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Electrically actuated or motorised ball valves offer an ideal high unrestricted flow solution for On/Off or Open and Closed media control by pure electrical power supply and are ideally suited to applications where there is no compressed air supply or where the media and application is incompatible for using a solenoid valve.
An electrically actuated ball is basically a standard lever ball valve with an electric motor and gear box mounted above it to open and close the valve. It is quite common for the connection between the motor and valve to be standardised so that various motors and valves can be assembled together, this standardised mounting method is known as ISO5211.
A typical motor actuated valve will move (Open or close) when energised (electrically powered) and stay put (not move) when power is removed, typical voltages 12vDC, 24vDC, 24vAC, 110vAC and 230vAC with either IP65 or IP67 ingress protection. Some intelligent actuators can accept multiple voltages such as the Mini 5 Watt 5 second ABVM and the larger ABV 22 watt 15 second unit where both can accept either 9 to 24 volt ACDC or 110 to 250vAC voltages.
Failsafe actuated valves that self return with no power by means of an electrical power reserve are especially useful. The key element with this construction is that upon power failure the motorised valve will utilise its reserve power to close without the need of any other control or power source, much like a fail-safe solenoid valve.
Proportional actuated valves offer proportional opening and closing by means of an additional 4-20 mAmp controlling voltage whereby half the control voltage say 12 mAmp would give 50% opening, 16 mAmp 75%. With each additional 1 mAmp control voltage offering an additional 1/16th (6.25%) opening of the valve. This can be quite useful if users wish to remotely control the amount of flow through a process valve rather than simply fully open or fully closed.
Most European standard electric or pneumatically operated actuators will conform to the European ISO5211 standard, which is a universal dimensional standard for part turn actuators and process valve mounting with or without gearbox. For example an actuator with ISO5211 mounting size F03 will fit directly onto an ISO5211 F03 industrial valve. The Size F denotes the size so F03 being the smallest and F60 the largest, as different types of industrial valves require different turning force or torque to actuate / turn them.
|The table below shows the accepted European Standard for ISO5211 dimensions.|
Most valve manufacturers or valve suppliers will advise the amount or torque or force required rotate the valve. Torque is defined as Force "F" applied at a distance "r" from an axis or pivot point and is typically measured in Newton Meters or Nm which is measured as the resulting twisting force torque from applying 1 newton force F or weight at the end of a lever r 1 meter long.
1 Newton meter = 0.737 foot pounds
1 kilogram force meter = 9.8 Nm
So when using an ISO5211 mount process valve that requires 5000 Nm or torque you can see from the ISO5211 table above that the actuator required for the job would be the ISO5211 F25, you cannot use the F16 as the maximum torque 4000 Nm is insufficient to meet the demands of the valve to be used. Using the correct ISO F25 actuator and valve ensures they will connect correctly and the actuator exceeds the requirements of the valve without being over loaded. ALWAYS choose an actuator with sufficient or at least equal to the torque required.
Helpful Hint: It is however best practise to purchase your valve and actuator already assembled and function tested, this remove the need for tools and assembly but more importantly that the actuator and valve fully open and close correctly without the need to make internal actuator open/close limit adjustments.
External valve position indication typically an arrow or line that will give a visual representation of the state (open or closed) of the valve being controlled.
Internal volt free switches inside the actuator that can be connected to a remote control panel for electrical position open and closed status feedback.
Electrical heaters to prevent icing or freezing of the valve actuator in particularly cold environments and with thermal switches to protect from over heating within the motor housing. The thermal heater draws energy from the actuator power supply.
Standard electrically actuated valves will stay put i.e. not move if electrical power is removed, however in some applications users require for safety reasons a fail-safe close or fail safe return when power is lost or removed. One way to achieve this is to provide a battery pack with the electric actuator to provide the back up power supply for the electric motor. These can work well for a time but like all rechargeable batteries they have a limited life expectancy and will require a long initial charge before being ready. They can be expensive and require external wiring, additional care and space.
Actuated ball, gate, butterfly, globe or butterfly valve electric actuators are sometimes fitted with a manual override system to allow engineers or valve users to manually open or close the valve by means of either a hand wheel for large actuators or for small electric actuators a small exposed square drive shaft located under the electric actuator housing. These typically will require several turns to fully open or fully close the actuator depending on size and design. The larger more powerful actuators will require more force or torque to move so the manual system will typically be geared down requiring more turns for reduced applied manual force but this can be compensated to a degree by having larger hand-wheels.
Standard electrically actuated motorised valves will stay put (not move) when power is removed and sometimes users require the valve to automatically return to a default failsafe position if power is removed. One way to achieve this is with an internal spring mechanism or spring return to provide the energy required to rotate the valve back to a fail safe position without electrical power supply. These have advantages over battery back up systems as the spring is integral within the actuator motor housing, but because the motor has to work against this return spring as well as the valve itself it requires a much bigger more powerful (higher torque) motor or additional gearing that will in turn increase actuation time.
Most standard electrically actuated valves are either open or closed, i.e. fully in one or the other position, but some applications require partial opening i.e. 50% open or 25% open. This is achieved with a modulating actuator that opens according to a separate control voltage either 0 to 10 volts or more commonly 4 to 20 mAmp. For example 240vac actuated ball valve with 230v AC 50/60 Hz mains supply with 8 mAmp control signal will be 50% open, 4 mAmp 25% open and 2 mAmp 12.5% open etc offering complete analogue valve position.
A fail safe actuator electronics offer fast reliable fail-safe reliable actuator return even when mounted to a 2" BSP or NPT 304 or 316 stainless steel ball valve. Encompassing advances in motor technology and electronics have allowed the development of a technically less expensive small compact reliable control systems including standard 3 wire control and fail safe return control mechanisms. The ABVM miniature 1/2 3/4 and 1" blue electrically actuated ball valve on the left require only 5 watts to open or close in under 5 seconds. The failsafe return option requires only 30 second initial (out of the box) charge period to provide sufficient power to self close or return to original position. Supplied complete with visual position indicator and options for open and closed position feed back and for low voltage model manual over ride facility. The ABV 11/4, 11/2 and 2 " BSP/NPT threaded white ball valve on the right requires only 22 Watts and 12 seconds to open or close and can be supplied as standard 3 wire power open power close and failsafe return (internal battery), supplied with visual position indication and additional option for open and closed position feed back.
Further advances in electronics have allowed for a huge voltage ranges for each actuator head so users can choose either either the 9 to 24 volt AC/DC actuator or the 110 to 250 volt AC actuator. Both actuators are available as standard mount to 2 piece 2 way 304 stainless steel full flow ball valves, however 316 stainless steel, brass or PVC-U 2 or 3 way valves can also be used when mounting these actuator heads.
The CNX20 20Nm compact ISO5211 15 second IP67 brushless actuator is the smallest most cost effective high end quality electric actuator in the UK market today. This little actuator fits into the palm of your hand and its strong brushless 20NM motor can drive a two inch 2pc WRAS approved full flow ball valve up to 2" BSP.
Packing more punch size for size than any other actuator on the market today. This reliable motorised head is not only strong and reliable but can also be supplied with failsafe option so that it will return any ISO5211 valve it is mounted to back to its original failsafe position without the need for electrical power. THis is achieved with an internal back up power supply (battery) that is charged during use, typically requires only 30 seconds for its initial first use.
The CNX-S is the SMART or intelligent version of the standard actuator, typically only an additional £130 more the smart version has an LED screen with button controls for manual over ride, dead band adjustment, speed control, closed position and reverse action adjustment as standard. Additional options available with the SMART CNX-S actuator include:
Modulating 4-20mAMP (CNX20SM), Wireless control (CNXSW), Modbus Control (CNX20SMB), 24vDC High speed actuator (SNX20SHS) and finally Timer Control Actuator (CNX20ST).
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