Abstract: A method for operating a compressor including providing suction pressure measurement, final pressure measurement, throughput measurement is provided. Using a first control characteristic map a target value for a pump surge limiter is determined from one or two of the measurements, and the pump surge limiter compares the target value to the throughput measurement, wherein the pump surge limiter opens a bypass valve when the measured value falls below or exceeds the target value, such that the final pressure is lowered or the flow through the compressor is increased. In the event of failure of a measurement, a further measurement of another physical variable of the compression process, together with a measured variable that did not fail or a modification of the measured variable, is an input variable for a substitute control characteristic map, form which a substitute target value is determined.

Abstract: A method for operating a compressor and arrangement. The method includes: feeding an intake flow into an inlet of the compressor, compressing the intake flow by the compressor to give an outlet flow, introducing at least one first part flow of the outlet flow into a bypass station as first bypass flow, controlling the feeding-in of the first bypass flow from the bypass station into the inlet of the compressor, depending on operating parameters of the compressor, cooling at least one second part flow of the outlet flow, and controlling the feeding-in of the cooled second part flow as second bypass flow into the inlet of the compressor, depending on operating parameters of the compressor.

Abstract: A method for operating a multistage compressor is provided. The method includes monitoring the pump limit, wherein at least a first measurement parameter measured during operation is compared to a reference parameter. The reference parameter is characteristic of reaching the surge limit or a specific distance of the operating point from the surge limit. A multistage compressor is also provided. In order to enlarge the operating range without risking safety, it is proposed that each stage to be monitored individually for the onset of the surge.

Abstract: A method for operating a multistage compressor is provided. The method includes monitoring the pump limit, wherein at least a first measurement parameter measured during operation is compared to a reference parameter. The reference parameter is characteristic of reaching the surge limit or a specific distance of the operating point from the surge limit. A multistage compressor is also provided. In order to enlarge the operating range without risking safety, it is proposed that each stage to be monitored individually for the onset of the surge.

Abstract: A compressor includes a control unit and a model unit. The control unit determines at least two actuation values of at least two actuating elements of the compressor via a transmitted setpoint value of a parameter of the compressor from a characteristic diagram of the compressor or at least two corrected actuation values of the at least two actuating elements via a model-based theoretical setpoint value from the characteristic diagram of the compressor. The model unit determines a model-based theoretical state of the compressor via the actuation values or the corrected actuation values by using a state model of the compressor. The model-based theoretical state of the compressor is described at least with the model-based theoretical setpoint value of the parameter of the compressor. The control unit controls at least one of the actuating elements as a function of the corrected actuation value of this actuating element.

Abstract: A method for operating a compressor including providing suction pressure measurement, final pressure measurement, throughput measurement is provided. Using a first control characteristic map a target value for a pump surge limiter is determined from one or two of the measurements, and the pump surge limiter compares the target value to the throughput measurement, wherein the pump surge limiter opens a bypass valve when the measured value falls below or exceeds the target value, such that the final pressure is lowered or the flow through the compressor is increased. In the event of failure of a measurement, a further measurement of another physical variable of the compression process, together with a measured variable that did not fail or a modification of the measured variable, is an input variable for a substitute control characteristic map, form which a substitute target value is determined.

Abstract: A method for operating a multistage compressor is provided. The method includes monitoring the pump limit, wherein at least a first measurement parameter measured during operation is compared to a reference parameter. The reference parameter is characteristic of reaching the surge limit or a specific distance of the operating point from the surge limit. A multistage compressor is also provided. In order to enlarge the operating range without risking safety, it is proposed that each stage to be monitored individually for the onset of the surge.

Abstract: A method for monitoring the efficiency of a compressor is provided. A mass flow, an entry pressure, an exit pressure, an entry temperature, and an exit temperature of the process medium are all determined and a performance factor is ascertained. At the inlet of each stage, a stage entry temperature and a stage entry pressure are directly or indirectly measured as measurement parameters. At the outlet of each stage, a stage exit temperature and a stage exit pressure are directly or indirectly measured as measurement parameters. Each stage is assigned a module which calculates a stage efficiency as a performance factor from the measurement parameters using a calculation means.