Pump Monitoring & Consultancy
Pilot Study / Audit
In order to establish the business case for implementation of PumpMonitor on a given site a Pilot Study is recommended. TAS staff will inspect the site and produce a Study Report including:
Detailed analysis of available data for selected pumps with reference to their original performance curves.
General comment on status of other pumps on the site.
Projected savings in Life Cycle Costs.
Recommended data communications option.
Detailed costs and cost/benefit analysis
The following information is required for each pump installation to be monitored:
Pump model and manufacturer
The flow, head, power absorbed and efficiency from the original duty point
Service history, including maintenance and refurbishments. This is not strictly necessary but would be of major benefit in projecting savings in maintenance costs
Results of any tests done on site (either by client or OEM)
All of the above data is normally available from the pump user or can be sourced from the OEM.
For continual monitoring the following data is collected at pre-set intervals (e.g. hourly).
Suction pressure obtained via a sump level or pressure transducer transmitting a 0-10V or 4-20mA signal.
Discharge pressure pressure transducer as above
Power absorbed a power transducer is required unless a VSD is installed in which case this can be obtained from the VSD control panel
Flow rate - if no flow meter is already installed, PumpMonitor can derive the flow rate for each pump with reasonable accuracy after an initial calibration period during which a flow meter is installed temporarily. Note that this ability to derive flow may save the user major expenditure on a permanent flow meter, although on slurry pumps a flow meter would be recommended.
Bypass flow only certain pumps display this characteristic. It can be measured by an inexpensive electro-magnetic flow meter
Specific Gravity when pumping slurries, pulp, and viscous liquids with varying SG, the SG of the medium being pumped is required from a densometer. This is not required for water applications.
Speed if the pump is being driven by a variable speed drive the actual pump speed, output from the VSD, would be required.
Each pump to be monitored must be set up as follows:
Set up the pump register
TAS Online has a large library of standard pump curves for major pump manufacturers. If the pump curve does not exist in this library, or the pump OEM can supply a specific test curve, then TAS Online will input the standard curve data and add it to the library.
Set pump performance baseline. The current performance characteristics of the pump must be established accurately in order to calibrate PumpMonitor and to provide a baseline against which future measurements can be compared.
Undertake a full performance test on the pump using installed and / or portable instrumentation
Calculate the actual duty point at which the pump is operating (flow rate, head, power, efficiency and speed) and relate back to the standard pump curve
Feed all information back into the pump register to recalibrate the pump calculations, and thereby check the accuracy of flow and wear calculations.
Readings from all the instrumentation described above is uploaded to the TAS Online Remote Server (TRS) in a secure location (e.g. Control Room) on the site. It is then transmitted to the TAS Online Central Server (TCS) via GPRS, fixed line modem or Internet gateway.
Where a SCADA system is in place the instruments are connected to this system and the data extracted from the SCADA database by the TRS.
Where no SCADA exists data is transmitted from individual pumps via wireless links to the TRS.
DATA STORAGE AND REPORT DISTRIBUTION
Once the TAS PumpMonitor instrumentation and communications are in place and calibrated, then the system stores and processes the incoming data, and makes it available to the user as follows:
The TCS is Internet based and runs the full TAS PumpMonitor processing software. It is located in a protected environment and is able to receive multiple transmissions, whether by GPRS, fixed line modem or Internet gateway.
Raw performance data is filtered to check for significant variations and, if necessary an alarm can be raised via SMS or e-mail.
Further analysis of the data is performed and the results stored back on the TCS. The database thus contains both raw and processed information, available to the end user through a range of web-based reports.
Distribution of PumpMonitor information may be through various channels, as specified by the user:
Authorised personnel with Internet access will be able to log onto a password protected Internet website to view all pertinent pump performance and condition information.
The Internet access can be limited to the TAS PumpMonitor site only by the users IT personnel.
The user can place PumpMonitor reports on his own Intranet for access by authorised staff.
Email and SMS
Monthly or quarterly reports can be sent to nominated staff via email.
Deviations and occurrences can be emailed or sent via SMS to the responsible technician, foreman, engineer or manager within a short time. The duration of this delay is determined by the frequency at which the data is logged on the SCADA or other user database
PUMPMONITOR STANDARD REPORTING
The following reports are supplied under the standard TAS PumpMonitor licence agreement.
The Pump Register screen (see Fig.1) displays a listing of all the pumps currently being monitored to which this specific user has authorised access. These could be at locations all around anywhere in the World where appropriate communications are accessible.
From this screen the user can select a specific pump that he would want to view.
Fig.1: Listing of pumps currently being monitored
Once a specific pump has been selected, the user will have a view of the Pump Duty Register (see Fig.2). This displays detailed raw and calculated information (e.g. flow rate, head, power, pressure, density, speed, QBEP), recorded at the predefined interval nominated by the user.
The user can select to view this information for any specific period.
Fig.2: Current duties for the selected pump
The user can now specify the points to be plotted on the Real Time Duty Curve for the pump.
Real Time Duty Curve
PumpMonitor will plot actual duties superimposed on the standard performance curve for the selected pump (see Fig.3). The crosses and black cloud show where the pump is actually operating and the triangle shows the original duty point, where the pump was meant to operate.
From this example it can clearly be seen that the pump is running way off its BEP, which would result in various mechanical problems. In this case problems such as low-flow cavitation, suction recirculation and reduced impeller life are to be expected.
Fig.3: Plotting current pump duty on standard performance curve
Summary Technical Report
From the information provided a Summary Report can now be drawn (see Fig.4) which shows an quantifies any reduction in pump efficiency and resulting increase in operating costs over time.
TAS PumpMonitor is unique in the way that it calculates the total loss in efficiency and breaks this down into its three major components:
From this example it can be seen that, for the period monitored (432hrs), there was a total loss of 32.1% or 48.7kW. This translates to a yearly loss of over R60 000. It can also be seen that the wear loss is excessive, indicating that this pump should be refurbished. The duty loss is also high and this may warrant making changes to the system.
Fig.4: Total wastage for the period is displayed
THE TAS PUMPMONITOR PRO OPTION
As an additional service TAS Online offer their Pro Option, an advanced pump analysis and consultancy service which is mandatory for the first year of PumpMonitor operation and thereafter optional.
The following is an illustration of the reports which would be supplied under this option.
Original Duty on OEM Curve
The first pump curve (see Fig.5) shows the current operating conditions, in this case 200l/s at 19.3m head, and is a standard item issued by the OEM which, in this instance, is based on pumping water.
Fig. 5: Original Design Duty Standard Water Curve
It is clear in this example that the pump is running way off its BEP. The further away a pump runs from its BEP the more energy it loses to internal recirculation and turbulence, resulting in power wastage. It also results in various mechanical problems, depending on which side of BEP the pump is running. In this case, with the pump operating far to the left of its BEP, problems such as reduced impeller, bearing and seal life, low flow cavitation and suction recirculation can be expected.
Current Pump Performance on Slurry Curve
The curve shown below in Fig.6 is a PumpMonitor Pro Option report that again shows the current operating conditions. In addition the TAS PumpMonitor system has added the Preferred Operating Region, Allowable Operating Region, QBEP (% of BEP flow), Head Ratio, Efficiency Ratio and Tip Speed. The curves are slurry curves, not water curves as in the previous illustration, and the correct efficiency can be seen as 51.7%.
It is obvious from the report that the 14/12 pump is too large for this requirement. It was probably selected for a larger duty based on a future plant requirement that never materialised. The tip speed of 19.7 m/s. is important to note in this instance.
Fig. 6: Current Duty Corrected Slurry Curve
Replacement Pump Recommendation
Given the data extracted from the plant, as shown in the above examples, TAS Online Engineers make recommendations as to the most suitable pump to be used to run as close to BEP as possible in this application.
In this example (see Fig.7) a 12/10 pump has been recommended and has the following advantages:
Efficiency has increased from 51.7% to 57.68%
QBEP has increased from 52% to 72%, thus reducing negative mechanical and wear related problems
Power consumed has decreased from 125.2kW to 112.2kW
Tip speed has only increased from 19.17m/s to 20.45m/s even though the impeller speed has increased from 700rpm to 900rpm.
An analysis was also performed on a Warman 10/8 pump with these parameters. Results indicated that the 10/8 pump would match the required duty extremely well in theory, as the 10/8 pump would operate just to the right of its BEP with an efficiency of 71%. However, this is a mill circuit application, and slurry pump theory dictates that the pump should be selected to operate to the left of BEP and should never be selected to operate on or to the right of BEP.
Fig. 8: Performance of Smaller Pump Plotted on OEM and Slurry Curves