JPS61291751A - Air preheater for stirling engine - Google Patents

Abstract

PURPOSE:To obtain a small preheater having simple structure and high heat- exchange efficiency by constructing the air preheater for stirling engine with doughnut type double tube for flowing the preheating air through any one of said tubes while exhaust through the other thus performing heat exchange. CONSTITUTION:In order to provide heat to a heater 23 provided at the cylinder head section 20 of multi-cylinder stirling engine arranged in circle, a burner 40 is provided above. The combustion gas will heat the heater 23 then enter through a hole 61 into doughnut type pipe 53 to heat the air in the doughnut type pipe 52 arranged in said pipe 53 then discharged through an outlet 60. The heated air will enter through a pipe 63 into the burner 40 to be used as combustion air. Same function can be achieved even when the inner tube 52 is employed as the exhaust gas path.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air preheater for a Stirling engine.

(Prior Art) Conventionally, as shown in FIG. 3, in a Stirling engine, an air preheater 12 is provided on the peripheral wall of a combustion chamber 11 provided in the upper part of a Stirling engine main body 10, and combustion is carried out from the air preheater 12. As shown in FIG. 4, the air preheater 12 has an inner panel 14 and an outer panel 15 arranged with a predetermined gap between them. A corrugated panel 16 having heat conductivity is brazed to the inner peripheral panel 14 and the corrugated panel 16.
forming an exhaust gas flow path A between the outer peripheral panel 15 and the corrugated panel 16, and an air flow path B for combustion air between the outer peripheral panel 15 and the corrugated panel 16, and performing heat exchange via the corrugated panel 16; ``The heat-exchanged combustion air flows into the combustor 13 through an air inflow path 17 formed on the upper wall of the combustion chamber 11 (Japanese Patent Laid-Open No. 59-25062).

(Problems to be Solved by the Invention) In the conventional Stirling engine air preheater, the corrugated panel 16 is interposed between the inner panel 14 and the outer panel 15 as described above, and the corrugated panel 16 is The difficult installation of brazing the peaks and valleys with the panels 14 and 15 had the problem of requiring work,
In addition, since the air inflow passage 17 is formed by cutting the inside of the upper part 111a of the combustion chamber 11, the formation work is very complicated, and together with the installation work, the manufacturing cost of the Stirling engine is greatly reduced. The problem was that it was relatively expensive.

(Object of the Invention) In view of the above conventional problems, the present invention not only enables efficient heat exchange, but also has a simple structure, and
It is an object of the present invention to provide an air preheater for a Stirling engine that is easy to manufacture.

(Means for Solving the Problems) In order to achieve the above object, the present invention comprises an outer pipe 51 and a heat conductive inner pipe 52 disposed inside the outer pipe 51 with a predetermined gap 53. The combustion chamber 34 facing the combustion chamber 1140 is connected to one of the pipes 51 (or 52) through which exhaust gas passes, and also to the combustor 40.
is the other pipe 52 through which combustor air passes.
(or 51), respectively.

(Function) Since the air preheater according to the present invention is formed of a pipe, it is very easy to manufacture. In addition, since the outer pipe and inner pipe are formed in two layers, heat exchange between exhaust gas and combustion air is performed effectively between each pipe.
Furthermore, a compact air preheater is provided.

(Example) Figures 1 and 2 show an example of the present invention.
0 is a plurality of piston cylinders that are erected via a first pedestal 21a, and house a movable piston 22 inside, and are filled with an inert working gas in the heating/cooling range such as N2, N2, He, etc. ing. Numeral 23 denotes a plurality of heaters erected on the pedestal 21, the upper ends of which communicate with the upper portions (expansion spaces) of the respective piston cylinders 20, and the lower ends of which communicate with the regenerative heat exchanger 24. Although not shown, a cooler is provided at the lower end of the regenerative heat exchanger 24, and the cooler communicates with the compression space formed in the lower part of the piston cylinder 20, and allows the working gas to flow therethrough. As a result, the well-known Stirling cycle consisting of isothermal compression, isovolumic heating, isothermal expansion, and isovolume cooling of the working gas is formed, and the movable piston is driven up and down.

Reference numeral 30 denotes a box-shaped cover with an open bottom, which covers each of the piston cylinders 20 and each of the heaters 23, and is provided on the second pedestal 2Ib located above the pedestal 21a. A burner 40 that emits combustion flame C downward is attached to the center of the upper plate 31 of the cover 130, and a burner 40 that emits combustion flame C downward is attached to the center of the side plate 32 in the vertical direction. A guide plate 33 is provided, and a combustion chamber 34 is formed between the lower part of the side plate 32 and the guide plate 33.

Reference numeral 50 denotes an air preheater arranged annularly so as to cover the lower part of the side plate 32 of the cover 30, and has an outer pipe 51 and a predetermined gap 53.50 inside the outer pipe 51. It consists of an inner pipe 52 arranged at a distance.

The outer pipe 51 consists of a circulation part 51a through which the exhaust gas of the combustion chamber 34 flows, and a heat insulating part 51b made of rock wool or the like attached to the outer peripheral surface of the circulation part 51a, and is connected to the second pedestal 2'1b. A part of the pedestal 21b near the periphery is connected to an exhaust pipe 0 that communicates with outside air, and a part of the pedestal 21b near the inside is connected to a connecting pipe 1 that communicates with a part of the side plate 32 on each heater 23 side. The exhaust gas in the combustion chamber 34 is made to flow through the gap 53 between the outer pipe 51 and the inner pipe 52 via the connecting pipe 1, and is further sent to the exhaust pipe 0.

The inner pipe 52 is made of a material with good heat conductivity, such as steel, and a part of the pedestal 21b near the periphery is connected to an air supply pipe 52 through which combustion air sent by an air supply fan (not shown) flows. In addition, the upper part of the exhaust pipe 0 side is connected to an air delivery pipe 3 that communicates with the air inflow 1 (not shown) of the burner 40, and the combustion air is supplied to the inside through the air supply pipe 2. The air flows through the pipe 52 and is further fed to the burner 40 via the air delivery pipe 63.

As described above, the air preheater according to the present invention has the outer pipe 5
1 and an inner pipe 52 having heat conductivity, exhaust gas (solid line arrow) flows through the gap 53 of each pipe 51, 52, and combustion air (dotted chain line) flows into the inner pipe 52. Since the exhaust gas is passed through the combustion air (arrow), the heat of the exhaust gas is transferred to the combustion air via the inner pipe 52 and heat exchange is performed.

Moreover, each air preheater 50 has an annular pipe 51.5.
2, and the inner pipe 5 is inside the outer pipe 51.
2, the structure is simple and can be easily manufactured.

Furthermore, since the outer circumferential surface of the outer pipe 51 constitutes a heat insulating group 51b, the heat retention of the exhaust gas flowing inside the outer pipe 51 is improved, further improving the heat exchange rate.

In the above embodiment, exhaust gas is passed through the gap 53 between the outer pipe 51 and the inner pipe 52, and combustion air is passed through the inner pipe 52, but the present invention is not limited to this. That is, although not shown, the outer pipe 51
An air supply pipe 2 and an air delivery pipe 3 are connected to the inner pipe 52, and an exhaust pipe 0 and a connecting pipe 1 are connected to the inner pipe 52. Heat exchange may be performed by circulating the exhaust gases respectively.

(Effects of the Invention) As explained above, the present invention consists of an outer pipe and a heat-conductive inner pipe disposed inside the outer pipe with a predetermined gap, and the combustion chamber facing the combustor is through which exhaust gas passes. Since the combustor was connected to one of the pipes through which air for the combustor passed, and the combustor was connected to the other pipe through which air for the combustor passed, not only was heat exchanged effective, but the structure was also improved. It has the advantage that it is simple and the air preheater can be manufactured easily. Further, since the outer pipe and the inner pipe are formed in two layers, there is an advantage that the air preheater can be made smaller.

[Brief explanation of drawings]

The drawings are provided for the present invention, and FIGS. 1 and 2 show an air preheater for a Stirling engine according to the present invention, FIG. 1 is a longitudinal sectional view showing the arrangement of the air preheater, and FIG. FIG. 3 is a cross-sectional view showing the arrangement of the air preheater, FIG. 3 is a cross-sectional view showing the combustion section of a conventional Stirling engine, and FIG. 4 is a partially omitted perspective view showing the conventional air preheater. In the figure, 34... combustion chamber, 40... combustor (burner)
, 50... Air preheater, 51... Outer pipe, 52
...Inner pipe, 53...Gap. Patent applicant Sanden Co., Ltd. agent Patent attorney Old 1) Layer thickness N3 Figure 41! lI

Claims (2)

[Claims] (1) It consists of an outer pipe and a heat-conductive inner pipe arranged with a predetermined gap inside the outer pipe, and the combustion chamber facing the combustor is connected to one of the pipes through which exhaust gas passes, Further, the air preheater for a Stirling engine is characterized in that the combustor is connected to the other pipe through which combustor air passes. (2) The air preheater for a Stirling engine according to claim 1, wherein the outer peripheral surface of the outer pipe is formed of a heat insulating member.