JP2024107954A - Superheated steam heat treatment equipment - Google Patents

Abstract

To prevent falling of droplets from an upper nozzle as much as possible.SOLUTION: A superheated steam type heat treatment device 1 includes: a box body 2 in which a heating chamber R is formed and an inlet En and an outlet Ex are formed; conveying means 4 which conveys an article 3; and superheated steam injecting means 5 which injects superheated steam into the heating chamber R. An air curtain nozzle 13 for forming an air curtain at the inlet En and the outlet Ex is provided above the conveying means 4, and includes an upper nozzle 13A for injecting steam from an upper side to a lower side. A tubular discharge portion 22a constituting a steam supply pipe 15 is provided inside the upper nozzle 13A, and a steam discharge hole 22b for discharging the steam is provided at a position above the center of the discharge portion 22a.SELECTED DRAWING: Figure 3

Description

The present invention relates to a superheated steam heat treatment device, and more specifically to a superheated steam heat treatment device equipped with air curtain nozzles that form air curtains at the inlet and outlet of a housing.

Conventionally, a known superheated steam heat treatment device includes a box having a heating chamber formed therein and an inlet and an outlet, a transport means for transporting an object from the inlet to the outlet of the box, and a superheated steam injection means for injecting superheated steam into the heating chamber (Patent Document 1).
Furthermore, in the superheated steam heat treatment device of Patent Document 1, in order to prevent outside air from entering through the inlet and outlet, steam is sprayed and the inlet and outlet are closed with air curtains.
An air curtain nozzle for spraying steam is provided at each of the inlet and outlet, and a steam supply pipe is disposed between the steam supply means for supplying steam and the air curtain nozzle.

Patent No. 5839192

Here, the steam supplied from the steam supply means may partially turn into droplets while flowing through the steam supply piping. When the droplets fall from the air curtain nozzles of Patent Document 1, particularly the upper nozzle provided above the conveying means, there is a risk that they will adhere to the objects being conveyed.
In view of the above problems, the present invention provides a superheated steam type heat treatment apparatus capable of preventing droplets from falling from the upper nozzle as much as possible.

That is, the superheated steam heat treatment device according to claim 1 is a superheated steam heat treatment device comprising a box having a heating chamber formed therein and an inlet and an outlet formed therein, transport means for transporting an object from the inlet to the outlet of the box, superheated steam injection means for injecting superheated steam into the heating chamber, an air curtain nozzle for injecting steam to form an air curtain at the inlet and outlet of the box, steam supply means for supplying steam to the air curtain nozzle, and steam supply piping arranged between the air curtain nozzle and the steam supply means,
The air curtain nozzle is provided above the conveying means and includes an upper nozzle for spraying steam downward from above,
A tubular exhaust portion constituting the steam supply pipe is provided inside the upper nozzle, and a steam exhaust hole for exhausting steam is provided at a position above the center of the exhaust portion.

According to the above invention, the upper nozzle of the air curtain nozzle has a tubular discharge portion constituting a steam supply pipe provided therein, and a steam discharge hole for discharging steam is provided in the discharge portion.
Since the steam exhaust hole is formed at a position above the center of the exhaust portion, even if the steam turns into droplets, the droplets will not be exhausted from the steam exhaust hole and will not enter the inside of the upper nozzle, thereby preventing the droplets from falling onto articles as much as possible.

FIG. 1 is a diagram showing the configuration of a superheated steam heat treatment device according to the present embodiment. Side view explaining the air curtain nozzle Front view explaining the air curtain nozzle FIG. 1 is a perspective view illustrating an air curtain nozzle.

The present invention will now be described based on the illustrated embodiment. FIG. 1 shows a superheated steam heat treatment device 1, which comprises a box 2 having heating chambers R2 to R5 formed therein and an inlet En and an outlet Ex, a transport means 4 for transporting an article 3 from the inlet En to the outlet Ex of the box 2, and a superheated steam injection means 5 for injecting superheated steam into the heating chambers R2 to R5.
A plurality of partition walls 2a are provided inside the box 2, and these partition walls 2a form six chambers inside the box 2. Specifically, from the upstream side to the downstream side in the conveying direction of the article 3, an entrance chamber R1, four heating chambers R2 to R5, and an exit chamber R6 are formed.
Further, an opening is formed in each of the partition walls 2a, and each opening is adapted to allow passage of the article 3 transported by the transport means 4. Of the openings, the opening formed in the partition wall 2a that separates the entrance chamber R1 from the heating chamber R2 at the upstream end forms the entrance En, and the opening in the partition wall 2a formed between the exit chamber R6 and the heating chamber R at the downstream end forms the exit Ex.
The conveying means 4 is composed of a metal roller conveyor or the like, and when an item 3 such as food is conveyed by this conveying means 4 into the entrance chamber R1 of the box body 2, it is passed through the heating chambers R2 to R5 via the entrance En, and the item 3 is conveyed out from the exit Ex to the exit chamber R6.

The superheated steam injection means 5 includes a superheated steam nozzle 11 provided inside each of the heating chambers R2 to R5, and a superheated steam supply means 12 for supplying superheated steam to each of the superheated steam nozzles 11.
The superheated steam nozzles 11 are provided inside each of the heating chambers R2 to R5, as well as above and below the conveying means 4, and each of the superheated steam nozzles 11 is composed of a number of pipes (not shown) arranged in parallel in a horizontal plane, and is configured to spray superheated steam from a number of through holes formed in each pipe.
The superheated steam supply means 12 that supplies superheated steam to each of the superheated steam nozzles 11 is equipped with an air supply means such as a blower and a heating means such as an electric or combustion heater, and is configured to heat the steam to a required temperature in the high temperature range of 200 to 500°C by the heating means.
The superheated steam supplied from the superheated steam supply means 12 is sprayed from the upper and lower superheated steam nozzles 11 toward the article 3, thereby baking the article 3.

In addition, in this embodiment, the superheated steam supplied into each heating chamber R is exhausted by an exhaust means (not shown) and then returned to the superheated steam supply means 12 by a circulation piping (not shown), making it possible to circulate and use the superheated steam.
As in this embodiment, a superheated steam heat treatment apparatus 1 comprising a box 2 having heating chambers R2 to R5 formed therein and a transport means 4 for transporting an item 3 inside the heating chamber R, and which injects superheated steam into the heating chamber R to bake the item 3, is conventionally known, and various conventionally known configurations can be adopted for the configurations of the superheated steam nozzle 11, the superheated steam supply means 12, etc.

In the superheated steam heat treatment device 1 of this embodiment, an air curtain made of steam is formed at the inlet En and outlet Ex formed in the inlet chamber R1 and outlet chamber R6 to prevent air from flowing into the heating chambers R2 to R5, thereby maintaining the oxygen concentration in each of the heating chambers R2 to R5 at a low oxygen concentration.
More specifically, an air curtain nozzle 13 for spraying steam to form an air curtain is provided at each of the inlet En and the outlet Ex, and further provided is a steam supply means 14 for supplying steam to the air curtain nozzle 13, and a steam supply pipe 15 arranged between the air curtain nozzle 13 and the steam supply means 14.
Here, an exhaust port 16 is provided at the top of each of the inlet chamber R1 and the outlet chamber R6, and by adjusting the opening degree of the opening/closing valve provided at each exhaust port 16, it is possible to prevent steam from leaking out from the inlet En and the outlet Ex to the outside, and to prevent the pressure in the inlet chamber R1 and the outlet chamber R6 from becoming higher than the pressure in the heating chambers R2 to R5.
The steam supply means 14 is provided outside the case 2 and is adapted to supply steam at a lower temperature than the superheated steam.

2 and 3 show the air curtain nozzle 13 provided at the inlet En, with Fig. 2 showing a side view and Fig. 3 showing a front view, respectively. Note that the air curtain nozzle 13 provided at the outlet Ex has a similar configuration, so a description thereof will be omitted.
The air curtain nozzle 13 is composed of an upper nozzle 13A and a lower nozzle 13B provided above and below the inlet En.
The upper nozzle 13A located above the item 3 sprays steam from above downward, and the lower nozzle 13B located below the item 3 sprays steam from below upward, thereby forming an air curtain that covers the entrance En.
As shown in FIG. 2, the upper nozzle 13A and the lower nozzle 13B are provided horizontally in accordance with the width of the inlet En, and the injection port 13a is provided horizontally along the opening edge of the inlet En.
The upper nozzle 13A has a box shape as shown in Figures 3 and 4, and comprises a main body portion 13b with a roughly rectangular cross section in which a space is formed through which the steam can flow, and a spray portion 13c that is provided at the bottom of the main body portion 13b and is formed so that its width gradually narrows downward, and the spray port 13a is formed at the lower end of the spray portion 13c.
Similarly, the lower nozzle 13B has a configuration in which an ejection portion 13c in which the above-mentioned ejection port 13a is formed is provided on the upper portion of a main body portion 13b having a substantially rectangular cross section.

As described above, the upper nozzle 13A is provided above the article 3 transported by the transport means 4, and is configured to spray steam from above downward.
On the other hand, the steam supply means 14 is provided outside the case 2, and a part of the steam supply pipe 15 is disposed outside the case 2. For this reason, depending on the environment outside the case 2, a part of the steam flowing through the steam supply pipe 15 may turn into droplets due to a temperature difference or the like.
Therefore, if the liquid droplets flow directly to the upper nozzle 13A, there is a risk that the liquid droplets will become liquid droplets and fall downward from the upper nozzle 13A, and adhere to the object 3 being transported by the transport means 4.
In particular, when the item 3 is food, it is necessary to prevent such droplets from falling, since this can cause problems in terms of hygiene and quality.

Therefore, in the superheated steam heat treatment apparatus 1 of this embodiment, as shown in Figures 2 to 4, the upper nozzle 13A and the steam supply pipe 15 are configured as follows to prevent the droplets from falling. Figure 4 is a perspective view of the upper nozzle 13A.
The steam supply piping 15 is connected to the steam supply means 14 and has an external piping 15A arranged outside the case 2 and an internal piping 15B arranged inside the case 2 (see Figure 1).
Of these, the internal piping 15B branches off horizontally at the upper inside of the case 2 as shown in Figure 2, and then has a vertical portion 21 that is arranged to bypass the side of the inlet En, and midway through the vertical portion 21, it branches off into an upper supply passage 22 that supplies steam to the upper nozzle 13A, and a lower supply passage 23 that supplies steam to the lower nozzle 13B.

The upper supply passage 22 is a horizontally arranged circular tubular member that is arranged to horizontally penetrate the interior of the upper nozzle 13A and is configured so that both ends are connected to the vertical portion 21.
Of the upper supply passage 22, the portion provided inside the upper nozzle 13A constitutes a discharge portion 22a according to the present invention, and the discharge portion 22a is provided with a plurality of steam discharge holes 22b at equal intervals.
As shown in Fig. 3, the exhaust portion 22a has a circular cross section, and the steam exhaust hole 22b is provided above the center of the exhaust portion 22a. With this configuration, in this embodiment, steam is ejected obliquely upward from the steam exhaust hole 22b. Note that the steam exhaust hole 22b may be provided directly above.

The lower supply passage 23 is provided approximately horizontally from the lower end of the vertical portion 21 of the internal pipe 15B, and is then connected to the required position of the lower nozzle 13B.

According to the steam supply pipe 15 having the above-mentioned configuration, the steam supplied from the steam supply means 14 is introduced into the inside of the case 2 through the external pipe 15A and the internal pipe 15B.
At that time, particularly in the external pipe 15A, the steam is likely to turn into droplets due to the external environment, and as a result, the droplets may flow through the internal pipe 15B together with the steam.
The internal pipe 15B branches into an upper supply passage 22 and a lower supply passage 23 at the vertical portion 21, and the steam that has flowed through the upper supply passage 22 is supplied to the upper nozzle 13A.
When steam reaches the exhaust portion 22a of the upper supply passage 22 provided inside the upper nozzle 13A, the steam is sprayed into the inside of the upper nozzle 13A from the steam exhaust hole 22b provided in the exhaust portion 22a.
At this time, since the steam exhaust hole 22b is located at a position above the center of the exhaust portion 22a, even if droplets of steam flow into the upper supply passage 22, the droplets will remain below the exhaust portion 22a, and exhaust from the steam exhaust hole 22b is prevented as much as possible.
The steam injected from the discharge portion 22a into the inside of the upper nozzle 13A is injected from the injection port 13a of the upper nozzle 13A to form an air curtain at the inlet En.

On the other hand, in the lower supply passage 23, there is a risk that the condensed steam may become droplets, flow through the horizontal portion 21 of the internal pipe 15B, and then flow into the lower nozzle 13B.
However, since the lower nozzle 13B sprays steam from below to above, droplets are not sprayed from the spray nozzle 13a and therefore do not adhere to the object 3.

As described above, the superheated steam heat treatment apparatus 1 of this embodiment is characterized in that the steam supply pipe 15, particularly the upper supply passage 22 which supplies steam to the upper nozzle 13A, has an exhaust portion 22a inside the upper nozzle 13A and a steam exhaust hole 22b is provided above the center of the exhaust portion 22a.
With this configuration, it is possible to prevent as much as possible the steam droplets from flowing into the nozzle 13A, and to prevent as much as possible the droplets from falling onto the object 3.
In other words, since the steam exhaust hole 22b is located above the center of the exhaust portion 22a, even if the droplets reach the exhaust portion 22a, their own weight prevents them from moving upward from the lower half of the exhaust portion 22a, and they are not sprayed from the steam exhaust hole 22b, do not flow into the interior of the upper nozzle 13A, and are prevented from falling from the injection port 13a.

In the above embodiment, steam is used for the air curtains formed at the inlet En and outlet Ex of the box body 2, but it is also possible to use superheated steam, for example. In this case, the steam supply pipe 15 of this embodiment may be connected to the superheated steam supply means 12 so that the superheated steam is supplied to the air curtain nozzle 13.
Even in this case, even if the superheated steam turns into droplets while flowing through the steam supply pipe 15, the droplets can be stopped by the steam exhaust hole 22b provided in the exhaust portion 22a, thereby preventing the droplets from falling from the upper nozzle 13A onto the object 3 as much as possible.

REFERENCE SIGNS LIST 1 Superheated steam type heat treatment device 2 Box 3 Article 4 Conveying means 5 Superheated steam injection means 13 Air curtain nozzle 13A Upper nozzle 14 Steam supplying means 15 Steam supply piping 15A External piping 15B Internal piping 22 Upper supply passage 22a Discharge portion 22b Steam discharge hole En Entrance Ex Exit

Claims (1)

A superheated steam type heat treatment apparatus comprising: a box having a heating chamber formed therein and an inlet and an outlet formed therein; transport means for transporting an object from the inlet to the outlet of the box; superheated steam injection means for injecting superheated steam into the heating chamber; an air curtain nozzle for injecting steam to form an air curtain at least one of the inlet and the outlet of the box; steam supply means for supplying steam to the air curtain nozzle; and a steam supply pipe disposed between the air curtain nozzle and the steam supply means,
The air curtain nozzle is provided above the conveying means and includes an upper nozzle for spraying steam downward from above,
a tubular exhaust portion constituting the steam supply pipe is provided inside the upper nozzle, and a steam exhaust hole for exhausting steam is provided at a position above the center of the exhaust portion.

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