JPH0792212B2 - Gas far infrared heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas type far infrared heater suitable for heating, drying, firing and radiant heating of various articles.

[Prior Art] Conventionally, an infrared heater using electricity as a heat source is known as a sheath heater, but the power cost of the heat source is relatively high,
For this reason, infrared heaters that use gas as fuel have been developed,
For example, as seen in JP-A-59-21913, a zigzag smoke tube is connected to the tip of a circular tubular combustion chamber, and the combustion gas heats the combustion chamber to radiate infrared rays from the outer surface of the combustion chamber. Then, there is an infrared heater that heats the smoke pipe to emit infrared rays from the outer surface of the smoke pipe, and then emits infrared rays through a chimney from a blower to the outside.

[Problems to be solved by the invention]

However, the above infrared heater has a problem that uneven heating occurs at the base end portion and the tip end portion of the smoke tube that emits infrared rays, which hinders uniform and efficient heating of the object to be heated. .

Therefore, the present invention has an object to provide a gas type far-infrared heater that uniformly radiates far-infrared rays by making the temperature distribution on the far-infrared emitting surface uniform, and yet another object is to absorb infrared rays from a heated object. It is to provide a gas-type far-infrared heater that efficiently radiates far-infrared rays according to wavelength characteristics.

[Means for solving problems]

That is, the gas far-infrared heater of the present invention has one side of a box type body whose inside is covered with a heat insulating material as an opening surface, and a far-infrared radiation ceramics coated plate on the outer surface of a metal plate on the opening surface of the body. An induction pipe having a base end connected to a gas burner is provided in the main body, and a plurality of gas ejection small holes are formed in the pipe wall of the induction pipe, and an exhaust gas discharge blower is provided in the main body. The first invention characterized in that they are connected, and the far-infrared radiation ceramics in the first invention are MnO ₂ 30 to 70%, Fe ₂ O ₃ 5 to 30%, CoO 5 to 20
%, SiO ₂ 0 to 10%, Al ₂ O ₃ 0 to 10%, which is the far infrared radiation ceramics, and the far infrared radiation ceramics in the first invention are MgO 50 to 100%, Al ₂ O _{3 to} 30%,
The third invention is a far-infrared radiation ceramic composed of SiO ₂ 0 to 30%.

[Action]

In such a gas type far-infrared heater, under operating conditions, the fuel gas is burned by the gas burner, and the obtained combustion gas is introduced into the main body through the induction pipe and a part of the combustion gas is generated. Is ejected into the main body through the gas ejection small holes of the guide tube, and then discharged to the outside by the blower. At this time, the plate on the opening face of the main body is heated by the combustion gas introduced into the main body and is also heated by the radiant heat from the induction pipe heated by the combustion gas passing through the inside of the induction pipe, and the gas ejection small The combustion gas from the holes corrects the unevenness of the surface temperature of the plate to make it uniform, and by heating the plate, far infrared rays are uniformly radiated from the surface of the far infrared radiation ceramics coated on the outer surface of the plate.

Further, in the second aspect of the present invention, the infrared ray to be emitted exhibits a black body (ideal object having a total emissivity of 1) type infrared ray emission characteristic having a high emissivity over the entire wavelength range.

Further, in the third invention, the emitted infrared rays exhibit a high emissivity in the far infrared region above the wavelength of about 7 μm, and a far infrared selective emission characteristic of a low emissivity in the infrared region below that. To do.

〔Example〕

The illustrated embodiment of the invention will now be described. Fig. 1 ~
In FIG. 3, reference numeral 1 denotes a box-shaped main body having a vertical rectangular shape, the main body 1 having an upper surface as an opening surface 2 and a bottom surface,
The insides of the left and right side surfaces and the front and rear end surfaces are covered with a heat insulating material 3. In the main body 1, vertically elongated guide tubes 4 and 4 are arranged in parallel in the width direction of the main body 1, and rear rear end portions of the guide tubes 4 and 4 are penetratingly supported by the rear end portion of the main body 1 and A plurality of gas ejection small holes 6 to 6 are formed on the outer surfaces of the guide pipes 4 and 4 at appropriate intervals in the longitudinal direction, which are connected to the gas burners 5 and 5, respectively. Reference numeral 6 controls the injection amount of combustion gas, which will be described later, by adjusting the number of holes, the diameter, and the pitch. A plate 7 is provided on the opening surface 2 of the main body 1, and the plate 7 has a far-infrared radiation ceramics 8 coated on the upper surface of a metal plate 9. An exhaust gas pipe 10 is attached to the side or bottom of the main body 1 near the rear,
The outer end of 10 is connected to the exhaust gas exhaust blower 11, and the blower 11
A butterfly valve 12 is attached to the.

The far-infrared radiation ceramics 8 of the plate 7 has a black body type infrared radiation characteristic with a high emissivity over the entire infrared wavelength range, and a far-infrared radiation with a high emissivity in the far-infrared range of about 7 μm or more. There are two types, one with selective emission characteristics, and one of them is used depending on the infrared absorption wavelength characteristics of the material to be heated. The former blackbody type material is MnO ₂ 30-70%, for example 65 %, Fe ₂ O ₃ 5
30%, for example 20%, CoO5～20%, for example 10%, SiO ₂ 0
10%, for example _{3%, Al 2 O 3 0~10} %, for example, those having a 2% composition, the material of those latter far-infrared selective radiation characteristic type, MgO50～100%, for example 95%, Al ₂ O ₃ 0
˜30%, for example 3%, SiO ₂ 0-30%, for example 2%.

In this embodiment, the fuel gas is burned by the gas burners 5 and 5 and the obtained high-temperature combustion gases are introduced into the guide tubes 4 and 4, respectively, under the operating condition. The guide tube 4 is introduced from the front end into the main body 1,
It is jetted into the main body 1 from the gas jetting small holes 6 to 6 of 4, and is then discharged by the blower 11 through the exhaust gas pipe 10. At this time, the radiant heat from the induction pipes 4, 4 heated by the combustion gas reaching the inside of the main body 1 and also heated by the combustion gas passing through the inside of the induction pipes 4, 4 at this time The combustion gas from the gas ejection small holes 6 to 6 corrects the unevenness of the heating of the plate 7 to make it uniform, and the heating of the plate 7 causes the far infrared radiation from the surface of the far infrared radiation ceramics 8 on the plate surface. Is emitted.

The heating state of the plate 7 was measured as the temperature at each point a to ike on the surface of the far-infrared radiation ceramics 8 of the plate 7 as shown in FIG. 4, and the temperature at each point a to ike was shown in Table 1. Good results of uniform heating with few spots were obtained. As the measurement conditions in Table 1, "13A-supply" was used as the fuel gas supplied to the gas burners 5 and 5, and fuel of 8000 Kcal / h was consumed.

The measurement result of the radiation characteristic of the radiated infrared rays is shown in FIG. In this case, the characteristic curve 22 when the above-mentioned black body type is used for the far infrared radiation ceramics 8 becomes a curve approximate to the characteristic curve 21 of the black body, and the far infrared radiation ceramics 8 covers the entire infrared wavelength region. It exhibited radiant characteristics with high emissivity. On the other hand, when the far-infrared radiation ceramics 8 of the far-infrared selective radiation characteristic type is used, the characteristic curve 23 becomes a curve approximate to the black-body characteristic curve 21 in the far-infrared region beyond the wavelength 7 μm. Far-infrared radiation ceramics 8 exhibited a high emissivity in the far-infrared region with a wavelength of 7 μm or more.

〔The invention's effect〕

As described above, in the present invention, since the combustion gas is introduced into the main body through the guide tube and a part of the combustion gas is ejected into the main body through the gas ejection small hole of the guide tube, the plate is uniformly heated. Far infrared rays can be efficiently radiated from the ceramic layer on the surface.

In the second aspect of the invention, since the emitted infrared rays further exhibit a black body type infrared radiation characteristic, the object to be heated such as food containing water having an excellent infrared absorption characteristic over the entire wavelength range suitable for it. In the third invention, the far infrared rays to be emitted exhibit high efficiency far infrared selective radiation characteristics in the far infrared region having a wavelength of about 7 μm or more. Therefore, the third invention is suitable for this. It is suitable for heating, drying and baking synthetic resins having far infrared absorption properties.

[Brief description of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a plan view in which it is turned over, Fig. 2 is a side view, Fig. 3 is a sectional view taken along the line AA of Fig. 2, and Fig. 4 is a temperature distribution. FIG. 5 is an infrared spectral emission characteristic diagram of a part of the drawing for explanation. 1 ... Main body, 2 ... Opening surface, 3 ... Insulation material, 4 ... Induction tube, 5 ... Gas burner, 6 ... Small hole, 7 ... Plate, 8 ... Far infrared radiation ceramics, 9 ... … Metal plate,
10 …… pipe, 11 …… blower, 12 …… butterfly valve, 21, 2
2, 23 ... Characteristic curve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiro Maeda 2-84, Uejo-cho, Kasugai-shi, Aichi (72) Inventor Morikuh Matsuura 4-49 Shirakabe, Higashi-ku, Nagoya, Aichi (56) References Japanese Patent Laid-Open No. Sho 49 -92628 (JP, A) JP-A-49-51640 (JP, A) JP-A-54-10438 (JP, A) JP-A-60-215591 (JP, A) Actual development Sho-60-91928 (JP, U) ) Actually open 61-163652 (JP, U)

Claims (3)

[Claims] 1. A box-type main body whose inside is covered with a heat insulating material is used as an opening surface, and a plate in which a far-infrared radiation ceramics is coated on the outer surface of a metal plate is provided on the opening surface of the main body, and the base end is provided. An induction pipe connected to a gas burner is disposed in the main body, a plurality of gas ejection small holes are formed in the pipe wall of the induction pipe, and an exhaust gas discharge blower is connected to the main body. Gas type far infrared heater. 2. A box-type body whose inside is covered with a heat insulating material has one surface as an opening surface, MnO ₂ 30-70%, Fe ₂ O ₃ 5-30%, Co
O5～20%, and Hi設SiO ₂ 0%, the plate was coated on the outer surface of the metal plate far infrared radiation ceramics made of Al ₂ O _{3 0~10%} opening surface of the body, gas proximal A gas is characterized in that an induction pipe connected to a burner is disposed in the main body, a plurality of gas ejection small holes are formed in the pipe wall of the induction pipe, and an exhaust gas discharge blower is connected to the main body. Type far infrared heater. 3. A box-type main body whose inside is covered with a heat insulating material has one surface as an opening, MgO 50-100%, Al ₂ O ₃ 0-30%, Si
A far-infrared radiation ceramic consisting of O ₂ 0 to 30% is coated on the outer surface of a metal plate to cover the opening surface of the main body, and a guide tube whose base end is connected to a gas burner is provided in the main body. A gas-type far-infrared heater characterized in that a plurality of small gas ejection holes are formed on the wall of the induction pipe, and an exhaust gas discharge blower is connected to the main body.