Case Study - Eastbury Water Pumping Station, Affinity Water, UK.

 

The test parameters of head, power and efficiency are compared with those of the as-new pumps:

 

Pump No.

Head

Power

Efficiency

43

-1%

2%

0%

44

-2%

0%

-2%

47

-5%

+4%

-9%

48

-9%

+5%

-14%

59

-8%

+8%

-16%

60

-2%

+4%

-6%

 

Sensors

 

Pumping Station Eastbury Pumping Station has 6 pump sets which pump ground water, supplied to an on-site tank by local borehole pumps, on to the inlet tank at the treatment works.

 

Pumps 43 & 44 are fixed speed Flowserve units rated at 1000 m3/hr at 115m and 1480rpm, Pump 47 is a variable speed Weir unit rated at 19ML/d at 116m and 1479rpm, Pump 48 is a variable speed Weir unit rated at 24ML/d at 116m and 1475rpm, Pumps 59 & 60 are variable speed KSB units rated at 162l/s at 127m and 1488 rpm.

 

 

Thermancy HMI Fitted in the Pumproom

 

 

 

Comment on Test Results

 

Pump 43:

No shortfall of efficiency. Pump in good condition. This pump impeller was trimmed by the manufacturer after the factory test which may have caused the differences in the head/flow and power/flow profiles

Pump 44:

Small shortfall of efficiency. Pump in good condition

Pump 47:

Medium shortfall of efficiency, mostly due to corrosion of hydraulic surfaces. Different curve profiles may have been caused by previous refurbishment work

Pump 48:

Medium/High shortfall in efficiency, mostly due to corrosion of hydraulic surfaces. A priority unit for refurbishment/replacement. Again, different curve profiles may have been caused by previous refurbishment work

Pump 59:

Medium/High shortfall in efficiency, mostly due to corrosion of hydraulic surfaces. Low as-new efficiency, so replacement with a higher efficiency pump is recommended in preference to refurbishment

Pump 60:

Low/Medium shortfall of efficiency. Requires overhaul to sort out noisy operation and leakages

 

Pump Scheduling

 

The kW per m3/hr specific powers for the pumps and pump combinations of the existing schedule are calculated in the table below:

PLCMode

Flow rage

m3/hr

Average

kW/(m3/hr)

Existing

Pump

Schedule

Proposed

Pump

 Schedule

Power

Saving %

0

0-550

-

-

47

15.5

1

550-750

0.451

59/60

47

9.1

2

675-1100

0.382

47

48

5.8

3

875-1275

0.402

48

47+43

0.1

4

1150-1950

0.402

59/60+43/44

48+43

2.9

6

1700-2100

0.377

47+43/44

47+48+43

6.6

7

1850-2200

0.386

48+43/44

47+48+43

4.3

8

2050-2450

0.412

59/60+47+43/44

47+48+43

2.3

9

2250-2700

0.424

59/60+48+43/44

 

1.7

Further Savings

The above flow schedules match the flow ranges programmed in to the pumping station PLC system. Larger savings can be achieved by adjusting the scheduled flow ranges to better match the flow rates of the highest efficiency pumps.

 

System Curve Pump Performance Test