U.S. patent number RE40,511 [Application Number 11/509,055] was granted by the patent office on 2008-09-23 for rotary disc valve.
This patent grant is currently assigned to Mego Afek Industrial Measuring Instruments. Invention is credited to Aharon Weiss.
United States Patent |
RE40,511 |
Weiss |
September 23, 2008 |
Rotary disc valve
Abstract
A multi-port rotary disc valve comprising a stator with a
plurality of fluid flow ports and a rotary distributor with a
plurality of channels arranged in a channel pattern. The channels
are adapted to connect the ports between them and/or to the
environment in a plurality of predetermined combinations, each
combination being associated with an angular position of the rotary
distributor with respect to the stator. The succession of
combinations performed during a full or partial unidirectional turn
of the rotary distributor consitute a predetermined sequence. The
rotary distributor comprises a rotor and a mask mounted movably
thereon, the rotor and the mask accommodating the plurality of
channels. The mask is adapted to change the channel pattern by
changing its position with respect to the rotor, thereby enabling
the rotary disc valve to perform different predetermined sequences
corresponding to different positions of the mask.
Inventors: |
Weiss; Aharon (Misgav,
IL) |
Assignee: |
Mego Afek Industrial Measuring
Instruments (Doar Afek, IL)
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Family
ID: |
31187991 |
Appl.
No.: |
11/509,055 |
Filed: |
August 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10225435 |
Aug 22, 2002 |
06779557 |
Aug 24, 2004 |
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Current U.S.
Class: |
137/624.13;
137/624.18; 137/625.11 |
Current CPC
Class: |
F16K
11/074 (20130101); Y10T 137/86501 (20150401); Y10T
137/86405 (20150401); Y10T 137/86445 (20150401); Y10T
137/86389 (20150401) |
Current International
Class: |
F15B
13/042 (20060101) |
Field of
Search: |
;137/624.13,624.18,625.11,627.5,625.18,625.46 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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01-145474 |
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Jul 1989 |
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JP |
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WO 99 02905 |
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Jan 1999 |
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WO |
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Primary Examiner: Lee; Kevin L
Attorney, Agent or Firm: Browdy and Neimark
Claims
What is claimed is:
1. A multi-port rotary disc valve comprising a stator with a
plurality of fluid flow ports and a rotary distributor with a
plurality of channels arranged in a channel pattern, .Iadd.said
rotary distributor comprising a rotor and a mask mounted movably
thereon, said mask being, on the one hand, movable with respect to
the rotor and, on the other hand, being adapted for rotation
together with the rotor as a single body, the rotor and the mask
accommodating said plurality of channels; .Iaddend.said channels
being adapted to connect said ports between them and/or to the
environment in a plurality of predetermined combinations, each
combination being associated with an angular position of the rotary
distributor with respect to the stator, a succession of such
combinations .Iadd.being .Iaddend.performed during a full or
partial unidirectional turn of said .[.rotary distributor.].
.Iadd.single body .Iaddend.constituting a predetermined
sequence.[.; said rotary distributor comprising a rotor and a mask
mounted movably thereon, the rotor and the mask accommodating said
plurality of channels, and.]. .Iadd., .Iaddend.said mask being
adapted to change said channel pattern by changing its position
with respect to said rotor, thereby enabling said disc valve to
perform different predetermined sequences corresponding to
different positions of the mask.
2. A rotary disc valve according to claim 1, wherein said mask is
movable with respect to said rotor by way of rotation.
3. A rotary disc valve according to claim 2, wherein the rotation
of said rotary distributor and the rotation of said mask are
performed around the same axis.
4. A rotary disc valve according to claim 3, wherein said rotor and
said mask are coaxial and co-rotatable discs.
5. A rotary disc valve according to claim 1, wherein said rotary
distributor is rotatable by means of an electric drive.
6. A rotary disc valve according to claim 1, wherein said mask is
movable by means of an electric drive.
7. A rotary disc valve according to claim 4, wherein said rotary
distributor is rotatable relative to said stator in a first
direction only.
8. A rotary disc valve according to claim 7, wherein said mask disc
is rotatable relative to said rotor disc in a second direction
only, contrary to said first direction.
9. A rotary disc valve according to claim 8, wherein the rotation
of said mask disc in said second direction only is provided by a
ratchet and pawl mechanism.
10. A rotary disc valve according to claim 8, further comprising a
single reversible electric drive whereby said rot distributor
rotates only when said drive rotates in said first direction and
said mask disc rotates relative to said rotor disc only when said
drive rotates in said second direction.
11. A rotary disc valve according to claim 4, wherein said rotor
disc has a first face sealingly contacting with a face of said
stator, and the connections between said stator ports and said
rotary distributor channels are performed via said first face.
12. A rotary disc valve according to claim 11, wherein said rotor
disc has a second face sealingly contacting with a face of said
mask disc, at least part of said plurality of channels exit at said
second face, and said mask disc changes said channel pattern by
switching connections between said part of channels exiting at the
second face.
13. A rotary disc valve according to claim 12, wherein said
plurality of fluid flow ports comprises a central inlet port and N
outlet ports disposed around said central port.
14. A rotary disc valve according to claim 13, wherein said rotor
disc has a feed channel so configured that, during one turn of the
rotary distributor, said feed channel successively connects said
central inlet port to each one of said N outlet ports.
15. A rotary disc valve according to, claim 14, wherein said rotor
disc has N through windows connecting said first face to said
second face, so configured that, in a predetermined angular
position A of the rotary distributor with respect to said stator,
said N through windows match said N outlet ports.
16. A rotary disc valve according to claim 15, wherein said mask
disc has a group exhaust channel so configured that, in a
predetermined angular position B of said mask disc with respect to
said rotor disc, said group exhaust channel is connected to all
said N through windows of the rotor disc and is connectable to a
source of vacuum, thereby enabling a group evacuation of any
volumes connected to said N outlet ports of the stator, provided
the positions A and B are attained.
17. A rotary disc valve according to claim 16, wherein said source
of vacuum is an entry port of a compressor or pump.
18. A rotary disc valve according to claim 16, wherein said stator
has a vacuum port connectable to said source of vacuum, and said
rotor disc has an exhaust port so configured that, in said position
B of the mask disc, it is connected to said group exhaust channel,
and in said position A of the rotary distributor, it matches said
vacuum port.
19. A rotary disc valve according to claim 14, wherein said
plurality of fluid flow ports further comprises a number of exhaust
ports connected to the ambient atmosphere and disposed at least in
part intermediate to said N outlet ports so that said feed channel,
during a turn of said rotary distributor, can communicate with one
of said exhaust ports while not communicating with any of said N
outlet ports.
20. A rotary disc valve according to claim 14, wherein said stator
has N through pressure openings each disposed adjacent to one of
said N outlet ports, and a pressure channel connecting said
pressure openings to a pressure outlet connectable to a pressure
sensor, said rotor disc has a bypass channel so configured as to be
able to connect, when rotated, anyone of said N outlet ports to the
corresponding adjacent pressure opening while keeping the rest
pressure openings stopped, thereby enabling measurement of pressure
P.sub.C in a volume connected to said anyone outlet port by means
of said sensor.
21. A rotary disc valve according to claim 20, wherein said bypass
channel is disposed behind said feed channel with respect to said
first direction of rotation so that said bypass channel is
connected to outlet port No. n when said feed channel is between
outlet port No. n+1 and outlet port No. n+2 where n is an ordinal
number of one of said N outlet ports, n increasing in said first
direction.
22. A rotary disc valve according to claim 21, constituting a part
of a computerized system for inflating and deflating in cycles N
cells connected to said N outlet ports, by rotating said rotary
distributor, said system further comprising a sensor to measure the
pressure P.sub.0 in said central inlet port and said pressure
sensor to measure the pressure P.sub.C in said pressure outlet,
said system being programmable to terminate the inflation of one of
said N cells at a predetermined instant value of the pressure
P.sub.0 in order to obtain a target established pressure P.sub.E in
said one cell, and said system being adapted to correct said
instant value in a next cycle if the measured pressure P.sub.C in a
current cycle is different from the target pressure P.sub.E.
23. A rotary disc valve according to claim 1, wherein said stator
comprises two plates, each plate accommodating part of said fluid
flow ports, with said rotary distributor sandwiched between said
two plates.
.Iadd.24. A multi-port rotary disc valve comprising a stator with a
plurality of fluid flow ports and a rotary distributor with a
plurality of channels arranged in a channel pattern, said channels
being adapted to connect said ports between them and/or to the
environment in a plurality of predetermined combinations, each
combination being associated with an angular position of the rotary
distributor with respect to the stator, a succession of such
combinations performed during a full or partial turn of said rotary
distributor constituting a predetermined sequence; said rotary
distributor comprising a rotor and a mask, the rotor and the mask
accommodating said plurality of channels, and said mask being
mounted movably on the rotor to move between positions with respect
thereto, in which the mask covers at least a part of the channels
accommodated by the rotor, to connect at least a part of said ports
therebetween, and positions in which the mask allows at least a
part of the channels to communicate with the environment, thereby
enabling said disc valve to perform different predetermined
sequences corresponding to different positions of the
mask..Iaddend.
Description
FIELD OF THE INVENTION
This invention relates to rotary disc valves for feeding fluid flow
and/or pressure to a plurality of ports, in particular to valves
performing a predetermined cycle of feeding operations, such as,
for example, numerous cyclical inflating and deflating a plurality
of pressure cells in an inflatable device.
BACKGROUND OF THE INVENTION
A rotary disc valve for inflating and deflating pressure cells in a
therapeutic sleeve is disclosed in U.S. Pat. No. 5,014,681,
incorporated herein by reference. This rotary disc valve comprises
two discs: a stator disc with fluid flow ports connectable to a
compressor and to the pressure cells, and a rotary distributor
disc, the two discs contacting sealingly along a planar interfacing
surface perpendicular to the axis of rotation. The ports of the
stator disc open at the interfacing surface. The rotary distributor
disc has a plurality of U-channels and through-going windows also
opened at the interfacing surface. The channels and windows are
configured so that during rotation of the rotary distributor disc,
the compressor flow is successively directed, through the
appropriate ports, to inflate the corresponding pressure cells,
which are then successively opened to die atmosphere, all this
following a predetermined sequence.
JP 01145474 discloses a rotary disc valve with a similar function
where the stator comprises two discs fixed with respect to each
other, the stator discs slidingly contacting a rotor distributor
disc disposed therebetween. The rotor disc has U-channels and
through holes connecting the ports of the stator in various
combinations during one turn of the rotor distributor disc.
U.S. Pat. No. 4,614,205 discloses a multiport rotary disc valve
with a similar function of simultaneous interconnection of a
plurality of conduits in accordance with a predetermined cycle. The
stator and the rotary distributor in this rotary valve are
assemblies each comprised of two parallel plates or discs. The
rotary assembly is sandwiched between two parallel plates of the
stator assembly. Crossover pipes extend between the rotor plates to
form either U-channels or through-passages similar to the
above-cited designs.
The known rotary disc valves are capable of performing one
predetermined cycle (sequence) of connections between the stator
ports. The connections may be varied in time by controlling the
rotational velocity and position of the rotor, but their order is
determined by the pattern of the channels in the rotor and the
stator.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a
multi-port rotary disc valve comprising a stator with a plurality
of fluid flow ports and a rotary distributor with a plurality of
channels arranged in a channel pattern. The channels are adapted to
connect the ports between them and/or to the environment in a
plurality of predetermined combinations, each combination being
associated with an angular position of the rotary distributor with
respect to the stator. A succession of such combinations performed
during a full or partial unidirectional turn of the rotary
distributor constitute a predetermined sequence. The rotary
distributor comprises a rotor and a mask mounted movably thereon,
accommodating the plurality of channels. The mask is adapted to
change the channel pattern by changing its position with respect to
the rotor, thereby enabling the disc valve to perform different
predetermined sequences corresponding to different positions of the
mask.
In a preferred embodiment the mask and the rotor are coaxial and
co-rotatable discs driven by a reversible controllable electric
drive. The rotary distributor is mounted rotatably relative to the
stator in a first direction only, while the mask disc is mounted
rotatably relative to the rotor disc in a second direction only,
contrary to said first direction. Thereby, the rotary distributor
rotates only when electric drive rotates in the first direction and
the mask disc rotates relative to the rotor disc only when the
drive rotates in the second direction.
In a further embodiment of the rotary disc valve, the rotor disc
has two faces, at least part of the rotary distributor channels
connecting them. The first face sealingly contacts with a face of
the stator, the connections between the stator ports and the rotary
distributor channels being performed via this face. The second face
sealingly contacts with a face of the mask disc, and the mask disc
changes the channel pattern by switching connections between those
channels that exit at the second face.
The rotary disc valve used for inflating and deflating N cells
comprises a central inlet port and N outlet ports disposed around
the central port. The rotor disc has a feed channel configured so
that, during one turn of the rotary distributor, it successively
connects the central inlet port to each one of the outlet
ports.
The rotary disc valve is also adapted for group exhaust of all N
inflated cells. For this purpose, the rotor disc has N through
windows connecting the first face to the second face, configured so
that, in a predetermined angular position A of the rotary
distributor with respect to the stator, the N through windows match
the N outlet ports. The mask disc has a group exhaust channel
configured so that, in a predetermined angular position B of the
mask disc with respect to the rotor disc, the group exhaust channel
is connected to all the through windows of the rotor disc. The
group exhaust channel is her connectable to a source of vacuum such
as the entry of a compressor or pump, thereby enabling a group
evacuation of any volumes connected to the N outlet ports of the
stator, provided the positions A and B are attained
simultaneously.
Preferably, the rotary disc valve is adapted to work as a part of a
computerized system for inflating and deflating in cycles N cells
connected to the N outlet ports. The stator of the rotary disc
valve has N through pressure openings each disposed adjacent to one
of the outlet ports, and a pressure channel connecting the pressure
openings to a pressure outlet. The rotor disc has a bypass channel
configured so as to be able to connect, when rotated, anyone of the
outlet ports to the corresponding adjacent pressure opening while
keeping the rest pressure openings stopped, thereby enabling the
measurement of pressure P.sub.C in a volume connected to anyone
outlet port. Preferably, the bypass channel is disposed behind the
feed channel with respect to the first direction of rotation, so
that the bypass channel is connected to outlet port No. n when, the
feed channel is between outlet port No. n+1 and outlet port No.
n+2, where n is an ordinal number of an outlet port, n increasing
in the first direction. The system comprises a sensor to measure
the pressure P.sub.0 in the central inlet port, and a sensor to
measure the pressure P.sub.C in the pressure outlet. The system is
programmed to terminate the inflation of a given cell at a
predetermined instant value of the pressure P.sub.0 in order to
obtain a target established pressure P.sub.E in that cell, and the
system is adapted to correct this instant value in a next cycle if
the measured pressure P.sub.C in a current cycle is different from
the target pressure P.sub.E.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to understand the invention and to see how it may be
carried out in practice, a preferred embodiment will now be
described, by way of non-limiting example only, with reference to
the accompanying drawings, in which:
FIG. 1 is an exploded view of a rotary disc valve according to the
present invention;
FIGS. 2A, 2B, and 2C are, respectively, lower, upper and
cross-sectional views of the stator disc shown in FIG. 1;
FIGS. 3A, 3B, and 3C are, respectively, lower, upper and
cross-sectional views of the rotor disc shown in FIG. 1; and
FIGS. 4A, 4B, and 4C are, respectively, lower, upper and
cross-sectional views of the mask disc shown in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, a multi-port rotary disc valve 10
according to the present invention is shown for use, for example,
with an inflatable device having a plurality of pressure cells. One
example of such inflatable device will be used in the explanations,
without any limitations to the scope of the invention. The device
is a therapeutic massage sleeve with N annular cells embracing a
human's limb (not shown here) as described in the incorporated U.S.
Pat. No. 5,014, 681. The annular cells are close to each other or
even slightly overlapping, and they need to be cyclically inflated
or deflated in different sequences depending on the therapeutic
procedure.
The rotary disc valve 10 comprises a housing 12, a stator disc 14,
a rotor disc 16, a mask disc 20, a coupling disc 22, and a drive
motor 24, all adapted for coaxial assembly along axis 2 of the
valve.
The housing 12 is a massive plate with a circular recess 26
accommodating the stator 14, with a plurality of N outlet windows
28 disposed in a fan-like manner around the axis 2 at a
predetermined uniform angular distance .DELTA..alpha. from each
other. The outlet windows 28 are connected by individual channels
(not seen) to outlet ports 30. In operation, the outlet ports 30
are connected by pipes to the inflatable cells of an inflatable
device, such as a massage sleeve (not shown). The housing 12 has
also a central inlet port 32 connectable to a source of pressurized
fluid such as the discharge of an air compressor (not shown), an
exhaust port 34, and a vacuum port 33 connectable to a source of
vacuum such as the entry of an air compressor. The housing also has
a channel 35 for measuring the air pressure of the inlet flow and a
channel 36 for measuring the air pressure in inflated cells, as
will be explained in more detail below.
With reference also to FIGS. 2A, 2B and 2C, the stator 14 is a disc
with a wide axial opening 38 and with a plurality of various
through windows, recesses and channels. In particular, the stator
14 has N through outlet windows 40 matching the outlet windows 28
of the housing, and N through pressure openings 46 each disposed
adjacent to an outlet window 40. At the lower side of the stator
that faces the housing 12 (FIG. 2A), there are the exit sides of
the N outlet windows 40, an arcuate vacuum channel 42
concentrically embracing the windows 40, and an arcuate cell
pressure channel 44 concentric with the vacuum channel 42
internally connected to the N pressure openings 46. The end 47 of
the cell pressure channel 44 matches the inlet of the measurement
channel 36 when the stator is mounted in the housing. An exhaust
recess 48 located to match the exhaust port 34 of the housing 12 is
in fluid communication with an exhaust window 50 at the upper side
of the stator (FIG. 2B), though a slit 51. Also at the upper side
of the stator, which faces the rotor 16, are the entrance sides of
the outlet windows 40, and a plurality of recesses 52 disposed in a
fan-like manner between the outlet windows 40. The recesses 52 are
displaced farther from the disc axis than the windows 40 and are
internally connected to the exhaust channel 42 on the lower side of
the disc. The pressure openings 46 connect the cell pressure
channel 44 at the lower surface of the stator to the stator upper
surface facing the rotor 16. A long arcuate recess 54 has a wide
opening 56 adapted to match the vacuum, port 33 in the housing 12
and is in fluid communication with the exhaust channel 42 through a
slit 55. An extension 58 of the recess 54 is connected thereto by a
narrow passage 60.
The stator 16 is sealingly mounted to the housing 12, in the recess
50 thereof, and operators as one integral body with the
housing.
With reference to FIGS. 3A, 3B and 3C, the rotor disc 16 has a
blind central recess 62 at the lower side which faces the stator 14
(FIG. 3A). At the same side, the rotor has a radial feed channel 64
extending from the recess 62 to a radius suitable to cover the
outlet windows 40 on the stator 14 when the valve is assembled. A
plurality of N+3 windows 66 are disposed in fan-like manner at one
side of the feed channel 64. The windows 66 are at an angular
distance .DELTA..alpha. from each other and from the feed channel
64 so as to be able to match the windows 40 on the stator 16 when
the valve is assembled. A group of three windows 68A, 68B, and 68C
similar to the windows 66 are located at the other side of the feed
channel 64. A group of N openings 70 are disposed between the
windows 66 farther from the axis 2 of the valve than the outer edge
of the windows 66. A single bypass recess 72 is placed in one and a
half angular steps .DELTA..alpha. from the feed channel 64. The
recess 72 has such radial extent that it can cover and establish
fluid communication between a window 40 and a corresponding
pressure opening 46 on the stator, when the valve is assembled
(shown also in FIG. 2B, in broken line). The rotor has also a wide
window 74 completing the arc of windows 66 and 68 to a full ring. A
wide exhaust port 76 is disposed on the rotor farther from the axis
2 than the openings 70, and is configured to match the recess 54 on
the stator. On the circumference of the rotor disc 16, there is a
plurality of inclined teeth 78 constituting part of a ratchet
mechanism, adapted for engagement with the coupling disc 22 (FIG.
1).
With reference to FIGS. 4A, 45 and 4C, the mask disc 20 has a wide
arcuate window 80 with radial extent similar to that of the windows
66 on the rotor 16 and angular extent suitable to cover N windows
66, when the mask disc 20 is mounted on the rotor 16. The mask disc
20 further has a group of three adjacent exhaust windows 82A, 82B
and 82C, and one remote exhaust window 84, each adapted to match
the exhaust port 76 on the rotor 16. At the lower side of the mask
facing the rotor 16, there is a group exhaust recess 86, shaped
similarly to, and disposed adjacent the group of windows 82. The
group exhaust recess 86 communicates with an arcuate exhaust
channel 88 which has angular extent, radial position and width
suitable to match the openings 70 and to connect them all via the
exhaust recess 86, to the exhaust port 76 on the rotor, when the
mask disc 20 is mounted on the rotor 16. On the circumference of
the mask disc 20, there are three pairs of teeth 90 for coupling
the mask disc to the coupling disc 22 (FIG. 1).
With reference to FIG. 1, the coupling disc 22 is a thin disc with
three straight teeth 92 matching the teeth 90 on the mask disc 20,
and a spring pawl 94. The coupling disc is fixed to the shaft (not
seen) of the electric motor 24.
The electric motor 24 is reversible and controllable by angular
velocity and angular coordinate. The control system (not shown)
comprises inter alia a sensor 96 for the angular position of the
rotor disc 16, and a sensor 98 for the angular position of the mask
disc 20.
In assembled condition, the rotor 16 sits on the stator 14 and is
rotatably connected to the housing 12 by means of a one-way bearing
18 allowing rotation of the rotor only in direction A. The mask
disc 20 sits rotatably on the rotor 16. The coupling disc 22
engages the mask disc 20 by means of the teeth 90 and 92 for
rotation of the mask in any direction. At the same time, the spring
pawl 94 of the coupling disc 22 engages the teeth 78 of the rotor
disc 16 forming a ratchet mechanism allowing the mask 20 to rotate
with respect to the rotor 16 only in direction B. The stator 14,
the rotor 16, and the mask 20 are pressed to each other for air
tightness by a spring means (not shown). Thus, when the motor 24
rotates in direction A, the mask disc 20 and the rotor 16 rotate
together, as a single body, and constitute a rotary distributor
interacting with the stator 14 to feed the air coming from the air
compressor to the outlet ports 30, in a predetermined sequence.
This manner of rotation is called "operational mode". When the
motor rotates in direction B, the rotor 16 stands still with
respect to the stator 14 while the mask disc 20 slips relative to
the rotor 16 to change its angular position relative to the rotor,
thus making a different rotary distributor capable of performing a
different predetermined sequence. This manner of rotation is called
"setup mode". Thereby, the inventive rotary disc valve can perform
the function of several conventional multi-port disc values.
A number of predetermined sequences are illustrated below by way of
examples only.
Sequence A: Sequential Inflation--simultaneous deflation.
The mask disc 20 is rotated in direction B relative to the rotor 16
to a position where the exhaust window 84 matches the exhaust port
76, and at the same time the wide arcuate window 80 of the mask
covers all N windows 66 of the rotor. The initial position of the
rotor 16 with respect to the stator 14 is with the feed channel 64
over the exhaust window 50. This is a stand-by or idle mode where
the pressurized air from the compressor comes via the central inlet
port 32 and the axial opening 38 to the recess 62 and the feed
channel 64, and leaves the rotary valve through the exhaust window
50 and the exhaust port 34.
As the rotor 16 starts to rotate in direction A, the feed channel
64 moves over the nearest outlet window 40.sub.1 which is connected
to the first annular cell and it starts to inflate. After a
predetermined time, or after reaching a predetermined pressure in
the first cell, the rotor moves on and the feed channel 64 now
matches the nearest recess 52.sub.1 which is connected to the
exhaust channel 42, while the fluid communication with the first
cell is stopped. This is also a stand-by mode. After a
predetermined time, the rotor moves on and the feed channel matches
the next outlet window 40.sub.2 to inflate the next cell. Thus, all
N cells are successively inflated until the feed channel reaches
the last outlet window 40.sub.N. After a predetermined time, the
rotor makes about 1/2 turn so that all N outlet windows 40 match
the windows 66 and communicate with the atmosphere via the window
80 on the mask. Thereby, the cells are deflated simultaneously and
the sequence A is completed.
Sequence B: Sequential Inflation--sequential deflation.
The mask disc 20 is rotated in direction B relative to the rotor 16
to a position where the exhaust window 82A matches the exhaust port
76, and at the same time the wide arcuate window 80 of the mask
covers the windows 68A, 68B and 68C of the rotor. The initial
position of the rotor 16 with respect to the stator 14 is with the
feed channel 64 over the exhaust window 50, as above.
As the rotor 16 starts to rotate in direction A, the feed channel
64 moves over the nearest outlet window 40.sub.1 which is connected
to the first annular cell, and it inflates. Then, the rotor moves
on and the feed channel 64 matches the nearest recess 52.sub.1
(stand-by mode). After a predetermined time, the rotor moves on and
the feed channel 64 matches the next outlet window 40.sub.2 to
inflate the next cell. At the same tine, the window 68A of the
rotor matches the first outlet window 40.sub.1 and the first cell
releases its pressure to the atmosphere through the window 80.
Thus, all N cells are successively inflated and each one is
deflated when the next cell is inflated.
If, alternatively, the exhaust window 82B of the mask is fixed
opposite the exhaust port 76 of the rotor, then the window 80 of
the mask will cover only windows 68B and 68C of the rotor. Thus,
the outlet window 40.sub.1 will be opened to the atmosphere only
when the window 68B matches it, which will happen when the feed
channel 64 reaches the outlet window 40.sub.3. In a similar manner,
when the exhaust window 82C of the mask is fixed opposite the
exhaust port 76, the outlet window 40.sub.1 opens to the atmosphere
only when the window 68C matches it and this happens when the feed
channel 64 reaches the outlet window 40.sub.4. Thereby, the three
exhaust windows 82A, 82B and 82C of the mask, with the cooperation
of the three windows 68A, 68B and 68C of the rotor, provide for
three sequences B each characterized by different delay of the cell
deflation.
Sequence C: Active suction.
The mask disc 20 is rotated in direction B relative to the rotor 16
to a position where the group exhaust recess 86 matches the exhaust
port 76. The rotor 16 is now rotated, together with the mask disc
20, in direction A with respect to the stator 14 to a position
where the feed channel 64 is over the exhaust window 50, in
stand-by mode as above. The exhaust port 76 now is positioned over
the arcuate recess 54 and is in fluid communication with the vacuum
port 33 which is connected to the compressor entry. The arcuate
exhaust channel 88 covers all openings 70 of the rotor which, in
their turn, match the inlet windows 40. Thereby, the compressor
suction provides for the rapid deflation of the massage sleeve
cells.
The rotary disc valve of the present invention may be
advantageously used in a computerized system for inflating and
deflating in cycles a plurality of cells connected to the outlet
ports, for example in the therapeutic sleeve shown in U.S. Pat. No.
5,014,681. The system is programmable to terminate the inflation of
each cell when a predetermined instant pressure P.sub.0 is reached
(i.e. by moving the feed channel 64 to stand-by position or to the
next cell). However, the instant pressure P.sub.0 during the
inflation is transient and even if the system terminates the
inflation at P.sub.0=P.sub.E, the establishe pressure P.sub.C in
the cell at a short time may turn out different from the target
pressure P.sub.E. Another factor that may affect the established
pressure P.sub.C in the cell is the inflation of the next adjacent
cell, especially when the cells overlap. The computerized system
that controls the inflation-deflation process needs to measure the
actual established pressure P.sub.C in the cell in order to compare
it to the target pressure P.sub.E and to try to minimize the
difference .DELTA.P=P.sub.E-P.sub.C when the next turn to inflate
the same cell comes, by shifting the predetermined pressure P.sub.0
for this particular cell.
The rotary disc valve facilities the above process of precise
achievement of target established pressure P.sub.E in the inflated
cells. The instant pressure P.sub.0 is measured at the central
inlet port of the rotary valve, by means of a pressure sensor
connected to the channel 35. The measurement of the established
cell pressure P.sub.C, after the next cell is inflated, is provided
by means of the bypass recess 72 on the rotor, which is located
one-and-half angular steps .DELTA..alpha. behind the feed channel
64 with respect to rotation direction A. When the feed channel 64
has inflated two successive cells via the respective outlet windows
40 and is in stand-by position halfway to a third outlet window 40,
then the bypass recess 72 covers the first outlet window 40 and a
corresponding opening 46 on the stator. Thereby, fluid
communication is provided between the first inflated cell and the
cell pressure channel 44 that is connected to a pressure sensor via
the measurement channel 36, and the established cell pressure
P.sub.C is measured.
Although a description of specific embodiments has been presented,
it is contemplated that various changes could be made without
deviating from the scope of the present invention. For example, the
mask may be movable with respect to the rotor not only by way of
rotation but in any other way providing commutation of the rotor
distributor channels; the mask may comprise plural movable parts;
the rotor and the mask may be driven by other means than electric
motor; the rotary distributor may be driven by one motor and the
mask may be driven by another motor; the discs may contact
therebetween along a conical or other surface of rotation, etc.
Also, the stator may comprise two discs with inlet or outlet
windows at either side of the rotary distributor in a manner
similar to U.S. Pat. No. 4,614,205 or to JP 01145474, which are
incorporated herein by reference.
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