U.S. patent number 3,831,380 [Application Number 05/319,542] was granted by the patent office on 1974-08-27 for hot-gas engine.
This patent grant is currently assigned to U.S. Philips Corporation. Invention is credited to Anton Marie Nederlof.
United States Patent |
3,831,380 |
Nederlof |
August 27, 1974 |
HOT-GAS ENGINE
Abstract
A hot-gas engine having a heater which is composed of pipes and
which supports an assembly of a burner device, and a fuel atomizing
device which is displaceable axially with respect to the enveloping
housing corresponding to thermal expansion of the heater pipes.
Inventors: |
Nederlof; Anton Marie
(Emmasingel, Eindhoven, NL) |
Assignee: |
U.S. Philips Corporation (New
York, NY)
|
Family
ID: |
19815150 |
Appl.
No.: |
05/319,542 |
Filed: |
December 29, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Jan 13, 1972 [NL] |
|
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7200483 |
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Current U.S.
Class: |
60/524 |
Current CPC
Class: |
F02G
1/055 (20130101) |
Current International
Class: |
F02G
1/00 (20060101); F02G 1/055 (20060101); F23k
005/00 () |
Field of
Search: |
;60/24,524 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Geoghegan; Edgar W.
Assistant Examiner: Burks, Sr.; H.
Attorney, Agent or Firm: Trifari; Frank R.
Claims
What is claimed is:
1. In a hot-gas engine including an upper part defining therein an
expansion space, a heater having a plurality of pipes disposed
generally in parallel and in the form of a cylinder about a space
for combustion gases, the heater having a near end secured to said
upper part and a remote free end, the engine further including a
burner device including therein a chamber for air and fuel, a
housing wall enveloping said heater, burner and upper part of the
engine, the chamber having a near side communicating with said
space for combustion gases and a remote side, a fuel atomizing
device on said remote side and extending through said wall, the
improvement in combination therewith wherein said fuel atomizing
device and burner device form a single rigid assembly engaged to
said remote ends of said heater pipes, the assembly being
displaceable relative to said housing axially of said heater and
movable a distance corresponding to axial expansion of said pipes
when heated, said engine further comprising a flexible seal
interconnecting said housing and said movable assembly.
2. Apparatus according to claim 1 wherein said seal is a metal
bellows having one end secured to said housing wall and the other
end secured to said fuel atomizing device.
Description
BACKGROUND OF THE INVENTION
The invention relates to a hot-gas engine provided with a heater
which comprises at least one row of pipes arranged in the form of a
cylinder about a space for combustion gases and which extend mainly
parallel to the cylinder axis. The heater has a free end supporting
a burner device provided with a chamber for air and fuel. This
chamber is bounded on its side which is remote from the heater by a
fuel atomizing device comprising an atomizer which debouches into
said chamber, the fuel atomizing device being passed to the outside
through a wall of a housing enveloping the heater and the burner
device.
Hot-gas engines of the relevant prior art are known as appears from
FIG. 1 of British Patent Specification No. 892,962 and from FIG. 13
of the article "Der Philips Stirlingmotor" (MTZ-Motortechnische
Zeitschrift 29, No. 7, July 1968); however these known hot-gas
engines have some drawbacks.
During operation of the engine, the heater pipes reach a high
operating temperature of 700.degree. C or higher. Consequently, the
heater pipes exhibit a substantial thermal expansion, with the
result that the pipe length is substantially increased. The length
increase of the heater pipes, i.e., in the axial direction of the
cylinder formed by the pipes is much greater than that of the
housing enveloping the heater and that of the pre-heater which is
usually arranged around the heater inside the housing. In the
preheater combustion air is pre-heated by the combustion gases
discharged from the engine, these combustion gases having
previously transferred most of their heat to the heater pipes.
It is obvious that this difference in expansion is mainly caused by
the fact that the mean temperatures reached by the housing and the
pre-heater are substantially lower than that of the heater. The
large difference in expansion between the heater and the enveloping
housing or the pre-heater, respectively, is the cause of a variety
of problems.
In the hot-has engine known from British Patent Specification No.
892,962, in which the burner device which bears on the heater is
mounted inside the enveloping housing so as to be rigid with
respect to this housing, the difference in expansion gives rise to
deformation of the heater pipes and of the walls of the burner
device. Consequently, leakage of the heater pipes is likely to
occur, so that the working medium present in the working space of
the engine escapes and the engine becomes inoperative. Due to the
deformation of the walls of this burner device, the orientation of
the burners is altered and the flames are liable to be directed
onto the heater pipes, which is undesirable. Moreover, the
adjustment of the burner and hence the fuel dosing is liable to be
changed.
In the hot-gas engine known from "MTZ-Motortechnische Zeitschrift"
the burner device which bears on the heater can follow the
expansion of the heater. However, a problem is that, when the
burner device moves upwards, the atomizer of the fuel atomizing
device which is rigidly connected to the housing will be situated
deeper into the chamber where the combustion of the air fuel
mixture takes place. The atomizer nozzle is then exposed to
undesirably high temperatures, which results in deformation and a
reduced service life of the atomizer.
A further drawback of the known hot-gas engines is that the
mounting and removal of the burner device and the atomizer device
can be effected only after removal of the pre-heater. This makes
mounting and disassembly time-consuming, and hence expensive.
The invention has for its object to provide a hot-gas engine of the
kind set forth in which the said drawbacks are simply
eliminated.
SUMMARY OF THE NEW INVENTION
The hot-gas engine according to the invention is characterized in
that the fuel atomizing device forms one rigid assembly with the
burner device, the assembly being displaceable with respect to the
housing in the axial direction of the heater and being capable of
following length variations of the heater which are caused by
temperature variations, at least one flexible seal being provided
between the housing and the assembly.
In the case of expansion or shrinking of the heater pipes, the
assembly of the burner device and the fuel atomizer device bearing
thereon will move freely along with the heater with respect to the
enveloping housing and the pre-heater which have a smaller absolute
thermal expansion. Consequently, no material stresses occur between
the heater with the assembly of the burner device and the fuel
atomizing device on the one side, and the housing, with or without
pre-heater, on the other side. The atomizer always remains in the
same position with respect to the burner device.
The assembly of the burner device and the fuel atomizing device can
be readily slid into and out of the housing, without removal of the
pre-heater being necessary.
Owing to its properties, the flexible seal can readily follow the
relative movement of the assembly and the housing, the sealing
action also ensuring that the overpressure under which the
combustion air is applied to the engine is not lost. As a result of
the overpressure, the combustion gases can overcome the flow
resistance encountered on their way to the outlets. The combustion
gases will thus flow to the atmosphere without further aids being
required.
The invention will now be described in detail with reference to the
drawing .
BRIEF DESCRIPTION OF THE FIGURES
FIGS. 1 and 2 are partial elevation views in section which show
diagrammatically and not to scale, two embodiments of the heating
system of a hot-gas engine.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The reference 1 in FIG. 1 denotes a cylinder in which a piston 2
and a displacer 3 can move at a phase difference with respect to
each other. The piston 2 and the displacer 3 are connected, by
means of piston rod 4 and a displacer rod 5, respectively, to a
drive system not shown. Present between the piston 2 and the
displacer 3 is a compression space 6 which communicates, via a
cooler 7, a regenerator 8 and a heater 9, with an expansion space
10 above the displacer. The heater 9 is formed by a row of pipes
which are arranged in a circle about a space 11 for combustion
gases.
The heater 9 consists of a number of first pipes 12 which open into
the regenerator 8 on the one side, and into a ring duct 13 on the
other side, and a number of second pipes 14 which are alternately
arranged between the first pipes 12 and which connect the ring duct
13 to the expansion space 10. Only two sets of first and second
pipes are shown for the sake of clarity.
Via a centrally apertured plate 16 which bears on ring duct 13, the
heater 9 supports a burner device 17 having a combustion chamber 18
which is bounded on its upper side by a fuel atomizing device 19.
The fuel atomizing device 19 comprises an atomizer 20 which opens
into combustion chamber 18. A fuel inlet 21 and an inlet 22 for
atomizing air open into atomizer 20. Combustion chamber 18 is
provided with inlet openings 23 for air. Burner device 17 and fuel
atomizing device 19 together form one rigid assembly 24.
The hot-gas engine is furthermore provided with a housing 25 which
envelops the heater 9 and also the greater part of the assembly 24.
Housing 25 comprises an inlet 26 for combustion air and an an
outlet 27 for combustion gases.
Situated inside the housing 25 is a heat-exchanger 28, the
pre-heater, which is arranged about the heater 9, and in which
combustion gases can transfer heat, on their way to outlet 27, to
combustion air which enters via inlet 26.
From inlet 26 the combustion air first flows upwards via an annular
duct 29, subsequently downwards through ducts 30, and then upwards
again via an annular duct 31, after which the combustion air enters
the burner device 17 via openings 23.
In the ducts 30 the combustion air takes up heat from combustion
gases as a result of a heat-exchange in counter flow with these
combustion gases which rise in exhaust ducts 32. The combustion
gases, formed in combustion chamber 18, reach the inlet 33 of the
exhaust ducts 32 via space 11 and after having passed the heater
pipes 12 and 14 while transferring heat thereto. The exhaust ducts
32 open on their upper side into a common annular collecting
chamber 34 which communicates with outlet 27.
Assembly 24 can be moved to and fro in the vertical direction with
respect to housing 25. Bellows 35 are provided as a flexible seal
between housing 25 and assembly 24, the bellows being connected to
the housing at the area 36 and to the assembly 24 at the area
37.
In this case the bellows 35 are situated within housing 25. When
the engine is started and the heater pipes 12 and 14 reach a high
temperature, the length of the pipes increases considerably due to
the thermal expansion. The thermal expansion of housing 25 and
preheater 28 is much less due to the lower temperature level.
Consequently, in the vertical direction a relative upward
displacement takes place of the heater 9 with respect to housing 25
and pre-heater 28. Assembly 24 is then forced upwards by heater 9.
As this assembly can move freely with respect to the housing 25,
the entire heating system remains free of material stresses which
might give rise to a variety of material deformations and leakage
of the heater pipes. Because the fuel atomizing device 19 moves
together with burner device 17, the position of atomizer 20 is not
changed with respect to combustion chamber 18. Consequently,
overheating of the atomizer is not liable to occur, and the
atomizer need not be prematurely replaced.
Assembly 24 can be readily lifted from plate 16 and be removed from
housing 25 after detachment of bellows 35 at the area 36, without
previous removal of pre-heater 28. The mounting of assembly 24 is,
of course, also very simple.
Bellows 35 not only follow the relative movement of assembly 24 and
housing 25, but also ensure that the combustion air which is
supplied via annular duct 31 cannot escape to the surroundings.
FIG. 2 shows only the upper part of a hot-gas engine. Parts which
correspond to the engine shown in FIG. 1 are denoted by the same
reference numerals but with a suffix "a". Annular duct 31a is now
separated from pre-heater 28a by a jacket 40a of a thermally
insulating material. In this case bellows 35a are not situated
inside but outside the housing 25a. The remainder of the operation
is as described for the hot-gas engine according to FIG. 1, so the
description need not be replaced. Even though bellows are shown as
flexible seals in the FIGS. 1 and 2, other seals are feasible such
as, for example, diaphragm seals.
* * * * *