CN106066343A - Method and device for particle separation in lubricating oil based on microfluidic chip - Google Patents

Abstract

The invention discloses a device for separating particles in lubricating oil based on a microfluidic chip, which is characterized by comprising the following components: the microfluidic chip comprises a microfluidic chip main body and a substrate which are sequentially arranged from top to bottom; the micro-fluidic chip main body is provided with a main channel for the flow of oil to be detected, and is also provided with an electrode placing channel penetrating through the main channel and a plurality of separation channels symmetrically arranged at two sides of the main channel; the power supply module is communicated with the detection electrode arranged in the electrode arrangement channel, and the electric field intensity of the detection area is changed by adjusting the voltage of the power supply module; the micro-injection pump is communicated with the tail end of the main channel and is used for keeping the vacuum degree of the waste liquid area; and the LED ultraviolet lamp is arranged right above the microfluidic chip. The invention also discloses a separation method of the device, the device of the invention has small occupied area, simple principle and strong practicability, and can realize low cost, simplicity and fast on-line detection.

Description

Method and device for particle separation in lubricating oil based on microfluidic chip

technical field

The invention relates to a technology for separating different types of metals from lubricating oil and metal and non-metallic particles, in particular to a method and device for separating particles in lubricating oil based on a microfluidic chip.

Background technique

Lubricating oil is widely used in mechanical equipment. Lubricating oil contains a large number of pollutants, among which solid pollutants are the most harmful. Metal particles in solid pollutants have high hardness, which can easily cause wear of moving parts of mechanical equipment and cause mechanical failure. In addition, through the study of the material, quantity and size of lubricating oil metal and non-metallic particles, the working status of mechanical equipment can be effectively evaluated, and the failure status of the mechanical equipment can also be predicted.

At present, the requirements for improving the operational safety of mechanical equipment, reducing operating and maintenance costs, and realizing real-time detection of operating status are getting higher and higher. At this time, it is particularly important to carry out online detection of lubricating oil. The key to the detection technology of online lubricating oil lies in the detection sensor. According to the different working principles of sensors, lubricating oil detection can be divided into the following categories: optical methods, acoustic methods, physical and chemical analysis methods, on-line ferrography and other methods and their combinations. These methods have their own characteristics:

The optical method has the advantages of short detection time, real-time measurement, high equipment integration, and wide application in engineering practice; however, the aggregation of metal and non-metal particles, as well as air bubbles and moisture will affect the measurement results, and some impervious Light oils also limit the practical application of this method.

Acoustic methods can distinguish pollutants such as particles and water droplets in lubricating oil. The technical difficulty of this method lies in the installation of sensors and the selection of ultrasonic frequencies. At the same time, the vibration generated by mechanical equipment during operation will reduce the detection accuracy of sensors. The price is also more expensive.

The physical and chemical analysis method refers to the method of detecting and analyzing the physical and chemical indicators of oil samples such as viscosity, flash point, moisture, acid value, and metal abrasive particles in the laboratory. This method has high detection accuracy, and can obtain various performance indicators of the lubricating oil separately, and make a comprehensive analysis, thereby effectively extending the replacement period of the lubricating oil. Commonly used physical and chemical oil analyzers include viscometers, titrators, etc. Due to the long detection time, high cost and complicated operation process of physical and chemical analysis method, it is only used for laboratory measurement and is not suitable for rapid online detection of oil.

Online ferrography technology is an oil detection technology that uses magnetic gradients and gravity gradients to separate metal abrasive particles from lubricating oil and arrange them by size. It can determine the size and type of wear particles in the oil. However, quantitative ferrography has its inaccuracy. Wear particle analysis mainly depends on the knowledge level and practical experience of the operator. Sampling is not representative. It takes a long time to make ferrography, and the analysis speed is not high.

The above-mentioned online lubricating oil detection methods all have certain deficiencies, and cannot fully meet the detection requirements such as low cost, rapidity, and sensitivity.

Contents of the invention

According to the technical problems raised above, a method and device for separating particles in lubricating oil based on a microfluidic chip are provided. The present invention mainly utilizes microfluidic technology, the principle of photoelectric effect and the principle of electric field to separate different types of metals in lubricating oil and the separation of metal and non-metallic particles, so as to provide reference value for the separated oil analysis and quickly carry out online purpose of detection.

The technical means adopted in the present invention are as follows:

A device for separating particles in lubricating oil based on a microfluidic chip, characterized in that it comprises:

A microfluidic chip, the microfluidic chip includes a microfluidic chip body and a substrate sequentially arranged from top to bottom; the microfluidic chip body is provided with a main channel for the flow of the oil to be detected, and the The main body of the microfluidic chip is also provided with an electrode placement channel running through the main channel and a plurality of separation channels symmetrically arranged on both sides of the main channel;

The power supply module is connected to the detection electrode placed in the electrode placement channel, and the electric field intensity in the detection area is changed by adjusting the voltage of the power supply module;

A micro-syringe pump communicated with the tail end of the main channel for maintaining the vacuum in the waste liquid area;

The led ultraviolet lamp is arranged directly above the microfluidic chip.

The above-mentioned power supply module is mainly used to adjust the electric field strength, so as to ensure that the charged metal particles in the oil can be separated by the electric field force; the above-mentioned micro injection pump can be adjusted to suck air from the waste liquid hole at a specific speed, Maintain a vacuum at the waste port. Since the pressure in the waste liquid hole is lower than the pressure in the separation hole of the other separation channels, the oil to be detected can flow smoothly in the main channel, ensuring that the oil will not flow to the separation channel, which is for the separation of charged metal particles Necessary conditions are provided; led ultraviolet lamp ensures that the entire microfluidic channel is within the irradiation range of ultraviolet light. According to the principle of photoelectric effect, when the lubricating oil sample to be tested is irradiated with ultraviolet light of a certain frequency, the metal particles in the oil will be excited by the ultraviolet light and release electrons, thereby being positively charged, and the electricity carried by different metal particles is different. Yes, when the sample oil passes through the detection area, the charged metal particles will be attracted to the separation channel by the electric field force, and the electric field force and initial velocity of different metal particles are different, so different metal particles are Different motion trajectories will be generated, and will flow to different separation channels. Non-metallic particles are not affected by the electric field force in the electric field, and will maintain the original direction of movement and flow to the waste liquid hole. Thereby, the separation between different metal particles and non-metal particles is completed. The frequency of the irradiating light must be chosen to excite the metal particles in the oil, and the light must be maintained throughout the experiment.

Further, the main channel includes a liquid inlet hole at the end of the main channel for injecting lubricating oil samples and a liquid waste hole at the end of the main channel, and the main channel is a rectangular channel.

Further, the detection electrodes are respectively placed on both sides of the main channel, and the two detection electrodes are cylindrical copper rods with the same specification.

Further, the separation channel uses upper and lower rows of separation channels by changing the positive and negative poles of the detection electrodes, and a separation hole is provided at the end of the separation channel. Due to the different speeds and stresses of different metal particles in the electric field, multiple separation channels are provided to make different metal particles flow to different separation channels. The specific number and size of the separation channels can be changed according to the actual situation of the experiment.

The present invention also discloses the separation method based on the microfluidic chip particle separation device in lubricating oil, which is characterized in that it includes the following steps:

S1. Set the micro-injection pump program to pump air into the waste liquid hole at a constant speed, so that the waste liquid hole maintains a low pressure relative to other separation holes of the main body of the microfluidic chip to form a preset vacuum degree;

S2. At the same time, turn on the switch of the led ultraviolet lamp, and drop an appropriate amount of oil sample into the liquid inlet hole with a pipette;

S3. When the oil sample flows through the main channel and enters the detection port where the detection electrode is placed, adjust the electric field strength in the detection area by adjusting the voltage of the power supply module, so that the charged metal particles in the oil sample can be separated from the oil smoothly After coming out, the non-metallic particles are not affected by the electric field force and keep the original direction of movement, and the detection is completed as the oil sample flows to the waste liquid hole.

Compared with the existing technology, this technology has the following advantages:

1. Since the present invention uses a microfluidic chip as a detection platform for separating metal particles and non-metallic particles in oil, the relevant detection equipment is small in size. Compared with large and expensive detection equipment, the present invention has simple structure, easy operation and Features such as portability.

2. The technology and principle adopted in the present invention are simple, and the disadvantages of complicated equipment and low efficiency are overcome. At the same time, the design of the microfluidic channel is simple and convenient, and it has strong practical operability.

3. The present invention uses the photoelectric effect to excite the metal particles in the oil, which is a very simple and fast way to electrify the metal particles.

Based on the above reasons, the present invention can realize low-cost, simple and rapid on-line detection, and can be widely promoted in the fields of lubricating oil detection and the like.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the structure schematic diagram of the separation device of metal and non-metal particles in lubricating oil based on microfluidic chip of the present invention;

Fig. 2 is a structural schematic diagram of the microfluidic detection chip of the present invention;

In the figure: 1. Liquid inlet hole, 2. First separation hole, 3. Second separation hole, 4. Third separation hole, 5. Fourth separation hole, 6. Fifth separation hole, 7. Sixth separation hole , 8, waste liquid hole, 9, first detection electrode, 10, second detection electrode, 11, power supply module, 12, micro injection pump, 13, microfluidic chip main body, 14, led ultraviolet lamp, 15, substrate.

detailed description

In order to make the technical solutions, objectives and advantages adopted by the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings of the embodiments of the present invention. Apparently, the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

A device for separating particles in lubricating oil based on a microfluidic chip, comprising:

A microfluidic chip, the microfluidic chip includes a microfluidic chip body 13 and a substrate 15 arranged sequentially from top to bottom; the microfluidic chip body 13 is provided with a main channel for the flow of oil to be detected The main channel of the microfluidic chip 13 is also provided with an electrode placement channel through the main channel and a plurality of separation channels symmetrically arranged on both sides of the main channel; The inlet hole 1 for lubricating oil sample injection and the waste liquid hole 8 arranged at the end of the main channel, the main channel is a rectangular channel. The detection electrodes are respectively placed on both sides of the main channel, and the two detection electrodes are cylindrical copper rods with the same specifications. The separation channel uses upper and lower rows of separation channels by changing the positive and negative poles of the detection electrodes, and a separation hole is provided at the end of the separation channel.

The power supply module 11 is connected to the detection electrode placed in the electrode placement channel, and the electric field intensity in the detection area is changed by adjusting the voltage of the power supply module 11;

A micro-injection pump 12 communicated with the tail end of the main channel for maintaining the vacuum in the waste liquid area;

The led ultraviolet lamp 14 is arranged directly above the microfluidic chip 13 .

The invention also discloses a separation method based on a particle separation device in lubricating oil of a microfluidic chip, comprising the following steps:

S1. Set the micro-injection pump 12 program, pump air into the waste liquid hole 8 at a constant speed, so that the waste liquid hole 8 maintains a low pressure relative to other separation holes of the microfluidic chip main body 13, and forms a preset vacuum degree;

S2. Turn on the switch of the led ultraviolet lamp 14 at the same time, and drop an appropriate amount of oil sample to the liquid inlet 1 with a pipette;

S3. When the oil sample flows through the main channel and enters the detection port where the detection electrode is placed, the electric field strength in the detection area is adjusted by adjusting the voltage of the power supply module 11, so that the charged metal particles in the oil sample can be smoothly discharged from the oil. After separation, the non-metallic particles are not affected by the electric field force and keep the original direction of movement, and the oil sample flows to the waste liquid hole 8 to complete the detection.

Example 1

As shown in Figure 1, it is a device for separating metal particles from non-metal particles in lubricating oil based on a microfluidic chip. It is mainly composed of a microfluidic chip, copper electrodes, an external power supply module 11, a micro injection pump 12, and an LED ultraviolet lamp 14 with a suitable frequency. As shown in Figure 2, it is a schematic structural view of a microfluidic chip main body 13 and a substrate 15, wherein the microfluidic chip main body 13 is made of PDMS (polydimethylsiloxane) material, and the substrate 15 is made of PMMA (polymethylsiloxane). Methyl acrylate), that is, plexiglass. There is good adhesion between PDMS (polydimethylsiloxane) material and PMMA material, and it has good chemical inertness. There is one main channel on the main body of the microfluidic chip, which is a channel for detecting oil samples; the other is a separation channel symmetrically arranged on both sides of the main channel for separating metal particles in the oil.

As can be seen from Figure 2, from left to right are the oil sample inlet 1, two copper electrodes (the first detection electrode 9 and the second detection electrode 10), 6 separation channels and each separation channel corresponds to one Separation holes (respectively the first separation hole 2, the second separation hole 3, the third separation hole 4, the fourth separation hole 5, the fifth separation hole 6 and the sixth separation hole 7), and the waste water at the end of the main channel Liquid hole 8.

The working principle of the separation device between different metal particles and non-metal particles in the oil based on the microfluidic chip described in the embodiment of the present invention is described in conjunction with Fig. 1 and Fig. 2:

First adjust the program of the micro-injection pump 12 so that it maintains a constant speed to pump air into the waste liquid hole 8, so that the waste liquid hole 8 will maintain a low pressure relative to the other separation holes of the microfluidic chip main body 13, forming a certain vacuum Spend. Turn on the switch of the led ultraviolet lamp 14 simultaneously, and the led ultraviolet lamp 14 is kept on in the whole detection process. Use a pipette to add an appropriate amount of oil sample to the oil sample inlet 1, because at this time the waste liquid hole 8 is a relatively low pressure, and the oil sample dripped into the liquid inlet 1 will slowly flow in the main channel. When the oil sample flows through the detection port, because the pressure in the separation hole is higher than that of the waste liquid hole 8, the oil sample will maintain the original flow direction and will not flow to the separation channel. At the same time, the electric field strength in the detection area is adjusted by adding the power supply module 11, so that the charged metal particles in the oil can be separated from the oil smoothly. The electric field force will also be different, so their movement trajectories when they flow to the separation channel are also different, and the metal particles can be distinguished according to this. The non-metallic particles will not be affected by the electric field force and maintain the original direction of movement, and flow to the waste liquid hole 8 along with the oil.

The embodiment of the present invention provides a method and device for separating metal particles and non-metal particles in lubricating oil based on a microfluidic chip. This method is proposed based on microfluidic technology, the principle of photoelectric effect and the principle of electric field action. The technology and principle used are relatively simple, and the equipment of the detection device is relatively simple, easy to carry, and the cost of detection is low. It is suitable for online test. A new detection method is provided for the distinction between metal particles and non-metal particles and the distinction between metal particles.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (5)

1. A device based on particle separation in microfluidic chip lubricating oil, characterized in that it comprises: A microfluidic chip, the microfluidic chip includes a microfluidic chip body and a substrate sequentially arranged from top to bottom; the microfluidic chip body is provided with a main channel for the flow of the oil to be detected, and the The main body of the microfluidic chip is also provided with an electrode placement channel running through the main channel and a plurality of separation channels symmetrically arranged on both sides of the main channel; The power supply module is connected to the detection electrode placed in the electrode placement channel, and the electric field intensity in the detection area is changed by adjusting the voltage of the power supply module; A micro-syringe pump communicated with the tail end of the main channel for maintaining the vacuum in the waste liquid area; The led ultraviolet lamp is arranged directly above the microfluidic chip. 2. The device for particle separation in lubricating oil based on microfluidic chip according to claim 1, characterized in that: the main channel includes a liquid inlet for lubricating oil sample injection that is arranged at the end of the main channel. hole and a waste liquid hole arranged at the tail end of the main channel, the main channel is a rectangular channel. 3. The device for particle separation based on microfluidic chip lubricating oil according to claim 1, characterized in that: the detection electrodes are respectively placed on both sides of the main channel, and the two detection electrodes are of the same specification. Cylindrical copper rod. 4. The device for particle separation based on the microfluidic chip lubricating oil according to claim 3, characterized in that: the separation channel uses two rows of separation channels up and down by changing the positive and negative electrodes of the detection electrode, and the A separation hole is provided at the end of the separation channel. 5. A separation method based on a particle separation device in microfluidic chip lubricating oil, characterized in that it comprises the steps: S1. Set the micro-injection pump program to pump air into the waste liquid hole at a constant speed, so that the waste liquid hole maintains a low pressure relative to other separation holes of the main body of the microfluidic chip to form a preset vacuum degree; S2. At the same time, turn on the switch of the led ultraviolet lamp, and drop an appropriate amount of oil sample into the liquid inlet hole with a pipette; S3. When the oil sample flows through the main channel and enters the detection port where the detection electrode is placed, adjust the electric field strength in the detection area by adjusting the voltage of the power supply module, so that the charged metal particles in the oil sample can be separated from the oil smoothly After coming out, the non-metallic particles are not affected by the electric field force and keep the original direction of movement, and the detection is completed as the oil sample flows to the waste liquid hole.