Crop protection equipment � Reciprocating positive displacement pumps and centrifugal pumps � Test method

2020 ◽  
Keyword(s):  
Crop Protection ◽  
Test Method ◽  
Centrifugal Pumps ◽  
Positive Displacement

Hemolysis generation from a novel, linear positive displacement blood pump for cardiopulmonary bypass on a six kilogram piglet: a preliminary report

Perfusion ◽  
2016 ◽  
Vol 32 (4) ◽  
pp. 264-268
Author(s):  
D. Scott Lawson ◽  
Derek Eilers ◽  
Suzanne Osorio Lujan ◽  
Maria Bortot ◽  
James Jaggers
Keyword(s):  
Cardiopulmonary Bypass ◽  
Surface Area ◽  
Preliminary Report ◽  
Blood Pump ◽  
Centrifugal Pumps ◽  
Clinical Value ◽  
Pump Design ◽  
Positive Displacement ◽  
Blood Pumps ◽  
Extracorporeal Circuits

Background: Current blood pumps used for cardiopulmonary bypass generally fall into two different pump design categories; non-occlusive centrifugal pumps and occlusive, positive-displacement roller pumps. The amount of foreign surface area of extracorporeal circuits correlates with post-operative morbidity due to systemic inflammation, leading to a push for technology that reduces the amount of foreign surfaces. Current roller pumps are bulky and the tubing forms an arc in the pumping chamber (raceway), positioning the inlet 360 degrees from the outlet, making it very difficult to place the pump closer to the patient and to efficiently reduce tubing length. These challenges put existing roller pumps at a disadvantage for use in a compact cardiopulmonary bypass circuit. Centrifugal blood pumps are easier to incorporate into miniature circuit designs. However, the prime volumes of current centrifugal pump designs are large, especially for pediatric extracorporeal circuits where the prime volumes are too great to be of clinical value. Method: We describe a preliminary report on a novel, occlusive, linear, single-helix, positive-displacement blood pump which allows for decreased prime volume and surface area of the extracorporeal circuit. This new experimental pump design was used to perfuse a 6 kilogram piglet with a pediatric cardiopulmonary bypass circuit for two hours of continuous use. Blood samples were obtained every thirty minutes and assayed for plasma free hemolysis generation. Conclusions: The results from this initial experiment showed low plasma free hemoglobin generation and encourages the authors to further develop this concept.

Aircraft Gas Turbine Engine Fuel Pumping Systems in the 21st Century

1997 ◽  
Vol 119 (3) ◽  
pp. 591-597 ◽  
Author(s):  
L. D. Hansen ◽  
G. D. Kucera ◽  
J. S. Clemons ◽  
J. Lee
Keyword(s):  
Gas Turbine ◽  
21St Century ◽  
Turbine Engines ◽  
Engine Fuel ◽  
Centrifugal Pumps ◽  
Turbine Engine ◽  
Positive Displacement ◽  
Pumping System ◽  
Displacement Pump ◽  
Main Engine

Since their introduction, main engine fuel pumping systems for aircraft gas turbine engines have remained relatively unchanged. The main engine fuel pump has been an engine accessory gearbox driven, positive displacement pump (except for the Concorde), until recently when centrifugal pumps were introduced on Pratt-Whitney and General Electric military engines. This paper describes some of the issues that must be addressed as pumping system technology moves into the 21st century and gives a description of two programs that address these issues.

scholarly journals PROTECTION OF CENTRIFUGAL PUMPS FROM ABRASIVE WEAR USING A VACUUM HYDROCYCLONE

2020 ◽  
Vol 1 (383) ◽  
pp. 6-13
Author(s):  
Zh. K. Kassymbekov ◽  
O. V. Atamanova ◽  
K. K. Alimova ◽  
G. Zh. Kassymbekov
Keyword(s):  
Abrasive Wear ◽  
Pressure Gauge ◽  
Dynamic Test ◽  
Field Tests ◽  
Test Method ◽  
Design And Technology ◽  
Centrifugal Pumps ◽  
Borehole Pump ◽  
Suction Line ◽  
Pump Pressure

The design features of the existing design and technology for the protection of downhole pumps of the ECV type from abrasive wear during operation are considered and analyzed. Based on the analysis, a new method for capturing solid impurities on the suction line of a borehole pump of the ECV type using a pressure-vacuum hydrocyclone is proposed. It is specified that at field tests of a prototype of new installation technological process is estimated on the pressure-expense characteristic and technological-operational indicators according to requirements of GOST 6134-81 " pumps dynamic. Test method. " In this case, the flow rate of the base pump on water is determined by means of a turbine water meter mounted on a water-lifting pipe with a valve. The performance of the hydraulic elevator is established by the volumetric method, and the head in front of the valve of the pump pressure pipe using an approximate pressure gauge. It is established that the flow-pressure characteristics of the base submersible pump ECV are provided in full (water flow 60-70 m3/h, head - 110-118 m), overload on the electric motor is not detected (ammeter readings are within the permissible limits-68-71 amperes), the degree of water purification is 95-96%. It is noted that the implementation of a flexible packer device with slots and the presence on the surface of the second minihydrocyclone-thickener significantly improves the functioning of the adopted scheme of water treatment. It turned out that with this technology, the overload of the pump motor is reduced by cooling with water without mechanical impurities.

Analytical and Experimental Investigation of a Passively Controlled Infinitely Variable Positive Displacement Water Pump

2017 ◽  
Author(s):  
John Mullen ◽  
Timothy J. Cyders
Keyword(s):  
Inverse Dynamics ◽  
Order Effects ◽  
Centrifugal Pumps ◽  
Inverse Dynamic ◽  
Pump System ◽  
Positive Displacement ◽  
Improve Model ◽  
Displacement Pump ◽  
Variable Transmission ◽  
Experimental Findings

A passively controlled infinitely variable transmission modeled and experimentally investigated by Cyders (2012), has potential to be combined with a number of different types of mechanisms. The mechanism’s incorporation into a hydraulic pump has many applications of interest; the CVT approach to a positive-displacement pump could provide a combination of the advantages of both positive-displacement and centrifugal pumps in one machine. This work had two main objectives: first, an inverse dynamic analytical model was developed using piece-wise techniques that simulated the behavior of the CVT/PD pump system. Second, this simulation was compared against experimental results, which were generated from data taken from an example system prototype. Predictions were made using an inverse-dynamics model, and were compared against experimental findings generated from a prototype of the system. The simple approach to modeling provided results sufficient to describe the overall pressure-flowrate behavior of the pump at low speeds, but a more sophisticated dynamic approach is still necessary to improve model agreement at high speeds when second-order effects begin to dominate.

One-Dimensional Prediction and Three-Dimensional CFD Simulation of the Fluid Dynamics of Regenerative Pumps

2018 ◽  
Author(s):  
Massimiliano Insinna ◽  
Simone Salvadori ◽  
Francesco Martelli ◽  
Giorgio Peroni ◽  
Gilles Simon ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Performance Estimation ◽  
Side Channel ◽  
Analysis Tool ◽  
Energy Transfer Mechanism ◽  
Centrifugal Pumps ◽  
One Dimensional ◽  
Positive Displacement

Regenerative pumps, also referred to as “peripheral” or “side channel” pumps, are characterized by a specific speed that contextualize them between rotary positive displacement and purely radial centrifugal pumps. Although regenerative pumps are not widely distributed, they are interesting for many industrial applications. In fact, for a given flow rate they operate at lower rotational speed with respect to purely radial pumps. Furthermore, they are less affected by mechanical problems with respect to positive displacement pumps. The energy transfer mechanism is the same of centrifugal pumps, but the presence of the side channel imposes to the fluid to pass several times through the impeller, thus obtaining higher pressure rise (as for multi-stage machines) with respect to classical purely radial pumps. Unfortunately, the complexity of the flow field, the large amount of wetted surface and a disadvantageous inflow/outflow configuration contribute to limit the maximum value of hydraulic efficiency, which is also very sensitive to the design choices. Moreover, the intrinsic complexity of the helical flow path makes the theoretical performance estimation a challenging task. It is worth underlining that an accurate performance prediction using one-dimensional models would allow to accelerate greatly the design process, with a non-negligible reduction of demanding three-dimensional Computational Fluid Dynamics (CFD) campaigns. The aim of the present work is to deeply investigate the fluid dynamics of regenerative pumps and to understand how accurately the fundamental physical phenomena can be reproduced by one-dimensional theory. To comply with these aims, a systematic post-processing of the results of several steady and unsteady three-dimensional CFD simulations is exploited for the validation of the in-house one-dimensional tool DART (Design and Analysis tool for Regenerative Turbomachinery), developed at the University of Florence. The theory underlying DART is detailed, and the assumptions of the model are verified by means of comparison with the numerical results underlining the key aspects to be considered for a reliable prediction of the pump performance.

Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump

2005 ◽  
Vol 128 (2) ◽  
pp. 341-349 ◽  
Author(s):  
Young-Do Choi ◽  
Junichi Kurokawa ◽  
Jun Matsui
Keyword(s):  
Centrifugal Pump ◽  
Reverse Flow ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Positive Displacement ◽  
Speed Range ◽  
Low Specific Speed ◽  
Specific Speed

In very low specific speed range (ns<0.25), the efficiency of the centrifugal pump designed by the conventional method becomes remarkably low. Therefore, positive-displacement pumps have been widely used for long. However, the positive-displacement pumps remain associated with problems such as noise and vibration and they require high manufacturing precision. Since the recently used centrifugal pumps are becoming higher in rotational speed and smaller in size, there appear to be many expectations to develop a new centrifugal pump with high performance in the very low specific speed range. The purpose of this study is to investigate the internal flow characteristics and its influence on the performance of a very low specific speed centrifugal pump. The results show that large reverse flow at the semi-open impeller outlet decreases absolute tangential velocity considerably which in turn decreases the pumping head.

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