Series and Parallel Pumps

Series and Parallel Pumps

Summary and Introduction This experiment is conducted to determine the effect of flow rate of water in series and parallel configuration towards the pressure and flow-rate of water in each pipe. Pumps are devices used to increase the velocity of water flow-rate which at the same time increases the amount of water that can be obtained compared to its normal flow-rate without the aid of pumps. It transfers mechanical energy into fluid energy which produce liquid flow. The mechanical energy is supplied by the constant rotation of the blades inside the pump. Centrifugal pumps are widely used in many applications in our daily lives to transfer liquid especially in domestic uses, sewage, petroleum pumping and many more. It has the same operating concept as the “water wheel” used in ships before motor is used to move a ship. The reasons behind it are because it‟s cheap and conventional. Another reason is that it has a few moving parts and therefore are able to generate water flow with higher pressure and velocity. Centrifugal pumps cannot be used to transfer liquid that has high viscosity because the work done generated are not sufficient to transfer the liquid and it will wear off the blades. It can be concluded that the pressure of water flowing in series configuration has higher pressure compared to the pressure of water in parallel configuration. In series configuration, the flow rates of water are not divided into several pipes which will decrease the pressure of water in the pipe. Therefore, it can be said that water flowing in series configuration has higher efficiency in transporting water at a higher velocity thus allowing it to transport water to a higher level. As for parallel configuration, the flow rate of water is much higher than the flow rate of water in series configuration. Since it is efficient in transporting a larger amount of water compared to series configuration, it can be used in a situation where a large amount of water is needed. Therefore, it can be concluded that series configuration is effective in transporting water to a place which is in higher level than the source while parallel configuration is effective in transporting a large amount of water at a place which is at the same or lower level from the source.

Procedures P1 General start-up procedures 1. 2. 3. 4.

The circulation tank is with water up to at least the water covers the end of the pipe output. The V5 was made sure to be in partial open position. The power supply is switched on. The appropriate pump is selected and the valve positions are adjusted as the following.

Pump Operation Single Series Parallel

Running Pump Pump 1, P1 Both pumps, P1 & P2 Both pumps, P1 & P2

Open Valve 1&4 1&3 1, 2 & 4

Close Valve 2&3 2&4 3

5. The pump is turned on and slowly open V5 until maximum flowrate is achieved.

ORIENTATION

MINIMUM FLOWRATE (LPM)

Single Series Parallel

20 20 40

MAXIMUM FLOWRATE (LPM) 90 90 160

P2 General shut-down procedures 1. The pump is turned off. 2. The valve V5 was made sure to be turned off fully in closed position. 3. The main power supply is turned off.

P3 Experiment 1: Single Pump Operation Set up of equipment: Fully Closed Valve 2&3

Fully Opened Valve 1&4

Variable Parameter Valve 5

Pump ON Pump 1

Procedures: 1. 2. 3. 4.

The basic procedure written in P1 is followed. The settings are set up as on the „set up of equipment‟ above. Valve 5 is slowly opened till the flow-rate reaches 20 LPM. The pressure reading on the pressure indicator is observed. The flow-rate and pressure values are taken when stable condition is achieved. 5. The observation is repeated by increasing the flow-rate by 10 LPM until the flow-rate reaches 90 LPM.

P4 Experiment 2: Series Pump Operation Fully Closed Valve 2&4

Fully Opened Valve 1&3

Variable Parameter Valve 5

Pump ON Both Pumps

Procedures: 1. 2. 3. 4.

The basic procedure written in P1 is followed. The settings are set up as on the „set up of equipment‟ above. Valve 5 is slowly opened till the flowrate reaches 20 LPM. The pressure reading on the pressure indicator is observed. The flowrate and pressure values are taken when stable condition is achieved.

5. The observation is repeated by increasing the flowrate by 10 LPM until the flowrate reaches 90 LPM.

P5 Experiment 3: Parallel Pump Operation Fully Closed Valve 3

Fully Opened Valve 1, 2 & 4

Variable Parameter Valve 5

Pump ON Both Pumps

Procedures: 1. 2. 3. 4.

The basic procedure written in P1 is followed. The settings are set up as on the „set up of equipment‟ above. Valve 5 is slowly opened till the flowrate reaches 40 LPM. The pressure reading on the pressure indicator is observed. The flowrate and pressure values are taken when stable condition is achieved. 5. The observation is repeated by increasing the flowrate by 20 LPM until the flowrate reaches 180 LPM.

Results and Analysis Experiment 1: Rotameter (FL 1) LPM

Digital Pressure Gauge 1 (DPL 1) Bar

Digital Pressure Gauge 2 (DPL 2) Bar

Digital Pressure Gauge 1 (DPL 1)

20 30 40 50 60 70 80 90

1.04 1.04 1.03 1.03 1.02 1.01 1.01 0.99

3.06 3.00 2.94 2.88 2.81 2.73 2.63 2.51

1.06 1.05 1.05 1.04 1.04 1.03 1.03 1.01

Digital Pressure Gauge 2 (DPL 2) 3.12 3.10 3.04 2.98 2.90 2.82 2.72 2.60

Analog Pressure Gauge 1 (APL 1) 0.01 0 0 0 0 0 0 0

Analog Pressure Gauge 2 (APL 2) 2.15 2.01 2.00 1.90 1.80 1.80 1.60 1.50

Digital Pressure Difference, (Gauge 2 – Gauge 1)

Analog Pressure Difference, (Gauge 2 – Gauge 1)

2.06 2.05 1.99 1.94 1.86 1.79 1.69 1.59

2.14 2.01 2.00 1.90 1.80 1.80 1.60 1.50

Pressure Difference, (𝑘𝑔 𝑓)/〖𝑐𝑚〗^2

Graph of Pressure Difference (Gauge 2 Gauge 1) vs Flowrate 2.5 2 1.5 Digital Pressure Difference, (Gauge 2 – Gauge 1)

1

Analog Pressure Difference, (Gauge 2 – Gauge 1)

0.5 0 0

20

40

60 Flowrate, LPM

GRAPH 1

80

100

Experiment 2: Rotameter (FL 1) LPM

Digital Pressure Gauge 1 (DPL 1) Bar

Digital Pressure Gauge 3 (DPL 3) Bar

Digital Pressure Gauge 4 (DPL 4) Bar

Digital Pressure Gauge 1 (DPL 1)

Digital Pressure Gauge 3 (DPL 3)

Digital Pressure Gauge 4 (DPL 4)

Analog Pressure Gauge 1 (APL 1)

Analog Pressure Gauge 3 (APL 3)

Analog Pressure Gauge 4 (APL 4)

20 30 40 50 60 70 80 90

1.04 1.03 1.03 1.02 1.02 1.01 1.00 0.99

3.04 2.99 2.93 2.85 2.78 2.70 2.66 2.53

4.97 4.87 4.76 4.62 4.46 4.34 4.14 4.02

1.06 1.05 1.05 1.04 1.04 1.03 1.02 1.01

2.14 2.09 2.04 1.94 1.84 1.73 1.63 1.53

4.28 4.18 4.08 3.87 3.67 3.57 3.47 3.26

0 0 0 0 0 0 0 0

2.10 2.05 2.00 1.90 1.80 1.70 1.60 1.50

4.20 4.10 4.00 3.80 3.60 3.50 3.40 3.20

Digital Pressure Difference, (Gauge 4 – Gauge 1)

Digital Pressure Difference, (Gauge 3 – Gauge 1)

Analog Pressure Difference, (Gauge 4 – Gauge 1)

Analog Pressure Difference, (Gauge 3 – Gauge 1)

3.22 3.13 3.03 2.83 2.63 2.54 2.45 2.25

1.08 1.04 0.99 0.90 0.80 0.70 0.61 0.52

4.20 4.10 4.00 3.80 3.60 3.50 3.40 3.20

2.10 2.05 2.00 1.90 1.80 1.70 1.60 1.50

Pressure Difference, (𝑘𝑔 𝑓)/〖𝑐𝑚〗^2

Graph of Pressure Difference (Gauge 4 – Gauge 1) vs Flowrate 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0

Digital Pressure Difference, (Gauge 4 – Gauge 1) Analog Pressure Difference, (Gauge 4 – Gauge 1) 0

20

40

60

80

100

Flowrate, LPM

GRAPH 2

Pressure Difference, (𝑘𝑔 𝑓)/〖𝑐𝑚〗^2

Graph of Pressure Difference (Gauge 3 – Gauge 1) vs Flowrate 2.5 2 1.5 1

Digital Pressure Difference, (Gauge 3 – Gauge 1)

0.5

Analog Pressure Difference, (Gauge 3 – Gauge 1)

0 0

20

40

60

80

Flowrate, LPM

GRAPH 3

100

Experiment 3: Rotameter (FL 1) LPM

Digital Pressure Gauge 1 (DPL 1) Bar

Digital Pressure Gauge 2 (DPL 3) Bar

Digital Pressure Gauge 4 (DPL 4) Bar

Digital Pressure Gauge 1 (DPL 1)

Digital Pressure Gauge 2 (DPL 3)

Digital Pressure Gauge 4 (DPL 4)

Analog Pressure Gauge 1 (APL 1)

Analog Pressure Gauge 2 (APL 3)

Analog Pressure Gauge 4 (APL 4)

40 60 80 100 120 140 160 180

1.03 1.03 1.02 1.02 1.02 1.00 0.99 0.98

3.03 2.98 2.92 2.86 2.78 2.70 2.62 2.50

2.99 2.93 2.88 2.82 2.74 2.66 2.56 2.59

1.05 1.03 1.04 1.04 1.04 1.02 1.01 1.00

3.08 3.04 2.98 2.92 2.83 2.75 2.67 2.55

3.05 3.00 2.94 2.78 2.16 2.11 1.80 2.51

0 0 0 0 0 0 0 0

2.15 2.00 1.90 1.85 1.82 1.79 1.63 1.58

2.10 2.00 2.00 1.90 1.84 1.80 1.65 1.60

Digital Pressure Difference, (Gauge 4 – Gauge 1)

Digital Pressure Difference, (Gauge 3 – Gauge 1)

Analog Pressure Difference, (Gauge 4 – Gauge 1)

Analog Pressure Difference, (Gauge 3 – Gauge 1)

2.00 1.97 1.90 1.74 1.12 1.09 0.79

2.03 2.01 1.94 1.88 1.79 1.73 0.93

2.15 2.00 1.90 1.85 1.82 1.79 1.63

2.10 2.00 2.00 1.90 1.84 1.80 1.65

2.5

Graph of Pressure Difference (Gauge 4 – Gauge 1) vs Flowrate

2

1.5

Digital Pressure Difference (Gauge 4- Gauge 1) Analog Pressure Difference (Gauge 4- Gauge 1)

1

0.5

0 50

100

150

200

GRAPH 4

2.05 2 1.95

Graph of Pressure Difference (Gauge 3 – Gauge 1) vs Flowrate

1.9 Digital Pressure Difference, (Gauge 3 – Gauge 1) (kg f)/〖 cm〗^2

1.85 1.8

Analog Pressure Difference, (Gauge 3 – Gauge 1) (kg f)/〖 cm〗^2

1.75 1.7 1.65 1.6 1.55 50

100

150

200

GRAPH 5

Analysis: 1. For experiment 1, 2 and 3 the readings on pressure gauge 1 is made to be deducted by the readings of other pressure gauges because it is the inlet pipe of the water. 2. The reading of the digital pressure gauge is initially in the unit of bar therefore it has to be converted to

to make all the units same.

Sample Calculations: 1. Conversion from bar to 1 bar = 1.04 bar ×

= 1.06

Discussion Based on all the analog readings of pressure gauge 1 of all experiments, the reading is 0. By comparing the analog pressure gauge reading and the digital pressure gauge reading, the difference in pressure is not really too far from each other. But then the digital reading of pressure may be more accurate because the average value of the data was taken. As for analog pressure reading, there may be errors while taking the reading of the pressure because the pin was fluctuating. Both readings may have errors due to the unstable flow of the water and the air bubbles found in the water will further increase the percentage error. It is suggested that different pipe diameters should be used to accommodate to the unstable flow to get a stable reading. By analyzing graph 1, 2 and 3 they have more stable flow compared to graph 4 and 5 which was plotted by using the data from experiment 3. Other factors that could contribute to the errors are impeller diameter, clearance and blade design. Overall, the head generated (by using the calculated), by any centrifugal pump decreases as the flow rate provided by the pump increases.

Conslusion

The experiment is successful. The graphs in experiment 1 and 2 and 3 show a positive result. It is also proven that series pump operation has higher velocity compared to of parallel pump operation by having a higher pressure difference. As to prove that parallel pump operation can transfer larger amount of water compared to series pump operation, the rotameter reading can be referred. The maximum amount of water that can be transferred by series pump operation is 90 LPM while the maximum amount water that can be transferred by parallel pump operation is 160 LPM.

References 1. How Centrifugal Pumps Work: Advantages and Disadvantages of Centrifugal Pumps; http://www.pumpsolutions.com.au/how-centrifugal-pumps-work-advantages-and-disadvantagesof-centrifugal-pumps/

2. Centrifugal Pump; March 2009; http://en.wikipedia.org/wiki/Centrifugal_pump