Patent ID: 9347285
Filing Date: 2016-05-24
CPC Classification: E21B,F04C

Claim Text:
1. Method for controlling a compressor at a rock drilling apparatus, said rock drilling apparatus including a power source for driving a first consumer at a rock drilling process, said first consumer being a compressor and said compressor being arranged to operate according to a first mode and according to a second mode, wherein, in said first mode, the work produced by the compressor is arranged to be controlled by a control device in communication with said compressor by controlling rotation speed of said compressor, and wherein, in said second mode, the work produced by the compressor is arranged to be controlled by controlling air flow at an inlet of the compressor, the method including: determining a first parameter value representing a demand of work from said compressor, controlling the compressor by the control device according to said first mode when said first parameter value representing a demand of work from said compressor exceeds a first demand, and controlling the compressor by the control device according to said second mode when said first parameter value representing a demand of work from said compressor is lower than said first demand; wherein said rock drilling apparatus includes at least a second consumer being driven by said power source, wherein the method further includes determining a lowest speed of said power source that is required for operation of said at least one second consumer, wherein control according to said second mode is performed when said first parameter value is below the work that the compressor delivers at said determined lowest speed of said power source, and wherein control according to said first mode is performed when said first parameter value equals or exceeds the work that the compressor delivers at said determined lowest speed of said power source.