Steam treatment method and steam treatment device

Abstract

To provide a steam treatment method and steam treatment device capable of efficiently performing a steam treatment on harvests stored in multi-stage and multi-row containers carried into a treatment chamber.SOLUTION: A differential pressure sheet 20 that can be attached to the periphery of each container 1 excluding the passage direction of the steam flow is arranged in a manner of being switchable between the attachment posture and the standby posture before attachment in a treatment chamber 11 by using sheet holding means 30. The differential pressure sheet 20 is held in the standby posture, and each container 1 is carried in. Then, the differential pressure sheet 20 in the standby posture is attached to the periphery of each container 1 excluding the passage direction of the steam flow and held in the attachment posture. Next, the treatment chamber 11 is sealed, the steam flow is introduced into the treatment chamber 11 to pass through the interior of each container 1, and the steam treatment is performed on objects stored in each container 1. Then, the treatment chamber 11 is opened, the differential pressure sheet 20 in the attachment posture is switched to the standby posture, and each container 1 after the steam treatment is carried out from the treatment chamber 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vapor heat treatment, and more particularly to a vapor heat treatment method and a vapor heat treatment apparatus suitable for vapor heat treatment in large-scale facilities. [Background technology]

[0002] Vapor heat treatment uses saturated steam and heat to kill citrus fruit flies and melon flies that attach to fruits and vegetables, and to sterilize bacteria that grow on the surfaces of fruits and vegetables. In recent years, the occurrence of sweet potato base rot has been confirmed mainly in Okinawa Prefecture and southern Kyushu, and vapor heat treatment has attracted attention as a countermeasure against this disease.

[0003] The applicant has previously proposed an apparatus for use in vapor heat treatment (Patent Document 1 and Patent Document 2) that utilizes a pressure difference to forcibly create an air flow and pass vapor heat through all gaps between fruits and vegetables using the pressure difference to kill insects and sterilize them, and has also proposed an apparatus for vapor heat treatment using a similar pressure difference that is effective in preventing base rot of sweet potatoes (Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 61-1094 [Patent Document 2] Utility Model Registration No. 3153127 [Patent Document 3] Utility Model Registration No. 3236140 Summary of the Invention [Problem to be solved by the invention]

[0005] The device in Patent Document 1 is a relatively large-scale vapor heat treatment device that uses multiple differential pressure fans to vaporize fruits and vegetables in harvest boxes stacked on multiple pallets all at once, but there is a lot of room for improvement, especially in terms of heat exchange rate.The devices in Patent Documents 2 and 3 are small-scale vapor heat treatment devices that have a high heat exchange rate, but some ingenuity is required for application to large-scale facilities.

[0006] The present invention has been proposed in view of the above-mentioned problems, and has an object to provide a vapor heat treatment method and vapor heat treatment apparatus that are capable of efficiently vapor treating harvested crops stored in multiple tiers and rows of containers brought into a treatment chamber. [Means for solving the problem]

[0007] In order to achieve the above object, the vapor heat treatment method according to the present invention comprises the steps of: A vapor heat treatment method comprising: installing, inside a treatment chamber for performing a vapor heat treatment, multiple rows and rows of breathable containers each containing an object to be vapor heat treated; and passing a steam flow through the inside of each container to vapor heat treat the object contained therein; a differential pressure sheet that can be attached to the periphery of each container except in the direction of passage of the steam flow is disposed inside the treatment chamber and can be switched between an attachment position and a standby position before attachment; The differential pressure sheet is held in a standby position while each container is carried in; Next, a differential pressure sheet in a standby position is attached around each container except in the direction of the steam flow, and is maintained in the attached position; Then, the treatment chamber is sealed, and a steam flow is introduced into the treatment chamber and passed through the interior of each container to vapor-treat the objects contained in each container; Next, the treatment chamber is opened, the differential pressure sheet in the installed position is switched to the standby position, and each container after the vapor heat treatment is removed from the treatment chamber.

[0008] The vapor heat treatment method according to the present invention comprises the steps of: A container installation space is provided inside the treatment chamber in which the vapor heat treatment is performed, leaving an upper space, a front space, and left and right side spaces, in which multiple tiers and rows of containers containing objects to be subjected to the vapor heat treatment are installed; Each container has an open top and is permeable at least in the direction of vapor flow; a differential pressure sheet that can be attached to the periphery of each container except in the direction of passage of the steam flow is disposed inside the treatment chamber and can be switched between an attached posture and a standby posture that is expanded to the upper space and the left and right side spaces; carrying each container into the container installation space while maintaining the differential pressure sheet in a standby position; Next, a differential pressure sheet in a standby position is attached around each container except in the direction of the steam flow, and is maintained in the attached position; Then, the treatment chamber is sealed, and a steam flow is introduced into the treatment chamber and passed through the interior of each container to vapor-treat the objects contained in each container; Next, the treatment chamber is opened, the differential pressure sheet in the installed position is switched to the expanded standby position, and each container after the vapor heat treatment is removed from the treatment chamber. This is the second feature of the method.

[0009] The vapor heat treatment method according to the present invention comprises the steps of: a sheet holding means is provided on the left and right sides inside the treatment chamber, and before each container is carried in, the sheet holding means is used to hold the pressure differential sheet in a standby position in which the sheet is expanded into the upper space and the left and right side spaces; The third feature is that after each container is brought in, the sheet holding means is used to attach a differential pressure sheet in a standby position around each container, except in the direction of steam flow, and maintain the sheet in the attached position.

[0010] The vapor heat treatment method according to the present invention comprises the steps of: A fourth feature is that inside the treatment chamber, the differential pressure sheet is held at at least two points by the left and right sheet holding means in a standby position expanded into the upper space and the left and right side spaces, and is arranged so that in the standby position, it extends left and right through the upper space and hangs down vertically through the left and right side spaces.

[0011] The vapor heat treatment method according to the present invention comprises the steps of: A fifth feature is that weights are attached to the lower ends of the left and right hanging portions of the differential pressure sheet inside the processing chamber.

[0012] The vaporization treatment apparatus according to the present invention comprises: A vapor treatment apparatus comprising: a treatment chamber having multiple rows and multiple tiers of containers each containing an object to be vapor-treated; a steam flow generated by a blower, a heating means, and a humidifying means is supplied to the inside of the treatment chamber and circulated inside the treatment chamber, thereby vapor-treating the object to be vapor-treated contained in each container; a container installation space is provided inside the treatment chamber, leaving an upper space, a front space, and left and right side spaces, in which the multiple tiers of containers containing objects to be subjected to the vapor heat treatment are installed; Each container has an open top and is permeable at least in the direction of vapor flow; a differential pressure sheet that can be attached to the periphery of each container except in the passing direction of the steam flow is disposed inside the treatment chamber and can be switched between an attached posture and a standby posture that is expanded to the upper space and the left and right side spaces; a sheet holding means is installed inside the processing chamber to hold the differential pressure sheet and to switch the differential pressure sheet between the mounting position and the standby position; Using the sheet holding means, the differential pressure sheet is held in a standby position in which it is expanded into the upper space and the left and right side spaces before each container is carried in, and after each container is carried in, the differential pressure sheet in the standby position is attached around each container except in the direction in which the steam flow passes; The main feature of the present invention is that the differential pressure sheet is maintained in the attached position to subject objects contained in each container to vapor heat treatment.

[0013] The vaporization treatment apparatus according to the present invention comprises: A second feature of the sheet holding means is that it comprises an arm support shaft that is supported at a predetermined height on the left and right inner surfaces of the processing chamber and extends in the front-to-rear direction, a pair of front and rear arm members that rotate around the support shaft and hold the differential pressure sheet by switching between an angle in the mounting position and an angle in the standby position, and a sheet support shaft that is supported between the tips of both arm members and supports the differential pressure sheet from below.

[0014] The vaporization treatment apparatus according to the present invention comprises: The third feature of the sheet holding means is that it comprises an arm support shaft supported at a predetermined height on the left and right inner surfaces of the processing chamber and extending in the front-to-rear direction, a pair of front and rear arm members that rotate around the support shaft and switch and hold the differential pressure sheet between an angle in the mounting position and an angle in the standby position, a sheet support shaft that is supported between the tips of both arm members and supports the differential pressure sheet from below, and an angle holding / release mechanism that holds the sheet support shaft at the angle in the mounting position and the angle in the standby position by a rotation operation and releases the held state of the sheet support shaft at the angle in the mounting position and the angle in the standby position when rotated. Effect of the Invention

[0015] As described above, the present invention has the effect of enabling efficient vapor heat treatment of treatment materials contained in containers arranged in multiple tiers and rows within a treatment chamber by using a differential pressure sheet that can be switched between an attached position and a standby position within the treatment chamber. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a cross-sectional view of a treatment chamber of a vaporization treatment apparatus according to an embodiment of the present invention, showing how a pressure differential sheet is attached to a group of containers in the treatment chamber; [Diagram 2] FIG. 2 is a horizontal cross-sectional view of the vaporization treatment apparatus, showing the state in which pressure differential sheets are attached to the container group in the treatment chamber; [Diagram 3] FIG. 2 is a longitudinal sectional view of the vapor heat treatment apparatus, showing a state before a pressure differential sheet is attached to a group of containers in a treatment chamber; [Figure 4] FIG. 2 is a longitudinal sectional view of the vaporization treatment apparatus, showing the state after a pressure differential sheet is attached to a group of containers in the treatment chamber; [Diagram 5] A structural diagram of the main part of the sheet holding means; [Figure 6] FIG. 13 is an explanatory diagram showing the operation of the sheet holding means; [Figure 7] A diagram showing a pallet loaded with containers containing agricultural products, (A) is a front view, (B) is a top view, [Figure 8] FIG. 2 is a cross-sectional view of the treatment chamber, showing the standby position of the pressure differential sheet in the treatment chamber before the container is loaded; [Figure 9] FIG. 2 is a longitudinal sectional view of the treatment chamber, showing the vapor treatment being performed in the treatment chamber; [Figure 10] FIG. 2 is a cross-sectional view of the treatment chamber showing the effect on the pressure differential sheet during the vapor treatment in the treatment chamber; [Figure 11] FIG. 2 is a structural diagram of a main part showing another example of the sheet holding means; [Figure 12] FIG. 13 is an explanatory diagram showing another example of the sheet holding means; [Figure 13] FIG. 13 is a perspective view of a main part showing a ratchet mechanism in the sheet holding means of FIG. 12; [Figure 14] FIG. 14 is a structural diagram showing the ratchet mechanism of FIG. 13; [Figure 15] FIG. 13 is a structural diagram of a main part showing a stopper in the sheet holding means of FIG. 12; [Figure 16] FIG. 15 is an explanatory diagram showing the operation of the ratchet mechanism of FIG. [Figure 17] FIG. 15 is an explanatory diagram showing the operation of the ratchet mechanism of FIG. [Figure 18] 1A and 1B are horizontal and cross-sectional views showing a differential pressure sheet in a standby state in a vapor heat treatment apparatus according to another embodiment of the present invention; [Figure 19] 19A and 19B are diagrams showing a standby state of the differential pressure sheet in the vapor heat treatment device shown in FIG. 18, in which (A) is a horizontal cross-sectional view and (B) is a horizontal cross-sectional view. BEST MODE FOR CARRYING OUT THEINVENTION

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figures 1 to 10 are diagrams showing a vapor treatment apparatus according to an embodiment of the present invention, in which the reference character S indicates a vapor treatment apparatus.

[0018] The vapor heat treatment device S is a device that uses steam and heat to perform a vapor heat treatment on a treatment object such as fruits, horticultural crops, potatoes, etc. In this embodiment, the treatment object is sweet potatoes, and the device is used to sterilize and disinfect root rot bacteria that have infected sweet potatoes.

[0019] As shown in FIGS. 1 to 3, the vaporization treatment apparatus S is provided with an air blowing chamber 12 at the rear of a large treatment chamber 11.

[0020] The processing chamber 11 has a long box shape, and many containers 1 containing sweet potatoes 2 can be arranged in rows front to back and left to right and stacked in multiple stages to process them all at once. The processing chamber 11 has a top panel 11A, left and right side panels 11B, a bottom panel 11C, a front panel 11D, and a back panel 11E. The front panel 11D is provided with an airtight door 19A that seals the opening of the processing chamber 11.

[0021] The blower chamber 12 is a differential pressure chamber that introduces and circulates steam flow inside the treatment chamber 11, and a differential pressure fan (blower) 14 is disposed inside a casing 13. A heater 15 and a humidifier 16 are disposed downstream of the differential pressure fan 14 (in the illustrated example, each is disposed inside the treatment chamber 11).

[0022] The heater 15 is comprised of a hot water coil or an electric heater, and heats the airflow generated by the differential pressure fan 14. The humidifier 16 produces saturated steam from the heated airflow. The humidifier 16 sprays mist-like moisture into the upper space of the treatment chamber 11.

[0023] The blower chamber 12 and the treatment chamber 11 are in communication with each other via an upper communication port 17 and a lower communication port 18. When the differential pressure fan 14 is operated, the steam flow introduced into the treatment chamber 11 passes laterally through the interiors of the multiple rows and columns of containers 1 arranged in the treatment chamber 11, returns to the blower chamber 12 from the lower communication port 18, and circulates into the treatment chamber 11 from the upper communication port 17.

[0024] A container installation space K is provided inside the treatment chamber 11, in which the containers 1 containing the sweet potatoes 2 can be arranged in multiple rows front to back and left to right and stacked up and down in multiple tiers. The container installation space K has an upper space s1 of a predetermined height between it and the ceiling panel 11A, a front space s2 of a predetermined depth between it and the front panel 11D, a rear space s3 of a predetermined depth between it and the back panel 11E, and side spaces s4 of a predetermined width between it and the left and right side panels 11B.

[0025] In this embodiment, the container installation space K can accommodate multiple rows of containers 1 lined up front to back (9 rows in the illustrated example) and multiple rows left to right (4 rows in the illustrated example), as well as being stacked up and down in multiple levels (8 levels in the illustrated example).

[0026] As shown in Fig. 7, the container 1 for storing sweet potatoes 2 is open at the top and has numerous mesh-like ventilation holes 3 on each side and bottom. The container 1 may be a lightweight plastic mesh container used for harvesting sweet potatoes 2, or an agricultural container. The container 1 may be a container with an open top and numerous ventilation holes only on the front and back, or it may be a large container.

[0027] A pressure differential sheet 20 used during the vapor heat treatment is disposed inside the treatment chamber 11. The pressure differential sheet 20 is attached around the numerous containers 1 (hereinafter sometimes referred to as a container group G) installed in the container installation space K of the treatment chamber 11, except in the direction in which the steam flow passes, and utilizes a pressure difference to pass the steam flow from the front to the rear of each container 1, thereby efficiently carrying out the vapor heat treatment.

[0028] The differential pressure sheet 20 is made of a flexible and durable material such as resin, cloth, or canvas, and has a width and depth (length) large enough to cover the entirety of each container 1 installed in multiple rows and tiers in the container installation space K, from above and from the left and right sides, except for the front and rear.

[0029] The differential pressure sheet 20 is capable of being switched between a standby posture (standby position) shown in FIG. 8 and an installation posture (installation position) shown in FIG. 1 and maintained in these postures inside the processing chamber 11 by left and right sheet holding means 30, 30 attached to the inner surface of the processing chamber 11.

[0030] The standby position refers to a position in which the differential pressure sheet 20 is expanded to a height and width that does not interfere with the container installation space K when each container 1 loaded on the pallet 4 is carried into the treatment chamber 11. The mounting position refers to a position in which, after each container 1 loaded on the pallet 4 has all been carried into the treatment chamber 11, the differential pressure sheet 20 is contracted downward and inward from the standby position so that each container 1 can be entirely covered from above and from the left and right sides except for the front and rear.

[0031] The sheet holding means 30 comprises a horizontal shaft 31 that is supported on the inner surface of the left and right side panels 12B of the treatment chamber 11 at a predetermined height (equivalent to the height of the top surface of the topmost container 1) and extends forward and backward, and a pair of front and rear arm members 32, 32 that rotate around the axis of this horizontal shaft 31 and hold the differential pressure sheet 30 in a standby position and an installation position, respectively.

[0032] A sheet support shaft 33 is provided between the tips of the front and rear arm members 32, 32, extending parallel to the horizontal shaft 31 and supporting the differential pressure sheet 30 from below. The horizontal shaft 31 is supported by the inner surface of the side panel 12B via front and rear support parts 34.

[0033] Between the horizontal shaft 31 and the arm members 32, 32, there is interposed a ratchet mechanism 35 which enables the arm member 32 to rotate and to stop and fix the rotation of the arm member 32.

[0034] 5 shows the structure of ratchet mechanism 35. Ratchet mechanism 35 is composed of gear 35A fixed coaxially with horizontal shaft 31 at the base end of arm member 33, claw member 35B rotatably attached to the inner surface of side panel 12B, spring member 35D supported by the tip of support piece 35C attached to side panel 12B, and string member 35E attached to the tip of support piece 35C.

[0035] In the ratchet mechanism 35, the spring member 35D supported on the tip of the support piece 35C biases the tip of the claw member 35B toward the gear 35A, and in the biased state, the claw member 35B meshes with the teeth of the gear 35A. The arm member 32 can be rotated counterclockwise by using the operating rod 36 from the horizontal position (mounted position) to the standing position (standby position) as shown in Fig. 6(A) due to the shape of the teeth of the gear 35A and the interaction of the claw member 35B, and after the rotation, the angle of the standing position is maintained.

[0036] On the other hand, as shown in FIG. 6(B), by pulling down the string member 35E to release the claw member 35B from the meshing position with the toothed wheel 40A, the arm member 32 in the upright position can be rotated clockwise toward the horizontal position.

[0037] Weights 21 extending horizontally in the front-rear direction are attached to both the left and right ends of the differential pressure sheet 20. Due to the left and right weights 21, the differential pressure sheet 20 is maintained in a state in which it is horizontally stretched between the sheet support shafts 33, 33 of the left and right arms 32, 32 at each stage from the standby position to the intermediate position to the installation position, and is also maintained in a state in which it is stretched vertically downward from the sheet support shafts 33, 33.

[0038] A hood 19B is disposed in the rear space s4 of the treatment chamber 11, connecting the rear faces of the last row of each of the containers 1 arranged in multiple rows and tiers to the lower communication port 18. The hood 19B serves to prevent the steam flow passing through the inside of each container 1 from leaking sideways from the rear faces of the last row of each of the containers 1. The differential pressure sheet 20 is disposed so as to partially overlap this hood 19B.

[0039] Fig. 7(A) shows containers 1 containing sweet potatoes 2 arranged in multiple rows and tiers on a pallet 4, and Fig. 7(B) shows a plan view of the numerous containers 1. The pallets 4 are made of lightweight plastic mesh or wood, and have an opening on the front through which the tines of a forklift for transport can be inserted.

[0040] Next, a procedure for subjecting sweet potatoes 2 stored in a container 1 to a vapor heat treatment (sterilization treatment) using the vapor heat treatment apparatus S having the above-mentioned configuration will be described with reference to FIG. 8 etc.

[0041] First, before the container 1 containing sweet potatoes 2 is carried in, the differential pressure sheet 20 is held in an expanded standby position inside the treatment chamber 11, as shown in Fig. 8. When the arm members 32 of the left and right sheet holding means 30 are in a horizontal position, as shown in Fig. 6(A), when the rod-shaped operating stalk 36 is engaged from below with the sheet support shaft 33 at the tip of the arm member 32 and pushed up, the arm member 32 rotates counterclockwise around the horizontal shaft 31 and rises up. This is performed for both the left and right arm members 32.

[0042] When the left and right arm members 32 rise, the differential pressure sheet 20 held by the left and right arm members 32 is lifted upward and expands left and right, and is held in an expanded standby state.

[0043] Next, with the differential pressure sheet 20 in its standby position, a pallet 4 carrying multiple rows and columns of containers 1 containing sweet potatoes 2 is brought into the treatment chamber 11, and the containers 1 containing sweet potatoes 2 are sequentially placed on each pallet 4 from the back to the front of the container installation space K (see Figure 3).

[0044] Once the installation of a predetermined number of containers 1 containing sweet potatoes 2 in the container installation space K has been completed, as shown in FIG. 1, the left and right sheet holding means 30 are operated to switch the differential pressure sheet 20 from the standby position to the installation position.

[0045] To switch the differential pressure sheet 20 to the mounting posture, the string members 35E of the left and right sheet holding means 30 are pulled down. When the left and right string members 35E are pulled down, the claw members 35B are disengaged from the gears 35A, and the arm members 32 in the upright posture rotate so as to fall freely (see FIG. 6(B)). As the left and right arm members 32 rotate, the differential pressure sheet 20 shrinks downward and laterally from the left and right, and is held in the mounting posture (mounting position).

[0046] When switching the differential pressure sheet 20 to the attached position, the operating rod 36 may be used in conjunction with the operation of pulling down the left and right string members 35E. While supporting the sheet support shafts 33 of the left and right arm members 32 with the operating rod 36, the left and right string members 35E are pulled down to release the claw members 35B, and the left and right arm members 32 are gradually tilted until they reach a horizontal position, at which point the string members 35E are released. This causes the differential pressure sheet 20 to come into contact with the top surface of the uppermost container 1, and the left and right arm members 32 are held in a horizontal position.

[0047] Each container 1 installed in the container installation space K is entirely covered from above and from both left and right sides, except for the front and rear, by the differential pressure sheet 20 in the installed position, as shown in Figures 2 and 4. Weights 21 are attached to the left and right lower end portions of the differential pressure sheet 20, and the differential pressure sheet 20 abuts against the top surface of the uppermost container 1 and is stretched left and right, and hangs down along the outer sides of the containers 1 in the outermost left and right rows, stretching up and down.

[0048] Next, the airtight door 19A of the treatment chamber 11 is closed to seal the interior, and the differential pressure fan 14, heater 15, and humidifier 16 are operated in sequence by operating the control device to circulate steam at a predetermined temperature inside the treatment chamber 11. In this embodiment, the humidity inside the treatment chamber 11 is set to 95% or more (97%), and the vapor treatment temperature is set to 48°C.

[0049] During the vapor heat treatment, as shown by the arrows in Figure 9, the steam flow passes from the blower chamber 12 through the upper communication port 17, through the upper space s1 of the treatment chamber 11, downward in the front space s2, passes sideways through the interior of each container 1 from the front surface of each container 1 in the front row, and returns to the blower chamber 12 from the rear surface of each container 1 in the last row through the hood 19B and the lower communication port 18.

[0050] The steam flow that has returned to the blower chamber 12 is raised by the differential pressure fan 14, passes through the upper communication port 17, is heated and humidified by the heater 15 and humidifier 16, and passes again inside each container 1 inside the treatment chamber 11, where the steam treatment is carried out.

[0051] In this manner, the sweet potatoes 2 in each container 1 arranged in the container installation space K within the treatment chamber 11 are subjected to a steam heat treatment, and the root rot fungi that have invaded the sweet potatoes 2 are sterilized.

[0052] The surroundings of the group of containers G arranged in multiple rows and tiers are covered from above and from the left and right sides, except for the front and rear, by a differential pressure sheet 20 in the installed position, so that the steam flow introduced from the front of the front row of container 1 passes through the interior efficiently to the last row of container 1 without escaping to the sides or above, and returns to the inside of the ventilation chamber 12 via the hood 19B.

[0053] This vaporization treatment device S uses a ventilation method called the differential pressure method to create a forced air flow by utilizing differential pressure, so that vaporization heat passes through all the gaps between the sweet potatoes 2 in each container 1, and the vaporization heat acts evenly on all the sweet potatoes 2.

[0054] Due to the pressure difference, as shown in FIG. 10, the pressure difference sheet 20 is in close contact with the upper surface of each container 1 in the top row and also with the side surfaces of each container 1 in the left and rightmost rows. In this respect, too, the steam flow introduced from the front into each container 1 passes through the interiors of all containers 1 efficiently without escaping to the side or upward, allowing the vapor heat treatment to be carried out effectively.

[0055] After the steam heat treatment is completed, post-treatment is performed to lower the core temperature of the sweet potatoes 2, and after the post-treatment is completed, the treatment chamber 11 is opened and the differential pressure sheet 20 is returned to the expanded standby posture (standby position).

[0056] To return the differential pressure sheet 20 to the standby position, as shown in Fig. 6(A), the operating rod 36 is engaged from below with the sheet support shaft 33 of the left and right arm members 32 in a horizontal position, and the operating rod 19 is pushed up to erect the left and right arm members 32. As a result, the differential pressure sheet 20 supported by the left and right arm members 32 is lifted upward and expanded to the left and right, and is maintained in the standby position in an expanded state.

[0057] Once the pressure differential sheet 20 has been returned to its standby position, the container 1 containing the sweet potatoes 2 after the steam treatment inside the treatment chamber 11 is removed together with the pallet 4. Once the steam treatment of the first batch of sweet potatoes has been completed in this manner, the temperature inside the chamber drops, and then the second batch of pallets carrying the containers 1 containing the sweet potatoes 2 before treatment are brought in, the pressure differential sheet 20 is switched to the installed position, the chamber is sealed, and the second and subsequent batches of sweet potatoes are subjected to the steam treatment.

[0058] According to this embodiment, the pressure differential sheet 20 is used to effectively pass steam through the interior of each of the containers 1 in multiple tiers and rows installed in the container installation space K, thereby enabling high-quality vapor heat treatment to be performed. In particular, it is easy to arrange the containers 1 in multiple rows one behind the other, making it possible to handle large-scale vapor heat treatment.

[0059] In addition, the differential pressure sheet 20 can be easily switched between an expanded standby position inside the treatment chamber 11 and a contracted installed position by operating the sheet holding means 30, making it easy to load each container 1 before treatment and unload each container 1 after treatment, and enabling efficient steam treatment of large quantities of sweet potatoes.

[0060] FIG. 11 shows another example of the structure of the sheet holding means.

[0061] The sheet holding means 40 shown in Figure 11 utilizes a gas damper or gas spring, with the end of a gas cylinder 41 rotatably supported midway along the arm member 32, and the end of an extendable rod 42, the piston of which moves within the gas cylinder 41, being rotatably supported by a support part 43 attached to the inner surface of the side panel 11B of the processing chamber 11.

[0062] The sheet holding means 40 shown in Fig. 11 can switch the arm member 32 from a horizontal position to an upright position and from the upright position to a horizontal position by the action of a gas cylinder 41 and an extensible rod 42. The arm member 32 can be rotated by engaging the operating stem 36 with the sheet support shaft 33 and pulling the operating stem 36 up or down.

[0063] The arm member 32 is preferably rotated manually as described above, but may also be rotated forward and backward by a motor or a pneumatic cylinder.

[0064] 12 to 17 show still other examples of the structure of the sheet holding means.

[0065] As shown in FIG. 12, the sheet holding means 60 includes a horizontal shaft 31 that extends forward and backward and is supported at a predetermined height (the same height as the top surface height of the uppermost container 1) via front and rear support parts 61 on the inner surface of the left and right side panels 11B, and a pair of front and rear arm members 32, 32 that rotate around the axis of this horizontal shaft 31 and hold the differential pressure sheet 20 in a standby position (FIG. 12(A)) and an attached position (FIG. 12(B)), respectively, and a sheet support shaft 33 that supports the differential pressure sheet 20 from below is provided between the tips of the front and rear arm members 32, 32.

[0066] A ratchet mechanism 62 is interposed between the horizontal shaft 31 and the arm members 32, 32, which enables the arm member 32 to rotate and to stop and fix the rotation of the arm member 32. The ratchet mechanism 62 is composed of a gear 62A fixed coaxially with the horizontal shaft 31 at the base end of the arm member 32, a pawl member 62B rotatably attached to the inner surface of the support part 61, and a spring member 62C supported by the inner surface of the support part 61.

[0067] 13 and 14, a number of teeth a are protrudingly provided at equal intervals in a certain range around the gear 62A, and an engagement region b is formed where the teeth a engage with the claw member 62B. This engagement region b is formed in a range from an angle exceeding the angle at which the arm member 32 is held in the mounting position of the differential pressure sheet 20 to an angle at which the arm member 32 is held in the standby position of the differential pressure sheet 20. Release regions (free regions) where the engagement between the claw member 61B and the teeth a is released are formed before and after the engagement region b.

[0068] A large number of teeth a are equally spaced and protrude from an area 180 degrees opposite to the meshing area b around the gear 62A. This area is used as a spare meshing area and is not normally used, but if any of the teeth a in the meshing area b is worn or chipped, the gear 62A can be released from the horizontal shaft 31, rotated 180 degrees, and re-fixed, allowing the spare meshing area to be used for meshing with the pawl member 62B.

[0069] 13 and 15, a convex stopper 63 that supports the arm member 32 in a horizontal position is attached to the base end of the arm member 32. When the arm member 32 in an upright position is tilted horizontally around the horizontal axis 31, the stopper 63 comes into contact with and engages with a rubber leg (elastic body) 65 attached to an attachment part 64 supported on the inner surface of the support part 61, thereby maintaining the arm member 32 in a horizontal position.

[0070] FIG. 16(A) shows the state in which the arm member 32 is in a horizontal position. At this time, the claw member 62B is not engaged with the teeth a of the gear 62A and is in a released state (free state). As shown in FIG. 6(A), the arm member 32 can be raised from a horizontal position by pushing up the sheet support shaft 33 from below using the operating rod 36, but as shown in FIG. 16(B), when the arm member 32 rotates upward, the claw member 62B is sequentially engaged with a number of teeth a in the engagement region b of the gear 61A, so that the arm member 32 can be safely and reliably raised. This is performed for both the left and right arm members 32.

[0071] When the left and right arm members 32 are raised to the raised end position (held position at the raised end) shown in Fig. 17(A), the raising operation by the operating rod 36 is stopped. The differential pressure sheet 20 is held by the left and right arm members 32, lifted upward, and expanded left and right, and held in the expanded posture at the raised end position. At this time, the claw member 62B remains engaged with the tooth a (for example, the tooth a located at the end) in the meshing region b of the gear 62A, and the differential pressure sheet 20 is held in the standby posture (standby position) after expansion.

[0072] To switch the pressure differential sheet 20 from the standby position to the installation position (after the installation of a predetermined number of containers 1 containing sweet potatoes 2 in the container installation space K has been completed), the left and right sheet support shafts 33 are pushed up further by the operating rods 36, and the left and right arm members 32 are rotated from the upper end position (Fig. 17(A)) to the upper end over position (Fig. 17(B)). When the arm members 32 are rotated to the upper end over position, as shown in Fig. 17(B), the claw members 62B are disengaged from the meshing region b of the gear 62A, and the meshing between the claw members 62B and the teeth a is released (they become free).

[0073] When the engagement between the claw member 62B and the teeth a is released, the arm member 32 that has been rotated to the over position at the upper end can be freely rotated so as to fall in the opposite direction (clockwise direction in the figure) by using the operating rod 36 or the like. At this time, the claw member 62B maintains a free state without engaging with the teeth a. In this way, the differential pressure sheet 20 contracts downward and laterally from the left and right, and is held in the installation posture (installation position) for the container. In addition, the stoppers 63 of the left and right arm members 32 abut against the rubber legs 65, respectively, and the horizontal posture is maintained.

[0074] As described above, according to the sheet holding means 60 shown in Figures 12 to 17, after a predetermined number of containers 1 have been installed, the arm member 32 can be rotated from the standby posture (standby position) of the differential pressure sheet 20 to the over position at the raised end to release the engagement between the claw member 61B and the teeth a, and the installation operation of the differential pressure sheet 20 can be immediately proceeded to. Also, after the vapor heat treatment, the arm member 32 is rotated to the standby posture position at the raised end to maintain the standby posture, and the operation of unloading and loading can be immediately proceeded to, so that the vapor heat treatment work can be performed more efficiently.

[0075] 18 and 19 show other examples of the structure of the vaporization treatment device.

[0076] The vapor treatment device S' of this embodiment is a small vapor treatment device, and as shown in Figure 18 (A), has a steam flow generator 52 and a treatment chamber 53 on the left and right sides inside a casing 51. Multiple rows and levels of sweet potato-containing containers 1 are placed in the treatment chamber 53, and the steam flow generated by the steam flow generator 52 is introduced into the treatment chamber 53 from below and passes upward through the inside of each container 1, thereby vapor treating the objects inside each container 1.

[0077] 18(A) and 18(B), in the vaporization treatment apparatus S' of this embodiment, a pressure differential sheet 20' having the height of the stacked containers 1 and a length sufficient to cover the periphery of the stacked containers 1 is arranged inside the treatment chamber 53 so as to be U-shaped in plan view along the left and right inner faces from the rear face of the treatment chamber 53. The mating ends of the pressure differential sheet 20' extend parallel to the front so as to make it easy to carry the stacked containers 1 into the treatment chamber 53.

[0078] As shown in Figures 19(A) and (B), the mating ends of the differential pressure sheet 20' are engaged with each other at the front surface of the stacked containers 1, thereby enabling the differential pressure sheet 20' to be maintained in an attached position around the periphery of the stacked containers 1, except for the top and bottom surfaces.

[0079] After the pressure differential sheet 20' is attached, the steam vapor treatment apparatus S' utilizes the pressure difference to circulate steam via the lower communication port 54 and the upper communication port 55, allowing efficient vapor treatment of the sweet potatoes 2 in each container 1. By making the mating ends of the pressure differential sheet 50 detachable, it can be easily opened as shown in Figure 19(B), allowing the inner containers 1 to be smoothly removed and the containers 1 to be untreated to be smoothly brought in, and the pressure differential sheet 20' can be easily attached.

[0080] As described above, according to the present invention, storage containers holding agricultural products are arranged in multiple rows and tiers within a treatment chamber, and steam is circulated to vapor-heat treat the agricultural products, thereby efficiently sterilizing root rot bacteria that have invaded sweet potatoes.

[0081] In addition to sweet potatoes, the objects that can be subjected to the vapor heat treatment in the present invention include fruits, horticultural crops, and tubers. Sweet potatoes can be used for any purpose or variety, such as seed potatoes, raw foods, starch raw materials, and shochu raw materials. The method is suitable for preventing base rot disease in any type of sweet potato. It can be used for insecticidal and quarantine purposes. [Industrial Applicability]

[0082] The present invention can be used as a vapor heat treatment control method in a vapor heat treatment apparatus, and also as a treatment control method for insecticidal or quarantine purposes. [Explanation of symbols]

[0083] 1 Container 2 sweet potato 3. Ventilation holes 4 Palette 11,53 Processing Room 11A Top panel 11B Side Panel 11C Bottom Panel 11D Front panel 11E Back panel 12 Ventilation chamber 14 Differential pressure fan 15,15' heater 16 Humidifier 17,55 Upper communication port 18,54 Lower communication port 19A Door 19B Food 20,20' Differential pressure sheet 21 Weight 30, 40, 60 Sheet retaining means 31 horizontal axis 32 Arm member 33 Seat support shaft 34,43,61 Support part 35,62 Ratchet mechanism (angle retention / release mechanism) 35A,62A Gear 35B,62B Claw member 35C Support piece 35D,62C Spring parts 35E String material 36 Operation culm 41 Gas Cylinder 42 Telescopic Rod 51 Casing 52 Steam flow generator s1 upper space s2 front space s3 rear space s4 Side space S,S' Steaming treatment device

Claims

1. A vapor heat treatment method comprising: installing, inside a treatment chamber for performing a vapor heat treatment, multiple rows and rows of breathable containers each containing an object to be vapor heat treated; and passing a steam flow through the inside of each container to vapor heat treat the object contained therein; a differential pressure sheet that can be attached to the periphery of each container except in the direction of passage of the steam flow is disposed inside the treatment chamber and can be switched between an attachment position and a standby position before attachment; The differential pressure sheet is held in a standby position while each container is carried in; Next, a differential pressure sheet in a standby position is attached around each container except in the direction of the steam flow, and is maintained in the attached position; Then, the treatment chamber is sealed, and a steam flow is introduced into the treatment chamber and passed through the interior of each container to vapor-treat the objects contained in each container; Next, the treatment chamber is opened, the pressure differential sheet in the installed position is switched to the standby position, and each container after the vapor heat treatment is removed from the treatment chamber.

2. A container installation space is provided inside the treatment chamber in which the vapor heat treatment is performed, leaving an upper space, a front space, and left and right side spaces, in which multiple tiers and rows of containers containing objects to be subjected to the vapor heat treatment are installed; Each container has an open top and is permeable at least in the direction of vapor flow; a differential pressure sheet that can be attached to the periphery of each container except in the direction of passage of the steam flow is disposed inside the treatment chamber and can be switched between an attached posture and a standby posture that is expanded to the upper space and the left and right side spaces; carrying each container into the container installation space while maintaining the differential pressure sheet in a standby position; Next, a differential pressure sheet in a standby position is attached around each container except in the direction of the steam flow, and is maintained in the attached position; Then, the treatment chamber is sealed, and a steam flow is introduced into the treatment chamber and passed through the interior of each container to vapor-treat the objects contained in each container; Next, the treatment chamber is opened, the differential pressure sheet in the installed position is switched to the expanded standby position, and each container after the vapor heat treatment is removed from the treatment chamber.

3. a sheet holding means is provided on the left and right sides inside the treatment chamber, and before each container is carried in, the sheet holding means is used to hold the pressure differential sheet in a standby position in which the sheet is expanded into the upper space and the left and right side spaces; 3. The vapor heat treatment method according to claim 2, characterized in that after each container is carried in, the sheet holding means is used to attach a differential pressure sheet in a standby position around each container, except in the direction of passage of the steam flow, and hold the sheet in the attached position.

4. 4. The vapor heat treatment method according to claim 3, wherein inside the treatment chamber, the pressure differential sheet is held at at least two points by the left and right sheet holding means in a standby position in which the pressure differential sheet extends into the upper space and the left and right side spaces, and is arranged so that in the standby position, the pressure differential sheet extends left and right through the upper space and hangs down vertically through the left and right side spaces.

5. 5. The vapor heat treatment method according to claim 4, wherein weights are attached to lower ends of the left and right hanging portions of the pressure difference sheet inside the treatment chamber.

6. A vapor treatment apparatus comprising: a treatment chamber having multiple rows and multiple tiers of containers each containing an object to be vapor-treated; a steam flow generated by a blower, a heating means, and a humidifying means is supplied to the inside of the treatment chamber and circulated inside the treatment chamber, thereby vapor-treating the object to be vapor-treated contained in each container; a container installation space is provided inside the treatment chamber, leaving an upper space, a front space, and left and right side spaces, in which the multiple tiers of containers containing objects to be subjected to the vapor heat treatment are installed; Each container has an open top and is permeable at least in the direction of vapor flow; a differential pressure sheet that can be attached to the periphery of each container except in the passing direction of the steam flow is disposed inside the treatment chamber and can be switched between an attached posture and a standby posture that is expanded to the upper space and the left and right side spaces; a sheet holding means is installed inside the processing chamber to hold the differential pressure sheet and to switch the differential pressure sheet between the mounting position and the standby position; Using the sheet holding means, the differential pressure sheet is held in a standby position in which it is expanded into the upper space and the left and right side spaces before each container is carried in, and after each container is carried in, the differential pressure sheet in the standby position is attached around each container except in the direction in which the steam flow passes; A vapor heat treatment apparatus characterized in that the differential pressure sheet is maintained in the attached position to perform the vapor heat treatment on objects accommodated in each container.

7. 7. The vaporization treatment apparatus according to claim 6, wherein the sheet holding means comprises an arm support shaft supported at a predetermined height on the left and right inner surfaces of the treatment chamber and extending in the front-rear direction, a pair of front and rear arm members that rotate around the support shaft and hold the pressure differential sheet by switching between an angle in the mounting position and an angle in the standby position, and a sheet support shaft that is supported between the tips of the arm members and supports the pressure differential sheet from below.

8. 7. The vaporization treatment apparatus according to claim 6, wherein the sheet holding means comprises an arm support shaft supported at a predetermined height on left and right inner surfaces of the treatment chamber and extending in the front-rear direction, a pair of front and rear arm members that rotate around the support shaft and switch and hold the differential pressure sheet at an angle in the mounting position and an angle in the standby position, a sheet support shaft that is supported between the tips of the arm members and supports the differential pressure sheet from below, and an angle holding / release mechanism that holds the sheet support shaft at the angle in the mounting position and the angle in the standby position by a rotation operation and releases the held states of the sheet support shaft at the angle in the mounting position and the angle in the standby position during the rotation operation.

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