Abstract:
A fluid flow control device ( 1 ) comprising at least one valve, the or each valve being controlled by an electrically-operate e actuator ( 32 ), a control means ( 27 ) for controlling the actuators and a communication means ( 28 ) to provide signals for the control means ( 27 ), wherein the device ( 1 ) includes an electrical power generation means ( 5 ) to generate electricity from the flow of fluid in the control device to operate the actuators ( 32 ), the control means ( 27 ) and the communication means ( 28 ). The device does not require an external electricity supply as it generates its entire electricity requirement locally. The device ( 1 ) may also receive instructions wirelessly to control the at least one valve.

Description:
FIELD OF INVENTION 
   This invention relates to a fluid flow control device and more particularly to valve islands comprising valves for controlling fluid-powered devices such as, for example, actuating cylinders. The invention is applicable to pneumatic and hydraulic control valves but, for convenience, this specification refers largely to the former. 
   BACKGROUND OF INVENTION 
   It is now commonplace in, for example, production machinery for all of the actuating cylinders to be controlled by respective directional control valves that are usually mounted on one and the same ‘valve island’. The valves in the valve islands are usually controlled by solenoids that receive electrical signals to actuate the associated valve. The valve islands are thus connected to a pneumatic line that supplies pressurized gas, an electrical line to provide power for the solenoids and an electrical communication line to control the operation of the valve island. Such valve islands have the advantage of compactness but each one requires the connection of electrical, communication and pneumatic lines. Therefore, production machinery having several valve islands will require a relatively complex network of supply lines for their operation, which can be difficult to install and expensive for the end-user. 
   More recently valve islands have been constructed to make use of wireless communication technology to control the operation of the solenoids on the valve island. Thus, these valve islands do not require a communication line. However, these valve islands still require a network of pneumatic and electrical power lines and thus the support network for a plurality of valve islands is still complex. 
   SUMMARY OF INVENTION 
   According to the present invention, we provide a fluid flow control device comprising at least one valve, the or each valve being controlled by an electrically-operable actuator, a control means for controlling the actuators and a communication means to provide signals for the control means, wherein the device includes an electrical power generation means to generate electricity from the flow of fluid in the control device to operate the actuators, the control means and the communication means. 
   This device does not require an external electricity supply as it generates its entire electricity requirement locally. This is particularly advantageous if the device controls the flow of water, for example, as it does not require an external electricity supply, which may be hazardous in the vicinity of water. Preferably, the device receives fluid from a fluid flow supply line. 
   Preferably the communication means operates wirelessly. Therefore the only external supply line that the control device requires to operate is the fluid flow line. The fluid flow supply line may be a pneumatic line supplying pressurized gas or a hydraulic line supplying hydraulic fluid. This makes the control device easy to install, as only a single supply line is required. This arrangement is particularly advantageous as the complexity of the support supply network is significantly reduced. 
   The communication means may operate wirelessly using a radio frequency standard such as industrial Bluetooth standard or ZigBee. However the communication means may operate using Wi-Fi, infrared, optical or ultrasonic standards. 
   Preferably, the electrical power generation means uses the fluid flow from the fluid flow supply line to generate electricity. 
   Alternatively, the electrical power generation means uses the fluid flow from the exhaust of the or each valve to generate electricity. Thus, the control device uses fluid that would not normally be utilised and, in the case of a pneumatic system, exhausted to atmosphere. For a hydraulic system, the exhaust fluid would not normally be utilised and simply return to a hydraulic reservoir. This improves the efficiency of the control device. 
   Where the electrical power generation means generates electricity from the fluid flow from the exhaust of the valve or valves, the control device may include an initial power source that provides the power to operate the actuators, the control means and the communication means until the flow of fluid from the exhaust of the valve or valves is sufficient to cause the power generation means to generate electricity. The initial power source may be a pre-charged battery. Alternatively, it could be a vessel of compressed fluid that is adapted to be exhausted through the power generation means to generate electricity initially. The initial power source may be rechargeable. 
   Preferably, the device includes a selection valve that has two inputs and one output to the power generation means, the first input receives fluid flow from the fluid flow supply line and the second input receives fluid from the exhaust of the or each valve, the selection valve being adapted to select which of the inputs is in communication with the power generation means. 
   Preferably, the selection valve is actuated by a solenoid. Thus, the selection valve can be controlled electronically to select which fluid flow is used to generate electricity in the device. Preferably, the selection valve is biased so that by default the fluid flow supply line is in communication with the power generation means. 
   Preferably, the solenoid of the selection valve is supplied with power from the power generation means. Thus, once the solenoid is supplied with the required power, it actuates the selection valve that switches so that the exhaust fluid flow is directed to the power generation means. This is advantageous as the selection valve does not require sophisticated control means, and the device utilises the exhaust fluid flow as soon as the flow from the fluid flow supply line has generated sufficient power to operate the actuators, control means, the communication means and the selection valve solenoid. 
   Preferably, the power generation means comprises a turbine that is connected to an electrical generator. 
   Preferably, the power generation means is connected to an accumulator such that the accumulator stores the electrical power generated by the power generation means. The accumulator may be a capacitor or a rechargeable battery. 
   A rectifier may rectify the electrical output from the power generation means before it enters the accumulator. 

   
     DESCRIPTION OF THE DRAWINGS 
     There now follows by way of example only a detailed description of the present invention with reference to the accompanying drawings, in which: 
       FIG. 1  shows a perspective view of a valve island in accordance with the invention; and 
       FIG. 2  is a diagram illustrating the valve island shown in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a fluid flow control device in the form of a valve island  1 . The valve island  1  comprises a series of interconnected valve slices  2  between two end plates  3 ,  4 . Each valve slice  2  houses a valve (not shown) and an electrically-operable actuator (not shown) such as a solenoid. The valves in the valve slices  2  control fluid flow from a pneumatic supply line (not shown). In one of the end plates  3  there is mounted electrical power generation means  5  and an accumulator  6 . The power generation means  5  includes a turbine  7  of known design that operates using the fluid flow through the valve island  1 . The power generation means  5  is connected to the accumulator  6 , which stores the electrical energy generated. 
   A diagram of the valve island  1  is shown in  FIG. 2 , although only one valve slice  2  is shown. A pneumatic supply line  8 , which forms part of a supply network, provides the valve island  1  with an external supply of compressed air. The external supply line  8  branches when it enters the valve island  1  to form an input supply line  9  and a valve slice supply line  10 . The branch may be biased to ensure that the majority of the air is diverted to the valve slice supply line  10 , which is connected to each valve slice  2  in the valve island  1  via a manifold (not shown) that connects to an input port  11 . The input supply line  9  is connected to a selection valve  12 . An exhaust supply line  13  from exhaust outlets  14  on each valve slice  2  is also connected to the selection valve  12 . 
   The selection valve  12  is a 3 port, 2 position spool valve of known construction that controls the flow path from the supply lines  9 ,  13  to a nozzle  15 . Thus, the selection valve  12  can select the input flow path  9 ,  13  depending upon the condition and operation of the valve island  1 . The selection valve  12  is biased so that by default the turbine  7  is driven by fluid from the input supply line  9 . The selection valve  12  is actuated by a solenoid  29 . 
   Fluid leaving the selection valve  12  passes through the nozzle  15 , which is designed to direct the fluid flow toward the turbine  7 . Further, the diameter of nozzle  15  is calculated to ensure that the volume of air allowed to flow through it, and impinge upon the turbine  7 , is sufficient to generate the electricity requirement of the valve island  1 . The turbine  7  comprises a circular disc  16  having curved blades  17  that extend radially from its axis, and are raised from the disc  16 . A spindle  18  extends longitudinally from the axis of the turbine  7  and forms an armature of an electrical generator  19 . The electrical generator  19  is of known construction, with the armature  18  rotating within a cylindrical housing  20  having permanent magnets  21  mounted to its inside surface. 
   The generator  19  generates an alternating current, which is rectified by a rectifier  22 . The accumulator  6  receives the direct current (DC) output from the rectifier  22 . The accumulator  6  stores the electricity generated by the generator  19  and may comprise a capacitor or a chargeable battery. There are two output lines  23 ,  24  from the accumulator. The first output  23  supplies the solenoid  29  of the selection valve  12  with power while the second output  24  supplies power to a control means  27 , a communication means  28  and ultimately each valve slice  2 . 
   The communication means  28  includes an antenna  34  that receives signals from a remote management system (not shown) that may wirelessly control many valve islands and other systems on production machinery, for example. The communication means  28  uses any suitable communications standard to communicate with the management system, such as industrial Bluetooth or ZigBee. The communication means receives its electrical power from the accumulator  6  via power line  24 . 
   The control means  27  is connected to the communications means  28  and obtains its electrical power therefrom. The control means  27  comprises a printed circuit board that interprets the control signals received from the communication means  28 . The control means  27  then sends the appropriate signals to each solenoid  32  on each valve slice  2  to achieve the desired operation. The control means  27  may span the length of the valve island  1  over the valve slices  2 . 
   The valve slice  2  comprises a body  30  that includes the supply input port  11 , the exhaust ports  14 , output ports  31  and a solenoid  32 . The solenoid  32  receives electrical power from the control means  27  when it is to be actuated and is connected thereto by wires (not shown). The valve slice  2  contains a spool valve, actuated by the solenoid  32 , that controls the flow between the input port  11  and the output ports  31 . 
   When installing the valve island  1  the output ports  31  of each valve slice  2  are appropriately connected to the devices (not shown) that the valve island  1  controls. The valve island  1  then only requires the pneumatic supply line  8  to be connected for it to operate. In  FIG. 2 , the valve island is shown in its start-up state, in the absence of electrical power. The selection valve  12  is in its default position wherein the input supply line  9  is shown in communication with nozzle  15 . The flow of air from the input supply line  9  thus initially powers turbine  7 . Once the accumulator  6  has been supplied with sufficient power from the generator  19 , the solenoid  29  of the selection valve  12  receives the electrical power required to actuate the valve  12 . Thus, once the input fluid flow has generated the initial power requirement, the selection valve  12  switches to enable the power generation means  5  to use exhaust air from the valve slices  2  to generate electricity for the valve island  1 . This is advantageous, as once the power generation means  5  has generated enough electrical power, the valve island  1  operates without any effect upon the input pneumatic pressure. 
   Operational instructions for the valve island  1  are received wirelessly through antenna  34  by the communication means  28 . The instructions are passed to the control means  27 , which interprets the instructions and supplies electrical power to the valve slice solenoids  32  as required to actuate the valves (not shown). 
   If for instance there is a drop in the flow of exhaust air from the valve slices  2 , less air will be available to drive the turbine  7  and thus less electricity will be produced. When the solenoid  29  of the selection valve  12  is not supplied with sufficient electricity the biasing of the valve  12  causes it to switch to its default position wherein the input supply line  9  is in communication with nozzle  15 . The air flow from the input supply line  9  then powers turbine  7  to ensure that the communication means  28 , control means  27  and valve slice solenoids  32  have an uninterrupted supply of electricity. The valve island  1  continues to be powered from the input supply line  9  until once again sufficient power is generated for the solenoid  29  to switch the selection valve  12  to receive air from the exhaust air line  13 . 
   The biased selection valve  12  also ensures that if the pneumatic air line  8  is shut down or the flow is reduced, the selection valve  12  defaults to a position that allows the valve island to be “restarted” without user intervention. 
   In a modification (not shown) the selection valve is omitted and the input supply line  9  is permanently connected to the nozzle  15 . Thus, the power generation means  5  only uses the flow of air from the input supply line  9 . In a further modification (not shown) the input supply line  9  is omitted as well as the selection valve  12 . The pneumatic supply line  8  does not branch and is connected directly to the input port  11  via the manifold (not shown). The exhaust air supply line  13  is connected directly to the nozzle  15  so that the exhaust air is used to generate electricity. In this modification an initial power source (not shown) is required to generate the initial power requirements for the communication means  28  and the control means  27 , until there is sufficient air flow through the valve slice  2  and out to the exhaust supply line  13 . Thus, the initial power source (not shown) only provides the power required for the valve island to start functioning and enable a flow of air through the valve island  1 , after which the air flow from the exhaust supply line  13  can be used to power turbine  7  and generate electricity. The initial power source may be a compressed fluid vessel that is adapted to exhaust through the turbine  7  thus generating electricity. The valve island  1  may have means for recharging the compressed fluid vessel with the compressed air from the pneumatic supply line  8 . Alternatively, the initial power source may be, for example, a battery that powers the control means  27  and communication means  28  directly, until the flow of air through the exhaust supply line  13  is sufficient to generate the power requirement of the valve island  1 . The battery may be rechargeable and thus may receive an output from the accumulator  6 , which is used to recharge the battery once the power generation means  5  is generating electricity from the exhaust air.