US 9,228,590 B2Granted

Method for controlling a compressor element of a screw compressor

AssigneeAtlas Copco Airpower, Naamloze Vennootschap

InventorsJohan Nachtergaele, Simon Peter G. De Bock

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Abstract

Method for controlling a compressor element of a screw compressor, where the compressor element has a housing with two meshing helical rotors supported in the housing in the axial direction using at least one axial bearing. The method has a process A and/or a process B, where process A has a first step of switching on a first magnet during start-up of the compressor element, such that the magnet exerts a force on the rotor that is directed from an outlet side to an inlet side, and of switching off this first magnet during nominal operation of the compressor element; and where process B has a first step of keeping a second magnet switched off during start-up of the compressor element, and switching on this second magnet during nominal operation of the compressor element, such that this second magnet exerts a force that is directed from the inlet side to the outlet side.

Claims27

Dependent claims

Method for controlling a compressor element of a screw compressor, said compressor element having a housing, two meshing helical rotors positioned in the housing, each helical rotor having a shaft with a helical rotor body, wherein the shaft of each helical rotor is supported in the housing along the axial direction by at least one axial bearing, and wherein the housing is provided with an inlet for a gas to be compressed at one end of the helical rotors and an outlet for the compressed gas at the other end of the helical rotors, said method comprising the steps of:

providing the compressor element with a device configured to exert an extra force on the at least one axial bearing via the rotor, wherein the device configured to exert the extra force comprises at least one of a first magnet and a second magnet, said at least one magnet having a magnetic field exerting a force acting in the axial direction on at least one of the helical rotors of the compressor element or on an outer race of a second bearing that is affixed around the helical rotor,
wherein said force of said magnetic field of the at least one magnet is selectively operative depending on the mode in which the compressor element is operating;
and
employing the force of the at least one magnet according to at least one of the following processes:
a process A comprising a first step of employing the force of the magnetic field of the at least one first magnet during start-up of the compressor element such that said first magnet exerts a force on at least one of the helical rotors directed from the outlet side to the inlet side, and rendering inoperative the force of the magnetic field of said first magnet during nominal operation of the compressor element, and
a process B comprising a first step of maintaining the force of the magnetic field inoperative of the at least one second magnet from at least one of the helical rotors during start-up of the compressor element, and employing the force of the magnetic field of the second magnet during nominal operation of the compressor element such that the second magnet exerts a force on at least one helical rotor directed from the inlet side to the outlet side.

3 more elements

providing the compressor element with a device configured to exert an extra force on the at least one axial bearing via the rotor, wherein the device configured to exert the extra force comprises at least one of a first magnet and a second magnet, said at least one magnet having a magnetic field exerting a force acting in the axial direction on at least one of the helical rotors of the compressor element or on an outer race of a second bearing that is affixed around the helical rotor,
wherein said force of said magnetic field of the at least one magnet is selectively operative depending on the mode in which the compressor element is operating;
and
employing the force of the at least one magnet according to at least one of the following processes:
a process A comprising a first step of employing the force of the magnetic field of the at least one first magnet during start-up of the compressor element such that said first magnet exerts a force on at least one of the helical rotors directed from the outlet side to the inlet side, and rendering inoperative the force of the magnetic field of said first magnet during nominal operation of the compressor element, and
a process B comprising a first step of maintaining the force of the magnetic field inoperative of the at least one second magnet from at least one of the helical rotors during start-up of the compressor element, and employing the force of the magnetic field of the second magnet during nominal operation of the compressor element such that the second magnet exerts a force on at least one helical rotor directed from the inlet side to the outlet side,
wherein the at least one magnet has a north-south axis oriented parallel to the axial direction of the helical rotors.

4 more elements

providing the compressor element with a device configured to exert an extra force on the at least one axial bearing via the rotor, wherein the device configured to exert the extra force comprises at least one of a first magnet and a second magnet, said at least one magnet having a magnetic field exerting a force acting in the axial direction on at least one of the helical rotors of the compressor element or on an outer race of a second bearing that is affixed around the helical rotor,
wherein said force of said magnetic field of the at least one magnet is selectively operative depending on the mode in which the compressor element is operating;
and
employing the force of the at least one magnet according to at least one of the following processes:
a process A comprising a first step of employing the force of the magnetic field of the at least one first magnet during start-up of the compressor element such that said first magnet exerts a force on at least one of the helical rotors directed from the outlet side to the inlet side, and rendering inoperative the force of the magnetic field of said first magnet during nominal operation of the compressor element, and
a process B comprising a first step of maintaining the force of the magnetic field inoperative of the at least one second magnet from at least one of the helical rotors during start-up of the compressor element, and employing the force of the magnetic field of the second magnet during nominal operation of the compressor element such that the second magnet exerts a force on at least one helical rotor directed from the inlet side to the outlet side,
wherein the at least one magnet contains a seal with a gas-sealing function between the rotor and the housing.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/807,818Filed 1 Jul 2011
Priority: BE 2010/03972 Jul 2010
Published: US 2013/0101390 A125 Apr 2013
Granted: 5 Jan 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

F04D 27/00
Control
F04C 18/16
With toothed rotary pistons: with helical teeth, e.g. chevron-shaped, screw type
F04C 29/0021
Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00: systems for the…
F04D 27/02
Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids: surge control