Liquid Level Detection Research Articles

Research of Drilling Gas Kick and Blowout Characteristic Based on The Volume of Fluid Model

The accident of drilling blowout out of control is a serious drilling accident. One of the measures that prevent this accident is detecting gas kick early. Mud pool liquid level method is one of the most widely used methods. But, due to the drilling bell mouth is exposed to the atmosphere, drilling fluid in the return pipe flow is not a full pipe flow but a free flow. When the gas kick was tiny, the change of mud pool level is unobvious and Liquid level detection device could not measure the level changes effectually. Drilling fluid return flow can’t be measured, and the error was so great that can’t detect the gas kick early. Air and drilling fluid (non-Newtonian fluid) were taken as mediums, to simulate the drilling fluid liquid level when drilling fluid return flow changed based on the Volume of Fluid multiphase flow model, then the characteristic of liquid level change in the return pipeline was analyzed with different gas rate in drilling fluid. It concluded that the liquid level in the bell mouth was changing obviously, when the drilling fluid has been changed with none gas. Give a suggest that Liquid level detection should be installed on the bell mouth in drilling fluid return pipe in order to find gas kick more accurately and effectively earlier. The gas kick rate has a great impact on the stability of the drilling fluid liquid level in the return pipeline.

The System of Liquid Level Detection

The design is a ultrasonic level meter based on the PIC18F4520 micro chip. This ultrasonic level meter can be achieved in data is not lost when the power is down, making multi-function button to change the value, accurate measurement of liquid level. Closed loop fixed gain amplifier and the echo peak calibration signal amplification technology eliminates the phase shift error and the amplitude fluctuation error of the method, and digital potentiometers to achieve the system's automatic gain control, improve the quality of the echo signal. The effect of design is good, especially in sewage treatment, and oil storage tank system that can not contact measuring system have a strong value in use.

Hoist Lubricating Oil Pressure and Liquid Level Detection

This article describes the structure, working principle and technical parameters of the lubricant oil pressure and liquid level indicating alarm system of the mine hoist. In order to send signals to the main control room displaying pressure and liquid level， the use of digital circuit-designed smart modular pressure transmitter, level transmitter, with the light beam warning indicator, display the fluid pressure and fluid level signal in the main control room, the limit alarm, and the upper and lower limit settings.

Dynamic behavior of resonant piezoelectric cantilever as liquid level detection sensor

Resonant Piezoelectric-excited Millimeter-sized Cantilevers (PEMC), has attracted many researchers’ interest in the applications such as liquid level and density sensing. As in these applications, the PEMC are partially immersed in liquid, an appropriate analytical model is needed to predict the dynamic behavior of these devices. In this work, a PEMC has been fabricated for liquid level sensing. An analytical model based on Euler–Bernoulli beam theory and energy method is developed and applied to evaluate the performance of this device with respect to different tip immersion depth. To validate the proposed model, the theoretical results are compared with the experimental results for the tip immersion depth from 5 to 15 mm in water. The simulation results are in almost good agreement with experimental data. Using the proposed model, the two key parameters of sensor performance: sensitivity and working range have been examined for different mode shapes of PEMC vibration.

An electromagnetic resonance circuit for liquid level detection

Electromagnetic resonators are often used to detect foreign materials. Here we present a simple experiment for the measurement of liquid level. The resonator, consisting of a coil and a capacitor, is brought to resonance by an external magnetic field source, and the corresponding resonance frequency is determined using Fourier analysis combined with nonlinear curve-fitting. A medium inside the resonator alters its resonance frequency, depending on the liquid level of the medium.

The design of a wireless flexible capacitive sensor detection system to detect liquid level in plastic bag intravenous drip sets

Intravenous (IV) therapy is extensively used in hospital treatments for infusion of liquid substances directly into a vein. When the medicine has been fully dispensed, an air embolism can be occurred since air in the IV drip bag could enter into the patient’s vein, which is hazardous to the patient’s safety. To prevent this situation, in this paper, design of a wireless detection system using flexible capacitive sensor to detect liquid level of IV drip set is proposed. In the conducted research, a simulation model of capacitive sensor technology was shown by using finite elements analysis (FEA), and its proper geometrical dimension of the capacitive sensor was found out. The studied capacitive sensor was used in this proposed wireless detection system. The system consisted of a wireless capacitance detector for liquid level detection, and a wireless receiver for acquiring the measuring data in another place. The flexible capacitive sensor was fixed on one side of the wireless capacitance detector, and the wireless capacitance detector was placed at the bottom surface of the plastic IV drip bag to measure the changing level of the capacitance. The measured signal from flexible capacitive sensor was converted into digital data by a relaxation oscillator circuit. In addition, a 2.4 GHz wireless communication method was used in this system for wireless data transmission. The proposed flexible capacitive sensor was shown a good performance in the basic experiment of liquid level detection in the plastic IV drip bag, and the wireless detector is able to send the measured data to the receiver in other place by the wireless method. The PC which connected with wireless receiver can give an alarm immediately, when the liquid in the plastic IV drip bag is almost used out. The proposed flexible capacitive sensor is able to attach on the plastic IV drip bag completely, and the experiment data shows that the proposed wireless flexible capacitive sensor detection system is possible to detect the liquid level of the plastic IV drip bag. But in the future, further research is needed.

The Design of Liquid Level Detection System for Oil Tank

The basic principle of liquid level measurement with capacitive sensor is described. According to differences in dielectric constant between oil and water, a liquid level detection system for oil tank is designed. The system includes capacitive sensor, signal processing circuit, FPGA logic circuit and the software of computer. Results show that the system has characteristics of easy operation, high precision. It can detect the change of liquid level accurately and effectively.

Novel Method for ELISA Traces Pipetting System by Air Displacement Pipetting

In the Enzyme-linked immunosorbent assay (ELISA) test, many steps need traces pipetting. The ELISA test results will be different when we use different pipetting ways. Our traces pipetting system is based on the air displacement pipetting principle, comparable to the functioning of hand pipettes. It is applied pressure sensor to realize pressure-based liquid level detection (pLLD) and aspiration monitoring. The monitored system can distinguish the following situations: (1) a correct aspiration; (2) cup empty; (3) tip-blocked; (4) bubbles. Using the air displacement principle into traces pipetting can avoid contamination or dilution by system liquids, and problems with corroded tubing, pumps, etc. It applied pressure sensor to realize pLLD and aspiration monitoring. The results of the real-time monitor module on air displacement pipetting show that the traces pipetting system can agilely distinguish the different liquid pipetting situations. The method of air displacement pipetting offered an effective way for ELISA traces pipetting system.

Agile lensing-based non-contact liquid level optical sensor for extreme environments

To the best of the author's knowledge, demonstrated is the first opto-fluidic technology- based sensor for detection of liquid levels. An opto-fluidic Electronically Controlled Variable Focus Lens (ECVFL) is used to change the spatial intensity profile of the low power optical beam falling on the liquid surface. By observing, tuning and measuring the liquid surface reflected intensity profile to reach its smallest size, the liquid level is determined through a beam spot size versus ECVFL focal length calibration table. Using a 50 μW 632.8 nm laser wavelength liquid illuminating beam, a proof-of-concept sensor is tested using engine oil, vegetable oil, and detergent fluid with measured liquid levels over a 75 cm range. This non-contact Radio Frequency (RF) modulation-free sensor is particularly suited for hazardous fluids in window-accessed sealed containers including liquid carrying vessels in Electromagnetic Interference (EMI) rich environments.

Development of measurement technique for surface waves on high-speed liquid lithium jet for IFMIF target

This paper reports a measurement technique for surface waves on a liquid lithium jet, and its experimental results for the purpose of study on a Li target of the International Fusion Materials Irradiation Facility (IFMIF). The statically characteristic of the waves was successfully clarified by a contact-type liquid level detector and an analysis method of the obtained data newly proposed in this paper. The detail procedure of the measurement method is described in this paper. As the results, it was found that the wave distributions in the all jet velocity range up to 15 m/s were conformed each other in normalized form and Rayleigh distribution which is one of popular model to show irregular water waves, and found that the mean wave height increased with increasing of the flow velocity.

High-sensitivity temperature-independent differential pressure sensor using fiber Bragg gratings

By means of novel packaged-structure design, a temperature independent differential pressure sensor based on fiber Bragg gratings with high sensitivity is experimentally demonstrated. The differential pressure sensitivity of the sensor can reach to 821.87nm/MPa. This device can also be used for simultaneous measurement of temperature and differential pressure, which is suitable for applications involving measurement of liquid level, liquid density or specific gravity detection.

Optical system to detect volume of medical samples in labeled test tubes

A novel system for liquid-level detection is reported. The system uses two different wavelengths of light to detect the liquid level of medical samples in tubes that are covered by an unknown number of paper labels. By measuring the intensity of the transmitted light at two distinct wavelengths and computing their ratio, which is compared to a threshold value, a system was developed that is self-compensating for the number of tube labels and the type of medical sample to be analyzed. A laboratory prototype was built, and the test results were analyzed using different types of medical samples. Based on a series of experiments, the system was found to detect the liquid level of 0.4 mL with a maximum allowable tolerance of ±0.1 mL with better than 99.73% reliability and a total test time of 0.5 s. These results were achieved with test tubes that had up to six layers of labels attached to the outside of the tube, thereby making the tube completely opaque.

Gas-expanded liquids: Determination of the expansion coefficient by an acoustic technique

This paper presents an experimental method for liquid level detection in gas-expanded liquids by the sound speed and amplitude. Volumetric expansion of acetonitrile and 2-propanol as a function of CO 2 pressure was determined between 298–333 K and 0–6 MPa. Propane expansion of 2-propanol was done up to 393 K and up to V/ V 0 = 8. It was clearly demonstrated that this technique is useful also for multiphase detection with high accuracy and for obtaining accurate speed of sound values without calibration. The paper also presents an experimental method for gas composition sensing. The speed of sound and sound attenuation as a function of hydrogen concentration in CO 2 and in propane atmosphere at ambient conditions were measured to obtain information whether an acoustic technique could be an alternative method for the determination of H 2 solubility in liquefied gases and in gas-expanded solvents.

Concepts of phase separation in supercritical processing

Processes using supercritical fluids and especially supercritical fluid extraction (SFE) have been thoroughly investigated as a method to obtain high valuable products for more than 20 years. A lot of scientific effort has been dedicated specially in demonstrating the advantages of SFE with respect to the enhanced nutritional value of the natural extracts obtained. Although thermodynamically consistent, up-scaling of such concepts often fails due to a lack of technically and economically feasible solutions. This work focusses on technical aspects of phase separation and product recovery as a decisive process step in laboratory, pilot and industrial scale extraction of solids and liquids. Different methods of liquid level detection are presented as a way of controlling extract separation automatically. The results are discussed in view of guidelines for finding appropriate solutions to the specific separation problem.

A Method for Liquid Level Detection Under Complicated Boundary Conditions

In this paper a method of liquid level detection by mechanical resonant vibrations is presented which is based on longitudinal vibrations of a steel capillary and is able to detect a liquid surface even if covered with foam, as well as if the fluid container is shut by a cap. The behavior of the vibrating system is calculated by a simple model and compared with experimental results.

A smart optical liquid level sensor based on Hg cladding optical waveguide

A smart optical liquid level sensor based on the theory of connected vessels is introduced. The Hg cladding optical waveguide (HCOW) is taken as its probe, and the change of liquid level is presented by the change of the HCOW length. Both the theoretical analysis and experiments show that when the waveguide diameter and the light wavelength are certain, the optical power loss decreased linearly with the increase of the HCOW length. By detecting the power loss of HCOW, optimizing the structure of probe and selecting the appropriate apparatus for detection, the real time detection of liquid level with high precision can be got. The experimental results show that the measurement accuracy is 5.2 mm within 10 m liquid level, and its theoretical precision can be up to 0.02%.

Liquid-Handling Robotic Workstations for Functional Genomics

More and more functional genomics laboratories are willing to invest in robotic workstations due to the higher throughput liquid-handling intensive nature of the work. In this report, the features of robotic workstations important for functional genomics are discussed. Workstations for functional genomics are useful for replication of clone sets, PCR and sequencing set-up and clean-up, hit picking, gel loading, and nucleic acid purification procedures. Workstations not only increase throughput, but also ensure that assay steps are performed consistently, human error- and learning curve-free from run to run. Workstations fit on a laboratory bench and may have several robotic arms in different configurations. Available configurations include grippers and single-, oligo-, or multi-probe heads, with uniform or independent spanning, and liquid-level detection or tracking options. Most hardware and software packages can be designed for integration with other automated devices, building towards a fully automated system.

A novel liquid level detection method and its implementation

There are various methods and implementations for level detection. Optical methods display a rapid growth among these with their high sensitivities and low costs. In this paper, we propose a new method that uses reciprocally placed LEDs and phototransistors whose optical axes are shifted according to each other. Shifting distance is determined by the direction of the change in the fluid level. The minimum value of the shifting distance depends on dimensions of the LED and the phototransistor. The advantage of this method is that optical properties of the liquid do not have significant effects on level detection phenomenon. Our method can be used in detecting levels of water and inflammable fluids (gasoline, fuel oil, alcohol, etc.).

Design and operation of a fiber optic sensor for liquid level detection

Design and construction of an optical fiber sensor for liquid level detection are reported. This sensor operates based on light intensity modulation, and such modulation results from alteration of total internal reflection into partial reflection at the interface. The modulated intensity has been measured by using a pair of fibers, one transmitting source light, another acting as receiving fiber, and a glass prism providing the total and partial reflections. During the level measurements, when a liquid in a vessel touches the 45° faces of the 45-90-45° prism, the total internal reflection is disturbed, and the reflected light is modulated. The performance of this sensor is tested with different source lights including a light emitting diode (LED), a diode laser, and a He–Ne laser. Extinction ratio has been measured for different liquids, and compared. This ratio for water using LED source is about 0.03, for diode laser is 0.006 and for He–Ne laser is 0.003. Although this device was tested as a liquid level sensor, but the distinct results obtained for samples with different index of refractions demonstrate that the reported sensor can also be used as a liquid refractometer.

Studies on the propagation of light from a light-emitting diode through a glass tube and development of an optosensor for the continuous detection of liquid level

The authors develop a new technique for continuous measurement of liquid level by an optosensor. The objectives are (i) to study the propagation of light from a light-emitting diode (LED) through a glass tube and (ii) based on this principle, to develop a continuous liquid level sensor. The attenuation of light from an LED through a glass tube with distance has been investigated and an empirical relation for it has been established. The result is applied to the detection of water level. The sensor comprises a hollow glass tube with a combined LED- photodetector assembly (the optosensor) and a light reflector inside the tube. The reflector floats on the liquid surface, and light emitted from the LED is detected after reflection from it. The detected light intensity varies with the distance between the optosensor and the reflector. The position of the float changes with the variation of the liquid level. The present level sensor can detect a change of liquid level at distances up to 80 cm with an accuracy of the order of 0.5 mm.