JP4588376B2 - Magnetic particle adsorption amount detection device - Google Patents

Description

  The present invention relates to a magnetic particle adsorption amount detection device, and more specifically, to adsorb magnetic foreign matter in a permanent magnet type iron removal device that uses a permanent magnet to remove / select magnetic particles from a raw material as foreign matters. The present invention relates to improvement of a magnetic particle adsorption amount detection device for detecting and notifying a state.

  Conventionally, permanent magnet type iron removal devices have been used for magnetic particles (magnetic metal particles or small pieces having magnetic components such as iron) mixed in raw materials such as food materials and chemical products (synthetic resin) materials. It is used to sort out and remove objects or particles containing the magnetic metal or small pieces of magnetic or weak magnetic objects as foreign substances using a permanent magnet, and is also called a permanent magnet type foreign substance sorter. ing.

In such a permanent magnet type iron removing device, when the amount of magnetic foreign matter attracted by the permanent magnet increases, the magnetic force acting on newly arrived foreign matter decreases and the foreign matter removal / sorting function is lowered. It is necessary to know when to clean the magnetic foreign matter. For this purpose, as shown in Patent Document 1, a pilot permanent magnet body is used to create the same simulated state as the environment in which foreign matter is attracted to the permanent magnet body for foreign matter removal / sorting in the permanent magnet type iron removing device, It has been proposed to mechanically easily detect the foreign matter adsorption state by physically observing the amount of foreign matter adsorption to the pilot permanent magnet body.
JP 2000-237627 A

  In Patent Document 1, as a specific mechanism for observing the amount of adsorbed foreign matter, a torque that connects a load cell type (Patent Document 1: FIGS. 2 and 4) that connects a load cell to a pilot permanent magnet body and a torque sensor. A sensor type (Patent Document 1: Paragraphs [0030], [0031], [0048] to [0050]) has been proposed.

However, the load cell type has the following problems (1) to (4):
(1) The balance between the load cell and the counterweight is just like a balance, so it is easily affected by vibration.
(2) Since the change in force due to the magnetic foreign matter adsorbed on the outer tube surface of the pilot permanent magnet body is limited to the vertical increase / decrease, the increase / decrease of the magnetic foreign matter adsorbed directly beside the outer tube cannot be measured. In addition, since the force due to the magnetic foreign matter adsorbed on the top and bottom of the outer tube cancels out, the amount of adsorption can be measured only by subtracting the amount of foreign foreign matter adsorbed on the upper side of the outer tube. When the increase in the foreign matter adsorption amount reaches a detectable level, a situation may occur in which the foreign matter adsorption amount has already exceeded the foreign matter adsorption limit value to be determined.
(3) Since the detection device including the pilot permanent magnet body and the load cell must always be set horizontally, the installation location of the production line and its use are limited.
(4) The cost increases due to the precision of the load cell and counterweight.

  In the case of the torque sensor type, even if an axial rotational force is applied to the pilot permanent magnet body by a torque motor, it is generated between the magnetic foreign matter adsorbed on the outer surface of the pilot permanent magnet body and the pilot permanent magnet body. Therefore, there is a problem that a high-accuracy torque sensor capable of detecting a very low torque value must be used.

  In view of such a problem, the present invention relates to an aspect of adsorption of magnetic particles to a permanent magnet in a permanent magnet type iron removal device or the like that uses a permanent magnet to remove / select magnetic particles as foreign matter. A magnetic particle adsorption amount detection device that can accurately and independently simulate such a magnetic particle adsorption state with a simple structure and mechanism. The purpose is to provide.

  According to the main feature of the present invention, a cylindrical permanent magnet body (1) is rotatably accommodated inside a cylindrical outer tube (2), and the outer tube (2) is generated by the magnetic force of the permanent magnet body (1). Magnetic particle adsorbing means (A) for adsorbing magnetic particles (MP) on the outer surface of the motor, a motor (4) for rotating the permanent magnet body (1) by power supply, and magnetism adsorbed on the outer tube (2) The torque generated by the motor (4) is electrically measured against the rotational resistance caused by the magnetic force between the particles (MP) and the permanent magnet body (1), and the torque is measured based on the measured torque. An adsorption amount detecting means (72) for determining the amount of the magnetic particles (MP), and the permanent magnet body (1) includes a cylindrical permanent magnet piece (M1 to Mn) and a plate-like magnetic electrode plate ( Pt1 to Ptn + 1) are alternately connected, and each magnetic plate (Pt1 to Pt) n + 1), the magnetic particle-adsorbing amount detection device having a peripheral shape (Ct) to vary the magnetic flux distribution generated in the outer surface of the (? v) in the circumferential direction of the outer tube (2) [Claim 1] is provided. The parentheses are reference symbols or terms used in the embodiments for the sake of understanding.

  The adsorption amount detection means (72) of the magnetic particle adsorption amount detection device according to the present invention detects and detects the drive current of the motor (4) as an electrical measurement amount corresponding to the torque generated by the motor (4). The amount of the magnetic particles (MP) adsorbed on the outer tube (2) is preferably determined on the basis of the driving current (claim 2).

  The magnetic particle adsorption amount detection device according to the present invention uses the magnetic particle adsorption means (A) as a pilot permanent magnet body installed in the raw material supply path, as in the device of Patent Document 1, and uses a permanent magnet type iron removal device or the like. The same simulated state as that in which the foreign matter is attracted to the foreign matter removing / sorting permanent magnet body is created, and the amount of foreign matter adsorbed on the magnetic particle attracting means (A) is electrically observed.

In the present invention, in particular, as a structural feature of the magnetic particle adsorbing means (A), a cylindrical (rod-shaped) permanent magnet body serving as a magnetic source for adsorbing the magnetic particles (MP) to the outer surface of the outer tube (2). The periphery of the electrode plates (Pt1 to Ptn + 1), which are the constituent elements of (1), is shaped so that the magnetic flux distribution generated on the outer surface of the outer tube (2) changes in the circumferential direction. Further, as a drive mechanism feature for the rod-shaped permanent magnet body (1), the rod-shaped permanent magnet body (1) is loosely fitted inside the outer tube (2) so as to be rotatable, and a motor (4 which is always supplied with power) (4). ). Then, by the adsorption amount detection means (72), the motor (with the rotational resistance generated by the magnetic force between the magnetic particles (MP) adsorbed on the outer tube (2) and the permanent magnet body (1) is countered. The torque generated by 4) is electrically measured, and the amount of the magnetic particles (MP) is determined based on the measured torque. In this case, the drive current of the motor (4) is detected as an electrical measurement amount corresponding to the torque, and the amount of the magnetic particles (MP) adsorbed on the outer tube (2) based on the detected drive current. Is preferably determined.

  That is, in the present invention, the peripheral shape of the pole plate (Pt1 to Ptn + 1) is made non-circular, and the circumferential magnetic flux distribution (Φv) on the outer surface of the outer tube (2) by the rod-like permanent magnet body (1) is made strong and weak. When the rod-shaped permanent magnet body (1) is rotated by the motor (4), the magnetic force generated between the magnetic particles (MP) adsorbed on the outer tube (2) and the rod-shaped permanent magnet body (1) The principle of generating rotational resistance acting in the circumferential direction is used.

  In the magnetic particle adsorbing amount detecting device according to the present invention, according to this principle, the structure of the rod-shaped permanent magnet body (1) has a peripheral shape of the plate-like electrode plates (Pt1 to Ptn + 1) by notching (Ct) or the like. Is non-circular. In addition, the both ends (1b, 1c) of the rotating shaft (1a) of the rod-shaped permanent magnet body (1) are supported by bearings (3a, 3b), etc. in the magnetic outer tube (2) such as stainless steel. The rod-shaped permanent magnet body (1) is set so as to be rotatable, and the drive shaft (4a) of the motor (4) is connected to one end (1c) of the rotating shaft (1a), thereby the rod-shaped permanent magnet body (1 ) Is rotated by the motor (4), and the drive mechanism is also used to rotate the magnetic flux distribution (Φv) that is strengthened in the circumferential direction on the outer surface of the outer tube (2) according to the peripheral shape of the electrode plates (Pt1 to Ptn + 1) Is done.

  With such a structure and mechanism, the magnetic force generated between the rod-shaped permanent magnet body (1) and the magnetic particle body (MP) as the magnetic particle body (MP) adsorbed to the outer tube (2) increases. The rotation resistance accompanying the increase also increases, and the motor (4) attempts to increase the generated torque against this rotation resistance. Therefore, the adsorption amount detection means (72) electrically detects this torque increase (for example, By observing an increase in motor current), it is possible to know an increase in the amount of magnetic particle adsorption.

  Therefore, according to the present invention, not only can the magnetic particle adsorption mode to the permanent magnet in the permanent magnet type iron removing device etc. be accurately simulated independently of the iron removing device etc., but also the magnetic particle adsorption Quantifying the magnetic particle adsorption state using a simple structure that simply devises the peripheral shape of the electrode plate in the means (pilot permanent magnet body) and a simple drive mechanism that simply rotates this magnetic particle adsorption means Can be reliably detected.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are merely examples, and various modifications can be made without departing from the spirit of the present invention.

  FIG. 1 shows a magnetic particle adsorption amount detection device according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the difference in magnetic flux distribution based on the pole plate shape of the magnetic particle adsorption amount detection device. . Here, the essential points of this magnetic particle adsorption amount detection device will be described very simply with reference to FIG.

  In the magnetic particle adsorption amount detection device according to one embodiment of the present invention, the pilot magnet structure part A used as pilot magnetic particle adsorption means of a permanent magnet type iron removing device (not shown) has a permanent magnet piece M1. ~ Mn and plate-like electrode plates Pt1 to Ptn + 1 are alternately connected to each other, and a rod-like permanent magnet body 1 is rotatably housed inside the outer tube 2. The magnetic particles MP can be adsorbed on the surface. The peripheral shape of each of the pole plates Pt1 to Ptn + 1 of the rod-shaped permanent magnet body 1 is made noncircular by a notch (Ct) or the like, and thereby, the non-uniform magnetic flux distribution that changes in the circumferential direction ( Φv) is generated. Since the rod-shaped permanent magnet body 1 is always rotated by the motor (4) to rotate the non-uniform magnetic flux distribution (Φv) in the circumferential direction, a rotational resistance is generated between the rod-shaped permanent magnet body 1 and the magnetic particle MP. The torque measurement circuit 72 measures an electrical physical quantity (current) corresponding to the torque generated by the motor 4 against this rotational resistance, and determines the adsorption amount of the magnetic particles MP based on the measured electrical physical quantity. .

  Hereinafter, it will be described in more detail with reference to FIG. 1 and FIG. As shown in FIG. 1, a magnetic particle adsorption amount detection device according to an embodiment of the present invention includes a rod-shaped permanent magnet body 1, also called “(permanent) rod magnet”, a cylindrical stainless steel outer tube 2, a rod-shaped permanent magnet. Bearings 3 a and 3 b for rotatably supporting the magnet body 1 in the outer tube 2, a small motor 4 for rotating the rod-like permanent magnet body 1, a motor case 5 for supporting the motor 4, and supplying power to the motor 4 Power supply terminal board 6, a control device 7 and the like. Here, the rod-shaped permanent magnet body 1, the outer tube 2, and the bearings 3a and 3b constitute a pilot magnet assembly part A of the magnetic particle adsorption amount detection mechanism, and the motor 4 and the motor case 5 constitute the magnetic particle adsorption amount detection mechanism. The drive part B is comprised. The control device 7 is connected to the motor 4 via the terminal board 6 and the motor power supply line.

  The rod-like permanent magnet body 1 has a large number of columnar or disk-like magnet pieces M1 to Mn in the same manner as the permanent magnet structure (not shown; see FIG. 1 of Patent Document 1) of the permanent magnet type iron removal device to be simulated. And a magnetic source for adsorbing magnetic particles whose main elements are the plate-like and highly magnetic iron electrode plates Pt1 to Ptn + 1. As shown in the figure, the magnet pieces M1, M2, M3,..., Mn are adjacent to each other with the polarity of the end face magnetic poles reversed (that is, the opposite end faces of the adjacent magnet pieces have the same polarity), and each pole plate Pt1. , Pt2, Pt3,..., Ptn, Ptn + 1.

  These magnet pieces M1 to Mn include, for example, Fe-Nd-B-based neodymium / iron / boron magnets (also simply referred to as “neodymium magnets”) and Sm—Co-based samarium / cobalt magnets (also simply referred to as “samarium magnets”). An ultra-high magnetic permanent magnet such as The electrode plates Pt1 to Ptn + 1 are made of a ferromagnetic magnetic material (iron), and have a function of attracting magnetic particles (foreign matter) in the raw material to the surface of the outer tube 2. The shape of each of the electrode plates Pt1 to Ptn + 1 is not a perfect disk, but is provided with a notch Ct, for example, as shown in FIG. A non-uniform magnetic flux distribution Φv with high and low density can be formed.

  The magnet pieces M1 to Mn and the electrode plates Pt1 to Ptn + 1 are tightened from the outside of the electrode plates Pt1 and Ptn + 1 by screws (not shown) that engage with the screw grooves of the rotating shaft 1a penetrating the shaft center portion. And integrated with the rotary shaft 1a. Further, shaft end members 1b and 1c are coupled to both ends of the rotating shaft 1a adjacent to the electrode plates Pt1 and Ptn + 1.

  The outer diameter of the rod-shaped permanent magnet body 1 is slightly smaller than the inner diameter of the outer tube 2, which is also referred to as an “outer cylinder”, and is rotatably accommodated (freely fitted) inside the outer tube 2. The outer tube 2 is closed at one end (the left side in the figure) and is called a “bottom”, and the other end (the right side in the figure) is open. Bearings 3a and 3b for supporting the shaft end members 1b and 1c of the rod-like permanent magnet body 1 are attached to the inner peripheral surfaces of the bottom (left side in the figure) and the opening (right side in the figure) of the outer tube 2, Both bearings 3a and 3b support the rod-shaped permanent magnet body 1 in the outer tube 2 so as to be rotatable. The pilot magnet structure A composed of these elements 1, 2, 3a and 3b is provided at an appropriate position in the raw material supply path that can simulate the adsorption operation of the magnetic particles by the permanent magnet structure of the permanent magnet type iron removing device. Be placed.

  Further, the flange member at the opening of the outer tube 2 and the flange member at the opening (left side in the figure) of the motor case 5 are combined, and the shaft end member 1c of the rod-shaped permanent magnet body 1 is aligned with the axis. The drive shaft 4a of the small motor 4 provided in the motor case 5 is connected. A motor power supply terminal board 6 for supplying power to the motor 4 is attached to the outer surface of the motor case 5 to form a drive unit B.

  For example, a small DC motor having a permanent magnet field is used as the motor 4, and driving power is supplied from a motor driving circuit 71 in the control device 7 through a motor power supply line and a terminal board 6. An opening of the pilot magnet assembly A (the left side of the outer tube 2 in the drawing) and an opening of the drive unit B (the left side of the motor case 5 in the drawing) are permanent magnet type iron removal devices (not shown). 1) is fixed to one side wall 8 of the raw material supply path where the pilot magnet assembly A is disposed at an appropriate location in the raw material supply path.

  The control device 7 is installed at an appropriate location such as a centralized monitoring board, for example, based on the motor driving current supplied to the motor 4 via the motor power feeding board 6 in addition to the motor driving circuit 71 described above. When the torque measurement circuit 72 that electrically measures the generated torque of the motor 4 or the magnetic particle adsorption amount corresponding to the measured torque corresponding value is displayed or when it is determined that the predetermined adsorption amount limit value has been reached It includes a display device 73 that performs operations such as alarm (sound) and display, and an operation device that includes an operator necessary for setting / operation of magnetic particle adsorption amount detection. In addition, about the operation of the control apparatus 7, and the structure of the panel surface for a display, it can comprise as FIG. 5 of patent document 1, for example. Further, the control device 7 may be attached to the motor case 5.

  When the permanent magnet type iron removing device (not shown) is in operation, the outer surface of the permanent magnet structure of the permanent magnet type iron removing device removes the magnetic particles (foreign matter) MP in the raw material such as synthetic resin material that passes through the raw material supply path. The magnetic particles MP are similarly adsorbed to the outer surface of the pilot magnet assembly part A (exterior tube 2) of the magnetic particle adsorption amount detection device (in addition, the magnetic particles MP are adsorbed to the raw material). “Adsorption” is also referred to as “adhesion”). Further, when the iron removal device is in operation, the rod-like permanent magnet body 1 in the pilot magnet structure A is rotated by the motor 4, and the torque generated by the motor 4 is generated by the torque measurement circuit 72 in the control device. It is electrically measured by detecting the drive current, and the magnetic particle adsorption amount corresponding to this is displayed on the display device 73.

  When the magnetic particle MP is adsorbed on the outer surface of the outer tube 2 in the pilot magnet structure A, the space between the magnetic particle MP adsorbed on the outer surface of the outer tube 2 and the rod-shaped permanent magnet body 1 inside the outer tube 2 is reduced. The magnetic force is generated in the axial direction, but this magnetic force hardly acts in the rotational direction when a normal disk-shaped electrode plate is used. In this magnetic particle adsorbing amount detection device, as shown in FIG. 2 (1), notches Ct are provided in the electrode plates Pt 1 to Ptn + 1 to generate a non-uniform magnetic flux distribution Φv in the circumferential direction, and a rod-like permanent is produced by the motor 4. Since the magnet body 1 is rotated in a predetermined direction (the direction of the arcuate arrow in the figure (clockwise direction)), the non-uniform magnetic flux distribution Φv in the circumferential direction is the same as the rod-shaped permanent magnet body 1 rotates. Rotation resistance is generated by the magnetic particles MP that rotate in the direction [the direction of the arrow on the outer side of the figure (the clockwise direction)].

  Therefore, the motor 4 generates a torque corresponding to this rotational resistance, and this torque is measured by the torque measurement circuit 72 in the control device 7. That is, this rotational resistance increases as the magnetic particles MP adsorbed on the outer tube 2 increase, and the torque generated by the motor 4 also increases accordingly. Therefore, the torque measurement circuit 72 increases the motor drive current value. And an increase in the amount of adsorption of the magnetic particles MP can be known by displaying the amount of adsorption of the magnetic particles corresponding to the detected current value on the display device.

  2 (1) is a cross-sectional view of the pilot magnet structure A in FIG. 1 as viewed from the AA plane on the right side. FIG. 2 (2) shows the electrode plates Pt1 to Ptn + 1 for reference. It is the same sectional drawing at the time of assuming that it is a perfect disk shape. Further, referring to FIG. 2, the magnetic plates MP are adsorbed by rotating the magnetic flux distribution Φv by generating a non-uniform magnetic flux distribution Φv in the circumferential direction by the pole plates Pt1 to Ptn + 1 having the notches Ct. Let us explain in more detail that can be detected quantitatively and reliably. In FIGS. 2 (1) and 2 (2), radial arrow lines indicate lines of magnetic force from the electrode plate (Pt3 in the figure).

  As shown in FIG. 1, the rod-like permanent magnet body 1 of the pilot magnet structure part A has a structure having magnetic poles (N and S poles) alternately in the length direction, and ferromagnetic pole plates Pt1 to Ptn + 1 are provided on the magnetic poles. Is used to strongly adsorb the magnetic particles MP in the raw material on the outer surface in the vicinity of the magnetic pole of the outer tube 2.

  Here, if a disk-shaped electrode plate is used for each magnetic pole, the magnetic flux density, that is, the magnetic force from the electrode plate is on the outer periphery of the outer tube 2 as indicated by the magnetic field lines indicated by radial arrows in FIG. Are uniformly distributed with a certain strength. Therefore, even if the rod-shaped permanent magnet body 1 is rotated by the motor 4 in the outer tube 2, the motor current does not change.

  That is, the magnetic force from each disk-shaped electrode plate (Pt3 in the figure) exhibits a uniform magnetic flux distribution Φu in the circumferential direction that is substantially constant and continuous in the circumferential direction. Even if it rotates in the direction of the circular arc arrow (clockwise), the force adsorbing the magnetic particles MP can be transferred continuously along the periphery of the rotating electrode plate (Pt3). Little resistance is generated. This phenomenon is exactly the same whether the magnetic particles MP are uniformly adsorbed on the outer periphery of the outer tube 2 or concentrated at one place.

  On the other hand, in this magnetic particle adsorption amount detection device, for example, as shown in FIG. 2 (1), each electrode plate (Pt3 in the figure) in which both sides of the disk are slightly cut and notched Ct is used. Thus, as shown by the magnetic field lines of the radial arrows, the distribution of the magnetic flux density in the circumferential direction is changed (Φv). In the example of the magnetic flux distribution Φv due to the shape of the notch Ct shown in the figure, the magnetic flux density in the vicinity of the outer periphery of the outer tube 2 is relatively low at the notch portion of the electrode plate Pt3 and relatively high at the arc portion. It is very high in the vicinity of the end portions (four corner portions), and the magnetic particles MP are also concentrated in the vicinity of these corner portions.

  In this magnetic particle adsorption amount detection device, the rod-shaped permanent magnet body 1 is further rotated by the motor 4 to rotate the magnetic flux distribution Φv having a change in the circumferential direction in the direction of the indicated circular arrow (clockwise). Therefore, rotation resistance (load torque) due to the magnetic particles MP is generated in the electrode plate Pt3 (that is, the rod-shaped permanent magnet body 1), and the generated torque of the motor 4 that counters the rotation resistance is measured. It is possible to know the amount of the magnetic particle MP made.

  That is, in the case of FIG. 2 (1), the magnetic flux MP, in which the circumferential magnetic flux density is increased or decreased by the notch Ct, rotates together with the rod-shaped permanent magnet body 1, so that the magnetic particle MP has this magnetic flux distribution. It tries to move following the rotation of the portion of Φv where the magnetic flux density is high and the magnetic force is strong. Here, since the magnetic particles MP are pressed against the outer tube 2 by the magnetic force directed toward the axial center of the rod-shaped permanent magnet body 1, naturally, frictional resistance (shear resistance) is generated when attempting to move. This frictional resistance replaces the rotational resistance of the rod-shaped permanent magnet body 1.

  The peripheral edges of the plate-like electrode plates Pt1 to Ptn + 1 only need to have a shape capable of generating a non-uniform magnetic flux distribution Φv in which the magnetic flux density changes in the circumferential direction, and the notch Ct in FIG. Not only the shape but also various shapes such as a triangular wave and a continuous wave can be used.

1 is an axial sectional view showing a magnetic particle adsorption amount detection device according to an embodiment of the present invention. It is a figure showing the difference in magnetic flux distribution based on the pole plate shape of a rod-shaped permanent magnet body.

Explanation of symbols

A A pilot magnet structure comprising a rod-shaped permanent magnet body 1, an outer tube 2, etc.
Pt1 to Ptn + 1 A plate-shaped electrode plate having a notch Ct,
M1-Mn permanent magnet pieces,
1a; 1b, 1c Rotating shaft and shaft end member of the rod-shaped permanent magnet body 1,
3a, 3b bearings,
B drive unit comprising motor 4, motor case 5, motor power supply terminal board 6 and the like,
4a The drive shaft of the motor 4,
7 a control device comprising a motor drive circuit 71, a torque measurement circuit 72, a display device 73, etc.
8 One side wall of the raw material supply path,
MP magnetic particles (magnetic foreign matter),
Φu, Φv Uniform magnetic flux distribution and non-uniform magnetic flux distribution in the circumferential direction.

Claims (2)

A cylindrical permanent magnet body is rotatably accommodated inside a cylindrical outer tube, and magnetic particle adsorption means for adsorbing magnetic particles on the outer surface of the outer tube by the magnetic force of the permanent magnet body;
A motor for rotating the permanent magnet body by power supply;
The torque generated by the motor is electrically measured against the rotational resistance caused by the magnetic force between the magnetic particles adsorbed on the outer tube and the permanent magnet body, and based on the measured torque An adsorption amount detecting means for determining the amount of the magnetic particles,
The permanent magnet body is formed by alternately connecting cylindrical permanent magnet pieces and disk-shaped magnetic plates,
Each magnetic electrode plate has a peripheral shape for changing the distribution of magnetic flux generated on the outer surface of the outer tube in the circumferential direction.   The adsorption amount detection means detects a drive current of the motor as an electrical measurement amount corresponding to a torque generated by the motor, and magnetic particles adsorbed on the outer tube based on the detected drive current The magnetic particle adsorption amount detection device according to claim 1, wherein an amount of the magnetic particle adsorption amount is determined.

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