The reciprocating compressor testing article provides you information about reciprocating compressor mechanical running test and reciprocating compressor thermodynamic performance test procedures. This content is supplementary article for Third Party Inspection for Reciprocating Compressor article.
This content also covers what is named reciprocating compressor factory acceptance test.
Both tests are done separately. The purpose of these tests is to verify the specified mechanical properties and the specified thermodynamic performance data of the compressor.
Reciprocating Compressor Testing - Applicable Standards
The applicable standards for these tests are:
Reciprocating Compressor Testing - Mechanical Running Test at manufacturer's shop
The following components are used from Job equipment
The following components are used from test stand
The following components are not used in the test
The compressor is assembled in test stand in manufacturer's shop. The the cylinder valves would not be installed to perform non-load continuous operation.
The compressor is operated at the specified rotating speed for 4 hours continuously and mechanical stability, temperature, pressure, vibration and noise are checked.
After 4 hours continuous operation the reciprocating compressor needs to be stopped and bearing temperatures to be measured.
Then the reciprocating compressor is diassmbled and strip down inspection is done based the requirement of inspection and test plan.
Measurement items during Mechanical running test
The rotating speed is measured by a tachometer every 30 minutes. The measurement value to be an average value of those indicated by the tachometer.
Rotating speed need to be be within of the specified rotating speed.
The supplied and discharged oil temperature of crankcase is measured by temperature gauges in the shop lube oil unit every 30 minutes.
The supplied and discharged oil temperature needs to be within specified values.
The supplied oil pressure of crankcase (bearings)and discharged oil pressure of lube oil pump are measured by pressure gauges in oil unit every 30 minutes.
The obtained values need to be in within specified values.
The vertical and horizontal vibrations of crankcase are measured at two locations by the use of a shop vibration meter. Also, the vibration at cylinder is measured with respect toaxial, horizontal and vertical directions by the use of a shop vibration meter. Vibration measurement needs to be done once during test operation.
The vibration of crankcase (peak to peak) needs to be within specified values.
The noise is measured at a distance of 1 m from the side of the main unit and four directions by using a shop noise meter. Noise measurement to be done once during test operation.
The obtained noise value need to be within specified value.
Temperature Measurement After Test Operation
The temperature for each of the following bearings just after stopping the 4-hour continuous test operation need to be measured.
The measured values need to be within specified values.
Lube Oil Console Running Test
After completion of successful oil flushing the lube oil console running test needs to be done. Running test would be performed based on the following conditions for 4 hours, and temperature and pressure shall be measured every 30 minutes.
No leakage must be seen during the test and Pressure drop of filter element shall not exceed a specified value at operating oil temperature. No abnormal sound shall be confirmed during the running test.
Tempered Cooling Water Console Running Test
After completion of successful cooling water flushing the tempered cooling water system running test needs to be done. Running test would be performed based on the following conditions for 4 hours, and temperature and pressure shall be measured every 30 minutes.
No leakage must be seen during the test and no abnormal Pressure drop must be confirmed. No abnormal sound shall be confirmed during the running test.
After checking of the above items at two times, the water pump is changed to another and the same items needs to be checked.
Reciprocating Compressor Testing - Thermodynamic Performance Test Procedure
The reciprocating Compressor thermodynamic performance test is similar to the centrifugal compressor. You may review Centrigugal Compressor Testing for detail test instruction.
Following data need to be extracted from a centrifugal compressor design book, datasheet and operating manual and to be available during the test.
Specified Operating Speeds
Maximum Shaft Vibration
Lube Oil Data
Reciprocating Compressor Testing Preparation for Mechanical Running Test
Normally a check list is used for controlling which of items are based design and actual operating condition.
The following components are used from Centrifugal Compressor Test Stand (Not Original)
The following components are used from centrifugal compressor (original)
Note: The coupling and instruments are used from both systems i.e. test stand and original components of compressor
Reciprocating Compressor Testing - Mechanical Running Test
Unfiltered and filtered displacement amplitudes and the corresponding phase angles will be recorded and plotted vs. speed during coast down. Bode plots during coast down.
After completion of the mechanical running test and after sufficient cooling-down the compressor will be checked according to the inspection and test plan.
Reciprocating Compressor Testing - Vibration Measurements
Shaft vibrations and axial displacements are measured. Vibration measurements are carried out with the vendor measuring system. All other necessary instrumentation for vibration analysis needs to be available by centrifugal compressor vendors.
For assessment of the allowable amplitudes of the shaft vibrations according to design the monitoring systems installed in the test stand are used. For visualization and preparing plots a mobile diagnostic system are used.
Run out is determined and recorded. Only these values are binding for the machine. At low speed the shaft vibration monitor only indicates the slow-roll-signal.
If the measured slow-roll-signal values during the test run exceed distinctly the specified run out values, run out are controlled and, if necessary, refurbished after completion of the test run without repeating the test run.
Reciprocating Compressor Testing - Required Data for Thermodynamic Performance Test
Following data need to be extracted from a centrifugal compressor design book, datasheet and operating manual and to be available for calculations.
Similarly the test medium and related operating parameter need to be identified. N2 normally is used as the test medium. Following also need be specified:
Test Meduim Inlet Condition
Test Meduim Discharge Condition
Reciprocating Compressor Testing - Thermodynamic Performance Test Procedure
Before starting the thermodynamic performance test the compressor is operated for a sufficient period of time at the calculated test conditions to demonstrate acceptable mechanical operation and stable values of all measurements.
All instruments are inspected separately and the measured variables in identical measuring planes are compared to each other.
The duration of the test is depending on the time needed to reach steady-state test conditions. This condition is insured by steady-state values of pressures and temperatures.
An automated data acquisition system is used. The data are recorded, processed and displayed online.
Reciprocating Compressor Testing - Measuring and Analysis
Previous to the test all measuring instruments for pressure and temperature are calibrated. On customer's request the calibration can be redone after the test for one instrument each for pressure and temperature at the inlet and discharge port.
The inlet and discharge pressures and temperatures are measured on the basis of the applicable documents.
The mass flow is measured according to BS EN ISO 5167-2
The shaft power will be calculated with the heat balance method.
For the mechanical power losses the design value is used.
The Reynolds Number correction is done in accordance to ICAAMC.
Measuring uncertainty per BS ISO 5389
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