ChE Laboratory II:
Series and Parallel Pump Submitted by: De La Cruz, Roel Ian M. Fulugan, Ceazar Justine L. Madriñal, Andrea Coleen E. Sim, Tristan James G.
BS ChE V A.Y. 2017-2018
Submitted to: Engr. Milagros R. Cabangon
INTRODUCTION................................................. ....................................................................................................... .............................................................................. ........................ 2 PARTS AND FUNCTIONS ................................................................................................................ 6 EXPERIMENT .......................................................................................................... .................................................... ............................................................................ ...................... 10 PUMPS IN SERIES AND PARALLEL .................................................. .......................................................................................... ........................................ 10 OBJECTIVES .......................................................................................................................... ......................................................................... ................................................. 10 PROCEDURE .................................................................................................................... ................................................................ ......................................................... ..... 10 THEORIES ...................................................................................................... ................................................ ..................................................................................... ............................... 15 Two Pumps in Series............................................. Series.................................................................................................. ................................................................... .............. 16 Two Pumps in Parallel ............................................................................................................. 17 Pump Efficiency ..................................................... .......................................................................................................... ................................................................... .............. 20 LATEST EQUIPMENT .................................................. ....................................................................................................... ................................................................... .............. 20 Specifications ........................................................................................................................... ................................................................................... ........................................ 21 EXERCISES AND PRACTICAL POSSIBILITIES ..................................................... ........................................................................... ...................... 22
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
Pumps are used to transfer fluid in a system. The transfer can either be at the same level or to a new height.
is the relationship between the “head” and the
flow rate. The flow rate depends on the height to which the fluid is pumped. Experimentally, we can use characteristic for a pump. The
to determine the pump provides
a low cost and effective way of demonstrating how the determination is achieved, and enabling more detailed experiments to be done. The H32 uses “circulators”, or most commonly known as central heating pumps, which provide relatively low outputs compared with pumps designed for high performance. Thus, H1 Hydraulic Bench can be used as the source of water and at the same time to measure the flow rate. In real life engineering applications, a single pump can sometimes not deliver the flow rate or head necessary for a particular requirement, but using two or more can be combined in series to increase the flow rate. H32 can demonstrate how the combined pump
characteristic compares with that of the single pump. More sophisticated pump test sets CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
may be found in the TeQuipment range, such as the H36 Computerized Centrifugal Pump Test Rig, which are suitable for more advanced studies in the fluid dynamic performance of pumps. The TeQuipment H32 Series and Parallel Pump Test Set is one of a range of small equipment intended for use with TeQuipment H1 Gravimetric Hydraulic Bench or H1d Volumetric Hydraulic Bench. Two single phase multi – speed pump units are connected by a pipe system so that each pump can run on its own, or combined in series or in parallel. The figures below show the position of the three valves used to control each flow condition. Each pump has a control panel which switches it on or off.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
One Bourdon gauge is fitted to the top panel which can be switched to measure the delivery pressure of both pumps. The pump inlet pressure can be determined from Bernoulli’s Equation. The water flow rate can be adjusted using a gate valve in the return pipe between the pump test set and the hydraulic bench. This valve should not be fitted in the water pipe leading to the pump test set to avoid unknown and variable pressure drop. If a valve is fitted before a pump, the valve should be fully opened during measurements. The input powers quoted by the pump manufacturer will be sufficient to demonstrate how the efficiency is calculated. The table below gives the typical input power with corresponding pump speeds.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
40
750
70
1150
105
1850
It reads the delivered pressure by the pump during the operation.
They switch on if the pressure reading on pump 1 or pump 2 is necessary.
It powers on and off the device.
It regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
passageways.
It is the entry point of fluid into the pump area.
It is used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
It is the exit point of the pumped fluid.
Operating Environment: Laboratory environment
Storage Temperature Range: - 25oC to 55oC (when packed for transport)
Operating Temperature Range: 5oC to 40oC
Operating Relative Humidity Range: 80% at temperatures <31oC decreasing linearly to 50% at 40oC
Net dimensions: 520 mm x 460 mm x 700 mm
Packed dimensions and weight: 0.34 m3 and 25 kg
Volumetric Hydraulic Bench (H1D)
Electrical Supply: 230 VAC, 50/60 Hz, 2A, single-phase or two-phase
Water Supply: From the Hydraulic Bench (H1D)
Floor space needed: 1m x 1m (plus space for the hydraulic bench)
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
1 Delivery Pressure 2 Pump Button 3 Power Switch 4 Centrifugal Pump 5 Inlet 6 Valves 7 Outlet
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
•
To develop pump characteristic curves for a single pump, two pumps in series, and
two pumps in parallel by measuring head (h) and flow rate (Q) using the experimental apparatus. •
To develop theoretical pump characteristic curves for pumps in series and pumps in
parallel experimentally derived single pump characteristic curve. •
To compare the experimental and theoretical pump characteristic curves for pumps
in series and parallel.
1.
Set the valves for a particular pump test.
2.
Set the required pump speed(s).
3.
Switch on the unit by depressing the green button on the console.
4.
Set up the delivery flow rate by adjustment of the gate valve on the outlet side of the
pumps. It is convenient to start with a fully open valve. Measure the flow rate using the Hydraulic Bench. 5.
Read the delivery pressure of each pump by switching to either p1 or p2. Ensure the
valve is switched off after each measurement. 6.
Enter the results in the table.
7.
Repeat for several different flow rates until the control valve is fully closed.
8.
Measure the difference in height between the water surface in the reservoir and the
pump inlet. Calculate the inlet pressure. CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
9.
Calculate the pressure rise across the pump.
10.
Plot a graph of pressure rise against flow rate.
11.
If required, calculate and plot the overall efficiency of the pump system.
FLOW RATE
DELIVERY PRESSURE
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
INLET PRESSURE
PRESSURE RISE
FLOW RATE
DELIVERY PRESSURE
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
INLET PRESSURE
PRESSURE RISE
FLOW RATE
DELIVERY PRESSURE
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
INLET PRESSURE
PRESSURE RISE
FLOW RATE
DELIVERY PRESSURE
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
INLET PRESSURE
PRESSURE RISE
The increase in head H between the inlet and outlet of a pump is a function of the flow rate Q and rotational speed N. This relationship is expressed graphically and called the
“pump characteristic”, as shown in Figure 1.
Head is a height measured in meters of water. It is denoted by H. In cases, the pressure rise across the pump, Δp (N/m2 or bar) can be used as an alternative convention to head. Δp and Head are related to each other by the equation ∆ = . In terms of Head, the mass flow rate through the pump is = , in kg/s. The hydraulic power generated is = = , in Watts. The electrical power input to pump is W. The overall pump efficiency is =
=
.
In terms of pressure rise across the pump, the overall pump efficiency is =
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
∆
.
The overall pump efficiency of a small circulating pump is typically not much greater than 10 to 15%.
TeQuipment, the manufacturer of H32, published performance curves shown in Figure 2. For practical convenience, pressure is measured in kN/m 2 and flow rate in Liters/s, but on experimental equipment the pressure is measured in bars, where 1 bar = 100 kN/m2. If you are using a gravimetric hydraulic bench, approximately for water, then 1 liter/s = 10,000 m3 /s ≈ 1kg/s. The input power W, may be measured using a wattmeter, or you may use the manufacturer’s published data.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
Shown in Figure 3, the schematic diagram of two pumps connected in series. Ignoring any losses that occur between the two pumps, the flowrate through is the same but the overall pressure rise is the sum of the pressure rise in both pump. Figure 4 shows the pressure – flow characteristics for pumps connected in series.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
Figure 5 shows the schematic representation of pumps connected in parallel orientation. The pressure rise in each pump is the same and is also equal to the total pressure rise. The overall flowrate however, is the sum of the flowrate in each pump. Figure 6 show the pressure – flow characteristics of the pumps connected in parallel.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
The equation for the actual pressure – flow characteristics is ∆ = − 2, where A and B are constants which depend on the system. It is therefore useful to plot curves of Δp against Q2, which should be straight lines.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
Pump efficiency is calculated from the equation:
=
∆
Where Q is the flow through each pump and ∆ is the pressure rise across it Care should be taken when calculating the individual efficiency of pumps in series and parallel. In series, the flow through each pump is equal to the measured flow, but the pressure rise across the upstream pump is approximately (p1 – p2). In parallel flow the flowrate through each pump is half the measured value.
The Edibon Series and Parallel Pump Set Test is designed to demonstrate the operational advantages of pumps connected in series or parallel operation, depending on the required duty. The unit consists of two centrifugal pumps, a water feed tank, circulation pipes, regulation valves, three pressure sensors and a flow sensor.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
The centrifugal pumps can operate: (1) alone; (2) coupled in series; or (3) in parallel. A three – phase motor activates a pump with possibility of adjustment and measurement of the turn speed as well as the transmitted mechanic torque, and a single-phase motor activates the other pump. The pumps are installed in a pipes system, which, as it is a closed circuit, avoids the permanent waste of water during the operation. By the appropriate positioning of the valves it is possible to connect the pumps individually, in series or in parallel, depending on which test is going to be performed.
Anodized aluminum structure and panels painted steel
Main metallic elements in stainless steel
2 Centrifugal pumps o
Maximum flow: 120 L/min
o
Maximum height (approx.): 25 mwc (meter of water column)
o
A three-phase motor activates a pump, 0.37 kW with continuous speed adjustment with inverter of frequency/voltage; and other single-phase motor activates the other pump.
3 Valves that allow connecting the pumps separately, in series or in parallel, by the appropriate positioning of the valves and 2 regulating valves.
Torque measurement and speed measurement.
Discharge pressure sensor (0 to 2.5 bar).
Admission pressure sensor (-1 to 0 bar).
Flow sensor (0-150 L/min).
: 220 V/50 Hz
: 1530 x 700 x 800 mm : 105 kg
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
1. Obtaining curves H(Q), N (Q), Eff % (Q). 2. Three simultaneous representations of H(Q), N (Q), Eff % (Q). 3. A dimensional study of magnitudes H*, N* and Q*. 4. Cavitation test and obtaining curves NPSH. 5. Series coupling of two pumps with same characteristics. 6. Series coupling of two pumps of different characteristics. 7. Parallel coupling of two pumps with same characteristics. 8. Parallel coupling of two pumps of different characteristics. 9. Sensors calibration 10. Open Control, Multicontrol and Real Time Control.
CHE LABORATORY II: DE LA CRUZ, FULUGAN, MADRIÑAL, SIM
