Technical Report: Pumping Systems
Technical Report: Pumping Systems
Centrifugal pumps are the most common and popularly used types of pumps in transferring fluids. Centrifugal pump refers to a simple type of pump that revolves on an impeller to move fluid or water through a centrifugal force. Centrifugal pumps are very reliable when it comes to delivering liquid from one location to another in several industries, including municipal wastewater and water plants, agricultural sector, mining, petroleum, power generation plants, pharmaceutical and chemical sectors.
The centrifugal pumps are important because they have the capability and capacity to handle huge water or fluids quantities, and give high levels of flow, and can also adjust their flow rates within a bigger range. Centrifugal system is built for and are fit for fluids with reduced degree of viscous rate that can pour like light oil or water. For fluids with high viscosity like 20wt or 10wt at about 68 to 70 degrees F, more horsepower is needed for the centrifugal pumps to work effectively. For the liquids with high viscosity above 30wt, the positive-displacement pumps are preferable to reduce energy bill.
Positive Displacement Pumps
The PDP is a type of pump where some liquid quantity is captured and held inside the cavity. The liquid is then discharged. The fluid displacement is done by a special system constituting of piston, plunger, diaphragm, and more, depending on the pump type. Some equipment is built with an expanding cavity residing on the suction side or/and a minimizing the cavity residing at the discharge side of the pump. The water or liquid is absorbed inside through suction on the inlet side on the expansion of the cavity. The liquid is then discharged when the cavity decreases in size.
The most common type of positive displacement pump is the rotary pump type. In the rotary pump, the liquid is moved through the aid of a rotary. The rotary rotation motion displaces the liquid from the reservoirs to the discharging pipe. Examples of rotary pumps include sliding or flexible vane, screw pump, flexible impeller, internal gear, twisted helical roots, and circumferential pump, amongst others.
Pressure, Heads, and Flow Rates
In this section, the pressure valves are converted to the matching head values, a plot is then created for head against the flow rate curves for every output frequency setting:
Table 1: Pressure, head, and flow rate characteristics
FLOW RATE OUTPUT FREQUENCY
Gal US/min 40 Hz 50 Hz 60 Hz
Pressure(psi) Head (ft) Pressure(psi) Head (ft) Pressure(psi) Head (ft)
0 8.90 20.56 15.40 35.57 21.40 49.43
2 7.30 16.86 12.90 29.80 19.00 43.89
4 6.30 14.55 11.96 27.63 18.30 42.27
6 5.21 12.04 10.50 24.26 17.27 39.89
8 4.75 10.97 9.20 21.25 15.60 36.04
10 3.20 7.39 7.32 16.91 14.00 32.34
12 x x 5.60 12.94 13.10 30.26
14 x x x x 10.97 25.34
16 x x x x 6.50 15.02
Head (ft) = Pressure (psi) * 2.31
Chart 1: Output Frequency
How the head varies with the flow rate
Using the results obtained from the experiment of pressure, head and flow rate, I have plotted the graph’s output frequency data to make a comparison of 40hz head and pressure to 50hz and 60hz head and pressure results.
The first observation and the most obvious one is that the results are trending upwards for all the output frequencies. Secondly, the heads are at higher levels in comparison to pressures.
6Hz heads are at a higher level than any other, followed by 50Hx head. 50Hz pressure is the lowest output, followed by 60Hz pressure.
It can be concluded that the higher the pressure, then the higher the heads. This is observed by the fact that high-pressure frequencies are yielding higher outputs in the graph.