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EP 1 266 143 B1 |
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EUROPEAN PATENT SPECIFICATION |
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Mention of the grant of the patent: |
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24.08.2005 Bulletin 2005/34 |
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Date of filing: 20.03.2001 |
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International Patent Classification (IPC)7: F15B 13/043 |
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International application number: |
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PCT/US2001/008869 |
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International publication number: |
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WO 2001/071198 (27.09.2001 Gazette 2001/39) |
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WIRELESS, INTRINSICALLY SAFE VALVE
KABELLOSES, EIGENSICHERES VENTIL
ROBINET SANS FIL, A SECURITE INTRINSEQUE
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Designated Contracting States: |
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DE ES FR GB IT |
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Priority: |
21.03.2000 US 191066 P
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Date of publication of application: |
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18.12.2002 Bulletin 2002/51 |
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Proprietor: ROSS OPERATING VALVE COMPANY |
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Michigan 48084-4838 (US) |
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Inventor: |
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- SCHNELL, Richard, E.
Oswego, IL 60543 (US)
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Representative: Neumann, Ernst Dieter et al |
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Harwardt Neumann Patent- und Rechtsanwälte,
Brandstrasse 10 53721 Siegburg 53721 Siegburg (DE) |
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References cited: :
US-A- 3 954 046 US-A- 4 443 853 US-A- 5 570 716 US-A- 5 709 245
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US-A- 4 412 355 US-A- 5 543 627 US-A- 5 706 852
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Note: Within nine months from the publication of the mention of the grant of the European
patent, any person may give notice to the European Patent Office of opposition to
the European patent
granted. Notice of opposition shall be filed in a written reasoned statement. It shall
not be deemed to
have been filed until the opposition fee has been paid. (Art. 99(1) European Patent
Convention).
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BACKGROUND
[0001] The present invention relates generally to intrinsically safe valves and, more particularly,
to valves that employ a piezo-electric element that operates using minimal electrical
energy.
[0002] Many industries utilize and/or manufacture flammable chemicals. These industries
must take particular caution to prevent ignition of such chemicals in order to prevent
fires or explosions. Chemical management systems require significant consideration
towards minimizing the potential for igniting such chemicals. Chemical management
systems typically are designed so that arcing and sparks which often result from connecting
and disconnecting electrical circuits is minimized. Presently, such chemical management
systems utilize expensive wiring and switch elements in order to achieve this goal.
[0003] One particular example of such a chemical management system utilizes solenoid valves
in order to displace a valve element to control the flow of flammable chemicals. An
example of prior Art can be found in US 5 706 852. Present systems utilize expensive
low spark implementations. These implementations include sparkless wiring and sparkless
switches which are expensive because of the significant shielding of the wiring and
sealing of the switches. Even though these switches typically operate at a signal
voltage level rather than a higher, working voltage levels, minimal sparks in a highly
flammable environment can present extremely hazardous situations.
[0004] Thus, there is a need for providing an intrinsically safe valve which reduces the
overall cost of valves in a chemical management system.
SUMMARY OF THE INVENTION
[0005] In accordance with the teachings of the present invention, a valve system is disclosed
that employs a low voltage element, such as a piezo-electric element, to activate
a fluid flow valve so as to use a minimal amount of electrical energy. The piezo-electric
element activates a pilot pressure valve, which allows a control fluid to pass to
a main control valve. The control fluid causes the main control valve to activate
a pneumatic rotary operator, which is turn operates the fluid flow valve. A switching
assembly is employed to activate the piezo-electric element. The switching assembly
can include various types of switching devices, such as RF switching devices, optical
switching devices, infrared switching devices and low voltage electrical switching
devices, to allow the valve to be controlled from a remote location.
[0006] For a more complete understanding of the invention, its objects and advantages, reference
should be made to the following specification and to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The drawings, which form an integral part of the specification, are to be read in
conjunction therewith, and like reference numerals are employed to designate identical
components in the various view.
Figure 1 is a schematic block diagram of an intrinsically safe valve that is activated
by an RF signal, according to an embodiment of the present invention;
Figure 2 is a schematic block diagram of an intrinsically safe valve that is activated
by an optical signal, according to another embodiment of the present invention;
Figure 3 is a schematic block diagram of a switching system for a valve assembly that
employs an optical switch device, according to another embodiment of the present invention;
Figure 4 is a schematic block diagram of a switching system for a valve assembly that
employs an optical switch device, according to another embodiment of the present invention;
Figure 5 is a schematic block diagram of a switching system for a valve assembly that
employs an optical switch device, according to another embodiment of the present invention;
Figure 6 is a schematic block diagram of a switching system for a valve assembly that
employs an opto-coupler switch device, according to another embodiment of the present
invention; and
Figure 7 is a schematic block diagram of a switching system for a valve assembly that
employs an infrared switch device, according to another embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0008] Figure 1 is a plan view of an intrinsically safe valve system 10 according to the
invention. The valve system 10 includes a valve activation assembly 12, a transmitter
14, a working element 16 and a fluid valve 18. The transmitter 14 transmits a signal
24 from an antenna 26 that is received by an antenna 30 associated with the valve
assembly 12. In this embodiment, the signal 24 is an RF signal, but as will be discussed
in more detail below, other signals can be used, such as optical signals, infrared
signals, and low voltage signals. The signal 24 may be encoded by the transmitter
14 so that only a particular valve assembly 12 operates in response to the signal
24. Thus, the valve assembly 12 may be addressable to distinguish a particular valve
assembly 12 from other valve assemblies. When the valve assembly 12 receives the signal
24, it activates the working element 16, which opens or closes the fluid valve 18
depending on its normal state. The valve 18 controls the flow of chemicals between
a first side 20 and a second side 22. The valve 18 can be any type of actuator that
operates under low voltage. Particularly, the valve 18 can be any actuation device
that can benefit from the system described herein.
[0009] The receiver 28 includes a detector 30 that detects the signal 24 from the antenna
30. A battery 32 provides electrical energy to the receiver 28. The receiver 28 includes
a non-contacting switch 34 responsive to the signal 24 from the antenna 30. If the
transmitter 14 encodes the signal 24, the non-contacting switch 34 responds only if
the receiver 28 is the properly addressed receiver.
[0010] The receiver 28, through non-contacting switch 34, outputs an electrical signal to
a pilot valve 36. The pilot valve 36 includes a piezo-electric switch assembly 38
attached to a valve body 40 of the valve 36. The switch assembly 38 includes a piezo-electric
element whose structural configuration changes in response to a voltage, as is well
understood in the art . The piezo-electric element can be any piezo element suitable
for the purposes described herein. In alternate embodiments, the piezo-electric element
can be other types of low voltage elements suitable for the purposes described herein,
such as those that employ bending element technology, such as ceramic elements. The
valve 36 is a two position valve which supplies input air at a pilot pressure to a
pilot line 42. The assembly 38 includes a baffle (not shown) which deflects upon application
of a voltage. Deflection of the baffle opens a small orifice to allow air at the pilot
pressure to be applied to the pilot line 42, which is then applied to a main spool
or poppet valve 44. Preferably, the pilot valve 36 is embodied as a commercial available
valve.
[0011] The main valve 44 controls application of input air and exhaust to the working element
16. In particular, upon application of the pilot pressure from the pilot line 42,
the main valve 44 applies input air to displace the working element 16. The working
element 16 may be embodied as a pneumatic, rotary operator for the valve 18. Accordingly,
the valve 18 may be embodied as a butterfly valve so that displacement of the working
element 16 opens and closes the valve 18. Upon removal of the electrical signal output
by the receiver 28, the pilot valve 36 cuts off the supply of pilot pressure to the
pilot line 42. This in turn displaces the main valve 44 to a deactuated position,
which displaces the working element 16 to its initial position, thereby closing the
valve 18.
[0012] Figure 2 depicts an intrinsically safe valve system 50, according to another embodiment
of the present invention. The valve system 50 is arranged similarly to the valve system
10, and like reference numerals will be used to designate like elements. Such like
elements will not be described with respect to Figure 2 as they operate as described
with respect to Figure 1.
[0013] Of particular interest in the system 50 is the actuation technique for operating
the pilot valve 36. In particular, an optical actuation system 52 replaces the transmitter
14 and the receiver 28 of the system 10. The system 52 includes a fiber optic switch
54 that outputs an optical signal on a fiber optic cable 56. The fiber optic cable
56 applies the optical signal to a fiber optic detector 58. The fiber optic detector
58 converts the optical signal from the switch 54 to a voltage for operating the assembly
38 of the pilot valve 36. The fiber optic detector 58 outputs the electrical signal
on conductors 60.
[0014] The above-described embodiments offer several advantages. In conventional systems,
where an operating switch is located remotely from the actual valve, an electrical
conductor must be provided between the switch and the valve. Routing these electrical
conductors can be expensive in both time and materials, as intrinsically safe systems
require explosion-proof wiring. The subject invention, however, eliminates the need
for routing electrical conductors, because the transmitter 14 and the receiver 28
need only to electromagnetically communicate without being directly connected by electrical
conductors. Thus, the subject invention provides a significant cost savings.
[0015] Further, utilizing a piezo-electric element and the pilot valve 36 eliminates the
opportunity for arcing due to electrical switch connection and disconnection. Only
a minimal amount of electrical energy is needed to actuate the pilot valve 36, thus
providing an intrinsically safe valve system. Further yet, because the receiver 28
and the assembly 38 only require a minimal amount of energy, the battery 32 provides
substantial battery life for operating the valve system 10 over an extended period
of time. With respect to Figure 2, the battery 32 may be eliminated because the optical
signal provide sufficient voltage for operating the assembly 38.
[0016] Figure 3 is a schematic block diagram of a valve switching system 70 that can replace
certain switching devices of the valve systems 10 and 50, as will become apparent
from the discussion herein. Particularly, the valve switching system 70 can replace
the transmitter 14 and the receiver 28 in the system 10, and replace the optical switch
54 and the fiber optic detector 58 in the system 50. The pilot valve 36, the main
valve 44, the working element 16 and the fluid valve 18 would operate in the manner
discussed above. The system 70 includes a control board 72 that controls the piezo-electric
element within the assembly 38.
[0017] The valve 18 is open or closed, depending on its normal position, by an optical signal
from a light source 74. The light source 74 can be any selectively activated light
source suitable for the purposes described herein. The optical signal generated by
the light source 74 propagates down optical fibers 76 arranged in a fiber bundle 78.
Light emitted from the ends of the fibers 76 opposite the source 74 is received by
a plurality of solar cells 80 arranged in a cell bank 82. The solar cells 80 convert
the optical energy to an electrical signal that is provided on line 84. The electrical
signal on line 84 is amplified by a DC-DC converter circuit 86 to amplify the signal
level suitable for a particular application. In this embodiment, the DC-DC converter
circuit 86 amplifies the.signal level to 7.5 volts. The converter circuit 86 is shown
by way of a non-limiting example in that any amplifier circuit suitable for the purposes
described herein can be used. The amplified electrical signal on line 84 is then sent
to the control board 72 that activates the piezo-electric element to switch the pilot
valve 36 in the manner as discussed above. The solar cells 80, the converter circuit
86 and the control board 72 could be internal to the assembly 38.
[0018] Figure 4 is a schematic block diagram of a valve switching assembly 92 that is a
variation of the switching assembly 70 discussed above. The switching assembly 92
powers a control board 94 to control the piezo-electric element within the assembly
38. In this embodiment, a 1.2 volt signal is used to control the piezo-electric element.
The system 92 has particular application where a single light source powers many low
voltage valve assemblies, and a separate low power optical signal is used to independently
control each separate valve.
[0019] In this embodiment, a light source 96 provides an optical signal on a plurality of
optical fibers 98 and 100, where the optical fiber 98 powers the control board 94
and the fiber optical cable 100 powers another valve switching assembly (not shown).
The light source 76 can be any light source capable of providing optical signals to
a plurality of switching assemblies consistent with the discussion herein. The light
source 76 controls two separate valve switching assemblies in this embodiment, but
as will be appreciated by those skilled in the art, more optical fibers connected
to the light source 96 can be provided to control more valve switching assemblies.
The light source 96 is maintained on so optical power is continually available to
any of the several valve switching assemblies that may at any time require optical
power.
[0020] The optical signal on the fiber cable 98 that is emitted from an end of the cable
98 opposite the source 90 is received by a plurality of solar cells 104 arranged in
a solar cell bank 106. The solar cells 104 convert the light energy to electrical
energy available on line 108. A photodiode 110 is positioned in the electrical line
108, and conducts when it receives an optical signal. When the valve 18 is to be activated,
a fiber transmitter 112, such as an LED, is activated to provide an optical signal
on a fiber optical cable 114. The photodiode 110 receives the light from an end of
the cable 114 opposite the transmitter 112, and conducts so that the electrical signal
generated by the solar cells 104 activates the control board 94. The control board
94, in turn, activates the piezo-electric element in the assembly 38 to control the
pilot valve 36, as discussed above. The solar cells 104, the photodiode 110 and the
control board 94 can be internal to the assembly 38.
[0021] Figure 5 shows a schematic block diagram of another valve switching system 120 for
activating the valve 18 in the manner discussed herein. The system 120 includes a
control board 122 that operates with a 1.2 volt signal to activate the piezo-electric
element in the assembly 38. The switching system 120 includes an optical transmitter
circuit 124 that includes a manual switch 126, a DC voltage source 128, for example
a 9 volt DC source, and a fiber transmitter 130, such as an LED. When the switch 126
is closed, the voltage provided by the source 128 causes the transmitter 130 to transmit
light down a fiber optic cable 132.
[0022] The system 120 further includes a switch assembly 136 including a DC voltage source
138, such as a 1.5 DC voltage source, and a photodiode 140. When the photodiode 140
receives light from an end of the optical cable 132 opposite the transmitter 130,
it conducts which causes the DC voltage from the source 138 to energize the control
board 122. As above, the control board 122 activates the piezo-electric element in
the assembly 38 which controls the pilot valve 36. The switch assembly 136 and the
control board 122 can be internal to the assembly 38.
[0023] In accordance with another low voltage application, Figure 6 shows a schematic block
diagram of a valve switching system 144 having a control board 146 that is the same
as the control board 122, and a switch assembly 148 similar to the switch assembly
136. The switch assembly 148 includes a DC voltage source 150 and an opto-coupler
152 that replaces the photodiode 140. The opto-coupler 152 receives a low voltage
signal from a suitable voltage source 154 that causes the opto-coupler 152 to conduct
and energize the control board 146.
[0024] Figure 7 is a schematic block diagram of a valve switching system 158 that includes
a control board 160 that is the same as the control boards 122 and 146 above, and
a switch assembly 162 that is similar to the switch assemblies 136 and 148. The switch
assembly 162 includes a DC voltage source 164, a capacitor 166 and an infrared source
168. A low voltage signal is applied to the infrared source 168 that causes the capacitor
166 to conduct which energizes the control board 160.
[0025] While the invention has been described in its presently preferred form, it is to
be understood that there are numerous applications and implementations for the present
invention. Accordingly, the invention is capable of modification and changes without
departing from the spirit of the invention as set forth in the appended claims.
1. Valve system in a chemical management system for controlling flow of a volatile chemical,
comprising:
a remote transmitter (14), said transmitter generating a valve activation signal (24);
a receiver (28), said receiver generating a piezo-electric element signal in response
to the activation signal;
an assembly including a piezo element (38), said assembly generating a pilot signal
in response to the piezo element signal;
a pilot valve (36), said pilot valve passing a pilot air pressure in response to the
pilot signal;
a main valve (44), said main valve generating a working air pressure in response to
the pilot air pressure;
a pneumatic rotary operator (16) responsive to the working air pressure; and
a fluid flow valve (18) for controlling the flow of the volatile chemical from a first
side (20) to a second side (22), said fluid flow valve being displaced by the pneumatic
rotary operator.
2. System according to claim 1, characterized in that the receiver (28) is part of a switch circuit (92) that further includes a photodiode
(110) and the remote transmitter is an optical transmitter (112), said photodiode
being positioned on an electrical line (108) between at least one solar cell (104)
and the piezo element (38), said photodiode being responsive to an optical signal
acting as the valve activation signal from the optical transmitter, said photodiode
conducting in response to the optical signal to allow the photodiode signal to energize
the piezo element (38).
3. System according to claim 1, characterized in that the transmitter is an RF transmitter (14), the valve activation signal is an RF signal
(24) and the receiver is an RF receiver (28).
4. System according to claim 1, characterized in that the remote transmitter includes an optical transmitter (130), a DC voltage source
(128), and a manual switch (126), said manual switch being activated to cause the
DC voltage source to energize the optical transmitter and generate the valve activation
signal.
5. System according to claim 1, characterized in that the transmitter is an optical transmitter (112), the activation signal is an optical
signal, and the receiver is and optical detector (110).
6. System according to claim 5 characterized in that the optical detector is selected from the group consisting of photodiodes (110) and
solar cells (104).
7. System according to claim 5 characterized in that the transmitter (112) is selected from the group consisting of infrared devices,
LED devices and light sources.
8. System according to claim 1, characterized in that the transmitter is an optical transmitter circuit that includes an optical device
(152) and a DC power source (150), said DC power source providing the valve activation
signal and said optical device passing the valve activation signal in response to
a transmitter signal.
9. System according to claim 8 characterized in that the optical device is a photodiode (110, 140) and the transmitter signal is an optical
signal.
10. System according to claim 8 characterized in that the optical device is an opto-coupler (152) and the switch signal is a low voltage
signal.
11. System according to claim 8 characterized in that the optical device is an infra-red device (168) and the switch signal is a low voltage
signal.
1. Ventilsystem in einem Steuerungssystem für Chemikalien zur Volumenstromregelung einer
flüchtigen Chemikalie, umfassend:
einen Fernübertrager (14), wobei der genannte Fernübertrager ein Ventilansteuerungssignal
(24) erzeugt;
einen Empfänger (28), wobei der genannte Empfänger ein Piezo-Element-Signal als Reaktion
auf das Ansteuerungssignal erzeugt;
eine Anordnung mit einem Piezo-Element (38), wobei die genannte Anordnung ein Steuersignal
als Reaktion auf das Piezo-Element-Signal erzeugt;
ein Schaltventil (36), wobei das genannte Schaltventil einen Steuerluftdruck als Reaktion
auf das Steuersignal durchläßt;
ein Hauptventil (44), wobei das genannte Hauptventil einen Arbeitsluftdruck als Reaktion
auf den Steuerluftdruck aufbaut;
eine pneumatische drehbare Stelleinheit (16), die auf den Arbeitsluftdruck anspricht;
und
ein Fluidströmungsventil (18) zur Steuerung der Volumenmenge der flüchtigen Chemikalie
von einer ersten Seite (20) zu einer zweiten Seite (22), wobei das genannte Fluidströmungsventil
durch die pneumatische drehbare Stelleinheit verstellt wird.
2. System nach Anspruch 1,
dadurch gekennzeichnet,
daß der Empfänger Teil eines Schaltkreises (92) ist, der ferner eine Photodiode (110)
umfaßt, und daß der Fernübertrager ein optischer Sender (112) ist, wobei die genannte
Photodiode in einer elektrischen Leitung (108) zwischen zumindest einer Solarzelle
(104) und dem Piezo-Element (38) eingesetzt ist, wobei die genannte Photodiode auf
ein vom optischen Sender kommendes optisches Signal reagiert, das als Ventilansteuerungssignal
wirkt, und wobei die genannte Photodiode als Reaktion auf das optische Signal leitfähig
wird, damit das Photodiodensignal das Piezo-Element (38) betätigen kann.
3. System nach Anspruch 1,
dadurch gekennzeichnet,
daß der Fernübertrager ein RF-Fernübertrager (14), das Ventilansteuerungssignal ein RF-Signal
(24) und der Empfänger ein RF-Empfänger (28) ist.
4. System nach Anspruch 1,
dadurch gekennzeichnet,
daß der Fernübertrager einen optischen Sender (130), eine Gleichspannungsquelle (128)
sowie einen handbetätigten Schalter (126) umfaßt, wobei der genannte handbetätigte
Schalter aktiviert wird, damit die Gleichspannungsquelle den optischen Sender unter
Spannung setzt und das Ventilansteuerungssignal erzeugt wird.
5. System nach Anspruch 1,
dadurch gekennzeichnet,
daß der Fernübertrager ein optischer Sender (112), das Ansteuerungssignal ein optisches
Signal und der Empfänger ein optischer Detektor (110) ist.
6. System nach Anspruch 5,
dadurch gekennzeichnet,
daß der optische Detektor aus einer Gruppe, bestehend aus Photodioden (110) und Solarzellen
(104), ausgewählt ist.
7. System nach Anspruch 5,
dadurch gekennzeichnet,
daß der Sender (112) aus einer Gruppe, bestehend aus Infrarot-Vorrichtungen, LED-Vorrichtungen
und Lichtquellen, ausgewählt ist.
8. System nach Anspruch 1,
dadurch gekennzeichnet,
daß der Fernübertrager eine optische Senderschaltung ist, die eine optische Vorrichtung
(152) und eine Gleichstromquelle (150) umfaßt, wobei die genannte Gleichstromquelle
das Ventilansteuerungssignal bereitstellt und die genannte optische Vorrichtung das
Ventilansteuerungssignal als Reaktion auf ein Sendersignal weiterleitet.
9. System nach Anspruch 8,
dadurch gekennzeichnet,
daß die optische Vorrichtung eine Photodiode (110, 140) und das Sendersignal ein optisches
Signal ist.
10. System nach Anspruch 8,
dadurch gekennzeichnet,
daß die optische Vorrichtung ein Optokoppler (152) und das Schaltersignal ein Niedrigvoltsignal
ist.
11. System nach Anspruch 8,
dadurch gekennzeichnet,
daß die optische Vorrichtung eine Infrarotvorrichtung (168) und das Schaltersignal ein
Niedrigvoltsignal ist.
1. Système de soupape dans un système de gestion de produits chimiques pour contrôler
l'écoulement d'un produit chimique volatile, comportant
un transmetteur à distance (14), ledit transmetteur générant un signal d'activation
de soupape (24);
un récepteur (28), ledit récepteur générant un signal d'élément piézoélectrique
en réponse au signal d'activation ;
un assemblage comprenant un élément piézoélectrique (38), ledit assemblage générant
un signal pilote en réponse au signal d'élément piézoélectrique ;
une soupape pilote (36), ladite soupape pilote laissant passer une pression d'air
pilote en réponse au signal pilote ;
une soupape principale (44), ladite soupape principale générant une pression d'air
de fonctionnement en réponse à la pression d'air pilote ;
un opérateur pivotant pneumatique (16) sensible à la pression d'air de fonctionnement
; et
une soupape d'écoulement de fluide (18) pour contrôler l'écoulement du produit
chimique volatile depuis un premier côté (20) vers un second côté (22), ladite soupape
d'écoulement de fluide étant déplacée par l'opérateur pivotant pneumatique.
2. Système selon la revendication 1, caractérisé en ce que le récepteur (28) est une partie d'un circuit de commutation (92) qui comprend en
outre une photodiode (110) et le transmetteur à distance est un transmetteur optique
(112), ladite photodiode étant positionnée sur une ligne électrique (108) entre au
moins une cellule solaire (104) et l'élément piézoélectrique (38), ladite photodiode
étant sensible à un signal optique agissant comme signal d'activation de soupape provenant
du transmetteur optique, ladite photodiode conduisant en réponse au signal optique
pour permettre au signal de photodiode d'activer l'élément piézoélectrique (38).
3. Système selon la revendication 1, caractérisé en ce que le transmetteur est un transmetteur RF (14), le signal d'activation de soupape est
un signal RF (24) et le récepteur est un récepteur RF (28).
4. Système selon la revendication 1, caractérisé en ce que le transmetteur à distance comprend un transmetteur optique (130), une source de
tension continue (128), et un commutateur manuel (126), ledit commutateur manuel étant
activé afin d'amener la source de tension continue à activer le transmetteur optique
et à générer le signal d'activation de soupape.
5. Système selon la revendication 1, caractérisé en ce que le transmetteur est un transmetteur optique (112), le signal d'activation est un
signal optique, et le récepteur est un détecteur optique (110).
6. Système selon la revendication 5, caractérisé en ce que le détecteur optique est sélectionné parmi le groupe constitué de photodiodes (110)
et de cellules solaires (104).
7. Système selon la revendication 5, caractérisé en ce que le transmetteur (112) est sélectionné parmi le groupe constitué de dispositifs infrarouges,
dispositifs LED et sources lumineuses.
8. Système selon la revendication 1, caractérisé en ce que le transmetteur est un circuit de transmetteur optique qui comprend un dispositif
optique (152) et une source d'alimentation continue (150), ladite source d'alimentation
continue délivrant le signal d'activation de soupape et ledit dispositif optique laissant
passer le signal d'activation de soupape en réponse à un signal de transmetteur.
9. Système selon la revendication 8, caractérisé en ce que le dispositif optique est une photodiode (110, 140) et le signal de transmetteur
est un signal optique.
10. Système selon la revendication 8, caractérisé en ce que le dispositif optique est un optocoupleur (152) et le signal de commutateur est un
signal à basse tension.
11. Système selon la revendication 8, caractérisé en ce que le dispositif optique est un dispositif infrarouge (168) et le signal de commutateur
est un signal à basse tension.