Set Of Solenoid Valves Research Articles

A New Physics-Informed Condition Indicator for Cost-Effective Direct Current Solenoid Valves Using Significant Points of the Excitation Current

AbstractThis paper proposes a new condition indicator (CI) for cost-effective industrial direct current (DC)-powered solenoid valves (SVs). First, a literature review of the failure modes for SVs is reported. The failure regarding the impeded movement of the valve plunger is considered. The proposed CI for this failure mode is computed from only some significant points of the SVs excitation current and their time instants. The proposed CI is evaluated by a large endurance campaign on a set of SVs. Then, a Remaining Useful Life (RUL) estimation algorithm is proposed and evaluated on the experimental data. Experimental results show the goodness of the proposed CI for RUL estimation of cost-effective industrial DC SVs.

Automatic multicommuted flow-batch setup for photometric determination of mercury in drinking water at ppb level

Herein, a multicommuted flow-batch setup and a photometric procedure for the determination of mercury at the ppb level in aqueous samples are described. The setup was designed to implement a versatile solvent extraction and pre-concentration strategy by combining flow-batch and multicommuted flow analysis approaches. The photometric method was based on Hg(II) reaction with dithizone in a chloroform medium, which was also used as the extracting organic solvent. The flow analysis system was composed of a homemade syringe pump module, a set of solenoid valves, two Aquarius mini-pumps, and a flow-batch chamber. The homemade photometer was comprised of a light emitting diode (LED), photodiode, and homemade flow cell (50 mm length). The flow system and photometer were controlled using an Arduino Due board, running custom-written software. After optimizing the operational conditions, the effectiveness of the developed system was evaluated for the determination of the mercury concentration in drinking water. For accuracy assessment, samples were analyzed using a spiking methodology and an independent method, yielding a recovery ranging from 92% to 108%. Other important characteristics of the proposed method were found as follows: linear response range, 0.5–10.0 μg L−1 (r = 0.9984); limit of detection 0.38 μg L−1 Hg(II); consumption of dithizone and chloroform, 1.85 μg L−1 and 0.8 mL per analysis, respectively; coefficient of variation, 2% (n = 10); sampling throughput, 20 determinations per h.

Automatic Procedure to Determine Acidity in Fuel Ethanol by Photometric Titration Using Binary Search and Multicommuted Flow Analysis

An automatic photometric titration procedure was developed to determine the acidity of fuel ethanol. The procedure was implemented by using a binary search algorithm and a multicommuted flow analysis approach. Solution-handling setup included a homemade syringe pump and a set of solenoid valves, which were assembled to treat the solution-handling as a time function controlled by a microcomputer. Photometer detection was performed using a compact homemade light emitting diode (LED)-based photometer. Aiming to evaluate the accuracy, samples were analyzed by employing the methodologies recommended by the Brazilian Association of Technical Standards (ABNT) and the American Society for Testing and Materials (ASTM). Accuracy was assessed by applying the Student’s t-test for paired samples at the 95% confidence level (n = 4), which shown that there is no significant difference between results. Other useful features included relative standard deviation of < 1% and waste generation volume ten times lower than those produced by ABNT and ASTM methods.

Development of an Automated Tension Infiltrometer for Field Use

Tension infiltrometry is a useful in situ technique that is commonly used to determine hydraulic conductivity of the soil near saturation; however, the measurements are time consuming and costly. The aim of this study was to develop a fully automated tension infiltrometer for field use based on already existing designs. Differential pressure transducers were used to automate water level measurements, and the tension settings were automated by a set of solenoid valves. The effects of different design parameters on water level measurement fluctuations created by bubble disturbances (noise) were studied in the laboratory. The differential transducer provided less noisy measurements than the single transducer. The measurement noise was significantly smaller when a large‐diameter reservoir was used. The measurement noise was further reduced by using a reservoir system made of two tubes of different diameters slotted into each other. The effect of an increasing flow rate on the water level fluctuations was also investigated. Based on the design parameters tested, three identical tension infiltrometers connected to a single Mariotte bottle were built and tested under laboratory and field conditions. The pressure‐dependent hydraulic conductivity, K(h), values for all three replicates applied in the laboratory did not significantly differ from each other. In the field, the infiltration experiments were performed on a sandy loam soil on sites with and without wheel tracks. A significant reduction of K(h) values for most of the applied pressure heads was observed in the wheel track. The improved automated tension infiltrometer requires only a little operator intervention.

A CASE STUDY ON FMEA APPLICATIONS TO SYSTEM RELIABILITY STUDIES

Failure Mode and Effect Analysis (FMEA) has been used quite extensively in aerospace industry for several years to establish hardware criticality. Determination of software reliability is equally important. There are several methods for determining software reliability. One methods for performing software reliability is the software FMEA. This paper discusses the application of principles to FMEA. A typical Tank pressurant is considered as an illustrative example. The tank pressurant system consists of three sets of solenoid valves (each set consists of a pair of valves), three pressure transducers, a vent valve, a heat exchanger and helium cold pressure bottles. Each set of solenoid valves consist of two solenoid valves connected in series. For the system to function properly, certain conditions have to be met. These are discussed in detail later in this paper. Based on the information provided from NASA, it is concluded that FMEA has to be capable of determining the software failure modes, effects and criticality as well as the hardware failure modes effects and criticality which includes the pressure transducers, solenoid valves, vent valve, heat exchanger and helium cold pressure bottles. The paper will discuss both the hardware and software FMEA application in detail.

Modulation of mobile phase composition in flow-injection/sequential-injection chromatography exploiting multisyringe flow analysis

In this paper, a time-based multicommutated flow system is proposed for appropriate selection and modulation of mobile phase composition in flow-injection (FI)/sequential-injection (SI) chromatography. The novel flow assembly involves the on-line coupling of a short monolithic reversed-phase chromatographic column with a multisyringe flow injection set-up furnished with a set of solenoid valves. The proposed hyphenated technique was applied to the simultaneous spectrophotometric determination of thiamine (B(1)), pyridoxine (B(6)) and cyanocobalamin (B(12)) which were taken as model analytes. The separation method capitalizes on a dual isocratic elution protocol involving the use of a single forward stroke of the multisyringe pump for initial delivery of 50 mmol L(-1) ammonium acetate (pH 7.0) for 2.4 min followed by 50 mmol L(-1) ammonium acetate-methanol (80:20, v/v) for 6.4 min at 0.5 mL min(-1) and room temperature. Detection was performed at the maximum wavelength for each target vitamin-280 nm for B(1), 325 nm for B(6), and 360 nm for B(12). A first-order, two-level full-factorial design was utilized to ascertain the significant variables influencing the chromatographic separation and the magnitude of the interaction effects. The experimental design method revealed that resolution of the target vitamins is highly dependent on the pH, percentage of organic modifier, and their second-order interaction. The multisyringe flow-injection-based monolithic column separation method, which should be viewed as an expeditious and cost-effective alternative to the high-performance liquid chromatography counterpart, was applied to the separation and determination of B(1), B(6), and B(12) in different pharmaceutical dosage forms in less than 9 min. Statistical comparison of the results from the proposed procedure with those from the HPLC method endorsed by the US Pharmacopeia revealed there were no significant differences at the 95% confidence level.

Application of Forced Oscillating Combustion to Burners for an Industrial Furnace. Evaluation of NOx Reduction Effect.

Forced oscillating combustion can reduce nitrogen oxides (NOχ) emission, as described previous researches. In this paper, in order to estimate the effect on NOχ reduction, the concept is applied to two kinds of commercial burners for use in industrial furnaces. Natural gas is supplied through a set of solenoid valves, which are alternately made open and close at several times a second with various duty ratios, whereas preheated air from a recuperator is supplied at a fixed rate. Combustion products are sampled at the exit of recuperator and analyzed using a series of analyzers. It is found that about 30% reduction of NOχ emission is realized by introducing forced oscillation combustion into two kinds of industrial burners, exclusive of an operation of long turbulent jet flame.

Micro flow system to perform programmable isotope dilution for inductively coupled plasma-mass spectrometry

A flow system using computer controlled devices to implement binary sampling of small volumes of sample and spike solutions was coupled to an inductively coupled plasma-mass spectrometer to perform programmable isotope dilutions. A computer running software in QuickBasic controlled the time-based sampling of sample and spike solution by switching on/off a set of solenoid valves. Mixing was improved by sampling 15 small aliquots of both solutions at a flow-rate of 65 μl min −1 through a capillary tubing connected to a micro-concentric nebulizer (MCN). Each aliquot of 6 μl containing the sample plus spike was introduced during 4 s. Programming the sample to spike volumetric ratios in each aliquot allowed to perform different isotopic dilutions generated from a single enriched solution. The flow system was calibrated measuring the isotopic ratios of 112 Cd/ 114 Cd by binary sampling of natural abundance Cd solutions as sample and enriched 112 Cd (97 at.%) solution as spike. The programmed and the measured ratios in the range from 6 to 25 presented good correlation (0.997). For routine analysis, using an estimate analyte concentration, and the isotope ratio within the defined range, the software calculates the time delays to introduce the sample and spike volumes. The true and found concentrations for solutions containing from 2.0 to 20.0 μg l −1 Cd attained good agreement at the 95% of confidence level. For these solutions the consumption of enriched 112 Cd (97 at.%) ranged from 33 to 168 pg per determination. About 30 isotope dilutions per hour were achieved.

Extracellular perfusion controller for electrophysiology

This paper describes the design and utility of a perfusion controller to facilitate the handling of multiple extracellular solutions. The controller consists of an interface box with both manual and computer controls and a set of solenoid valves. This provides remote handling of the switching of multiple solutions into an experimental chamber. It is described how this system can be used in whole-cell patch-clamp experiments to measure various ion channel currents as well as Na/K pump currents. Other possible uses are discussed along with suggestions for interfacing the perfusion controller with existing perfusion systems.

A simple automatic phototitrator for the determination of total carbonate and total alkalinity of sea water

An automatic photometric analyser based on the reversed use of a conventional motor syringe buret and modern optoelectronic components is described. The buret serves as a photometric titration vessel into which sample and reagents are selectively drawn through a set of solenoid valves. It has been applied to the photometric titration of total alkalinity and total carbonate concentration of sea water, giving precisions of 0.10% and 0.13%, respectively.