Vacuum packaging method and vacuum packaging apparatus

Abstract

The invention provides a vacuum packaging method and a vacuum packaging apparatus that can sufficiently degasify the inside of a packaging bag without any trouble and in which bubbles are less likely to remain inside the packaging bag after vacuum packaging, even if a liquid is included in a packaged object.

Claims

1. A vacuum packaging apparatus, comprising: a chamber that accommodates a packaging bag having an opening to insert a liquid-containing object; an air-pressure detection sensor with which an air pressure in the chamber is detected, a pump that decompresses the chamber; a decompression regulating mechanism that can select either a first decompression rate or a second decompression rate slower than the first rate; a closing device that is provided in the chamber to pinch the opening of the packaging bag such that the opening of the packaging bag is closed; a sealing device that seals the pinched opening of the packaging bag; and a controller that stores an air pressure value at the boiling point of the liquid contained in the packaging bag; detects the air pressure in the chamber using the air-pressure detection sensor; and controls the pump, the decompression regulating mechanism, the closing device, and the sealing device; wherein the controller performs decompressing the chamber accommodating the packaging bag; controlling the decompression regulating mechanism to select the second decompression rate based on the value of the air pressure stored and the air pressure detected using the air pressure detection sensor; stopping the decompression in the chamber; and sealing the opening of the packaging bag, so that the object is vacuum packaged in the packaging bag.

2. The vacuum packaging apparatus according to claim 1, wherein the controller controls the pump and the closing device based on the value of the air pressure stored and the air pressure detected by the air pressure detection sensor.

3. The vacuum packaging apparatus according to claim 2, wherein the controller controls the sealing device based on the value of the air pressure stored and the air pressure detected by the air pressure detection sensor.

4. The vacuum packaging apparatus according to claim 1, further comprising an inflation detection sensor which detects the inflation of the packaging bag, wherein the controller opens the opening of the packaging bag if the inflation detection sensor detects the inflation of the packaging bag.

5. The vacuum packaging apparatus according to claim 4, wherein the inflation detection sensor includes a bag abutting portion that abuts against an upper portion of the packaging bag and a sensor that detects a change in position of the bag abutting portion.

6. The vacuum packaging apparatus according to claim 1, further comprising a valve which brings the chamber to an atmospheric pressure, wherein the controller controls the valve to bring the chamber to the atmospheric pressure after sealing the opening of the packaging bag.

7. A vacuum packaging method of packaging a liquid-containing object in a packaging bag having an opening to insert the object, using a vacuum packaging apparatus according to claim 1, comprising the steps of: decompressing the chamber accommodating the packaging bag; controlling the decompression regulating mechanism to select the second decompression rate based on the value of the air pressure stored and the air pressure detected using the air pressure detection sensor; stopping the decompression in the chamber; and sealing the opening of the packaging bag.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a vacuum packaging apparatus.

(2) FIG. 2 is a block diagram illustrating a control system of the vacuum packaging apparatus.

(3) FIG. 3 is a water vapor pressure table.

(4) FIG. 4 is a water vapor pressure curve.

(5) FIGS. 5(a) and 5(b) illustrate explanatory drawings of the vacuum packaging apparatus that decompresses inside a chamber to a first set pressure in a preparatory decompression process, of which FIG. 5(a) is a schematic diagram and FIG. 5(b) is a timing chart.

(6) FIGS. 6(a) and 6(b) illustrate explanatory drawings of the vacuum packaging apparatus that decompresses inside the chamber to a second set pressure in the preparatory decompression process, of which FIG. 6(a) is a schematic diagram and FIG. 6(b) is a timing chart.

(7) FIGS. 7(a) and 7(b) illustrate explanatory drawings of the vacuum packaging apparatus in a package decompressing process, of which FIG. 7(a) is a schematic diagram and FIG. 7(b) is a timing chart.

(8) FIGS. 8(a) and 8(b) illustrate explanatory drawings of the vacuum packaging apparatus in a closing cancellation process, of which FIG. 8(a) is a schematic diagram and FIG. 8(b) is a timing chart.

(9) FIGS. 9(a) and 9(b) illustrate explanatory drawings of the vacuum packaging apparatus in a sealing process, of which FIG. 9(a) is a schematic diagram and FIG. 9(b) is a timing chart.

(10) FIGS. 10(a) and 10(b) illustrate explanatory drawings of the vacuum packaging apparatus after the completion of sealing process, of which FIG. 10(a) is a schematic diagram and FIG. 10(b) is a timing chart.

(11) FIG. 11 is a schematic diagram of a vacuum packaging apparatus including a temperature detection sensor.

(12) FIG. 12 is a block diagram illustrating a control system of the vacuum packaging apparatus including the temperature detection sensor.

(13) FIG. 13 is a schematic diagram of a vacuum packaging apparatus including the temperature detection sensor and an inflation detection means.

(14) FIG. 14 is a block diagram illustrating a control system of the vacuum packaging apparatus including the temperature detection sensor and the inflation detection means.

(15) FIG. 15 is a schematic diagram of the vacuum packaging apparatus in the package decompressing process including the temperature detection sensor and the inflation detection means.

(16) FIG. 16 is a schematic diagram of the vacuum packaging apparatus in the closing cancellation process including the temperature detection sensor and the inflation detection means.

MODES FOR CARRYING OUT THE INVENTION

(17) Hereinafter, modes for carrying out the invention will be described with reference to the drawings.

(18) A vacuum packaging apparatus 1, as illustrated in FIGS. 1 and 2, includes a chamber 2 that accommodates a packaging bag B in which a packaged object is received, a degasifier 3 that degasses inside the packaging bag B by decompressing inside the chamber 2, a filling-opening closing device 5 that is provided inside the chamber 2 and that closes a packaged-object filling opening Ba of the packaging bag B, sealing heaters 6 (corresponding to a sealing device of the present invention) that seals the packaged-object filling opening Ba of the packaging bag B, and a controller 7 that controls the degasifier 3, the filling-opening closing device 5, and the sealing heaters 6. Note that the degasifier 3 will be described later in detail.

(19) The chamber 2 is a pressure-resistant container that is constituted by a body portion 2a that is capable of mounting the packaging bag B on the upper surface thereof and a lid portion 2b that closes the body portion 2a from above and is configured such that the lid portion 2b is capable of being opened and closed by being pivoted in the up-down direction and such that airtightness inside the chamber 2 is maintained by providing a sealing material (not shown) at a portion where the lid portion 2b and the body portion 2a are in contact with each other. Furthermore, a suction opening 9 is drilled in the body portion 2a and is connected to the degasifier 3 such that when the degasifier 3 is driven, air inside the chamber 2 is drawn out from the suction opening 9 and the chamber 2 is decompressed inside.

(20) The filling-opening closing device 5 includes, in an opposing state, a lower side closing block 10 that is provided on the body portion 2a side in a state allowing the lower side closing block 10 to be lifted and lowered and an upper side closing block 11 that is fixed to the undersurface side of the lid portion 2b, in which the lower side closing block 10 is capable of being lifted and lowered by driving of a closing cylinder 12 and the packaged-object filling opening Ba is closed by pinching the packaging bag B between the upper side closing block 11 and the lower side closing block 10 that is in a lifted state. Furthermore, the closing cylinder 12 and the degasifier 3 are connected by a filling-opening closing drive flow path 13, and, one of the connection ports of a filling-opening closing solenoid valve 14 constituted by a three-way valve is connected to the filling-opening closing drive flow path 13, one of the remaining connection ports is connected to a portion of the degasifier 3, and the other one of the remaining connection ports is opened to the atmosphere. Moreover, by operating the filling-opening closing solenoid valve 14, the closing cylinder 12 and the degasifier 3 are brought into communication with each other such that air inside the closing cylinder 12 is suctioned with the degasifier 3, and the closing cylinder 12 elevates and presses the lower side closing block 10 against the upper side closing block 11 (see FIG. 7(a)). When the inside of the closing cylinder 12 is released to the atmosphere, the closing cylinder 12 separates the lower side closing block 10 downwards from the upper side closing block 11 (see FIG. 5(a)). Furthermore, the sealing heaters 6 are each provided on the upper side closing block 11 side (the upper portion) of the lower side closing block 10 and on the lower side closing block 10 side (the lower portion) of the upper side closing block 11, and when the sealing heaters 6 are energized while in a state in which the packaging bag B is pinched between the upper side closing block 11 and the lower side closing block 10, the packaged-object filling opening Ba are, while in the close state, heat pressure-jointed and sealed.

(21) Furthermore, a bag pinching surface (the upper surface) of the lower side closing block 10 and a bag pinching surface (undersurface) of the upper side closing block 11 are each provided with a bag adhesive portion 15 that is constituted by a gel sheet (for example, a silicone rubber sheet) that has heat resistance and adhesiveness such that the bag adhesive portions 15 are adhered to the surface of the packaging bag B so that not only a trouble in that the packaged-object filling opening Ba of the packaging bag B in the pinched state is displaced, consequently, but also a trouble in that the packaging bag B in the pinched state slips out from between the upper side closing block 11 and the lower side closing block 10 can be prevented. Note that the bag adhesive portions 15 are disposed at positions that are displaced from the sealing heaters 6 (specifically, on the pivotal center side (the right side of FIG. 1) of the lid portion 2b with respect to the sealing heater 6).

(22) Next, the degasifier 3 will be described.

(23) The degasifier 3 includes a vacuum pump 16 and a decompression regulating mechanism 17 that is connected between the vacuum pump 16 and the chamber 2. The decompression regulating mechanism 17 includes a suction-air flow path 18 that is capable of communicating the vacuum pump 16 and the chamber 2 to each other, and midway of the suction-air flow path 18, a vacuum solenoid valve 19 (a type of flow path switching valve according to the present invention) that allows or cancels communication between the vacuum pump 16 and the chamber 2 is provided. Furthermore, in the suction-air flow path 18, a chamber-side branching port 20 is provided between the chamber 2 and the vacuum solenoid valve 19, and a pump-side branching port 21 is provided between the vacuum pump 16 and the vacuum solenoid valve 19, and, the chamber-side branching port 20 and the pump-side branching port 21 are connected with a bypass flow path 22 such that the vacuum pump 16 and the chamber 2 can be in communication with each other with the bypass flow path 22 while bypassing the suction-air flow path 18. Furthermore, midway of the bypass flow path 22, a vacuum bypass solenoid valve 23 (a type of flow path switching valve according to the present invention) that allows or cancels communication between the vacuum pump 16 and the chamber 2 is provided. Moreover, the flow path diameter of the bypass flow path 22 and the orifice diameter of the vacuum bypass solenoid valve 23 are formed smaller than the flow path diameter of the suction-air flow path 18, or a throttle valve (not shown) is disposed midway of the bypass flow path 22, such that the flow path resistance of the bypass flow path 22 is set larger than that of the suction-air flow path 18.

(24) The decompression regulating mechanism 17 (the degasifier 3) provided with such a configuration is, by operating the vacuum solenoid valve 19 and the vacuum bypass solenoid valve 23, capable of switching the communication state between the vacuum pump 16 and the chamber 2. Specifically, when the vacuum solenoid valve 19 is opened and the vacuum bypass solenoid valve 23 is closed, a suction-air communicating state, which is a state in which the vacuum pump 16 and the chamber 2 are in communication with each other through the suction-air flow path 18 without passing the bypass flow path 22, is achieved (see FIG. 5(a)), and when the vacuum solenoid valve 19 is closed and the vacuum bypass solenoid valve 23 is opened, a bypass communicating state, which is a state in which the vacuum pump 16 and the chamber 2 are in communication with each other through the bypass flow path 22 without passing through the suction-air flow path 18, is achieved. Moreover, when the vacuum solenoid valve 19 and the vacuum bypass solenoid valve 23 are operated and are switched to the suction-air communicating state and, in this state, when the chamber 2 is decompressed inside by driving the vacuum pump 16, the chamber 2 is decompressed inside at a first decompression rate that has been set in advance. On the other hand, when the vacuum solenoid valve 19 and the vacuum bypass solenoid valve 23 are operated and are switched to the bypass communicating state and when, in this state, the chamber 2 is decompressed inside by driving the vacuum pump 16, the chamber 2 is decompressed inside at a second decompression rate that is slower than the first decompression rate. In other words, the decompression regulating mechanism 17 is configured such that the decompression rate in the chamber 2 decompressed by driving of the vacuum pump 16 can be switched between the first decompression rate that has been set in advance and the second decompression rate that is slower than the first decompression rate.

(25) Note that, in the suction-air flow path 18, a portion positioned between the pump-side branching port 21 and the vacuum pump 16 is provided with a closing branching port 25, and one of the connection ports of the filling-opening closing solenoid valve 14 is connected to the closing branching port 25. Furthermore, in the suction-air flow path 18, a portion between the chamber-side branching port 20 and the chamber 2 is provided with a vacuum releasing branching port 26, and a vacuum releasing valve 27 is connected thereto such that the inside of the chamber 2 can be returned to atmospheric pressure (can perform atmospheric release) from the decompressed state by opening the vacuum releasing valve 27.

(26) The controller 7 includes, as illustrated in FIG. 2, a one-chip microcomputer 30 that performs control of the vacuum packaging apparatus 1, an interface circuit 31 that performs input-output processes of various signals, and the like. Moreover, the interface circuit 31 is input with signals from various operation switches such as a power switch 32, configuration switches 33 for pressure and time, and the like that are provided in the control panel (not shown) of the vacuum packaging apparatus 1, an air-pressure detection sensor (pressure sensor) 34 that detects the air pressure inside the chamber 2, and a lid open-close detection sensor 35 that detects the open-closed state of the lid portion 2b. Furthermore, the interface circuit 31 outputs control signals to the vacuum pump 16, the vacuum solenoid valve 19, the vacuum bypass solenoid valve 23, the filling-opening closing solenoid valve 14, the vacuum releasing valve 27, the sealing heaters 6, a buzzer 36 that sounds various alarm sounds, and an indicator 37 that indicates various statuses. Moreover, target values of the air pressure. (a first set pressure P1 (corresponding to a preparatory set pressure according to the present invention), a second set pressure P2 (corresponding to a before-closing-filling-opening set pressure according to the present invention) that is lower than the first set pressure P1, a third set pressure P3 (corresponding to a when-opening-filling-opening set pressure according to the present invention) that is lower than the second set pressure P2)) inside the chamber 2 during the vacuum packaging operation are set in advance by, for example, an operator performing input operations with the configuration switches 33, and the operation of the vacuum packaging apparatus 1 is controlled while the air pressure detected by the air-pressure detection sensor 34 reaching the first set pressure P1, the second set pressure P2, and the third set pressure P3 serve as triggers.

(27) Next, in the vacuum packaging apparatus 1 with the configuration described above, a process of vacuum packaging a packaged object that includes a liquid that has a temperature that is higher than a normal temperature will be described. Note that in this embodiment, the liquid that is included in the packaged object is water that has a temperature that is higher (for example 80° C.) than the normal temperature. Furthermore, in a state before the start of the vacuum packaging (a normal state), the vacuum pump 16 is not driven, all the connection ports of the vacuum solenoid valve 19, the vacuum bypass solenoid valve 23, and the filling-opening closing solenoid valve 14 are in a closed state (N, C), and the vacuum releasing valve 27 is in an open state (N, O) (see FIG. 5(b)). Furthermore, the inside of the filling-opening closing drive flow path 13 and the inside of the closing cylinder 12 are not decompressed and the lower side closing block 10 is in a lowered state. Moreover, the target values (the first set pressure P1, the second set pressure P2, and the third set pressure P3) of the air pressure inside the chamber 2 during the vacuum packaging operation are set in advance on the basis of temperatures of the liquid (water) included in the packaged object. Specifically, the operator performs input operations with the configuration switches 33, for example, to set the second set pressure P2 at a pressure that boils the water that has a high temperature included in the packaged object (specifically, the pressure at which boiling starts). For example, when the water temperature is 80° C., the second set pressure P2 is set at 47.39 kPa (see FIGS. 3 and 4). Furthermore, in advance, the first set pressure P1 is set higher than the second set pressure P2 (for example, 10 kPa higher than the second set pressure P2) at a pressure at which the water that has a high temperature included in the packaged object does not boil, and the third set pressure P3 is set lower than the second set pressure P2 (for example, 10 kPa lower than the second set pressure P2) at a pressure at which the water that has a high temperature included in the packaged object boils.

(28) First, a setting process (a preparation process) of setting the packaging bag B filled with the packaged object inside the chamber 2 is performed. In the setting process, while the lid portion 2b is in an open state, the operator mounts the packaging bag B on the body portion 2a and mounts the packaged-object filling opening Ba on the lower side closing block 10. After setting the packaging bag B, when the lid portion 2b is manually closed, the lid open-close detection sensor 35 detects the closed state of the lid portion 2b and sends a signal to the controller 7.

(29) When the controller 7 receives the detection signal of the closed state of the lid portion 2b, the process proceeds to a preparatory decompression process. In the preparatory decompression process, the controller 7 functions as preparatory decompression control means and controls the decompression operation inside the chamber 2. Specifically, as illustrated in FIGS. 5(a) and 5(b), the vacuum solenoid valve 19 is opened and the closed state of the vacuum bypass solenoid valve 23 is maintained such that the decompression regulating mechanism 17 is in a suction-air communicating state, and the vacuum releasing valve 27 is closed. Furthermore, in the filling-opening closing solenoid valve 14, while the connection port on the atmospheric releasing side and the connection port on the filling-opening closing drive flow path 13 side are open, the closed state of the connection port on the closing branching port 25 side is maintained. Upon completion of the operation of each of the solenoid valves 14, 19, and 23 and the vacuum releasing valve 27, the vacuum pump 16 is driven and decompression inside the chamber 2 is started such that degassing inside the packaging bag B is performed. At this time, since the air inside the chamber 2 passes through the suction-air flow path 18 and is drawn into the vacuum pump 16, the chamber 2 is decompressed inside at the first decompression rate. Then, the air-pressure detection sensor 34 detects the air pressure inside the chamber 2 and transmits a detection signal to the controller 7, and when the controller 7 determines that the air pressure inside the chamber 2 is decompressed to the preset first set pressure P1, the controller 7, as illustrated in FIGS. 6(a) and 6(b), keeps on driving the vacuum pump 16, maintains the open-closed state of each connection port of the filling-opening closing solenoid valve 14 and the closed state of the vacuum releasing valve 27, and closes the vacuum solenoid valve 19 and opens the vacuum bypass solenoid valve 23 so as to switch the decompression regulating mechanism 17 to the bypass communicating state. With the above, since the air inside the chamber 2 passes through the bypass flow path 22 and is drawn into the vacuum pump 16, the chamber 2 is decompressed inside at the second decompression rate that is slower than the first decompression rate. Accordingly, a trouble in that the packaging bag B being rapidly decompressed inside generating bumping of the liquid can be averted.

(30) While the chamber 2 is continuously decompressed inside at the second decompression rate, when it is detected by the air-pressure detection sensor 34 that the chamber 2 is decompressed inside to the second set pressure P2 that is lower than the first set pressure P1, the process proceeds to a package decompressing process. In the package decompressing process, the controller 7 functions as a package decompression control means and controls the decompression operation and the closing operation of the packaged-object filling opening Ba inside the chamber 2. Specifically, as illustrated in FIGS. 7(a) and 7(b), the driving of the vacuum pump 16, the bypass communicating state (the closed state of the vacuum solenoid valve 19 and the open state of the vacuum bypass solenoid valve 23) of the decompression regulating mechanism 17, and the closed state of the vacuum releasing valve 27 are maintained. Furthermore, in the filling-opening closing solenoid valve 14, the connection port on the atmospheric releasing side is closed and the connection port on the filling-opening closing drive flow path 13 side and the connection port on the closing branching port 25 side are opened such that the air inside the closing cylinder 12 is suctioned; accordingly, the lower side closing block 10 is lifted and the packaging bag B is pinched between the upper side closing block 11 and the lower side closing block 10 such that the packaged-object filling opening Ba is closed. Moreover, in the chamber 2 that has been decompressed inside to the second set pressure P2, the liquid (water) inside the packaged object starts to boil and due to the gas (water vapor) generated by the vaporized liquid, the air pressure inside the packaging bag B becomes higher than the air pressure inside the chamber 2 and the packaging bag B becomes inflated. At this time, because the packaged-object filling opening Ba is closed by the filling-opening closing device 5, even if the second set pressure P2 is set at a pressure at which the liquid boils in a high temperature state inside the packaging bag B, in other words, even if sufficient degassing inside the packaging bag B is attempted by decompressing inside the chamber 2 to a pressure at which the liquid boils, a trouble in that the boiling liquid boils out from the packaging bag B can be avoided and, accordingly, the packaged-object filling opening Ba can be prevented from becoming dirty from liquid. Accordingly, even if a liquid is included in the packaged object, it is possible to sufficiently degasify inside the packaging bag B without any trouble; accordingly, bubbles are less likely to remain inside the packaging bag B after the vacuum packaging and it is possible to perform the vacuum packaging in a desirable manner. Furthermore, it is less likely for the gas that has been generated by vaporization of the boiling water to be drawn into the vacuum pump 16; accordingly, it is possible to suppress a defect from occurring in the vacuum pump 16 due to drawing in the generated gas. Furthermore, since the packaging bag B is pinched in an adhesive manner between the bag adhesive portions 15 that are each provided on the upper side closing block 11 and the lower side closing block 10, even if the packaging bag B becomes inflated due to boiling of the liquid, the packaged-object filling opening Ba is not displaced; accordingly, a trouble such as the packaging bag B in a pinched state slipping out from between the upper side closing block 11 and the lower side closing block 10 can be prevented and, consequently, unintended opening of the packaged-object filling opening Ba leading to a trouble such as the liquid boiling out can be prevented.

(31) While the driving of the vacuum pump 16 is continued under the state in which the packaged-object filling opening Ba is closed, the chamber 2 is decompressed inside at the second decompression rate so as to keep the liquid inside the packaged object boiling, and when the air-pressure detection sensor 34 detects that the chamber 2 is decompressed inside to the third set pressure P3, the process proceeds to a closing cancellation process. In the closing cancellation process, the controller 7 functions as a closing cancellation control means and controls the operation of the decompression regulating mechanism 17 and the closing cancellation operation (releasing operation) of the packaged-object filling opening Ba. Specifically, as illustrated in FIGS. 8(a) and 8(b), while the closed state of the vacuum releasing valve 27 and the vacuum solenoid valve 19 is maintained, the vacuum bypass solenoid valve 23 is closed so as to stop degassing inside the chamber 2 (block the airflow between the chamber 2 and the vacuum pump 16) and to maintain the state in which decompression has been performed to the third set pressure P3. Moreover, the driving of the vacuum pump 16 is maintained for the next process, and in the filling-opening closing solenoid valve 14, the connection port on the closing branching port 25 side is closed and the connection port on the atmospheric releasing side is opened so that the inside of the closing cylinder 12 is released to the atmosphere; accordingly, the lower side closing block 10 is lowered and is separated from the upper side closing block 11 and the packaged-object filling opening Ba of the packaging bag B in the inflated state inside the chamber 2 decompressed to the third set pressure P3 is released, in other words, the closed state of the packaged-object filling opening Ba is canceled. With the above, gas that has been generated inside the packaging bag B is emitted into the chamber 2 through the packaged-object filling opening Ba and, further, the residue air that had not been drawn out (degassed) from inside the packaging bag B in the preparatory decompression process and the package decompressing process is also emitted to the outside of the packaging bag B together with the gas. At this time, since the bag adhesive portions 15 are adhered to the surface of the packaging bag B, even if the inside surfaces of the packaged-object filling opening Ba in the closed state are adhered to each other by liquid included in the packaged object, the packaged-object filling opening Ba can be smoothly opened and released.

(32) Upon release of the packaged-object filling opening Ba and emission of the gas and the residue air from the packaging bag B, the process proceeds to a sealing process. In the sealing process, the controller 7 functions as sealing control means and controls the reclosing operation of the packaged-object filling opening Ba. Specifically, as illustrated in FIGS. 9(a) and 9(b), the closed state of the vacuum releasing valve 27, the vacuum solenoid valve 19, and the vacuum bypass solenoid valve 23 is maintained and the decompress state inside the chamber 2 is maintained. Furthermore, the driving of the vacuum pump 16 is maintained and, in the filling-opening closing solenoid valve 14, while the open state of the connection port on the filling-opening closing drive flow path 13 side is maintained, the connection port on the atmospheric releasing side is closed and the connection port on the closing branching port 25 side is opened such that the air inside the closing cylinder 12 is suctioned; accordingly, the lower side closing block 10 is lifted again and the packaging bag B is pinched between the upper side closing block 11 and the lower side closing block 10 such that the packaged-object filling opening Ba is closed again. When the packaged-object filling opening Ba is closed again, in this state, the sealing heaters 6 are energized and the packaged-object filling opening Ba in the closed state is heated so as to be heat sealed (sealed).

(33) When the heat sealing of the packaged-object filling opening Ba is completed, energization of the sealing heaters 6 is stopped and the pinched state created by the filling-opening closing device 5 is maintained until a cooling time of the packaged-object filling opening Ba elapses. Moreover, after the elapse of the cooling time, as illustrated in FIGS. 10(a) and 10(b), in the filling-opening closing solenoid valve 14, the connection port on the closing branching port 25 side is closed and the connection port on the atmospheric releasing side is opened so that the inside of the closing cylinder 12 is released to the atmosphere; accordingly, the lower side closing block 10 is lowered and is separated from the upper side closing block 11, and pinching of the packaging bag B in the sealed state is canceled. Furthermore, the vacuum releasing valve 27 is opened so as to return the inside of the chamber 2 to atmospheric pressure, and after stopping the driving of the vacuum pump 16, an alarm sound is generated by the buzzer 36 to notify the end of the vacuum packaging.

(34) Note that even if bubbles are generated inside the packaging bag B immediately after the end of the vacuum packaging, most of the bubbles are not residue air but are the liquid included in the packaged object that has been vaporized. Accordingly, when the packaged object is cooled to the normal temperature, the bubbles are condensed inside the packaging bag B and returns to liquid. As a result, even if there is a packaged object that includes liquid, it is possible to obtain a desirably vacuumed package that has scarcely any bubble.

(35) In the vacuum packaging performed in the above manner, since the second set pressure P2 is set at a pressure at which the liquid included in the packaged object boils under the temperature when accommodated inside the packaging bag B, it is possible to force the air inside the packaging bag B to the outside with the gas generated through vaporization of the boiled liquid; accordingly, the packaging bag B can be sufficiently degassed inside. Accordingly, it is possible to perform vacuum packaging in a desirable manner that is less likely to contain residue air (in other words, with scarcely any bubble). Furthermore, since the decompression regulating mechanism 17 of the vacuum packaging apparatus 1 is constituted by the suction-air flow path 18, the bypass flow path 22, the vacuum solenoid valve 19, and the vacuum bypass solenoid valve 23, the decompression regulating mechanism 17 can be made with a simple configuration. Note that in the embodiment described above, while the second set pressure P2 is set at a pressure at which the liquid starts to boil, the present invention is not limited to this setting. For example, a pressure that is lower than the pressure at which the liquid starts to boil may be the second set pressure P2.

(36) Incidentally, in the above-described embodiment, the first to third set pressures are set by input operations on the control panel (configuration switches 33 and the like); however, the present invention is not limited to this. For example, before the main operation (before the actual vacuum packaging operation) of the vacuum packaging apparatus 1, a trial operation (sampling) may be performed in order to obtain data of each set pressure while the operator monitors the state of the liquid inside the packaging bag B, and, when the operator operates the control panel at the point when the liquid boils, the air-pressure detection sensor 34 may detect the pressure at the boiling point and store the pressure as the second set pressure P2. Furthermore, the stored second set pressure P2 may be added with or subtracted by preset pressure differences such that the third set pressure P3 and the first set pressure P1 are calculated and stored, and, each of the stored set pressures may be used to perform the main operation of the vacuum packaging apparatus 1.

(37) Furthermore, temperatures of the packaged object inside the packaging bag B accommodated in the chamber 2 may be allowed to be detected and the detected temperature and data, which has been stored in advance in the controller 7, may be compared in order to set each of the set pressures. For example, in a second embodiment illustrated in FIGS. 11 and 12, the lid portion 2b of the chamber 2 is provided with a temperature detection sensor 40 that is capable of detecting, in a contactless manner, the temperature of the packaged object inside the packaging bag B accommodated in the chamber 2, and information of the temperature detected by the temperature detection sensor 40 is, as a signal, capable of being transmitted to the interface circuit 31 of the controller 7. Furthermore, in the controller 7, data of a boiling start pressure table (for example, data of a water vapor pressure table illustrated in FIG. 3) that sets forth the correlation between the temperature of the liquid (for example, water) included in the package object and the pressure at which the liquid with the above temperature starts to boil is stored in advance.

(38) Note that the installing position of the temperature detection sensor 40 is, provided that the temperature of the packaged object inside the packaging bag B can be detected, not limited to the lid portion 2b. Furthermore, in the second embodiment, the surface temperature of the packaging bag B, in which the packaged object is received, is detected by the temperature detection sensor 40 and the detection temperature is processed as the temperature of the packaged object; however, it goes without saying that the temperature of the packaged object may be directly detected by having the temperature detection sensor come in contact with the packaged object. However, if the packaged object is a foodstuff, it is desirable that the noncontact type temperature detection sensor is adopted.

(39) In the vacuum packaging apparatus 1 provided with such a configuration, after setting the packaging bag B inside the chamber 2 during the setting process, the lid portion 2b is closed, and when the lid open-close detection sensor 35 detects the closed state of the lid portion 2b and sends a signal to the controller 7, the temperature detection sensor 40 detects the temperature of the packaged object inside the packaging bag B and transmits information of the detected temperature to the controller 7. Then, the controller 7 having received the temperature information refers to the data in the boiling start pressure table and determines the pressure at which the liquid having the detection temperature of the package object starts to boil as the second set pressure P2, and further, adds and subtracts the preset temperature differences to and from the second set pressure P2 so as to set the third set pressure P3 and the first set pressure P1. Furthermore, the temperature detected by the temperature detection sensor 40 and each of the set pressures set by the controller 7 are indicated on the indicator 37 of the control panel.

(40) As described above, by detecting the temperature of the packaged object inside the chamber 2 and setting each of the set pressures on the basis of the detection temperature, even if the temperature of the packaged object is different each time the vacuum packaging operation is performed, each of the set pressures suitable for the packaged object, in other words, the operation of the vacuum packaging apparatus 1 suitable for the packaged object, can be set; accordingly, it is possible to perform a vacuum packaging operation in which liquid is not easily boiled out.

(41) Note that in the above-described second embodiment, instead of storing the data of the boiling start pressure table in the controller 7, and arithmetic expression that calculates the pressure at which the liquid starts to boil from the temperature of the liquid may be installed such that when information of the temperature of the liquid is input to the controller 7 from the temperature detection sensor 40, the controller 7 may calculate the pressure using the arithmetic expression and set the second set pressure P2. Furthermore, a numerical value after adding or subtracting a preset correction pressure difference to or from the pressure (the pressure at which the liquid starts to boil) that has been determined or calculated on the basis of the temperature information of the liquid may be set as the second set pressure P2.

(42) Incidentally, in each of the above-described embodiments, when the chamber 2 is decompressed inside to the third set pressure P3 that has been set in advance, degassing inside the chamber 2 is stopped; however, the present invention is not limited to this configuration. For example, in a third embodiment illustrated in FIG. 13, while basically similar to the second embodiment, the third set pressure is not set, and, alternatively, the inflated state of the packaging bag B (specifically, the packaging bag B in which the liquid is boiling inside) is detected and on the basis of the detection result, degassing inside the chamber 2 is stopped.

(43) Specifically described, as illustrated, in FIG. 13, in the chamber 2 of the vacuum packaging apparatus 1 according to the third embodiment, an inflation detection means 50 that is capable of detecting the inflated state of the packaging bag B is provided. The inflation detection means 50 includes a tabular bag abutting portion 51 that is placed on the body portion 2a and that is positioned above the packaging bag B, and an inflation detection sensor 52 that is capable of detecting the inflated state of the packaging bag B by the change in position of the bag abutting portion 51. Moreover, the bag abutting portion 51 is configured such that an end portion (a left end portion in FIG. 13) of the bag abutting portion 51 on the filling-opening closing device 5 side is pivotally attached to a side portion of the upper side closing block 11 in a pivotal manner and a free end portion positioned on the pivotally attached side of the lid portion 2b (the right end portion in FIG. 13) is lifted and lowered (moved in the up-down direction) such that the free end portion can be changed between a lifted position (the position illustrated by the solid line in FIG. 13) in which the free end portion is positioned on the lid portion 2b side and a lowered position (the position illustrated by the two-dot chain line in FIG. 13) in which the free end portion is positioned on the body portion 2a side. Furthermore, in the bag abutting portion 51, an opening portion (not shown) that makes the temperature detection sensor 40 face the packaging bag B is open so as to prevent the temperature detection sensor 40 from erroneously detecting the temperature of the bag abutting portion 51.

(44) Furthermore, a detection piece 53 is provided on the upper surface (the surface facing the lid portion 2b side) of the free end portion of the bag abutting portion 51, and a stopper 54 that prevents the free end portion from abutting against the body portion 2a is provided on the undersurface. Moreover, in the chamber 2, at a portion above the detection piece 53, the inflation detection sensor 52 that is capable of detecting the detection piece 53 of the bag abutting portion 51 in the lifted position is provided such that the detection signal of the inflation detection sensor 52 can be transmitted to the interface circuit 31 of the controller 7 (see FIG. 14). Note that in the present embodiment, the inflation detection sensor 52 is constituted by a magnetic sensor and the detection piece 53 is constituted by a magnetic body, and the strength of the magnetic field changed by approach of the detection piece 53 is detected by the inflation detection sensor 52; accordingly, change in position of the bag abutting portion 51 can be detected.

(45) In the package decompressing process of the vacuum packaging apparatus 1 including the inflation detection means 50 configured as above, as illustrated in FIG. 15, inside the chamber 2 that has been decompressed to the second set pressure P2, inside the packaging bag B in a state in which the packaged-object filling opening Ba is closed, the liquid (water) inside the packaged object starts to boil and due to the gas (water vapor) generated by the vaporized liquid, the air pressure inside the packaging bag B becomes higher than the air pressure inside the chamber 2 and the packaging bag B becomes inflated. Then, on the basis of the control of the controller 7 serving as the package decompression control means, when the driving of the vacuum pump 16 is continued while the packaged-object filling opening Ba is in a closed state and when boiling of the liquid inside the packaged object is continued while decompressing inside the chamber 2 at the second decompression rate, the upper surface of the inflated packaging bag B abuts against the bag abutting portion 51. When the driving of the vacuum pump 16 is further continued and when the packaging bag B is further inflated, the bag abutting portion 51 is pushed up by the packaging bag B and is changed to the lifted position from the lowered position such that the detection piece 53 of the bag abutting portion 51 at the lifted position is detected by the inflation detection sensor 52.

(46) When the controller 7 receives a detection signal implying that the detection piece 53 has been detected by the inflation detection sensor 52 (in other words, a detection signal implying that the inflation of the packaging bag B has been detected), the vacuum packaging apparatus 1 proceeds to the closing cancellation process and the controller 7 functions as a closing cancellation control means. Then, as illustrated in FIG. 16, degassing inside the chamber 2 is stopped (airflow between the chamber 2 and the vacuum pump 16 is blocked) and the lower side closing block 10 is lowered and is separated from the upper side closing block 11 so as to release the packaged-object filling opening Ba of the packaging bag B in the inflated state, in other words, the closed state of the packaged-object filling opening Ba is canceled. With the above, gas that has been generated inside the packaging bag B is emitted into the chamber 2 through the packaged-object filling opening Ba and, further, the residue air that had not been drawn out (degassed) from inside the packaging bag B in the preparatory decompression process and the package decompressing process is also emitted to the outside of the packaging bag B together with the gas. Furthermore, the bag abutting portion 51 that had been changed to the lifted position by the inflation of the packaging bag B moves downwards by its own weight and returns to the lowered position, and squashes the inflated packaging bag B. With the above, residue gas (air and the gas) that remains inside the packaging bag B can be forced to the outside by using the configuration that detects the inflated state of the packaging bag B and the inside of the packaging bag B can be degassed sufficiently. Accordingly, it is possible to perform vacuum packaging in a desirable manner that is less likely to contain residue air.

(47) Furthermore, since degassing inside the chamber 2 is stopped when the inflated state of the packaging bag B is detected, it is easy to understand the timing to stop degassing inside the chamber 2 on the basis of the inflation of the packaging bag B, in other words, the boiling state of the liquid. Accordingly, a trouble such as excessive decompression inside the chamber 2 and, consequently, a trouble in that a large amount of vapored gas, which is the result of excessive boiling of the liquid inside the packaging bag B, being drawn into the degasifier 3 (specifically, the vacuum pump 16) can be avoided.

(48) Note that the bag abutting portion 51 is not limited to the configuration in which a flat plate is pivotally attached to the upper side closing block 11. The point is, any configuration may be adopted as long as the bag abutting portion 51 is disposed inside the chamber 2 and above the packaging bag B so as to be allowed to be lifted and lowered, is lifted up by the inflated packaging bag B, and is capable of being placed on the upper surface of the packaging bag B in the inflated state and squashing the packaging bag B. For example, the bag abutting portion 51 may be a member that can be lifted and lowered along a columnar slide guide that is provided in an erect manner inside the chamber 2, or may be a member that is hanged down from inside the lid portion 2b with a chain, a rope, or the like. Furthermore, the bag abutting portion may be configured to be biased at all times to the packaging bag B side therebelow with a biasing force of a biasing member such as a spring or the like such that in the package decompressing process, the inflating packaging bag B resists the biasing force of the biasing member and lifts the bag abutting portion up, and in the closing cancellation process, the bag abutting portion squashes the packaging bag B in the inflated state with the biasing force of the biasing member. Furthermore, the inflation detection sensor 52 is not limited to a magnetic sensor but may be any component that can detect the change in the state of the bag abutting portion 51 that is associated with the inflation of the packaging bag B. For example, the inflation detection sensor may be constituted by a mechanical sensor such as a micro switch.

(49) Furthermore, the inflation detection means is not limited to a configuration including a bag abutting portion as long as the inflation of the packaging bag B can be detected in the package decompressing process. For example, the inflation detection means may be means (detecting means based on image recognition) that is provided with a monitoring camera that takes a picture of the packaging bag B inside the chamber 2, stores data of an image of the packaging bag B in the inflated state taken in advance in the controller 7, and compares the image of the packaging bag B taken by the monitoring camera and the data so as to detect the inflated state of the packaging bag B.

(50) Incidentally, in each of the above-described embodiments, after the chamber 2 is decompressed inside to the first set pressure at the first decompression rate, decompression is performed at the second decompression rate that is slower than the first decompression rate; however, the present invention is not limited to this configuration. If no trouble during the vacuum packaging process such as bumping of the liquid occurs before reaching the second set pressure (before-closing-filling-opening set pressure) P2, the chamber 2 may be decompressed inside to the second set pressure P2 at a constant decompression rate. In other words, without performing the preparatory decompression process, the vacuum packaging process may be performed through the package decompressing process, the closing cancellation process, and the sealing process.

(51) Furthermore, in each of the above-described embodiments, the sealing heater 6 and the bag adhesive portion 15 are provided on each of the upper side closing block 11 and the lower side closing block 10 such that the filling-opening closing device and the sealing device according to the present invention are integrally formed; however the present invention is not limited to this configuration. The point is, it is only sufficient that the filling-opening closing device that closes the packaged-object filling opening, and the sealing device that seals the packaged-object filling opening are provided in the vacuum packaging apparatus and, for example, the filling-opening closing device and the sealing device may be provided separately inside the chamber 2. Furthermore, the decompression regulating mechanism 17 is configured so as to include the suction-air flow path 18 and the bypass flow path 22; however, the present invention is not limited to this configuration. The point is, the decompression regulating mechanism may be made by any configuration as long as the decompression rate inside the chamber decompressed by the driving of the vacuum pump can be controlled. Furthermore, an example has been illustrated in which the liquid included in the packaged object is water having a high temperature rather than a normal temperature; however, the present invention is not limited to this configuration. The liquid included in the packaged object may be a liquid composed of a component other than water and, for example, may be edible oil for soaking a foodstuff or may be a liquid (formalin or the like in which a biological specimen is immersed) other than foodstuffs. Furthermore, the temperature of the liquid may be at a normal temperature or lower.

(52) Furthermore, the vacuum packaging apparatus according to each of the above-described embodiments may be configured to allow a conventional vacuum packaging process (a vacuum packaging process that decompresses at a constant decompressing rate and that does not close and release the packaged-object filling opening before sealing) to be carried out, and when a packaged object including a liquid (for example, a liquid having a normal temperature) that has no risk of bumping is vacuum packaged, the conventional vacuum packaging process may be allowed to be performed by changing the settings with the operation of the control panel by the user.

REFERENCE SIGNS LIST

(53) 1 vacuum packaging apparatus 2 chamber 2a body portion 2b lid portion 3 degasifier 5 filling-opening closing device 6 sealing heater 7 controller 9 suction opening 10 lower side closing block 11 upper side closing block 12 closing cylinder 13 filling-opening closing drive flow path 14 filling-opening closing solenoid valve 15 bag adhesive portion 16 vacuum pump 17 decompression regulating mechanism 18 suction-air flow path 19 vacuum solenoid valve 20 chamber-side branching port 21 pump-side branching port 22 vacuum bypass flow path 23 vacuum bypass solenoid valve 25 closing branching port 26 vacuum releasing branching port 27 vacuum releasing valve 30 one-chip microcomputer 31 interface circuit 32 power switch 33 configuration switch 34 air-pressure detection sensor 35 lid open-close detection sensor 36 buzzer 37 indicator 40 temperature detection sensor 50 inflation detection means 51 bag abutting portion 52 inflation detection sensor 53 detection piece 54 stopper B packaging bag Ba packaged-object filling opening