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Traditional systems of drinking water delivery
Published in Thomas Bolognesi, Francisco Silva Pinto, Megan Farrelly, Routledge Handbook of Urban Water Governance, 2023
Raziyeh Farmani, Chris Sweetapple
Different types of pumps are available, with centrifugal pumps being the most commonly used in water distribution systems. These are easy to install and operate, are low cost, and can be operated under a variety of conditions. Specific types of centrifugal pump include axial-flow, radial-flow, and mixed-flow. Radial-flow pumps provide (relatively) low capacity and high head, and, in water distribution systems, they may be used where there is an elevation difference between supply and distribution areas, to enable water to be transferred from low elevation to high elevation during low energy tariff times and used during peak demand time. Axial-flow pumps, conversely, provide high capacity but low head, and they can be used where there is relatively little difference in elevation – for example, transferring raw water from a reservoir to a treatment plant. Mixed-flow pumps deliver a moderate flow of water with medium head.
Overview of the Fermentation Industry
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
A pump is a device that moves fluids (liquid or gas), sometimes slurries, by mechanical action. It is used for domestic, commercial, industrial, agricultural service, municipal water and wastewater services. Pumps can be classified into two major types according to the principles by which the energy is added to the fluid; one is the positive displacement pump and the other is the non-positive displacement pump (Figure 6.8).
Design of Pump and Meat Systems
Published in Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen, Design of Remediation Systems, 2020
Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen
This is illustrated graphically in Figure 7.4. It is essential that the NPSHA be greater than NPSHR with a factor of safety of approximately 2 to 3 ft. When the NPSHR is equal to or greater than the NPSHA, cavitation can occur. Cavitation refers to the formation of gas bubbles (vaporization) at points of low pressure, such as at the pump inlet, and their eventual collapse under high pressure. From Bernoulli’s tboreom, when velocity incrouxeu, such as at the impeller, there is a decrease in pressure. Under reduced pressure conditions (or similarly, at elevated temperatures), the waters’ tendency toward vaporization increases.
TS Fuzzy Fault-Tolerant Tracking Control of a PV Pumping System Based on an Induction Motor
Published in IETE Journal of Research, 2021
Zeineb Ben Safia, Maher Kharrat, Moez Allouche, Mohamed Chaabane
Different configurations have been developed for optimal control of PV pumping system in which sundry kinds of motors and pumps are used. According to the required application, the pumping system can be based on, submersible and surface or floating pumps types, and on Direct Current Motor or Induction Motors. Starting with pumps, the most commonly employed pump type is the centrifugal pump. This one, transfer energy to the liquid by a centrifugal force produced by the rotating impeller. It is broadly used because of its design simplicity, high efficiency, smooth flow rate and ease of operating [1]. In the literature, various types of motor have been used for the PV pumping systems, to drive the pump. The choice is made depending on the reliability and the price. DC motors are used in pumping because they are easy to operate [2]. They were used for speed controls because of their simple design in controlling flux and torque [3]; but they require brushes and commutator maintenance [4]. To overcome this latter issue, Brushless DC motors have been suggested due to their simple control requirement and their high reliability [5]. However, AC motors and particularly Induction Motors (IM) are the most used actuators in the industry, and have been introduced in many applications [6]. These machines are characterized by their ruggedness and their high performance; among their most important features, low cost and no need for maintenance.
Temporary and Permanent Viscosity Loss Correlated to Hydraulic System Performance
Published in Tribology Transactions, 2018
Paul Michael, Mercy Cheekolu, Pawan Panwar, Mark Devlin, Rob Davidson, Duval Johnson, Ashlie Martini
The effects of flow losses on the power requirements of the system were examined. The input power of the system was determined from pump torque and rotational frequency measurements. The output power of the system was determined from the motor torque and rotational frequency measurements. System power loss was determined from the difference between the output power of the motor and the input power of the pump. As shown in Fig. 14, the system required approximately 15% less input power at a fluid temperature of 50°C. Less power was required because the leakage flow at 50°C was lower. In a variable displacement pump, the compensator comes “off-stroke” when the flow demand of the hydraulic system is reduced. The resulting reduction in pump displacement decreased the input torque requirement of the pump because torque is a product of displacement and outlet pressure. Because system power outputs were similar for 50 and 80°C, reducing the input power to the pump yielded a net decrease in system losses. Pump efficiency (overall) is the ratio of pump output power to input power. Pump overall efficiency was relatively insensitive to the effects of fluid temperature on leakage flows. The fact that pump efficiency exhibited a negligible change when the input power shifted exemplifies one of the key performance benefits of variable displacement pumps. It also illustrates why “losses” tend to be a better indicator of the effects of fluid on system performance than efficiency.
Techno-economic analysis of a modified concentrating photovoltaic/organic Rankine cycle system
Published in International Journal of Ambient Energy, 2022
Rahim Moltames, Ramin Roshandel
In most ORCs, the pump is used to control the mass flow rate of the fluid. It should be noticed that the PV panel temperature largely depends on the refrigerant’s mass flow rate; hence, changing the R245fa mass flow rate leads to control the PV panel temperature, aiming to increase further the total efficiency of the integrated system. An inverter is used to control the rotational speed of the electric motor in the pump. In positive displacement pumps, the fluid flow rate is directly related to the motor’s speed, while in the centrifugal pumps, the mass flow rate of the fluid also depends on the head or pressure of the pump (Quoilin et al. 2013).