A fluidic device for providing analogue output control includes a main channel, a first control channel, a second control channel, a comparator which receives respective input fluid flows from the main, the first and the second control channels. The first control channel is configured such that the input fluid flow therefrom carries an oscillating pressure wave signal, the second control channel includes a flow regulator controllable to vary the mass flow rate of the input fluid flow from the second control channel, and the main channel is configured such that the input fluid flow therefrom is at a reference mass flow rate. The comparator is configured such that the input fluid flows from the first control and the second control channels act in combination on the input fluid flow from the main channel to produce an output fluid flow from the comparator having a PWM mass flow rate characteristic.

An apparatus for the production of air gases by the cryogenic separation of air can include a cold box having a heat exchanger, and a system of columns; a pressure monitoring device; and a controller. The cold box can be configured to receive a purified and compressed air stream under conditions effective for cryogenically separating the air stream to form an air gas product. The apparatus may also include means for transferring the air gas product from the cold box to an air gas pipeline. The pressure monitoring device is configured to monitor the pipeline pressure, and the controller is configured to determine whether to operate in a power savings mode or a variable liquid production mode. By operating the apparatus in a dynamic fashion, a power savings and/or additional high value cryogenic liquids can be realized in instances in which the pipeline pressure deviates from its highest value.

A fluidic device for providing analogue output control includes a main channel, a first control channel, a second control channel, a comparator which receives respective input fluid flows from the main, the first and the second control channels. The first control channel is configured such that the input fluid flow therefrom carries an oscillating pressure wave signal, the second control channel includes a flow regulator controllable to vary the mass flow rate of the input fluid flow from the second control channel, and the main channel is configured such that the input fluid flow therefrom is at a reference mass flow rate. The comparator is configured such that the input fluid flows from the first control and the second control channels act in combination on the input fluid flow from the main channel to produce an output fluid flow from the comparator having a PWM mass flow rate characteristic.

An apparatus for the production of air gases by the cryogenic separation of air can include a cold box having a heat exchanger, and a system of columns; a pressure monitoring device; and a controller. The cold box can be configured to receive a purified and compressed air stream under conditions effective for cryogenically separating the air stream to form an air gas product. The apparatus may also include means for transferring the air gas product from the cold box to an air gas pipeline. The pressure monitoring device is configured to monitor the pipeline pressure, and the controller is configured to determine whether to operate in a power savings mode or a variable liquid production mode. By operating the apparatus in a dynamic fashion, a power savings and/or additional high value cryogenic liquids can be realized in instances in which the pipeline pressure deviates from its highest value.