JP6142119B2 - Powder sterilizer - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a granular material sterilization apparatus that sterilizes a granular material such as foods, food additives, and pharmaceuticals by irradiating ultraviolet rays or the like.

  Conventionally, as a method for sterilizing bacteria, mold, yeast, etc., a method using a gas such as ethylene oxide and ozone, a method using radiation, a method using heating, and a method using ultraviolet rays are known. An appropriate sterilization method has been selected and adopted in accordance with the properties and the required degree of sterilization.

  When sterilizing food, food additives, etc., it is necessary to pay particular attention to the selection of the sterilization method. For example, even if you try to sterilize food using ethylene oxide or ozone gas or radiation, the use of gas or radiation is prohibited from the viewpoint of safety, or there are certain restrictions on the use There is. When sterilizing by heating, proteins constituting powdered foods may be denatured, and when sterilizing by moist heat, the object to be sterilized may absorb moisture and denature. There is. Furthermore, sterilization by heating may have an insufficient sterilizing effect on heat-resistant bacteria (spore bacteria, etc.).

  On the other hand, sterilization with ultraviolet rays does not have the above-mentioned problems, but there is a problem that it is not easy to sterilize a large amount of powder particles uniformly. Even if the particles loaded on a tray or the like are irradiated with ultraviolet rays, only the surface layer is irradiated with ultraviolet rays, so only the surface layer can be sterilized. This is because it cannot be done. Therefore, sterilization with ultraviolet rays has been used only for surface sterilization applications such as water sterilization, air sterilization, and food packaging materials.

  In recent years, various methods have been proposed for solving the problems in sterilizing the above-mentioned powder particles by ultraviolet light and efficiently sterilizing a large amount of powder particles. For example, Patent Document 1 describes a powder sterilizer including a rotating drum installed to be inclined in the rotating shaft direction and an ultraviolet lamp provided at the position of the rotating shaft in the rotating drum. . This powder sterilization apparatus continuously puts the powder of the sterilization object from one end on the high side of the rotary drum, and applies ultraviolet light to the sterilization target while mechanically stirring the sterilization target in the rotary drum. It comes to irradiate.

  Patent Document 2 describes a sterilization apparatus including a screw conveyor having spiral blades and a source of sterilizing radiation such as an ultraviolet lamp. The screw conveyor is formed by forming spiral blades inside a pipe portion made of an ultraviolet light transmissive material, and the ultraviolet lamp is disposed outside the pipe portion. In this sterilization apparatus, powder particles of an object to be sterilized are continuously charged to the start end side of the screw conveyor, and the object to be sterilized is irradiated with ultraviolet rays while being stirred with the screw.

  Patent Document 3 discloses a powder and ultraviolet sterilization method including a cylindrical container, a vortex impeller provided at the center inside the bottom, and a plurality of ultraviolet lamps installed in a space above the vortex impeller in the cylindrical container. An apparatus is disclosed. The vortex impeller can generate an air flow (vortex) that flows upward. Then, the powder UV sterilizer puts the powder to be sterilized above the vortex impeller, and irradiates the sterilization object with ultraviolet rays while dispersing the sterilization object in the space by the vortex created by the vortex impeller. And sterilize.

  Further, Patent Document 4 discloses an ultraviolet ray provided with a cylindrical casing, a conveyance tube disposed inside the casing and extending spirally along the axis of the casing, and an ultraviolet lamp that irradiates the ultraviolet ray sterilization lamp on the conveyance tube. A sterilizer is described. The transport tube is made of an ultraviolet light transmissive material so that the ultraviolet light irradiated from the ultraviolet lamp can pass through the tube. The ultraviolet sterilization apparatus is configured to continuously put powder, which is an object to be sterilized, into a conveyance tube, and to irradiate the object to be sterilized with ultraviolet rays while conveying the sterilization object in the conveyance tube by air. Further, in order to prevent the surface of the transfer tube and the powder transferred in the transfer tube from being charged, the transfer tube is grounded.

JP 2005-318816 A JP-A-5-570001 JP 2000-116758 A JP-A-10-127737

  However, since each sterilizer described in Patent Documents 1 and 2 is configured to mechanically agitate the powder particles existing in a bulk shape, in order to sufficiently agitate the powder particles, it is long. It was necessary to carry out the stirring work for a time.

  In addition, when using the powder UV sterilizer described in Patent Document 3, after a certain amount of powder is put into the powder UV sterilizer in a single operation, the charged powder is sterilized. It is necessary to perform a batch operation of collecting the sterilized powder particles and carrying them out of the powder particle UV sterilizer. Therefore, the particulate UV sterilizer of Patent Document 3 has a problem that the particulates cannot be processed continuously and the working efficiency is low. In general, since the sterilization effect by ultraviolet rays is proportional to the inverse of the square of the distance between the sterilization object and the ultraviolet light source, it is preferable to keep the distance between all the sterilization objects and the ultraviolet light source uniform. However, in the granular material ultraviolet sterilizer of Patent Document 3, since the ultraviolet rays are irradiated while the granular material is dispersed in a relatively wide space, the distance between the granular material and the ultraviolet ray source cannot be kept uniform. There was a problem that the powder particles could not be sterilized uniformly. Moreover, in the granular material ultraviolet sterilization apparatus described in patent document 3, the area | region where the density | concentration of a granular material is high is formed in the side wall vicinity of a cylindrical container with the centrifugal force of the vortex | eddy_current generated with a vortex | eddy current impeller. And since the area | region with a high density | concentration is formed in the position farthest from an ultraviolet lamp, the bactericidal effect in an area | region with a high density | concentration will become low. In addition, since a low concentration region is formed between the high concentration region and the ultraviolet lamp, the low concentration region blocks the ultraviolet rays, further reducing the sterilization effect of the high concentration region. . Moreover, the vortex impeller of the granular ultraviolet sterilizer described in Patent Document 3 includes a rotating shaft connected to a motor, and the rotating shaft of the vortex impeller passes through a cylindrical container and is connected to the motor. Yes. In order to ensure the sealing performance of the cylindrical container, it is necessary to provide a mechanical seal or the like at a location where the rotating shaft penetrates. However, if such a sealing structure is provided, powder particles enter the gap of the rotating shaft. However, the frictional heat between the rotating shaft and the seal structure may cause the granular material to be denatured or the parts may be damaged due to friction. Safety problems are likely to occur.

  When the ultraviolet ray sterilizer described in Patent Document 4 is used, when the powder flow passes through the conveying tube, the powder flowing near the tube wall is easily subjected to ultraviolet rays, but the powder flowing in the center is not easily subjected to ultraviolet rays. Therefore, there has been a problem that it is difficult to sterilize the powder evenly and uniformly.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a powder sterilization apparatus capable of sterilizing a large amount of powder particles uniformly and efficiently without unevenness. And

  In order to solve the above-mentioned problems, the present invention provides an introduction port for introducing a granular material, a sterilization treatment space for applying a sterilizing electromagnetic wave to the granular material introduced from the introduction port, and this A sterilization transport pipe having a discharge port for discharging powder sterilized in the sterilization processing space, and the flow through the sterilization processing space from the introduction port to the discharge port, and the granular material from the introduction port to the discharge port An airflow generation device that generates an airflow for transporting the airflow and an airflow adjustment structure that adjusts the direction in which the airflow generated by the airflow generation device flows in the sterilization transport pipe.

  According to this invention comprised in this way, the direction of the airflow which flows through the inside of the sterilization process space extended in the axial direction of the transport pipe for sterilization can be adjusted with an airflow adjustment mechanism. And by adjusting the direction of the air flow, it is possible to adjust the transport path of the granular material that is transported on the air flow, thereby adjusting the time to stay in the sterilization treatment space it can. Thereby, it is possible to apply a bactericidal electromagnetic wave over a long time to the powder particles moving in the sterilization treatment space, and the powder particles can be uniformly sterilized. Moreover, according to this invention, it can sterilize in a sterilization processing space, introduce | transducing a granular material into the transport pipe for sterilization from an inlet, and discharging the sterilized granular material from a discharge port. . Thereby, a sterilization process can be performed continuously and a sterilization process can be performed efficiently.

  In the present invention, preferably, the sterilization transport pipe has a granular material flowing in the sterilization treatment space and a charge suppression structure for suppressing charging of the sterilization transport pipe.

  According to the present invention configured as described above, it is possible to suppress the charging of the granular material flowing in the sterilization treatment space and the sterilization transport pipe by the antistatic structure, and thereby the dust in the sterilization treatment space. An explosion can be prevented. In this case, the charge suppression structure preferably suppresses the charge amount on the surface of the sterilization transport tube to 4 kV or less. In this case, the charge suppression structure includes a conductor that is provided inside the sterilization transport pipe and is grounded to the ground potential.

  In the present invention, preferably, the air flow adjusting structure is configured so that the air flow generated by the air flow generating device flows in a tangential direction of the inner peripheral surface of the sterilization transport pipe after passing through the introduction port. Adjust the direction.

  According to the present invention configured as described above, the air flow can flow along the inner peripheral surface of the sterilization transport tube after the air flow flows into the sterilization transport tube from the introduction port. Thereby, an air flow can be made to flow in the direction of a discharge port, spirally turning in the sterilization processing space along the inner peripheral surface of the sterilization transport pipe.

  In the present invention, preferably, the airflow adjustment structure is an adjustment member that is disposed in the sterilization treatment space and provided with a spiral groove extending from the inlet side toward the outlet side.

  In this case, the groove of the adjustment member decelerates the axial velocity of the air flow more than when entering the groove of the adjustment member, and the direction of the air flow coming out of the groove along the inner peripheral surface of the sterilization transport pipe The shape is determined so that it flows.

  According to the present invention configured as described above, the adjustment member disposed in the processing space for sterilization reduces the axial velocity of the airflow more than when entering the groove of the adjustment member, and transport for sterilization. The direction can be directed along the inner peripheral surface of the tube. Then, by reducing the axial velocity of the air flow using the adjusting member and releasing it from the groove of the adjusting member into the sterilization treatment space, the space between the spirals of the air flow is made narrower than when flowing into the groove of the adjusting member. be able to. And by making the air flow into a spiral with a narrow interval, the time for the air flow to stay in the sterilization treatment space can be lengthened. Thereby, the time which the granular material on the airflow stays in the sterilization processing space can be lengthened, and the sterilization processing efficiency of the granular material can be increased.

  In the present invention, preferably, a bar member extending in the axial direction of the sterilization transport pipe is disposed in the sterilization transport pipe, and the outer peripheral surface of the bar member is mirror-finished.

  According to the present invention thus configured, the bactericidal electromagnetic wave irradiated from the outside of the sterilization transport pipe can be selectively reflected in the radial direction of the bar member without being irregularly reflected by the outer peripheral surface of the bar member. it can. Thereby, a granular material can be sterilized more efficiently.

  In the present invention, preferably, at least the outer surface of the bar member is formed of a conductor, and the conductor is grounded to a ground potential.

  According to the present invention configured as described above, the rod member can suppress the charging of the granular material flowing in the sterilization treatment space and the transport pipe for sterilization, and thereby the dust explosion in the sterilization treatment space. Can be prevented from occurring.

  In the present invention, the bactericidal electromagnetic wave is preferably ultraviolet rays.

  As described above, according to the present invention, a large amount of powder particles can be sterilized uniformly and efficiently without unevenness.

It is a front view which shows the granular material sterilizer by embodiment of this invention. It is a top view which shows the sterilization process part by embodiment of this invention. It is sectional drawing of the III-III cross section of FIG. It is sectional drawing of the IV-IV cross section of FIG. It is sectional drawing which shows the internal structure of the transport pipe for sterilization by embodiment of this invention. It is a trihedral view showing an adjustment member according to an embodiment of the present invention. It is a graph which shows the displacement of the granular material flow which flows through the groove | channel of the adjustment member by embodiment of this invention, speed, and acceleration. It is sectional drawing which shows the modification of the internal structure of the transport pipe for sterilization by embodiment of this invention. It is sectional drawing which shows the further modification of the internal structure of the transport pipe for sterilization by embodiment of this invention.

  Hereinafter, with reference to drawings, a granular material sterilizer by an embodiment of the present invention is explained.

  FIG. 1 is a front view showing a powder sterilizer according to an embodiment of the present invention. As shown in FIG. 1, the granular material sterilization apparatus 1 includes a granular material supply unit 3 for supplying a granular material W to be sterilized and a granular material W supplied from the granular material supply unit 3. The sterilization processing unit 5 for sterilizing the powder, the granular material recovery unit 7 for recovering the sterilized granular material W, the granular material supply unit 3, the sterilization processing unit 5 and the granular material recovery unit 7 An airflow generation unit 9 that generates an airflow for conveying the body W is provided, and each unit is connected in this order via a predetermined transport pipe.

  The granular material supply unit 3 quantitatively supplies the main hopper 11 into which the granular material W to be sterilized and the granular material W accommodated in the main hopper 11 are supplied to the auxiliary hopper 13 quantitatively. Device 15. A sterilization HEPA filter (High Efficiency Particulate Air Filter) 17 is attached to the auxiliary hopper 13, and air is introduced into the auxiliary hopper 13 through the HEPA filter 17 by the suction force generated by the airflow generation unit 9. Is configured to capture. In addition, an electromagnetic vibrator (not shown) for preventing clogging of the granular material W is provided in the auxiliary hopper 13. And the granular material W carried into the auxiliary hopper 13 from the main hopper 11 is carried into the sterilization processing unit 5 through the carrying-in transport pipe 19 extending between the granular material supply unit 3 and the sterilization processing unit 5. . The granular material W that has entered the carry-in transport pipe 19 rides on the air flow generated by the suction force from the airflow generation unit 9 and diffuses in the carry-in transport pipe 19 to be sterilized as a granular material flow W1. Flows to 5.

  The carrying-in transport pipe 19 is a pipe body that connects the auxiliary hopper 13 and the sterilization processing unit 5, and a HEPA filter 21 is attached to one end thereof. The carry-in transport pipe 19 takes in outside air via the HEPA filter 21 on the upstream side of the auxiliary hopper 13 by the suction force of the airflow generation unit 9 and flows it toward the downstream side.

  A sterilizing filter that can be detached is installed near the entrance of the main hopper 11 to prevent germs from entering the main hopper 11. By installing a filter in the vicinity of the inlet of the main hopper 11, it is possible to more effectively prevent foreign matters and bacteria from being mixed, whether air is sucked or discharged.

  The type of gas used to carry the powder W is not limited to air, and can be selected as appropriate. For example, as a gas used for transporting the granular material W, nitrogen, argon, or the like can be used in addition to easily usable air.

  The granular material W in this embodiment contains powder and a granular material. Here, the powder is an aggregate of particles having a longest diameter of 1 mm or less, and the form is not limited. In addition, the granular material includes forms such as a granular shape, a pellet shape, a chip shape, a fiber shape, and a flake shape, and the size is not particularly limited, and can be conveyed in the carrying-in transport pipe 19. Anything is acceptable.

  Moreover, the kind and composition of the granular material W are not specifically limited. Examples of the powder W include powdered food such as wheat flour, rice flour, soybean flour, starch, coffee powder / granules, powdered dairy products, dried vegetables, dried seaweed, dried fruits, freeze-dried foods, etc. Obtained granular health foods; solid seasonings such as salt, sugar, umami seasonings, spices; guar gum, carrageenan, pectin, locust bean gum, gum arabic, xanthan gum, tara gum, karaya gum, agar, glucomannan, tamarind seed gum And food additives such as psyllium seed gum; powdered pharmaceuticals; powdered quasi-drugs; seeds such as rice, wheat, soybeans, vegetables and pepper.

  2 is a plan view showing a sterilization section according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2, and FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. As shown in FIGS. 2 to 4, the sterilization processing unit 5 includes a sterilization transport pipe 23 through which the granular material flow W <b> 1 sent from the carry-in transport pipe 19 passes, and a sterilization transport pipe from the outside of the sterilization transport pipe 23. A plurality of ultraviolet irradiation lamps 25 for irradiating ultraviolet rays toward the tube 23 are provided. The sterilization transport pipe 23 is formed of a linearly extending tubular body having one end connected to the carry-in transport pipe 19 and the other end connected to the carry-out transport pipe 27. The sterilization transport pipe 23 has a circular cross section having substantially the same diameter from one end to the other end. Further, the sterilization transport pipe 23 is provided with an introduction port 29 for receiving the granular material flow W1 on one end side, and a discharge port 31 for discharging the granular material flow W1 on the other end side. The discharge port 31 of the sterilization transport pipe 23 is connected to the granular material collection unit 7 via the carry-out transport pipe 27. The sterilization transport tube 23 is formed of a material that transmits ultraviolet rays irradiated from the ultraviolet irradiation lamp 25. Examples of the sterilization transport tube 23 include a quartz glass tube, an ultraviolet transmissive fluororesin tube, and Teflon (registered trademark). ) A pipe etc. can be used. Further, when a quartz glass tube is adopted as the sterilization transport tube 23, it is preferable to use a quartz glass tube having an ultraviolet transmittance of 70% or more. Alternatively, the sterilization transport pipe 23 may be formed of a conductor and grounded to a ground potential. Thereby, electrification of granular material W and sterilization transport pipe 23 can be controlled. The capacity and thickness inside the sterilization transport pipe 23 can be appropriately selected according to the scale of the powder sterilizer 1. In particular, the thickness of the sterilization transport pipe 23 needs to be set so as to ensure mechanical strength against negative pressure by suction or pressurization by discharged gas.

  Further, the sterilization transport pipe 23 extends in a substantially vertical direction, and a carrying transport pipe 19 extending in a substantially horizontal direction is connected to one end (lower end) thereof. Thereby, the granular material flow W <b> 1 carried in from the carry-in transport pipe 19 is carried into the sterilization transport pipe 23 from one end of the sterilization transport pipe 23. The carry-in transport pipe 19 is connected to the sterilization transport pipe 23 so as to extend in the tangential direction of the horizontal cross section of the sterilization transport pipe 23. The carry-in transport pipe 19 and the sterilization transport pipe 23 are When the connecting portion is viewed from above (FIG. 4), the inner wall of the carrying transport pipe 19 is connected to the inner peripheral surface of the sterilizing transport pipe 23 so as to be smoothly continuous. The direction of the granular material flow W <b> 1 is adjusted to the tangential direction of the inner peripheral surface of the sterilization transport pipe 23 after the air flow enters the inlet 29 by the carry-in transport pipe 19 and the sterilization transport pipe 23. Thereby, when the granular material flow W1 flows from the carrying-in transport pipe 19 into the sterilization transport pipe 23, the granular material flow W1 including a large amount of the granular material W is a horizontal cross section of the sterilization transport pipe. Flows tangentially. And the granular material flow W1 is along the inner peripheral surface of the transport pipe 19 for sterilization by the resultant force of the suction input from the discharge port 31 side of the transport pipe 23 for sterilization and the propulsive force in the tangential direction of the horizontal section. Ascend while spirally turning.

A plurality of ultraviolet irradiation lamps 25 are arranged around the sterilization transport tube 23. The plurality of ultraviolet irradiation lamps 25 are, for example, straight tube lamps extending in parallel with the sterilization transport tube 23, and around the sterilization transport tube 23 so as to form a concentric ring with the sterilization transport tube 23. They are arranged at equal intervals. As the ultraviolet irradiation lamp 25, a general low-pressure mercury sterilization lamp, a medium-pressure mercury sterilization lamp, or the like can be used. The shape and number of the ultraviolet irradiation lamps 25 are appropriately selected according to the scale of the powder sterilizer 1 so that the powder W can be sufficiently sterilized. Moreover, the intensity | strength which irradiates an ultraviolet-ray can also be suitably selected according to the scale of the granular material sterilizer 1, the kind and quantity, etc. of the granular material W used as the sterilization processing object.

  Further, the sterilization transport pipe 23 has a rod member 33 disposed concentrically with the sterilization transport pipe 23 therein.

  FIG. 5 is a cross-sectional view showing the internal structure of the sterilization transport pipe.

  As shown in FIG. 5, the bar member 33 has substantially the same length as the sterilization transport pipe 23 and is disposed inside the sterilization transport pipe 23 so as to extend over the entire length of the sterilization transport pipe 23. Yes. The rod member 33 is a cylindrical member or a columnar member having a diameter smaller than the inner diameter of the sterilization transport pipe 23, and is held by the support member 35 at a position away from the inner peripheral surface of the sterilization transport pipe 23. Yes. Then, by disposing the bar member 33 inside the sterilization transport pipe 23, a cylindrical sterilization treatment space 37 is formed between the inner peripheral surface of the sterilization transport pipe 23 and the outer peripheral surface of the bar member 33. Yes. The rod member 33 is preferably formed of a conductor such as metal, and is preferably grounded to the ground potential through the support member 35, for example. Thereby, electrification of granular material W and transportation pipe 23 for sterilization can be controlled. Moreover, it is preferable that the outer peripheral surface of the rod member 33 is mirror-finished. Thereby, the ultraviolet rays irradiated from the ultraviolet irradiation lamp 25 can be selectively reflected in the radial direction of the bar member 33 without irregular reflection, and the powder W can be sterilized more efficiently.

  Moreover, the rod member 33 may be formed from one member, and may be formed by connecting several members. The adjustment member 39 for adjusting the direction of the airflow in the cylindrical sterilization treatment space 37 in the sterilization transport pipe 23 may be installed in one or a plurality of locations of one bar member. In the present embodiment, the rod member 33 is formed by connecting three cylindrical members or columnar members 33a, 33b, and 33c. And the connection part of each cylindrical member or columnar member 33a, 33b, 33c is connected by the adjustment member 39 for adjusting the direction of the airflow in the cylindrical sterilization processing space 37 in the sterilization transport pipe 23. Yes.

  FIG. 6 is a trihedral view showing the adjustment member. The adjustment member 39 narrows the width of the spiral by adjusting the direction of the spiral air flow generated when the particulate flow W1 flows into the sterilization transport pipe 23 from the carry-in transport pipe 19 and thereby the sterilization flow. Increase the residence time of the airflow in the transport pipe. The adjustment member 39 is formed by cutting a spiral groove 41 having a predetermined shape on the outer peripheral surface of a cylindrical body having an outer diameter substantially the same as the inner diameter of the sterilization transport pipe 23. The adjustment member 39 is formed of a conductor such as metal, and the adjustment member 39 is fixed to the end of the cylindrical member or the columnar members 33a, 33b, and 33c constituting the rod member 33 using, for example, screws. Thus, the adjacent cylindrical members or columnar members 33a, 33b, 33c are integrally held. Thereby, also with the adjustment member 39, charging of the granular material W and the transport pipe 23 for sterilization can be suppressed. And by arrange | positioning the adjustment member 39 in the transport pipe 23 for sterilization, the cylindrical sterilization processing space 37 in the transport pipe 23 for sterilization is substantially divided by the adjustment member 39, and the divided spaces are separated from each other. These are connected only by the groove 41 formed in the adjusting member 39.

  Next, the shape of the groove 41 of the adjustment member 39 will be described in detail.

  The groove 41 has one spiral shape that goes around the circumference of the columnar adjustment member 39 along the outer periphery of the adjustment member 39. The groove 41 is shaped so as to reduce the interval between the spiral airflows by increasing the axial velocity of the airflow and to increase the number of turns in the sterilization treatment space 37. The groove 41 is shaped so that the axial velocity and axial acceleration of the airflow are once increased and then decreased in the groove 41, so that the granular material W stays and accumulates in the groove 41. Can be prevented. Specifically, the adjustment member 39 includes an inlet 41a formed on the bottom surface and an outlet 41b formed on the top surface, and the airflow rising while spirally turning in the sterilization treatment space 37 is generated. , And flows from the inlet 41a of the groove 41. The inlet 41a is a substantially annular opening formed on the bottom surface of the adjusting member 39. As shown in FIG. 6, the inlet 41a has an angle around the axis of the adjusting member 39 starting from the inlet 41a of the groove 41 of the adjusting member 39. Open except for around 0 degrees. Therefore, the inlet 41a has substantially the same size as the horizontal cross section of the sterilization treatment space 37, and can receive a large amount of airflow. On the other hand, the outlet 41b of the groove 41 is a semi-annular opening formed on the top surface of the adjustment member 39, and opens from 180 degrees (540 degrees) to 360 degrees (720 degrees) as shown in FIG. ing. Accordingly, the area of the outlet 41b is smaller than that of the inlet 41a. The groove 41 is sharply narrowed immediately after entering the groove from the inlet 41a (360 degrees to 450 degrees), and extends in a substantially horizontal direction for a while (up to about 540 degrees). As a result, the airflow flowing into the groove 41 is decelerated in the vertical direction so that the vertical velocity is substantially zero and is accelerated in the horizontal direction. In the vicinity of the outlet 41b (after 540 degrees), the bottom surface of the groove 41 is inclined upward, thereby slightly accelerating the airflow in the vertical direction. The vertical speed at this time is slower than when the airflow flows into the groove 41. As a result, the air flow released from the groove 41 into the sterilization space 37 rises in the sterilization space 37 while turning in a spiral with a narrower interval than when flowing into the adjustment member 39.

  Returning to FIG. 1, the granular material recovery unit 7 includes a main recovery unit 45 having a main storage unit 43 and an auxiliary recovery unit 49 having an auxiliary storage unit 47. The main recovery unit 45 separates the granular material flow W1 sent from the sterilization transport pipe 23 into the granular material W and air, collects the granular material W in the main storage unit 43, and supplies the air to the subsequent stage. Send to collection unit 49. Most of the granular material W contained in the granular material flow W1 is recovered in the main accommodating portion 43, but some fine granular materials W cannot be recovered and remain in the air. The fine granular material W is separated using the auxiliary recovery unit 49 and stored in the auxiliary storage unit 47. In addition, the air flow generation unit 9 is connected to the downstream side of the auxiliary recovery unit 49.

  The airflow generation unit 9 is configured by a blower that sucks air, and generates an airflow that flows from the upstream side toward the downstream side in the granular material supply unit 3, the sterilization processing unit 5, and the granular material recovery unit 7. Let Then, the air flow generation unit 9 discharges the air in the auxiliary recovery unit 49 located on the most downstream side of the granular material recovery unit 7 through the dust collection air filter 51 to the outside.

  In the present embodiment, a blower is illustrated as the airflow generation unit 9. However, according to the present invention, the granular material W may be transported by providing a blower on the most downstream side of the transport path and sucking air. Then, a device for discharging air may be provided in the uppermost stream of the transport path, and the granular material W may be transported by sending air or the like.

  Next, the operation of the powder sterilizer 1 will be described in detail.

  When the granular material W is thrown into the granular material supply unit 3, the granular material flow W <b> 1 in which the granular material W is diffused in the air by the suction force of the airflow generation device 9 passes through the carrying transport pipe 19. It is sent to the introduction port 29 of the sterilization transport pipe 23. Since the carrying-in transport pipe 19 is connected to the sterilizing transport pipe 23 so as to extend in the tangential direction of the horizontal cross section of the sterilizing transport pipe 23, the sterilizing transport pipe 23 is connected to the introduction port 29 of the sterilizing transport pipe 23. The granular material flow W <b> 1 that has flowed into the interior flows spirally in the cylindrical sterilization treatment space 37 while flowing in the direction of the discharge port 31 and reaches the upstream side of the adjustment member 39. Next, an effect | action when the granular material flow W1 flows through the inside of the adjustment member 39 is explained in full detail.

  FIG. 7 is a graph showing the displacement, velocity, and acceleration of the granular material flow W1 flowing through the groove of the adjustment member. In the graph, the displacement s indicates the axial displacement of the granular material flow W1 in the adjusting member, the velocity v indicates the axial velocity of the granular material flow W1, and the acceleration a indicates the granular material. The axial acceleration of the flow W1 is shown, and the angle θ indicates the angle around the axis of the adjustment member starting from the inlet of the spiral flow path of the adjustment member.

  As shown in FIG. 7, when the granular material flow W1 flowing through the adjusting member 39 enters the groove 41 (angle θ = 0 degree), it flows in a substantially horizontal direction, and the axial velocity v of the granular material flow W1. And the acceleration a is almost zero. Thereafter, the velocity v continues to increase gently until the granular material flow W1 makes more than a half circumference around the adjustment member 39 (angle θ = 225 degrees). The acceleration a continuously and smoothly increases from zero to a maximum value and then changes again to zero. Thereafter, the velocity v continues to decrease until the velocity v becomes substantially zero after the circumference of the adjustment member 39 makes one or more rounds around the adjustment member 39 (angle θ = 450 degrees). During this time, the acceleration a continuously and smoothly increases from zero to the maximum value and then changes again to zero. Thereby, the stay and accumulation of the granular material W in the groove 41 can be prevented. Thereafter, the granular material flow W1 flows in the adjusting member 39 by a quarter of a round (angle θ = 540 degrees) with the axial velocity v being substantially zero. Thereafter, the acceleration a and the speed v continue to increase slightly until the granular material flow W1 exits the groove 41, and flows out from the outlet of the adjustment member 39 into the cylindrical sterilization treatment space 37. As described above, the adjustment member 39 can reduce the axial velocity of the airflow, reduce the interval between the spiral airflows, and increase the number of turns in the sterilization treatment space 37.

  And the granular material flow W1 discharged | emitted to the cylindrical sterilization space 37 receives the ultraviolet-ray irradiated from the ultraviolet irradiation lamp 25, and is sterilized. At this time, the granular material flow W1 becomes an ideal spiral flow by passing through the adjusting member 39, and the granular material W moving in the sterilization treatment space 37 is diffused well in the air without unevenness. The individual powder particles W are likely to be irradiated with ultraviolet rays. Further, the sterilization treatment space 37 has a cylindrical shape due to the presence of the bar member 33, the thickness of the granular material flow W1 is thin and substantially uniform with respect to the ultraviolet irradiation, and the surface of the bar member 33 is exposed to the ultraviolet ray. By being mirror-finished so that it can be reflected, it is possible to irradiate the granular material W with ultraviolet rays in a multifaceted manner, so that the individual granular particles W can receive ultraviolet rays evenly and effectively, and sterilize efficiently. Is done.

  When the granular material flow W1 flowing in the cylindrical sterilization processing space 37 rises in the sterilization processing space 37, the circumferential speed of the granular material flow W1 becomes slow and the interval between the spirals widens. By reaching the member 39 and passing through the adjusting member 39 again, the spiral is again adjusted to an ideal spiral flow. Accordingly, by disposing a plurality of adjusting members 39 at appropriate intervals in the axial direction, the granular material flow W1 becomes an ideal spiral flow at any position in the sterilization transport pipe 23, and the sterilization is efficiently performed. It can be performed.

  The bar member 33 is made of a conductor such as metal and is grounded to the earth potential. Accordingly, it is possible to suppress the charging of the granular material flow W1 flowing inside the sterilization transport pipe 23 and the sterilization transport pipe 23, and to reliably prevent the occurrence of creeping discharge that leads to a dust explosion. .

  And the granular material flow W1 sterilized by passing through the sterilization transport pipe 23 is sent to the subsequent granular material collecting unit 7, and the granular material W as a product is separated and recovered from the granular material flow W1. Is done.

  As described above, in the granular material sterilization apparatus 1 of the present embodiment, the granular material W to be sterilized is input to the granular material supply unit 3, and the sterilized granular material W is the granular material recovery unit. Until it is recovered at 7, the granular material W can be continuously transported and sterilized in the sealed space. Thereby, there is no possibility that the granular material W may be scattered outside the granular material sterilizing apparatus 1 or foreign matter may be mixed in from the outside, and handling of the granular material W is facilitated. Moreover, since there are few drive parts compared with the case where a screw conveyor etc. are used in conveying the granular material W, safety | security can be improved more.

  Further, by connecting the carrying transport pipe 19 and the sterilizing transport pipe 23 in the tangential direction and providing a plurality of adjusting members 39 in the sterilizing transport pipe 23, the granular material flow W1 flowing into the sterilizing transport pipe 23 is provided. It is possible to increase the staying time in the sterilization treatment space 37, thereby irradiating the ultraviolet rays of the ultraviolet irradiation lamps 25 evenly on the individual powder particles W and performing the sterilization treatment more effectively. Can do.

  Further, here, a cylindrical sterilization treatment space 37 is formed by the sterilization transport pipe 23 and the rod member 33, and the granular material flow W1 passes through the cylindrical sterilization treatment space 37. Since the granule moves along the inner wall of the sterilization transport pipe 23 by centrifugal force, the variation in the distance between the individual granule W and the ultraviolet irradiation lamp 25 can be reduced. In addition, since the surface of the bar member 33 is mirror-finished and ultraviolet rays can be selectively reflected in the radial direction of the bar member, the irradiation efficiency of the ultraviolet rays on the granular material W can be improved. Therefore, the granular material W can be sterilized more uniformly and efficiently.

  In addition, a non-conductive quartz glass tube is used as the sterilization transport tube 23, but the powder flow W1 and the sterilization transport tube 23 are charged by a structure in which a metal rod member 33 is grounded to the ground potential. Since it can suppress reliably, the creeping discharge from the glass tube surface can be prevented reliably.

  In addition, the granular material sterilizer 1 of this invention is not limited to the said embodiment. For example, the shape of the groove 41 of the adjusting member 39 may be different from the illustrated shape, and the powder flow W1 that spirals around the central axis of the sterilization transport tube 23 and passes through the inside thereof is axially directed. It only has to be able to decelerate.

  Further, the number of adjusting members 39 may be provided as many as necessary to continue the spiral flow of the granular material flow W1, and may be appropriately increased or decreased depending on the length of the sterilization transport pipe 23 and the like. it can. When the length of the sterilization transport pipe 23 is short, the carrying transport pipe 19 is connected so as to extend in the tangential direction of the horizontal cross section of the sterilization transport pipe 23 so that the granular material flow W1 can flow spirally. If so, the adjustment member 39 may not be used. Further, by forming the adjustment member 39 in the vicinity of the introduction port 29 of the sterilization transport pipe 23, the connection direction of the carry-in transport pipe 19 and the sterilization transport pipe 23 is set in the tangential direction of the horizontal section of the sterilization transport pipe 23. There is no need to do it.

  FIG. 8 is a cross-sectional view showing a modification of the internal structure of the sterilization transport pipe.

  When the sterilization transport pipe 23 is formed of a nonconductor, a strip-shaped conductor 53 is wound around the sterilization transport pipe 23 as shown in FIG. 8, and the conductor 53 is grounded to the ground potential. Also good. In this case, by arranging the conductor 53 in a spiral shape and providing an interval between the respective windings, a gap through which ultraviolet rays pass can be ensured.

  FIG. 9 is a cross-sectional view showing a further modification of the internal structure of the sterilization transport pipe.

  As shown in FIG. 9, by using the ground structure of FIG. 5 and the ground structure of FIG. 8 together, the charge suppression performance can be further improved.

  In any case, the charge suppressing structure for suppressing charging of the particulate flow W1 and the sterilization transport pipe 23 preferably suppresses the charge amount on the surface of the sterilization transport pipe 23 to 4 kV or less. Is 3 kV or less, more preferably 2 kV or less.

  Further, the structure of the granular material supply device and the granular material recovery unit of the present invention is not limited to the above-described configuration, and is a known quantitative supply device depending on the type and properties of the granular material to be sterilized. , Cyclones, etc. can be combined freely.

  Although the ultraviolet-ray generation source used for the granular material sterilization apparatus of this invention is not restrict | limited, Generally a low pressure mercury disinfection lamp and a medium pressure mercury disinfection lamp can be used. In addition to this, an ultraviolet ray source using a weakly ionized low temperature plasma (for example, an apparatus disclosed in WO2009 / 123258), an ultraviolet ray source using a light emitting diode, an external electrode rare gas lamp, or the like can be used as an ultraviolet ray generation source. It is.

  In the above-described embodiment, the structure of the joint portion between the carrying-in transport pipe 19 and the sterilization transport pipe 23 and the adjustment member 39 are given as examples of the airflow adjustment structure. Any structure can be used as long as it can adjust the direction of the airflow in the transport pipe. For example, a structure described in JP-A-08-108935 that adjusts the direction of the airflow from the outside of the pipe is used. It is also possible.

  Next, the contents and results of an experiment (experiment 1 to experiment 7) in which the above-described powder sterilizer is experimentally manufactured and actually sterilized with respect to various powder particles will be described.

First, the materials and dimensions of the main members of the prototyped powder sterilizer will be described. One of the following was adopted as the sterilization transport pipe of the sterilization treatment section.
1) Cylindrical tube made of quartz glass with UV transmittance of 85%, outer diameter of 65mm, inner diameter of 58mm, thickness of 3.5mm 2) Made of UV transparent type fluororesin, inner diameter of 58mm, thickness of 0.4mm Cylindrical tube of cylindrical tube with ultraviolet transmittance (converted calculated value 70%) The cylindrical rod member inside the sterilization transport tube was made of metal and had an outer diameter of 38 mm. A cylindrical space having a thickness of about 10 mm was formed between the sterilization transport tube and the rod member.

As the ultraviolet irradiation lamp, a lamp that emits ultraviolet light centered on a wavelength of about 254 nm was used, and the effective light emission length was about 900 mm. Further, the distance from the outer periphery of the ultraviolet irradiation lamp to the outer peripheral surface of the rod member, that is, the longest distance from the ultraviolet irradiation lamp to the granular material flow W1 was about 20 mm. And since the ultraviolet rays of the three ultraviolet irradiation lamps adjacent to each other are irradiated to the sterilization transport tube and the ultraviolet rays pass through the quartz glass, it is attenuated by about 15%, so the ultraviolet illuminance on the outer peripheral surface of the rod member is About 17 mW / cm ² . However, when the reflected light from the outer peripheral surface of the bar member is considered, it can be seen that the actual ultraviolet illuminance is higher than about 17 mW / cm ² .

  The two adjustment members provided inside the sterilization transport pipe were cylindrical metal materials having a diameter of about 57 mm, and the depth of the groove was about 9.5 mm. Moreover, the ground structure shown in FIG. 9 was adopted as the ground structure that suppresses charging of the granular material flow W1 and the sterilization transport pipe.

  Next, a method for evaluating the number of bacteria remaining in the granular material will be described. The evaluation method for the number of viable bacteria is the number of colonies generated by diluting and dispersing 1 g of granular material in 99 mL of physiological saline, collecting 1 mL, pour it into a standard agar medium, and culturing at 36 ° C. for 48 hours. And the number of colonies was multiplied by 100 to obtain the number of bacteria per gram.

  The following evaluation method was adopted for the number of spore bacteria. First, for the number of heat-resistant bacteria, 1 g of powder granules were diluted and dispersed in 99 mL of physiological saline, 5 mL of this diluted solution was collected, mixed in a standard agar medium, and heated for 10 minutes in a boiling water bath. The number of colonies generated after culturing at 36 ° C. for 48 hours was counted, and the number of colonies was multiplied by 20 to obtain the number of bacteria per 1 g.

  For aerobic thermophilic bacteria, 1 g of powder granules are diluted and dispersed in 99 mL of distilled water, 10 mL of this diluted solution is collected, mixed in dextrose tryptone agar medium, and heated for 20 minutes in a boiling water bath. The number of colonies generated after culturing at 55 ° C. for 48 hours was counted, and the number of colonies was multiplied by 10 to obtain the number of bacteria per 1 g. As for the number of heat-resistant acidophilic bacteria, 2 g of the granular material was diluted and dispersed in 198 mL of physiological saline, adjusted to pH 3.6 to 3.8 using dilute sulfuric acid as the diluted solution, and placed in a 75 ° C. water bath. Heat for 10 minutes. Then, it was mixed with 200 mL of potato dextrose agar medium adjusted to pH 3.6 to 3.8 using dilute sulfuric acid. Then, 20 mL each of this pour solution was put into a sterile petri dish and cultured at 49-51 ° C. for 5 days to count the number of colonies generated. This operation was repeated 5 times, and the total number of colonies generated was added to obtain the number of bacteria per 10 g.

First, Experiments 1 to 5 were performed using a quartz glass tube as a sterilization transport tube.
(1) Experiment 1
A powder additive of food additive (thickening stabilizer) guar gum (manufactured by MRC polysaccharides: RG500, average particle size 82 μm) is put into the powder sterilizer 1 as a 15 kg sterilization target, and the sterilization processing speed is 15 kg / hour. The sterilization treatment was performed under the condition of the exhausted air amount of 0.52 m ³ / min, and the number of general viable bacteria and the number of heat-resistant bacteria before and after the sterilization were evaluated. The evaluation results are shown in Table 1. The charging of the quartz glass surface of the sterilization transport tube 23 was suppressed to a low voltage of 1 kV or less throughout the sterilization time. If a high voltage exceeding 4 kV is generated, creeping discharge leading to a dust explosion may occur, but if it is 1 kV or less, there is no problem.

(2) Experiment 2
Carrageenan (MRC polysaccharides: MV220: average particle size 54 μm) 10 kg of food additive (thickening stabilizer) is charged into the granular sterilizer 1 as a sterilization target, sterilization treatment rate 20 kg / hour, exhausted air volume 0 Sterilization treatment was performed under the condition of .52 m ³ / min, and the number of general viable bacteria and the number of aerobic thermophilic bacteria before and after sterilization were evaluated. The evaluation results are shown in Table 2. The charging of the quartz glass surface of the sterilization transport tube 23 could be suppressed to a low voltage of 1 kV or less throughout the sterilization time.

(3) Experiment 3
15 kg of pectin powder (Danisco pectin: 85 μm) as a food additive (thickening stabilizer) is put into the powder sterilizer 1, the sterilization treatment speed is 15 kg / hour, and the exhausted air volume is 0.52 m ³ / min. The number of heat-resistant acidophilic bacteria before and after sterilization was evaluated. The evaluation results are shown in Table 3. The charging of the quartz glass surface of the sterilization transport tube 23 could be suppressed to a low voltage of 1 kV or less throughout the sterilization time.

  As described above, results of good sterilization rates were obtained in all experiments, and sterilization performance was further improved by optimizing the settings of UV irradiation amount and sterilization transport pipes for each part of the powder sterilizer It is also possible to make it.

(4) Experiment 4
As a food powder, commercially available wheat flour, upper fresh powder, and kinako flour are put into the granule sterilizer 1 as 1 kg sterilization target, and sterilized under conditions of a sterilization rate of 15 kg / hour and a discharge rate of 0.52 m ³ / min. And the number of general viable bacteria before and after sterilization was evaluated. The evaluation results are shown in Table 4. The maximum charge on the quartz glass surface of the sterilization transport tube 23 was suppressed to a low voltage of 2.0 kV of wheat flour, 1.5 kV of fresh powder, and 1.3 kV of flour. If a high voltage exceeding 4 kV is generated, creeping discharge leading to a dust explosion may occur, but if it is 2 kV or less, there is no problem.

(5) Experiment 5
As food granules and flakes, put 1kg of commercially available non-washed rice / green tea as sterilization target into the powder sterilizer 1, and sterilize under conditions of sterilization speed of 15kg / hour and exhaust air volume of 0.52m ³ / min. And the number of general viable bacteria before and after sterilization was evaluated. The evaluation results are shown in Table 4. The maximum charge on the quartz glass surface of the sterilization transport tube 23 is not washed rice, but because of green tea 0.5 kV granules and flakes, there is no risk of a dust explosion even if creeping discharge occurs. , Suppressed to a low voltage.

  Next, Experiments 6 to 7 were performed by changing the quartz glass tube to a fluororesin (wall thickness: 0.4 mm) tube as a sterilization transport tube.

(6) Experiment 6
Carrageenan (MRC polysaccharides: MV220: average particle size 52 μm) 10 kg of food additive (thickening stabilizer) is charged into the granular sterilizer 1 as a sterilization target, sterilization treatment rate 15 kg / hour, exhausted air volume 0 Sterilization treatment was performed under the condition of .57 m ³ / min, and the number of viable bacteria and the number of heat-resistant bacteria before and after sterilization were evaluated. The evaluation results are shown in Table 6. The charging of the fluororesin surface of the sterilization transport tube 23 could be suppressed to a low voltage of 0.6 to 2 kV throughout the sterilization time.

(7) Experiment 7
1 kg of commercially available wheat flour as food powder is put into the granular sterilizer 1 as an object to be sterilized, sterilized under the conditions of a sterilization rate of 15 kg / hour and an exhaust air volume of 0.60 m ³ / minute, and live bacteria before and after sterilization A number evaluation was performed. Table 7 shows the evaluation results. The charging of the fluororesin surface of the sterilization transport tube 23 could be suppressed to a low voltage of 0.2 to 1.2 kV throughout the sterilization time.

DESCRIPTION OF SYMBOLS 1 Powder body sterilizer 3 Powder body supply part 5 Sterilization process part 7 Powder body collection part 9 Airflow generation part 19 Carrying transport pipe 23 Sterilization transport pipe 25 Ultraviolet irradiation lamp 29 Inlet 31 Outlet 33 Bar member 37 Sterilization space 39 Adjusting member 41 Groove

Claims (12)

Inlet for introducing the granular material, sterilizing treatment space for sterilizing the granular material introduced from the introducing port by applying bactericidal electromagnetic waves, and the granular material sterilized in this sterilizing treatment space A sterilization transport pipe having a discharge port for discharging
An airflow generator for generating an airflow for flowing in the sterilization treatment space from the inlet to the outlet and transporting the granular material from the inlet to the outlet;
An airflow adjusting structure that is arranged in the sterilization treatment space and adjusts the airflow generated by the airflow generator into a spiral flow in the sterilization transport pipe,
The granular material sterilizer characterized by the above-mentioned . A plurality of the airflow adjustment structures are arranged in the sterilization transport pipe,
The granular material sterilizer according to claim 1 . A rod member extending in the axial direction of the sterilization transport pipe is disposed in the sterilization transport pipe.
The granular material sterilizer according to any one of claims 1 and 2 . The sterilization transport pipe has a powder body flowing in the sterilization treatment space, and a charge suppression structure for suppressing charging of the sterilization transport pipe.
The granular material sterilizer according to any one of claims 1 to 3 . The charge suppression structure suppresses the charge amount on the surface of the sterilization transport tube to 4 kV or less.
The granular material sterilizer according to claim 4 . The charge suppression structure includes a conductor provided inside the sterilization transport pipe and grounded to a ground potential.
The granular material sterilizer according to claim 4 or 5 . The airflow adjustment structure adjusts the direction of the airflow so that the airflow generated by the airflow generation device flows in the tangential direction of the inner peripheral surface of the sterilization transport pipe after passing through the inlet.
The granular material sterilizer according to any one of claims 1 to 6 . The airflow adjustment structure is an adjustment member provided in the sterilization treatment space and provided with a spiral groove extending from the introduction port side toward the discharge port side.
The granular material sterilizer according to any one of claims 1 to 7 . The groove of the adjustment member decelerates the axial velocity of the air flow more than when entering the groove of the adjustment member, and the air flow coming out of the groove flows in a direction along the inner peripheral surface of the sterilization transport pipe. Is shaped like so,
The granular material sterilizer according to claim 8 . The outer peripheral surface of the bar member is mirror-finished,
The granular material sterilizer according to any one of claims 3 to 9 . At least the outer surface of the bar member is formed of a conductor, and the conductor is grounded to a ground potential.
The granular material sterilizer according to any one of claims 3 to 10 . The bactericidal electromagnetic wave is ultraviolet light,
The granular material sterilizer according to any one of claims 1 to 11 .

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