Patent Description:
Grains such as cereal grains, beans, or resin pellets may be sorted into non-defective grains and defective grains based on the color or the like to remove the defective grains, or mixed foreign matters are removed in some cases.

For example, Patent Literature <NUM> discloses an optical grain sorting device in which an optical detecting unit is provided below a chute along which cereal grains flow down, a falling trajectory of grains flowing down from the chute being interposed between the chute and the optical detecting unit, an ejector nozzle is provided further below the optical detecting unit, and the optical detecting unit detects whether a falling-down grain is a non-defective grain or a defective grain, and a grain determined as a defective grain is removed from flowing-down grains with high-pressure ejected air ejected from the ejector nozzle.

The optical grain sorting device as described in Patent Literature <NUM> above removes a defective grain fallen down from the chute with ejected air. However, some grains do not fall down along a constant flying trajectory due to turbulence of the flying attitude in the air, and thus, ejected air may not hit a defective grain to cause a sorting mistake.

In order to improve sorting performance, the Applicant has filed Patent Literature <NUM>. This is a device in which a chute of a sorting unit is provided with an optical detection slit and a sorting and removal slit.

Patent Literature <NUM> discloses: Apparatus for sorting pieces of non-ferrous scrap metal into a plurality of components, each component being a particular metal type, feeds the pieces into a vertically disposed sorting zone. The pieces fall down a steeply inclined guide member under the influence of gravity and they pass a pair of timing devices which are spaced apart along the guide member, each timing device being a light source on one side of the path of the pieces and a light detector on the other side. The timing devices provide signals representing not only timing but also size and velocity. The pieces then pass an x-ray analysis system including a source of high energy rays to induce x-ray fluorescence and a detector to detect this fluorescence. The detector provides signals indicating the metal type for each piece of scrap. The pieces then fall past a plurality of blast nozzles spaced apart along the guide member. Each nozzle has a control which turns on a flow of fluid such as air through the nozzle to deflect a particular piece into a specific deflection path. Each piece is thus directed into a deflection path for a specific component.

Patent Literature <NUM> discloses an optical sorter intended to simply calculate the positional accuracy of a constituent member attached to a frame without welding distortion occurring in the frame.

The optical sorting device as in Patent Literature <NUM> requires an optical detecting unit to be provided in correspondence to the optical detection slit of the chute, and an ejector nozzle to be provided in correspondence to the sorting and removal slit further below the optical detection slit. This results in size increase as a whole, burdensome assembling, and unsuitableness to manual or robot mass production. In particular, in such a case of attaching the device to a rice husking machine, such problems are pronounced.

In addition, it is required to minimize the distance between the optical detection slit and the sorting and removal slit, achieve size reduction, and improve sorting accuracy.

Furthermore, in the optical sorting device as in Patent Literature <NUM>, the optical detection slit on the chute is formed. Thus, dust and the like including dust and powder particles produced by flowing-down grains could enter the rear surface side of the chute through the optical detection slit, and adhere to equipment installed on the rear surface side of the chute to cause adverse effects. In particular, in such a case of attaching the device to a rice husking machine, optical equipment is likely to degrade significantly in performance due to adhesion of dust and the like, and a sorting mistake is likely to occur.

In addition, fitting a translucent plate in the optical detection slit to prevent dust and the like from entering is also conceivable. However, when dust and the like adhere to the translucent plate, translucency may degrade. Furthermore, when trying to remove dust and the like adhering to the translucent plate, it is necessary to stop flow-down of grains so as to operate removing means on the front surface side of the chute, which interrupts a sorting operation.

An objective to be achieved by the present invention is to provide an optical sorting device which is compact, easy to assemble, and suited to mass production. An objective to be achieved by the present invention is to provide an optical sorting device which minimizes the distance between the optical detection slit and the sorting and removal slit, has high sorting accuracy, and is compact. In addition, an objective to be achieved by the present invention is to provide an optical sorting device which prevents dust and the like produced on the front surface side of the chute from entering the rear surface side through the optical detection slit without providing the optical detection slit with a translucent plate, so that a sorting mistake is less likely to occur.

According to the present invention, there is provided an optical sorting device as defined in the claims. A rice husking and sorting machine including the optical sorting device is provided also.

Since the present invention blows air to an object to be sorted flowing down along a stable trajectory on the front surface of the chute through the sorting and removal slit, an object to be sorted that should be removed can be reliably hit with ejected air without being affected by turbulence of an air flow or the like, a sorting mistake is less likely to occur, and the accuracy is improved.

Since the rear-side illuminating portion and the ejector nozzle are attached to a single base member, the rear-side illuminating portion and the ejector nozzle can be installed easily at the same time merely by attaching the base member. As a result, manual or robot mass production can be easily performed. In addition, since the device is reduced in size, and the distance between the rear-side illuminating portion and the ejector nozzle, that is, the distance between the optical detection slit and the sorting and removal slit is reduced, the trajectory of mixed grains after passing through the light detection slit and before reaching the sorting and removal slit is less likely to change, and the sorting accuracy increases.

Additionally, since the base member or the rear-side illuminating portion includes a positioning protrusion to be inserted into the optical detection slit to position the base member to the chute, positioning can be easily performed at the time of attachment.

Additionally, since the base member or the ejector nozzle includes a positioning protrusion to be inserted into the sorting and removal slit to position the base member to the chute, positioning can be easily performed at the time of attachment.

Additionally, by storing the front-side illuminating portion, the light receiving part, and the optical path in the front-side housing, assembling is further facilitated, and the front-side illuminating portion, the light receiving part, and the optical path are protected from dust and the like.

Additionally, if the base member serves as the rear-side housing, and the rear-side illuminating portion, the ejector nozzle, and the manifold are stored in the rear-side housing, the device can further be reduced in size, and dust and the like are less likely to adhere to the rear-side illuminating portion.

Additionally, by extending the projecting piece to the outer surface of the rear-side housing, and providing the electromagnetic valve with an engaging stop to be brought into snap engagement with the projecting piece, the electromagnetic valve can be easily attached to the rear-side housing.

Additionally, if the ejector nozzle is coupled to the manifold and the electromagnetic valve installed outside the rear-side housing with an air hose, a manifold and an electromagnetic valve which are commercially available and common can be used.

Additionally, since the rear-side illuminating portion has the light source and the reflector that reflects light radiated from the light source toward the optical detection slit, and the light source, the reflector, and the ejector nozzle are arranged in the order presented from the upstream side of the chute, the distance between the optical detection slit and the sorting and removal slit can be reduced further, and size reduction and increased sorting accuracy can be achieved.

In addition, since dust and the like produced from objects to be sorted flowing down on the front surface of the chute do not enter the rear surface side of the chute without providing the optical detection slit with a translucent plate, dust and the like are less likely to adhere to equipment installed on the rear surface side of the chute. It is possible to prevent dust from adhering particularly to the rear-side optical inspection part, prevent performance from significantly degrading, and prevent a sorting mistake from occurring.

In addition, since the air curtain prevents dust and the like from entering, translucency is not lost as in a device in which dust and the like are blocked by a translucent plate.

Although a device that transmits light through a translucent plate requires the sorting operation to be interrupted when removing dust and the like, the present invention eliminates such a necessity.

Additionally, since the slit air nozzle is arranged such that air of the air curtain is ejected from the upstream side toward the downstream side of the chute, flow-down of the objects to be sorted can be less affected even in a case in which air of the air curtain comes out of the optical detection slit to the front surface side of the chute.

Additionally, since the ejector unit has the ejector nozzle capable of ejecting air to the objects to be sorted on the downstream side of the optical detection slit, the air discharge part is provided on the downstream side of the air curtain ejected from the slit air nozzle, and the surface of the air discharge part opposite to the slit air nozzle is inclined toward the downstream side with distance from the optical detection slit, air of the air curtain efficiently flows toward the air discharge part without flowing out of the optical detection slit to the front surface side of the chute. Thus, air ejection from the ejector nozzle arranged on the downstream side is not affected.

Additionally, since the rear-side optical inspection part includes the rear translucent plate that blocks circulation of air between the slit air nozzle and at least one of the illuminating portion and the light receiving portion that the rear-side optical inspection part has, the rear-side optical inspection part can be protected from dust and the like.

Additionally, since the rear translucent plate air nozzle capable of forming the air curtain that prevents dust and the like from adhering to the rear translucent plate is provided for the rear-side optical inspection part on the slit air nozzle side of the rear translucent plate, dust and the like can be prevented from adhering to the rear translucent plate.

Additionally, the rear-side optical inspection part includes the rear translucent plate that blocks circulation of air between the slit air nozzle and at least one of the illuminating portion and the light receiving portion that the rear-side optical inspection part has, the rear translucent plate air nozzle capable of forming the air curtain that prevents dust and the like from adhering to the rear translucent plate is provided for the rear translucent plate on the slit air nozzle side, the air discharge part is provided on the downstream side of the air curtain ejected from the rear translucent plate air nozzle, and the air discharge part also discharges the air curtain ejected from the slit air nozzle. Thus, the air discharge part can be shared, and a compact configuration can be achieved.

Additionally, the optical inspection unit has the front-side optical inspection part having the illuminating portion that emits light toward the optical detection slit and the light receiving portion that receives at least one of transmitted light and reflected light from the sorting unit of the light emitted from the illuminating portion, at least one of the illuminating portion and the light receiving portion being arranged on the front surface side of the chute, the front-side optical inspection part includes the front translucent plate that blocks circulation of air between the chute and at least one of the illuminating portion and the light receiving portion that the front-side optical inspection part has, and the front translucent plate air nozzle capable of forming the air curtain that prevents dust and the like from adhering to the front translucent plate is provided for the front translucent plate on the chute side. Thus, the front-side optical inspection part can be protected from dust and the like, and dust and the like can be prevented from adhering to the front translucent plate.

Additionally, since the front translucent plate air nozzle is arranged such that the formed air curtain is ejected to be gradually distant from the flowing down direction of the objects to be sorted, flowing down of the objects to be sorted on the chute is not affected.

Hereinafter, embodiments of the present invention will be described with reference to the drawings or the like. Note that the present invention is obviously not limited to the embodiments.

Hereinafter, a first embodiment of the present invention will be described along with <FIG>.

<FIG> is a cross-sectional view of a sorting machine in the first embodiment, <FIG> is a cross-sectional view of an optical sorting device in the first embodiment, <FIG> is a perspective view of a chute in the first embodiment, and <FIG> is a magnified cross-sectional view of an essential part of the optical sorting device in the first embodiment.

In the first embodiment, as shown in <FIG>, an optical sorting device <NUM> is mounted on a sorting unit <NUM> of a rice husking and sorting machine not shown. The sorting unit <NUM> is a secondary sorting unit installed adjacent to a downstream side of a rice husking unit not shown.

In the rice husking unit, unhusked rice is separated into the husk and brown rice, and the husk is primarily sorted. Mixed grains (objects to be sorted) composed of brown rice still containing foreign matters such as husks primarily sorted are sent to the sorting unit <NUM>, and only the foreign matters are sorted and removed from the mixed grains by the optical sorting device <NUM>.

A raw material hopper <NUM> to which mixed grains are delivered from the rice husking unit is provided at a lower part of the sorting unit <NUM>. A storage tank <NUM> is installed at an upper part of the optical sorting device <NUM> above the sorting unit <NUM>. The mixed grains delivered into the raw material hopper <NUM> are lifted by a grain lifting unit <NUM> to the storage tank <NUM>.

The mixed grains lifted to the storage tank <NUM> are supplied to an upper end of a chute <NUM> via a rotary valve <NUM>. A brown rice discharge channel <NUM> that discharges brown rice not eliminated by an ejector unit <NUM> of the optical sorting device <NUM> is coupled to a lower part of the chute <NUM>. A foreign matter discharge channel <NUM> that discharges foreign matters eliminated by the ejector unit <NUM> of the optical sorting device <NUM> is also coupled to the lower part of the chute <NUM>.

As shown in <FIG>, the optical sorting device <NUM> includes the inclined chute <NUM> on which mixed grains flow down on its front surface. The optical sorting device <NUM> includes an optical inspection unit <NUM> arranged opposite to the front surface side and the rear surface side of the chute <NUM>. The optical sorting device <NUM> includes the ejector unit <NUM> that, based on an inspection result obtained by the optical inspection unit <NUM>, determines a foreign matter a and a brown rice b among mixed grains, and eliminates only the foreign matter a from the mixed grains.

As shown in <FIG>, an optical detection slit <NUM> is formed on the chute <NUM> in a manner orthogonally crossing the flowing down direction of the mixed grains. A sorting and removal slit <NUM> is formed on the chute <NUM> on a downstream side of the optical detection slit <NUM> in a manner orthogonally crossing the flowing down direction of the mixed grains. The optical detection slit <NUM> and the sorting and removal slit <NUM> are formed at close positions.

The widths of the optical detection slit <NUM> and the sorting and removal slit <NUM> are set in accordance with the size and weight of the mixed grains flowing down on the chute <NUM>, a removing capability of the ejector unit <NUM>, and the like.

As shown in <FIG>, the optical inspection unit <NUM> includes an illuminating part <NUM> that emits light to mixed grains flowing down on the front surface of the chute <NUM>. The optical inspection unit <NUM> includes a light receiving part <NUM> such as a CCD camera that receives transmitted light and reflected light from the mixed grains to which light has been emitted from the illuminating part <NUM>. The optical inspection unit <NUM> includes an optical path <NUM> that sends the transmitted light and the reflected light to the light receiving part <NUM>.

The optical path <NUM> is composed of a plurality of reflective plates and a lens, and the light receiving part <NUM> and the optical path <NUM> are stored integrally in a front-side housing <NUM> together with a front-side illuminating portion 14b.

The front-side housing <NUM> is arranged on the front surface side of the chute <NUM> at a position opposite to the optical detection slit <NUM>, and the front-side illuminating portion 14b faces the optical detection slit <NUM>.

Then, light from the front-side illuminating portion 14b is emitted to a grain (the foreign matter a or the brown rice b) passing through the optical detection slit <NUM>, and reflected light from the grain reaches the light receiving part <NUM> through the optical path <NUM>.

As shown in <FIG>, the illuminating part <NUM> includes a rear-side illuminating portion 14a installed on the rear surface side of the chute <NUM>, and the front-side illuminating portion 14b installed on the front surface side of the chute <NUM>.

The rear-side illuminating portion 14a includes a light diffuser plate <NUM> which is an opaque white translucent plate, a light source <NUM> such as an LED, and the reflector <NUM> which is a concave mirror.

The front-side illuminating portion 14b is a light source such as an LED.

The light diffuser plate <NUM> is provided with its planar direction being in parallel to the flowing down direction on the chute <NUM>.

The light source <NUM> is provided directly above and in close contact with an ejector nozzle <NUM>, and is arranged so as to radiate light in the direction opposite to the flowing down direction on the chute <NUM>. The light source <NUM> is in the form of a flat plate, and arranged with its planar direction being in parallel to an ejecting direction in which the ejector nozzle <NUM> extends.

The reflector <NUM> reflects light radiated from the light source <NUM> toward the light diffuser plate <NUM>.

With such an arrangement, the ejector nozzle <NUM> and the rear-side illuminating portion 14a can be brought close to each other, and the optical detection slit <NUM> and the sorting and removal slit <NUM> can be brought close to each other.

The rear-side illuminating portion 14a includes an opening member 14a1 through which light is output to flowing-down mixed grains. The opening member 14a1 forms a positioning protrusion that protrudes from a rear-side housing <NUM> which is a base member. The light diffuser plate <NUM> is provided on the light source <NUM> side of the opening member 14a1.

When the opening member 14a1 which is the positioning protrusion is inserted into the optical detection slit <NUM>, the rear-side housing <NUM> to which the rear-side illuminating portion 14a has been attached is positioned on the chute <NUM>.

In the present embodiment, the positioning protrusion is the opening member 14a1 of the rear-side illuminating portion 14a, but a similar component may be provided on the portion of the rear-side housing <NUM> to which the rear-side illuminating portion 14a is to be attached to configure a positioning protrusion on the base member.

The ejector unit <NUM> includes a plurality of ejector nozzles <NUM>, a manifold <NUM> that distributes high-pressure air to the ejector nozzles <NUM>, and an electromagnetic valve <NUM> that controls air ejection from the ejector nozzles <NUM>.

An air supply pipe <NUM> is connected to the manifold <NUM>, and high-pressure air is supplied from a compressor or the like to the manifold <NUM> through the air supply pipe <NUM>.

In addition, the electromagnetic valve <NUM> is connected to the light receiving part <NUM> of the optical inspection unit <NUM> with a valve driving circuit substrate <NUM> and a signal processing substrate <NUM> interposed therebetween (<FIG>).

A leading end 22a of the ejector nozzle <NUM> forms the positioning protrusion that protrudes from the rear-side housing <NUM> which is the base member.

When the leading end 22a of the ejector nozzle <NUM> which is the positioning protrusion is inserted into the sorting and removal slit <NUM>, the rear-side housing <NUM> to which the ejector unit <NUM> has been attached is positioned on the chute <NUM>.

In the present embodiment, the positioning protrusion is the leading end 22a of the ejector nozzle <NUM>, but a similar component may be provided on the portion of the rear-side housing <NUM> to which the ejector nozzle <NUM> is to be attached to configure a positioning protrusion on the base member.

The box-like rear-side housing <NUM> is attached as the base member to the rear surface side of the chute <NUM>. The rear-side illuminating portion 14a, the ejector nozzles <NUM>, and the manifold <NUM> are integrally stored in the rear-side housing <NUM>. In other words, the rear-side illuminating portion 14a, the ejector nozzles <NUM>, and the manifold <NUM> can be unitized by the rear-side housing <NUM> which is the base member.

A front surface of the rear-side housing <NUM> opposite to the rear surface of the chute <NUM> is open so as to allow the opening member 14a1 of the rear-side illuminating portion 14a and the leading end 22a of the ejector nozzle <NUM> which serve as the positioning protrusions to protrude.

The back surface of the rear-side housing <NUM> is provided with openings for the manifold <NUM> and the electromagnetic valve <NUM> to communicate with each other and the ejector nozzle <NUM> and the electromagnetic valve <NUM> to communicate with each other.

A hook part <NUM> is formed at one end of the back surface of the rear-side housing <NUM>, and a projecting piece <NUM> is extended at the other end of the back surface.

A flange <NUM> is formed at one end of the front surface of the electromagnetic valve <NUM>, and a locking stop <NUM> to be brought into snap engagement with the projecting piece <NUM> is provided on the other end of the front surface.

The electromagnetic valve <NUM> is inclined to insert the flange <NUM> into the hook part <NUM>, and then the electromagnetic valve <NUM> is turned to bring the locking stop <NUM> into snap engagement with the projecting piece <NUM>. The electromagnetic valve <NUM> can thereby be attached to the back surface (outer surface) of the rear-side housing <NUM> with a single touch to be fitted over the manifold <NUM>.

At replacement or the like of the electromagnetic valve <NUM>, the electromagnetic valve <NUM> can be easily detached from the rear-side housing <NUM> by pivoting the locking stop <NUM> to be moved away from the projecting piece <NUM>.

Assembling on the rear side of the chute <NUM> is performed in the following manner.

The rear-side illuminating portion 14a, the ejector nozzles <NUM>, and the manifold <NUM> are stored in the rear-side housing <NUM> to be unitized. The opening member 14a1 of the rear-side illuminating portion 14a and the leading end 22a of the ejector nozzle <NUM> which serve as the positioning protrusions protrude from the front surface of the rear-side housing <NUM>.

The opening member 14a1 of the rear-side illuminating portion 14a and the leading end 22a of the ejector nozzle <NUM> which serve as the positioning protrusions are respectively inserted into the optical detection slit <NUM> and the sorting and removal slit <NUM> to be positioned, so that the rear-side housing <NUM> is attached to the rear surface of the chute <NUM>.

The rear-side housing <NUM> is installed such that the opening member 14a1 of the rear-side illuminating portion 14a faces the optical detection slit <NUM>, and the leading end 22a of the ejector nozzle <NUM> faces the sorting and removal slit <NUM>.

The rear-side housing <NUM> is further fixed by engaging the stop with the rear surface of the chute <NUM> or by means of a fixture such as a screw.

The electromagnetic valve <NUM> is attached to the back surface of the rear-side housing <NUM> at appropriate timing.

The rear-side housing <NUM>, the valve driving circuit substrate <NUM>, the signal processing substrate <NUM>, and a power source <NUM> that drives the optical sorting device <NUM> are stored in a box <NUM>, and the box <NUM> is installed on the rear surface side of the chute <NUM> (<FIG> and <FIG>).

Light from the rear-side illuminating portion 14a is emitted to a grain passing above the optical detection slit <NUM> through the optical detection slit <NUM>, and light transmitted through the grain reaches the light receiving part <NUM> through the optical path <NUM>.

Light from the front-side illuminating portion 14b is emitted to the grain passing above the optical detection slit <NUM>, and light reflected by the grain reaches the light receiving part <NUM> through the optical path <NUM>.

A light reception signal of the light receiving part <NUM> is sent to the signal processing substrate <NUM>. A signal level of the light reception signal is compared with a threshold value in the signal processing substrate <NUM>, and it is determined whether the grain is the foreign matter a or the brown rice b.

A determination result obtained by the signal processing substrate <NUM> is transmitted to the valve driving circuit substrate <NUM>. Opening/closing of the electromagnetic valve <NUM> is controlled by the valve driving circuit substrate <NUM>.

In a case in which the grain is determined as the foreign matter a, high-pressure air is ejected from one of the ejector nozzles <NUM> selected by opening/closing control of the electromagnetic valve <NUM> when the grain passes through the sorting and removal slit <NUM>. The foreign matter a is eliminated from the front surface of the chute <NUM> with the high-pressure air ejected from the ejector nozzle <NUM>. The eliminated foreign matter a is discharged to the foreign matter discharge channel <NUM>.

The brown rice b not having been eliminated is sent to the next step through the brown rice discharge channel <NUM>.

Hereinafter, a second embodiment according to the present invention will be described along with <FIG>. Note that description of points similar to those of the first embodiment will be omitted, and different points will mainly be described.

In the second embodiment, the light source <NUM> of the rear-side illuminating portion 14a is installed oppositely so as to radiate light toward the ejector nozzles <NUM>.

The reflector <NUM> is provided directly above and in close contact with the ejector nozzles <NUM>.

Light radiated from the light source <NUM> is reflected by the reflector <NUM> toward the light diffuser plate <NUM>, and emitted to mixed grains through the optical detection slit <NUM>. In other words, the light source <NUM>, the reflector <NUM>, and the ejector nozzles <NUM> are arranged in an order presented from the upstream side of the chute <NUM> in the flowing down direction on the chute <NUM>.

The reflector <NUM> that can have a smaller space (height in the flowing down direction on the chute <NUM>) than the light source <NUM> is brought into close contact with the ejector nozzles <NUM> to arrange the light source <NUM> on the upstream side of the reflector <NUM> in the flowing down direction on the chute <NUM>. The opening member 14a1 of the rear-side illuminating portion 14a can thereby be brought closer to the ejector nozzles <NUM>, so that the distance between the optical detection slit <NUM> and the sorting and removal slit <NUM> can be reduced further. Thus, sorting accuracy can be improved.

Hereinafter, a third embodiment according to the present invention will be described along with <FIG>. Note that description of points similar to those of the first embodiment or the second embodiment will be omitted, and different points will mainly be described.

In the third embodiment, the rear-side illuminating portion 14a and the ejector nozzles <NUM> are installed in the rear-side housing <NUM>, and the manifold <NUM> and the electromagnetic valve <NUM> are installed outside the rear-side housing <NUM>. Specifically, the manifold <NUM> and the electromagnetic valve <NUM> are provided outside the box <NUM>.

The electromagnetic valve <NUM> is fitted over the manifold <NUM>, and coupled to the ejector nozzles <NUM> with an air hose <NUM>.

It is not necessary to provide the rear-side housing <NUM> with a hook part, a projecting piece, or the like for attaching the electromagnetic valve <NUM>.

Hereinafter, a fourth embodiment of the present invention will be described along with <FIG>, and <FIG>.

<FIG> is a cross-sectional view of a sorting machine in the fourth embodiment, <FIG> is a perspective view of a chute in the fourth embodiment, <FIG> is a cross-sectional view of an optical sorting device in the fourth embodiment, and <FIG> is a magnified cross-sectional view of an essential part of the optical sorting device in the fourth embodiment.

In the fourth embodiment, as shown in <FIG>, the optical sorting device <NUM> is mounted on a sorting unit of a rice husking and sorting machine not shown. The sorting unit <NUM> is a secondary sorting unit installed adjacent to the downstream side of a rice husking unit not shown.

Unhusked rice is separated into the husk and brown rice in the rice husking unit, and the husk is primarily sorted. Mixed grains (objects to be sorted) composed of brown rice still containing foreign matters such as husks primarily sorted are sent to the sorting unit <NUM>, and only the foreign matters are sorted and removed from the mixed grains by the optical sorting device <NUM>.

A raw material hopper <NUM> to which mixed grains are delivered from the rice husking unit is provided at a lower part of the sorting unit <NUM>. A storage tank <NUM> is installed at an upper part of the optical sorting device <NUM> above the sorting unit <NUM>. The mixed grains delivered into the raw material hopper <NUM> are lifted by the grain lifting unit <NUM> to the storage tank <NUM>.

The mixed grains lifted to the storage tank <NUM> are supplied to an upper end of a chute <NUM> via a rotary valve <NUM>. A brown rice discharge channel <NUM> that discharges brown rice not eliminated by an ejector unit <NUM> of the optical sorting device <NUM> is coupled to the lower part of the chute <NUM>. A foreign matter discharge channel <NUM> that discharges foreign matters eliminated by the ejector unit <NUM> of the optical sorting device <NUM> is also coupled to the lower part of the chute <NUM>.

The optical sorting device <NUM> includes the inclined chute <NUM> on which mixed grains flow down on its front surface. The optical sorting device <NUM> includes an optical inspection unit <NUM> that performs optical inspection to the mixed grains flowing down on the front surface of the chute <NUM>. The optical sorting device <NUM> includes the ejector unit <NUM> that, based on an inspection result obtained by the optical inspection unit <NUM>, determines a foreign matter a and a brown rice b among mixed grains, and eliminates only the foreign matter a from the mixed grains.

A box 6a that stores a signal processing substrate, an electromagnetic valve driving circuit substrate, a power source, and the like, neither shown, is attached to the rear surface of the chute <NUM>.

As shown in <FIG>, the optical detection slit <NUM> is formed on the chute <NUM> in a manner orthogonally crossing the flowing down direction of the mixed grains. The sorting and removal slit <NUM> is formed on the chute <NUM> on the downstream side of the optical detection slit <NUM> in the manner orthogonally crossing the flowing down direction of the mixed grains. The optical detection slit <NUM> and the sorting and removal slit <NUM> are formed at close positions.

As shown in <FIG>, the optical inspection unit <NUM> includes a rear-side optical inspection part 7a and a front-side optical inspection part 7b installed on the rear surface side and the front surface side of the chute <NUM> at positions with the optical detection slit <NUM> interposed therebetween.

The rear-side optical inspection part 7a includes a rear-side illuminating portion 114a such as an LED, a rear-side light receiving portion 115a such as a CCD camera, a rear-side background illuminating portion 116a to be opposite to the front-side optical inspection part 7b, and a rear-side optical path 117a having a plurality of reflective plates 117a1 and a lens 117a2, and is stored in a rear-side housing <NUM>.

As shown in <FIG> and <FIG>, a rear-side opening <NUM> through which light passes is formed in the rear-side housing <NUM>. The rear-side housing <NUM> is attached to the rear surface side of the chute <NUM> in a manner that the rear-side opening <NUM> conforms to the optical detection slit <NUM>.

The rear-side opening <NUM> is formed across the entire widthwise length of the optical detection slit <NUM>, and light radiated from the rear-side illuminating portion 114a is emitted to a grain passing above the optical detection slit <NUM> (the foreign matter a or the brown rice b) through the rear-side opening <NUM> and the optical detection slit <NUM>.

As shown in <FIG>, an ejector nozzle <NUM> of the ejector unit <NUM> is incorporated in the rear-side housing <NUM>. A leading end 121a of the ejector nozzle <NUM> is exposed at the outer surface of the rear-side housing <NUM> on a downstream side of the rear-side opening <NUM> on the chute <NUM> to face the sorting and removal slit <NUM>. Specifically, the leading end 121a of the ejector nozzle <NUM> protrudes from the surface of the rear-side housing <NUM> on the rear surface side of the chute <NUM> to form a positioning protrusion.

When the leading end 121a of the ejector nozzle <NUM> which serves as the positioning protrusion is inserted into the sorting and removal slit <NUM>, the rear-side housing <NUM> to which the ejector unit <NUM> has been attached is positioned on the chute <NUM>.

As shown in <FIG> and <FIG>, an air chamber <NUM> to which air is supplied via an air supply pipe <NUM>' is formed in the rear-side housing <NUM> on the upstream side of the rear-side opening <NUM> on the chute <NUM>. A slit air nozzle <NUM> that ejects air from the air chamber <NUM> toward the rear-side opening <NUM> is disposed. An air curtain <NUM> can be formed by air ejected from this slit air nozzle <NUM>.

The air discharge part <NUM> is formed so as to open to the outside of the rear-side housing <NUM> on the downstream side with the interposition of the rear-side opening <NUM> of the rear-side housing <NUM> and on the downstream side of the air curtain <NUM> ejected from the slit air nozzle <NUM>.

The effective air curtain <NUM> is formed by air ejected from the slit air nozzle <NUM> and discharged from the air discharge part <NUM>. This can prevent dust and the like from entering the rear-side optical inspection part 7a through the optical detection slit <NUM>.

Air of the air curtain <NUM> is arranged so as to be ejected from the upstream side toward the downstream side of the chute <NUM> on the rear surface side of the optical detection slit <NUM>. Accordingly, even in a case in which air of the air curtain <NUM> comes out to the front surface side of the chute <NUM> from the optical detection slit <NUM>, an influence upon flow-down of mixed grains can be reduced.

As shown in <FIG>, a surface 124a of the air discharge part <NUM> opposite to the slit air nozzle <NUM> is inclined to the downstream side with distance from the optical detection slit <NUM>. The air curtain <NUM> ejected from the slit air nozzle <NUM> thereby hits the opposite surface to be efficiently guided to a discharge port of the air discharge part <NUM>. Thus, air of the air curtain <NUM> flows toward the discharge port of the air discharge part <NUM> without flowing out to the front surface side of the chute <NUM> through the optical detection slit <NUM>. Therefore, air ejection from the ejector nozzle <NUM> arranged on the downstream side is not affected.

As shown in <FIG>, the front-side optical inspection part 7b includes a front-side illuminating portion 114b such as an LED, a front-side light receiving portion 115b such as a CCD camera, a front-side background illuminating portion 116b to be opposite to the rear-side optical inspection part 7a, and a front-side optical path 117b having a plurality of reflective plates 117b1 and a lens 117b2, and is stored in a front-side housing <NUM>.

A front-side opening <NUM> through which light passes is formed in the front-side housing <NUM>. The front-side housing <NUM> is installed on the front surface side of the chute <NUM> in a manner that the front-side opening <NUM> conforms to the optical detection slit <NUM>.

The front-side opening <NUM> is formed across the entire widthwise length of the chute <NUM>, and light radiated from the front-side illuminating portion 114b is emitted to a grain (the foreign matter a or the brown rice b) passing above the optical detection slit <NUM> through the front-side opening <NUM>.

Light from the rear-side illuminating portion 114a is emitted from the rear surface side to the grain passing above the optical detection slit <NUM> through the rear-side opening <NUM> and the optical detection slit <NUM> of the rear-side housing <NUM>. Light from the front-side illuminating portion 114b is emitted from the front surface side to the grain passing above the optical detection slit <NUM> through the front-side opening <NUM> of the front-side housing <NUM>.

Light reflected by the grain and light transmitted through the grain advance into the rear-side housing <NUM> and the front-side housing <NUM> through the rear-side opening <NUM> and the front-side opening <NUM>, and are received by the rear-side light receiving portion 115a and the front-side light receiving portion 115b via the rear-side optical path 117a and the front-side optical path 117b.

Light reception signals received by the rear-side light receiving portion 115a and the front-side light receiving portion 115b are sent to a signal processing substrate not shown but stored in the box 6a. A signal level of the light reception signals is compared with a threshold value in the signal processing substrate, and it is determined whether the grain is the foreign matter a or the brown rice b.

A determination result obtained by the signal processing substrate is transmitted to a valve driving circuit substrate not shown but stored in the box 6a. Opening/closing of an electromagnetic valve not shown of the ejector unit <NUM> is controlled by the valve driving circuit substrate.

In a case in which the grain is determined as the foreign matter a, high-pressure air is ejected from the ejector nozzle <NUM> selected by opening/closing control of electromagnetic valve when the grain passes through the sorting and removal slit <NUM>. The foreign matter a is eliminated from the front surface of the chute <NUM> with the high-pressure air ejected from the ejector nozzle <NUM>. The eliminated foreign matter a is discharged through the foreign matter discharge channel <NUM>.

A grain which is the brown rice b not having been eliminated is sent to the next step through the brown rice discharge channel <NUM>.

Since the optical detection slit <NUM> is blocked by the air curtain <NUM>, dust and the like produced from mixed grains flowing down on the front surface of the chute <NUM> neither enter the rear surface side of the chute <NUM> nor adhere to the rear-side optical inspection part 7a in the rear-side housing <NUM> through the rear-side opening <NUM>.

Hereinafter, a fifth embodiment according to the present invention will be described along with <FIG>. Note that description of points similar to those of the fourth embodiment will be omitted, and different points will mainly be described.

In the fifth embodiment, the rear-side optical inspection part 7a includes a rear translucent plate <NUM> that blocks circulation of air between the slit air nozzle <NUM> and the rear-side illuminating portion 114a, the rear-side background illuminating portion 116a, the rear-side optical path 117a, and the rear-side light receiving portion 115a.

Specifically, in the rear-side housing <NUM>, the rear translucent plate <NUM> is fitted on the farther side of the rear-side opening <NUM> so as to cross the internal space. The rear-side opening <NUM> and the rear-side illuminating portion 114a, the rear-side background illuminating portion 116a, the rear-side optical path 117a, and the rear-side light receiving portion 115a of the rear-side optical inspection part 7a are blocked by the rear translucent plate <NUM>.

Accordingly, the rear-side optical inspection part 7a is strictly protected even if dust and the like fly due to the air curtain <NUM>.

A rear translucent plate air nozzle <NUM> is provided on the slit air nozzle <NUM> side on the chute <NUM> side of the rear translucent plate <NUM> and on the upstream side. The rear translucent plate air nozzle <NUM> is provided to communicate with the air chamber <NUM>. The rear translucent plate air nozzle <NUM> is arranged so as to eject air along the rear translucent plate <NUM>, and this air allows the air curtain to be formed along the rear translucent plate <NUM>.

Therefore, dust and the like can be prevented from adhering to the rear translucent plate <NUM>.

This air curtain is discharged through the opening of the air discharge part <NUM>. In other words, this air discharge part <NUM> can discharge both the air curtain ejected from the rear translucent plate air nozzle <NUM> and the air curtain <NUM> ejected from the slit air nozzle <NUM>.

Therefore, the air discharge part can be used in common, and a compact configuration can be achieved.

The front-side optical inspection part 7b includes a front translucent plate <NUM> that blocks circulation of air between the chute <NUM> and the front-side illuminating portion 114b, the front-side background illuminating portion 116b, the front-side optical path 117b, and the front-side light receiving portion 115b.

Specifically, the front translucent plate <NUM> is fitted in the front-side opening <NUM> of the front-side housing <NUM>. The front surface side of the chute <NUM> and the front-side illuminating portion 114b, the front-side background illuminating portion 116b, the front-side optical path 117b, and the front-side light receiving portion 115b are blocked by the front translucent plate <NUM>.

Dust and the like produced on the front surface side of the chute <NUM> are thereby prevented from entering the inside of the front-side housing <NUM>, and the front-side optical inspection part 7b is strictly protected.

A front translucent plate air nozzle <NUM> is provided on the chute <NUM> side of the front translucent plate <NUM> and on the upstream side. The front translucent plate air nozzle <NUM> is provided to communicate with an air chamber <NUM>. An air supply pipe <NUM>' is coupled to the air chamber <NUM>. The front translucent plate air nozzle <NUM> is arranged so as to eject air along the front translucent plate <NUM>, and this air allows an air curtain to be formed along the front translucent plate <NUM>.

Therefore, dust and the like can be prevented from adhering to the front translucent plate <NUM>.

The direction in which the air curtain formed by the front translucent plate <NUM> and the front translucent plate air nozzle <NUM> is formed is provided so as to be gradually depart from the flowing down direction of mixed grains flowing down on the chute <NUM>. In other words, a space <NUM> between the front translucent plate <NUM> and the chute <NUM> is formed so as to be wider toward the downstream. Thus, the air curtain formed by the front translucent plate air nozzle <NUM> does not affect flowing down of mixed grains on the chute.

In addition, a lower part of the space <NUM> forms an air discharge part for the air curtain formed by the front translucent plate air nozzle <NUM>.

The present invention is not limited to the above-described embodiments. For example, the following are also included.

In the present embodiment, the optical sorting device sorts foreign matters such as husks and brown rice, but can also be used for sorting other cereals, beans, resin pellets, or the like.

In the present embodiment, the rear-side illuminating portion does not include an optical path or a light receiving portion, but this is not a limitation. The rear-side illuminating portion may include an optical path and a light receiving portion.

In the present embodiment, the base member is the box-like rear-side housing, but may be a member having a plate-like shape on which the rear-side illuminating portion and the ejector nozzle can be placed for unitization, rather than storing components inside.

In the first and second embodiments, the projecting piece and the engaging stop are provided only at one-side ends of the rear-side housing and the electromagnetic valve, but, a projecting piece and an engaging stop to be brought into snap engagement with the projecting piece may be provided on each side end. In addition, the rear-side housing and the electromagnetic valve can also be joined with another locking instrument.

In the present embodiment, the positioning protrusions are provided so as to be inserted into both the optical detection slit <NUM> and the sorting and removal slit <NUM>, but this is not a limitation.

The present embodiment is configured such that the positioning protrusions are inserted into the optical detection slit <NUM> and the sorting and removal slit <NUM> when positioning the base member on the chute, but this is not a limitation. For example, the rear-side housing <NUM> is attached to a place other than the slits on the rear surface of the chute <NUM> by hooking a stop or by means of a fixture such as a screw, but may be automatically aligned in position by aligning a stop-engaging position or a hole through which the fixture insertion is to be inserted.

In the present embodiment, both the front-side optical inspection part and the rear-side optical inspection part include light source, optical paths, and light receiving portions, but this is not a limitation. For example, one of them may include a light source portion, and the other may include a light receiving portion alone.

In the present embodiment, air is ejected from the ejector nozzle installed on the rear surface side of the chute to the front surface side of the chute through the sorting and removal slit, but, air may be ejected to objects to be sorted released from the lower end of the chute without providing the sorting and removal slit. In this case, air may be ejected from the upper side toward the lower side.

Claim 1:
An optical sorting device (<NUM>) comprising:
a chute (<NUM>) having an optical detection slit (<NUM>) and a sorting and removal slit (<NUM>) arranged on a downstream side of the optical detection slit, an object to be sorted flowing down on a front surface of the chute;
an optical inspection unit (<NUM>) having an illuminating part (<NUM>) having a rear-side illuminating portion (14a) installed on a rear surface side of the chute (<NUM>) and configured to emit light to the object to be sorted through an opening, a light receiving part (<NUM>) configured to receive at least one of transmitted light and reflected light from the object to be sorted of the light emitted from the illuminating part (<NUM>), and an optical path configured to send at least one of the transmitted light and the reflected light to the light receiving part, the optical inspection unit (<NUM>) being configured to inspect the object to be sorted flowing down on the front surface of the chute (<NUM>); and
an ejector unit (<NUM>) having an ejector nozzle (<NUM>) capable of ejecting air to the object to be sorted flowing down on the front surface of the chute (<NUM>), and configured to sort and remove the object to be sorted based on an inspection result obtained by the optical inspection unit (<NUM>),
the optical sorting device (<NUM>) characterized by comprising:
a base member attached to the rear surface side of the chute (<NUM>), wherein
at least the rear-side illuminating portion (14a) and the ejector nozzle (<NUM>) are attached to the base member, and the base member is installed such that the opening of the rear-side illuminating portion faces the optical detection slit (<NUM>), and a leading end of the ejector nozzle faces the sorting and removal slit (<NUM>), and
wherein the base member or the rear-side illuminating portion (14a) includes a positioning protrusion to be inserted into the optical detection slit (<NUM>) to position the base member on the chute (<NUM>).