Controlling a vacuum system comprising a vacuum generator arrangement
AssigneePiab Aktiebolag
InventorsGustaf Wigren, Peter Engborg
Life of this patent
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Abstract
The invention relates to energy saving in vacuum systems by means of a method and a controller enabling to consider the fluctuation in system-pressure of a system by determining a maximum system-pressure S2H and a minimum system-pressure S2h for each working cycle WC based on a determined target system-pressure pn− and a pre-set system-pressure p0− for the current working cycle WCn (n=1, 2, 3, . . . ). The method is especially adapted to fluctuations in system-pressure level of a vacuum system comprising a vacuum gripper tool.
Claims14
A method for automatic pressure level determination and adaptation enabling energy saving in working cycles in a vacuum system operating a vacuum gripper tool for transportation of objects, said vacuum system comprises a vacuum generator arrangement driven by a compressed air flow, wherein the vacuum generator arrangement via a vacuum chamber being part of the vacuum system is arranged to be brought in flow connection with the vacuum gripper tools, in order to supply vacuum to the vacuum gripper in result of the compressed air flow, wherein a pressure sensor for monitoring a system-pressure p−(t) is arranged inside the vacuum chamber;
- and a vacuum system controller being electrically connected to a main controller, wherein the vacuum system controller is arranged to control and communicate with the vacuum generator arrangement and communicate with the pressure sensor, and the vacuum system controller is arranged to monitor the measured system-pressure p−(t) continuously, wherein the vacuum system controller further is capable to calculate a system-pressure time derivative D(t)=dp−/dt during the working cycles, wherein the method comprises the steps of:
- determining at start-up of a working cycle value D0 of the system-pressure time derivative at a pre-set system-pressure p0−;
- calculating value Dtarget of target system-pressure time derivative using the value D0;
- comparing the system-pressure time derivative D(t) to Dtarget until D(t) equals Dtarget;
- determining a target system-pressure pn− where D(t) equals Dtarget;
- calculating the maximum system-pressure S2H and the minimum system-pressure S2h by means of the target system-pressure pn− and the pre-set system-pressure p0−;
- operating the vacuum generator arrangement to reestablish a vacuum system-pressure p−(t) to maximum system-pressure S2H when the vacuum system-pressure p−(t) is equal to or closely equal to the minimum system-pressure S2h.
A controller for automatic pressure level determination and adaptation enabling energy saving in working cycles in a vacuum system operating a vacuum gripper tool for transportation of objects, said vacuum system comprises a vacuum generator arrangement driven by a compressed air flow, wherein the vacuum generator arrangement via a vacuum chamber being part of the vacuum system is arranged to be brought in flow connection with the vacuum gripper tools, in order to supply vacuum to the vacuum gripper in result of the compressed air flow, wherein a pressure sensor for monitoring a vacuum system-pressure p−(t) is arranged inside the vacuum chamber;
- and a vacuum system controller being electrically connected to a main controller, wherein the vacuum system controller is arranged to control and communicate with the vacuum generator arrangement and communicate with the pressure sensor, and the vacuum system controller is arranged to monitor the measured system-pressure p−(t) continuously, wherein the vacuum system controller further is capable to calculate a system-pressure time derivative D(t)=dp−/dt during the working cycles, said controller comprising a processor in a processing circuitry being operative to perform the steps of:
- determining at start-up of a working cycle value Do of the system-pressure time derivative at a pre-set system-pressure p0−;
- calculating value Dtarget of target system-pressure time derivative using the value D0;
- comparing the system-pressure time derivative D(t) to Dtarget until D(t) equals Dtarget;
- determining a target system-pressure pn− where D(t) equals Dtarget;
- calculating the maximum system-pressure S2H and the minimum system-pressure S2h by means of the target system-pressure pn− and the pre-set system-pressure p0−;
- operating the vacuum generator arrangement to reestablish a vacuum system-pressure p−(t) to maximum system-pressure S2H when the vacuum system-pressure p−(t) is equal to or closely equal to the minimum system-pressure S2h.
Dependencies are inferred from the claim text.