Steam Generator

Abstract

To make water, in which scale components are condensed, less likely to remain in a steam generation container when the water in the steam generation container is discharged from a drain outlet.SOLUTION: A steam generator 30 includes: a cylindrical steam generation container 31 in which a predetermined amount of water is stored and which has a delivery port 31c for sending steam to an upper end part and a drain outlet 31d for discharging water to a lower end part; and heating means 32 which heats water in the steam generation container 31 to generate steam. A spiral groove 31f whose spiral direction is set to a vertical direction is formed on an inner peripheral surface of the steam generation container 31 to form a spiral passage formed by a passage having a spiral form.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a steam generating device used in a cooking appliance such as a steam convection oven. [Background technology]

[0002] The following Patent Document 1 discloses a cooking device that cooks ingredients with hot air. This cooking device includes a cooking chamber that cooks ingredients, a heater that heats the inside of the cooking chamber, a convection fan that circulates air in the cooking chamber, a steam generator that supplies steam into the cooking chamber, and a control device that controls the operation of the heater, the convection fan, and the steam generator. The control device of this cooking device includes a cooking program for cooking ingredients, and when the cooking program is executed by the control device, the air in the cooking chamber is turned into hot air by the operation of the heater and the convection fan and circulates, and steam is supplied to the convecting hot air by the operation of the steam generator, and the ingredients stored in the cooking chamber are cooked by the hot air containing steam.

[0003] The steam generating device used in this cooking appliance comprises a steam generating vessel that stores a predetermined amount of water inside and has an outlet at its upper end for sending out steam and a drain at its lower end, a heating body that heats the water in the steam generating vessel, an induction heating coil that is wound around the outer periphery of the steam generating vessel and causes the heating body to heat, and a steam sending tube that sends the steam generated in the steam generating vessel to the cooking chamber. When a high-frequency current is supplied to the induction heating coil, the heating body in the steam generating vessel generates heat due to Joule heat generated by electrical resistance when eddy currents flow, and the water in the steam generating vessel is heated to generate steam. The steam generated in the steam generating vessel is sent into the cooking chamber by the steam sending tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-121803 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the steam generating device of Patent Document 1, when steam is generated from the steam generating container, the scale components contained in the water in the steam generating container are concentrated. For this reason, in this type of steam generating device, when a cooking program that supplies steam to a cooking device is completed, the water in the steam generating container is discharged from a drain outlet. However, when the water in the steam generating container is discharged from the drain outlet, water containing concentrated scale components may remain in the steam generating container as water droplets, and when steam is repeatedly generated in the steam generating container, scale may accumulate in the steam generating container. The present invention aims to make it difficult for water containing concentrated scale components to remain in the steam generating container when the water in the steam generating container is discharged from the drain outlet. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a steam generating device comprising a cylindrical steam generating vessel which stores a predetermined amount of water therein and has an outlet at its upper end for sending out steam and an outlet at its lower end for discharging water, and heating means which heats the water in the steam generating vessel to generate steam, wherein the steam generating vessel has an inner peripheral surface formed with a spiral flow path having a spiral progression direction in the vertical direction.

[0007] In the steam generator configured as described above, a spiral flow path is formed on the inner circumferential surface of the steam generating vessel, which is a spiral flow path with the spiral moving in the up and down direction. When water is discharged from the drain outlet at the lower end of the steam generating vessel, the water in the steam generating vessel swirls due to the spiral flow path formed on the inner circumferential surface and is discharged from the drain outlet with great force, so that water with concentrated scale components is less likely to remain in the steam generating vessel.

[0008] In the steam generator configured as described above, a water inlet for supplying water is formed at the bottom of the steam generating vessel, and it is preferable to arrange the water inlet so that the inflow direction is along the inner peripheral surface of the steam generating vessel. When this is done, the water flowing into the steam generating vessel from the water inlet flows along the inner peripheral surface of the steam generating vessel. In addition, the water flowing along the inner peripheral surface in the steam generating vessel rises along the spiral flow path and swirls inside the steam generating vessel, so that scale components that are beginning to adhere to the inside of the steam generating vessel can be washed away after drainage. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a front view of a cooking device using a steam generating device of the present invention. [Diagram 2] FIG. 2 is a perspective view of FIG. 1 with the door open. [Diagram 3] FIG. 2 is a longitudinal cross-sectional view of the center portion in the front-rear direction. [Figure 4] This is a cross-sectional view taken along line AA. [Diagram 5] FIG. 2 is a longitudinal cross-sectional view at the position where the steam generating device is disposed. [Figure 6] 4 is a partial enlarged cross-sectional view of a portion where an exhaust pipe protrudes from a top plate of a housing. FIG. [Figure 7] Cross-sectional view taken along line B-B. [Figure 8] FIG. 11 is a left side view showing the left side machine compartment with the left panel of the housing removed. [Figure 9] FIG. [Figure 10] CC cross-sectional view. [Figure 11] 2 is a plan view of the steam generating vessel, the water level detection tank with the lid removed, and the hot water inflow prevention member. FIG. [Figure 12] 1A is a side view of the hot water inflow prevention member, FIG. 1B is a plan view, FIG. 1C is a DD cross-sectional view, FIG. 1D is a perspective view from the shielding portion side, and FIG. 1E is a perspective view from the steam passage port side. [Figure 13]EE cross-sectional view (a) and EE cross-sectional view (b) when the drain valve motor is rotated from (a) so as to be positioned outside the left side machine room. [Figure 14] FIG. [Figure 15] FIG. 2 is a vertical cross-sectional view at a position where the intake damper device is disposed. [Figure 16] FIG. 2 is a block diagram of a control device. BEST MODE FOR CARRYING OUT THEINVENTION

[0010] A cooking device using one embodiment of the steam generating device of the present invention will be described below with reference to the attached drawings. The cooking device using the steam generating device of the present invention is called a steam convection oven, which cooks food by convection of hot air containing steam. As shown in FIG. 1, the cooking device 10 has machine chambers 12, 13 (hereinafter also referred to as the left machine chamber 12 and the lower machine chamber 13) on the left side and the lower part of the housing 11, and is provided with a cooking chamber 20 for cooking food in the part of the housing 11 excluding the machine chambers 12, 13. As shown in FIG. 2, an opening 20a for putting in and taking out food is provided on the front part of the cooking chamber 20, and a door 14 for opening and closing the opening 20a is provided.

[0011] As shown in FIG. 3, the cooking chamber 20 is for storing ingredients and cooking them. The cooking chamber 20 except for the left side is a food storage chamber 21 for storing ingredients, and the left side is a hot air generating chamber 22 for generating hot air to be sent to the food storage chamber 21. As shown in FIG. 4, a steam inlet 20b and an outside air inlet 20c are formed in the left side wall of the cooking chamber 20, and as shown in FIG. 5, a drain port 20d is formed in the bottom wall of the cooking chamber 20. A steam generator 30, which will be described later, is connected to the steam inlet 20b, and an air intake damper device 80, which will be described later, is connected to the outside air inlet 20c. The outside air inlet 20c is formed in a position (left side) hidden by the fan blades of a convection fan 26, which will be described later. The drain port 20d is connected to a drain tank 16 by a first drain pipe 15, and water in the cooking chamber 20 is drained into the drain tank 16 through the first drain pipe 15. A second drain pipe (not shown) is connected to the drain tank 16, and water in the cooking chamber 20 is drained into the drain tank 16 through the first drain pipe 15 and then drained outside the housing 11 through the second drain pipe.

[0012] As shown in Figs. 5 and 6, an exhaust pipe 17 is provided in the drain tank 16, and the exhaust pipe 17 protrudes upward from an opening formed in the top plate of the housing 11. Air in the cooking chamber 20 is discharged into the drain tank 16 through the first drain pipe 15, and the air discharged into the drain tank 16 is discharged to the upper side of the housing 11 through the exhaust pipe 17. A packing 18 is provided at the upper end of the exhaust pipe 17, and the packing 18 liquid-tightly seals the gap between the exhaust pipe 17 and the ceiling wall of the housing 11. The packing 18 is made of an elastically deformable rubber material, and has a thick circular ring shape that fits snugly against the outer circumferential surface of the exhaust pipe 17. An engagement groove 18a recessed inward is formed in the outer circumferential surface of the packing 18, and the periphery of the opening of the top plate of the housing 11 is sandwiched between the engagement groove 18a from above and below. A downwardly projecting protrusion (not shown) is formed around the entire periphery of the upper part of engagement groove 18a, and an upwardly projecting protrusion (not shown) is formed around the entire periphery of the lower part of engagement groove 18a. Since the edge of the opening in the top plate of housing 11 is sandwiched in engagement groove 18a of packing 18, water is less likely to flow into left side machine chamber 12 from between the opening in the top plate of housing 11 and exhaust pipe 17.

[0013] As shown in FIG. 3, a partition plate 23 is provided on the left side of the center of the cooking chamber 20 in the left-right direction, and the partition plate 23 separates the food storage chamber 21 and the hot air generating chamber 22 to allow ventilation. The partition plate 23 functions as a fan cover that covers the suction port side of the convection fan 26 arranged in the hot air generating chamber 22. As shown in FIG. 7, the partition plate 23 has a number of suction ports 23a, and the air in the food storage chamber 21 is sent to the hot air generating chamber 22 through the suction ports 23a. The partition plate 23 is also attached so that a space through which air can pass is formed between the ceiling wall, bottom wall, front wall, and rear wall of the cooking chamber 20. A ventilation passage 23b through which air passes is formed between the partition plate 23 and the ceiling wall, bottom wall, front wall, and rear wall of the cooking chamber 20, and the air in the hot air generating chamber 22 is sent to the food storage chamber 21 through the ventilation passage 23b.

[0014] As shown in Fig. 3, a pair of left and right support frames 24 that support multiple levels of trays called hotel pans are provided in the food storage chamber 21 of the cooking chamber 20. The support frames 24 in this embodiment can support three levels of shallow trays vertically and two levels of deep trays shown in Fig. 3 vertically. The left support frame 24 is fixed to the partition plate 23, and the right support frame 24 is fixed to the right wall of the cooking chamber 20.

[0015] As shown in Figures 3 and 4, a heater 25 and a convection fan 26 are provided in the hot air generating chamber 22 of the cooking chamber 20. The heater 25 heats the inside of the cooking chamber 20, and is wound in a substantially circular shape on the left side wall of the cooking chamber 20. The convection fan 26 causes convection of the air inside the cooking chamber 20, and is attached inside the heater 25 wound in a substantially circular shape on the left side wall of the cooking chamber 20. The convection fan 26 in this embodiment is a centrifugal fan made of a sirocco fan. A temperature sensor 27 is provided on the left side wall of the cooking chamber 20, and the temperature sensor 27 detects the temperature inside the cooking chamber 20.

[0016] When the convection fan 26 is operated, air from the food storage chamber 21 is sucked into the hot air generating chamber 22 through the suction port 23a of the partition plate 23, the sucked air is blown outward in the centrifugal direction in the hot air generating chamber 22, and the blown air passes through the top-bottom and front-rear ventilation paths 23b before being returned to the food storage chamber 21. When the convection fan 26 is operated together with the heater 25, the air sucked into the hot air generating chamber 22 from the food storage chamber 21 is blown against the heater 25 arranged outside the convection fan 26 and becomes high-temperature hot air, which is returned to the food storage chamber 21 through the top-bottom and front-rear ventilation paths 23b.

[0017] As shown in Figs. 5, 8 and 9, a steam generator 30 for supplying steam into the cooking chamber 20 is provided at the rear of the left machine chamber 12 of the housing 11, and the steam generator 30 is erected on the upper side of the drain tank 16 provided at the rear of the left machine chamber 12. The steam generator 30 of this embodiment heats water by induction heating to generate steam, and sends the generated steam to the cooking chamber 20 as a destination. As shown in Figs. 5 and 10, the steam generator 30 includes a steam generating vessel 31 that stores a predetermined amount of water therein and has an outlet 31c at the upper end for sending steam, a heating means 32 that heats the water in the steam generating vessel 31 to generate steam, and a steam sending section 40 that sends the steam generated at the upper part of the steam generating vessel 31 from the outlet 31c to the cooking chamber 20, which is a destination adjacent in the horizontal direction.

[0018] As shown in Fig. 5 and Fig. 10, the steam generating vessel 31 is generally cylindrical with openings at the top and bottom. The steam generating vessel 31 has a tapered portion 31a whose diameter becomes smaller as it goes downward, and a small diameter portion 31b below the tapered portion 31a, which has a smaller diameter than the other portions. The steam generating vessel 31 has an outlet 31c for sending out steam at the upper end, a drain outlet 31d for draining water at the lower end of the small diameter portion 31b, and a water supply port 31e for supplying water to the upper side of the tapered portion 31a. The water supply port 31e is connected to a water level detection tank 50 by a communication pipe 51 described later, and water sent from a water supply pipe 53 is supplied to the steam generating vessel 31 through the water level detection tank 50. As shown in Fig. 11, the inflow direction of water from the water supply port 31e is arranged along the inner circumferential surface of the steam generating vessel 31. 10, a helical flow path is formed on the inner circumferential surface of the steam generating vessel 31 by a helical groove 31f with the vertical direction as the spiral progression direction, which is a helical flow path. This helical flow path is formed by the helical groove 31f formed on the inner circumferential surface of the steam generating vessel 31, but is not limited to this, and the helical flow path may be formed by a helical ridge formed on the inner circumferential surface of the steam generating vessel 31.

[0019] As shown in Fig. 5 and Fig. 10, the heating means 32 heats the water in the steam generating vessel 31, and in this embodiment, heats the water in the steam generating vessel 31 by induction heating. The heating means 32 includes a heating body 33 using a magnetic member provided in the steam generating vessel 31, and an induction heating coil 34 wound around the outer periphery of the steam generating vessel 31 from the middle to the lower part in the vertical direction. The heating body 33 heats the water in the steam generating vessel 31 by Joule heat generated by electrical resistance when an eddy current flows due to the influence of a magnetic field generated when a high-frequency current is supplied to the induction heating coil 34. The heating body 33 includes a substantially annular holder 33a supported on the upper part of the steam generating vessel 31, and a plurality of heating rods 33b whose upper ends are fixed to the holder 33a.

[0020] As shown in Figures 9 and 10, brackets 35, 36 are provided at the middle and lower parts of the steam generating vessel 31 in the vertical direction, and the induction heating coil 34 is wound between the upper and lower brackets 35, 36. As shown in Figures 9 and 11, eight notches 35a, 36a are formed in the upper and lower brackets 35, 36 along the circumferential direction, and ferrite members 37 are provided in the notches 35a, 36a to block magnetic field lines leaking from the induction heating coil 34. The ferrite member 37 is substantially L-shaped with the top and bottom facing inverted, and the upper horizontal part and the part immediately below this are bonded to the notch 35a of the upper bracket 35 with a caulking agent, and the lower part is bonded to the notch 36a of the lower bracket 36 with a caulking agent.

[0021] As shown in Figs. 5, 9 and 10, a steam delivery section 40 is provided on the upper side of the steam generating vessel 31 to deliver steam to the cooking chamber 20 as a horizontally adjacent delivery destination. As shown in Fig. 5, the steam delivery section 40 includes a steam receiver 41 provided on the upper side of the steam generating vessel 31 and a delivery tube 42 that guides the steam received by the steam receiver 41 to the cooking chamber 20. The steam receiver 41 receives steam that is generated in the upper part of the steam generating vessel 31 and rises, and has a substantially cylindrical shape with the upper side closed and the lower side open. The steam receiver 41 includes a fitting section 41a that is fitted to the outer peripheral surface of the upper end of the steam generating vessel 31, a receiving section 41b formed above the fitting section 41a with a diameter smaller than that of the fitting section 41a, and a first inclined tube section 41c provided on the peripheral surface of the receiving section 41b on the cooking chamber 20 side. The first inclined tube section 41c is inclined upward toward the cooking chamber 20, which is the delivery destination of the steam. A delivery tube 42 is connected in communication with the inner circumferential surface of the tip of the first inclined tube portion 41c, and the delivery tube 42 is connected to a steam inlet 20b formed in the left wall of the cooking chamber 20.

[0022] As shown in Figure 5, the delivery tube 42 is integrally equipped with a second inclined tube section 42a that, like the first inclined tube section 41c, inclines upward toward the cooking chamber 20, which is the destination of the steam, and a horizontal tube section 42b that extends horizontally from the tip of the second inclined tube section 42a toward a steam inlet 20b formed on the left side wall of the cooking chamber 20.

[0023] As shown in Fig. 5, an annular recess 41d is formed on the inner peripheral surface of the tip of the first inclined tube portion 41c, and the second inclined tube portion 42a of the delivery tube 42 is fitted and fixed in the annular recess 41d. The annular recess 41d is formed with a depth equal to or less than the thickness of the second inclined tube portion 42a, and the inner peripheral surface of the second inclined tube portion 42a fitted in the annular recess 41d is formed smaller than the inner peripheral surface of the first inclined tube portion 41c. Hot water droplets and condensation adhering to the inner peripheral surface of the second inclined tube portion 42a flow down the first inclined tube portion 41c without remaining in the joint between the first inclined tube portion 41c and the second inclined tube portion 42a and return to the steam generating vessel 31.

[0024] 5 and 12, a hot water inflow prevention member 43 is provided on the upper part of the steam generating vessel 31 to prevent boiling hot water from being sent into the cooking chamber 20. The hot water inflow prevention member 43 includes an annular frame portion 44 provided at the steam outlet 31c at the upper end of the steam generating vessel 31, a shielding portion 45 provided inside the frame portion 44 on the cooking chamber 20 side to which the steam is sent, and a steam passage port 46 formed inside the frame portion 44 on the horizontal opposite side to the cooking chamber 20 side to which the steam is sent, to allow steam to pass through.

[0025] The frame 44 of the hot water inflow prevention member 43 is fitted into the upper end of the inner circumferential surface of the steam generating vessel 31, and the lower end of the frame 44 is engaged with a step 31g formed on the inner circumferential surface at the upper end of the steam generating vessel 31. By engaging the lower end of the frame 44 with the step 31g at the upper end of the steam generating vessel 31, the hot water inflow prevention member 43 is positioned in the height direction at the upper part of the steam generating vessel 31.

[0026] 5, 11 and 12, the shielding portion 45 covers approximately half of the inside of the frame portion 44 on the cooking chamber 20 side, which is the destination of steam, and has a shape obtained by cutting approximately half in the horizontal direction a dome shape that bulges upward in an approximately hemispherical shape toward the horizontal center of the frame portion 44 (the delivery port 31c of the steam generating vessel 31). The shielding portion 45 covers the diagonally upper side of the steam passage port 46 on the cooking chamber 20 side, so that it is possible to capture many water droplets that boil up in the upper part of the steam generating vessel 31 and flow toward the cooking chamber 20 side.

[0027] Steam passage port 46 is for sending steam generated in the upper part of steam generating container 31 into upper steam receiver 41 in order to send the steam to the destination, cooking chamber 20. Steam passage port 46 not only has an opening in approximately half of the inside of frame portion 44 in a plan view, but also opens at a height portion that bulges above shielding portion 45 at the horizontal center of the inside of frame portion 44. Therefore, steam passage port 46 has a larger opening area than when approximately half of the inside of frame portion 44 is blocked with a flat plate.

[0028] 11 and 12, three positioning projections 44a-44c are formed to project downward at the lower end of the frame 44, and positioning recesses 31h-31j are formed to recess downward at positions facing the positioning projections 44a-44c on the upper surface of the step 31g of the steam generating vessel 31. The positioning projections 44a-44c of the frame 44 and the positioning recesses 31h-31j at the upper end of the steam generating vessel 31 are intended to position the shielding portion 45 of the hot water inflow prevention member 43 on the side of the cooking chamber 20, which is the destination of the steam.

[0029] The positioning recesses 31h-31j are formed at positions spaced apart from one another in the circumferential direction of the steam generating vessel 31, and the circumferential length (circumferential direction of the steam generating vessel 31) of the positioning recesses 31h, 31i is formed to be shorter than the circumferential length of the positioning recess 31j. The positioning recess 31h is formed at a position 60° clockwise away from a position on the cooking chamber 20 side which is the destination of the steam, the positioning recess 31i is formed at a position 60° counterclockwise away from a position on the cooking chamber 20 side which is the destination of the steam, and the positioning recess 31j is formed on the opposite side to the cooking chamber 20 which is the destination of the steam, i.e., at a position 180° away from the cooking chamber 20 side.

[0030] The positioning protrusions 44a to 44c are formed slightly shorter than the circumferential length of the positioning recesses 31h to 31j (circumferential direction of the steam generating container 31 or the frame 44), and are engageable with the positioning recesses 31h to 31j. Similarly to the circumferential length of the positioning recesses 31h and 31i being shorter than the circumferential length of the positioning recess 31j, the circumferential length of the positioning protrusions 44a and 44b is formed shorter than the circumferential length of the positioning protrusion 44c. Similarly to the positioning recesses 31h to 31j, the positioning protrusion 44a is formed at a position 60° clockwise away from the position on the cooking chamber 20 side, which is the steam destination, the positioning protrusion 44b is formed at a position 60° counterclockwise away from the position on the cooking chamber 20 side, which is the steam destination, and the positioning protrusion 44c is formed on the opposite side to the cooking chamber 20, which is the steam destination, that is, at a position 180° away from the cooking chamber 20 side.

[0031] When the shielding portion 45 is arranged on the cooking chamber 20 side, which is the steam destination, and the steam passage port 46 is arranged on the horizontal opposite side to the cooking chamber 20 side, which is the steam destination, each of the positioning protrusions 44a to 44c of the frame portion 44 can engage with the positioning recesses 31h to 31j of the steam generating vessel 31. When the shielding portion 45 is not arranged on the cooking chamber 20 side, which is the steam destination, and the steam passage port 46 is not arranged on the horizontal opposite side to the cooking chamber 20 side, which is the steam destination, each of the positioning protrusions 44a to 44c of the frame portion 44 cannot engage with the positioning recesses 31h to 31j of the steam generating vessel 31. In this way, the hot water inflow prevention member 43 is not attached to the upper part of the steam generating vessel 31 when the shielding portion 45 and the steam passage port 46 are in the wrong position with respect to the steam destination.

[0032] 10 and 12, four locking projections 44d-44g are formed to protrude upward from the upper end of the frame 44, and these locking projections 44d-44g are locked to the step between the fitting portion 41a and the receiving portion 41b of the steam receptor 41. By locking these locking projections 44d-44g to the step between the fitting portion 41a and the receiving portion 41b of the steam receptor 41, the hot water inflow prevention member 43 is restricted from moving to the upper side of the steam generating vessel 31.

[0033] 9 and 10 , a water level detection tank 50 is provided in an upright position behind the steam generating vessel 31, and a lower portion of the water level detection tank 50 is connected in communication with a lower portion of the steam generating vessel 31 by a communication pipe 51. A water level sensor 52 using a float switch is provided in the water level detection tank 50, and the water level sensor 52 detects the water level in the water level detection tank 50, thereby detecting the water level in the steam generating vessel 31. In this embodiment, the water level sensor 52 is capable of detecting an upper limit water level and a lower limit water level in the water level detection tank 50, i.e., in the steam generating vessel 31.

[0034] A water supply pipe 53 extending from a water supply source is connected to the top of the water level detection tank 50, and a water supply valve 54 (shown in FIG. 13) is provided in the water supply pipe 53 within the machine room 13 at the bottom of the housing 11. Water supplied from the water supply source is supplied into the water level detection tank 50 through the water supply pipe 53 by opening the water supply valve 54, and the water supplied into the water level detection tank 50 is supplied to the steam generating vessel 31 through the communication pipe 51.

[0035] As shown in Fig. 11, first and second partition plate portions 50a, 50b are provided in the water level detection tank 50 to separate the area below the water supply pipe 53 and the area where the water level sensor 52 is disposed, allowing water to pass through. The first and second partition plate portions 50a, 50b are intended to prevent fluctuations in the water level due to rippling around the water level sensor 52. The first partition plate portion 50a is disposed near the left rear corner where the water supply pipe 53 of the water level detection tank 50 is disposed. The first partition plate portion 50a extends from the left wall of the left rear corner toward the rear wall, and a water passage 50c is formed between the first partition plate portion 50a and the rear wall. The second partition plate portion 50b is provided in an area partitioned by the first partition plate portion 50a of the water level detection tank 50 to allow water to pass through, and is disposed between a position directly below the water supply pipe 53 and a water passage 50c formed between the first partition plate portion 50a and the rear wall of the water level detection tank 50. The second partition plate portion 50b has a function of preventing waves generated by water supplied from the water supply pipe 53 from being transmitted to the surroundings of the water level detection tank 50 through the water passage 50c.

[0036] As shown in FIG. 5, FIG. 9, and FIG. 10, a drain valve 60 is provided on the lower side of the steam generating vessel 31, and water in the steam generating vessel 31 is discharged into the drain tank 16 by opening the drain valve 60. The drain valve 60 is capable of discharging water in the steam generating vessel 31 by opening a valve body in a pipe member 60a having connection ports at the top and bottom, and a motor 60b for opening and closing the valve body is provided on the outside of the pipe member 60a. A cylindrical first socket 61 is rotatably fitted to the outer circumferential surface of the small diameter portion 31b at the lower end of the steam generating vessel 31, and the first socket 61 is attached by screwing to the upper connection port of the drain valve 60. An annular groove is formed on the outer circumferential surface of the small diameter portion 31b, and an O-ring 62 is interposed in the annular groove as a seal member. The small diameter portion 31b of the steam generating vessel 31 is liquid-tightly sealed between the first socket 61 and the O-ring 62.

[0037] A second socket 63 is screwed into the lower connection port of the drain valve 60, and the lower outer peripheral surface of the second socket 63 is rotatably fitted into the connecting cylinder portion 16a provided at the upper portion of the drain tank 16. An annular groove is formed in the lower outer peripheral surface of the second socket 63, and an O-ring 64 is interposed in the annular groove as a sealing member. The second socket 63 is liquid-tightly sealed between the connecting cylinder portion 16a of the drain tank 16 and the O-ring 64.

[0038] The first socket 61 screwed into the upper connection port of the pipe member 60a of the drain valve 60 is rotatably connected to the small diameter portion 31b of the steam generating vessel 31, and the second socket 63 screwed into the lower connection port of the pipe member 60a of the drain valve 60 is rotatably connected to the connection tube portion 16a provided at the upper part of the drain tank 16. Since the pipe member 60a of the drain valve 60 is rotatably attached to the steam generating vessel 31 and the drain tank 16 via the first and second sockets 61, 63, the motor 60b on the outside of the pipe member 60a can be rotated from a position housed in the left side machine room 12 to a position disposed outside the left side machine room 12.

[0039] As shown in FIG. 13, an IH board box 70 having an inverter circuit for supplying a high-frequency current to the induction heating coil 34 of the steam generator 30 is provided in the lower machine room 13 of the housing 11. The IH board box 70 is disposed in the middle of the lower machine room 13 in the front-rear direction and can be drawn out from the lower machine room 13 to the left machine room 12 side. As shown in FIG. 13(a), when the motor 60b of the drain valve 60 of the steam generator 30 is disposed in the left machine room 12 on the left side of the housing 11, the movement of the IH board box 70 to the left machine room 12 side is restricted by the motor 60b of the drain valve 60. As shown in FIG. 13(b), when the motor 60b of the drain valve 60 is rotated outward from the left machine room 12 on the left side, the IH board box 70 can be drawn out from the lower machine room 13 to the left machine room 12 side, and the IH board box 70 can be removed for maintenance.

[0040] As shown in Figures 13 and 14, a cooling fan 71 is provided in the lower machine room 13 of the housing 11, and the cooling fan 71 is disposed on the right side of the IH board box 70. The cooling fan 71 is attached to the lower machine room 13 by a bracket 72 so that the flow of cooling air by the cooling fan 71 faces diagonally backward. By facing the flow of cooling air by the cooling fan 71 diagonally backward, the cooling fan 71 cools not only the IH board box 70 that is the object of cooling, but also electrical components such as the water supply valve 54 disposed on the rear side of the IH board box 70. In addition, the bracket 72 separates the rear side of the lower machine room 13, so that the cooling air from the cooling fan 71 does not short-cycle between the rear of the lower machine room 13 and the cooling fan 71.

[0041] As shown by the dashed line in Fig. 13(a), when the cooling fan 71 is operated, air below the housing 11 is drawn into the lower machine room 13 through an opening 11a formed in the bottom wall of the housing 11 in front of the IH board box 70, and the air drawn into the lower machine room 13 passes through a noise filter 73 disposed above the opening to cool the noise filter 73. The air that passes through the noise filter 73 and is sent to the right side of the lower machine room 13 is sent out diagonally left rearward of the lower machine room 13 by the cooling fan 71. The sent out air passes through the IH board box 70 and electrical components such as the water supply valve 54 disposed behind it to cool the IH board box 70 and the electrical components such as the water supply valve 54.

[0042] 8 and 15, an air intake damper device 80 that introduces air into the cooking chamber 20 is provided in the front of the left side machine chamber 12 of the housing 11. The air intake damper device 80 includes a main pipe 81 extending vertically in the front of the left side machine chamber 12, an air intake valve 82 provided on the main pipe 81, a first elbow pipe 83 that bends from the lower part of the main pipe 81 towards the cooking chamber 20, and a second elbow pipe 84 that bends from the end of the first elbow pipe 83 on the cooking chamber 20 side and extends to outside air inlet 20c on the left side wall of the cooking chamber 20.

[0043] The main pipe 81 comprises a first main pipe 81a and a second main pipe 81b connected to the lower part of the first main pipe 81a, with the upper end of the first main pipe 81a protruding from an opening formed in the top plate of the housing 11 and the lower end of the second main pipe 81b extending to a position slightly higher than the outside air inlet 20c of the cooking chamber 20. The upper end of the first main pipe 81a has a rectangular cross section in the horizontal direction, and a net member 85 is provided at the upper end of the first main pipe 81a to prevent the entry of foreign objects such as insects.

[0044] A packing 86 is provided at the upper end of the first main pipe 81a, and the packing 86 liquid-tightly seals the gap between the first main pipe 81a and the ceiling wall of the housing 11. The packing 86 is made of elastically deformable rubber material and has a thick rectangular ring shape that fits onto the outer circumferential surface of the first main pipe 81a. An inwardly recessed engagement groove 86a is formed around the entire circumference on the outer circumferential surface of the packing 86 to sandwich the periphery of the opening of the ceiling wall of the housing 11 from above and below. A downwardly protruding protrusion (not shown) is formed around the entire circumference at the upper part of the engagement groove 86a, and an upwardly protruding protrusion (not shown) is formed around the entire circumference at the lower part of the engagement groove 86a. Since the opening edge of the top plate of the housing 11 is sandwiched within the engagement groove 86a, water is less likely to flow into the left side machine room 12 from between the opening of the top plate of the housing 11 and the first main pipe 81a.

[0045] The air intake valve 82 opens and closes the inside of the main pipe 81, and is interposed in the second main pipe 81b. A first elbow pipe 83 is connected to the lower end of the second main pipe 81b. The first elbow pipe 83 extends obliquely downward from the lower end of the second main pipe 81b toward the cooking chamber 20, so that the first elbow pipe 83 has few steps or horizontal parts where water can accumulate. A second elbow pipe 84 is connected to the lower end of the first elbow pipe 83, and the second elbow pipe 84 extends obliquely downward along the left side of the cooking chamber 20 toward the outside air inlet 20c. The second elbow pipe 84 has few steps or horizontal parts where water can accumulate. The air intake damper device 80 introduces outside air passing through an air intake path consisting of the main pipe 81, the first elbow pipe 83, and the second elbow pipe 84 into the cooking chamber 20, and water due to condensation is unlikely to accumulate and remain in these air intake paths. Even if condensation occurs in the air intake path when no cooking is being performed in the cooking chamber 20, the condensation does not remain in the air intake path but flows down into the cooking chamber 20. This makes it possible to prevent a sudden increase in pressure in the cooking chamber 20 caused by water flowing into the cooking chamber 20 from the air intake path of the air intake damper device 80 when air is supplied by the air intake damper device 80 during cooking in the cooking chamber 20.

[0046] 16, the cooking device 10 includes a control device 90, which is connected to the heater 25, the convection fan 26, the temperature sensor 27, the steam generator 30, and the air supply damper device 80. The control device 90 has a microcomputer (not shown), which includes a CPU, a RAM, a ROM, and a timer (all not shown) that are connected to each other via a bus.

[0047] The control device 90 has cooking programs stored in the ROM for cooking ingredients in the cooking chamber 20. The cooking programs include three types of cooking programs: a hot air mode cooking program for cooking ingredients with convecting hot air by activating the heater 25 and the convection fan 26, a steam mode cooking program for cooking ingredients with convecting hot air containing steam by activating the convection fan 26 and the steam generator 30, and a combination mode cooking program for cooking ingredients with convecting high-temperature hot air containing steam by activating the heater 25, the convection fan 26, and the steam generator 30. The ROM stores cooking programs in which the set temperature, amount of steam, and cooking time in the cooking chamber 20 are preset, and the set temperature, amount of steam, and cooking time of the cooking chamber 20 for the cooking program can be set by the user.

[0048] When the hot air mode cooking program of the cooking program is executed, the heater 25 and the convection fan 26 operate to cause the air in the cooking chamber 20 to circulate as hot air, and the food stored in the cooking chamber 20 is cooked by the convection of the hot air. When the combination mode cooking program of the cooking program is executed, the heater 25 and the convection fan 26 operate to cause the air in the cooking chamber 20 to circulate as hot air, and steam is supplied from the steam generator 30 to the cooking chamber 20, so that the hot air convecting in the cooking chamber 20 contains steam, and the food stored in the cooking chamber 20 is cooked by the convection of the hot air containing steam. When the intake valve 82 of the intake damper device 80 is opened while each cooking program is being executed, the outside air outside the housing 11 is introduced into the cooking chamber 20 through the intake air path, and the humidity in the cooking chamber 20 can be adjusted.

[0049] When the steam mode cooking program and the combination mode cooking program are executed, the control device 90 controls the operation of the steam generator 30 to supply steam into the cooking chamber 20. When the steam generator 30 generates steam, a high-frequency current is supplied to the induction heating coil 34, and an eddy current flows in each heating rod 33b of the heating element 33 due to the influence of the magnetic field generated by the induction heating coil 34, and each heating rod 33b generates heat due to the electrical resistance when the eddy current flows. The water in the steam generating vessel 31 is heated by each heating rod 33b that generates heat, and steam is generated from the water surface of the steam generating vessel 31. The steam generated in the upper part of the steam generating vessel 31 enters the steam receiver 41 through the steam passage port 46 of the hot water inflow prevention member 43, and is supplied to the cooking chamber 20 through the first inclined tube portion 41c and the delivery tube 42.

[0050] When the steam mode cooking program and the combination mode cooking program are finished, the hot water remaining in the steam generating vessel 31 is drained from the drain outlet 31d by opening the drain valve 60. When the hot water is drained from the steam generating vessel 31, the drain valve 60 is closed and the water supply valve 54 is opened, so that water supplied from the water supply source through the water supply pipe 53 is supplied to the steam generating vessel 31 via the water level detection tank 50.

[0051] The steam generating device 30 of the cooking device 10 configured as described above includes a cylindrical steam generating container 31 that stores a predetermined amount of water therein and has an outlet 31c at the top end for sending out steam and a drain outlet 31d at the bottom end for discharging water, and a heating means 32 that heats the water in the steam generating container 31 to generate steam. In this steam generating device 30, a spiral flow path is formed on the inner peripheral surface of the steam generating container 31 by forming a spiral groove 31f with the vertical direction as the spiral progression direction. When water is discharged from the drain outlet 31d at the bottom end of the steam generating container 31, the water in the steam generating container 31 swirls due to the spiral flow path formed on the inner peripheral surface and is discharged from the drain outlet 31d with great force. This makes it difficult for water with concentrated scale components to remain in the steam generating container 31, making it difficult for scale to accumulate in the steam generating container 31. Although the spiral flow path is formed by forming a spiral groove 31f on the inner circumferential surface of the steam generating vessel 31, this is not limited to this, and the spiral flow path may also be formed by forming a spiral ridge on the inner circumferential surface of the steam generating vessel 31.

[0052] In addition, a water supply port 31e for supplying water is formed at the bottom of the steam generating vessel 31, and the water inflow direction of the water supply port 31e is arranged to be along the inner peripheral surface of the steam generating vessel 31. The water flowing into the steam generating vessel 31 from the water supply port 31e flows along the inner peripheral surface of the steam generating vessel 31. In addition, the water flowing along the inner peripheral surface in the steam generating vessel 31 rises along the spiral flow path and swirls in the steam generating vessel 31, so that the scale components that are about to adhere to the inside of the steam generating vessel 31 after drainage can be washed away. In addition, when steam is generated in the steam generating vessel 31, bubbles due to water vapor adhere to the surface of the heating rod 33b, and the contact area of ​​the heating rod 33b with the water is reduced, which may reduce the efficiency of steam generation. In contrast, the water inflow direction of the water supply inlet 31e is arranged to follow the inner circumferential surface of the steam generating vessel 31. Therefore, bubbles caused by water vapor adhering to the surface of the heating rod 33b are removed by the swirling flow of water flowing into the steam generating vessel 31, thereby preventing a decrease in the efficiency of steam generation.

[0053] In the steam generating device 30 configured as described above, the heating means 32 employs an induction heating system in which the water in the steam generating vessel 31 is heated by the heating element 33 generated by the induction heating coil 34, but this is not limited to this and the water in the steam generating vessel 31 may be heated by a heater such as an electric heating wire. [Explanation of symbols]

[0054] 30...steam generator, 31...steam generating vessel, 31c...outlet, 31d...drain, 31e...water supply port, 32...heating means.

Claims

1. a cylindrical steam generating vessel for storing a predetermined amount of water therein and having an outlet at an upper end for sending out steam and an outlet at a lower end for discharging water; A steam generating apparatus comprising a heating means for heating water in the steam generating vessel to generate steam, A steam generating apparatus, characterized in that a spiral flow path is formed on the inner peripheral surface of the steam generating vessel, the spiral flow path having a vertical direction as a spiral progression direction.

2. 2. The steam generating apparatus according to claim 1, A water supply port for supplying water is formed at the bottom of the steam generating vessel, A steam generating device, characterized in that the water inflow direction of the water supply inlet is arranged along an inner circumferential surface of the steam generating vessel.

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