LAB 1 Pump Station Design

 

System Setup
Procedure
Setting up the equipment
Develop the Pump Curve
Vary Pump Speed
Pumps in Parallel
Pumps in Series
Pressure Regulation using PRV
Pressure Regulation Using VFD

Introduction

Safety Considerations

  • Closed-toed shoes are required in the Hydrotechnical Lab
  • Safety glasses are required in the Hydrotechnical Lab
  • Incorrect use of the apparatus may cause water hammer which has 
the potential to burst the pipes – this has recently occurred with this apparatus so please be careful to turn on valves (rotate red handles)  slowly.

Link to Lab 1 Manual   Here – CIVL315_Lab 1_ Manual_Aug2018_Final


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System Setup

Experimental Configuration

The apparatus consists of:

  • Control Panel (gray)
  • Two Ultrasonic Flow Meters
  • Pressure Regulator Valve (PRV)
    • Pressure regulator valves reduce the downstream pressure to a constant value depending on the mechanical adjustment.  As the flow passes through the valve constriction, there is a frictional dissipation of the energy that results in a pressure drop.
  • Reservoir
  • Variable Frequency Drive (VFD)
    • A variable frequency drive is a device that receives a constant frequency electrical AC supply and outputs an AC current at a specified frequency.  By applying this output to an AC motor, the speed of the motor can be precisely controlled.
  • Three Pressure Monitoring Ports (with both mechanical gauges and digital readouts)
  • A Pump with a variable frequency drive: referred to as “Pump 1” or “P1”
  • A Pump with a fixed speed drive: referred to as “Pump 2” or “P2”
  • Piping with various manually operated valves (red handles).
  • Distribution Valve assembly


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Procedure – Special Operating Notes

  • Opening/Closing Valves: Incorrect use of the apparatus may cause water hammer which has the potential to burst the pipes.  Always open and close the valves slowly to prevent pressure spikes. For the large valves, this will require using both hands (one on each side of the valve handle) to turn the valve handle. Follow directional arrows on valves “S”= shut and “O”= open
  • In case of pump 1 lockdown  (overload – indicated by “oL” on VFD)  try turning the control panel off , wait 10 seconds and then turn on again. If that does not work, please consult with the TA.
  • If an acoustic flow meter has an “E #”on the display that indicates a condition such as no flow and/or turbulence near the sensors.  This will sometimes happens during testing and will typically clear itself when there is a proper flow to measure in the pipe.  If you think there should be a proper flow and the flow meter still displays an “E #” condition, consult a technician.
  • When measuring the AC current used by the VFD , a correction factor needs to be applied to get the actual (true) current.  Please use the table below to apply the correction.
Pump 1

Current Meter

Reading (A)

Actual VFD

Current

Draw (A)

0.12

0.34

0.80

1.73

2.26

2.92

3.30

3.68

4.07

4.61

5.57

6.74

7.99

8.33

0

0.42

1.22

2.47

3.13

3.92

4.30

4.67

5.02

5.56

6.56

7.73

8.95

9.31

 

NOTE:  Lab procedures can take a long time if students are not prepared.  It is strongly recommended that you familiarize yourselves with the procedures before coming to your lab session.  In particular, you should create a blank data table in Excel for the data you will be collecting.  The data table should include a column for each measurement type (current, pressure, flow rate, etc..) and a row for each flow configuration (which distribution valves are open, pump configuration, PRV, etc….). This will help you to organize and streamline your measurements.  


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Setting up the equipment

  1. Turn on the power to the two flow meters using the switch located near them.
  2. Check that the reservoir is more than half full of water. Use the water supply on the north wall to fill the reservoir if needed. Make sure that the hose is wound back on the reel after use.
  3. Check that the pump power switches are OFF and then turn on the control panel power.
  4. Check that both pump output valves located directly above pump 1 and pump 2 are closed.
  5. Check that the pumps are configured in parallel.

This video demonstrates the steps needed to develop the pump curve, as well as the steps to properly control pump 1. Follow the valve opening and closing procedures precisely to avoid water hammer.
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Video 1 – (covers Develop the Pump Curve steps 1-6 & Vary Pump Speed Steps 1-3)

 

Develop the Pump Curve

  1. Check that the bypass valve is closed as well as the valve leading to the pressure-reducing valve. The distribution valves should also be closed.
  2. Configure pump valves to operate with pump 2 only.
  3. Open the Pump 2 output valve slowly to avoid water hammer.
  4. Open the bypass valve.
  5. Vary flow rate by incrementally open distribution valves 1 – 6 and record the flow rate using the ultrasound flow meters.
  6. After collecting all the data, close all distribution valves. Close the Pump 2 output valve. Turn off Pump 2 by turning the power switch on the control panel.


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Vary Pump Speed

  1. Configure pump valves to operate with pump 1 only.
  2. Ensure the output valve from the variable speed pump is closed and start pump at 0 rpm. Then set speed to 3450 rpm.
  3. Open the pump 1 output valve slowly.
  4. Open the bypass valve.
  5. Set pump 1 speeds 3450, 3200, 2900, 2500, 2000 and 1600 rpm.
  6. Vary flow rate by incrementally opening distribution valves:
    1. 0-6 for 3450 rpm
    2. 0-4 for all other speeds
  7. After recording the data, close all distribution valves. Close Pump 1 outlet valve. Set pump 1 rpm to zero and turn off power to pump 1.


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Pumps in Parallel

  1. Configure pump valves to operate both pump 1 and 2 in parallel. Turn on Pump 1 first (speed 3450) and then open outlet valve slowly.  Finally turn on pump 2 and open it’s outlet valve.
  2. Bypass the pressure-reducing valve.
  3. Set pump 1 speeds to 3450, 3200, 2900, 2500, 2000 and
    1600 rpm.
  4. Vary flow rate by opening 1 to 3 distribution valves.
  5. Close all distribution valves. Close pump 2 output valve.
  6. Close pump 2 output valve. Sets pump 1 rpm to zero. Then shutdown pump 1 and 2 power with control panel switches.


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Pumps in Series

  • Configure pump valves to operate both pump 1 and 2 in series.
  • Bypass the pressure-reducing valve.
  • Set pump 1 speeds to 3450 and 2900 rpm.
  • Vary flow rate by incrementally opening distribution valves
    1. 1-3 for 3450 rpm.
    2. 1-2 for 2900 rpm.
  • Close distribution valves. Close bypass valve. Close pump 2 outlet valve then close pump 1 outlet valve.
  • Set pump 1 rpm to zero, then shutdown pump 1 and 2 power with the control panel switches.

The following video shows how to regulate pressure by using the pressure reducing valve and the variable frequency drive.
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Video 2

 

Pressure Regulation using PRV

  1. Configure pump valves to operate both pump 1 and 2 in parallel and make sure both pump outlet valves closed.
  2. Set pump 1 to maximum speed then turn on pump 2.  Open pump 1 outlet valve first then pump 2 outlet valve.
  3. Enable pressure-reducing valve (close bypass).
    1. Regulate distribution pressure (Gauge 3) to 4.5-5.0 psi using the labelled adjustment bolt.
  4. Vary flow rate by incrementally opening distribution valves (1-6).
  5. Close all distribution valves and turn off pump 2 (leave pump 1 running).

 

Pressure Regulation using VFD

  1. Bypass the pressure-reducing valve.
  2. Vary flow rate by incrementally opening distribution valves (1-6).
  3. Regulate distribution pressure (Gauge 3) to 5.0 psi by controlling the speed of pump 1.Measure the current and voltage drawn by the pump after the distribution valve is open.
  4. Repeat until all distribution valves are open. When distribution valves 5 and 6 are open, pump 1 alone is not powerful enough to reach the desired pressure. Turn on pump 2 in parallel with pump 1 and reduce the rpm of pump 1 to achieve desired pressure (5.0 psi).

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