JPH0127249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a preheating combustor for a Stirling engine, and more particularly, to a preheating combustor for a Stirling engine that prevents damage to heat transfer tubes.

As shown in FIG. 1, a preheating combustor for a Stirling engine, which is an external combustion engine, has a combustion air passage 4 between an outer pipe 2 and an inner pipe 3 that constitute a main body part 1. A combustion gas passage 6 is provided between an inner tube 3 and an outer tube 5 that constitute part 1. Furthermore, a heat exchanger tube 9 is arranged between the bottom plate of the inner tube 3 and a tube plate 8 fixed to the main body part 1, an inner tube 7 is provided between the outer tube 5 and the heat exchanger tube 9, and the inner tube The lower end of 7 is fixed to the lower end of the outer cylinder 5, and the upper end thereof is fixed to the tube plate 8. The annular space between the inner cylinder 7 and the outer cylinder 5 is used as a heat insulating wall to suppress combustion heat from escaping to the outside. An upper bowl 11 for forming a tare bag 10 is arranged on the upper part of the tube plate 8, and its outer peripheral part is bolted to the main body part 1. 12 represents a nozzle, and 13 represents a combustion core. Further, 14 is a heater, 15 is a cylinder, and 16 is a heat accumulator.

The combustion air supplied from the inlet 17 is passed through the passage 4.
After passing through the heat transfer tube 9 and being preheated by the heat in the combustion chamber 18, it is supplied from the tare bag 10 to the combustion chamber 18 via the core 13. In addition, the combustion gas is supplied to the heater 14.
After heating the heat transfer tube 9, the outer tube 5 and the inner tube 3 are heated.
It is discharged from the outlet 19 through the passage 4 between the two.

In such a conventional Stirling engine combustor, the heat transfer tube 9 reaches a high temperature of about 500°C on average,
Also, the temperature of the combustion air passage 4, etc. on the main body part 1 side is 50 to 100℃.
, the heat exchanger tube 9 expands. However, because no means is adopted to absorb this thermal expansion, the heat exchanger tube often breaks or the heat exchanger tube is not fixed to the tube sheet. Damage to the parts may occur.

This invention is intended to solve the above-mentioned drawbacks of the prior art.Basically, the inner cylinder hanging down from the outer periphery of the tube plate is opposed to the outer cylinder on the main body side, and the space between the two cylinders is Adopts technical measures that allow the nozzle to move relative to the upper bowl by placing heat insulating material on the upper bowl.
Allows the heat transfer tube to expand upward when the heat transfer tube undergoes thermal expansion. The heat insulating material between the inner cylinder and the outer cylinder has the effect of preventing combustion gas from flowing back into the tare due to the pressure difference between the tare and the combustion gas outlet and holding the inner cylinder in a predetermined position.

According to this invention, one end of the heat exchanger tube for exchanging heat between combustion air and combustion gas is fixed to a tube plate having a fuel nozzle and a combustion core, and the other end of the heat exchanger tube is for exchanging heat between combustion air and combustion gas. An inner cylinder, which is fixed to the main body part to form a passage for the tube plate, and is suspended from the outer periphery of the tube sheet, is opposed to an outer cylinder provided in the main body part via a heat insulating material, and is further fixed to the main body part. There is provided a preheating combustor for a Stirling engine, characterized in that the nozzle is disposed so as to be movable relative to the upper bowl that creates a tare between the nozzle and the tube sheet.

An embodiment of the invention will be described with reference to the attached FIG. 2.

The preheating combustor 20 for a Stirling engine consists of an air preheating part 21 and a combustion part 22 inside the air preheating part 21. The air preheating part 21 has an outer pipe 23 and an inner pipe 24. Combustion air from the air inlet 25 is introduced into the air passage between the inner and outer tubes 23 and 24. The air preheating section 21 further includes an outer tube 27 inside the inner tube 24. The space between the outer tube 27 and the inner tube 24 serves as a combustion gas passage 28, and the combustion gas is discharged to the outside from an outlet 29 provided in the inner tube 24. The combustion section 22 has a tube sheet 31 including a nozzle 29 and a combustion core 30, and an inner cylinder 32 hangs down from the outer periphery of the tube sheet 31. A plurality of heat exchanger tubes 33 are arranged inside the inner cylinder 32, and the upper ends thereof are connected to the tube plate 31.
Fixed to. The combustion section 22 is installed within the air preheating section 21 and fixes the lower end of the heat transfer tube 33 to the bottom plate of the inner tube 24 . A high temperature heat insulating material 34 is interposed in the space between the outer cylinder 27 and the inner cylinder 32.

An upper bowl 35 is bolted around the upper surface of the main body part 21, and a tare 36 is created between it and the tube plate 31. Upper bowl 35
The nozzle 29 is extended to the outside through a hole in the central part of the nozzle 29 . The nozzle 29 extends from the upper bowl 35 to the outside via the high temperature insulation material 35. 37 indicates the heater of the Stirling engine.

Combustion air blown from the inlet 25 flows through the passage 26
It enters the heat transfer tube 33 through the heat exchanger tube 33, is preheated by the heat of the combustion chamber 38, enters the tare bag 36, and is then supplied to the combustor 38 through the core 30. On the other hand, the combustion gas heats the heater 14 and then heats the heat transfer tube 33, and then the passage 28 between the outer tube 27 and the inner tube 24.
and is then discharged from the outlet 29.

The heat exchanger tubes 33 expand due to the heating of the heat exchanger tubes 33, but since the inner cylinder 32 and the tube plate 31 are not restrained by the main body portion 21, the heat exchanger tubes 33 extend upward. At this time, since the nozzle 29 is also not restrained by the upper bowl 35, it moves relative to the upper bowl 35 and does not inhibit the expansion of the heat transfer tubes 33.

The heat insulating material 34 prevents combustion gas from flowing back into the tare 35 due to the pressure difference between the tare 36 and the passage 28,
Further, the combustion section 22 is prevented from falling or flattening toward the air preheating section 21 side.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional preheating combustor for a Stirling engine, and FIG. 2 is a sectional view of a preheating combustor for a Stirling engine as an example of the present invention. In the figure: 21... Air preheating section, 22... Combustion section,
23...Outer pipe, 24...Inner pipe, 25...Inlet, 2
6...Combustion air passage, 27...Outer cylinder, 28...
Combustion gas passage, 29... nozzle, 30... core,
31... Tube plate, 32... Inner cylinder, 33... Heat exchanger tube,
34...Insulation material, 36...Tare.

Claims (1)

[Claims] 1. One end of a heat exchanger tube for exchanging heat between combustion air and combustion gas is fixed to a tube sheet provided with a fuel nozzle and a combustion core, and the other end of the heat exchanger tube is used to create a passage for combustion air and combustion gas. An inner cylinder fixed to the main body and suspended from the outer periphery of the tube sheet is opposed to an outer cylinder provided on the main body via a heat insulating material,
Furthermore, the preheating combustor for a Stirling engine is characterized in that the nozzle is arranged so as to be movable relative to an upper bowl which is fixed to the main body and forms a tare between the tube plate and the upper bowl.