Liquid injection molding II. Mechanical design and characterization of a RIM machine

A unique liquid injection molding machine for polyurethane was designed and built to process a large quantity of polyurethane in a short period of time. This machine has a continuously variable flow rate. Using inexpensive, low capacity gear pumps, 5 gallon hydraulic accumulators were charged with fluid components. The fluid can be pumped into the accumulators at low pressure followed by nitrogen gas addition to the bladders to raise the fluid pressure, or the charging pumps can pump up the accumulators against an existing pressure. The two components were then discharged under pressure through linkage activated ball valves and mixed together in a mixing chamber. The system provided for a very low pressure loss during discharge, resulting in high fluid velocity. Extremely high flow rates were possible: approximately 1440 lb/min at 2500 psi, a pressure less than the maximum possible system pressure. This system delivers large flow rates of high quality urethane while still maintaining its simplicity, light weight, and relative low cost.     

钻井泵泵阀运动特性的系统分析

通过研究钻井泵泵阀运动的基本规律,构造了在排出阀、吸入阀联动作用下单缸套泵阀运动数学模型,实现了单缸套泵阀运动过程中动力学特性的系统描述。建立了钻井泵泵阀仿真流程和逻辑运行框图,采用Delph i语言实现了单缸套泵阀运动的系统仿真。仿真研究表明,泵阀的运动特性与阀盘结构、缸套结构、钻井液性能、曲轴转速等参数之间存在非常密切的联系。     

Energy optimization of water supply system scheduling: Novel MINLP model and efficient global optimization algorithm

This article is concerned with global optimization of water supply system scheduling with pump operations to minimize total energy cost. The scheduling problem is first formulated as a non‐convex mixed‐integer nonlinear programming (MINLP) problem, accounting for flow rates in pipes, operation profiles of pumps, water levels of tanks, and customer demand. Binary variables denote on–off switch operations for pumps and flow directions in pipes, and nonlinear terms originate from characteristic functions for pumps and hydraulic functions for pipes. The proposed MINLP model is verified with EPANET, which is a leading software package for water distribution system modeling. We further develop a novel global optimization algorithm for solving the non‐convex MINLP problem. To demonstrate the applicability of the proposed model and the efficiency of the tailored global optimization algorithm, we present results of two case studies with up to 4 tanks, 5 pumps, 5 check valves, and 21 pipes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4277–4296, 2016     

多功能水泵控制阀在水泵系统中的应用

分析了传统水泵系统配置存在的弊端,阐述了多功能控制阀的结构和工作原理,介绍了此类阀门在水泵系统中的应用情况及效果。     

Automation of a flow injection system for the determination of dissolved silver at picomolar concentrations in seawater with inductively coupled plasma mass spectrometry

An automated flow injection system for the determination of dissolved silver at ultratrace concentrations in seawater, and controlled under LabVIEWtrade mark, is described. The flow injection system allows online processing of seawater samples before their analysis using a magnetic sector inductively coupled plasma mass spectrometry (MS-ICP-MS) instrument. Samples were analysed with a minimum amount of manipulation, thereby reducing the risk of contamination. In addition, the flow injection approach with incorporation of an anion exchange minicolumn allowed ready removal of analytical interferences caused by the saline matrix. The software allowed full control of all flow injection components (valves and pumps) and removed manual time control and, therefore, operator errors. The optimized system was capable of five sample injections per h, including preconcentration and wash steps. The limit of detection was 0.5 pM for a 240-s sample load time, which allowed the determination of dissolved silver in open ocean waters, where picomolar concentration levels are typically encountered.     

智能电液执行装置在出水阀门上的应用

该文介绍了智能电液执行装置在水厂、泵站出水阀门上的应用及创新驱动供水行业水厂及泵站在节能降耗方面的新思路。改变自来水厂二泵房和泵站出水管路上设置单向阀的传统规范设计,由智能电液执行装置所控制的阀门来替代。在出水管路上省去一个单向阀,减少了出水管路上的水头损失,符合设计要求、运行安全,是一项有效的节能措施。     

止回阀对给水系统水锤的影响

给水系统中止回阀的存在是为了防止管路中的逆流过大破坏泵及其他设备,而安装止回阀又会影响系统水锤发生时的压力和流量.利用AFT impulse软件建立核电站给水系统的模型,模拟在突然停泵和阀门突然关闭时有无止回阀以及不同止回阀类型对系统水锤的影响,从中看出无止回阀时虽然系统中的水锤最大压力不大,但是逆向流量很大;普通止回阀的存在有效地抑制了管路中的水倒流,但同时增大了水锤压力;可控缓闭止回阀结合了两者的优点,既降低了水锤最大压力,又可以把管路中水逆流控制在合理范围.     

泵与工艺设备自动紧急隔离阀设计探讨

分析探讨了泵与工艺设备紧急隔离阀的设置原则。对紧急隔离阀阀型结构的选择以及安装做了简单说明。参考API607的说明对紧急隔离阀的防火测试做了简要说明。并对紧急隔离阀执行机构的设计和选型进行了深入探讨。结合相关案例对紧急隔离系统的相关安全联锁的设置原则做了简单阐述。     

凝结水泵出力不足的问题排查、分析与处理

离心泵是化工、电力生产中的重要输送设备,凝结水离心泵（凝结水泵）是电厂中的重要辅助设备。某电厂在试运期间,在机组高负荷时,凝结水泵发生汽蚀现象。分析了凝结水泵发生出力不足的原因,并通过对凝结水泵入口蝶阀进行改造,消除了出力不足的设备缺陷,提高了凝结水泵运行的安全性和经济性。     

硫酸装置低温热回收用JSB合金的研发与应用

实现低温位热能回收是目前硫酸生产的趋势,同时对硫酸生产装置中的设备材质提出了更高要求。为了满足低温位热能回收的要求,昆明某公司研发了JSB系列合金材料,成功应用于低温位热能回收系统的循环酸泵、管槽式分酸器、酸排出泵、蒸发器、各式阀门和管道附件等,取得了很好的效果。     

The hydrodynamic behavior of the liquid-solid circulating fluidized bed ion exchange system for cesium removal

In this work, experimental studies on the hydrodynamics have been carried out in a cold model liquid-solid circulating fluidized bed (LSCFB) ion exchange system where the riser is operated in the circulating fluidization regime and the downcomer in the state of slow-moving packed bed, with the aim of removing cesium from high radioactive liquid waste. Two circulating fluidization zones, the initial and the fully developed, have been observed. The solids circulation rate can be controlled merely by the primary liquid flow if the auxiliary liquid flow is set to zero and the injection tap is located at the middle of the intersection of the riser and the solid-return pipe. Therefore, it is possible to minimize the number of the liquid feed assemblies (pumps, valves, flow meters, etc.), and this is crucial to the treatment of high radioactive waste. The liquid inevitably leaks through the solid-return pipe in most cases because of the “loosening effect” of the liquid feed flow, and the direction and magnitude of the leakage vary with the operating conditions. The system geometry, including the injection tap location and the riser outlet location, plays a very important role in the hydrodynamics of the LSCFB system.     

Design of an Automated Flow Injection-Chemiluminescence Instrument Incorporating a Miniature Photomultiplier Tube for Monitoring Picomolar Concentrations of Iron in Seawater

A flow-injection (FI)-based instrument under LabVIEW control for monitoring iron in marine waters is described. The instrument incorporates a miniature, low-power photomultiplier tube (PMT), and a number of microelectric and solenoid actuated valves and peristaltic pumps. The software allows full control of all flow injection components and processing of the data from the PMT. The optimised system is capable of 20 injections per hour, including preconcentration and wash steps. The detection limit (3 sd of the blank) is 21 pM at sea and the linear range is 21–2000 pM with a 60-second sample load time. Typical precision between replicate FI peaks is 5.9 ± 3.2 % (n =4) over the linear range.     

安全阀的现场整定

安全阀是一种安全保护用阀，是为了保证锅炉、压力容器和压力管道的安全运行，在出现超压时为保护系统安全而进行有效泄的安全附件。安全阀被广泛应用在输油泵、带压油罐等压力管道系统和高压锅炉、过滤器等压力容器上，对设备的安全运行提供了有力保障。     

石油天然气工程安全阀选型与热泄放计算

安全阀是一种安全保护用阀,是为了保证锅炉、压力容器和压力管道的安全运行,在出现超压时为保护系统安全而进行有效泄的安全附件。安全阀被广泛应用在石油天然气工程中的输油泵、带压油罐等压力管道系统和高压锅炉、过滤器等压力容器上,对设备的安全运行提供了有力保障。     

机械密封冲洗用限流阀性能试验研究

本文介绍了机械密封冲洗用限流阀的性能试验结果，推荐了平头阀芯顺流直角阀的３种规格，以满足有关石油化工用泵机械密封对冲洗量的不同要求。通过用水、煤油和机油等３种价质进行试验，得出了近似计算用的ｈ－Ａ－αＡ曲线，以用来确定限流阀的流量系数α。     

乙烯分离流程联塔系统的大规模联立动态模拟

在乙烯生产流程中,以脱丙烷塔与脱丁烷塔的复杂联塔系统作为研究对象,根据机理建立双塔联立的动态数学模型.该联塔数学模型是一个大规模的微分代数混合系统(DAEs),包括了精馏塔、控制器、阀门、泵等多种操作单元和设备.动态模拟实质即为求解这个大规模的DAE系统.文章以动态模拟软件gPROMS为建模工具和模拟环境,通过调用大规模DAE求解算法,模拟联塔的动态操作过程,并与Aspen Plus稳态模拟结果进行了比较和分析.     

An automatic dehydrogenase-based flow-injection system: Application for the continuous determination of glucose and lactate in mammalian cell-cultures

A concept for the development of an automatic flow-injection analyzer with integrated dehydrogenase columns and its application in the control of industrial processes is presented. The system is based upon a kernel consisting of a nested-loop injection unit, pumps for the filling of the injection loops and the transport of buffer and valves for switching on the one hand between sample and standard solutions and on the other hand between different enzyme columns. A Microsoft Windows 3.x application ‘WIN-FIA’ controls interactively the whole system and can be easily adapted to a specific solution of an analytical problem. As an example, the flow-injection system was used for the continuous determination of glucose and lactate, using glucose dehydrogenase (GDH) and lactate dehydrogenase (LDH) as indicator enzymes, in a mammalian cell-culture fermentation process. The resulting concentration values are in good agreement with those obtained by discontinuously taken standard spectrophotometric enzyme assays.     

Automated gradient-elution column chromatography of lipids

An automated gradient-elution chromatography system was developed specifically for the separation of complex mixtures of naturally occuring lipids obtained from various tissues. It uses silica gel columns with concave gradients of increasing polarity. These gradients offer advantages over the convex type because of the absorptive properties of most lipid classes on silica gel. The entire system is operated automatically once the charge is placed on the column. The flow rate is constant throughout the run and the shape of the gradient is predetermined by selecting known values for three parameters. The selection of the gradient is arbitrary but previous knowledge of the chromatographic behavior of the substances to be separated is useful in determining the shape of the gradient. The entire system is controlled by timers, pumps, and solenoid valves. Details of the construction of the apparatus are described and criteria for the selection of acceptable pumps for organic solvents are discussed. Several examples of the separations obtained with the system are described. While silica gel was used as the adsorbent, there is no reason to believe that other adsorbers cannot be substituted for other application. In addition, column size and elution times can be changed to provide better resolution for the specific problems, greatly broadening the application of liquid column chromatography, particularly in the area of routine quantitative analysis of nonvolatile substances. Nongradient elution can also be performed by this apparatus.     

Verbesserung von Qualität und Wirtschaftlichkeit durch Dosierpumpen in der Öl- und Fett-verarbeitenden Industrie

Improvement of Quality and Economy in the Oil and Fat Processing Industry by the Use of Metering Pumps Volumetric metering of liquids using metering pumps is discussed with special reference to the following aspects: Limits of application, requirements to be met by the metering pumps in the oil and fat industry, types of metering pumps, forms of construction, drives and gears, pump heads, cylinder packings, pump valves, influence of external conditions, installation of metering pumps and their regulation. The economic solution of tasks involving metering is shown with examples from the practice.     

Pumpen und Verdichter für hohe Drücke — Festigkeit,Dichtungen, Verschleiß

Pumps and compressors for high pressures – strength, seals, wear . In high pressure processes pumps and compressors are used for the pressure range of 100 to 4 000 bar. Very careful design is necessary because of the extreme mechanical demands. The special features of high pressure technology are explained. The methods used for generating high pressures – displacement or fluid flow machine – impose design limitations, partly by the final temperature, Mach number, material fatigue, or vibrations. A survey of typical high pressure pumps and compressors shows the range and limitations of application. There is a definite trend to leak-free systems. The best design of thick-walled components with pulsating pressureload avoids grooves, requires smooth surfaces, and uses tough, clean, and high-strength steels. The various designs of dynamic seals are explained and the state of the art is depicted. Detailed reference is also made to the exceptionally difficult wear problem of oscillating pump valves with abrasive suspensions.