Vacuum pumping device with electronic control of the motor
AssigneeVarian, Inc.
InventorsRoberto Carboneri, Mario Busso
Life of this patent
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Abstract
An oil mechanical vacuum pump, which is equipped with an electric motor comprises an electronic control device for supplying the electric motor with power. The electronic control device comprises a frequency converter for controlling the excitation frequency Fecc of the voltage signal SU by which the motor is powered as a function of at least one operating parameter of the pump and of at least one threshold value that can be modified depending on the operating conditions of the pump.
Claims14
A vacuum pumping device for evacuating a chamber (CV), said vacuum pumping device experiencing in use a plurality of different identifiable operating phases, comprising:
- an oil mechanical pump (P) comprising:
- a housing (1) with a suction port (3) and a discharge port (5), the housing having a cylindrical chamber (7) and a rotor (9) disposed eccentric with respect to said chamber (7) said rotor having radial vanes (11), loaded by springs (13), said housing being equipped with an electric motor (M) for rotating said rotor (9);
- an oil bath (15), with said oil mechanical pump being immersed therein;
- and
- an electronic control device (C) for supplying said electric motor (M) with power by a voltage signal SU, said electronic control device (C) comprising:
- a frequency converter, which controls an excitation frequency Fecc of the voltage signal SU powering said motor as a function of the value of at least a measured current drain Imeas of said (M), the variation range of said excitation frequency Fecc being in any case limited in accordance with the upper limiting value for the maximum power PMAX that can be delivered by said electronic control device (C) a different value of said upper limiting value being set for each of said plurality of different identifiable operating phases, and an oil temperature detector (17) sending to said electronic control device (C) a signal representative of the temperature of said oil bath in the vacuum pump, said plurality of different operating phases being identified in accordance with said signal representative of the temperature of said oil bath, wherein said upper limiting value takes a value Preg during a steady state operation of the pump, and a value Pstart1 during a cold start phase of the pump, wherein Preg<Pstart1, said upper limiting value takes said value Pstart1 when the temperature of said oil bath is lower than a predetermined limiting value for the temperature of said oil bath.
A vacuum pumping device for evacuating a chamber (CV), said vacuum pumping device experiencing in use a plurality of different identifiable operating phases, comprising:
- an oil mechanical pump (P) comprising:
- a housing (1) with a suction port (3) and a discharge port (5), the housing having a cylindrical chamber (7) and a rotor (9) disposed eccentric with respect to said chamber (7) said rotor having radial vanes (11), loaded by springs (13), said housing being equipped with an electric motor (M) for rotating said rotor (9);
- an oil bath (15) with the oil mechanical pump being immersed therein;
- and
- an electronic control device (C) for supplying said electric motor (M) with power by a voltage signal SU, said electronic control device (C) comprising:
- a frequency controlling an excitation frequency Fecc of the powering said motor voltage signal SU as a function of the value of at least a measured current drain Imeas of said motor (M),
- the variation range of said excitation frequency Fecc being in any case limited in accordance with an upper limiting value for the maximum power PMAX that can be delivered by said electronic control device (C);
- a different value of said upper limiting value being set for each of said plurality of different identifiable operating phases;
- and
- an oil temperature detector (17) supplies to said electronic control device (C) a signal representative of the temperature of said oil bath in the vacuum pump, said different operating phases are identified in accordance with the signal representative of the temperature of said oil bath;
- wherein said upper limiting value takes a value Preg during a steady state operation of the pump, and a succession of values Pstart1 and Pstart2 during a cold start phase of the pump, with Preg<Pstart2<Pstart1, said upper limiting value takes the succession of values Pstart1 and Pstart2 when said temperature of said oil bath is lower than a predetermined limiting value for the temperature of the oil bath.
Dependencies are inferred from the claim text.