Abstract: A compressor control method includes providing variable aerodynamic sizing of fluid flow through a compressor at multiple operating points of the compressor. A head is determined for an operating point, based on a process input at that operating point. Further, for that operating point, a control pressure number is determined as a function aerodynamic flow sizing at that operating point. The control pressure number is determined a function of the head divided by the square of a tip speed of the impeller of the compressor. An operating speed setpoint is determined based on the determined head and control pressure number.

Abstract: A compressor control method includes providing variable aerodynamic sizing of fluid flow through a compressor at multiple operating points of the compressor. A head is determined for an operating point, based on a process input at that operating point. Further, for that operating point, a control pressure number is determined as a function aerodynamic flow sizing at that operating point. The control pressure number is determined a function of the head divided by the square of a tip speed of the impeller of the compressor. An operating speed setpoint is determined based on the determined head and control pressure number.

Abstract: In the in-situ retorting of oil shale using radio frequency electrical energy, an applicator is inserted into a borehole and energized at a radio frequency. A protective device protects the applicator from expansion of the oil shale formation. The protective device includes an end plate attached to the applicator and a plurality of elements surrounds the applicator and is in contact with the end plate so as to prevent the oil shale formation from contacting the applicator.