Valve Module Research Articles

Design and Experiment of a Reconfigurable Bypass Downlink Surface Equipment for Transmitting the Surface Information to Deep Well

Abstract: In order to achieve the transmission of the control information from the surface to the downhole in the deep well during drilling, a design method of a new downlink surface equipment for generating negative pulse signals is presented in this paper. The equipment uses adjustable throttle control valve and pressure drop module (PDM) to realize bypass flow control. The PDM uses multistage variable nozzles to reduce drilling fluid pressure and meet drilling requirements under different pressure and flow rates. Design theory of the downlink surface equipment is established, and a specific design instance is given according to actual drilling conditions. Both laboratory and field experimental results verify the correctness of the proposed design method. The research results show that the design equipment can meet the needs of the transmission of the surface information, and the downlink transmission rate can reach at least one-bit data per 8 sec. The maximum pressure drop is realized by the PDM and the pressure drop at the control valve will be reduced according to drilling demand, the fluid velocity in the equipment is reduced as much as possible, the erosion of the drilling fluid to the equipment is reduced, and the service life can be improved effectively.

Characterization of two-dimensional cartridge type bidirectional proportional throttle valve

A novel bidirectional proportional throttle valve with a two-dimensional (2D) plug-in structure is proposed in this paper. The valve integrates the 2D valve module and the logic valve into one component, with high integration degree, response speed, and control accuracy. The mathematical model of the 2D valve module is established based on the continuity equation of flow and kinematic equation, and the stability criterion of the valve is established. The effects of the inclination angle, width, and initial overlapping height of the oblique slot and rectangular slot on the dynamic response of the valve are explored by AMESim simulation, and appropriate structural parameters are selected to design and manufacture the prototype valve. A dedicated test bench is built, and the feasibility of the valve design is verified by testing the valve under different system pressures and different load variations. The experimental results show that, at a system pressure of 21 MPa, the prototype valve has a flow rate of 53.5 L min−1, a hysteresis of 0.8%, a linearity of 5%, and a step response time of 6.5 ms. When the analog valve opening is changed by inputting 0.1 Hz signals with different waveforms under different system pressures, the maximum fluctuation of the main spool displacement is less than 1 μm, and the maximum stabilization time does not exceed 110 ms.

Evaluating the suitability of a new telemetric capacitance-based measurement system for real-time application in irrigation and fertilization management

The suitability of a new wireless smart farming system for controlling irrigation and fertilization of horticultural plants was assessed in the study. The system (name: AGREUS®) includes sensors (soil moisture, salinity, weather data), executive modules (valve modules), and an application available on the web portal (accessed through computers and mobile devices). The studies were performed under laboratory and field conditions. Laboratory tests included appraisal of the precision of soil moisture and salinity measurements carried out with the soil probe (comparison with the results obtained by laboratory methods). Operational tests were conducted in field trials. In these trials, assessment of the possibility of practical control of irrigation and monitoring soil salinity was performed in an apple orchard. The conducted analyses have shown the usefulness of the system, not only for automatic control of irrigation but also for making decisions about the necessity to fertilize plants. The system enables continuous monitoring of changes in soil moisture and salinity, including the migration of minerals across the soil profile (using a probe with several measuring elements) as a result of the applied irrigation or rainfall. The system allows for automatic application of irrigation or fertigation depending on the adopted soil moisture and salinity thresholds. However, the tests showed that a salinity index calculated by the system does not directly correspond to the salinity values determined by laboratory methods. For this reason individual interpretation and determination of optimal ranges for plants is required.

Internet of things and agent-based system to improve water use efficiency in collective irrigation

The efficient management of water resources is a major issue in the field of sustainable development. Several models of solving this problem can be found in the literature, especially in the agricultural sector which represents the main consumer through irrigation. Therefore, Irrigation management is an important and innovative field that has been the subject of several types of research and studies to deal with the different activities, behaviors, and conflicts between the different users. This article introduces an intelligent irrigation system based on smart sensors that can be used moderately and economically to monitor farms by integrating some connected electronic devices and other advantageous instruments widely used in the field of IoT, it determines the water requirement of each farm according to the water loss due to the process of evapotranspiration. The water requirement is calculated from data collected from a series of sensors installed in the plantation farm. This project focuses on smart irrigation based on IoT and agent technology, it can be used by farmer associations whose endowments and irrigation planning are defined according to the need and quantity of water available in the rural municipality. The system includes a microcontroller with the integration of sensors, actuators, and valve modules where each node serves as an IoT device. Environmental parameters are monitored directly through a multi-agent system that facilitates the control of each node and the configuration of irrigation parameters. The amount of water calculated for irrigation is based on the Penman model for calculating the daily evapotranspiration baseline. Compared to the conventional irrigation method, it is expected that the proposed irrigation model would contribute to saving water use and distributing it impartially without compromising its production.

Autonomous Farming Robot

Pakistan's farming industry has significant problems, including low yields and inefficient use of essential resources such as water, fertilizer, and pesticides. In this era of modern technology, conventional methods of farming are unable to fulfil the agricultural demands in its respective time. Smart Farming is developing towards digitalized and data-driven operations, advanced decision support systems, smart analyses, and planning, among others. Agriculture is a perfect niche for innovations in the sphere of robotics. In this research microcontroller-based Autonomous Farming Robot is developed, that would allow farmers to use resources such as water and seeds more effectively and efficiently. Robot structure is modeled in AutoCAD software and has been constructed using wood and steel pipes. Further, different components like sensors, stepper motors and its drivers, DC motor and its driver, solenoid valve, water pump and relay module have been mounted on the robot structure and interfaced with ARM microcontroller. Three-dimensional movement inside the robot is added using stepper motor, so that robot can cover a large area and thus speed of work can be enhanced. In addition, a Web based Graphical User Interface (GUI) is designed using webserver controller, which provides a graphical assistance to users so that they can monitor the sensor data and operate the robot wirelessly with their own desired strategy of plantation. The system has been tested using coriander seeds on the soil bed and from the experimental results, it is found that designed system can execute complex tasks such as precise distribution of seeds, soil bed preparation, watering and monitoring agricultural parameters like temperature, humidity, and moisture appropriately.

Valve-based comprehensive two-dimensional gas chromatography with quadrupole mass spectrometry detection using a porous layer open tubular column in the first dimension

A comprehensive two-dimensional gas chromatography instrument with quadrupole mass spectrometry (GC×GC-qMS) is developed and evaluated, by retrofitting a commercial GC-qMS instrument with a high temperature diaphragm valve (HT-DV) modulator. A porous layer open tubular (PLOT) column in the first dimension (1D), and a more polar wall coated open tubular (WCOT) column in the second dimension (2D) were used. The HT-DV can modulate analytes of any volatility and the combination of the PLOT and WCOT columns provides ample separation selectivity for samples containing an extended range of volatility from highly volatile analytes to analytes of more moderate volatility. In addition to instrument development, we describe data visualization considerations when upgrading from GC-qMS to GC×GC-qMS. Unlike time-of-flight mass spectrometry (TOFMS), the mass spectrum cycle time for qMS (defined as the sum of scan time and interscan delay) is a linear function of the range of mass channels (m/z) analyzed. If the cycle time does not divide evenly into the modulation period, PM, visual distortions will appear in the GC×GC chromatogram. We present two approaches to address this GC×GC chromatogram distortion issue. The first method does not require post-run computations; however, care must be taken in selecting an appropriate mass range to minimize the visual distortion issue. A half of the modulation period of total shift in the 2D separations with a PM of 2 s was determined tolerable for a 15 min separation, with 44 mass ranges (and their accompanying scan rate) deemed suitable out of 350 possible mass ranges. Also, a computational “resampling” method, which can be used to correct any qMS scan rate used was implemented. Figures-of-merit for the HT-DV modulated GC×GC-qMS instrument were also examined. Reproducible peak height (average RSDheight = 9.2%, s = 3.5%) and areas (average RSDarea = 9.3%, s = 2.8%) were obtained with low LODs (average LOD = 4.2 mg/L, s = 2.5 mg/L).

A 3D-Printed Standardized Modular Microfluidic System for Droplet Generation

Droplet-based microfluidics has a variety of applications, such as material synthesis and single-cell analysis. In this paper, we propose a modular microfluidic system using projection micro-stereolithography three-dimensional (3D) printing technology for droplet generation. All modules are designed using a standard cubic structure with a specific leakage-free connection interface. Versatile droplets, including single droplets, alternating droplets, merged droplets, and Janus particles, have been successfully produced. The droplet size and the generation rate can be flexibly controlled by adjusting the flow rates. The influence of the flow rate fraction between the discrete phase and the continuous phase over the generation of the alternating and merged droplets is discussed. Furthermore, the 'UV curing' module can be employed to solidify the generated droplets to avoid coalescence and fix the status of the Janus particles. The proposed modular droplet generators are promising candidates for various chemical and biological applications, such as single-cell incubation, screening of protein crystallization conditions, synthesis of nanoparticles, and gene delivery. In addition, we envision that more functional modules, e.g., valve, microreactor, and detection modules, could be developed, and the 3D standardized modular microfluidics could be further applied to other complex systems, i.e., concentration gradient generators and clinical diagnostic systems.

Finger-powered cell-sorting microsystem chip for cancer-study applications

There is a great demand for sorting applications related to bio/medical cells, such as sorting tumor-infiltrating immune cells (TIICs) from solid tumors. However, the complex operating process, bulky medical instruments, and skilled people become obstacles. We reported an integrated finger-powered cell-sorting microsystem chip that demonstrated TIICs separation from a suspension of a solid tumor. The chip contains the functions of self-powered supply by a finger pump, staining cells by micromixers, cell sorting by deterministic lateral displacement (DLD), and cell-counting by combining an external microscope. The finger-powered microfluidic actuator integrated with the additional valve module handles different fluids and effectively prevents backflow as desired. The integrated micromixer effectively mixes the stain and cell sample in the design ratio. Then, the stained cell solution and the buffer solution are driven into the DLD area by the same pump module. From the four-stage continuous DLD sorting area, the non-target cells are dispersedly shifted. We demonstrated the finger-powered cell-sorting microsystem chip by using the suspension of solid tumor from CT26-bearing BALB/c mouse as a sample. The high purity and recovery rate of 97.23 % and 88.74 % were characterized by finishing the whole function operation in less than a minute.

Numerical Simulation of Converter Station Fire: A Study focus on the Fire Hazard of Valve Tower

The fire hazard of a valve tower in converter station fires were investigated by using the Fire Dynamics Simulator (FDS). The 2 m2, 5 m2 and 10 m2 transformer oil pool fires with the calculated heat release rate (HRR) of 2.02, 6.23 and 13.78 MW were considered in the simulations, and the smoke propagation process, smoke temperature and visibility were mainly concerned. The results showed that the whole valve tower was immersed in the fire smoke at about 600 s in 2 m2 fire condition, and the maximum temperature rise inside the valve hall was about 20ºC. In the 5 m2 fire condition, the smoke layer height descended to the bottom of the valve tower at about 300 s, and the visibility around the valve modules was lower than 5 m at about 450 s. The maximum smoke temperature inside the valve hall was over 60ºC, and the temperature of smoke around the valve modules ranged from 43 to 52ºC. In the 10 m2 fire condition, the valve tower was immersed in the fire smoke at about 210 s, and the visibility around the valve modules was lower than 5 m at about 300 s. The smoke temperature beneath the ceiling of the valve hall was over 100ºC, and the temperature at the height of valve towers ranged from 65 to 80ºC. It was observed that the larger the fire size was, the higher the fire hazard of the valve tower would be found. In the 5 m2 and 10 m2 pool fire conditions, the thermal damage to the valve tower was non-negligible. The normal operation of the electrical components in the valve tower might be affected, and the failure of electrical components might be occurred.

Reservoir Stimulation Technique Combines Radial Drilling Technology With Acid Jetting

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 202661, “Combination of Radial Drilling Technology With Acid Jetting: New Approach in Carbonate Reservoir Stimulation,” by Ayrat Bashirov, Ilya Lyagov, and Ilya Galas, Perfobur, prepared for the 2020 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, held virtually 9–12 November. The paper has not been peer reviewed. The complete paper describes an approach to stimulate carbonate formations with bedding water or a gas cap. The technique is a combination of acid jetting and a radial drilling technology that uses mechanical radial drilling with a slim mud motor. The primary advantages of the technology include controlled trajectory and the possibility of re-entry into channels. The novelty of the technology is in its ability to deploy acids in the rock far away from the wellbore through the mechanically drilled holes with known depths and azimuths. Reservoir Description The mature field is in central Russia in the Republic of Bashkortostan. The field contains both sandstone and carbonate reservoirs. Oil depth is from 780 to 1830 m. Six reservoirs are in development. This study concentrates on projects in a carbonate formation that is a substage of the early Pennsylvanian Period. This formation is highly heterogeneous with closely underlying water. Permeability of the reservoir is approximately 43 md; reservoir pressure is 1,000 psi, and oil density is 0.891 g/cm3. Two adjacent well candidates with identical reservoir properties were selected for the study, with a distance between wells of approximately 136 m. Net oil thickness in Well A is 4.4 m and 3 m in Well B. Mechanical Radial Drilling Technology The technology described by the authors uses mechanical radial drilling with a slim mud motor. The technology allows the drilling of a network of radial channels up to 15 m long with up to four channels of different trajectories on one level. The technical system features a modular construction for ease of assembly at the wellhead area and increased operational efficiency. The main elements of the technical system include the following: - Pipe pusher connected at the top with an overflow valve module and, at the bottom, with a guiding device connected by means of a hydraulic pusher - Flexible pipe assembly with a small (nonstandard) sectional mud motor - Drilling bit (milling cutter for window cutting) - Special whipstock and an anchor module with an orienting funnel connected from below to the pipe frame

Luer-lock valve: A pre-fabricated pneumatic valve for 3D printed microfluidic automation.

3D printed microfluidic devices are made of stiff and easy-to-fatigue materials and hence are difficult to have robust pneumatic valves. In this work, we describe a type of prefabricated polydimethylsiloxane (PDMS) valves, named the "Luer-lock" valve, which can be incorporated in 3D printed microfluidic devices utilizing the Luer-lock mechanism. Luer-lock design has been adopted for fluidic connections worldwide; it is facile, reliable, and inexpensive. To take advantage of the Luer-lock design, we added "valve ports" to our 3D printed microfluidic devices; prefabricated PDMS valve modules could be embedded into these valve ports, in a leak-free manner, by screwing tight the Luer-locks. In the experiment, we succeeded in fabricating pneumatic valves with a footprint diameter of 0.8 mm and verified the functionality of these valves with a shut-off pressure of 140 mbar and a maximal switching frequency of ∼1 Hz. As a demonstration, we show the serial encoding of core-shell hydrogel microfibers using the Luer-lock valves. Since the Luer-lock valves can be mass-produced and the CAD model of Luer-locks can be easily distributed, we believe that our approach has the potential to be easily adopted by researchers around the globe.

AUTOMATIC CONTROL SYSTEM CHARGING FUEL TANKS AND MONITORING TEMPERATURES USING PLC

Fuel oil reservoir filling and temperature monitoring can be done automatically using Omron PLC type CP1E N20DR-D 20 I / O with a ladder diagram program designed with the CX-Programmer computer application. And the input used in the form of a level sensor module and temperature sensor, while for the output in the form of a selenoid valve, 3 phase AC motor and buzzer. The level sensor functions to find out the high and low levels of the oil surface in the tank and the output is in the form of a selenoid valve module that functions as a valve for filling full oil, while the motor pump functions as a distributor fuell oil. And the temperature sensor module serves to detect the high and low temperatures or safe temperatures that are allowed at the time of distribution of fuel to the Truck fuel oil reservoir, while the output is in the form of a buzzer that serves as a source of sound or alarm markers. Based on the calculation results obtained that the error presentation of the two selenoid has the same value of 0%, while the level sensor, thermal sensor, and pump motor each have a presentation value that is almost the same with each other, so that the automatic control system of filling the fuel oil reservoir and monitorn the temperature can run smoothly.

The Use of Acoustic Emission Elastic Waves for Diagnosing High Pressure Mud Pumps Used on Drilling Rigs

Although mud pumps are vital components of a drilling rig, their failures are frequent. The identification of technical condition of these high-pressure piston pumps is difficult. There are no reliable criteria for the assessment of mud pump condition. In this paper, faults of the pump valve module are identified by means of acoustic emission (AE) signals. The characteristics of these signals are extracted by wavelet packet signal processing. This method has been verified by experiments conducted on a NOV (National Oilwell Varco) -made triplex 14-P-220 mud pump (mounted in the drillship). The results show that the wavelet packet signal processing method can effectively extract the frequency band energy eigenvalues of the signals. Besides, some operational problems associated with high pressure piston mud pumps are presented. A non-invasive method for diagnosing the technical condition of such pumps is being developed at the Maritime University of Szczecin.

MANUFAKTUR ALAT PERAGA ALIRAN FLUIDA DI DALAM PIPA MODUL TAMBAHAN

Abstract. Fluid mechanics is one of the courses that discusses the flow of fluid in a pipe. The material in it includes knowledge of energy flow losses that occur in the piping system. This flow loss, will later show the piping system performance. In lecture material, the term flow loss is known as the Head Loss. The fluid flow props in this pipe are parallel studies with basic module research. In this study, making a more varied valve module and additional measuring devices on the Headloss visual aid in the hope of helping and making effective learning of fluid mechanics in mechanical laboratories. These modules are called additional modules.Keywords: Props, Fluid Flow in the Pipe, Head Loss, Ball velve.

A simple saliency detection approach via automatic top-down feature fusion

It is widely accepted that the top sides of convolutional neural networks (CNNs) convey high-level semantic features, and the bottom sides contain low-level details. Therefore, most of recent salient object detection methods aim at designing effective fusion strategies for side-output features. Although significant progress has been achieved in this direction, the network architectures become more and more complex, which will make the future improvement difficult and heavily engineered. Moreover, the manually designed fusion strategies would be sub-optimal due to the large search space of possible solutions. To address above problems, we propose an Automatic Top-Down Fusion (ATDF) method, in which the global information at the top sides are flowed into bottom sides to guide the learning of low layers. We design a novel valve module and add it at each side to control the coarse semantic information flowed into a specific bottom side. Through these valve modules, each bottom side at the top-down pathway is expected to receive necessary top information. We also design a generator to improve the prediction capability of fused deep features for saliency detection. We perform extensive experiments to demonstrate that ATDF is simple yet effective and thus opens a new path for saliency detection.

Noise source modifications to enhance performance of an acoustic modulation system

The ability to simulate extreme flight environments of aerospace structures, such as high-intensity thermal acoustic loading, is achieved through the use of a progressive wave tube facility. This valve modulation system, used to create the random acoustic wave, behaves like an electromagnetically driven spring-mass system that uses electro-pneumatic, vibrating-vane air valves as the noise source. Each valve requires an electrical input and reaction with a magnetic field to generate the force necessary to overcome the spring stiffness of the outer portion of the valve. This force, driven by a current carrying wire, opens and closes the modulation slots, creating airflow pressure pulses necessary to generate higher sound pressure levels. Several physical characteristics of the noise source can be modified to generate a higher force on the spring section of the valve. This work documents the increase in the overall sound pressure level output of the noise source by varying the cross-sectional area and gage size of the current carrying wire, documenting performance of materials which strengthen the magnetic field, and by comparing the frequency about which the narrow band drive signal was centered. Based on the results of these comparisons, an optimal combination of physical characteristics will be discussed.The ability to simulate extreme flight environments of aerospace structures, such as high-intensity thermal acoustic loading, is achieved through the use of a progressive wave tube facility. This valve modulation system, used to create the random acoustic wave, behaves like an electromagnetically driven spring-mass system that uses electro-pneumatic, vibrating-vane air valves as the noise source. Each valve requires an electrical input and reaction with a magnetic field to generate the force necessary to overcome the spring stiffness of the outer portion of the valve. This force, driven by a current carrying wire, opens and closes the modulation slots, creating airflow pressure pulses necessary to generate higher sound pressure levels. Several physical characteristics of the noise source can be modified to generate a higher force on the spring section of the valve. This work documents the increase in the overall sound pressure level output of the noise source by varying the cross-sectional area and gage s...

Assessment of efficiency of electric drive of stop valves

The operation features of the stop valve electric drive are analyzed. It is found that the drive of stop valves, implemented on the basis of induction motors, is characterized by low energy efficiency. For the purposeful improvement of the energy efficiency of the electric drive, a method is developed for estimating the energy efficiency of the valve module. The need to develop the method is due to the fact that energy efficiency estimates based on international standards are valid for steady-state operating conditions, provided that the time of transient processes is neglected. Unlike traditional types of actuators, the stop valve actuator is characterized by low speeds. The use of mechanical gearboxes does not significantly reduce the drive speed, so you have to carry out pulse control of the engine or switch to a gearless drive. The efficiency of alternative engine types is estimated using the proposed method, which is based on valve positioning modeling. The trajectory of movement is formed in accordance with the control pulses applied to the windings of the motor, which is part of the mechatronic module. Testing of the method is carried out on the basis of the passport data of the 120 W AIR56A4 induction motor, which is part of a serial single-turn mechatronic module. For comparison of energy indicators, a 3-phase synchronous rolling rotor motor was chosen, whose parameters of the stator winding are similar to those of the AIR56A4 motor winding. Comparison of energy efficiency estimates showed the advantage and prospects of using gearless synchronous motors in the valve drive. The developed models allow to investigate and optimize the characteristics of the electric drive based on the tested engines, as well as to formulate the requirements for the engine design and technological parameters based on the obtained energy efficiency estimates. The proposed method of energy efficiency assessment is the basis for the implementation of a set of technical tools to assess the drive energy efficiency in real industrial conditions when performing a specific technological task.

A high efficiency electric heater based on dual-helical tube and screw-tape for instant water heating

Waste of natural water resources is a serious worldwide challenge, especially in many water shortage countries. There is an urgent and widely known problem that cold-water needs to be released from the faucet before people need warm or hot water. Therefore, there is urgent need for a feasible and effective solution to tackle this problem. In this paper, we proposed a novel instant water-heater based on a dual-helical tube and screw-tape for application in faucets. The proposed water-heater includes four main parts: a control valve module, a cavity structure module, a heating module, and an electronic control module. The heating module is comprised of a dual-helical tube and screw-tape. The dual-helical tube increases the heating area, resulting in uniform heating. The screw-tape possesses a profitable characteristic in that it can make fluid tangential flow and lower the cross-sectional area of the fluid. Based on this advantage, the core region and wall region fluids are mixed, which significantly enhances the heat-transfer rate. The effects of a dual-helical tube and screw-tape with different helical pitch are examined. The experimental results are compared with those obtained using a helical tube/dual-helical tube alone. A 59.6% efficiency improvement is achieved comparing the dual-helical tube and screw-tape with the single helical tube, which suggests the proposed instant electric water-heater is highly efficient and energy saving.

Ultrafast separations via pulse flow valve modulation to enable high peak capacity multidimensional gas chromatography

Ultrafast modulation with a modulation period PM ≥ 50ms via a pulse flow valve is demonstrated for comprehensive two-dimensional gas chromatography (GC×GC) and comprehensive three-dimensional (3D) gas chromatography (GC3). Significant increases in peak capacity and peak capacity production are achieved for GC×GC and GC3 relative to previous studies due to using pulse flow valve modulation. Due to the nature of the “partial” modulation process, the separation dimension following pulse flow valve modulation is not a traditional chromatogram, rather requires data processing to convert the data to expose the encoded chromatographic information, producing “apparent” chromatographic peaks. In the GC×GC mode, a 115-component test mixture was evaluated using a PM of 500ms, creating an apparent 2D peak width-at-base 2W with an average of 25ms, producing a 2nc of 20. Based on the average 1W of 1.0s for the 6min first dimension 1D separation, an ideal peak capacity nc,2D of 7200 is achieved (1,200/min peak production). For a high-speed GC×GC separation (30s run), a PM of 75ms produced apparent 2W of 8ms, ideal for the third dimension of a GC3 instrument. Using the knowledge gained from this high-speed GC×GC experiment, the pulse flow valve was implemented as the second modulator in GC3. Three samples were evaluated in the GC3 mode: a simple mixture containing 18 compounds (to illustrate basic concepts), the 115-component test mixture (to determine peak capacity figures-of-merit), and a diesel spiked with 8 polar compounds (to illustrate chemical selectivity benefits of GC3). For the 115-component test mixture with a 1PM of 1.2s and a 2PM of 60ms, average 1W of 3.2s, 2W of 130ms, and apparent 3W of 13ms were produced, resulting in a 1nc of 210, 2nc of 9.2, and 3nc of 5, respectively. Hence, an ideal peak capacity, nc,3D of ∼10,000 for GC3 was achieved for the 11min 1D separation window of the 115-component test mixture.

A comprehensive two-dimensional gas chromatography valve modulation method using hold-release primary column flow for long secondary separation time with 100% transfer

A valve modulator with a hold-release primary column flow method has been proposed. This method uses a valve plumbed so that the head and tail of the primary column are connected during the secondary separation, to reverse, slow down, and finally stop the primary column flow. This keeps the sample in the primary column longer, gaining more time for secondary separation. Applying this method, a 60-second secondary retention time with 100% transfer, 133 ms secondary peak width at base, and no primary peak profile loss has been achieved. A standard sample with 19 compounds in 3 groups has been tested. The relative standard deviations for the retention time of this standard mixture are <0.26% for primary dimension and <0.94% for secondary dimension. A gasoline sample analysis with 5, 15, and 30-meter-long secondary columns has been demonstrated. With the secondary column length increase, the secondary separation has greatly improved even though the total run time increases to 45, 110, and 120 min and the toluene primary peak width at base increases to 0.51, 1.81, and 1.85 min respectively. A diesel samplerun by this method has also been demonstrated.