China 
Africa 
Explore chapters and articles related to this topic
Fluid machinery
Published in Amithirigala Widhanelage Jayawardena, Fluid Mechanics, Hydraulics, Hydrology and Water Resources for Civil Engineers, 2021
Amithirigala Widhanelage Jayawardena
A screw pump uses two or more intermeshing screws to increase the pressure of fluid, including solids and move them. The screws take in fluid from the inlet side and push it out from the outlet side while increasing its pressure. The pump system can be of single-screw type, two- screw type or three- screw type. Single-screw type, which is also known as the Archimedes screw, has limited capacity and is used mainly to move water and wastewater including sewage. In the two- screw type, the screws are not in contact with each other, thereby minimizing wear and tear and extending their life. In the three-screw type, the driving screw is in contact with the other two to create the pressure. The disadvantage of the three-screw type is that the narrow space between the screws does not allow solid material to be moved. Thus, they can only be used to move relatively clean liquids.
Pumps
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Screw pumps are positive displacement, axial-flow pumps that operate by trapping the liquid between rotating screw threads. A number of designs are available, generally divided into single rotor and multiple rotor, with multiple rotor units subdivided into timed and untimed categories for synchronizing the rotors.
Pumps
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
Screw pumps are best suited for handling high-viscosity liquids, fuels, and petroleum products. These pumps are used for capacities up to 300 m3/hr and pressures up to 175 atm at speeds of rotation up to 3000/min. The advantages of screw pumps are their high speed, compactness, and quiet operation. Pump capacity is practically independent of pressure, and efficiency is rather high (in the range of 0.75–0.80). The field of application of single-screw pumps is restricted by capacity up to 3.6–7.0 m3/hr and pressures up to 10–25 atm. Their cost and maintenance are similar to those of centrifugal pumps of low capacity operating under pressures up to 3–5 atm. Screw pumps are considerably more economical when their delivery pressures exceed 10 atm. Single screw pumps are employed in handling dirty and aggressive liquids, solutions, and high-viscosity polymer solutions.
Analysis of internal fluid motion in an Archimedes screw using computational fluid mechanics
Published in Journal of Hydraulic Research, 2021
Scott Christopher Simmons, William David Lubitz
Screws are geometrically defined by outer diameter (Do), inner diameter (Di), pitch (S), inclination angle (β), and number of blades (N) (Fig. 1). In a case study using Bayesian optimization techniques, it was found that the optimal ratio between inner diameter and outer diameter for the ASGs in the sample set was Di / Do ≈ 0.54 (Lisicki et al., 2016). Interestingly this is the same value theoretically determined by Rorres (2000) for the optimal design of an Archimedes screw pump. Note this theoretical optimum does not fully account for energy losses in operating screws, and in practice slightly lower ratios are often used, with Di / Do ≈ 0.50 being perhaps the most common.
Trends in hydraulic actuators and components in legged and tough robots: a review
Published in Advanced Robotics, 2018
Koichi Suzumori, Ahmad Athif Faudzi
Hydraulic pumps convert mechanical energy, such as the rotations of motors or engines, to fluid energy. Hydraulic pumps such as piston pump, vane pump, gear pump, screw pump, and reciprocal pumps are among the types of pumps used in conventional hydraulics [40]. Recent development is mainly focused on piston, vane and gear pumps where these types of pumps are suitable for robotics and mobile hydraulics application. Small and compact pump using piezohydraulic structure was presented by Valdovinos et al. [134]. They demonstrate a proof-of-principle compact (centimeter size) piezo hydraulic pump that can produce useful mechanical work driven at frequencies in the kilohertz range compared with other piezohydraulic pumps. Tokyo Tech. and KYB Co. Ltd have developed a miniature piston pump [39] to be used in a new power pack as shown in Figure 11. The design is possible for both stationary and mobile hydraulic tough robots.
Latest STEMI treatment: a focus on current and upcoming devices
Published in Expert Review of Medical Devices, 2018
Elisabetta Moscarella, Salvatore Brugaletta, Manel Sabaté
The Impella (AbioMed, Danvers, MA) is a continuous, nonpulsatile, axial flow Archimedes-screw pump that is placed into the LV in a retrograde fashion across the aortic valve and provides active support by expelling aspirated blood from the LV into the ascending aorta thereby restoring blood flow to the failing organs. Impella increases mean arterial pressure, reduces LV pressure and volume, and increases coronary blood flow. The Impella system comes in three different sizes 2.5 (maximum output 2.5 l/min), 3.7 (Impella CP, maximum output 3.7 l/min) and 5.0 (maximum output 5 l/min) where the smaller devices can be placed percutaneously via a 12- to 14-Fr sheath, while the 5.0 device needs a surgical vascular access to insert a 22Fr sheath.