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Article

Peng Dong, Shengdun Zhao, Shuqin Fan, Muzhi Zhu and Peng Zhang

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…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Originality/value

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.

Details

Assembly Automation, vol. 40 no. 2
Type: Research Article
ISSN: 0144-5154

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Article

M.H. Cooper

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…

Abstract

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.

Details

Education + Training, vol. 7 no. 12
Type: Research Article
ISSN: 0040-0912

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Article

A.C. SMITH

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

Abstract

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

Details

Industrial Lubrication and Tribology, vol. 9 no. 11
Type: Research Article
ISSN: 0036-8792

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Article

Jorge L. Parrondo, Sandra Velarde and Carlos Santolaria

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…

Abstract

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.

Details

Journal of Quality in Maintenance Engineering, vol. 4 no. 3
Type: Research Article
ISSN: 1355-2511

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Article

Baoling Cui, Xiaodi Li, Kun Rao, Xiaoqi Jia and Xiaolin Nie

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…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Originality/value

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.

Details

Engineering Computations, vol. 35 no. 3
Type: Research Article
ISSN: 0264-4401

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Article

Zhengwei Wang, Guangjie Peng, Lingjiu Zhou and Deyi Hu

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…

Abstract

Purpose

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.

Design/methodology/approach

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.

Findings

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.

Research limitations/implications

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

Originality/value

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.

Details

Engineering Computations, vol. 27 no. 2
Type: Research Article
ISSN: 0264-4401

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Article

R.K. Turton

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

Abstract

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.

Details

Education + Training, vol. 8 no. 11
Type: Research Article
ISSN: 0040-0912

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Article

Shervin Asadzadeh, Behrouz Akhavan and Behnaz Akhavan

In this paper, the performance of a specific gas station (Parvin) has been studied and investigated. The purpose of this research is to design a second-order regression…

Abstract

Purpose

In this paper, the performance of a specific gas station (Parvin) has been studied and investigated. The purpose of this research is to design a second-order regression model based on simulated data to optimize the queuing system in line with the fuel sales and costs. Thus, the influential variables including the number of pumps and the number of pump operators need to be optimally determined.

Design/methodology/approach

The simulation was combined with design of experiments (DoE) techniques to achieve a predictable model for optimizing Gas Station performance considering both the sales rate and the queue length. First, the Gas Station was simulated with Arena software, and then by using DoE and response surface methodology (RSM), the gas station performance was optimized in terms of three objectives including costs. A face-centered central composite design (CCD) has been implemented to reach the optimal number of pumps and pump workers.

Findings

The results of the optimization model derived from the CCD indicate that the performance of the Gas Station system has been improved considerably. Moreover, after the detailed study of optimization and RSM outputs, it seems that the variations of both the pumps and the number of pump operators have significant impacts on the performance of the Gas Station including costs, sales rate and queue length.

Originality/value

In general, it has been proved that simulation-based RSM can be considered as a powerful and effective technique in both single and multi-objective experimental optimization. The present study has been able to help managers to make decisions and conduct the Gas Station in critical conditions in different hours of a day.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 2
Type: Research Article
ISSN: 0265-671X

Keywords

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Article

Hui Quan, Yi Chai, Rennian Li, Guo-Yi Peng and Ying Guo

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However…

Abstract

Purpose

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However, this mechanism, which should be clarified, significantly influences the pump’s efficiency. To comply with the aim of investigating it, the 150WX-200-20 type pump is selected as study object in our present work.

Design/methodology/approach

Numerical simulation is conducted to formulate interactions between flow rate and geometric parameters of circulating flow with certain types of blade while experiments on inner flow are served as a witness to provide experimental confirmation of numerical results. Based on these, we coupled some parameters with the pump’s external performance to study their internal connections.

Findings

It is concluded that separatrix between circulating flow and other turbulent forms is not that clear under low flow rate. With flow increases, hydraulic losses coming of it will be dominant within the front chamber. Besides, we analogized circulating flow to vortices so as to make a quantitative analysis on its progressive evolution with changing flow, and vortices speaking for circulating flow can be divided into two groups. One is called main circulating flow vortex (hereinafter referred to as MCFV), which occurs all the time while subsidiary circulating flow vortices (hereinafter referred to as SCFV) appear in certain conditions. This context discusses the primary phase of our work with intent to follow up further with circulating flow characterized by vortices (hereinafter referred to as CFV). We confirmed that MCFV Vortex 1 (Vor1) directly influences the efficiency while SCFVs only play helping. As the flow goes to the given working condition, fluids in this pump tend to be steady with the size of CFVs getting larger and their shape being regular. Meanwhile, for MCFV Vor2 and Vor4, their geometric parameters are the key factors for efficiency. When CFVs become steady, they absorb other vortices nearby, as they have higher viscosity with the efficiency reaching its maximum.

Originality/value

The research results explore a new way to measure the circulating flow and help work out the causation of this flow pattern, which may be used to improve the vortex pump’s efficiency.

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Article

Chunlei Shao, Zhongyuan Zhang and Jianfeng Zhou

The purpose of this paper is to accurately predict the cavitation performance of a cryogenic pump and reveal the influence of the inlet pressure, the surface roughness and…

Abstract

Purpose

The purpose of this paper is to accurately predict the cavitation performance of a cryogenic pump and reveal the influence of the inlet pressure, the surface roughness and the flow rate on the cavitation performance.

Design/methodology/approach

Firstly, the Zwart cavitation model was modified by considering the thermodynamic effect. Secondly, the feasibility of the modified model was validated by the cavitation test of a hydrofoil. Thirdly, the effects of the inlet pressure, the surface roughness and the flow rate on cavitation flow in the cryogenic pump were studied by using the modified cavitation model.

Findings

The modified cavitation model can predict the cavitation performance of the cryogenic pump more accurately than the Zwart cavitation model. The thermodynamic effect inhibits cavitation development to a certain extent. The higher the vapor volume fraction, the lower the pressure and the lower the temperature. At the initial stage of the cavitation, the head increases first and then decreases with the increase of the roughness. When the cavitation develops to a certain degree, the head decreases with the increase of the roughness. With the decrease of the flow rate, the hydraulic loss increases and the cavitation at the impeller intensifies.

Originality/value

A cavitation model considering the thermodynamic effect is proposed. The mechanism of the influence of the roughness on the performance of the cryogenic pump is revealed from two aspects. Taking the hydraulic loss as a bridge, the relationships among flow rates, vapor volume fractions, streamlines, temperatures and pressures are established.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

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