Abstract:
A water and/or air dispenser for snowmaking system includes water and/or air supplying ducts and is equipped with at least one valve ( 9 ) associated with an electric actuator ( 10 ), the actuator ( 10 ) being connected to an electric power source ( 12, 19 ) and associated with its own management unit ( 11 ) to ensure the operation of the valve ( 9 ) between the open and closed configurations thereof. The dispenser is associated with security elements able to cause the valve ( 9 ) to be positioned in a known security configuration, for example tightly closed, in case of voltage cut-off at the electric source ( 12, 19 ), the security elements being integrated and including a capacitor-type electric unit ( 16 ), connected to the electric power source and to the actuator ( 10 ), the capacitor unit being able to store, and then return, a quantity of energy necessary for complete actuation of the valve, to implement the security elements.

Description:
The present invention belongs to the general field of artificial snow production. More particularly, it relates to a secured water and/or air dispenser for snowmaking system, equipped with a valve driven by an electric actuator; it also relates to the secured snowmaking equipment comprising such dispensers. 
     BACKGROUND OF THE INVENTION 
     Today&#39;s snowmaking equipments generally comprise several dozens of snowmakers distributed along the slope to be equipped and each supplied with water and possibly with air through branches of main ducts running along the slope (see notably documents KR-2002 000 6111 or U.S. Pat. No. 5,031,832). 
     At each snowmaker, these branches end at a water and/or air dispensing system which is equipped with means for managing the desired water and/or air flow rates of the snowmaker in question, these means generally consisting in a valve associated with a double-acting electric actuator supplied with a control voltage of typically 230 VAC. 
     These devices, as well as the management means thereof, are accommodated in a shelter located in close proximity of the snowmaker. For operation, they are supplied from the electricity network, typically 230 VAC. 
     For such equipments, it is important that the valve supplying the snowmaker can be placed in security configuration in case of electricity network failure. Indeed, in case of current cut-off during the snowmaker operation, in absence of such a security, the valve would stay in a defined configuration, with no more control possibility. 
     To that end, the snowmaking equipment conventionally comprises a back-up power supply, mounted in parallel with the main power supply, comprising a battery associated with a centralized inverter enabling, from an absence of current detected on the main power supply, to place all the valves of the slope snowmakers in a definite security configuration (fully and tightly closed state, or else). 
     However, these centralized security means need regular maintenance (in particular, for controlling the battery charge) and the overall production cost thereof is relatively high. 
     Further, an electric problem at one of the snowmakers may entail consequences on the operation of the whole equipment; for example, a short-circuit in a 230 VAC-powered motor will activate the differential security protection of the whole trail or slope. 
     SUMMARY OF THE INVENTION 
     In this framework, the object of the present invention is to remedy the above-mentioned shortcomings through a novel security system implementing simple, efficient and cheap means. 
     So, according to the present invention, the corresponding security means are integrated into the own management means of each dispenser and they comprise a capacitor-type electric unit connected to the electric power source and to the actuator, said capacitor unit being able to store, and then return, a quantity of energy necessary for complete actuation of the valve, this energy returning being used, during a voltage cut-off at the power source, to implement said security means. 
     According to a preferred embodiment, the management means of the valve actuator comprise a charger module located upstream from the capacitor unit, and on the other hand, a voltage up-converter unit located downstream from said capacitor unit, to recreate a supply voltage adapted to said valve actuator from the voltage generated by said capacitor unit. 
     On the other hand, the management means advantageously also comprise a control logic arranged to drive said actuator, said control logic being power-supplied from the voltage up-converter unit and associated with means for detecting the voltage cut-off at the electric source in order, when a power outage is detected, to drive said actuator so as to position the associated valve in the aimed security configuration. 
     In the framework of this preferred embodiment, the electric source supplies direct current to the charger module, the voltage up-converter unit also supplying direct current to feed an electric actuator powered with direct current or, in association with an inverter stage, with alternating current. 
     For example, a control voltage of 24 VDC intended for supplying the valve actuator as well as a control voltage of 5 VDC intended for supplying the control logic will be generated. Of course, other voltages are possible, including of electricity network (typically 230 VAC). 
     The means for detecting a voltage cut-off at the electric power source advantageously consist in a threshold relay interposed between the control logic and said electric source, upstream from the charger module. 
     According to another feature, the actuator is connected to the electric power source only through the charger module, the capacitor unit and the voltage up-converter unit, so as to ensure continuously the good operation of the security means. 
     Advantageously, the capacitor unit has a value between 20 and 1000 farads; more preferably, this value is between 100 and 300 farads. 
     Still according another feature, the dispenser management means comprise means for remotely reporting the voltage absence, as well as possibly means for transmitting certain state or measurement parameters related to the equipped valve, or the environment thereof, during the phase of absence of current. 
     The invention also relates to the operating method of the above-described dispenser, said method consisting in:
         charging and keeping charged the capacitor unit when the management means are powered from the electric power source,   detecting the voltage cut-off of the electric source, and   driving the actuator of the valve so as to cause the latter to be placed in the secured configuration, using the energy stored and returned by said capacitor unit.       

     The invention also relates to a snowmaking equipment equipped with a plurality of snowmakers each comprising a secured dispenser such as above-described, in which a control logic drives the electric actuator and is connected to a network management system, of the computer or programmable logic controller type, through a communication line. This communication line comprises at least one signal amplifying device connected to an electric power source, said signal amplifier comprising a secured supplying device including a charger module, a capacitor unit and a voltage up-converter unit, said capacitor unit being able to store a quantity of energy necessary for information to be transmitted on the communication line during a period long enough for the network management system to ensure that all the dispensers are placed in security condition, and then return thereof, this energy returning being used, during a voltage cut-off at the electric power source, to supply the signal amplifying device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be further illustrated, without being in any way limited, by the following description associated with the attached drawings, in which: 
         FIG. 1  schematically illustrates an equipment for artificial snowmaking comprising a plurality of snowmakers each associated with a water and air dispenser equipped with a valve driven thanks to an electric actuator; 
         FIG. 2  is a general synoptic diagram illustrating the main functionalities of a dispenser according to the invention associated with each snowmaker; 
         FIG. 3  is a general synoptic diagram of an embodiment variant of the dispenser of  FIG. 2 ; 
         FIG. 4  is a bloc diagram of a control board of the valve actuator, according to the synoptic diagram of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The snowmaking equipment illustrated in  FIG. 1  comprises a plurality of snowmakers  1  arranged to make artificial snow from pressurized water and air. 
     To that end, the equipment comprises an air source  2  and a water source  3  which supply each snowmaker  1  through main ducts, respectively  4  and  5 , and branches  6 ,  7 . The water and air ducts end, in each snowmaker  1 , at a dispenser  8  which is equipped with a valve  9  associated with an electric actuator  10  arranged to manage the water and air flow rates. This management is done individually at each snowmaker  1 . 
     In operation, each dispenser  8  is driven by management means  11  and power-supplied from a source  12 . These management means  11  are connected to a network management system  13 , of the computer or programmable logic controller type, through a communication line  14 . 
     According to the present invention, each dispenser  8  includes its own security means arranged to place the associated valve  9  in a given so-called “security” configuration, in case of outage of power supply  12 . For example, this security configuration may consist in a tightly closed configuration of valve  9 , stopping the water and air supply of the snowmaker. 
     These particular means appear in the synoptic diagram of  FIG. 2 , showing the main functional elements of management means  11  of actuator  10 . 
     As illustrated in  FIG. 2 , actuator  10  is driven by a micro-controller-type control logic  15  and is power-supplied from power supply  12 , through a capacitor unit  16  which is associated upstream to a charger module  17  and downstream to a voltage up-converter unit  18 . 
     Each actuator  10  is advantageously of the double-acting type and is powered with direct current. From a general power supply  12  supplying a voltage of 230 VAC, a power supply  19  arranged at each shelter of snowmaker  1  provides the required direct current supply. 
     For example, for an actuator  10  of the 24 VDC-powered reversible stepping motor type, power supply  19  supplies 24 VDC, charger module  17  is of the 24 VDC/5 VDC type, and voltage up-converter unit  18  is of the 5 VDC/24 VDC type. 
     Capacitor unit  16  needs to be adapted for storing a quantity of energy necessary for complete actuation of valve  9  by actuator  10 . According to the characteristics of valve  9  and actuator  10  thereof, this capacitor unit  16  will have a preferential value between 100 and 300 farads; in particular, for a slide-type valve  9  and a 12-watts DC power electric geared motor-type actuator  10 , two modules mounted in series can be used, each having a value of 350 farads (for example, ref. Maxwell BCAP 350F), to obtain a total value of 175 farads. These capacitor values enable, in case of outage of power supply  12 ,  19 , to ensure the operation of actuator  10  during a period long enough for the slide of valve  9  to be displaced, over a complete back or forward stroke, at least, so as to place this valve in the selected security configuration (the corresponding operation duration is relatively long, of the order of 1 to  6  minutes, because of the use of an electric geared motor). 
     Still in  FIG. 2 , it can be noticed that micro-controller  15  is supplied from voltage up-converter unit  18  via a 24 VDC/5 VDC-type converter system  20 . 
     On the other hand, this micro-controller  15  is associated with means  21  that enable an outage of power supply  12 ,  19  to be detected; these means herein consist in a threshold relay  21  interposed between power supply  19  and micro-controller  15  (upstream from charger module  17 ). 
     Consequently, in a “normal” operation, actuator  10  is supplied with electric current via the charger/capacitor/up-converter unit  17 ,  16 ,  18 , after the energy is stored and returned by the capacitor unit  16 . Presence of this charger  17 /capacitor  16 /up-converter  18  unit is virtually transparent. 
     In case of outage of power supply  12 ,  19 , the energy stored in capacitor unit  16  enables operation of micro-controller  15  to be continued and actuator  10  to be actuated. 
     Micro-controller  15  is informed of the supply outage by threshold relay  21  and it drives actuator  10  to reach the aimed security configuration of valve  9 . 
     As above-stated, the features of capacitor unit  16  are adapted for returning a sufficient energy with regard to this functionality, according to the operation characteristics of valve  9  and associated actuator  10 . 
     All dispensers  8  of the snowmaking equipment operate similarly and it is to be understood, then, that a supply voltage failure causes the whole equipment to be placed in security condition. 
     Further to this placement in security condition of valve  9 , management means  11  of each dispenser  8  can be programmed and structured for:
         remotely reporting the detected absence of voltage (for example, a specific alarm code will possibly be sent by micro-controller  15  to network management system  13 , through communication line  14 ),   transmitting, still remotely, in particular to network management system  13 , certain state or measurement parameters related to associated valve  9  (or the environment thereof) during the phase of absence of voltage (for example: placement in security position done, valve-slide stroke percentage done, fluid local pressure, flow rate, ambient temperature or fluid temperature . . . ).       

     Following an outage of power supply  12 ,  19 , micro-controller  15  continues to operate as long as it is sufficiently supplied from converter module  20  (itself supplied from up-converter unit  18 ). 
     Once capacitor unit  16  is fully discharged, valve  9  is immobilized by double-acting actuator  10  which is not any more supplied. Network management system  13  knows, thanks to the message sent, if valve  9  is in security position or not. If this valve  9  is in security position, a simple supply outage alarm is emitted; when power supply is restored, micro-controller  15  begins a sequence of snowmaker restarting, possibly under control of network management system  13 . If valve  9  is not in security position, a fault is generated by network management system  13  and an intervention demand will possibly be automatically launched, notably by phone calling. 
     In “normal” operation, as actuator  10  is connected to power supply  12 ,  19  through the charger  17 /capacitor  16 /voltage up-converter  18  unit, an operation fault of either of these elements leads to an absence of supply of associated actuator  10 . This dysfunctioning will be directly detected by micro-controller  15 , and/or by the absence of communication between valve  9  and network management system  13 , and/or by absence of information provided by the sensors of the valve, which enable the good operation of corresponding security means to be continuously ensured. 
     It is to be noticed that, if actuator  10  is powered with alternative current, it is enough to add an inverter stage to voltage up-converter unit  18  to convert the supplied direct current into alternative current. 
     As shown in the schematic synoptic diagram of  FIG. 3 , in an embodiment variant, the security unit (charger  17 /capacitor  16 /voltage up-converter  18 ) can be arranged in parallel with a direct supply of actuator  10  from power supply  19 . 
       FIG. 4  shows a bloc diagram of a control electronic board able to manage the operation of a dispenser  8  according to the invention, and in particular according to the synoptic diagram of  FIG. 2 . 
     This board  22  includes micro-controller  15 , capacitor charger  17  connected to supply connector  23  and capacitor unit  16 , voltage up-converter  18  connected to said capacitor unit  16  and to a power stage  24 , the latter being connected to connector  25  of actuator  10 . 
     Micro-controller  15  is power-supplied from voltage up-converter unit  18  through converter  20 . 
     Threshold relay  21  is interposed between supply connector  23  and micro-controller  15  (in an embodiment variant, means for detecting absence of voltage can be implemented by a suitable software function of the micro-controller). 
     On the other hand, micro-controller  15  is herein connected to: 
     
         
         
           
             TOR inputs  26 , for acquiring state information about certain parts (for example, stroke ends of the valve slide) 
             TOR outputs  27 , intended for the driving of various accessory parts by micro-controller (for example, secondary valves) 
             analog inputs  28 , for acquiring values of the physical magnitude transmitters (pressure, flow rate, temperature . . .) 
             communication ports  29  for dialogue between micro-controller  15  and network management system  13 ; and also for communication between the micro-controller and the different measuring parts necessary for the driving of valve  9  or snowmaker  1 . 
           
         
       
    
     Of course, the final electric diagram will take into account conventional electric and electronic protections and adaptations. 
     On the other hand, given the long distances to be equipped (sometimes several dozens of kilometres) and due to the need for remotely controlling dispensers  8 , an amplification of communication signals can prove necessary, at regular intervals or not. This amplifying function is entrusted to electronic boards called “repeaters”, denoted  30  in  FIG. 1 . These boards are supplied from main voltage  12  (230 VAC). For optimization and securing of the equipment, these repeaters  30  are advantageously equipped with a secured power supply device similar to that above-described for dispensers  8 . 
     This device will comprise a 5 VDC-power supply, associated with a charger/capacitor(s)/voltage up-converter security unit (mounted in series or in parallel with the conventional power supply). The characteristics of the components used (in particular, values of the capacities) will be adapted to enable repeaters  30  so equipped to continue being supplied a few minutes following the outage of the main power supply  12 . Given the absence of mechanical parts to be operated, the values of the capacitor(s) used will possibly be noticeably lesser relative to those above-mentioned for dispenser  8 . 
     Generally, it will be noticed that the present invention applies not only to the dispenser of the snowmaker, but also to any other dispenser placed on the snowmaking network, for example a dispenser for controlling the distribution of the water flow rates in the snowmaking network. In particular, in great networks, it can be useful to arrange such a device to restrict the drainage flow rate in some areas so as to optimize the water returning into the tank. 
     In this case, a drainage strategy for emergency situations will be materialized by a sequence in network management system  13  (then, the security configuration of the valve will possibly correspond to an open position at a certain set value). 
     In any case, structure of the means according to the invention is adapted according to the types of valve  9  and actuator  10  that are present. It also can be contemplated to secure, through means according to the invention, a mere air valve necessary at a place or another of the snowmaking equipment. 
     For example, valves  9  can be of the single-fluid or double-fluid type and of the slide, spherical plug, butterfly, seat style or the like. Actuators  10  can be of the brushless geared motor type or of the stepping geared motor type. 
     On the other hand, as above-stated, any security configuration will be possible, according in particular to the valve type, for example tightly closed, or else partially open or totally open.