Patent Publication Number: US-9423121-B2

Title: Superheated-steam generator device

Description:
TECHNICAL FIELD 
     The present invention relates to a superheated-steam generator device, and more particularly to a superheated-steam generator device that includes a steam-heating pipe that has a simple, steam-loop-back structure, and that allows heaters to be individually attached to or removed from said device. 
     BACKGROUND 
     Superheated steam is steam obtained by further heating steam that is at 100° C. For example, a superheated-steam oven cooks foodstuffs by directly blowing superheated steam to the foodstuffs so as to bake them. The food-cooking apparatus disclosed in JP-A-2004-24322 connects multiple steam-heating pipes, into each of which a heater is inserted, with short non-heating pipes. The food-cooking apparatus disclosed in that prior-art document has the following characteristics: (1) because there is only a small space in the food-cooking apparatus, it is difficult to weld the short non-heating pipes onto the steam-heating pipes; (2) in order to connect the short non-heating pipes to the steam-heating pipes, holes must be drilled in the steam-heating pipes; and (3) the food-cooking apparatus is generally box-shaped, having a large width and a large depth despite having a low height. Therefore, if the food-cooking apparatus (i.e., superheated-steam generator) is to be formed into a cylindrical shape like a device, the welding of the short non-heating pipes onto the steam-heating pipe is very difficult. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     [Patent Document 1] JP-A-2004-24322 
     SUMMARY 
     Technical Problem To Be Overcome 
     Because the prior-art is such that it is difficult to form a superheated-steam generator into a cylindrical shape like a device, what has been needed is a superheated-steam generator device that has a simple, steam-loop-back structure and that connects multiple steam-heating pipes, into each of which can be inserted a heater that has short non-heating pipes and hence does not need separate short non-heating pipes, which are difficult to connect to the steam-heating pipe 
     Solution to the Problem 
     The superheated-steam generator device of the present invention includes a first disc, a second disc, a third disc, a fourth disc, and a fifth disc; the first disc, the third disc, and the fourth disc all have multiple through-holes that are arranged so as to be aligned along the same axis; the second disc has at least one long through-hole ( 7 ) and a through-hole ( 6   a ), and the long through-hole ( 7 ) interconnects two of the through-holes of the first disc with two of the through-holes of the third disc, and the through-hole ( 6   a ) interconnects one of the through-holes of the first disc with one of the through-holes of the third disc; multiple steam-heating pipes are attached to the third disc at the front end of each steam-heating pipe and are attached to the fourth disc at the back end of each steam-heating pipe; the fifth disc has at least one loop-back groove and a through-hole ( 6   b ), with the loop-back groove being dug so as to interconnect two of the through-holes of the fourth disc, and the through-hole ( 6   b ) aligns with one of the through-holes of the fourth disc; a heater having spiral fins is inserted through the through-hole of the first disc, with the attaching part ( 12 ) of the heater being screwed into the through-hole of the first disc so as to cover that through-hole; a steam-supply pipe is connected to one of the through-holes of the first disc so as to feed steam into the through-hole ( 6   a ) of the second disc; and a steam-discharge pipe is connected to the fifth disc so as to align with the through-hole ( 6   b ) of the fifth disc. 
     The attaching part ( 12 ) has a gap such that the inside of the center hole of the fastening part ( 12   a ) is separated from the main tube ( 19 ) of the heater. 
     Advantageous Effects 
     The superheated-steam generator device of the present invention includes a first disc, a second disc, and a third disc, with the second disc having long through-holes that respectively interconnect two through-holes of the first disc with two through-holes of the third disc, whereby little space is required to loop back heated steam in the device, without using short pipes. Each heater has an attaching part that is screwed into the through-hole of the first disc, and therefore the heater can easily be attached to or removed from the device. Accordingly, if the superheated-steam generator device stops functioning properly due to one defective heater, only that one heater need be replaced. Spiral fins that have large surface areas are in contact with the steam, so that the fins effectively heat the steam. 
     The attaching part is configured such that a gap is made between the center hole of the fastening part and the main tube of the heater, whereby transfer of heat from the fastening part to the main tube is prevented, the heat of the main tube is released from the gap, and the thermal effect on a feeder cable of the heat generated by the heater  11  is reduced. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a front view of a superheated-steam generator device of the present invention. 
         FIG. 2  is a side view along arrows A-A in  FIG. 1 , of the superheated-steam generator device from which heaters have been removed. 
         FIG. 3  is a cross-sectional view taken along line B-B of  FIG. 2 . 
         FIG. 4  is an exploded perspective view of the components of the superheated-steam generator device of the present invention. 
         FIG. 5  is a schematic view showing the structure constituted by the first through third discs of  FIG. 4  for looping back steam. 
         FIG. 6  is a schematic view showing the structure constituted by the fourth and fifth discs of  FIG. 4  for looping back steam. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the accompanying drawings, an exemplary embodiment of the present invention is described below. 
     Example 
       FIG. 1  is a front view of a superheated-steam generator device of the present invention. The superheated-steam generator device  100  is cylindrical, and steam is supplied from a steam-supply pipe  9  at the front of the superheated-steam generator device  100  (the left side in  FIG. 1 ), is heated by a heater  11 , and is discharged into an oven via a steam-discharge pipe  10  at the back of the superheated-steam generator device  100  (the right side in  FIG. 1 ). The superheated-steam generator device  100  is mounted to an oven wall using mounting screws  17 . The superheated-steam generator device  100  is about 50 centimeters long, and has a diameter of about 11 centimeters. 
       FIG. 2  is a side view of the superheated-steam generator device from which heaters have been removed, viewed along the arrows A-A in  FIG. 1 . The side of the device, which is round, has seven through-holes  6 , each of which has an internal screw thread  15 . 
       FIG. 3  is a cross-sectional view taken in the line B-B of  FIG. 2 . The heaters  11  are electric heaters. and each heater  11  has a feeder cable  12   d  on the left (shown in  FIG. 5 ). The main tube  19  of the heater  11  is long and narrow and is inserted into and attached to a steam-heating pipe  18 . The main tube  19  has spiral fins  13  that have large surface areas in contact with the steam that is injected into the steam-heating pipe  18 , thereby improving the heating efficiency of the steam-heating pipe  18 . The steam supplied from the steam-supply pipe  9  moves to the right through the steam-heating pipe  18  and then turns back to the left. This movement of the steam is repeated seven times, and then the steam is fed into the oven via the steam-discharge pipe  10 . A temperature sensor  16  is provided at the discharging outlet of the steam-discharge pipe  10 , whereby the temperature of the steam can be measured. 
       FIG. 4  is an exploded perspective view of the components of the superheated-steam generator device of the present invention. The front of the superheated-steam generator device  100  has a first disc  1 , a second disc  2 , and a third disc  3 , and the back of the superheated-steam generator device  100  has a fourth disc  4  and a fifth disc  5 . The first disc  1 , the third disc  3 , and the fourth disc  4  have odd numbers of multiple through-holes  6 , which are arranged so as to be aligned along the same axis. The second disc  2  has multiple, for example, three, long through-holes  7 , through each of which two of the through-holes  6  of the first disc  1  and two of the through-holes  6  of the third disc  3  are interconnected. If there are three steam-heating pipes  18 , the number of the long through-hole  7  may be one. Also, the second disc  2  has a through-hole  6   a  through which one of the through-holes  6  of the first disc  1  and one of the through-holes  6  of the third disc  3  are interconnected. 
     The steam-heating pipe  1  is welded to the through-holes  6  of the third disc  3  at its front end, and is welded to the through-holes  6  of the fourth disc  4  at its back end. The fifth disc  5  has a loop-back groove  8 , which is dug so as to interconnect two of the through-holes  6  of the fourth disc  4 . Also, the fifth disc  5  has a through-hole  6   b,  which aligns with one of the through-hole  6  of the fourth disc  4 . In this example, there are seven steam-heating pipes  18 . 
     The heater  11  is inserted through the through-hole  6  of the first disc  1 , in which through-hole  6  an attaching part  12  is screwed. Therefore, the heaters  11  can be individually attached to or removed from the device. The heater  11  has spiral fins  13  that have large surface areas in contact with the steam. The heater  11  is attached to the inside of the steam-heating pipe  18  so as to directly heat the steam that passes through the steam-heating pipe  18 . In this example, there are six heaters  11 . 
     The steam-supply pipe  9  is connected to one of the through-holes  6  of the first disc  1  so as to feed the steam to the through-hole  6   a  of the second disc  2 . The steam goes through the through-hole  6  of the third disc  3  at the six o&#39;clock position, passes through the steam-heating pipe  18 , and arrives at the through-hole  6  of the fourth disc  4  at the six o&#39;clock position, and then is turned back at the loop-back groove  8  of the fifth disc  5 . Subsequently, the steam goes through the through-hole  6  of the fourth disc  4  at the eight o&#39;clock position, passes through the steam-heating pipe  18 , and arrives at the through-hole  6  of the third disc  3  at the eight o&#39;clock position, and is turned back at the long through-hole  7  of the second disc  2 . This movement of the steam is repeated, and the steam is finally fed into the oven via the steam-discharge pipe  10 , which is configured so as to align with the through-hole  6   b  in the center of the fifth disc  5 . 
       FIG. 5  is a schematic view showing the loop-back structure constituted by the first through third discs of  FIG. 4  for looping back steam. The long through-hole  7  of the second disc  2  is constituted so as to interconnect two through-holes  6  of the first disc  1  with two through-holes  6  of the third disc  3 , and the through-holes  6  of the first disc are covered by the attaching parts  12  of the heaters  11 . Therefore, the steam returning from the back to the front of the steam-heating pipe  18  is turned back to the back of that pipe. The attaching part  12 , which is attached to one end of the main tube  19 , consists of a fastening part  12   a,  a flange  12   b,  and a screw part  12   c  that are integrally formed. The male screw of the screw part  12   c  is screwed to the female screw of the through-hole  6  of the first disc  1 . At the center of the attaching part  12  is a center hole through which the main tube  19  penetrates and in which the flange  12   b  and the screw part  12   c  are joined to the main tube  19  and are sealed so that steam does not leak from the steam-heating pipe  18 . Also, the fastening part  12   a  has a predetermined gap between the center hole and the outside of the main tube  19 , whereby the heat of the heater  11  transferred to the fastening part  12   a  is released to the outside so that very little heat is conducted to the feeder cable  12   d.    
       FIG. 6  is a schematic view showing the structure constituted by the fourth and fifth discs of  FIG. 4  for looping back steam. The steam is turned back at the loop-back groove  8  of the fifth disc  5 . 
     The number of steam-heating pipes  18  is not limited to seven as in the above example, but, for example, can be increased to nine or decreased to five. Also, the number of heaters  11  is not limited to six as in the above example, which number is one less than the number of the steam-heating pipes  18 , but may be increased to seven. In such a case, it is necessary only to drill eight through-holes  6  in the first disc  1 , and to modify the through-hole  6   a  of the second disc  2  into a long through-hole  7 . However, if the outer diameter of the superheated-steam generator device is not enlarged, it is necessary to decrease the diameter of the through-hole  7 , which increases the number of heaters using small-diameter heaters. 
     INDUSTRIAL APPLICABILITY 
     The present invention provides a compact superheated-steam generator device having a simple loop-back structure.