METHOD AND APPARATUS FOR MAKING SMOKED FOOD

Abstract: A chamber (11) has an entrance (11a) and an exit (11b) at its ends, and conveyor means (12) is set up between the entrance and the exit in this chamber (11). The conveyor means carries a plurality of objects (19) at predetermined intervals. In the chamber, the conveyor means is positioned between a pair of electrode plates (13) in such a manner that the objects are not in touch with the electrodes. A smoking means (16) emits smoke into the chamber to smoke the objects. A high-voltage generation circuit applies DC or AC voltage of 7 to 15 kV between the electrode plates, and the objects are grounded. According to this method, a low-power smoking apparatus is provided to uniformly smoke objects and produce smoked foods of high quality.

Description: The present invention relates to a method and an apparatus therefore for adhering smoke to farm products, marine products and livestock products or processed foods thereof and for infiltrating the smoke into them, to thereby manufacture smoked foods. More particularly, the present invention relates to a method and an apparatus therefore for adhering smoke to the aforementioned farm products and the like and for infiltrating the smoke into them, by utilizing a Coulomb force between the farm products and the like and the smoke electrified within an electric field. BACKGROUND ART There has been known a conventional electrical smoking method in which a pair of electric wires mutually separated by a predetermined distance are arranged within a chamber, works such as fish and meat are hung from the electric wires, a direct current or alternating current of a higher voltage (10 kV to 20 kV) is applied across the electric wires to thereby generate corona discharge, and furthermore, smoke is generated from a fire grate at the bottom of the chamber. There has been known another conventional electrical smoking method in which a pair of mutually opposed electrodes are arranged within a chamber, works such as fish and meat are arranged between the pair of electrodes, a higher voltage (such as 40 kV) is applied across the electrodes, and smoke generated by smoke generating means is introduced into the chamber. In each of the aforementioned electrical smoking method, the smoke generated by the fire grate or the smoke generating means is supplied with ions thanks to the corona discharge, so that the thus electrified smoke is attracted to the work acting as an electrode. This results in rapid adherence and infiltration of the smoke to and into the work, to thereby provide a smoked food having a superior storage characteristic. However, the aforementioned electrical smoking methods utilize an electric field within a corona discharged area, thereby causing a problem of an extremely large amount of electric power consumption and an enlarged size of the apparatus. Further, in each of the aforementioned electrical smoking methods, since the corona discharge is conducted between the electrodes and the work, the smoke ununiformly adheres to and infiltrates into the work, thereby causing a problem of a deteriorated quality of the smoked food. Document US 2 565 454 discloses an electrostatic smoking device, which operates continuously and where foods to be smoked are conveyed between vertical plates to which a high voltage of e.g., 12 kV, is applied. Shelves and the metal cans of foods thereon are at ground potential. Smoke-laiden air is supplied to an enclosure and is caused to flow through an ionizing structure and a collecting structure. The smoke particles move to foods and are deposited thereon. This document shows another form of smoking apparatus for smoking in a continuous manner. Metallic plates are connected to the positive or ungrounded terminal of a high voltage direct current source. Foods 48 are connected to the grounded or negative terminal and are conveyed in a continuous manner between adjacent pairs of plates The smoke particles are charged positively by the ionizing structure 2, then passing upwardly into the field between plates 37 and grounded foods 48, which field causes such particles to move to and be precipitated on the foods 48. In that disclosure, the electrode plates are all connected to the same terminal of the power source while foods are grounded or connected to the opposite terminal. In the region between a pair of electrode plates lacking of foods, an electrostatic field from one electrode plate could conflict with the one from the other electrode plate to thereby form the zero potential in this region. The effect of smoking foods is thus lowered because of the existence of this region. It is therefore a first object of the present invention to provide a smoking method and an apparatus therefor capable of reducing the amount of electric power consumption and of downsizing the apparatus. It is a second object of the present invention to provide a smoking method and an apparatus therefor capable of uniformly adhering and infiltrating smoke to and into a work such as a farm product to thereby improve the quality of the smoked food. It is a third object of the present invention to provide a smoking method and an apparatus therefor capable of improving an efficiency of adherence and infiltration of smoke to and into a work, to thereby effectively utilize the smoke and finish the work into a delicious smoked food. DISCLOSURE OF INVENTION There will be described the constitution of the present invention for achieving the above objects. The invention according to claim 1, as shown in FIGS. 1 and 3, is a smoking method comprising the steps of: transporting grounded works 19 at a predetermined speed into a chamber 11 by transporting means 12, the works 19 comprising farm products, marine products and livestock products or processed foods thereof, and applying a DC voltage or AC voltage of 7 kV to 15 kV between a pair of electrode plates 13, 14 disposed along the transporting means 12 within the chamber 11 so as to interpose the work 19 between the pair of electrode plates 13, 14, so as not to start discharge. According to the smoking method recited in claim 1, application of the voltage between the pair of electrode plates 13, 14 leads to generation of an electric field incapable of initiating discharge between the pair of electrode plates 13, 14 to thereby electrify the smoke, and the thus electrified smoke adheres to and infiltrates into works 19 by a Coulomb force based on the electric potential difference between the pair of electrode plates 13, 14. Further, since no discharge such as corona discharge is initiated between the electrode plates 13, 14 and works 19, the electrified smoke uniformly adheres to and infiltrates into the works 19. The invention according to claim 2 is a smoking method according to claim 1, wherein an electrically insulative curtain 18 in reed screen shapes is attached to an inlet 11a and an exit 11b of the chamber 11, respectively. According to the smoking method described in claim 2, the curtain 18 can prevent a worker from putting his/her hand into the chamber 11. The invention according to claim 3 is a smoking method of claim 1, characterized in that the distance between the electrode plate and work adjacent to the electrode plate is 20 mm to 100 mm. According to the smoking method recited in claim 3 there can be more assuredly prevented initiation of discharge such as corona discharge or streamer discharge between the adjacent electrode plate and work. The invention according to claim 4, as shown in FIGS. 1 and 3, is a smoking apparatus comprising: a chamber 11 having opposite ends thereof formed with an inlet 11a and an exit 11b, respectively, transporting means 12 moved into the chamber 11 from the inlet 11a toward the exit 11b, and adapted to transport a plurality of works 19 spaced at predetermined intervals, the works 19 comprising farm products, marine products and livestock products or processed foods thereof, a pair of electrode plates 13, 14 disposed within the chamber 11 at predetermined distances from the works 19, respectively, along the longitudinal direction of the transporting means 12 so as to interpose the works 19 between the pair of electrode plates 13, 14, smoke generating means 16 for generating smoke to be adhered to and infiltrated into the works 19, and for introducing the smoke into the chamber 11, and a high voltage generating circuit 17 adapted to apply a DC voltage or AC voltage of 7 kV to 15 kV between the pair of electrode plates 13, 14 so as not to start discharge, and adapted to ground the works 19. According to the smoking apparatus as recited in claim 4 similarly to the invention according to claim 1, there is generated an electric field incapable of initiating discharge between the pair of electrode plates 13, 14 to thereby electrify the smoke, and the thus electrified smoke adheres to and infiltrates into works 19 by a Coulomb force based on the electric potential difference between the pair of electrode plates 13, 14. Further, since no discharge such as corona discharge is initiated between the electrode plates 13, 14 and works 19, the electrified smoke uniformly adheres to and infiltrates into the works 19. The invention according to claim 5 is a smoking apparatus according to claim 4, wherein an electrically insulative curtain (18) in reed screen shapes is attached to an inlet (11a) and an exit (11b) of the chamber (11), respectively. According to the smoking apparatus described in claim 5, the curtain 18 can prevent a worker from putting his/her hand into the chamber 11. The invention according to claim 6 is a smoking apparatus of claim 4, characterized inthat the distance between the electrode plate and work adjacent to the electrode plate is 20 mm to 100 mm. According to the smoking apparatus recited in claim 6 similarly to the invention according to claim 3, there can be more assuredly prevented initiation of discharge such as corona discharge or streamer discharge between the adjacent electrode plate and work. The invention according to claim 7, as shown in FIG. 3, is a smoking apparatus of claim 4, characterized in that the high voltage generating circuit 17 includes a single transformer 17a for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, that opposite ends of a secondary coil 17c of the transformer 17a are electrically connected to electrode plates 13, 14 respectively, and that one end of an intermediate tapping electric wire 47 having the other end electrically connected to the works 19 is electrically connected to an intermediate portion of the secondary coil 17c. According to the smoking apparatus recited in claim 7, one of the pair of electrode plates 13, 14 becomes plus when the other of the pair of electrode plates 13, 14 becomes minus. Thus, the electrified smoke between the electrode plates 13, 14 is immediately forced along the electric field generated between the electrode plates 13, 14 to thereby adhere onto and infiltrate into the works 19. The invention according to 8, as shown in FIG. 9, is a smoking apparatus of claim 4, characterized in that the high voltage generating circuit 127 includes first transformer121 and second transformer 122 identical to the first transformer for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, that one ends of secondary coils 121b, 122b of the first and second transformers 121, 122 are electrically connected to electrode plates , respectively, and that the other ends of the secondary coils 121b, 122b of the first and second transformers 121, 122 are electrically connected to works, respectively, via common electric wire 123. According to the smoking apparatus recited in claim 8 similarly to claim 7, the electrified smoke is immediately forced to adhere onto and infiltrate into the works. The invention according to claim 9, as shown in FIG. 3 or in FIG. 9, is a smoking apparatus of claim 7 or 8, characterized in that the intermediate tapping electric wire 47 or the common electric wire 123 is provided with a diode 52a, 53a for rectifying the electric current flowing through the intermediate tapping electric wire 47 or the common electric wire 123. According to the smoking apparatus recited in claim 9, it becomes possible to give a desired plus or minus electric charge to the smoke. This ensures adherence and infiltration of the desired smoke onto and into works, to thereby enable manufacture of a smoked food having a desired taste. The invention according to claim 10, as shown in FIGS. 1 and 4, is a smoking apparatus of claim 4, characterized in that the smoke generating means 17 includes: a hopper 22 for storing a smoking material 21, a screw conveyor 23 for transporting the smoking material 21, a burn heater 24 for incompletely burning the smoking material 21 transported by the screw conveyor 23, to thereby generate smoke, and a smoke inlet 26a for introducing the smoke into the chamber 11. According to the smoking apparatus recited in claim 10, simple supply of the smoking material 21 into the hopper 22 enables automatic generation of the smoke and automatic introduction of the smoke into the chamber 11. Further, since the flow rate of the smoke can be extremely reduced, the efficiency of adherence and infiltration of the smoke onto and into works 19 can be improved. The invention according to claim 11, as shown in FIGS. 4 and 5, is a smoking apparatus of claim 10, further comprising: an ionizing electrode wire 39 provided across a smoke inlet 26a for passing the smoke therethrough, the ionizing electrode wire 39 being applied with a DC voltage or AC voltage of 6 kV to 10 kV. According to the smoking apparatus recited in claim 11, there is initiated streamer discharge between the ionizing electrode wire 39 and the smoke to thereby previously electrify the smoke. Here, streamer discharge does mean discharge in which electrons accelerated by an electric field collide with gaseous molecules so as to successively ionize the gaseous molecules into a plasma state, to thereby convert a gas into a conductive matter. Note, during progression of the streamer discharge, electrons are increased in an avalanche manner, and there are observed plasma columns called streamers which comprise electrons and positive ions and are accompanied with light generation. The invention according to claim 12 is a smoking apparatus of claim 4, further comprising: smoke circulating means for circulating the smoke introduced into the chamber, wherein the smoke circulating means comprises: a circulation duct having opposite ends communicated to an upper part and a lower part of the chamber respectively, and a fan disposed within the circulation duct so as to draw the smoke at the upper level within the chamber into the upper end of the circulation duct and to discharge the smoke from the lower end of the circulation duct into the chamber. According to the smoking apparatus recited in claim 12, operation of the fan causes the smoke at the upper level within the chamber to be drawn into the upper end of the circulation duct and then to be discharged into the chamber from the lower end of the circulation duct. This enables circulation of the smoke introduced into the chamber, to thereby allow utilization of the smoke without wastefulness. The invention according to claim 13, as shown in FIG. 3, is a smoking apparatus of claim 4, characterized in that condiments are added into a liquid 57c within a tank 57b of a humidifier 57 for keeping the humidity within the chamber 11 constant. According to the smoking apparatus recited in claim 13, operation of the humidifier 57 causes the condiments to be introduced into the chamber 11 together with the liquid 57c atomized by the humidifier 57, to thereby adhere onto and infiltrate into works 19. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view taken along a line A-A of FIG. 2 showing a smoking apparatus according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view taken along a line B-B of FIG. 1; FIG. 3 is an electrical diagram of the apparatus; FIG. 4 is a longitudinal cross-sectional view showing smoke generating means; FIG. 5 is a cross-sectional view taken along a line C-C of FIG. 4; FIG. 6 is a graph showing transitions of voltages applied between a pair of electrode plates when a changeover switch of an intermediate-tap oriented electric wire of a high voltage generating circuit is turned to a first switching contact; FIG. 7 is a graph showing transitions of voltages applied between the pair of electrode plates when the changeover switch of the intermediate-tap oriented electric wire of the high voltage generating circuit is turned to a second switching contact; FIG. 8 is a graph showing transitions of voltages applied between the pair of electrode plates when the changeover switch of the intermediate-tap oriented electric wire of the high voltage generating circuit is turned to a third switching contact; FIG. 9 is a view showing a high voltage generating circuit according to a second embodiment of the present invention; FIG. 10 is a cross-sectional view of a constitution showing smoke generating means according to a third embodiment of the present invention; FIG. 11 is a cross-sectional view taken along a line E-E of FIG. 10; BEST MODE FOR CARRYING OUT THE INVENTION There will be firstly detailed first embodiment of the present invention, with reference to the accompanying drawings. As shown in FIGS. 1 through 3, reference numeral 10 designates a smoking apparatus comprising: a chamber 11 formed with an inlet 11a and an exit 11b at opposite ends of the chamber 11; transporting means 12 moved into the chamber 11 from the inlet 11a toward the exit 11b; a pair of electrode plates 13, 14 disposed along a longitudinal direction of the transporting means 12 within the chamber 11; smoke generating means 16 for generating smoke and introducing it into the chamber 11; and a high voltage generating circuit 17 for applying a predetermined DC voltage or AC voltage between the pair of electrode plates 13, 14. The chamber 11 is formed into a tumbled rectangular column (FIG. 2), and the inlet 11a and exit 11b of the chamber 11 are attached with electrically insulative curtains 18 in reed screen shapes, respectively, to prevent a worker from putting his/her hand into the chamber 11 (FIG. 1). The transporting means 12 is a chain conveyor in this embodiment, and includes: a driving sprocket 12a rotatably mounted at an upper position of the exit 11b side of the chamber 11; a driven sprocket 12b rotatably mounted at an upper position of the inlet 11a side of the chamber 11; and an endless chain 12c wound around these sprockets 12a, 12b (FIGS. 1 and 2). The driving sprocket 12a is rotated by a driving motor 12d. Projected at predetermined intervals from an outer periphery of the chain 12c is a plurality of hooks 12e adapted to suspend a plurality of works 19, respectively, such as farm products, marine products, livestock products and processed foods thereof. The pair of electrode plates 13, 14 are disposed within the chamber 11 at predetermined distances from the works 19 suspended from the hooks 12e, respectively so as to interpose the works 19 between the pair of electrode plates 13, 14. Namely, the pair of electrode plates 13, 14 are mounted onto opposite inner surfaces of the chamber 11 via insulators 11c, respectively. The electrode plates 13, 14 are formed into mesh, punching metal or flat plate shapes, such as of aluminum, aluminum alloy, stainless steel, or titanium. Further, the works 19 are electrically connected to the chain 12c via hooks 12e. Works 19 include: fish and shellfish such as salmon, trout, crab, herring, scallop and squid; meat such as beef, pork, chicken; avian egg such as hen egg, quail egg; vegetables such as radish, carrot, burdock, celery, udo (Aralia cordata); and processed foods such as sausage, ham, beef jerky, bacon, cheese. The time length required by a work 19 suspended from one hook 12e to reach the exit 11b from the inlet 11a varies depending on the sort of the work 19, and is suitably set at a predetermined time length between 5 minutes to 2 hours. Note, instead of the chain conveyor, it is possible to adopt a wire conveyor or roller conveyor as the transporting means 12, and even a grounded cage to be transported through the chamber 11 at a predetermined speed. The smoke generating means 16 is moved into the lower part of the chamber 11 from the inlet 11a side (FIG. 1). As shown in detail in FIGS. 4 and 5, this smoke generating means 16 includes: a hopper 22 for storing a mass of smoking material 21; a screw conveyor 23 for transporting the smoking material 21; a burn heater 24 for incompletely burning the smoking material 21 transported by the screw conveyor 23, to thereby generate smoke; and a smoke inlet 26a for introducing the smoke into the chamber 11. The smoking material 21 to be stored in the hopper 22 preferably includes: wood chips such as cherry tree, beech, oak; and orange peel, straw, black tea leaf, green tea leaf, herb, sake lees, miso, pinecone, coffee beans, and seed of pickled plum. Further, the smoke consists of a solid substance, a liquid substance and a gaseous substance (volatile substance), including: phenols such as guaiacol, eugenol; alcohols such as methyl alcohol and ethyl alcohol; carbonyl compounds such as formaldehyde and acetaldehyde; organic substances such as formic acid and acetic acid; and carbohydrates such as benzene and toluene. The screw conveyor 23 is housed within a rectangular column body 26, and comprises: a helical feeder 23c including a rotary shaft 23a and a vane 23b spirally fixed on the outer periphery of the rotary shaft 23a; a guiding cylinder 23d into which the helical feeder 23c is inserted; and an electric motor 23e for rotatively driving the helical feeder 23c. The burn heater 24 is coupled to the distal end of the guiding cylinder 23d via insulating spacer 27 such that the guiding cylinder 23d and the burn heater 24 are horizontally placed on a base 28 via supports 29, the base 28 being fixed within the rectangular column body 26. The burn heater 24 is formed in a cylindrical shape having inner and outer diameters identical with those of the guiding cylinder 23d, respectively, and is formed with an opening part 24a throughout an area from the center to the distal end of the upper surface of the burn heater 24. The electric motor 23e is mounted to an upper surface of the proximal end of the base 28 via first bracket 31. The helical feeder 23c is rotatably inserted into the guiding cylinder 23d and burn heater 24. The helical feeder 23c has its near proximal end portion rotatably held by the proximal end of the guiding cylinder 23d via bearing 33, and its distal end rotatably held by another bearing 33 and a second bracket 32 mounted on the upper surface of the distal end of the base 28. The proximal end of the helical feeder 23c is coupled to an output shaft 23f of the electric motor 23e via coupling 34, while the lower end of the hopper 22 is coupled to an upper surface of the guiding cylinder 23d near the proximal end of this cylinder 23d. The smoke inlet 26a is formed in an upper surface at the distal end of the rectangular column body 26. In FIG. 4, reference numeral 36 designates a fan insertedly mounted at the proximal end of the rectangular column body 26 so as to feed the smoke from the smoke inlet 26a into the chamber 11. Reference numeral 37 designates an ash tray placed on the upper surface of the base 28 near its distal end so as to receive ashes 37a left after combustion of the smoking material 21. Reference numeral 38 designates a temperature sensor provided at the opening part 24a of the burn heater 24 so as to detect the temperature of air (containing the smoke) passing through the smoke inlet 26a. Provided across the smoke inlet 26a is an ionizing electrode wire 39. This electrode wire 39 is preferably formed of a tungsten wire, and has opposite ends connected with pulling coil springs 39a, respectively, for providing the electrode wire 39 with a tensile force. Further, a pair of electrically conductive plates 26b, 26b are mounted at the opposite sides of the inner surface of the smoke inlet 26a, via insulating plates 26c, 26c, respectively (FIG. 5). There is applied a DC voltage or AC voltage of 5 kV to 15 kV, and preferably 6 kV to 10 kV, between the electrode wire 39 and the electrically conductive plates 26b, 26b. To initiate streamer discharge between the electrode wire 39 and electrically conductive plates 26b, 26b, the distance between the electrode wire 39 and each electrically conductive plate 26b is set at 8 to 15 mm, and preferably on the order of 10 mm. The electrode wire 39 loosely carries thereon an insulating ring 39b such as glass bead or glass sleeve. Upon flying out of electrons from the electrode wire 39, the electrode wire 39 may resonate as a reaction thereto to thereby vibrate, and the insulating ring 39b is provided to restrict such resonance. As shown in detail in FIG. 3, the high voltage generating circuit 17 includes a single transformer 17a for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV. This transformer 17a has its secondary coil 17b connected to a commercial frequency power source 46 of AC 100V or AC 200 V, via first controller 41. The first controller 41 is constituted of a voltage regulator (SLIDAC), for example, for adjusting the commercial frequency voltage. Adjustment of this first controller 41 allows to boost the voltage of a secondary coil 17c of the transformer 17a up to a predetermined voltage within a range of 7 kV to 15 kV. Both ends of the secondary coil 17c of the transformer 17a are electrically connected to the pair of electrode plates 13, 14, respectively, while the secondary coil 17c and works 19 are electrically connected via intermediate tapping electric wire 47. This intermediate tapping electric wire 47 has one end electrically connected to works 19 via chain 12c and hooks 12e, and the other end electrically connected to an intermediate portion of the secondary coil 17c. Note, works 19 are grounded via hook 12e and chain 12c. The intermediate tapping electric wire 47 is provided with a changeover switch 48. This switch 48 includes: a single common contact 48a; first through third changeover contacts 48b, 48c, 48d; and a movable piece 48e having one end connected to the common contact 48a and other end switchably connected to one of the first through third changeover contacts 48b, 48c, 48d. The first through third changeover contacts 48b, 48c, 48d are connected to the intermediate portion of the secondary coil 17c via first through third branching electric wires 51, 52, 53. The second branching electric wire 52 is provided with a first diode 52a for allowing an electric current from the second changeover contact 48c toward the secondary coil 17c and inhibiting an opposite electric current, while the third branching electric wire 53 is provided with a second diode 53a for inhibiting an electric current from the third changeover contact 48d toward the secondary coil and allowing an opposite electric current. Applied between the pair of electrode plates 13, 14 is a DC voltage or AC voltage of 7 kV to 15 kV, and preferably 8 kV to 12 kV, identically with that of the secondary coil 17c of the transformer 17a. The distances between the electrode plates 13, 14 and works 19 adjacent to the electrode plate are preferably set at 20 mm to 100 mm, and more preferably 25 to 80 mm, respectively. Why the voltage to be applied between the pair of electrode plates 13, 14 is limited to a range of 7 kV to 15 kV is that voltages below 7 kV lead to insufficient electrification of the smoke and voltages exceeding 15 kV lead to initiation of discharge. Why the distances between the electrode plates 13, 14 and works 19 are set at 20 mm to 100 mm is that distances shorter than 20 mm leads to initiation of discharge and distances exceeding 100 mm lead to insufficient electrification of the smoke. The voltage to be applied between the pair of electrode plates 13, 14 and the distances between the electrode plates 13, 14 and works 19 have a proportional relationship assuming that the electric field to be generated between the pair of electrode plates 13, 14 is constant. These voltage and distances are appropriately set at optimum values within the aforementioned ranges, respectively. Provided within the chamber 11 are a temperature sensor 54 (FIG. 3) for detecting the temperature within the chamber 11, and a thermostatic heater 56 (FIGS. 1 through 3) for adjusting the temperature within the chamber 11. The thermostatic heater 56 is constituted to be controlled by a second controller 42 (FIG. 3), based on the detection output from the temperature sensor 54. Further, the burn heater 24 of the smoke generating means 16 is controlled by a third controller 43, while the rotational speed of the fan 36 is controlled by a fourth controller 44. The chamber 11 is further communicated with a humidifier 57 for keeping the humidity within the chamber 11 constant, via duct (not shown). The humidifier 57 is an ultrasonic humidifier in this embodiment, and includes an oscillation circuit 57a electrically connected to the commercial frequency power source 46, and an ultrasonic vibrating element 57d which is electrically connected to the oscillation circuit 57a and which is provided at a bottom of a tank 57b. The ultrasonic vibrating element 57d is preferably constituted to be vibrated at a frequency of 28 kHz to 50 kHz, by the oscillation circuit 57a. The tank 57b contains a liquid 57c (such as water) added with condiments. The condiments preferably include miso, soy sauce, salt, sugar, garlic, sweet sake, wine, or mixtures thereof. In FIG. 1, reference numeral 58 designates a controlling box. In FIGS. 1 and 2, reference numeral 11d designates an exhaust duct for exhausting, together with air, the smoke introduced into the chamber 11, and reference numeral 11e designates a mesh-like screen provided at the lower part of the chamber so as to catch foreign matters such as fallen from works 19. In FIG. 3, reference numeral 59 designates a main switch, and reference numeral 60 designates a high-voltage-generating-circuit oriented switch. In this embodiment, the smoke introduced into the chamber is to be exhausted into the atmosphere from the exhaust duct. However, it is possible to connect one end of a circulation duct to an intermediate portion of the exhaust duct, to connect the other end of the circulation duct to the lower part of the chamber, and to provide a fan within the circulation duct. In this situation, operation of the fan causes the smoke within the chamber to be again introduced into the lower part of the chamber through the circulation duct, thereby utilizing the smoke without wastefulness. Further, works are to be suspended from the transporting means, in the above embodiment. However, works may be pinched by the transporting means or disposed on the transporting means, insofar as works can be transported by the transporting means at predetermined intervals. There will be now described the operation of the thus constituted smoking apparatus. Firstly, the smoking material 21 is stored within the hopper 22 and the smoke generating means 16 is operated, to thereby apply a predetermined DC voltage or AC voltage to the ionizing electrode wire 39. As the helical feeder 23c is rotatively driven by the electric motor 23e, the smoking material 21 within the hopper 22 is transported through the guiding cylinder 23d up to the burn heater 24, and incompletely burnt by the burn heater 24 to thereby generate smoke. This smoke goes up through the opening part 24a of the burn heater 24, and is then carried by the air stream caused by the fan 36 from the smoke inlet 26a into the chamber 11. In this way, simple supply of the smoking material 21 into the hopper 22 allows automatic generation of the smoke by the smoke generating means 16, and automatic introduction of the smoke into the chamber 11. Further, controlling the rotational speed of the fan 36 by the fourth controller 44 allows an extremely lower flow rate of the smoke. This allows an extremely small flow of the smoke within the chamber 11, thereby allowing an improvement in an efficiency of adherence and infiltration of the smoke to and into works 19. When the smoke passes through the smoke inlet 26a, there has been started the streamer discharge between the ionizing electrode wire 39 and the electrically conductive plates 26b, 26b. Thus, there is also initiated streamer discharge between the ionizing electrode wire 39 or electrically conductive plates 26b and the smoke. This allows electrification of a large amount of smoke, before introduction thereof into the chamber 11. Next, the transporting means 12 is operated when the smoke has spread throughout the interior of the chamber 11, so as to apply a predetermined AC voltage between the pair of electrode plates 13, 14 by the high voltage generating circuit 17 under a state where the changeover switch 48 is switched to the first changeover contact 48b. This causes a predetermined electric field incapable of initiating discharge between the pair of electrode plates 13, 14, so that the smoke which has not been electrified is also electrified, thereby resulting in electrification of substantially the whole of the smoke within the chamber 11. Under this condition, those works 19 hung on hooks 12e positioned outside the inlet 11a of the chamber 11 are brought into the chamber 11 via inlet 11a up to between the pair of electrode plates 13, 14, so that the electrified smoke is adhered to and infiltrated into works 19 by a Coulomb force based on the electric potential difference between the pair of electrode plates 13, 14. The voltages to be applied to the pair of electrode plates 13, 14, respectively, vary in the manner shown in FIG. 6. Namely, viewed from the center point comprising the intermediate tapping electric wire 47, one of the pair of electrode plates 13, 14 becomes plus when the other becomes minus, one of the pair of electrode plates 13, 14 becomes minus when the other becomes plus, and the pair of electrode plates 13, 14 alternately become plus and minus. As a result, the positively electrified smoke is immediately forced along electric force lines between electrode plates 13, 14, and the negatively electrified smoke is immediately forced in the direction opposite to the electric force lines, to thereby adhere onto and infiltrate into the works 19, so that the electrified smoke can be effectively adhered to and infiltrated into the works 19. The voltage to be applied between the pair of electrode plates 13, 14 is low as compared with that in the conventional electrical smoking method, so that no discharge is initiated between these electrode plates 13, 14. This allows an extremely low electric current to be flowed between the electrode plates 13, 14, and only a slight amount of electric power consumption. Further, those ingredients such as phenols, alcohols and acetic acid included in the smoke adhered to and infiltrated into the works 19 will restrict development, growth and increase of bacteria within works 19, and bacteria within works 19 will perish by placing works 19 within an electrostatic field as described above. Namely, the smoking apparatus of the present invention also has an antibacterial and sterilizing effect. Note, the smoke also includes ingredients such as: tar which adheres to and infiltrates into works 19 to thereby color works 19 in a particular color; and aromatics for providing works 19 with a specific aroma. Further, application of a high frequency voltage to the ultrasonic vibrating element 57d from the oscillation circuit 57a cause vibration of the ultrasonic vibrating element 57d at an extremely high frequency. Thus, addition of condiments to the liquid 57c within the tank 57b of the humidifier 57 results in atomization of the liquid 57c together with the condiments upon transmission of the vibration to the liquid 57c. As a result, condiments atomized together with the liquid 57c are introduced into the chamber 11 through the duct (not shown), electrified between the pair of electrode plates 13, 14, and then adhered to and infiltrated into works 19, to thereby deepen the taste of works 19. Meanwhile, when the movable piece 48e of the changeover switch 48 is switched to the second changeover contact 48c, the voltages to be applied to the pair of electrode plates 13, 14 respectively, vary in the manner shown in FIG. 7. Namely, viewed from the center point comprising the intermediate tapping electric wire 47, one of the pair of electrode plates 13, 14 becomes plus when the other becomes neutral, one of the pair of electrode plates 13, 14 becomes neutral when the other becomes plus, and the pair of electrode plates 13, 14 alternately become plus. As a result, it becomes possible to provide the smoke with a negative charge between the pair of electrode plates 13, 14 so as to assuredly render the desired smoke to adhere onto and infiltrate into works 19, to thereby enable manufacture of a smoked food having a desired taste. Further, when the movable piece 48e of the changeover switch 48 is switched to the third changeover contact 48d, the voltages to be applied to the pair of electrode plates 13, 14 respectively, vary in the manner shown in FIG. 8. Namely, viewed from the center point comprising the intermediate tapping electric wire 47, one of the pair of electrode plates 13, 14 becomes minus when the other becomes neutral, one of the pair of electrode plates 13, 14 becomes neutral when the other becomes minus, and the pair of electrode'plates 13, 14 alternately become minus. As a result, it becomes possible to provide the smoke with a positive charge between the pair of electrode plates 13, 14 so as to assuredly render the desired smoke to adhere onto and infiltrate into works 19, to thereby enable manufacture of a smoked food having a desired taste. FIG. 9 shows a second embodiment of the present invention. Like reference numerals as used in FIG. 3 are used to denote identical elements in FIG. 9. In this embodiment, there is provided a high voltage generating circuit 127 including first transformer121 and second transformer 122 identical to the first transformer for boosting the commercial frequency voltage up to an AC voltage at 3.5 kV to 7.5 kV, and preferably 4 kV to 6 kV. One ends of the secondary coils 121b, 122b of the first and second transformers 121, 122 are electrically connected to electrode plates (not shown), respectively, and the other ends of the secondary coils 121b, 122b of the first and second transformers 121, 122 are electrically connected to works (not shown) via common electric wire 123. Similarly to the first embodiment, the first through third branching electric wires 51, 52, 53 are connected to the common electric wire 123, and the second and third branching electric wire 52, 53 are provided with first and second diodes 52a, 53a. In FIG. 9, reference numerals 121a, 122a designate primary coils of the first and second transformers 121, 122, respectively. The remaining constitution is identical with that of the first embodiment. In the thus constituted smoking apparatus, the electric potential difference between one electrode plate and the other electrode plate becomes larger than that in the first embodiment, assuming that the voltage of the commercial frequency power source is kept constant. Thus, the electrified smoke rapidly adheres onto works. Redundant explanation shall be omitted concerning the thus constituted smoking apparatus, since its operation is substantially identical with that of the first embodiment. FIGS. 10 and 11 show a third embodiment of the present invention. In this embodiment, smoke generating means 196 includes: vertically extending two cylindrical bodies 191, 191; smoke generating cylinders 192, 192 which are formed by spirally winding rods at a predetermined spacing therebetween and housed within the cylindrical bodies 191, 191, respectively; ash trays 193 provided below the cylindrical bodies 191, 191, respectively; a guiding cylinder 194 disposed adjacent to the cylindrical body 191 and communicated with the lower end of the cylindrical bodies 191, 191 to thereby guide the smoke therefrom; a smoke outflow pipe 197 communicated to the side surface of the guiding cylinder 194; and a blower (not shown) provided in the smoke outflow pipe 197. The two cylindrical bodies 191, 191 are formed integrally with the guiding cylinder 194. The guiding cylinder 194 is constituted such that the smoke is guided through a path in an inverted "U" shape provided by an upstanding partition plate 198 within the guiding cylinder 194. Communicated to the upper surface of the guiding cylinder 194 is an air introducing pipe 201, via switching damper 199. The switching damper 199 is switched to communicate the air introducing pipe 201 to one of the cylindrical bodies 191, 191. In FIG. 10, reference numeral 202 designates a flow rate adjusting damper for adjusting the air amount to be introduced, and reference numeral 203 designates a wire mesh for preventing passage of an unburnt smoking material and for allowing passage of the ash of the burnt smoking material. In the thus constituted smoking apparatus, when the blower is operated in a state where the smoking material is stored within the cylindrical body 191 inserted with the smoke generating cylinder 192, air is introduced through the air introducing pipe 201 into the cylindrical body 191, flowed down in the cylindrical body 191 and then through the guiding cylinder 194, and thereafter blown out of the smoke outflow pipe 197. Firing the upper end of the smoking material in this state leads to incomplete combustion of the smoking material to cause a smoke, and this smoke is carried by the air stream and blown out of the smoke outflow pipe 197 into the chamber (not shown). According to the present invention as described above, grounded works are transported by the transporting means at a predetermined speed into the chamber into which the smoke is introduced, and the voltage of 7 kV to 15 kV is applied between the pair of electrode plates arranged to interpose therebetween works along the transporting means within the chamber so as not to start discharge. Thus, there is generated a predetermined electric field incapable of initiating discharge between the pair of electrode plates to thereby electrify the smoke, and the thus electrified smoke adheres to and infiltrates into works by a Coulomb force based on the electric potential difference between the pair of electrode plates. This results in a lower voltage to be applied between the pair of electrode plates and in a smaller amount of an electric current, to thereby reduce the electric power consumption. Further, because discharge such as corona discharge is not initiated between the electrode plates and works, the electrified smoke uniformly adheres to and infiltrates into works. By setting the distance between the electrode plate and work adjacent to the electrode plate at 20 mm to 100 mm, there can be more assuredly prevented initiation of discharge such as corona discharge or streamer discharge between the adjacent electrode plate and work. Further, by inserting the transporting means into the chamber formed with the inlet and outlet at opposite ends of the chamber, by transporting the works spaced at predetermined intervals by the transporting means, by providing the pair of electrode plates along the longitudinal direction of the transporting means so as to interpose works between the electrode plates, by generating the smoke and introducing it into the chamber by the smoke generating means, and by grounding works and applying a voltage of 7 kV to 15 kV between the pair of electrode plates by the high voltage generating circuit so as not to start discharge, there is generated an electric field incapable of initiating discharge between the pair of electrode plates to thereby electrify the smoke, and the thus electrified smoke adheres to and infiltrates into the works by a Coulomb force based on the electric potential difference between the pair of electrode plates, similarly to the above. This results in a lower voltage to be applied between the pair of electrode plates and in a smaller amount of an electric current, to thereby reduce the electric power consumption and to thereby downsize the whole apparatus. Further, because discharge such as corona discharge is not initiated between the electrode plates and works, the electrified smoke uniformly adheres to and infiltrates into works. When the high voltage generating circuit has a single transformer for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, when both ends of this transformer are electrically connected to electrode plates, and when one end of the intermediate tapping electric wire is electrically connected to work and the other end of said intermediate tapping electronic wire is electrically connected to an intermediate portion of the secondary coil, one of the pair of electrode plates becomes plus when the other becomes minus so that the electrified smoke between the electrode plates is immediately forced along the electric field generated between the electrode plates to thereby adhere onto and infiltrate into. the works. This allows efficient adherence and infiltration of the electrified smoke onto and into works. When the high voltage generating circuit has first transformer and second transformer identical to the first transformer for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, when one ends of the transformers are electrically connected to electrode plates, respectively, and when the other ends of the secondary coils of the first and second transformers are electrically connected to the works via common electric wire, the electrified smoke immediately adheres to and infiltrates into works. This allows efficient adherence and infiltration of the electrified smoke onto and into works. Further, by providing the intermediate tapping electric wire or the common electric wire with diodes for rectifying the electric current flowing through the pertinent electric wire, it becomes possible to give a desired plus or minus electric charge to the smoke. This ensures adherence and infiltration of the desired smoke onto and into works, to thereby enable manufacture of a smoked food having a desired taste. By storing the smoking material in the hopper of the smoke generating means, by transporting this smoking material by a screw conveyor, and by incompletely burning the thus transported smoking material by the burn heater to thereby generate the smoke and introduce it into the chamber, simple supply of the smoking material into the hopper enables automatic generation of the smoke and automatic introduction of the smoke into the chamber. Further, since the flow rate of the smoke can be extremely reduced, the efficiency of adherence and infiltration of the smoke onto and into works can be improved. By providing the ionizing electrode wire across the smoke inlet, and by applying a voltage of 6 kV to 10 kV to the ionizing electrode wire, there is initiated streamer discharge between the ionizing electrode wire and the smoke to thereby previously electrify the smoke. As a result, it becomes possible to adhere and infiltrate the smoke onto and into the work more rapidly. Further, the streamer discharge requires an electric current less than that for corona discharge, so that the increase in the electric power consumption is only a little. Further, by communicating opposite ends of the circulation duct of the smoke circulating means to the upper part and lower part of the chamber, respectively, and by providing the fan within the circulation duct, operation of the fan causes the smoke at the upper level within the chamber to be drawn into the upper end of the circulation duct and then to be discharged into the chamber from the lower end of the circulation duct. This enables circulation of the smoke introduced into the chamber, to thereby allow utilization of the smoke without wastefulness. By adding condiments into the liquid within the tank of the humidifier for keeping the humidity within the chamber constant, operation of the humidifier causes the condiments to be introduced into the chamber together with the liquid atomized by the humidifier, to thereby adhere onto and infiltrate into works. As a result, works are finished into smoked foods having deepened tastes. INDUSTRIAL APPLICABILITY The smoking method and apparatus of the present invention renders the smoke to adhere onto and infiltrate into farm products, marine products and livestock products or processed foods thereof, making use of a Coulomb force of the aforementioned farm products and the like and the smoke electrified in the electric field when the smoke is to be adhered to and infiltrated into the aforementioned farm products and the like. This enables: uniform adherence and infiltration of the smoke onto and into works such as the aforementioned farm products and the like; an improved quality of smoked foods; and utilization of the smoke without wastefulness.

Claims: A smoking method comprising the steps of: transporting grounded works (19) at a predetermined speed into a chamber (11), into which smoke is introduced, by transporting means (12), said works (19) comprising farm products, marine products and livestock products or processed foods thereof, and applying a DC voltage or AC voltage of 7 kV to 15 kV between a pair of electrode plates (13, 14) disposed along said transporting means (12) within said chamber (11) so as to interpose the work (19) between said pair of electrode plates (13, 14), so as not to start discharge. A smoking method according to claim 1, wherein an electrically insulative curtain (18) in reed screen shapes is attached to an inlet (11a) and an exit (11b) of the chamber (11), respectively. A smoking method of claim 1, wherein the distance between the electrode plate and the work adjacent to the electrode plate is 20 mm to 100 mm. A smoking apparatus comprising: a chamber (11) having opposite ends thereof formed with an inlet (a) and an exit (11b), respectively, transporting means (12) moved into said chamber (11) from said inlet (a) toward said exit (11b), and for transporting a plurality of works (19) spaced at predetermined intervals, the works (19) comprising farm products, marine products and livestock products or processed foods thereof, a pair of electrode plates (13, 14) disposed within said chamber (11) at predetermined distances from the works (19), respectively, along the longitudinal direction of said transporting means (12) so as to interpose the works (19) between said pair of electrode plates (13, 14), smoke generating means (16, 196) for generating smoke to be adhered to and infiltrated into the works (19), and for introducing the smoke into said chamber (11), and a high voltage generating circuit (17, 127, 147, 167) for applying a DC voltage or AC voltage of 7 kV to 15 kV between said pair of electrode plates (13, 14) so as not to start discharge, and to ground the works (19). A smoking apparatus according to claim 4, wherein an electrically insulative curtain (18) in reed screen shapes is attached to an inlet (11a) and an exit (11b) of the chamber (11), respectively. A smoking apparatus of claim 4 , wherein the distance between the electrode plate and the work adjacent to the electrode plate is 20 mm to 100 mm. A smoking apparatus of claim 4, wherein said high voltage generating circuit (17) includes a single transformer (17a) for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, wherein opposite ends of a secondary coil (17c) of said transformer (17a) are electrically connected to electrode plates (13, 14), respectively, and wherein one end of an intermediate tapping electric wire (47) is electrically connected to the works (19) and the other end of said intermediate tapping electric wire (47) is electrically connected to an intermediate portion of said secondary coil (17c). A smoking apparatus of claim 4, wherein said high voltage generating circuit (127) includes a first transformer (121) and a second transformers (122) identical to the first transformer for boosting the commercial frequency voltage up to an AC voltage of 7 kV to 15 kV, wherein one ends of secondary coils (121b, 122b) of said first and second transformers (121, 122) are electrically connected to electrode plates , respectively, and wherein the other ends of said secondary coils (121b, 122b) of said first and second transformers (121, 122) are electrically connected to works , respectively, via common electric wire (123). A smoking apparatus of claim 7 or 8, wherein said intermediate tapping electric wire (47) or said common electric wire (123) is provided with a diode (52a, 53a) for rectifying the electric current flowing through said intermediate tapping electric wire (47) or said common electric wire (123). A smoking apparatus of claim 4, wherein said smoke generating means (16) includes a hopper (22) for storing a smoking material (21), a screw conveyor (23) for transporting the smoking material (21), a burn heater (24) for incompletely burning the smoking material (21) transported by said screw conveyor (23), to thereby generate smoke, and a smoke inlet (26a) for introducing the smoke into said chamber (11). A smoking apparatus of claim 10, further comprising: an ionizing electrode wire (39) provided across a smoke inlet (26a) for passing the smoke therethrough, said ionizing electrode wire (39) being applied with a DC voltage or AC voltage of 6 kV to 10 kV. A smoking apparatus of claim 4, further comprising: smoke circulating means for circulating the smoke introduced into said chamber, wherein said smoke circulating means comprises: a circulation duct having opposite ends communicated to an upper part and a lower part of said chamber, respectively, and a fan disposed within said circulation duct so as to draw the smoke at the upper level within said chamber into the upper end of said circulation duct and to discharge the smoke from the lower end of said circulation duct into said chamber. A smoking apparatus of claim 4 , wherein condiments are added into a liquid (57c) within a tank (57b) of a humidifier (57) for keeping the humidity within said chamber (11) constant.

Inventors: HIGUCHI MASAO, HOSHINO HIROSHI, MARUYAMA TOSHIHIKO, MIYAMORI MAMORU, SAITO HIROSHI, HIGUCHI, MASAO, HOSHINO, HIROSHI, MARUYAMA, TOSHIHIKO, MIYAMORI, MAMORU, SAITO, HIROSHI
Applicants: JAPAN SCIENCE & TECH CORP, UNIREX CO LTD, JAPAN SCIENCE AND TECHNOLOGY CORPORATION, UNIREX CO., LTD
Application year: 1999
Main classification: A23L3
IPC codes: A23L3, A23B4