U.S. patent application number 09/891153 was filed with the patent office on 2001-11-01 for two out of three voting solenoid arrangement.
Invention is credited to Summers, Angela E., Zachary, Brian A..
Application Number | 20010035214 09/891153 |
Document ID | / |
Family ID | 26926905 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010035214 |
Kind Code |
A1 |
Zachary, Brian A. ; et
al. |
November 1, 2001 |
Two out of three voting solenoid arrangement
Abstract
A binary voting solenoid arrangement 10 is provided which
operates in a "2 out of 3" manner to provide relatively high
safety, low spurious tripping and a relatively low installation
cost, while also enabling on-line testing of each solenoid
individually without process interruption. Solenoid arrangements
10, 10' and 10" are preferably used in a three-way configuration,
while solenoid 10'" may be used in a two-way configuration.
Inventors: |
Zachary, Brian A.; (Alvin,
TX) ; Summers, Angela E.; (Houston, TX) |
Correspondence
Address: |
Richard L. Sampson
SAMPSON & ASSOCIATES, P.C.
50 Congress Street
Boston
MA
02109
US
|
Family ID: |
26926905 |
Appl. No.: |
09/891153 |
Filed: |
June 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09891153 |
Jun 25, 2001 |
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09790261 |
Feb 21, 2001 |
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09790261 |
Feb 21, 2001 |
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09638311 |
Aug 14, 2000 |
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09638311 |
Aug 14, 2000 |
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09233406 |
Jan 19, 1999 |
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6155282 |
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Current U.S.
Class: |
137/557 |
Current CPC
Class: |
Y10T 137/0318 20150401;
Y10T 137/8326 20150401; Y10T 137/0447 20150401; G05B 9/03
20130101 |
Class at
Publication: |
137/557 |
International
Class: |
F16K 037/00 |
Claims
Having thus described the invention, what is claimed is:
1. A binary voting solenoid arrangement adapted to selectively
couple a fluid supply with a fluid receiver, said voting solenoid
arrangement comprising: first, second and third solenoid valves
each having a plurality of ports; a plurality of inlet and outlet
pathways each extending from a respective port of one of said
solenoid valves to a port of another of said solenoid valves,
wherein said solenoid valves are disposed in fluid communication
with one another; a by-pass valve having first and second open and
closed positions, said by-pass valve being adapted to selectively
couple the fluid source with the fluid receiver while bypassing
said first, second and third solenoid valves, said by-pass valve
including a five port, four way by-pass valve; a single port of
said bypass valve being the fluid receiver; each of said first,
second, and third solenoid valves and said by-pass valve being
alternatively actuatable between first and second open and closed
positions; wherein actuation of at least any two of said first,
second and third solenoid valves alternately couples and de-couples
the fluid supply with said fluid receiver.
2. The voting solenoid arrangement of claim 1 wherein said by-pass
valve includes a pair of common ports which are selectively coupled
in fluid communication with three other ports, said alternate
actuation including alternately coupling said pair of common ports
with a distinct two of said three other ports.
3. The voting solenoid arrangement of claim 1 wherein said by-pass
valve is manually operable.
4. The voting solenoid arrangement of claim 1 wherein said by-pass
valve is included with said first, second and third solenoid valves
in a manifold.
5. The voting solenoid arrangement of claim 1 wherein actuation of
said by-pass valve alternately couples and de-couples said fluid
supply with the fluid receiver.
6. The voting solenoid arrangement of claim 1 wherein: a single
port of said by-pass valve is coupled in fluid communication with
the fluid supply; each of said first and second solenoid valves are
coupled with said by-pass valve such that each of said first and
second solenoid valves are in fluid communication with the fluid
supply when said by-pass valve is in said first position; said
second solenoid valve is coupled in fluid communication with said
third solenoid valve; and said third solenoid valve is coupled with
said by-pass valve such that said third solenoid valve is in fluid
communication with the fluid receiver when said by-pass valve is in
said first position.
7. The voting solenoid arrangement of claim 6 wherein: each of said
first, second and third solenoid valves further comprise a
plurality of upstream ports and a plurality of downstream ports;
said by-pass valve is coupled to an upstream port of each of said
first and second solenoid valves; at least two of said plurality of
downstream ports of said second solenoid valve are respectively
coupled in fluid communication along discrete pathways with at
least two of said plurality of upstream ports of said third
solenoid valve; and a downstream port of said third solenoid valve
is coupled to said by-pass valve.
8. The voting solenoid arrangement of claim 7, wherein: said first,
second and third solenoid valves each comprise five port, four way
solenoid valves having a pair of common ports which are selectively
coupled in fluid communication with three other ports, said
alternate actuation including alternately coupling said pair of
common ports with a distinct two of said three other ports.
9. The voting solenoid arrangement of claim 8, wherein: said
by-pass valve is coupled to one of said other ports of each of said
first and second solenoid valves; each of said pair of common ports
of said second solenoid valve are respectively coupled along
discrete pathways with two of said three other ports of said third
solenoid valve; and one of said common ports of said third solenoid
valve is coupled to said by-pass valve.
10. The voting solenoid arrangement of claim 1, wherein said first,
second and third solenoid valves each comprise five port, four way
solenoid valves.
11. The voting solenoid arrangement of claim 10, wherein said five
port, four way solenoid valves further comprise a pair of common
ports which are selectively coupled in fluid communication with
three other ports, said alternate actuation including alternately
coupling said pair of common ports with a distinct two of said
three other ports.
12. The voting solenoid arrangement of claim 1 wherein the fluid
comprises at least one of air and hydraulic fluid.
13. The voting solenoid arrangement of claim 1, wherein the fluid
is coupled between the fluid supply and the fluid receiver when any
two of said first, second and third solenoid valves are disposed in
said first state.
14. The voting solenoid arrangement of claim 13, wherein any one of
said first, second and third solenoid valves is adapted for being
disposed in said second state without de-coupling the fluid supply
from the fluid receiver.
15. The voting solenoid arrangement of claim 1, further comprising
a plurality of pressure sensors operatively associated with said
first, second and third solenoid valves and with said by-pass valve
to indicate the state thereof.
16. The voting solenoid arrangement of claim 15, wherein said
plurality of pressure sensors is adapted to indicate the state of
each of said first, second and third solenoid valves when the fluid
supply is coupled to the fluid receiver.
17. The voting solenoid arrangement of claim 15, wherein said
first, second and third solenoid valves are adapted for being
individually tested without de-coupling the fluid supply from the
fluid receiver, said plurality of pressure sensors being adapted to
indicate the state of the individual solenoid valve being
tested.
18. A binary voting solenoid arrangement adapted to selectively
couple a fluid supply with a fluid receiver, said voting solenoid
arrangement comprising: first, second and third solenoid valves
each including at least two common ports and three other ports,
wherein said at least two common ports are selectively coupled in
fluid communication with a distinct two of three other ports; a
manually operated by-pass valve having first and second open and
closed positions, said by-pass valve being adapted to selectively
couple the fluid source with the fluid receiver while bypassing
said first, second and third solenoid valves, said by-pass valve
including a five port, four way by-pass valve; a single port of
said bypass valve being the fluid receiver; a single port of said
by-pass valve being coupled in fluid communication with the fluid
supply; each of said first and second solenoid valves being coupled
with said by-pass valve such that each of said first and second
solenoid valves are in fluid communication with the fluid supply
when said by-pass valve is in said first position; said second
solenoid valve being coupled in fluid communication with said third
solenoid valve; and said third solenoid valve being coupled with
said by-pass valve such that said third solenoid valve is in fluid
communication with the fluid receiver when said by-pass valve is in
said first position; and each of said first, second and third
solenoid valves being alternatively actuatable between first and
second open and closed positions; wherein actuation of at least any
two of said first, second and third solenoid valves alternately
couples and de-couples the fluid supply with the fluid
receiver.
31. A method for selectively coupling a fluid supply with a fluid
receiver, the method comprising: providing first, second and third
solenoid valves each having a plurality of ports, and each being
alternately actuatable between open and closed positions; and
providing a plurality of inlet and outlet pathways each extending
from a respective port of one of said solenoid valves to a port of
another of said solenoid valves, wherein said solenoid valves are
disposed in fluid communication with one another, said first
solenoid valve in fluid communication with said second solenoid
valve and said second solenoid valve in fluid communication with
said third solenoid valve; providing a five port, four way by-pass
valve; and coupling one port of said by-pass valve to the fluid
supply and another port of said bypass valve to the fluid receiver
such that actuation of said by-pass valve selectively couples the
fluid source with the fluid receiver while bypassing said first,
second and third solenoid valves; wherein actuation of any two of
said first, second and third solenoid valves alternately couples
and de-couples the fluid supply with the fluid receiver.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 09/790,261, entitled Two Out Of Three Voting Solenoid
Arrangement, filed Feb. 21, 2001, which is a continuation-in-part
of U.S. patent application Ser. No. 09/638,311, entitled Two Out Of
Three Voting Solenoid Arrangement, filed Aug. 14, 2000, which is a
Continuation of U.S. Pat. No. 6,155,282, entitled Two Out Of Three
Voting Solenoid Arrangement, filed Jan. 19, 1999.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to solenoid valves, and more
particularly to an arrangement of solenoid valves in
instrumentation and process control systems of a plant.
[0004] 2. Background Information
[0005] Modern process or manufacturing plants contain innumerable
operating components. These components are tied together to form
systems controlled by instrumentation and control systems
containing sensors and controllers. The instrumentation and control
systems on such plants not only serve to control the functions of
the various components in order to achieve the desired process
conditions, but they also provide the facility to safely modify or
discontinue the operation of all or a portion of the plant's
systems in order to avoid an unsafe situation or condition.
[0006] Safety systems or configurations require routine testing in
order to verify that they continue to properly perform the
functions for which they were intended. From an operational and
economic point of view, they also should not modify or discontinue
the operation of the plant system unnecessarily. One of the means
by which such safety systems function is by the securing or
diverting of the supply of a certain process fluid or the supply of
motive power to a plant system or component of a plant system.
[0007] One of the means by which these safety functions may be
accomplished is through the use of solenoid operated valves. In
operation, the solenoid valves of such systems serve to isolate
and/or vent off the fluid or pneumatic source from the system when
the solenoid valve changes state or position (e.g. when the valve
is de-energized by switches or process monitoring sensors coupled
thereto). The plant system and any system controlled thereby is
then placed in a configuration designated for safety.
[0008] In many cases, the operation of individual solenoid valves
may not be tested without actually tripping the system and
undesirably modifying or discontinuing the operation of the plant
system. Moreover, various configurations available for actuating
safety shutoff valves generally require a trade-off between
competing characteristics of safety and spurious trip rate.
[0009] For example, a "1 out of 2" voting solenoid valve
arrangement generates a process modification (i.e. shutdown) when
at least one of the two solenoids changes state. Such a
configuration provides relatively high safety, with an associated
relatively high spurious trip rate (i.e., a single faulty valve or
sensor may generate a false trip).
[0010] A "2 out of 2" voting solenoid valve arrangement requires
actuation of two solenoid valves in order to trigger a modification
of the plant system. This configuration has a relatively low
spurious trip rate, since both solenoids must fail or otherwise
change state to generate a spurious trip. However, the solenoid
valves of this arrangement must be tested frequently to insure
safety, since failure of only a single solenoid valve may
effectively prevent the system from shutting down, etc.
[0011] Quad voting solenoids provide a balance of safety and
reliability, however the quad configuration utilizes four solenoids
in a relatively complex arrangement that tends to be difficult to
install, test, and maintain.
[0012] Thus, there exists a need for a voting solenoid
configuration which combines the features of relatively high safety
with relatively low spurious trip rate and does not require the
plant system to be shut down during testing.
SUMMARY OF THE INVENTION
[0013] According to an embodiment of this invention, a binary
voting solenoid arrangement adapted to selectively couple a fluid
supply with a fluid receiver, the voting solenoid arrangement
including first, second and third solenoid valves each having a
plurality of ports. A plurality of inlet and outlet pathways each
extend from a respective port of one of the solenoid valves to a
port of another of the solenoid valves, so that the solenoid valves
are disposed in fluid communication with one another. The
arrangement includes a by-pass valve having first and second open
and closed positions, the by-pass valve being configured to
selectively couple the fluid supply with the fluid receiver while
bypassing the first, second and third solenoid valves. The by-pass
valve includes a five port, four way by-pass valve, with a single
port of the bypass valve being the fluid receiver. Each of said
first, second, and third solenoid valves and said by-pass valve are
alternatively actuatable between first and second open and closed
positions, so that actuation of at least any two of the first,
second and third solenoid valves alternately couples and de-couples
the fluid supply with said fluid receiver.
[0014] Another aspect of the present invention includes a method
for selectively coupling a fluid supply with a fluid receiver, the
method including providing first, second and third solenoid valves
each having a plurality of ports, and each being alternately
actuatable between open and closed positions; and providing a
plurality of inlet and outlet pathways each extending from a
respective port of one of the solenoid valves to a port of another
of the solenoid valves, so that the solenoid valves are disposed in
fluid communication with one another, with the first solenoid valve
being in fluid communication with the second solenoid valve and the
second solenoid valve being in fluid communication with the third
solenoid valve. The method also includes providing a five port,
four way by-pass valve, and coupling one port of the by-pass valve
to the fluid supply and another port of the bypass valve to the
fluid receiver so that actuation of the by-pass valve selectively
couples the fluid source with the fluid receiver while bypassing
the first, second and third solenoid valves, wherein actuation of
any two of the first, second and third solenoid valves alternately
couples and de-couples the fluid supply with the fluid
receiver.
[0015] According to still another aspect, this invention includes a
binary voting solenoid arrangement configured to selectively couple
a fluid supply with a fluid receiver. The voting solenoid
arrangement includes first, second and third solenoid valves each
including at least two common ports and three other ports, in which
the two common ports are selectively coupled in fluid communication
with a distinct two of three other ports. The arrangement also
includes a manually operated by-pass valve having first and second
open and closed positions, the by-pass valve being configured to
selectively couple the fluid source with the fluid receiver while
bypassing the first, second and third solenoid valves, the by-pass
valve including a five port, four way by-pass valve. A single port
of the bypass valve is the fluid receiver, and a single port of the
by-pass valve is couplable in fluid communication with the fluid
supply. Each of the first and second solenoid valves are coupled
with the by-pass valve so that each of the first and second
solenoid valves are in fluid communication with the fluid supply
when the by-pass valve is in the first position. The second
solenoid valve is coupled in fluid communication with the third
solenoid valve; and the third solenoid valve is coupled with the
by-pass valve so that the third solenoid valve is in fluid
communication with the fluid receiver when the by-pass valve is in
the first position. Each of the first, second and third solenoid
valves are alternatively actuatable between first and second open
and closed positions, wherein actuation of at least any two of the
first, second and third solenoid valves alternately couples and
de-couples the fluid supply with the fluid receiver.
[0016] The above and other features and advantages of this
invention will be more readily apparent from a reading of the
following detailed description of various aspects of the invention
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic circuit diagram of a fluid safety
system incorporating the solenoid arrangement of the present
invention;
[0018] FIG. 2 is a truth table for individual actuation of the
solenoids of the solenoid arrangement of FIG. 1;
[0019] FIG. 3 is a view similar to FIG. 1, of an alternate
embodiment of the present invention;
[0020] FIG. 4 is a view similar to FIG. 2, of the alternate
embodiment of FIG. 3; and
[0021] FIG. 5 is a schematic circuit diagram of another alternate
embodiment of the present invention.
DETAILED DESCRIPTION
[0022] Referring to the figures set forth in the accompanying
Drawings, the illustrative embodiments of the present invention
will be described in detail hereinbelow. For clarity of exposition,
like features shown in the accompanying Drawings shall be indicated
with like reference numerals and similar features as shown in
alternate embodiments in the Drawings shall be indicated with
similar reference numerals.
[0023] Referring to FIGS. 1-4, the apparatus constructed according
to the principles of the present invention is shown. The present
invention includes a voting solenoid arrangement 10 which operates
in a "2 out of 3" manner to provide relatively high safety, low
spurious tripping and a relatively low installation cost, while
also enabling on-line testing of each solenoid individually without
process interruption. Solenoid arrangement 10 is preferably
manifolded (not shown), to facilitate maintenance on any detected
failure, and to simplify installation and replacement.
[0024] Referring now to FIG. 1, the apparatus of the present
invention will be more thoroughly described. As shown, the voting
solenoid arrangement 10 of the present invention is adapted to
selectively channel air from an air supply 12 ultimately to a valve
or other fluid receiver 14. Valve 14 may be a component of a plant
process, instrumentation or control system. Any suitable fluid may
be utilized, such as hydraulic fluid, water, etc. In a preferred
embodiment, the solenoid arrangement 10 is pneumatic. The fluid is
fed from air supply 12 to solenoid arrangement 10 through conduit
16 and subsequently flows from solenoid arrangement 10 to valve 14
through conduit 18. Voting solenoid arrangement 10 includes three
discreet solenoid valves 20, 22 and 24, any two of which must be
actuated to start or stop air flow from conduit 16 to conduit 18.
As shown, in a preferred embodiment, solenoid valves 20, 22 and 24
are bidirectional 5-port 4-way solenoid valves. These valves are
thus operable with fluid flowing therethrough in either of two
directions along one of two pairs of alternate pathways. For
example, valve 20 includes a pair of common ports 202 and 204 which
are selectively and alternately coupled with a distinct two of
three other ports by alternate fluid pathways 26 and 27. As shown,
in a first state (i.e., energized), pathways 26 of valve 20 couple
ports 202 and 204 to ports 201 and 205. When actuated to its second
(i.e. de-energized) state, pathways 27 (shown in phantom) couple
the common ports 202 and 204 with ports 201 and 203. Fluid
communication or coupling operation of the pathways 26 and 27 are
mutually exclusive, so that when pathways 26 are open, pathways 27
are closed and vice versa.
[0025] Conduit 16 supplies air simultaneously to port 201 of valve
20 and to port 225 of solenoid valve 22. When the valves 20, 22 and
24 are in their normal or energized states, the passageways 26 are
open and passageways 27 are closed. Alternatively, when the valves
are disposed in their de-energized states, passageways 26 are
closed and the alternate passageways 27 are open. When the valves
are in their normal state air will flow from conduit 16 through
port 201 of valve 20 to port 202 and to conduit 28 which in turn
supplies the air to port 221 of valve 22. The air then travels
through the valve 22 to port 222 and on through conduit 30 to port
241 of valve 24. Simultaneously, air from conduit 16 is fed to
conduit 32, to port 225 of valve 22, through the valve to port 224,
then to port 245 of valve 24 through conduit 34. The solenoid valve
24 then passes the air to port 244, to conduit 18 and ultimately to
valve 14.
[0026] In the event of a change of state of any single valve 20, 22
or 24, such as in the event of a valve failure or a valve test, air
will continue to pass through the solenoid arrangement 10 to the
valve 14. For example, in the event solenoid valve 24 is
de-energized, although air flowing through the valve from conduit
34 will be shut off, passageways 27 will open to permit air from
conduit 30 to be fed from port 241 to port 244, and thus to conduit
18, to maintain air flow to valve 14. Air will only cease flowing
to conduit 18 in the event one of the other solenoid valves 20 or
22 is also de-energized. In this regard, if valve 22 is
de-energized in addition to valve 24, air being fed to the valve 22
at port 221 would flow to port 224 (instead of port 222) and thus
through conduit 34 to port 245 of the valve 24. Since valve 24 is
de-energized, passageway 26 thereof is closed and accordingly, air
does not flow to conduit 18. Similarly, if both valves 20 and 24
are de-energized, air that would otherwise flow to port 241 of
valve 24 from valve 22, is effectively shutoff at valve 20 due to
the closing of the passageway 26 between ports 201 and 202
thereof.
[0027] In the event that only valve 22 is de-energized, air supply
arriving at port 225 through conduit 32 at port 225 is effectively
shut off. However, air being supplied by conduit 28 to port 221
will be shunted to port 224 and thus through conduit 34 to port 245
of valve 24, where it will be fed through the valve to conduit 18.
In the event that both valve 22 and valve 20 are de-energized, the
air flow to valve 22 through conduit 28 will be effectively shut
off by the action of valve 20 which when de-energized, shunts the
air supply at port 201 to port 204.
[0028] As also shown, a series of pressure valves 40, 42 and 44 are
provided to monitor the actual state of solenoid valves 20, 22 and
24. In a preferred embodiment, pressure switch 40 is disposed in
pressure sensing contact with port 204 of solenoid valve 20.
Pressure switch 42 is disposed in pressure sensing contact with
conduit 30 and pressure switch 44 is disposed in pressure sensing
contact with port 242 of valve 24. The pressure switches 42 and 44
include electrical contacts (not shown) which are alternately open
and closed in response to absence and presence of pressure thereat
(i.e., normally open). Pressure switch 40 includes electrical
contacts (not shown) which are alternately closed and opened in
response to absence and presence of pressure thereat (i.e. normally
closed).
[0029] In the embodiment shown, when only solenoid valve 20 is
de-energized, air pressure from port 201 is shunted to port 204
which serves to open the contacts of switch 40. Simultaneously, the
contacts of pressure switches 42 and 44 are opened due to lack of
pressure thereat. Upon reset or energization of solenoid valve 20,
the contacts of pressure switches 40, 42 and 44 return to their
closed states. When only solenoid valve 22 fails or otherwise
toggles to its de-energized state, pressure switches 42 and 44
sense a decrease in pressure and open their contacts. Upon reset of
solenoid valve 22, the contacts of pressure switches 42 and 44
return to their closed states. When only solenoid valve 24 fails or
is otherwise de-energized, pressure switch 44 registers a reduction
in pressure to open the contacts thereof. Upon reset of solenoid
valve 24, the contacts of pressure switch 44 return to a closed
state. This operation of pressure switches 40, 42 and 44 is shown
in the truth table of FIG. 2.
[0030] The contacts of pressure switches 40, 42 and 44 may be
connected to suitable circuitry such as, for example, a
programmable logic controller (PLC) which may be programmed using
the truth table of FIG. 2 in a manner familiar to those skilled in
the art, to verify operation of each individual solenoid valve 20,
22 and 24 during testing thereof. The present invention thus
advantageously enables each solenoid valve to be tested
independently without disrupting fluid flow to valve 14. In this
manner, the solenoid arrangement 10 may be tested frequently
without disrupting plant process operation for increased safety
relative to prior art configurations. In addition, safety is
enhanced by effecting a cessation of fluid flow to valve 14 upon
de-energization of less than a full complement of the solenoid
valves 20, 22 and 24, i.e., air flow is abated once any two of the
three valves changes state. This effectively permits solenoid
arrangement 10 to safely stop air flow even in the event one of the
valves 20, 22 and 24 fails in its energized state and becomes
non-operational. Such safety is achieved while advantageously
providing the low spurious trip rate typically associated with
conventional 2 out of 2 voting solenoid arrangements by requiring
two solenoids to change state before terminating fluid flow.
[0031] As also shown in FIG. 1 a stack selector valve including
valves 50 and 52 may be used to bypass the solenoid arrangement 10
for maintenance and/or replacement thereof. As shown, valve 50 is
disposed between fluid supply 12 and conduit 16 to selectively
divert fluid flow from conduit 16 to a pressure switch 54. Valve 52
is connected to fluid or air supply 12 upstream of valve 50, and is
coupled to both conduit 18 and to valve 14 for selectively coupling
air supply 12 directly to valve 14 while bypassing voting solenoid
arrangement 10. Where used herein "upstream" and "downstream" refer
to the fluid flow direction relative to components of the present
invention. For example, the term "upstream", when referring to a
component, refers to a direction counter to the direction of fluid
flow into or through the component, while "downstream" refers to
the direction of fluid flow through the component. Valves 50 and 52
of the stack selector valve are operable in tandem with one another
between a normal position in which air flows from supply 12,
through valve 50 to conduit 16, and from conduit 18 through valve
52 to valve 14 as shown, and a bypass position as shown in phantom.
In the bypass position, air flow bypasses solenoid arrangement 10
and also supplies pressure to pressure switch 54, which serves to
change the state of (i.e. open) the contacts thereof. Pressure
switch 54 is preferably connected to monitoring and/or control
circuitry such as the PLC discussed hereinabove to facilitate
monitoring the position of valves 50 and 52.
[0032] As shown and described herein, solenoid valves 20, 22 and 24
are preferably disposed in their energized states during normal
fluid flow through passageway 26 thereof to valve 14. This
generally provides increased safety, since any interruption in
power to the solenoid valves will tend to generate a change in
state of the valves to stop fluid flow to valve 14. However, these
solenoid valves may be disposed in their de-energized state during
normal fluid flow therethrough, without departing from the spirit
and scope of the present invention. Similarly, although the
contacts of pressure switches 42 and 44 are preferably disposed in
their open states and pressure switch 40 in the closed state when
solenoid valves 20, 22 and 24 are de-energized, any, or all of
these contacts may be disposed in their closed or open states when
the valves are de-energized, without departing from the spirit and
scope of the present invention.
[0033] As also shown, in a preferred embodiment, ports 203 and 205
of valve 20, port 223 of valve 22, and port 243 of valve 24 are
vented. However, these ports may be coupled to a fluid recovery
system, such as in the event fluid other than air, (i.e. hydraulic
fluid), is used, without departing from the spirit and scope of the
invention.
[0034] Referring now to FIGS. 3 and 4 an alternate embodiment of
the present invention is shown as voting solenoid arrangement 10'.
It is in many respects substantially similar or identical to
solenoid arrangement 10. As shown, solenoid arrangement 10'
includes solenoid valves 20 and 22 including pressure switches 40
and 42 disposed substantially as shown and described hereinabove
with respect to solenoid arrangement 10. Solenoid valve 24' is
substantially identical to solenoid valve 24 of FIG. 1, however as
shown, valve 24' is disposed in a reverse configuration relative to
valve 24. In this embodiment, conduits 30 and 34 are respectively
coupled to ports 244 and 242. Similarly, pressure switch 44 and
conduit 18 are respectively coupled to ports 243 and 241. In
addition, rather than one of the ports (i.e. port 243 of valve 24)
being vented, port 245 is plugged to prevent discharge of fluid
during normal fluid flow. In this embodiment, the contacts of
pressure switch 44 remain in a first state (i.e. closed) as long as
solenoid valve 24' is disposed in its energized state as shown.
Pressure switch 44 changes state only when solenoid valve 24' is
de-energized while solenoid valves 20 and 22 remain energized. In
such an event, fluid flowing through conduit 34 will be coupled to
the pressure switch 44 to thereby change or open its contacts. A
truth table showing the state of pressure switches 40, 42 and 44
during individual de-energization of solenoid valves 20, 22 and 24'
is shown in FIG. 4. Stack selector valve including valves 50 and
52, is disposed and operated substantially as described hereinabove
with respect to solenoid arrangement 10. In addition as shown, an
optional pressure switch 56 may be coupled between valve 52 and
valve 14 to monitor and verify flow of fluid therebetween.
[0035] The voting solenoid arrangements 10 and 10' of the present
invention including the stack selector valve formed by valves 50,
52 and pressure switch 54, may be implemented in any convenient
manner. For example the components thereof may be coupled to one
another as shown and described herein, using suitable conduit or
channel means such as tubing fabricated from a flexible polymeric
material, or from a metallic, material such as steel, copper, etc.
In a preferred embodiment, the solenoid valves of the present
invention are disposed within a unitary manifold (not shown), which
incorporates the fluid flow paths therein. The stack selector valve
including valves 50 and 52 may also be disposed within the manifold
if desired. Use of such a manifold, with the fluid pathways or
conduits integrally disposed therein, advantageously serves to
reduce installation and maintenance cost relative to the
non-manifolded arrangements.
[0036] Referring now to FIG. 5, another alternate embodiment of the
present invention is shown as voting solenoid arrangement 10". It
is in many respects substantially similar or identical to solenoid
arrangement 10. As shown, solenoid arrangement 10" includes
solenoid valves 20, 22 and 24 and including pressure switches 40,
42 and 44 disposed substantially as shown and described hereinabove
with respect to solenoid arrangement 10. Solenoid arrangement 10"
further includes a bidirectional five-port valve 55 in place of
stack selector valves 50 and 52 (which are used in solenoid
arrangement 10 and shown in FIG. 1). Valve 55 is typically included
inside the manifold and functions similarly to valves 20, 22, 24
except that it is generally preferred that it be manually operable.
In this embodiment, conduits 16 and 18 are coupled to ports 264 and
262, respectively. Port 263 is coupled through conduit 38 to port
244 of solenoid valve 24. In addition, port 261 is coupled to
supply 12, while port 265 is vented. Further, pressure switch 54"
is coupled to conduit 16. In the energized state valve 55 connects
supply 12 to conduit 16 and port 244 of solenoid valve 24 through
conduit 38 to conduit 18. In the de-energized state valve 55
connects supply 12 directly to conduit 18 and vents conduit 16,
which opens pressure switch 54". The artisan of ordinary skill will
recognize that solenoid arrangement 10" functions substantially
identically to that of solenoid arrangement 10. This is further
demonstrated by the truth table showing the state of pressure
switches 40, 42 and 44 during individual de-energization of
solenoid valves 20, 22, and 24 for solenoid arrangement 10", which
is identical to that of solenoid arrangement 10 (shown in FIG.
2).
[0037] The foregoing description is intended primarily for purposes
of illustration. Although the invention has been shown and
described with respect to an exemplary embodiment thereof, it
should be understood by those skilled in the art that the foregoing
and various other changes, omissions, and additions in the form and
detail thereof may be made therein without departing from the
spirit and scope of the invention.
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