Abstract:
A multi-channel magnetic control system is provided, which is used for mixing fluids containing magnetic particles or separating magnetic species. In the multi-channel magnetic control system, a plurality of magnetic field switches are allocated to surround a plurality of channels, and the magnetization directions of the magnetic field switches are controlled to generate an uneven local magnetic field gradient, so as to achieve the purpose of fluid mixing or separating the magnetic species. This system can be also used as controllable flow resistance devices for magnetic fluids. Based on the demand of magnetic field distribution, overall or local control of the magnetic field switches can be executed to perform parallel processing over the multi-channel system of multi-dimensional allocation, so as to effectively save the processing time. The mixing or separation rate can be obtained via detecting residual magnetic species by magnetoresistive sensors arranged in inlets and outlets of channels.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Taiwan Patent Application No. 104131189, filed on Sep. 21, 2015, in the Taiwan Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present disclosure generally relates to a multi-channel magnetic control system which applies a plurality of magnetic elements consisted of magnetic elements having different magnetic anisotropies to control the magnetic cluster of the channel system, and the disclosed multi-channel magnetic control system is capable of magnetizing the magnetic species in the channel to interfere the magnetic field, so as to mix the magnetic fluids or to separate the magnetic species from the fluids. 
         [0004]    2. Description of the Related Art 
         [0005]    With the rapid development of the biochip and the biomedical microsystem, mixing fluids and separating species in the channel have become a hot spot in the research. As far as the continuously flowing fluids are concerned, the fluid mix and species separation can be divided into active and passive types. The active type, which is to apply electricity or magnetization to the fluids or species, is more flexible and therefore popularized. In addition, as the magnetic fluids and particles have been applying to the biochip nowadays, research to achieve more effectiveness on the use of magnetic species to mix or collect magnetically targeted species have been focused. 
         [0006]    The conventional technique is to use an electromagnet as a magnetic field switch to mix fluids or to separate species. Although it is easy to adjust the magnetic field intensity, the electromagnet also generates heat along with the magnetic field, such that the temperature is changed and the characteristic of the fluids or species is also affected due to the temperature variation. Moreover, using the electromagnet as the magnetic field switch needs to continuously supply current. In addition, it is hard to manufacture the micro-coil by the existing micro-nano manufacturing technology. Therefore, alternatives of the magnetic field switch have to be taken into account. 
         [0007]    As a result, the inventor of the present disclosure has been mulling the technical problems over and then designs a multi-channel magnetic control system aims at improving the current shortcomings so as to promote the industrial practicality. 
       SUMMARY OF THE INVENTION 
       [0008]    In view of the aforementioned technical problems, one objective of the present disclosure provides a multi-channel magnetic control system which switches the magnetic field switch by controlling the magnetization direction of the magnetic element. When the magnetic element is turned on, the magnetic fluids or species in the channel are magnetized to change the fluid direction, such that the purpose of mixing fluids or separating species is achieved. Besides, the magnetic element can be turned off when it is not in use. 
         [0009]    In view of the aforementioned technical problems, another objective of the present disclosure provides a multi-channel magnetic control system, wherein the magnetic field switch of the multi-channel magnetic control system is consisted of magnetic element. After being magnetized, the magnetic element maintains the pure magnetic moment without the continuous apply of an external electric field, and therefore the continuous supply of current becomes unnecessary. Consequently, the magnetic field can be generated without continuously supplying current so that the thermal effect is therefore avoided and electricity consumption becomes dispensable. 
         [0010]    In view of the aforementioned technical problems, yet another objective of the present disclosure applies the channel to arrange in a multi-dimensional arrangement and arranges a plurality of magnetic field switches to simultaneously mix fluids and/or separate magnetic species, so as to effectively save the processing time. 
         [0011]    In accordance with the aforementioned objectives, the present disclosure provides a multi-channel magnetic control system including: a plurality of channels arranged in a two-dimensional model or a three-dimensional model; a plurality of magnetic field switches disposed between the plurality of channels, wherein at least one magnetic field switch may be shared by at least two channels, and each magnetic field switch may include a plurality of magnetic elements having respective switching magnetic fields; and a control module changing a magnetization direction of the magnetic elements of the at least one magnetic field switch according to a magnetic field distribution demand, so as to generate a local magnetic field gradient in the plurality of channels. 
         [0012]    Preferably, the plurality of magnetic field switches allocated at two sides of at least one channel may be arranged in a corresponding arrangement, a staggering arrangement or a combination thereof. 
         [0013]    Preferably, the plurality of magnetic field switches allocated at the same side of at least one channel may be arranged in a fixed distance respectively. 
         [0014]    Preferably, the fixed distance may be between 0.1 μm and 2000 μm. 
         [0015]    Preferably, the plurality of magnetic switches disposed between two channels which are adjacent to each other may be shared by the two channels. 
         [0016]    Preferably, the control module may control a magnetization direction of the magnetic field switches intermittently to increase a mixing efficiency of mixing and/or separating fluids in the plurality of channels. 
         [0017]    Preferably, the control module may control the magnetization direction of the magnetic field switches according to a demand of flow resistance. 
         [0018]    Preferably, an inlet and an outlet of the channels may further be disposed with a magnetoresistive sensor respectively to sense a degree of mixing of a fluid or a residual rate of a magnetic species that is separated. 
         [0019]    Preferably, the control module may control the plurality of magnetic field switches entirely or locally according to the magnetic field distribution demand. 
         [0020]    Preferably, each switching magnetic field may be generated from same or different magnetic materials having different magnetic anisotropies. 
         [0021]    Preferably, the magnetic element may be a stacked multilayer film, a plurality of separated films or a plurality of separated multilayer films. 
         [0022]    Preferably, the plurality of magnetic elements may correspond to respective switching magnetic fields, and each switching magnetic field may be generated from same or different magnetic materials having different magnetic anisotropies. 
         [0023]    Preferably, each magnetic anisotropy of the magnetic elements is generated from a shape anisotropy or a lattice anisotropy. 
         [0024]    The multi-channel magnetic control system of the present disclosure may have one or more advantages as follows. 
         [0025]    1. Decrease of power consumption. Utilizing the characteristics of ferromagnetic materials, after obtaining the magnetic property from an external magnetic field, the magnetic material is still capable of maintaining the magnetic property even if the external magnetic field disappears. As a result, the magnetic field can be generated without continuously supplying current, so that the power consumption is decreased. 
         [0026]    2. Prevention of the thermal effect. As continuously supplying electrical field is unnecessary for maintaining the magnetic field, the heat is therefore greatly decreased. Consequently, the multi-channel magnetic control system of the present disclosure can avoid the temperature variation and the thermal effect. 
         [0027]    3. Simultaneous process. By means of the multi-dimensional arrangement and the arrangement of a plurality of magnetic field switches, mixing of fluids containing magnetic particles and/or separating magnetic species can be performed simultaneously to save the processing time. 
         [0028]    4. Increase of efficiency. According to the magnetic field distribution demand, the magnetization direction of the magnetic field switches can be controlled entirely or locally to promote the mixing efficiency and/or separation efficiency of the fluids in the channel. 
         [0029]    With these and other objects, advantages, and features of the invention that may become hereinafter apparent, the nature of the invention may be more clearly understood by reference to the detailed description of the invention, the embodiments and to the several drawings herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    For better understanding, like elements are designated by like reference numerals in the accompanying drawings and the following description for the embodiments. 
           [0031]      FIG. 1  is a schematic diagram illustrating the structure of the multi-channel magnetic control system of the present disclosure. 
           [0032]      FIG. 2  is a schematic diagram illustrating the conception of the magnetic field switch of the multi-channel magnetic control system of the present disclosure. 
           [0033]      FIG. 3  is a schematic diagram illustrating the fluid mix of the multi-channel magnetic control system of the present disclosure. 
           [0034]      FIG. 4  is a diagram showing the experiment result of fluid mix of the multi-channel magnetic control system of the present disclosure. 
           [0035]      FIG. 5  is a schematic diagram illustrating the species separation of the multi-channel magnetic control system of the present disclosure. 
           [0036]      FIG. 6  is a schematic diagram illustrating the configuration of two adjacent channels, which are both performing fluid mix, of the multi-channel magnetic control system of the present disclosure. 
           [0037]      FIG. 7  is a schematic diagram illustrating the configuration of two adjacent channels, which are both performing fluid mix and species separation simultaneously, of the multi-channel magnetic control system of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0038]    In order to facilitate the understanding of the technical features, the contents and the advantages of the present disclosure, and the effectiveness thereof that can be achieved, the present disclosure will be illustrated in detail below through embodiments with reference to the accompanying drawings. On the other hand, the diagrams used herein are merely intended to be schematic and auxiliary to the specification, but are not necessary to be true scale and precise configuration after implementing the present disclosure. Thus, it should not be interpreted in accordance with the scale and the configuration of the accompanying drawings to limit the scope of the present disclosure on the practical implementation. 
         [0039]    Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present disclosure pertains can realize the present disclosure. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. 
         [0040]    Please refer to  FIG. 1  which is a schematic diagram illustrating the structure of the multi-channel magnetic control system of the present disclosure. As shown in the figure, a multi-channel magnetic control system of the present disclosure includes a plurality of channels  10 , a plurality of magnetic field switches  20  and a control module  30 . The plurality of channels  10  can be arranged in a two-dimensional model or a three-dimensional model according to the actual requirement or application. In practice, it can further extend in the space with an arbitrary direction. 
         [0041]    The plurality of magnetic field switches  20  are respectively disposed between the plurality of channels  10 , wherein at least one magnetic field switch  20  is shared by at least two channels  10 . Each magnetic field switch  20  includes a plurality of magnetic elements characterized of respective magnetic anisotropies. The plurality of magnetic field switches  20  allocated at two sides of at least one channel  10  are arranged in a corresponding arrangement, a staggering arrangement, or a combination thereof. 
         [0042]    For example, each magnetic field switch  20  includes two magnetic elements  21  having a smaller magnetic anisotropy and one magnetic element  22  having a larger magnetic anisotropy. The magnetic element is made of a magnetic material, and can be formed by a stacked multilayer film, a plurality of separated films, or a plurality of separated multilayer films. But it shall be not limited thereto. 
         [0043]    The control module  30  changes a magnetization direction of the magnetic elements of at least one the magnetic field switch  20  according to a magnetic field distribution demand, so as to generate a local magnetic field gradient in the plurality of channels  10 . The control module  30  controls the magnetization direction of the magnetic field switch  20  intermittently so as to increase the efficiency of mixing fluid containing magnetic particles and/or separating magnetic species in the plurality of channels  10 . 
         [0044]    Please refer to  FIG. 2  which is a schematic diagram illustrating the conception of the magnetic field switch of the multi-channel magnetic control system of the present disclosure. As shown in the figure, the two magnetic elements  21  having the smaller magnetic anisotropy and the magnetic element  22  having the larger magnetic anisotropy are made of magnetic materials characterized of respective switching magnetic fields. The switching magnetic fields are generated from the same magnetic material characterized of different magnetic properties or anisotropies such as shape anisotropy, lattice anisotropy, or from various magnetic materials, indicating that the two magnetic elements  21  having the smaller magnetic anisotropy and the magnetic element  22  having the larger magnetic anisotropy have respective switching magnetic fields for switching the magnetization direction. 
         [0045]    When arranging the magnetic elements having different magnetic anisotropies, an external magnetic field with larger magnitude is added to magnetize all the magnetic elements to the same magnetization direction (the arrowheads of the magnetic elements), that is, the north and south magnetic poles of all the magnetic elements are magnetized to the same direction, such that these magnetic elements are combined to become a large magnet so as to form a strong magnetic cluster  82 , and then the magnetic field switch  20  is defined as “ON”. 
         [0046]    Similarly, when an external magnetic field which has a magnetization direction opposing to an initial magnetization direction of a magnetic element is added and the external magnetic field can only enable the two magnetic elements  21  having the smaller magnetic anisotropy to generate the magnetization switching, therefore the magnetic poles of the two magnetic elements  21  having the smaller magnetic anisotropy will have a reverse direction to the magnetic pole of the magnetic element  22  having the larger magnetic anisotropy. As a result, the magnetic field of the two magnetic elements  21  having the smaller magnetic anisotropy inters the end point of the magnetic element  22  having the larger magnetic anisotropy to form a weak magnetic cluster  84 . The aspect is applied to define the magnetic field switch  20  to be “OFF”. 
         [0047]    Please refer to  FIG. 3  and  FIG. 4  together. As shown in the figures, in the multi-channel magnetic control system of the present disclosure, the magnetic field switches  20  allocated at one side of at least one channel  10  is arranged in a fixed distance d, and the magnetic field switches  20  allocated at opposing sides of the at least one channel  10  is allocated with a staggering arrangement. The fixed distance d is between 0.1 μm and 2000 μm. In practice, when the magnetic element of the magnetic field switch  20  is a stacked multilayer film, the gap between each fixed distance is smaller than 0.1 μm. 
         [0048]    Firstly, a magnetic fluid  41  and a non-magnetic fluid  42  are introduced into the channel  10 . If the magnetic field switches  20  allocated at two sides of the channel  10  are not turned on, the magnetic fluid  41  and the non-magnetic fluid  42  will only be slightly mixed after flowing a long distance. 
         [0049]    When mixing the fluids, the plurality of magnetic field switches  20  are turned on, and the strong magnetic cluster  82  of the plurality of magnetic field switches  20  affects the magnetic fluid  41  magnetically to draw the magnetic fluid  41  towards the plurality of magnetic field switches  20  while ruling out the non-magnetic fluid  42 , enabling the flow path of the fluids to have a curve trend so as to increase the contact length and the contact time between the fluids and to cause a chaotic flow field to mix the fluids. As a result, it can enhance the mixing efficiency of the magnetic fluid  41  and the non-magnetic fluid  42 , such that when the magnetic fluid  41  and the non-magnetic fluid  42  flow through the plurality of magnetic field switches  20 , they are mixed to become an even fluid  43 . 
         [0050]      FIG. 4  also illustrates that the mixing efficiency varies with the variation of the magnetic cluster intensity of the plurality of magnetic field switches  20 . The plurality of magnetic field switches  20  are allocated in a distance starting from an inlet of the channel  10  to 500 μm. When a conducted magnetic field intensity is over 30000 A/m, the mixing efficiency is over 84% in 1500 μm of the channel  10 . The experiment result also shows that the stronger the magnetic field intensity is, the better the mixing efficiency will become. Therefore, the experiment results verify that the multi-channel magnetic control system of the present disclosure does promote the mixing efficiency of the even fluid  43 . 
         [0051]    Please refer to  FIG. 5  which is a schematic diagram illustrating the magnetic species  50  separation of the multi-channel magnetic control system of the present disclosure. The plurality of magnetic field switches  20  are allocated at two sides of the channel  10  correspondingly. Besides, the magnetic field switches  20  allocated at the same side is still arranged in the fixed distance d. 
         [0052]    As shown in the figure, the fluid containing the magnetic species  50  is introduced into the channel  10 . If the plurality of magnetic field switches  20  allocated at two sides of the channel  10  are not turned on, the fluid is not affected. When the plurality of magnetic field switches  20  allocated at two sides of the channel  10  are turned on, the strong magnetic cluster  82  of the plurality of magnetic field switches  20  draws the magnetic species  50  from the channel  10  towards the plurality of magnetic field switches  20 . The amount of drawn magnetic species  51  which adhere to the periphery of the wall of the channel  10  is obviously greater than the amount of other magnetic species  52  which keep flowing through the channel  10 . This proves that the plurality of magnetic field switches  20  can effectively draw and capture most magnetic species  50 . 
         [0053]    When the plurality of magnetic field switches  20  are “OFF”, the weak magnetic cluster  84  releases the magnetic species  51  back to the channel  10  and the magnetic species  50  can be collected in the outlet of the channel  10 , such that the purpose of separating the magnetic species  50  is achieved. 
         [0054]    Please refer to  FIG. 6 . As shown in the figure, the present embodiment shows an example when two channels  10  are parallel to each other, and the plurality of magnetic field switches  20  between the two adjacent channels  10  are being shared by the two channels  10 . The control module  30  is applied to adjust the plurality of magnetic field switches  20  entirely or locally according to the magnetic field distribution demand. 
         [0055]    When the two adjacent channels  10  are performing fluid mix simultaneously, the plurality of magnetic field switches  20  are allocated with a staggering arrangement outside the periphery of the channels  10 . As the magnetic cluster of the plurality of magnetic field switches  20  is surrounding in a cubical space, it can magnetically affect the two channels  10  simultaneously. When the plurality of magnetic field switches  20  are “ON”, the mixing efficiencies of both the magnetic fluid  41  and the non-magnetic fluid  42  are increased in the two channels  10 . Compared with single channel  10 , the two channels  10  are capable of processing a double fluid volume. In addition, as the plurality of magnetic field switches  20  can be shared, the cost is therefore decreased. 
         [0056]    Please refer to  FIG. 7 . The arrangement of the magnetic field switches  20  is similar to  FIG. 6 . The difference between  FIG. 7  and  FIG. 6  lies that the plurality of magnetic field switches  20  allocated on an upper channel  10  and at a lower channel  10  have different allocations. 
         [0057]    If the fluid mix and species separation are performed in the channel system, the plurality of magnetic field switches  20  allocated on the upper channel  10  have the staggering arrangement, and the upper channel  10  is served for mixing the flow. The plurality of magnetic field switches  20  allocated at the lower channel  10  are a corresponding arrangement and the lower channel  10  is applied to separate the magnetic species  50 . 
         [0058]    The plurality of magnetic field switches  20  allocated at two sides of the channel  10  can have various arrangements, so that it is capable of producing different effects of mixing fluid and separating species. In addition, the control module  30  adjusts the plurality of magnetic field switches  20  entirely or locally according to the magnetic field distribution demand to generate different local magnetic field gradients having different intensities. To be more precise, when the local magnetic field gradient is generated, separating the magnetic species  50  according to the magnetic moment of the magnetic species  50  can be achieved so as to sieve the magnetic species  50 . 
         [0059]    The magnetic field switch of the present disclosure is consisted of a plurality of magnetic elements having respective magnetic anisotropies. The magnetic anisotropy characteristics of the magnetic element enable the magnetic element to be magnetized in a short period of time by the external magnetic field, and the magnetization and the pole strength of the magnetic element can be maintained for a long while without continuously supplying energy. The magnetic field switch of the present disclosure is therefore capable of decreasing the power consumption and the temperature variation compared to the conventional electromagnet which is continuously energized. 
         [0060]    By means of the magnetic control system, the present disclosure is capable of entirely or locally control the parameters such as the operation frequency and the magnetic field intensity according to the actual magnetic field distribution demand, so as to generate local magnetic field gradients having different intensities. In addition, based on the flow resistance demand, the system can be also used as controllable flow resistance device for magnetic fluids. 
         [0061]    By means of the multi-dimensional arrangement and the arrangement of a plurality of magnetic field switches, the present disclosure is capable of simultaneously mixing and/or separating fluid to effectively save the processing time. Besides, the inlet and outlet of the channel of the present disclosure are further disposed with a magnetoresistive sensor respectively to sense a degree of mixing of a fluid or a residual rate of a magnetic species that is separated. 
         [0062]    While the means of specific embodiments in present disclosure has been described by reference drawings, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims. The modifications and variations should in a range limited by the specification of the present disclosure.