Search results

This paper aims to present a literature review of remote monitoring systems for water infrastructure in the Global South.

Following initial scoping searches, further examination was made of key remote monitoring technologies for water infrastructure in the Global South. A standard literature search methodology was adopted to examine these monitoring technologies and their respective deployments. This hierarchical approach prioritised “peer-reviewed” articles, followed by “scholarly” publications, then “credible” information sources and, finally, “other” relevant materials. The first two search phases were conducted using academic search services (e.g. Scopus and Google Scholar). In the third and fourth phases, Web searches were carried out on various stakeholders, including manufacturers, governmental agencies and non-governmental organisations/charities associated with Water, Sanitation and Hygiene (WASH) in the Global South.

This exercise expands the number of monitoring technologies considered in comparison to earlier review publications. Similarly, preceding reviews have largely focused upon monitoring applications in sub-Saharan Africa (SSA). This paper explores opportunities in other geographical regions and highlights India as a significant potential market for these tools.

This review predominantly focuses upon information/data currently available in the public domain.

Remote monitoring technologies enable the rapid detection of broken water pumps. Broken water infrastructure significantly impacts many vulnerable communities, often leading to the use of less protected water sources and increased exposure to water-related diseases. Further to these public health impacts, there are additional economic disadvantages for these user communities.

This literature review has sought to address some key technological omissions and to widen the geographical scope associated with previous investigations.

The drive shaft and the distribution shaft of a traditional radial piston pump are in a cantilever state. To solve this problem, this paper aims to present a radial piston pump with through shaft driving and valve plate distribution.

The working principle of the pump is discussed in detail. In this radial piston pump, valve plate distribution parts are designed to distribute oil to the piston chambers, and the distribution shaft is replaced. A bearing is installed between the stator and rotator to reduce the friction. The transmission shaft is supported by two bearings to ensure smooth operation. The support force of the transmission shaft is optimized. In addition, the flow pulsation principle is presented. To accomplish the change, the displacement of the radial piston pump, the proportional control system is designed.

After completing the machining and assembly of the pump, an experimental study was carried out. The results show that the output flow of the pump is basically the same as the theoretical flow.

The friction between the slipping shoes and the stator is greatly reduced due to the function of rolling bearings. The higher stability of the driveshaft is obtained for the reason of double-sided support. The radial piston pump has a novel structural design in reducing the friction between the shoes and the stator and improving the stability of the transmission shaft.

As a result of the revisions at present being made to the science syllabus for schools, a large number of teachers in grammar and secondary modern schools are finding themselves involved for the first time in the mysteries of high vacuum. This article is intended as a guide to the practical aspects of obtaining and demonstrating high vacuum in schools. It contains a brief description of the workings of modern high vacuum pumps and gauges, together with some elementary ‘dos and don'ts’ of vacuum technique.

The first part of this article dealing with Degrees of Vacuum, Pump Design, Use of Cold Traps, etc., appeared in our October issue.

The purpose of this paper is to provide a new hydrostatic actuator controlled by a piezoelectric piston pump and to reveal its characteristics.

In this paper, a piezoelectric pump with passive poppet valves and hydraulic displacement amplifier is designed as a new control component in a hydrostatic actuator for high actuation capacity. A component-level mathematical model is established to describe the system characteristics. Simulation verification for cases under typical conditions is implemented to evaluate the delivery behavior of the pump and the carrying ability of the actuator.

By using the displacement amplifier and the passive distributing valves, simulation demonstrates that the pump can deliver flow rate up to 3 L/min, and the actuator controlled by this pump can push an object weighing approximately 50 kg. In addition, it is particularly important to decide a proper amplification ratio of the amplifier in the pump for better actuation performance.

The piezoelectric pump presented in this paper has its potential to light hydrostatic actuator. The model constructed in this paper is valid for characteristic analysis and performance evaluation of this pump and actuators.

An approach is presented for the development of a predictive maintenance system for rotor‐dynamic pumps, which focuses on the diagnosis of abnormal events related to fluid‐dynamic operating conditions. This methodology is based on an experimental characterization of the dynamic response of the pump under different loads and operation anomalies. The procedure has been put into practice on a medium‐sized centrifugal pump. The results obtained show that a simple spectral analysis of the pressure signals captured at either the inlet or the outlet of the pump can provide sufficient decision criteria to constitute the basis for a diagnostic system. This was not true however when analyzing signals of acceleration at the pump casing.

Radial vibration of horizontal centrifugal pump has a close association with radial exciting forces. The purpose of this paper is to analyze the unsteady radial force in multistage centrifugal pump with double volute in detail and investigate the relevance of static pressure, radial force and radial vibration.

The unsteady numerical simulation with realizable k-ε turbulence model was carried out for a multistage centrifugal pump with double volute using computational fluid dynamics codes Fluent. The performance tests were conducted by use of a closed loop system and performance curves from numerical simulation agree with that of experiment. Vibration tests were carried out by vibration probes instrumented on the bearing cover of pump near no-driven end. Fast Fourier transform was used to obtain the frequency components of radial forces on the impellers from numerical simulation, which are compared with ones of radial vibration from experiment in Y and Z direction. And the static pressure distributions in the impeller were analyzed under different flow rates.

The symmetrical double volute can effectively balance radial forces. The maximum radial force and vibration velocity appear at 0.6 Q among the three flow rates 0.6 Q, Q and 1.2 Q. The frequencies corresponding to relatively large amplitude of vibration velocities and radial forces on the impellers in Y direction are blade passing frequency of the impellers. Blade passing frequency of first-stage impeller and shaft frequency are predominating in Z direction. It indicates that the radial vibration of centrifugal pump is closely related to the unsteady radial force.

The unsteady radial forces of the impeller in multistage centrifugal pump with double volute were comprehensively analyzed. The radial forces should be considered to balance during the design of multistage centrifugal pump.

The pump of the Taipuhe Pump Station, larger flow discharge, lower head, is one of the largest 15° slanted axial‐flow pumps in the world. However, few studies have been done for the larger slanted axial‐flow pump on safe operation. The purpose of this paper is to analyze the impeller elevation, unsteady flow, hydraulic thrust and the zero‐head flow characteristics of the pump.

The flow field in and through the pump was analyzed numerically during the initial stages of the pump design process, then the entire flow passage through the pump was analyzed to calculate the hydraulic thrust to prevent damage to the bearings and improve the operating stability. The zero‐head pump flow characteristics were analyzed to ensure that the pump will work reliably at much lower heads.

The calculated results are in good agreement with experimental data for the pump elevation effects, the performance curve, pressure oscillations, hydraulic thrust and zero‐head performance.

Since it is assumed that there is no gap between blades and shroud, gap cavitations are beyond the scope of the paper.

The paper indicates the slanted axial‐flow pump characteristics including the characteristic curves, pressure fluctuations, hydraulic thrust and radial force for normal operating conditions and zero‐head conditions. It shows how to guarantee the pump safety operating by computational fluid dynamics.

A range of small self‐contained hydraulic machine test sets are now available which permit small groups of students to obtain the usual performance characteristics of pumps and turbines with some ease‐though at the expense of efficiency due to scale effects. As most lecture courses include the application of pumps to systems as well as the basic considerations affecting pump performance, it was felt that a layout that allowed the student to combine two pumps in series and then in parallel would introduce him to the hydraulic considerations involved as well as give a more flexible piece of equipment that would permit these tests and a performance test to be conducted (for the basic performance curves would have to be produced first). The apparatus evolved is described, and skeleton laboratory instructions are attached as an appendix. When two similar pumps are connected in series, the fluid passes through each in turn, and the total head produced is approximately double that of one pump as illustrated in figure 1. When two similar pumps are connected in parallel, the total head produced is that of one pump, but the flow is approximately doubled, as shown in figure 2. Figure 3 is a diagrammatic layout of the hydraulic system. The apparatus consists basically of two similar pumps A and B which can be run as single units, connected and operated in series, or connected and run in parallel as will be seen from figure 3, the valves 2 and 4 are closed when series operation is desired, and flow controlled by valve 6; when operation in parallel is required valve 3 is closed, all others being open. A single sump tank is provided, flow measurement is achieved by simple volumetric means and pressure is measured by bourdon‐type gauges, a, b, c and d. The pumps are supplied by Stuart Turner with a duty of 50 feet at approximately 1300 gpm at 2900 rpm, they may operate at 1450 rpm or 2900 rpm, are provided with swinging stators for torque measurement and with a revolution counter for average speed determination. As will be seen from the appendix, the sequence of tests to be performed requires the student to obtain the basic performance characteristics of each pump at the two rotational speeds possible, and to compare them using the Similarity laws; then to test the pumps connected in series and parallel and to compare the performance obtained with that predicted. Figures 4 and 6 give some typical curves and show that the actual performances in series and parallel do not quite fulfil those predicted ignoring losses‐the student is required to consider the contributory factors in his discussion. The writer is grateful to Plint and Partners Limited for their co‐operation.

The purpose of the paper is to disclose the effect of the relative position (d) between the impeller and non-vane cavity on the hydraulic performance and unsteady characteristics of vortex pump.

Three groups of vortex pump models with different impeller installation positions were analyzed and studied by combining experimental and CFD (Computational Fluid Dynamics) numerical calculations.

The steady numerical results show that as the width (d) of the impeller moves into the non-vane cavity increases, the proportion of circulation flow in the non-vane cavity is reduced and both the pump head and efficiency are on the rise. The unsteady numerical results and the Enstrophy analysis show that the dynamic and static interference between the circulation flow and the volute tongue is the main reason for the pressure pulsation with a frequency of 2fn in the vortex pump. With the increase of the d value, the dynamic and static interference between the circulation flow and the volute tongue is enhanced. The pulsation amplitude at the volute tongue of the d = 16.5 mm model increases about six times compared with the d = 0 mm model; the distribution of the vortex core in the non-vane cavity is closely related to the position of the impeller, and the peak of the Enstrophy of the circulation flow vortex belt always appears at the top of the impeller.

The research results provide a theoretical foundation for the optimization and improvement of the vortex pump.