Haiquan Chen

Determination of metal particles in oil using a microfluidic chip-based inductive sensor

ABSTRACT A new microfluidic chip is reported to detect wear particles in oil, and a dual-coil design was studied to improve the sensitivity. Compared to the conventional single-coil inductive sensor, the dual coil is based on the principle of mutual inductance and has a small basic inductance. Therefore, it does not hide the millimeter-size inductive pulses. A series of particles of various sizes were employed to evaluate the performance. Due to the small inductance and the zero distance between wear particles and the coil, the sensitivity of the inductive sensor was greatly improved as iron particles from 5–10 µm in diameter were detected. This simple and economical device is expected to provide useful guidance to improve microfluidic inductive sensors for monitoring and fault detection in industry.

Research on the Output Characteristics of Microfluidic Inductive Sensor

This paper focuses on the output characteristic of the microfluidic inductive sensor. First the coil-metal particle system model is established from Maxwell’s equations. Then series solution is achieved by solving partial differential equation. Finally the numerical simulations and physical experiments are compared on particle feature, particle size, excitation frequency, coil turns, and coil density. The experiments coincide well with the simulations.

Effects of Eddy Current within Particles on the 3D Solenoid Microfluidic Detection Chip

Metal wear debris is an important component of contamination in lubrication oil, and is also an essential information carrier in hydraulic oil. Based on inductive Coulter counting principle, a microfluidic device to detect metal wear debris in oil is presented in this paper. The proposed device can make the distance between the particles in oil and the embedded induction coil very small, and hence greatly improve the sensitivity of the detection. The results indicate that eddy current within particles increase ability to detect copper particles, and decrease the sensitivity to iron particle.

Differentiation of nonferrous metal particles in lubrication oil using an electrical conductivity measurement-based inductive sensor

A method that measures the electrical conductivity of metal based on monitoring the inductance changes of coils via an inductive sensor is introduced in this work to differentiate metal particles in lubrication oil. Theoretical analysis coupled with experimentation is employed to differentiate varieties of nonferrous metal particles, including copper and aluminum particles, ranging from 860 μm to 880 μm in diameter. The results show that the inductive sensor is capable of the identification and differentiation of nonferrous metal particles in lubrication oil based on the electrical conductivity measurement. The concept demonstrated in this paper can be extended to inductive sensors in metal particle detection and other scientific and industrial applications.

Study on Magnetization and Detection the Metal Particle in Harmonic Magnetic Field

Inductance detection methods of metal particle in hydraulic oil are generally based on the inductance change detection. With this method, when particles pass through the microchannel, ferromagnetic and non-ferromagnetic metal particle can be distinguished by monitoring inductance. In this study, it was found that not only inductance pulse but also resistance pulse was produced when detecting particle by inductance detection method. The theory of inductance or resistance change caused by particle is presented from the perspective of electromagnetism in this paper. To verify this phenomenon, the oil sample mixed with different metal particles was forced through the detection coil of microfluidic by constant flow rate. Then several sizes of iron and copper particles were measured. Experimental results showed that the resistance pulses caused by iron particles and copper particles were positive. And for copper particle, SNR (Signal Noise Ratio) of copper particles detected in improved effectively by detecting the resistance pulse.

Research on Rapid Detection and Accounting of Small Particles in Marine Hydraulic Oil

Hydraulic system is widely used in the ship, when the diameter of tiny particles in hydraulic oil exceeds 20μm it indicates that the abnormal wear occurred and the malfunction may cause. This paper uses the light blockage method, the microfluidic detection chip for hydraulic oil detection has been designed and fabricated, a simple and effective optical detection system is developed with the signal amplification and data collection to achieve the detection of tiny particles, and finally through the JAVA programming to count the number of particles in which the diameter is more than 20μm. The results of rapid detections on iron particles with diameter between 25μm and 38μm show the good performance of the detection system and prove that the method is feasible.

Iron Wear Particle Content Measurements in Process Liquids Using Micro Channel – Inductive Method

A detection chip is designed and manufactured to study the relationship between iron wear particle content in hydraulic oil and the detected variation of average inductance, which detects content of iron wear particle by means of micro channel - inductive. Through experiments, we obtained inductive values in the cases. The case is that the sizes of iron wear particle are the same, while the content of iron wear particle are different. Thus the curve between content of iron wear particle content and variation of average inductance was drawn. Experimental results show that the inductance value increases with the increase of the iron wear particle content in hydraulic oil. Experiments prove that the way is feasible for the detection of iron wear particle content in hydraulic oil. This study has an important significance for the realization of iron wear particle content detection in hydraulic oil.

An approach for enhancing dynamic characteristics of differential pressure flow meters

A new differential pressure method for hydraulic flow measurement was proposed. Dynamic response of the flow meter was improved from two choke points. One chock point was canceling the oil induce pipes of traditional ways which limit the dynamic characteristics for liquid volume effect. Pressure differences were generated and measured inside the oil pipe. The other chock point was using a MEMS (Microelectromechanical System) differential sensor in place of normal transducers. Without liquid induce pipes and moving components, this new flow meter measures transient flow perfectly. Working principle of this flow sensor was analyzed theoretically. Using CFD software, the flow field was simulated. Also, in a hydraulic testing system the sensor was calibrated ranging from 0-60L/min. A fast data acquisition system-wavebook 512 was applied during the experiment. It presents good linearity and can meet general hydraulic system use.