PERFORMANCE TESTING PROCEDURE FOR CENTRIFUGAL PUMPS DOC NO:QA02-WP13-01 REV NO:2 DT: 22-10-2007 1. SCOPE:
This procedure is applicable for testing of centrifugal pumps of Mather and Platt Pumps Ltd., Pune. The test procedures, in general, conform to relevant national / international standard specifications.
2. REFERENCE:
IS 9137 – 1978: Code for acceptance tests for centrifugal mixed flow & axial pumps –
class ‘C’
3. PROCEDURE:
3.1 PERFORMANCE TESTS:
Two types of tests are carried out. a. HYDRAULIC PERFORMANCE:
The hydraulic characteristics of the pump are established by measuring the discharge, total head, efficiency; power absorbed which constitute the operating parameters. Based on test results, curves of total head, efficiency, power absorbed will be plotted against capacity. (Sample test sheets QA02-WP13 Annex-1 performance and NPSH test when applicable, QA02-QA02-WP13 Annex-II List of applicable standard for flow measurement).
b. MECHANICAL PERFORMANCE:
The mechanical performance of the pump is established, by running the pump at duty condition for a period of one hour & pump bearing
temperature, vibrations & noise levels are observed at the end of test. The vibration & noise level will be measured on our test bed and it will be only for the reference purpose & will not be the criteria for acceptance / rejection of the pump.
3.2 MEASUREMENT OF PARAMETERS: a. FLOW MEASUREMENT:
The flow measurement is carried out either by orifice plate or magnetic flow meter, depending upon flow rate to be measured. Required straight lengths of pipes are provided as recommended for this application. The flow rate can be varied by means of valves fitted on discharge side of pumps.
i. FLOW MEASUREMENT BY ORIFICE PLATES:
For measurement of pump discharge thin square edged orifice plate of suitable geometry will be utilized. These have been installed in accordance with the re-commendations of relevant national / international standards. The applicable standards indicated in the Annexure II. The pressure drop across the orifice plate will be measured by means of differential mercury manometer. All the calculations pertaining to the computation of flow rate will be based on the guidelines given by the applicable standard.
ii. FLOW MEASUREMENT BY FLOWMETERS:
For measurement of pump discharge, magnetic induction type flow meters have been installed in the pipelines. These installations conform to the recommendations of ISO Technical Report as indicated in the Annexure II. The flow rates up to 30,000 m3/hr can be measured with the help of these installations
b. HEAD MEASUREMENT :
For measurement of head on delivery side, a calibrated bourdon type pressure gauge will be used. In case of low head pumps mercury
manometer will be used. In case of horizontal pumps, the positive suction head will be measured by a calibrated Borden type pressure gauge and negative suction head will be measured by mercury manometers.
c. SPEED MEASUREMENT:
The actual running speed of the pump will be measured with the help of a digital non-contact type tachometer.
d. ELECTRICAL MEASUREMENT:
i. INPUT POWER MEASUREMENT:
For measurement of power, two-wattmeter method will be adopted. A calibrated wattmeter suitably connected through a change over switch in connection with suitable CT’s and PT’s will be used.
ii. VOLTAGE AND CURRENT MEASUREMENT:
The supply voltage and current will be measured through CT’s and PT’s by means of calibrated voltmeter and ammeters.
3.3 COMPUTATION OF TEST RESULTS:
The various readings, observed as above, will be recorded in standard pump test sheet and based on these, calculations shall be carried out as shown below.
As speed of motor at the time of testing varies with load, pump performance is converted to rated motor speed using affinity laws. A copy of standard pump test sheet is also enclosed herewith, as an Annexure I.
a. SYMBOLS:
Q – Flow through pump - M³/hr TDH – Total discharge head - mWC Hs – Suction head - mWC
Hd – Discharge head - mWC α – Gauge level difference - mWC Dd – Discharge pipe ID – m
Ad – Area of discharge pipe - m²
Vd – Velocity through discharge pipe - m/sec Ds – Suction pipe ID - m
As – Area of Suction pipe - m²
Vs – Velocity through suction pipe – m/sec
∆ H – Difference in columns of Hg manometer – mm W1 – Wattmeter reading W2 – Wattmeter reading V – Voltage - V I – Current - amps KW – Power absorbed η m – Efficiency of motor η p – Efficiency of pump K – Orifice constant Pout – Pump output in kW Pin – Pump input in kW b. CALCULATIONS:
Refer test sheet A.
i. Qm = K.\c∆ H - For orifice plate = Reading for display - for magnetic flow meter ii. Velocities Vs = Q/As Vd = Q/Ad TDHm = Hd ± Hs + (Vd²/2g - Vs²/2g) + α iii. P out = TDH × Q / 367.2
iv. Motor input = (W1+W2) × Wattmeter constant
v. Motor output = Motor input × η m = Pump input (Pin) vi. Pump efficiency = η p = Pout/ Pin.
B. Conversion to rated speed as per affinity laws. K2 = Rated speed / Measured speed
Q = Qm × K2 TDH = TDHm × K2² P = Pin × K2³
c. INSTRUMENT SPECIFICATION:
Description Instrument Overall Accuracy
Discharge Electromagnetic Flow meter & or Orifice
Uncertainty limits as per IS: 2952 (PART-1) for Orifice plate & ISO: TR 6817 for
Head Bourdon type Pr.
Gauge ± 0.5% of full scale reading
Power Watt meter ± o.5% of full scale value
Speed Tacho meter ± 1 rpm 4. VERIFICATION GUARANTEES:
Standard IS 9137 CLASS C
Quantity Permissible limit, %
Rate of flow +7.0%
Pump total head +4.0%
Pump efficiency -5.0% 5. DOCUMENTATION: a. Performance test sheet.
b. Instrument calibration – Records can be verified at the time of Performance testing.
c. Wherever provided job motor routine test certificate can be verified at the time of Performance testing.
6. RECORDS OF REVISION:
REV
NO. REVISION DATE DETAILS OF REVISION PREPARED BY HOD (QA) HOD (TEST LAB)APPROVED BY 0 1 2 01-06-2003 12-01-2004 22-10-2007
New issue with new procedure as per
ISO 9001:2000 Document No changed from
QA02-WP33 to QA02-13-01 Annexure-I replaced with new test
