pressure port connected
to the high pressure side of the compressor; a valve member
rotatable with respect to the base; a rotary motor drive for
driving the valve member; and a controller for controlling the
rotary motor drive to selectively drive the valve member; (a) to a
first position connecting the low pressure port to the inside heat
exchanger and the high pressure port to the outside heat exchanger
to define a low pressure section including the inside heat
exchanger for using the fluid to cool the enclosed space; (b) to a
second position connecting the high pressure port to the inside
heat exchanger, and the low pressure port to the outside heat
exchanger, to the outside heat exchanger, to the define a high
pressure section including the inside heat exchanger for using the
fluid to heat the enclosed space. The controller also controls the
rotary motor drive for selectively driving the valve member to at
least one further position, in addition to and preferably between
the first and second positions. The valve member is constructed to
maintain the high pressure section substantially isolated from the
low pressure section, and to perform at least one additional
control function, when the valve is driven to the further
position.
[0011] One described additional function is to shunt a part of the
fluid from the high pressure port to the low pressure port to
thereby control temperature within the system without interrupting
the compressor. Another described additional function is to
restrict the effective cross-sectional area of the low pressure
port with respect to the heat-exchanger connected to it, to thereby
control the output of the system without interrupting the operation
of the compressor. A further control function is to selectively
open and close the pilot valve, not only for making a change-over
operation, but also for controlling leakage from the high pressure
port to the low pressure port for temperature control purpose in
any position of the valve.
[0012] Such an air-conditioning system can therefore be operated to
perform many diverse control functions, including preventing
frosting or overheating, reducing system capacity, etc., in a
continuous, periodic, when-required manner. This permits the
air-conditioning to be designed for maximum efficiency and to be
continuously controlled according to changing conditions.
[0013] According to a still further aspect of the present
invention, there is provided a method of air-conditioning an
enclosed space providing the advantages described above.
[0014] Further features and advantages of the invention will be
apparent from the description below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention is herein described, by way of example only,
with reference to the accompanying drawings, wherein:
[0016] FIG. 1 is an exploded 3-dimensional view illustrating a
preferred form of valve assembly constructed in accordance with the
present invention;
[0017] FIG. 2 is an exploded 3-dimensional view illustrating only
the base-mounted ports and the opposite side of the valve member
from that shown in FIG. 1;
[0018] FIG. 3 is a sectional view of the valve assembly of FIG. 1
in assembled condition;
[0019] FIG. 4a and 4b illustrate, along section lines IV-IV, FIG.
3, two positions of the coupling disk with respect to the valve
member in FIG. 1;
[0020] FIGS. 5a and 5b illustrate, along section lines V-V, FIG. 3,
the two normal operational positions of the valve member in the
valve assembly of FIG. 1;
[0021] FIGS. 6a and 6b illustrate an air conditioning system
including the valve assembly of FIG. 1, with the valve member in
the cooling mode position and heating mode position, respectively,
of FIGS. 4a and 5b;
[0022] FIGS. 7 and 8a-8c illustrate a variation in the construction
of the coupling disk and the valve member;
[0023] FIG. 9 schematically illustrates an electrical control
system for controlling the rotary motor in the valve assembly to
provide not only change-over from one operation to another, but
also to provide controlled leakage or bleeding from the
high-pressure section to the low-pressure section, in order to
prevent frosting or to defrost without interrupting the operation
of the system;
[0024] FIGS. 10a-10f are views, similar to those of FIGS. 5a and
5b, illustrating how controlled leakage may be produced to prevent
frosting or to defrost;
[0025] FIGS. 11a-11c are views similar to those of FIGS. 10a-10c
illustrating how the valve assembly may be operated to reduce
capacity without interrupting the operation of the system;
[0026] FIGS. 12a-12c corresponds to FIGS. 8a-8c but illustrate a
modification wherein the valve assembly is operated to perform a
control function without interrupting the operation of the
system;
[0027] FIGS. 13 and 14 illustrate two further applications of the
valve assembly of the present invention;
[0028] FIG. 15 is an exploded three-dimensional view illustrating
another preferred form of valve assembly constructed in accordance
with the present invention;
[0029] FIGS. 16a and 16b are three-dimensional views illustrating
the two opposite sides of the valve member in the assembly of FIG.
15;
[0030] FIG. 17a is a bottom view illustrating the control face of
the valve member in the valve assembly of FIG. 15;
[0031] FIG. 17b is a top view illustrating the base-mounted ports
co-operable with the valve member in the valve assembly of FIG.
15;
[0032] FIGS. 18a and 18b illustrate an air-conditioning system
including the valve assembly of FIG. 15, with the valve member in
the cooling mode position and heating mode position
respectively;
[0033] FIGS. 19 and 19a diagrammatically illustrate the valve
assembly of FIG. 15 in its normal cooling position;
[0034] FIGS. 20-23 diagrammatically illustrate the valve assembly
in its cooling mode but at different positions to control a pair of
shunting lines for temperature control purposes;
[0035] FIGS. 20a, 20b-23a, 23b illustrate two optional controls of
the pilot valve in each of the valve positions illustrated in FIGS.
20-23 respectively;
[0036] FIGS. 24-27 and 24a-27b are views corresponding to FIGS.
19-23b but showing the valve member in its heating mode
position;
[0037] FIG. 28 is a top view illustrating the base-mounted ports of
another preferred form of a valve member of a valve assembly
constructed in accordance with the present invention;
[0038] FIGS. 29a and 29b illustrate an air-conditioning system
including the valve assembly of FIG. 28, in the cooling mode
position and heating mode position respectively;
[0039] FIGS. 30a-30c diagrammatically illustrate the valve assembly
of FIG. 28, in its cooling mode at different positions; and
[0040] FIGS. 31a-31c diagrammatically illustrate the valve assembly
of FIG. 28, in its heating mode at different positions.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0041] The valve assembly illustrated in FIGS. 1-6b serves both as
a four-way change-over valve for an air conditioning system, to
operate the system according to either a cooling mode or a heating
mode, and also as a control valve for performing any one of a
number of control functions in either mode. The air conditioning
system, as diagrammatically illustrated in FIGS. 6a and 6b,
includes a compressor 2; an inside heat-exchanger or coil 4 (acting
as an evaporator in the cooling mode); an outside heat-exchanger or
coil 6 (acting as a condenser in the cooling mode), and a valve
assembly 8, having a low pressure port LP.sub.C connected to the
inlet of the compressor 2, and a high-pressure port HP.sub.C
connected to the outlet of the compressor 2. The valve assembly 8
has two further ports HX.sub.I and HX.sub.O to be connected to
ports LP.sub.C and HP.sub.C according to the specific mode of
operation of the air conditioning system. Thus, FIG. 6a illustrates
the cooling mode of operation, wherein port HX.sub.I connects the
low pressure from port LP.sub.C to the inside heat-exchanger 4, and
port HX.sub.O connects the high pressure from port HP.sub.C to the
outside heat-exchanger 6; whereas FIG. 6b illustrates the heating
mode of operation wherein port HX.sub.O connects the low pressure
from port LP.sub.C to the outside heat-exchanger 6, and port
HX.sub.1 connects the high pressure from port HP.sub.C to the
inside heat-exchanger 4.
[0042] The construction of valve assembly 8 is more particularly
illustrated in FIGS. 1-3. It includes a base 10 mounting the four
ports LP.sub.C, HP.sub.C, HX.sub.I, HX.sub.O, which ports are
connected by lines L.sub.1-L.sub.4, respectively, to the compressor
2, inside heat exchanger 4, and outside heat-exchanger 6. Valve
assembly 8 further includes a valve member, generally designated
20, which is rotatable to two operational positions to control the
flow of the gas between the four ports to produce the cooling and
heating modes of operation. Valve member 20 is rotated to its two
operational positions by a drive, generally designated 30, and a
coupling member or disk, generally designated 40.
[0043] Valve member 20, coupling disk 40, and a part of the drive
30, are all enclosed within a housing 50, which is hermetically
sealed to the base 10. The remaining elements of the drive 30 are
enclosed within a second housing 60 secured to the upper end of
housing 50.
[0044] The base 10, which forms the bottom wall of housing 50,
includes a plurality of holes defining the four ports. Port
LP.sub.C, connected by line L.sub.1 to the low pressure inlet of
compressor 2 (FIGS. 6a, 6b), is of the largest cross-sectional
area, and is located centrally of base 10. Port HP.sub.C, connected
by line L.sub.2 to the high pressure outlet of compressor 2, is
located adjacent to the outer periphery of base 10. Port HX.sub.I
connected by line L.sub.3 to the inside heat-exchange 4, and port
HX.sub.O connected by line L.sub.4 to the outside heat-exchanger 6,
are located on the outer periphery of base 10 on opposite sides of
port HP.sub.C.
[0045] Base 10 further includes a stop 11 on its inner face. This
stop cooperates with the valve member 20 to locate that member in
its two operational positions, one producing a cooling mode of
operation, and the other producing a heating mode of operation.
[0046] As shown particularly in FIG. 2, the control face of valve
member 20 (that facing base 10) includes two closed-loop,
concentric rib formations 21, 22. Rib formation 21 is an inner
closed loop centrally of the control face of valve member 20; it
defines an inner low pressure cavity or section 23 in the central
region of that face which is in communication with the low pressure
port LP.sub.C in base 10. Rib formation 22 is an outer, annular
closed loop; it defines with inner rib formation 21, an outer
high-pressure section completely circumscribing the inner
low-pressure section 23 and in communication with the high pressure
port HP.sub.C of base 10. High-pressure section 24 includes two
side portions 24a, 24b, joined together by passageways 24c, 24d, so
as to completely surround the low-pressure section 23.
[0047] For purposes to be described below, a small hole 25 is
formed through the high pressure section 24 of valve member 20, and
a larger hole 26 is formed through its low pressure section 23.
[0048] The opposite face of valve member 20 (shown in FIG. 1) faces
the coupling disk 40. This face includes an outer peripheral wall
27 formed with two cam surfaces 28, which extend radially inwardly
of the valve member at diametrically-opposite locations thereon,
and a slot 29 extending through an arc of approximately 60.degree..
As will be described more particularly below, cam surfaces 28 and
slot 29 cooperate with coupling disk 40 to couple the valve member
20 to the drive via a lost-motion coupling enabling the coupling
disk to be rotated a small amount without rotating the valve
member.
[0049] As indicated earlier, drive 30 is divided into two sections.
One section includes parts enclosed within housing 50 containing
the valve member 20 and the coupling disk 40; whereas the other
section is externally of housing 50 and is enclosed within the
second housing 60 secured to the upper end of housing 50.
[0050] The parts of drive 30, located externally of housing 50 (and
within housing 60) include a motor 31, preferably a step motor,
having a rotary shaft 32 for rotating a disk 33. Disk 33 carries a
pair of permanent magnets 33a, 33b on opposite sides of the disk
and diametrically aligned with its axis of rotation.
[0051] The parts of drive 30 located internally within housing 50
include another disk 34 rotatably mounted on a pin 35 secured to a
rotatable end disk 35a. Disk 34 carries a pair of permanent magnets
34a, 34b diametrically aligned with the axis of rotation of disk
34. Permanent magnets 34a, 34b on disk 34 within housing 50 are of
the same circular configuration as permanent magnets 33a, 33b on
disk 33 within housing 60, and are adapted to be axially aligned
with those magnets to produce a magnetic coupling between the two
disks so that the rotation of disk 33 externally of housing 50
produces a corresponding rotation of disk 34 within housing 50.
[0052] The rotation of disk 34 within housing 50 is transmitted,
via coupling disk 40, to the valve member 20 by means of a drive
gear 36 carried by disk 34, and a step-down transmission 37 coupled
to the coupling disk 40.
[0053] Step-down transmission 37 is of a two-stage planetary-gear
type best seen in FIG. 3. It includes an outer housing 37a formed
with a central opening for receiving drive gear 36 of disk 34, a
ring gear 37b fixed to the inner face of housing 37a, and two
stages 38a,38b of planetary gears cooperable with ring gear 37b.
The first stage 38a includes three planetary gears meshing with
ring gear 37b for rotating a disk 39. Disk 39 is in turn fixed to a
drive gear 39a meshing with the three planetary gears of the second
stage 38b, the latter gears also meshing with ring gear 37b. The
arrangement is such that fast rotation of disk 34 produces a slow
rotation of disk 39, and its planetary gear 38b of the step-down
transmission 37. A projection 50a on the inner face of housing 50,
received within a corresponding recess in the transmission housing
37a, prevents rotation of the transmission housing during the
rotation of the planetary gears.
[0054] Coupling disk 40 is formed with three stems 41 received
within the openings in the three second-stage planetary gears 38b
such that the slow rotation of disk 39 at the output end of the
step-down transmission 37 produces a slow rotation of the coupling
disk 40. This rotary movement of coupling disk 40 is transmitted to
the valve member 20 in a yieldable manner by a pair of
radially-extending, spring-urged coupling pins 42, 43, engaging cam
surfaces 28 on the inner surface of the annular wall 27 of the
valve member 20, as best seen in FIG. 1.
[0055] Coupling disk 40 not only couples the valve member 20 to the
drive, but also cooperates with the large hole 26 for controlling
the fluid pressure applied to the valve member. For the later
purpose, coupling disk 40 is provided with a pair of pilot valve
elements 44,45, each adapted to cover or uncover the large hole 26
according to the position of coupling disk 40 with respect to the
valve member 20. Coupling disk 40 further includes a depending pin
46 received within slot 29 in valve member 20, limiting the
rotation of the coupling disk 40 with respect to the valve
member.
[0056] The change-over operation, wherein the air-conditioning
system is changed-over from a cooling mode (in the summer) to a
heating-mode (in the winter), or vice versa, will now be described
particularly with reference to FIGS. 4a-6b.
[0057] It will be assumed that the valve member 20 is in the
position illustrated in FIG. 5a, which produces a cooling mode of
operation of the air conditioning system as illustrated in FIG. 6a.
In this operational position of the valve member 20, the
low-pressure from port LP.sub.C (connected to the low-pressure side
of compressor 2) is connected to port HX.sub.I leading to the
inside heat-exchanger 4, and the high-pressure from port HP.sub.C
(connected to the high-pressure side of the compressor) is
connected to port HX.sub.O leading to the outside heat-exchanger 6,
thereby producing a cooling mode of operation as shown in FIG.
6a.
[0058] When the valve member is in the operational position of FIG.
5a, the high-pressure appearing in the high-pressure section 24 of
the valve member is transmitted via the small hole 25, acting as a
slow-acting vent, to the opposite side of the valve member (the
side illustrated in FIG. 1). Since the surface area at this side of
the valve member is much larger than the high-pressure surface area
24 at the opposite side of the valve member, this high-pressure
applied via small hole 25 is effective to firmly press valve member
40 against base 10, thereby producing a tight seal against leakage
of gas.
[0059] When it is desired to change the operational position of the
valve member in order to produce a heating mode of operation as
illustrated in FIG. 6b, motor 31 of the drive is energized to
rotate drive disk 33, which as described above, is externally of
housing 50. However, the magnetic coupling produced by permanent
magnets 33a, 33b on the external drive disk 33, and magnets 34a,
34b on the internal drive disk 34, transmits the rotary motion of
motor 31 to the internal drive disk 34 via the step-down
transmission 37 within housing 50. The rotary speed of drive disk
34 is thus reduced by the two-stage planetary gearing transmission
of the step-down transmission 37, to rotate coupling disk 40,
coupled to the second stage planetary gearing by stems 41, at a
relatively low speed. For example, each stage of the two-stage
transmission 37 could produce a step-down ratio of 25:1 so that the
step-down transmission ratio of the complete transmission 37 is
50:1.
[0060] In the initial position of coupling disk 40 (as shown in
FIG. 4a before it begins to rotate), its pin 46 is in one end of
slot 29 (FIG. 1) of the valve member 20. Also, one of its pilot
valve elements 44,45, closes the large hole 26 in the valve member
20, to produce the high-pressure sealing effected by the small hole
25, as described above.
[0061] Immediately upon the initial movement of the coupling disk
40, and before the valve member 20 begins to move, the large hole
26 in the valve member is uncovered by the respective pilot valve
element 44,45. This immediately releases the high pressure pressing
valve member 20 against base 10, thereby enabling the valve member
to be easily rotated by coupling disk 40.
[0062] Rotation-of coupling disk 40 causes the spring-urged pins
42, 43 of the coupling disk to move relative to valve member 20
(FIG. 4b) until they engage cams 28 on the inner surface of
peripheral wall 27 of the valve member and thereby rotate the valve
member to the operational position illustrated in FIG. 5b. This
position is determined by the engagement of stop 11 of base 10 with
the opposite end of the outer high-pressure section 24 of the valve
member. Stop 11 thus prevents further rotation of valve member 20
so that the coupling disk 40 now rotates relative to the valve
member to bring its other pilot valve element 44,45, over the large
hole 26, and thereby to reinstate the high-pressure seal applied to
the valve member by the small hole 25. The valve member is thus now
in the position illustrated in FIG. 5b, determined by pin 46
engaging the opposite end of slot 29, thereby producing a heating
mode of operation of the air conditioning system as illustrated in
FIG. 6b.
[0063] In the illustrated construction, the above-described
change-over operation takes 1.0 to 1.5 seconds. However, may be
slowed down if desired, by controlling the valve motor 31, e.g. to
avoid sudden shocks to the air-conditioning system.
[0064] Whenever it is a desired to make a change-over to a cooling
mode of operation, motor 31 is energized in the reverse direction,
whereupon the same sequence of events as described above occur to
move the valve member 20 back to the position illustrated in FIG.
5a, to thereby produce a cooling mode of operation of the air
conditioning system as illustrated in FIG. 6a.
[0065] FIGS. 7 and 8a-8c illustrate a variation wherein the cam
surfaces 28 are in the form of curved elongated elements 128 having
three cam formations 128a, 128b, 128c. Each cam formation 128
extends for an arc of about 120.degree.. They are separated by
slots 129 each of approximately 60.degree., corresponding to arcute
slots 29 (FIG. 1). In addition, the coupling disk 40 is provided
with two radial ribs 146 which move in slots 129 and thus serve the
same function as pin 46 movable within slot 29 in FIG. 1, as
described above.
[0066] As shown particularly in FIGS. 8a-8c, the spring-urged pins
43 of coupling disk 40 operate with cam surfaces 128a, 128b, 128c
of the two cam elements 128 in the same manner as described above,
first to release the high sealing pressure applied to valve member
20, then to rotate the valve member to its new operational
position, and then to restore the high-sealing pressure applied to
the valve member. Thus, when the valve member is precisely in an
operational position, pilot valve element 44 of the coupling disk,
being precisely over large opening 26 in the valve member (FIG.
8a), is closed, such that the high-sealing pressure is applied to
the valve member as describe above. When the valve member is to be
moved to a new operational position, coupling disk 40 is first
rotated to displace pilot valve element 44 away from opening 26
(FIGS. 8b, 8c), thereby releasing the high sealing pressure, such
that when pins 42, 43 engage the middle cam surface 128b, the
coupling disk will rotate the valve member to its new operational
position. It is stopped in this operational position by pin 11 as
described above, whereupon coupling disk 40 will continue to move,
overcoming the middle cam surface 128b until it reaches the end cam
surface 128c; at that position its other pilot valve element 45 now
covers large opening 26 to thereby restore the high sealing
pressure to the valve member.
[0067] An important characteristic of the described valve assembly
is that it automatically maintains the valve member 20 very close
to the base 10, separated by a thin air cushion, all the time the
valve member is not precisely in one of its two operational
positions. This close spacing is automatically self-regulated all
the time the valve member is not precisely in one of its
operational positions by leakage from the circular high pressure
section 24 at the ribbed face of valve member 20 to the opposite
face of the valve member. Thus, should valve member 20 tend to tilt
or separate from base 10 at any point around the circumference of
the valve member, the so-produced space will cause the high
pressure from the annular high pressure section 24 to be applied
via this space to the opposite face of valve member 20, thereby
restoring the valve member to its close position with the base.
[0068] This regulated action of the valve member 20 thus produces a
thin air cushion, which facilitates the change-over operation for
changing from one operational mode to another. While this air
cushion produces some leakage, it is relatively small such that the
high-pressure section of the valve member is still substantially
isolated from the low-pressure section sufficiently to enable the
valve assembly to serve also as a control valve and to perform many
important control functions within an operational mode. Described
below, for purposes of example, are anti-frosting or defrosting
control, and output-reduction control, both of which may be
performed by the described valve assembly in either of the two
operational modes of the air-conditioning system and without
interrupting the operation of the air-conditioning system.
[0069] FIG. 9 diagramatically illustrates an electrical circuit for
controlling the valve motor 31 of the valve assembly both for a
mode change-over operation, and also for a control operation within
one of the modes. The system illustrated in FIG. 9 includes a
control circuit CC for controlling the valve motor 31; a mode
selector MS for operating the system according to the cooling mode
(in the summer), or the heating mode (in the winter); a defrost
selector DS for producing an anti-frosting or defrosting control
operation within one of the two operational modes; and an output
selector OS for controlling the output of the system without
interrupting the operation of the system. Also illustrated in FIG.
9 is a temperature sensor TS which senses temperature, e.g., the
outside ambient temperature, and produces an output to the control
circuit CC automatically controlling valve motor 31 in order to
prevent frost, or to defrost, in a very efficient manner and
without interrupting the operation of the system.
[0070] The described valve assembly enables the air-conditioning
system to be operated in order to prevent frosting, to defrost, or
to provide other temperature controls, both in the cooling mode and
the heating mode. The manner in which this is accomplished is
illustrated in FIGS. 10a-10f.
[0071] In FIGS. 10a-10f, the ports LP.sub.C, HP.sub.C, HX.sub.I,
HX.sub.O are correspondingly marked as in FIGS. 5a and 5b. However,
the rib formation 21, which defines the inner low-pressure region
23 and the outer, annular high-pressure region 24, is not of even
thickness as illustrated in FIG. 2, but rather of varied thickness
as shown by the section lines 121 in FIGS. 10a-10f. This is
preferable particularly for the output-reduction control to be
described below.
[0072] FIG. 10a illustrates the position of the rotary valve member
120 with respect to the four ports in the base (10, FIG. 1) to
produce a cooling mode of operation as described above particularly
with respect to FIG. 5a. Whenever it may be desired to prevent
frosting, to defrost, or to provide other temperature controls,
valve member 120 may be moved, via the coupling disk (40, FIG. 1)
to produce a controlled leakage or bleeding between the
high-pressure outer region 124 produced by the high-pressure port
HP.sub.C, and the low-pressure central region 123 coupled to the
low-pressure port LP.sub.C, corresponding to the amount of leakage
desired. The leakage not only influences the pressure of the gas in
each region but also influences the temperature in each region.
[0073] FIGS. 10b-10e illustrate how this leakage may be increased,
as desired, until the second operational position, namely the
heating mode, is reached as illustrated in FIG. 10f. It will be
appreciated that the greater the leakage, the greater will be the
anti-frosting or defrosting results.
[0074] This leakage to prevent frosting (or to defrost) may be
automatically controlled in response to the outside ambient
temperature by temperature sensor TS illustrated in FIG. 9. For
example, when the system is operating according to the cooling
mode, and the outside ambient temperature drops, this will be
sensed by temperature sensor TS to automatically control, via
circuit CC, the valve motor 31 to produce a controlled leakage of
high temperature gas to the region to be warned in order to prevent
frosting or to defrost.
[0075] This control may be a periodic one, wherein valve motor 31
(FIG. 1) would be controlled to periodically move the valve member
to one of the positions illustrated in FIGS. 10b-10e and then back
to its normal operating position. This periodic control of leakage
may be effected by periodically controlling the amplitude of the
leakage (per FIGS. 10b-10e), the time interval of each period of
leakage, and/or the frequency at which the leakage is effected.
Such a control, may also be continuous, wherein a continuous
leakage could be provided having a magnitude depending on the
output of the temperature sensor to prevent frosting. This leakage
can also be produced manually by operating defrost selector button
DS (FIG. 9), or automatically in response to temperature. Such an
anti-frosting or de-frosting operation is easily permitted by the
described valve assembly without interrupting the overall operation
of the system since: (1) the valve motor 31 can be precisely
controlled by the control circuit CC; (2) since the valve member
may be easily rotated to any desired position with respect to base
10; and (3) the regulated light contact, or very close spacing, of
the valve member with respect to the base, whenever the valve
member is not in one of its operational positions, substantially
isolates the high-pressure section from the low-pressure section
sufficiently to permit this type of control.
[0076] An anti-frost or defrost control as described above provides
a number of important advantages. It enables the air-conditioning
system to be operated for maximum efficiency without danger of
frosting. It also permits the system to be operated continuously,
and not to be interrupted or reversed, thereby saving considerable
energy, maximizing the utilization of the air-conditioning system,
and avoiding undesirable interruption of the compressor.
[0077] FIGS. 11a-11c illustrate how the novel valve assembly may be
modified to produce a desired output-reduction in the
air-conditioning system without interrupting its operation. For
example, air-conditioning systems are normally designed for maximum
efficiency at a predetermined output, and if the needed output is
to be reduced, e.g. because of a decrease in the space to be heated
or cooled, it is usually necessary to interrupt the operation of
the system. However, such an operation of a normal air-conditioning
system reduces its overall efficiency, wastes considerable energy,
accelerates wear, etc., because of frequent interruptions of the
system.
[0078] The valve assembly of the present invention permits the
output of the air-conditioning system, both in the cooling mode and
in the heating mode, to be reduced as desired without interrupting
the operation of the system. This can be done, for example, by
controlling the valve motor 31 to produce a controlled reduction in
the effective cross-sectional area of the low-pressure port LPC
exposed to the heat-exchanger connected to it. Thus, FIG. 11a
illustrates the valve member 120 in a cooling-mode position wherein
its rib 121 fully opens the low-pressure port LPC exposed to the
inside heat-exchanger port HXI, thereby producing 100% suction;
FIG. 11b illustrates the valve member position wherein rib 121
covers about 25% of the cross-sectional area of the low-pressure
port LPC, thereby producing about 75% suction; and FIG. 11c
illustrates the valve member position wherein rib 121 covers about
75% of the cross-section area of the low-pressure port LP.sub.C
thereby producing about 25% suction.
[0079] Such an output-reduction operation may also be performed
periodically, continuously, or as required by the motor control
circuit CC controlling valve motor 31, as described above with
respect to the temperature control, and does not require
interrupting the operation of the air-conditioning system.
[0080] FIGS. 12a-12c are views corresponding to those of FIGS.
8a-8c but including slight modification of the valve member 120
with respect to the location of the cam elements 128, engageable by
the spring-urged pins 42, 43, to better assure that the coupling
disk 40 will not move to a position causing its pilot valve
elements 44, 45, to cover the low-pressure large hole 26 in the
valve member except when the valve member is precisely in one of
its two operational positions. Thus, the spring-urged pins 42, 43,
engage the cam element high points 128a, 128c only after a pilot
valve element 44, 45 closes the low-pressure port 26 to reapply the
high sealing pressure against the valve member (FIG. 12c).
[0081] The illustrated valve assembly may be used for performing
other control functions within either of the two operational modes.
For example, the valve motor 31 may be controlled merely to
periodically move coupling disk 40 sufficiently to cause its pilot
valve elements 44 or 45 to unseat large hole 26, and thereby to
bleed-off a small amount of high-pressure, without actually moving
valve member 20. Such an operation may be desired to perform a
small hot-gas bypass control as often as may be necessary.
[0082] The illustrated valve assembly may also be used for
controlling a different number of ports. FIG. 13 illustrates an
example wherein the valve assembly includes only three ports,
namely a low-pressure port P.sub.1, a high pressure point P.sub.2,
and a further port P.sub.3 to selectively receive either the low
pressure from port P.sub.1 or the high pressure from port
P.sub.2.
[0083] FIG. 14 illustrates a valve assembly including five ports,
of which ports P.sub.1-P.sub.4 are the four ports described above
(e.g. FIG. 2), the fifth port P.sub.5 being provided to selectively
apply high-pressure to the evaporator, for example, for defrosting
or other control purposes.
[0084] FIG. 15 illustrates a valve assembly very similar to that
described above with respect to FIGS. 1-3, and therefore in order
to facilitate understanding, corresponding parts have been
identified by the same reference numerals. The main differences
between the two structures appear in the base, and in the valve
member, identified as 210 and 220, respectively, in FIG. 15. FIG.
16a more particularly illustrates the side of valve member 220
facing the coupling disk 40; FIGS. 16b and 17a more particularly
illustrate the side of the valve member facing the base 210; and
FIG. 17b more particularly illustrates the base 210 cooperable with
the valve member 220.
[0085] Base 210 mounts the same four ports LP.sub.C, HP.sub.C,
HX.sub.I, HX.sub.O as in FIG. 1, which ports are connected by lines
(L.sub.1-L.sub.4, FIG. 1) to the compressor 2, the inside heat
exchanger 4, and the outside heat exchanger 6 (FIGS. 18a, 18b).
Base 210 also includes a stop 211, corresponding to stop 11 in
FIGS. 1-3 but of smaller diameter. Stop 211 is straddled on its
opposite sides by two additional ports, namely: a shunting port
S.sub.I connecting a shunt line 212 (FIGS. 18a, 18b) to the inside
heat exchanger 4, and a shunting port S.sub.O connecting a second
shunt line 213 to the outside heat exchanger 6.
[0086] The control face of valve member 220, as illustrated
particularly in FIG. 17a, also includes an inner closed-loop rib
221 defining a central low-pressure section 223, and an outer
annular rib 222 defining, between it and rib 221, an outer, annular
high-pressure section 224 enclosing the inner low-pressure section
223. The two closed-loop ribs 221 and 222 are specially shaped to
cooperate with the ports in the base 210, as will be described more
particularly below.
[0087] As in the previously-described embodiments, valve member 220
also includes a small hole 225 connecting the high pressure section
224 to the opposite face of the valve member for applying high
pressure thereto; and a larger hole 226 leading from the
low-pressure section 223, and co-operable with a pilot valve 244 on
coupling disk 40, for releasing the high pressure when it is
desired to change-over the valve from one operational position to
another.
[0088] The side of valve member 220 facing coupling disk 40 is
somewhat different in structure from that described above. As shown
particularly in FIG. 16a, this side of valve member 220 is formed
with a peripheral rib 227a, 227b on each of its opposite sides,
each formed with a central recess 228. The two peripheral ribs
extend for 120.degree. to define a 60.degree. slot 229a, 229b, at
each of its opposite sides.
[0089] As will be described below, recesses 228, serve as detents
for releasably receiving the two spring-urged pins 42, 43 of the
coupling disk 4 when the coupling disk is precisely in position
wherein its pilot valve 244 closes the large hole 226 in valve
member 220; whereas slot 229a, 229b cooperate with radial
projections 246a, 246b in the coupling disk 40 to rotate the valve
member 220 to any desired position after the high-pressure applied
to the valve member has been released by opening the pilot valve
hole 226.
[0090] FIGS. 18a and 18b illustrate the position of the valve
member 220 with respect to the base 210 for producing a cooling
mode of operation and a heating mode of operation, respectively,
corresponding to FIGS. 6a and 6b in the earlier described
embodiments. The valve illustrated in FIG. 15 may also be
controlled in the manner described above with respect to FIGS.
10a-10f to produce any desired leakage control from the high
pressure section to the low pressure section of the control valve
for temperature control purposes, or as described above with
respect to FIGS. 11a-11c to control the output of the system by
controlling the cross-sectional area of the low-pressure port
LP.sub.C exposed to the respective heat exchanger.
[0091] The valve illustrated in FIG. 15, however, may be operated
to perform further control functions. Thus, the provision of the
two shunting ports S.sub.I and S.sub.O in the base 210 permits the
valve also to control the shunting of gas to selected locations in
the system via the shunting lines 212, 213 for temperature control
purposes; also, the lost-motion construction of the side of valve
member 220 facing the coupling disk 40 enables the motor also to be
used for selectively opening or closing the pilot valve PV (element
244 moveable with respect to opening 226) at any position of the
valve member (i.e. in either of the two mode positions, or any
intermediate position between them), e.g. to exert a moderate
control of temperature or pressure whenever, and as often as deemed
necessary, without actually moving the valve member 220.
[0092] The foregoing operations are more particularly illustrated
in FIGS. 19-24.
[0093] FIG. 19 illustrates a straight cooling mode, wherein the low
pressure port LP.sub.C is coupled to the inside heat exchanger port
HX.sub.I, and the high pressure port HP.sub.C is connected to the
outside heat exchanger port HX.sub.O. In the position illustrated
in FIG. 19, neither of the shunts S.sub.1, S.sub.o is active. FIG.
19a illustrates the normal closed position of the pilot valve 244,
i.e., closing hole 226, such that high pressure is applied via hole
225 to the opposite side of the valve member 220.
[0094] FIG. 20 illustrates the valve member 220 moved slightly
(clockwise) to partially expose shunt port SI to the high pressure
cavity 224, to thereby shunt a portion of the high pressure gas to
the inside heat-exchanger 4. This may be desired, for example, to
provide a small hot-gas bypass in order to prevent freezing of the
inside heat-exchanger. The valve member also slightly reduces the
cross-sectional area of the inside heat-exchanger port HXI exposed
to the low pressure, but this is not significant here.
[0095] FIGS. 20a, 20b illustrate that, in the valve position of
FIG. 20, the pilot valve 244 may also be closed (FIG. 20a), or open
(FIG. 20b) in order to perform a small hot-gas bypass control, if
so desired, without interrupting the operation of the
compressor.
[0096] FIGS. 21, 21a, and 21b, illustrate similar conditions as
FIGS. 20, 20a, 20b, but with the full cross-section of the shunting
port S.sub.1 exposed to the high pressure section.
[0097] FIGS. 22, 22a, 22b illustrate the condition wherein both
shunting ports S.sub.I, S.sub.O are blocked, but a smaller
cross-sectional area of the inside heat-exchanger port HX.sub.I is
exposed to the low pressure section, thereby further reducing the
output of the air-conditioning system; and FIGS. 23, 23a and 23b
illustrate similar conditions but even with a further reduction in
the air-conditioning output system. In both cases, the
cross-sectional area of outside heat-exchanger port HX.sub.O
exposed to the light pressure is also reduced, which thereby
reduces the volume of the gas, and therefore this work load on the
compressor.
[0098] FIGS. 24-27 illustrate similar controls when the
air-conditioning system is in the heating mode.
[0099] Reference is now made to FIGS. 28a-28b, 29a-29b, 30a-30c and
31a-31, which illustrate another preferred embodiment of a valve
member forming part of a valve assembly, generally designated 300,
constructed in accordance with the present invention.
[0100] FIG. 28a is a top view illustrating the base-mounted ports,
generally designated 302 of a valve member 304 shown in FIG. 28b.
FIGS. 29a and 29b illustrate an air-conditioning system including
the valve assembly 300 of FIGS. 28a-28b, in the cooling mode
position and heating mode position respectively;
[0101] FIGS. 30a-30c diagrammatically illustrate the valve member
304, in its cooling mode at different positions. FIGS. 31a-31c
diagrammatically illustrate the valve member 304, in its heating
mode at different positions.
[0102] Valve member 304 is similar to valve member 210 (shown in
FIG. 17b) and may be used in place of the valve member 210 within
the valve assembly of FIG. 15. Elements having similar functions
are similarly designated and will not be further described.
[0103] Base 302 mounts the same four ports LP.sub.C, HP.sub.C,
HX.sub.I, HX.sub.O as in FIG. 15, which ports are connected by
lines (similar to lines L.sub.1-L.sub.4 of FIG. 1) to the
compressor 2, the inside heat exchanger 4, and the outside heat
exchanger 6 (FIGS. 29a, 29b). Base 302 also includes a stop 211,
which is straddled on its opposite sides by two expansion ports,
referenced S.sub.2 and S.sub.3 (FIGS. 29a, 29b). Port S.sub.2
connects a shunt line 212 to the inside heat exchanger 4, and port
S.sub.3 connects a second shunt line 213 to the outside heat
exchanger 6. S.sub.2 and S.sub.3 are also connected to an expansion
valve 315 (similar to element 244 of FIG. 15). In addition, two
additional ports, referenced S.sub.4 and S.sub.5 (FIGS. 29a, 29b)
are provided. Port S.sub.4 connects a third shunt line 314 to the
inside heat exchanger 4, and port S.sub.5 connects a fourth shunt
line 316 to the outside heat exchanger 6.
[0104] The control face of valve member 304, as illustrated
particularly in FIG. 28b, includes a loop rib 306 defining a
central low-pressure section 308, and an outer, annular
high-pressure section 310 and 312 enclosing the inner low-pressure
section 308. The loop rib 306 is specially shaped to cooperate with
the ports in the base 302, as will be described more particularly
below.
[0105] As in the previously-described embodiments, valve member 304
also includes a small hole (similar to 225 in FIG. 16a) connecting
the high pressure section 310 to the opposite face of the valve
member for applying high pressure thereto; and a larger hole
(similar to 226 in FIG. 16a) leading from the low-pressure section
308, and co-operable with a pilot valve 244 on coupling disk 40
(see FIG. 15), for releasing the high pressure when it is desired
to change-over the valve from one operational position to
another.
[0106] The sides of valve member 304 facing coupling disk 40 are
similar to that of valve member 220 but having a structure
configured to valve member 304, and will not be described
further.
[0107] FIGS. 29a and 29b illustrate the position of the valve
member 304 with respect to the base 302 for producing a cooling
mode of operation and a heating mode of operation, respectively,
corresponding to FIGS. 18a and 18b in the earlier described
embodiments. The control of the valve assembly 300 with the
replacement of valve member 304 and the base ports 302 (in place of
valve member 220 and the base ports 210 of FIG. 15) is similar to
the control operation described hereinabove.
[0108] The valve assembly 300 containing valve member 304 in
conjunction with base 302 may be operated to perform several
control functions. As described above with reference to FIGS.
18-27, the lost-motion construction of the side of valve member 304
facing the coupling disk 40 enables the motor also to be used for
selectively opening or closing the expansion valve 315 at any
position of the valve member (i.e. in either of the two mode
positions, or any intermediate position between them), e.g. to
exert a moderate control of temperature or pressure whenever, and
as often as deemed necessary.
[0109] In addition, valve assembly 300 is provided with two
additional ports S.sub.4 and S.sub.5 in the base 302 which permit
the valve to also control the shunting of gas via the shunting
lines 314, 316 for temperature control purposes.
[0110] The foregoing cooling and heating operations are more
particularly illustrated in FIGS. 30a-30c and 31a-31c,
respectively.
[0111] FIG. 30a illustrates the cooling mode, wherein the low
pressure port LP.sub.C is coupled to the inside heat exchanger port
HX.sub.I, and the high pressure port HP.sub.C is connected to the
outside heat exchanger port HX.sub.O. In the position illustrated
in FIG. 30a, neither of the ports S.sub.4, S.sub.5 are active but
the expansion valve 315 is fully opened, with shunts S.sub.2,
S.sub.3 open allowing the flow from shunt line 213 via expansion
valve 315 and shunt line 212.
[0112] FIG. 30b illustrates the valve member 304 moved slightly
(clockwise) to partially close shunt port S.sub.2 to the high
pressure cavity 224.
[0113] FIG. 30c illustrates the operation of the hot gas by-pass.
In this case, port S.sub.4 is partly opened allowing the hot gases
to be diverted along line 314.
[0114] FIGS. 31a-31c illustrate similar controls when the
air-conditioning system is in the heating mode.
[0115] In the heating position illustrated in FIG. 31a, neither of
the ports S.sub.4, S.sub.5 are active but the expansion valve 315
is fully opened (shunts S.sub.2, S.sub.3 open) allowing the flow
from shunt line 212 via expansion valve 315 and shunt line 213.
[0116] FIG. 31b illustrates the valve member 304 moved slightly
(counter clockwise) to partially close shunt port S.sub.3 to the
high pressure cavity 224.
[0117] FIG. 31c illustrates the operation of the hot gas by-pass in
the heating mode, wherein port S.sub.5 is partly opened (s4 is
closed) allowing the hot gases to be diverted along line 316.
[0118] It will thus be seen that the novel valve assembly as
described above may be used, not only as a change-over valve for
changing from one operational mode to the other, but also as a
control valve to perform a large number of controls in either of
the operational modes. Many features of the present invention
contribute to this advantageous result, particularly the
construction of the valve member and the provision of the annular
high-pressure section around and enclosing the low-pressure
section, which self-regulates the valve member to produce a thin
air cushion facilitating moving the valve member while maintain its
control face, sufficiently close to the base to substantially
isolate the high-pressure section from the low-pressure section in
any position of the valve member. This construction of the valve
member produces, in effect, variable gates which can variably
control leakage or shunting from one pressure section to another
(e.g. for temperature control purposes) or can variably control the
cross-sectional area of the low-pressure section exposed to the
heat exchanger (e.g. for output control purposes), both without
interrupting the operation of the air-conditioner. Further, the
control of the pilot valve in any position of the valve member also
enables a small hot-gas bypass to be effected whenever desired and
in any position of the valve member. Finally, using a motor drive,
particularly a step-motor, enables very precise control, both
automatically and manually, of the valve member to perform any of
the above-described functions.
[0119] Therefore, while the invention has been described with
respect to several preferred embodiments, it will be appreciated
that these are set forth merely for purposes of example, and that
many other variations of the invention may be made. For example,
the invention can be used in manually-driven valve assemblies, or
in valve assemblies for applications other than in air-conditioning
systems. Certain features of the invention could be used without
other features. For example, one or more of the above described
control functions, e.g. leakage or shunting control, output control
or pilot valve control, could be implemented in other change-over
valve constructions.
[0120] It will be appreciated by persons skilled in the art that
the present invention is not limited by what has been particularly
shown and described herein above. Rather the scope of the invention
is defined by the claims which follow:
* * * * *