Thrust control system for fluid handling rotary apparatus
AssigneeAcd, LLC
InventorFrank X. Andrews
Life of this patent
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Abstract
A thrust control system for fluid handling rotary machines, such as turbo expanders equipped with a magnetic thrust bearing, includes a magnetic thrust control circuit for providing a thrust signal which is a measure of the magnitude and direction of the thrust force on the thrust bearing. The rotor and stator of the machine have generally axially opposed thrust areas separated by a thrust cavity. Valves are connected between the thrust cavity and high and low pressure fluid sources. A controller, responsive to the thrust signal, controls the valves to selectively conduct fluid between the cavity and the high and low pressure sources to increase or decrease the fluid pressure in the cavity to minimize variations of the thrust force from a preset value which could be zero, for example.
Claims14
In a system for controlling the thrust on a rotary machine having a stator, a rotor mounted for rotation relative to the stator, generally axially aligned opposed thrust areas for the stator and rotor separated by a fluid receiving space with a fluid passageway communicating with the space;
- at least one thrust bearing for accepting a generally axial thrust load between the rotor and stator and thrust signal generating means for providing a thrust signal representative of the magnitude and direction of the thrust force on the thrust bearing, the combination which comprises:
- a) first and second sources of fluid under pressure with the first source being at a higher pressure level than the second source;
- b) valve means connected between the fluid passageway and the first and second sources of pressurized fluids;
- and
- c) control means responsive to the thrust signal for controlling the valve means to selectively conduct fluid from the first and second sources to the fluid receiving space to increase or decrease the pressure in said space to maintain the thrust force load on the thrust bearing at a preset value.
In a system for controlling the thrust on a thrust bearing between the rotor and stator of a fluid handling rotary machine having an inlet for receiving fluid at one pressure and an outlet for discharging fluid at another pressure, the rotor and stator having generally axially opposed thrust areas separated by a cavity and bounded at an inner and an outer circumference by radially spaced sealing means, the machine further defining a fluid passageway in communication with the cavity, the combination comprising:
- a) thrust signal generating means for generating a thrust signal which is a measure of the magnitude and direction of the thrust force on the thrust bearing;
- b) first and second sources of fluid under pressure, the first source being at a different pressure level than the second source;
- c) valve means connected between the fluid passageway and the first and second sources of pressurized fluid;
- d) control means responsive to the thrust signal for controlling the valve means to selectively conduct fluid from the first and second sources to the fluid passageway to increase or decrease the fluid pressure in said cavity to minimize variations of the thrust force from a preset value.
In a system for controlling the thrust on an active magnetic thrust bearing positioned between the rotor and stator of a turbo expander having an inlet for receiving fluid at one pressure and an outlet for discharging fluid at a lower pressure, the rotor and stator having generally axially opposed thrust areas separated by a thrust cavity and bounded at an inner and outer circumference by radially spaced sealing means, the stator defining a fluid passageway in communication with the cavity, the thrust bearing including a thrust disk armature carried by the rotor, a pair of electromagnets mounted on the stator on each side of the thrust disk, and a servo thrust control system for sensing deviations of the rotor from a nominal position and supplying current to the electromagnets to counterbalance the thrust load imparted to the rotor, the difference in current to the electromagnets representing the direction and magnitude of the force on the thrust bearing, the combination comprising:
- a) a vent valve connected between the fluid passageway and the expander outlet;
- b) a pressurization valve connected between the fluid passageway and the expander inlet, each of the vent and pressurization valves having a closed, a fully open and a partially open position;
- c) a controller responsive to the current in the thrust bearing electromagnets for controlling the vent and pressurization valves to selectively conduct fluid from the thrust cavity to the expander outlet or conduct fluid from the expander inlet to the thrust cavity to increase or decrease the fluid pressure in said cavity to minimize variations of the thrust force from a preset valve.
Dependencies are inferred from the claim text.