Electronic Monitoring and Control Solutions
Automatic Changeover Unit - ACU2
For ACU Technical Information Click Here
What is an ACU2 Monitor ?
The ACU2 is designed to ensure that you never run out of gas supply no matter the application. This versatile system can accommodate dual gas manifold panels, manifold process panels, single gas cylinders, cylinder packs, or dewars, making it suitable for various setups. To integrate the ACU2, you will require two pneumatically operated valves (not included) and two pressure sensors (not included) this can include pressure switches or contact switch gauges fitted inline with each gas supply. This simple yet effective configuration guarantees continuous gas availability for your needs worry free.
In Operation in Service
The ACU 2 will monitor the sensor inputs and provide pneumatic pilot pressure to the relevant valve.
We will refer to the system as having a Side A and a Side B
Initially you will have a full gas cylinder on Side A and Side B with BOTH cylinder valves OPEN.
The ACU 2 will detect that the signals from SG A and SG B are in a healthy condition as the needles on the gauges will be above their mechanical setpoints.
If you initially placed the ACU 2 into Service Mode on Side A, doing this will open the pneumatic valve VA (VB is closed) which allows gas to flow from cylinder A only.
A side in Service, pressure gauge SG A is in healthy condition and valve VA is Open
B side is 'Available for Gas' as gauge SG B is in healthy condition and valve VB is closed.
As your gas supply depletes from cylinder A, the gauge SG A will fall below its mechanical setpoint thus changing the signal which the ACU 2 will detect and trigger an alarm for Low Cylinder A.
The valve on side A (VA) will close and the valve on side B (VB) will open so that you still have gas supply.
The cylinder on side A will require replacing, once this has been completed and leak checked you will then open the cylinder valve on your new gas cylinder and the ACU 2 will see that a healthy signal has been restored on side A.
You will then be able to make side A 'Available' for subsequent automatic changeover.
When the signal from side B gauge SG B depletes below its mechanical setpoint the signal will change state and the ACU 2 will detect the change of state and will alarm for Low Cylinder B, the valve on side B (VB) will close and the valve on side A (VA) will Open.
The logic outlined above is equally applicable to liquified process gas weight if a cylinder scale platform with digital alarm output is used.
This will ensure an uninterrupted supply of gas to your process.
£1,998 + VAT
(Wallmount variant)
(see Mounting Solutions Page)
Basic Concept of Operation . . .
You require two suitable pneumatically actuated valves and two sensors (contact switch gauges are often used) the sensors should be such that when in good condition (the pressure is above the mechanical setpoint the switch contact is Normally Closed (N/C) and as the pressure falls below the mechanical setpoint the signal from your sensor should go Open Circuit (O/C) Each of your two sensors are to be wired into the ACU 2 Controller and your two pneumatically actuated valves will be connected pneumatically to the ACU 2 Controller with suitable pneumatic tube (not supplied) We can supply various pneumatic fitting for different pneumatic pipe (please see the ACU Technical Page for the available options
Changeover Action
The ACU 2 has an easily adjustable jumper inside which will change the way in which the pneumatic valves react in the event of an automatic changeover . . .
In logic 0-1 position in the event of an automatic changeover the valve that was in service will close and then the valve going into service will open
In logic 1-0 position the valve going into service will open and then the valve which was in service will close, this is to suit different applications and lengths of gas supply line.
As with all of our controllers they are super-easy to operate with no programming required, A volume adjustable sounder with a multitude of different tones to choose from if required
There are isolated form C Volt-Free output relays for Low Cylinder A, Low Cylinder B, In Service Side A, and In Service Side B
which you can connect to for remotely monitoring the status of your unit or connect to a BMS.
The ACU 2 also comes with a full colour operation manual as well as a standard wall mounting kit
If you want to mount the ACU 2 to a cabinet / gas cabinet please take a look at our cassette system mounting brackets
Shutdown Button Shroud
An optional Shutdown Button Shroud is available
A shroud will help eliminate accidental pressing in of the Shutdown button and will also give you the option of then fitting an optional padlock to the shroud so that once the Shutdown button is pressed in a padlock can be inserted into the shroud which will prevent the pneumatic valve from opening which is an addition safety interlock for when you are performing maintenance on your equipment when safety is paramount
£49 + VAT
£17 + VAT Random Keylock
£19 + VAT matching Keylocks
Random keylocks are a different key for each padlock
Matching Keylocks are 1 key fits all padlocks
Other Mounting Options . . .
If you are requiring an alternative mounting option for example you want to mount your unit onto an enclosure / gas cabinet / shelving system then don't worry we also have you covered ! Please take a look at our Mounting Solutions page where you will find our Stainless Steel mounting Cassette Systems.
Inter-Connection Enclosures
If you are looking for a method of extending your sensor wiring to your ALU or looking for a way of connecting a series of sensors to give you single signals out to your Designed Electronics product then please check out our Inter-Connection Enclosures on our Accessories Page
Ordering an ACU2
If you are wishing to place an order for an ACU2 please head over to our ACU Technical Page for further information regarding various options and ordering codes - if you require further information or are unsure please contact us below and we will be happy to help