Method for collecting machine vibration data

A method for predicting and detecting changes in the vibratory condition of a screw compressor, which includes at least one rotative element, said at least one rotative element having at least one key frequency, the method for predicting and detecting changes in the vibratory condition of the screw compressor, comprising the following steps:

• before permanently installing the screw compressor, collecting first vibration data for the screw compressor at a predetermined screw compressor operating state;
• compiling the first vibration data into a corresponding benchmark footprint for the predetermined operating state of the screw compressor and comparing the first vibration data with the key frequency of the at least one rotative element to determine if the screw compressor is in a desired vibratory operating condition;
• permanently installing the screw compressor at an operation site;
• storing in a memory a predetermined logic routine, which includes a fast Fourier transform algorithm, and at least one of the key frequency value of the at least one rotative element of the screw compressor;
• collecting second vibration data for the at least one rotative element at the predetermined compressor operating state;
• compiling the second vibration data into a corresponding second benchmark footprint for the predetermined operating state of the compressor and comparing the second vibration data with the stored at least one key frequency value of the at least one rotative element to determine if the compressor is in a desired vibratory condition;
• trending, at regular intervals, to determine whether the compressor vibratory condition has changed, said trending comprised of the following steps:
• switching the compressor from an actual compressor operating state and operating the screw compressor in the predetermined operating state;
• sensing the mechanical motion of the at least one rotative element during compressor operation in the predetermined operating state;
• converting the mechanical motion of the at least one rotative element into a corresponding electrical signal;
• correlating the predetermined operating state of the compressor with the corresponding electrical signal;
• inputting the corresponding electrical signal to a processor;
• processing the corresponding electrical signal into corresponding vibration data of the compressor by utilizing the predetermined logic routine;
• collecting vibration data of the compressor by storing in a memory the corresponding vibration data;
• and
• comparing the corresponding vibration data with the at least one predetermined key frequency value of the at least one rotative element of the machine and any vibration data previously collected during a previously executed trending step and stored in memory, to highlight trends in the vibratory condition of the machine and thereby determine the present condition and predict the future condition of the compressor;
• decreasing the length of the regular interval between trending steps if the compressor experiences a negative deviation in the vibratory condition;
• returning the compressor to the actual compressor operating state;
• and
• controlling the operation of the compressor in response to the determined present condition and the predicted future condition
• of the compressor by outputting a command signal from the processor to the compressor, while the compressor is operating.

A method for predicting and detecting the condition of a compressor having at least one rotative element, the method comprising the following steps:

• storing in a data memory a predetermined logic routine, which includes a fast Fourier transform algorithm;
• storing in the data memory, at least one key frequency value of the at least one rotative element for each of the different predetermined operating states of the compressor;
• switching the compressor from an actual compressor operating state and operating the compressor in a predetermined operational state;
• sensing the mechanical motion of the at least one rotative element and collecting vibration data at predetermined time intervals;
• processing the collected vibration data into at least one vibration footprint using the predetermined logic routine for each of the at least one rotative elements;
• converting each of the at least one vibration footprints to a corresponding electrical signal and storing each of the corresponding electrical signals within the data memory;
• correlating each of the previously stored at least one key frequency values at the operating state, with a corresponding vibration footprint;
• comparing each of the at least one vibration footprints with the corresponding at least one stored key frequency value to determine whether each of the at least one vibration footprints is within the acceptable range of the corresponding at least one stored key frequency value of the at least one rotative element and comparing the vibration footprints with the vibration footprints generated during previous time intervals to reveal trends in the vibratory condition of the compressor;
• decreasing the length of the regular interval between trending steps if the compressor experiences a negative deviation in the vibratory condition;
• returning the compressor to the actual compressor operating state;
• and
• controlling the operation of the compressor in response to the determination whether each of the at least one vibration footprints is within an acceptable range for the compressor by outputting a command signal from the processor to the compressor, while the compressor is operating.