Switching Valve Research Articles

Optimization of valve switch control for contamination detection in water distribution network

Optimization of valve switch control for contamination detection in water distribution network

CFD-based axial steady-state hydrodynamic study and structural optimization of miniature switching valve

CFD-based axial steady-state hydrodynamic study and structural optimization of miniature switching valve

Dynamics and experimental study of a novel proportional directional valve with displacement feedback groove controlled by high-speed switching valves

The intelligence of hydraulic roof support is an important guarantee for unmanned fully mechanized coal mining face. The water-based medium proportional directional valve is the main factor that restricts the intelligent realization of support system. The support control valve needs to meet the 2/3 (two-position three-way) structure, taking into account both manual and electro-hydraulic control functions. The current water-based proportional valve does not satisfy the structural or functional demands of the support system. In this paper, a novel 2/3 water-based proportional directional valve is presented based on the displacement-flow feedback principle, which has two control modes: manual on-off control and electro-hydraulic proportional control. The proportional valve comprises two main valve spools and two pilot valves. The pilot valve is composed of a 2/3 on-off valve with manual operation capability and a high-speed switching valve group controlled by PWM (Pulse Width Modulation). The mathematical model of the proportional valve is established, and the experimental system is built to verify the characteristics of proportional valve. The proportional valve can meet the special functional requirements of the support. In the proportional control mode, the adjustment of spool displacement is regulated through the modulation of PWM duty ratio, resulting in effective control performance of the proportional valve. Furthermore, the discontinuous flow of the high-speed switching valve causes the pressure fluctuation of the pilot hydraulic bridge. Increasing the carrier frequency of PWM can reduce the amplitude of control chamber pressure and spool displacement fluctuation. The findings of the study can offer valuable insights for the continued advancement and enhancement of water-based proportional valves used in hydraulic roof support systems.

Stability Analysis Of Two-Position Control System In Interacting Tanks Using Describing Function Method

In a water storage unit consisting of 3 interacting tanks, in its operation there will be problems if manual control is used, because if manual control is not optimal, then when filling water in the three tanks it will cause water overflow, which results in a lot of water being wasted. Two-position control, or "on-off," is a control system that is suitable for use in regulating the water level in the storage unit tank. In a two-position control system, if the frequency of water up and down (Limit Cycle) is large, it will cause an increase in the number of "switching" and "on-off" operations of the switch and solenoid valve per minute, so that the system becomes unstable and will shorten the life of the component. The Describing Function (DF) method is an analysis method that can determine the Limit Cycle frequency based on the width of the water up and down range (hysteresis) of the two-position control system, with the aim of determining the hysteresis parameters that cause the system to be stable.

Efficiency enhancement of bicycle anti-lock braking systems (ABS): Design and optimization of solenoid actuators through finite element analysis and performance simulation

The rising popularity of cycling underscores the need for enhanced safety, particularly under challenging braking conditions. This study introduces a novel high-power switch valve designed explicitly for Bicycle Hydraulic Disc Brakes (BHDBs), incorporating Hydraulic Anti-lock Braking Systems (ABS). Comprehensive Finite Element Analysis (FEA) modeling and subsequent optimization of an existing solenoid valve’s internal geometry were performed through 2D and 3D simulations to evaluate magnetic flux. The improved design achieved a maximum output force of 280 N with a linear stroke of approximately 3.5 mm. Notably, the enhanced system exhibited a 28% reduction in required current, from 5.0 to 3.6 A, a result validated through LabVIEW-equipped custom tests, which stress the credibility of the research. This study underscores significant advancements in high-power switch valves for BHDBs, promising enhanced braking efficiency and safety in high-performance, battery-powered bicycles. These findings not only promise enhanced safety for cyclists but also suggest the potential for broader application in energy-efficient and sustainable bicycle ABS technology, contributing to improved cyclist safety without compromising the environmental and health benefits of cycling. The potential impact of this research extends beyond the immediate context, offering insights that could be applied to other areas of technology and safety.

Rapid and simultaneous determination of ultrashort-, short- and long- chain perfluoroalkyl substances by a novel liquid chromatography mass spectrometry method

Per- and Polyfluoroalkyl Substances (PFAS) are a group of persistent organic pollutants that have received considerable attention from public and regulatory groups. Due to regulations of long-chain PFAS, the use of short-chain and ultrashort-chain PFAS is rapidly growing. Thus, there is an urgent need to develop quantitative methods for determining PFAS with different chain lengths in various environmental matrices. This study introduces an innovative liquid chromatography-mass spectrometry (LC-MS) system combining large volume injection (LVI) and online solid phase extraction (SPE). This system incorporates three columns: a reverse-phase (RP) column, a weak anion exchange (WAX) trap column, and a hybrid HILIC/ion-exchange (HILIC/IE) column, controlled by two valves. With valve switching, ultrashort-chain PFAS that are not retained by the RP column are enriched by the trap column, while other PFAS are separated by the RP column. The trapped ultrashort PFAS are then transferred to the HILIC/IE column for further separation. The LVI significantly enhances the method's sensitivity, allowing for rapid and simultaneous determination of ultrashort-, short- and long- chain PFAS in aqueous samples. The matrix effects from various environmental samples were evaluated, and the results indicate that this unique LC-MS method is suitable for analyzing all chain-length PFAS in various matrices, including surface water, sewage effluent, and seawater. Finally, this novel LC-MS method was applied to quantify PFAS in various water samples.

Employing a switching valve to automate external standard calibration in inductively coupled plasma optical emission spectrometry

The traditional external standard calibration method (EC) is automated and simplified using a four-port switching valve (SV4) and a multi-signal approach that enables the generation of several calibration points from a single calibration solution. The SV4-EC method is applied to inductively coupled plasma optical emission spectrometry (ICP-OES) and is based on gradient dilution taking place within the instrument's sample introduction tubing. Both the calibration solution and the samples are diluted by a blank solution containing an internal standard species. Forty-five dilution points are collected over time while the solutions are mixed. Instrument responses from the calibration solution are then plotted against those from the samples, and the slope of the calibration curve is used to determine the unknown analyte concentrations in the samples. The method is used to determine Ba, Co, Cr, Cu, Fe, Mn, Ni, V and Zn in coconut water, creek water, green tea, mouthwash, soft drink, vinegar, and vodka. Limits of detection are in the 0.0002–0.009 mg L−1 (n = 10) range, with precision on the order of 0.4 %–3 % RSD. Analyte percent recoveries from a 0.5 mg L−1 spike are in the ranges of 88.4 %–111 %, 88.9 %–111 %, and 88.0 %–111 % for EC, SV4-EC, and the internal-standard-corrected method (SV4-EC/Sc), respectively. No statistically significant difference is observed between EC and SV4-EC recoveries for any of the sample matrices evaluated. Comparable results between EC and SV4-EC were also found for the analysis of two certified reference materials, Bovine Liver and Oyster Tissue. Based on a single calibration solution, the SV4-EC method requires caution when preparing the calibration standard to minimize measurement bias.

The UCI Fluxtron: A versatile dynamic chamber and software system for biosphere–atmosphere exchange research

Here we present the UCI Fluxtron, a cost-effective multi-enclosure dynamic gas exchange system that provides an adequate level of control of the experimental conditions for investigating biosphere–atmosphere exchange of trace gases.We focus on the hardware and software used to monitor, control, and record the air flows, temperatures, and valve switching, and on the software that processes the collected data to calculate the exchange flux of trace gases.We provide the detailed list of commercial materials used and also the software code developed for the Fluxtron, so that similar dynamic enclosure systems can be quickly adopted by interested researchers. Furthermore, the two software components –Fluxtron Control and Fluxtron Process– work independently of each other, thus being highly adaptable for other experimental designs.Beyond plants, the same experimental setup can be applied to the study of trace gas exchange by animals, microbes, soil, or any materials that can be enclosed in a suitable container.

Mobile lab: A novel pathogen assay using the nucleic acid automatic assay system assisted by a self-contained microfluidic cassette and chitosan decorating magnetic particles

Microfluidic pathogen detection cartridges with integrated switching valves have gained significant attention. Traditionally, these microfluidic cartridges utilized magnetic beads for a “bind-wash-elute-reaction” protocol to extract DNA but often lacked PCR-based aerosol contamination validation and focused primarily on isothermal applications. There is room to improve these systems, such as using novel DNA extraction methods and integrating PCR as the gold standard. In this study, we developed chitosan-decorated magnetic (CDM) particles and incorporated them into a mass-produced, self-contained microfluidic cartridge for the first time. Our results demonstrated that the DNA can be efficiently enriched from the lysis buffer (pH 5) using 75 % degree of deacetylation and 1 % of chitosan-modified CDM particles (20 μL). The DNA extraction efficiency exceeded 90 %. The CDM particles enabled “in-situ PCR”, simplifying the on-chip detection process to a “bind-wash-reaction” protocol. Additionally, we developed a nucleic acid automatic assay system (NA3 system) featuring a fluid thermocycler, four-channel optical detection, magnet, microcontroller, and software. The entire assay, from sample preparation to detection, can be completed within approximately 60 minutes, simultaneously detecting 16 targets. The performance of the NA3 system was better than that of the pristine magnetic microparticles-based assay and the commercial magnetic beads kit-based assay. The linearity, specificity, multi-pathogen detection, and user-friendliness of the NA3 system were tested. We validated the NA3 system's performance in detecting food-borne and serum infectious pathogens, demonstrating its potential for use in resource-limited settings.

Development of a Two-Dimensional Liquid Chromatography Online Deproteinization Method for Determining Paclitaxel-Related Substances in a Paclitaxel Injection (Albumin-Bound)

To determine the paclitaxel-related substances in a paclitaxel injection (albumin-bound), it is necessary to remove human blood albumin from the sample via solid-phase extraction and subsequently perform high-performance liquid chromatography analysis. The pre-processing operation is complicated, the duration of analysis is long, and much human power and material resources are needed in the sample testing process. Thus, the purpose of this study was to develop a quick two-dimensional liquid chromatography method that requires less consumables and possesses high sensitivity. Samples were directly injected into one-dimensional solid-phase extraction columns to remove human blood albumin. Paclitaxel and its related substances in the solid-phase extraction columns were then eluted into two-dimensional analytical columns through valve switching technology. The sample pretreatment step can be omitted in this method, which allows for the analysis of paclitaxel and its related substances to be completed more quickly, within only 15 min, under the developed two-dimensional elution conditions. The established method had good linearity (R2 = 0.9994), limit of detection (0.25 μg·mL−1), limit of quantification (0.5 μg·mL−1), precision (RSD = 0.5%), and accuracy (102.53–107.97%).

Development of a Two-Dimensional Supercritical Fluid Chromatography System in Multiple Heart-Cutting Modes.

In this study, we present the development of a loop-based two-dimensional supercritical fluid system in multiple heart-cutting modes (mSFC-SFC), with diode-array and mass spectrometric detection. The instrument design was developed to be as simple as possible, based on a single SFC instrument, with the sole addition of three external 2-port 6-position valves. The objective was to achieve the most complete transfer of a peak from the first to the second dimension, whatever the composition of the mobile phase, i.e., whatever the proportion of carbon dioxide and methanol cosolvent along a wide gradient elution. Thanks to fine adjustment of the valve switching times, the first-dimension peaks were parked in 50 μL or 100 μL loops and later discharged to the second dimension. The interest of this instrument was then demonstrated with a sample application on a natural product: an extract of Citrus aurantium L. bark was analyzed, with a particular focus on chiral flavonoids, neohesperidin, and naringin. In this system, the first dimension was an achiral separation of the flavonoids, based on a polar diethylamine-bonded silica stationary phase (ACQUITY Torus DEA), while the second dimension used a stereoselective polysaccharide stationary phase (CHIRALPAK IB-3) to resolve flavonoid diastereomers. Excellent repeatability was demonstrated, with relative standard deviation values on retention times and peak areas all below 2%, together with excellent peak capacity and peak shapes (no distortion observed), making it possible to quantify diastereomers in the second-dimension separation. This good repeatability was also shown for the transfer rate between the two dimensions, which reached a value of 83%. Finally, transferring a compressible sample from the first to the second dimension is demonstrated to yield excellent performance, despite the large loop volume.

Online parameter identification based predictive pressure control for train electro-pneumatic braking systems with thermal effect

The electro-pneumatic braking system with ON/OFF solenoid valves has been widely used in trains due to its advantages and superiority. The undesirable impact of the thermal effect on the electro-pneumatic braking system leads to frequent valve switching, degradation of the pressure tracking performance and sometimes instability. This article presents an adaptive model predictive control approach to solve the pressure control problem under temperature uncertainty based on a switched unscented Kalman filter. First, a nonlinear switched dynamical model with the uncertain temperature parameter is derived for the electro-pneumatic braking system by comprehensively integrating its nonlinear, discontinuous dynamics and thermal effect. Using a switched unscented Kalman filter on the presented model of the system, the temperature parameter is accurately estimated to improve the model’s accuracy. Based on the corrected system model and the designed adaptive model predictive control method, the pressure tracking performance and the valves’ switchings of the electro-pneumatic braking system are improved, and the stability is guaranteed. The simulations and the experiments conducted for a braking system prototype confirm the performance validity of the proposed method.

Instrumental and theoretical advancements in pulsed elution-LC × LC: Investigation of pulse parameters and application to wastewater effluent

Due to the decoupling of the first (1D) and second (2D) dimension in pulsed elution-LC × LC (PE-LC × LC), method development is more flexible and straightforward compared to fast comprehensive LC × LC where the dependencies of key parameters between the two dimensions limits its flexibility. In this study we present a method for pulse generation, which is based on a switching valve alternating between one pump that delivers the gradient and a second pump that delivers low eluotrophic strength for the pause state. Consequently, the dwell volume of the system was circumvented and 7.5, and 3.75 times shorter pulse widths could be generated at flow rates of 0.2, and 0.4 mL/min with satisfactory accuracies between programmed and observed mobile phase composition (relative deviation of 6.0 %). We investigated how key parameters including pulse width and step height, 2D gradient time and flow rate affected the peak capacity in PE-LC × LC. The conditions yielding the highest peak capacity for the PE-LC × LC- high-resolution mass spectrometry (HRMS) system were applied to a wastewater effluent sample. The results were compared to a one dimensional (1D)-LC-HRMS chromatogram. The peak capacity increased with a factor 34 from 112 for the 1D-LC run to 3770 for PE-LC × LC-HRMS after correction for undersampling. The analysis time for PE-LC × LC-HRMS was 12.1 h compared to 67.5 min for the 1D-LC-HRMS run. The purity of the mass spectra improved for PE-LC × LC-HRMS by a factor 2.6 (p-value 3.3 × 10−6) and 2.0 (p-value 2.5 × 10−3) for the low and high collision energy trace compared to the 1D-LC-HRMS analysis. Furthermore, the signal-to-noise ratio (S/N) was 4.2 times higher (range: 0.06–56.7, p-value 3.8 × 10−2) compared to the 1D-LC-HRMS separation based on 42 identified compounds. The improvements in S/N were explained by the lower peak volume obtained in the PE-LC × LC-HRMS.

Development of vitamin K analysis method using column switching high-performance liquid chromatography method and analysis results of various food items for vitamin K content

In this study, we developed a column-switching high-performance liquid chromatography (HPLC) method with fluorescence detection for the analysis of vitamin K. Column-switching is accomplished by changing the direction of flow using a switching valve with a set time program. Using this method, three vitamin K, phylloquinone (PK), menaquinone-4 (MK-4), and menaquinone-7 (MK-7), were separated and identified with high sensitivity, and impurities were eliminated. This method was used to determine the vitamin K content in meat, fish meat, snails, bivalves, sea urchins, seaweeds, vegetables, tea, soy products, milk products, and supplements. The results showed that chicken showed the highest content of MK-4 (15.35 ± 0.35 μg/100 g), matcha showed the highest content of PK (3069.66±80.10 μg/100 g), and dried natto showed the highest content of MK-7 (3997.57±79.42 μg/100 g). This method can also be used to analyze vitamin K in supplements and pharmaceuticals. The results of this study revealed that different manufacturers add different types of vitamin K to their commercial supplements and infant formulas. The developed method provides highly reproducible and quantitative results and allows for the rapid analysis of the three vitamin K types. Thus, the method developed in this study may aid the sequential analysis of vitamin K in different samples to assess food nutrients.

Research and Practice on Implementing Segmented Production Technology of Horizontal Well during Extra-High Water Cut Stage with Bottom Water Reservoir

Bohai X oilfield has reached the extra-high water cut stage of more than 95%, dominated by the bottom water reservoir. The oilfield mainly adopts horizontal-well exploitation, with the characteristics of high difficulty and low success rate for well water plugging. To solve the above problem, the segmented production technology of horizontal wells was developed to guide oilfield applications and tap their potential. In the segmented design stage, the horizontal section is objectively segmented by drilling condition analysis, optimally based on drilling through interlayers or permeability discrepancy formation, simultaneously combined with the numerical simulation method. When implementing measures, annulus chemical packer materials are squeezed between segments to effectively inhibit the fluid flow between the open hole and the sand-packing screen pipe. Moreover, the packers are used to seal between segments to effectively restrain the flow between the screen and the central tube, achieving the establishment of compartments. In the production process, the valve switch on the central tube can be independently controlled by a remotely adjustable method to achieve optimal production. This segmented production technology was successfully tested for the first time in Bohai oilfield. Up to now, a total of six compartment measures have been implemented, remarkably decreasing water cut and increasing oil production for horizontal wells in the bottom water reservoir. This method does not require water testing, and the optimal production section can be chosen through segmented independent production, greatly improving the success rate of water-plugging measures for horizontal wells. This technology opens up a new mode for the efficient development of horizontal wells in bottom water reservoirs and is planned to be widely promoted and applied in similar oilfields.

Validation of An Efficient 2D-HPLC Method for The Determination of Pentazocine

Pentazocine is an opioid analgesic used to treat moderate to severe pains. The real analysis for the pharmaceutical products containing pentazocine is basically to ensure the correct dose and patient safety. This study developed and validated an improved high-performance liquid chromatography (HPLC) method in the selective and accurate quantification of pentazocine. Two-dimensional (2D) HPLC technique is employed to enhance the resolution and selectivity compared to conventional HPLC methods. The 2D-HPLC instrumentation consists of two C18 columns coupling with a switching valve to capture fractions from the first column, which is analyzed in the second column. The mobile phase was optimized to 45% acetonitrile and 55% water with 0.1% phosphoric acid. The method was validated in the International Conference on Harmonization guidelines and shows excellent linearity (R2=0.998), limit of detection of 1.58 μg/L, accuracy of 97.70–102.50%, and precision by relative standard deviation (RSD) of 1.02–4.20%. Selectivity was verified in resolving pentazocine from paracetamol, caffeine, ibuprofen, and oxycodone in laboratory mixtures. The utility of the 2D-HPLC method was demonstrated by accurate quantification of pentazocine in pharmaceutical injections and tablets unaffected in excipients. This research provides a rich validating technique to enhance the quality control testing of pharmaceuticals containing pentazocine.

Characteristics analysis and nonlinear control of a digital hydraulic pressure tracking system for high-speed helicopter wet friction clutch

The reliability and control precision of the engagement and disengagement of wet friction clutch are crucial to the transmission of high-speed helicopters. In contrast to the traditional proportional hydraulic system, the digital hydraulic system provides a viable solution due to the use of several fast switching valves (FSVs). In this research, a digital hydraulic pressure tracking system using two fast switching valve arrays (DHPTS-FSVA) is proposed and its nonlinear model is established. First, the static and dynamic characteristics of the DHPTS-FSVA are deeply analyzed by virtue of the half-bridge resistance theory. Moreover, a novel pressure control strategy is proposed, which consists of nonlinear adaptive control method, differential pulse width modulation (PWM) with pressure compensation, and logic allocation strategy of PWM duty ratio. Finally, comparative simulation and experimental results indicate that the maximum, average, and standard deviation of the errors are reduced by at least 16.1%, 45.1%, and 39.5%, respectively, at the tracking frequencies of 1 and 2 Hz, which proves that the proposed controller exhibits better tracking performance at low frequencies.

An Improved Zero-Flowrate Switching Control Method to Reduce Switching Losses in a Hydraulic Actuator

Hydraulic switching actuators are high-efficiency, fast response, and low-cost solutions for hydraulic control systems. One of the challenging problems is throttling losses during valve transitions. Previously, the authors proposed a zero-flowrate switching method to reduce the throttling energy loss of the switching valve, where a hydraulic resonator is applied to make the flowrates through the lines approaching zero before the valves are switched off. The major challenge of this approach is fast switching valves whose transition times are less than 2 ms. In this paper, an improved zero-flowrate switching method is presented. It utilizes the capacity with independent inlet/outlet ports to regulate flowrates through the lines. Models of capacity applied in a simple line with different pressure signals are developed to explore characteristics of the capacity, based on which a complete actuation system is developed. In the complete model, resistance and inductance are optimized to achieve the desired flowrate response. The improved zero-flowrate switching method reduces throttling energy losses by 99.945% compared to a hard switching system. The simulation results demonstrated that the improved zero-flowrate switching method performs as expected in the design condition. A capacity with proper volume is able to regulate flowrates through all the lines to zero, with the help of appropriate resistance and inductance. Compared to the previous zero-flowrate switching method, the novel strategy allows slower switching valves applied in hydraulic actuation systems and achieves better efficiency performance. This research paves a new avenue for reducing throttling energy losses and improves system efficiency in hydraulic switching actuators, as well as most of the hydraulic switch-mode circuits.

Development of a rapid screening method utilizing 2D LC for effect-directed analysis in the identification of environmental toxicants

Effect-directed analysis (EDA) is a crucial tool in environmental toxicology, effectively integrating toxicity testing with chemical analysis. The conventional EDA approach, however, presents challenges such as significant solvent consumption, extended analysis time, labor intensity, and potential contamination risks. In response, we introduce an innovative alternative to the conventional EDA. This method utilizes the MTT bioassay and online two-dimensional liquid chromatography (2D LC) coupled with high-resolution mass spectrometry (HR-MS), significantly reducing the fractionation steps and leveraging the enhanced sensitivity of the bioassay and automated chemical analysis. In the chemical analysis phase, a switching valve interface is employed for comprehensive analysis. We tested the performance of both the conventional and our online 2D LC-based methods using a household product. Both methods identified the same number of toxicants in the sample. Our alternative EDA is 22.5 times faster than the conventional method, fully automated, and substantially reduces solvent consumption. This novel approach offers ease, cost-effectiveness, and represents a paradigm shift in EDA methodologies. By integrating a sensitive bioassay with online 2D LC, it not only enhances efficiency but also addresses the challenges associated with traditional methods, marking a significant advancement in environmental toxicology research.

On-line temperature-responsive restricted access material of sample preparation technique coupling with liquid chromatography for detection of tetracycline residues in milk

Effort of sample preparation has been working towards the automation and improvement of accuracy. Development of on-line sample preparation coupled with liquid chromatography (LC) is a promising way. In this study, an on-line extraction-LC automated analysis was proposed based on a temperature-sensitive restricted access material (RAM) for the determination of tetracycline residues (TCs) in milk. The RAM was synthesized using silica as substrate by the two-step surface initiated-atom transfer polymerization (SI-ATRP), styrene (St), sodium 4-vinylbenzenesulfonate (Nass) and a lower critical solution temperature (LCST)-responsive n-vinylcaprolactam (VCl) were conjugated to fabricate multiple interaction-adsorption sites of P(St-co-Nass-co-VCl) on silica interior, while an upper critical solution temperature (UCST)-responsive sulfobetaine methacrylate (SBMA) was then block polymerized to form zwitterionic exclusion sites on exterior. Thereafter, the RAM was packed as extraction column to be fixed into LC ahead of C18 analytical column, establishing automatic analysis by rotation of switching valve. In conjunction with LCST and UCST dual-responsive properties to adjust the hydrophobic-hydrophilic transition of the grafted P(St-co-Nass-co-VCl)-b-PSBMA chains, the RAM column acquires the best extraction of TCs and meanwhile the furthest removal of proteins at about 30 ℃ of column temperature. And using the proposed automatic analysis for monitoring of TCs in milk, a wide linearity (20–900 ng mL−1), low limit of detection (1.0 ng mL−1) and limit of quantification (2.5 ng mL−1) as well as good inter-day (<3.9 % RSD) and intra-day precision (<4.8 % RSD) with satisfactory recoveries (97.2–101.9 %) show the superior efficiency. It is believed that the introduction of temperature-sensitive RAM to construct on-line extraction is a powerful tool for detecting trace substances in scientific analyses.