U.S. patent number 3,864,909 [Application Number 05/275,336] was granted by the patent office on 1975-02-11 for thermal reactor with relatively movable internal pipe sections.
This patent grant is currently assigned to Firma Friedrich Boysen. Invention is credited to Herbert Kern.
United States Patent |
3,864,909 |
Kern |
February 11, 1975 |
THERMAL REACTOR WITH RELATIVELY MOVABLE INTERNAL PIPE SECTIONS
Abstract
A thermal reaction pipe system for use with exhaust pipes of
internal combustion engines or the like where hot gases flow
through a series of divided internal pipe sections which are
thermally insulated from an external pipe section, the internal
pipe sections being slidable relative to each other to relieve
stresses in the pipe system caused by heat expansion as well as
differing thermal expansion coefficients between internal and
external parts.
Inventors: |
Kern; Herbert (Altensteig,
Black Forest, DT) |
Assignee: |
Firma Friedrich Boysen
(Stuttgart-Heumaden, DT)
|
Family
ID: |
25761503 |
Appl.
No.: |
05/275,336 |
Filed: |
July 26, 1972 |
Foreign Application Priority Data
|
|
|
|
|
Jul 28, 1971 [DT] |
|
|
2137699 |
Jan 8, 1972 [DT] |
|
|
2200815 |
|
Current U.S.
Class: |
60/282; 60/322;
285/41; 285/53; 60/320; 60/323 |
Current CPC
Class: |
F16L
59/14 (20130101); F01N 13/1811 (20130101); F16L
59/143 (20130101); F01N 13/14 (20130101); F01N
13/08 (20130101); F16L 59/18 (20130101); F01N
3/26 (20130101); F01N 2310/02 (20130101); F01N
2310/04 (20130101); F01N 2260/022 (20130101); F01N
2260/10 (20130101) |
Current International
Class: |
F16L
59/18 (20060101); F16L 59/00 (20060101); F01N
3/26 (20060101); F01N 7/08 (20060101); F16L
59/14 (20060101); F01N 7/18 (20060101); F01N
7/14 (20060101); F01n 007/10 () |
Field of
Search: |
;60/282,320,272,322,323
;285/41,47,133,53,136,138,187,331 ;23/277C ;181/36C |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
76,109 |
|
Aug 1954 |
|
NL |
|
914,489 |
|
Jun 1946 |
|
FR |
|
Primary Examiner: Freeh; William L.
Assistant Examiner: Garrett; Robert E.
Claims
What is claimed is:
1. A thermal reactor having an entrance and a discharge end for use
with exhaust systems of internal combustion engines comprising:
an internal pipe divided into a plurality of separate sections in
communication with each other B1 and disposed adjacently to each
other along the longitudinal axis of the reactor;
joint means interconnecting two of said internal pipe sections;
an external tubular sleeve surrounding at least one of said
separate sections of said internal pipe and radially spaced
therefrom to form an annular cavity therebetween, the ends of said
external sleeve being connected in an air-tight manner to said
internal pipe;
insulating material inserted in a portion of the annular cavity
between said external sleeve and said internal pipe section, the
portion of the reactor so insulated defining a reaction zone;
and
a pressure equalization chamber disposed adjacent and rearwardly of
said reaction zone and defined by that portion of the annular
cavity between said external sleeve and said internal pipe section
in which no insulation is present, said pressure equalization
chamber being in flow communication with said internal pipe by way
of said joint means.
2. A thermal reactor as claimed in claim 1 wherein adjacent ends of
adjacent pipe sections and slidingly joined together to form a
joint permitting relative overlapping movement therebetween to
accommodate expansion of the internal pipe sections, the end of
each pipe section being slidingly received and supported in the
adjacent end of the adjacent pipe section.
3. The thermal reactor as claimed in claim 2 wherein the exit end
of at least one of said pipe sections has concentric wall portions
forming an annular recess therebetween, the entrance end of an
adjacent pipe section being slidably received in the annular recess
with minimum axial gap formed between the entrance end and the end
of the annular recess to form a labyrinth type joint between the
entrance end and the exit end of the adjacent joined internal pipe
sections.
4. The thermal reactor as claimed in claim 3 wherein the entrance
end is received in the annular recess of the adjacent exit end and
radially spaced a minimum distance from the concentric portions
forming a pocket shaped cavity with the axial gap located between
the entrance and exit ends.
5. The thermal reactor as claimed in claim 2 wherein the internal
pipe section located within the reaction zone extends outwardly
from the reaction zone toward the discharge end of the reactor, and
the entrance end of the adjacent pipe section slidingly received
and supported in the exit end of the pipe section in the reaction
zone with the sliding contact therebetween located at the discharge
end of the reaction zone.
6. The thermal reactor as claimed in claim 5 wherein the sliding
connection between the exit end and entrance end permits the loss
of a slight amount of gas from the connection as the gas passes
therebetween.
7. The thermal reactor as claimed in claim 5 wherein the internal
pipe has an expanded diameter in the area forming the reaction zone
with respect to the diameter of said entrance end so as to slow the
flow of gas therethrough.
8. The thermal reactor as claimed in claim 5 wherein the exit end
of the pipe section has concentric wall portions forming an annular
recess therebetween, the entrance end of the adjacent pipe section
being slidably received in the annular recess with slight axial and
radial gap clearance between the exit and entrance ends.
9. The thermal reactor as clained in claim 8 wherein the axial and
radial gaps formed between the entrance end and the walls of the
annular recess form a labyrinth-type joint therebetween so as to
require that gases to penetrate the joint must first reverse flow
direction to enter the annular recess, and then again reverse
direction of flow to exit from the annular recess.
10. The thermal reactor as claimed in claim 5 further comprising a
pipe located forwardly of the internal pipe reaction zone, the
forward pipe being subdivided into a plurality of branch pipes, the
entry end of each branch pipe adapted for mounting to an exhaust
from a cylinder of an internal combustion engine, an external
sleeve spaced from and surrounding the branch pipes having one end
mounted to the housing of the engine, the length of each branch
pipe being a selected multiple of its diameter, and the discharge
end of each branch pipe combining at a common connecting point
prior to the entrance end of the internal pipe to equalize the
different expansions of the branch pipes occurring during the
heating of the same.
11. The thermal reactor as claimed in claim 5 further comprising a
forward pipe section located forwardly of the internal pipe, the
pipe section being subdivided with each section discharging into
the internal pipe, an abutment mounted of the exit end of the
forward pipe section, a second abutment mounted on the entrance end
of the internal pipe adapted to engage the first abutment and
support the entrance end of the internal pipe in an axial direction
thereon, whereby in a heated condition the internal pipe may
axially expand at the sliding connection in the direction of the
flow of gases.
12. The thermal reactor as claimed in claim 11 wherein the first
and second abutments have a minimum line-of-contact therebetween
providing the minimal heat transfer between the internal pipe and
external sleeve.
13. A thermal reactor having an entrance and a discharge end for
use with exhaust systems of internal combustion engines comprising
an internal pipe divided into a plurality of separate sections in
communication with each other, an external tubular sleeve
surrounding at least one of said separate sections of said internal
pipe and radially spaced therefrom to form an annular cavity
therebetween, the ends of said external sleeve being connected in
an air-tight manner to said internal pipe, insulating material
inserted in the annular cavity between said external sleeve and
said internal pipe section, the adjacent ends of adjacent pipe
sections being slidingly joined together to form a joint permitting
relative overlapping movement therebetween, the end of each pipe
section being slidingly received and supported in the adjacent end
of the adjacent pipe section, a reaction zone defined by the
portion of the internal pipe having the insulating material
therearound, the internal pipe extending outwardly from the
reaction zone toward the discharge end of the reactor, the internal
pipe having a pipe section located in the reaction zone, and the
entrance end of the adjacent pipe section slidingly received and
supported in the exit end of the pipe section in the reaction zone
with the sliding contact therebetween located at the discharge end
of the reaction zone, the exit end of the pipe section having
concentric wall portions forming an annular recess therebetween,
the entrance end of the adjacent pipe section being slidably
received in the annular recess with slight axial and radial gap
clearance between the exit and entrance ends, the axial and radial
gaps formed between the entrance end and the walls of the annular
recess forming a labyrinth-type joint therebetween so as to require
that gases to penetrate the joint must first reverse flow direction
to enter the annular recess, and then again reverse direction of
flow to exit from the annular recess, and a chamber disposed
rearwardly of the reaction zone between the internal pipe and
external sleeve, the chamber being sealed to the atmosphere with
the gases exiting from the annular recess directly into the
chamber.
14. The thermal reactor as claimed in claim 13 wherein the chamber
is in partial communication with the insulating material located in
the area of the reaction zone.
15. A thermal reactor having an entrance and a discharge end for
use with exhaust systems of internal combustion engines comprising
an internal pipe divided into a plurality of separate sections in
communication with each other, an external tubular sleeve
surrounding at least one of said separate sections of said internal
pipe and radially spaced therefrom to form an annular cavity
therebetween, the ends of said external sleeve being connected in
an air-tight manner to said internal pipe, insulating material
inserted in the annular cavity between said external sleeve and
said internal pipe section, the adjacent ends of adjacent pipe
sections being slidingly joined together to form a joint permitting
relative overlapping movement therebetween, the end of each pipe
section being slidingly received and supported in the adjacent end
of the adjacent pipe section, the exit end of at least one of said
pipe sections having concentric wall portions forming an annular
recess therebetween, the entrance end of an adjacent pipe section
being slidably received in the annular recess with minimum axial
gap formed between the entrance end and the end of the annular
recess to form a labyrinth type joint between the entrance end and
the exit end of the adjacent joined internal pipe sections, the
entrance end being received in the annular recess of the adjacent
exit end and radially spaced a minimum distance from the concentric
portions forming a pocket shaped cavity with the axial gap located
between the entrance and exit ends, and a pressure equalization
chamber defined between a portion of the internal pipe and a
portion of the external sleeve, the radial spacing between the
outermost wall surface of the entrance end and the innermost wall
surface of the outermost concentric wall discharging into the
pressure equalization chamber.
16. The thermal reactor as claimed in claim 15 wherein the pressure
equalization chamber is located at the discharge end portion of the
reactor immediately rearwardly of the end of the insulation
material in the annular cavity.
17. A thermal reactor having an entrance and a discharge end for
use with exhaust systems of internal combustion engines comprising
an internal pipe divided into a plurality of separate sections in
communication with each other, an external tubular sleeve
surrounding at least one of said separate sections of said internal
pipe and radially spaced therefrom to form an annular cavity
therebetween, the ends of said external sleeve being connected in
an air-tight manner to said internal pipe, insulating material
inserted in the annular cavity between said external sleeve and
said internal pipe section, the adjacent ends of adjacent pipe
sections being slidingly joined together to form a joint permitting
relative overlapping movement therebetween, the end of each pipe
section being slidingly received and supported in the adjacent end
of the adjacent pipe section, a reaction zone defined by the
portion of the internal pipe having the insulating material
therearound, the internal pipe extending outwardly from the
reaction zone toward the discharge end of the reactor, the internal
pipe having a pipe section located in the reaction zone, and the
entrance end of the adjacent pipe section slidingly received and
supported in the exit end of the pipe section in the reaction zone
with the sliding contact therebetween located at the discharge end
of the reaction zone, a forward pipe section located forwardly of
the internal pipe, the pipe section being subdivided with each
section discharging into the internal pipe, a first abutment
mounted on the exit end of the forward pipe section, a second
abutment mounted on the entrance end of the internal pipe adapted
to engage the first abutment and support the entrance end of the
internal pipe in an axial direction thereon, whereby in a heated
condition the internal pipe may axially expand at the sliding
connection in the direction of the flow of gases, and the first and
second abutments covering only the upper portion of the
circumference of the internal pipe and external sleeve.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to thermal reactors for use in
exhaust pipes of internal combustion engines wherein the
combustible substances in exhaust gases are permitted to complete
combustion thereby reducing the harmful substances of the exhaust
emission from the engine.
2. Description of the Prior Art
In the pipe system comprising a thermal reactor it is required
that, due to the exceptionally high temperatures maintained in the
reactor, that the inner parts of the reactor be appropriately
insulated from the external parts in order that the inner parts may
reach and maintain the high temperatures required.
In view of the high temperatures existing in the pipe assembly,
very high stresses may occur between the internal and external
parts of these pipes in view of different thermal expansion of the
parts during operation of the reactor. Consequently, such expansion
and contraction differences eventually result in cracking or
leaking of the pipes with the reactor having to be replaced. The
expansion differences are even further increased if the materials
making up the internal parts have different thermal expansion
coefficients from the materials making up the external part, this
being the usual situation as preferably the internal parts are made
out of heat-resisting metallic alloys, such as nickel alloys which
have a high thermal expansion coefficient, while for economical
reasons a lower grade and less expensive material is used for the
external parts, such material having a lower thermal expansion
coefficient.
To cope with the different thermal expansions, it is known to
connect the external parts with the internal pipe at only one
position and support it in a sliding manner in other areas to
permit for the heat expansion. However, this design has the
significant disadvantage that mechanical forces introduced
externally of the reactor, such as tensile, compression or bending
stresses, are directly transmitted to the hot internal pipe
portions which the slidingly supported external sleeve portions are
only insignificantly stressed. These forces and stresses are a
severe disadvantage as the strength of the pipe system of the
reactor is significantly reduced with increasing temperatures
thereby significantly reducing the useful life of the reactor.
SUMMARY OF THE INVENTION
The present invention overcomes the problems and disadvantages of
the known type of thermal reactor pipe assemblies by providing an
internal pipe which is subdivided into sections which slide into or
over each other with the forces and stresses exerted thereon being
carried by the external sleeve section surrounding the internal
pipe section. Thus, the extremely hot internal pipe sections can
slide relatively to each other and will not be subjected to the
physical stresses previously encountered by prior art devices as
the external sleeve section acts as a supporting member and serves
to transfer the forces and stresses from one end of the thermal
reactor to the other without affecting the internal pipe sections
of the same. Thus, the mechanical stresses of the divided internal
pipe section are relieved with the external sleeve transmitting all
such forces and stresses in a manner bypassing the internal pipe
section of the reactor.
A further advantage of the present invention is that the internal
pipe sections may have thin walls as they will not be stressed
mechanically, thus the expensive heat resistant material required
for these internal parts can be reduced to a minimum resulting in a
substantial cost saving. Further, by providing thin pipe walls the
reduced mass and reduced heat capacity of the thin walled internal
parts will initiate a reaction more quickly to oxidize and burn up
the combustibles in the hot exhaust gases than if thick pipe walls
were provided.
Still a further advantage is that the present invention permits the
use of different materials for internal and external pipes having
different thermal expansion coefficients so that while the internal
pipe is made of expensive heat-resistant material, the external
pipe may be manufactured from a less expensive lower grade material
being resistant to scaling. When using this low grade material,
caps are attached at opposite ends for spacing the material from
the internal pipes while simultaneously joining the opposite ends
of the external sleeve to the entrance and exist ends of the
reactor, such sleeves preferably being of a high grade heat and
scale resistant material.
Still a further provision of the present invention is to provide
for a sliding seal between neighboring internal pipe sections where
the internal pipe section positioned up-stream of the direction of
gas flow through the reactor is slidingly supported by the
neighboring internal pipe section positioned down-stream of the gas
flow. This provides a joint where the gas must first reverse its
flow of direction before it can pass through the joint.
A further advantage is to provide insulating material enclosing the
internal pipe sections at least in the area where the sections
overlap in a manner sealingly bordering the overlapping joint
sections posing a resistance against any outflowing gas from the
joints.
Yet a further advantage of the invention is to provide an
insulating material between the inner and external pipe sections
with the layer of insulation material nearest the hot internal
pipes having a high density with the layer of material nearest the
external pipes having a lower density to assist in the sealing of
the joints between the hot pipe sections and preventing gas leakage
through the joints from penetrating into the insulation.
Yet a further advantage of the present invention is to provide for
the sliding relative movement of the internal pipe sections into or
on each other in a substantially airtight manner by use of a slide
sealing ring working in a fashion similar to a piston ring of an
engine so that sliding of the internal pipe sections can occur with
an airtight seal being maintained therebetween at the point of
sliding contact.
Yet a further advantage of the present invention provides a joint
seal of a non-airtight sliding manner which provides for a
labyrinth-type path which any leakage gas must pass thereby
substantially reducing any leakage along with reducing the force of
gas flow in view of the changes of gas direction required to
penetrate the labyrinth path such that there is no physical
destruction of the surrounding insulation due to the force of the
leakage gas.
A still further advantage of the invention is to provide a pressure
equalization chamber between the internal and external pipes
equalizing the pressure or vacuum formed between the sliding joints
and the insulation chamber.
A further advantage of the invention provides for insulating
material between the internal and external pipes with the
insulating material in the areas of the joints between the internal
pipes being of a gas resistant material to resist any gas leaking
through the joints.
Other features and advantages of the invention will be apparent
during the course of the following description of preferred
embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings forming a part of this specification,
and in which like reference characters are employed to designate
like parts throughout the same:
FIG. 1 is a fragmentary view in vertical section taken along the
longitudinal axis of the reactor illustrating a first embodiment of
the invention;
FIG. 2 is a fragmentary sectional view similar to FIG. 1 and
illustrating a further embodiment of the invention;
FIG. 3 is a fragmentary sectional view similar to FIG. 2 and
illustrating a further embodiment of the invention;
FIG. 4 is a fragmentary sectional view similar to FIG. 2
illustrating a further embodiment of the invention;
FIG. 5 is a fragmentary sectional view similar to FIG. 2 and
illustrating a further embodiment of the invention;
FIG. 6 is a view in vertical section illustrating an S-shaped
further embodiment of the invention;
FIG. 7 is a view in vertical section of a non-symmetrical
embodiment of the invention;
FIG. 8 is a fragmentary sectional view illustrating an alternative
way of connecting a mounting flange to the reactor of FIG. 7;
FIG. 9 is a fragmentary broken-away view in vertical section of a
further embodiment of the invention with branch pipes attached to
the internal pipe section;
FIG. 10 is a fragmentary view in vertical section of a further
embodiment of the invention showing a longitudinally divided
internal pipe and branch pipes attached thereto;
FIG. 11 is a sectional view taken along Line 11--11 of FIG. 10;
FIG. 12 is a fragmentary top view of a portion of FIG. 10;
FIG. 13 is a fragmentary broken away sectional view similar to FIG.
11 and illustrating a variation thereof;
FIG. 14 is a fragmentary view in vertical section illustrating a
sliding joint connection between internal pipe sections;
FIG. 15 is a side elevational view, partially broken away and
partially in section, of a further embodiment of the invention
utilizing an airtight sliding seal between internal pipe
sections;
FIG. 16 is a fragmentary top plan view of a portion of FIG. 15;
FIG. 17 is a sectional view taken on line 17--17 of FIG. 15;
FIG. 18 is a side elevational view in vertical section of a further
embodiment of the invention showing internal branch pipe sections
and a sliding non-airtight joint between internal pipe sections;
and
FIG. 19 is a view in partial section taken on line 19--19 of FIG.
18.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, there is shown a pipe system consisting
of three internal pipe sections 20, 21 and 22, and an external
sleeve 23. The internal pipe sections are identified as terminal
end section 20, center section 21, and end section 22. The external
sleeve 23 may be designed as a single piece section, but preferably
consists of a middle section made out of relatively plain and
inexpensive material having two end caps 24 and 25 welded to the
opposite end of the middle section with cap 24 engaging the outer
wall surface 20a of end pipe section 20 and cap 25 engaging outer
wall surface 22a of end pipe section 22. The caps 24 and 25 are
preferably manufactured out of a relatively expensive and scale
resistant material. The caps 24 and 25 are each welded in an
airtight manner to the outer surfaces 20a and 22a of the pipe
sections 20 and 22 as shown at positions 24a and 25a in FIG. 1
providing an airtight pipe system interconnecting terminal end pipe
sections 20 and 22.
The pipe sections 20, 21 and 22 are longitudinally axially aligned
with each other. One end of pipe 20 is slidingly received within
the adjacent expanded end 28 of pipe 21 with a spacing 26 between
the end of pipe section 20 and the unexpanded interior end of pipe
section 21. The opposite end of pipe section 21 is slidingly
received within expanded adjacent end 29 of pipe section 22 with a
spacing 27 between the end of section 21 and the interior
non-expanded end of section 22. A spacing 30 is present between the
exterior wall surface 20a of section 20 and the interior wall
surface of end 28 of section 21, with a spacing 31 between exterior
wall surface 21a of section 21 and the interior wall surface of end
29 of section 22. In this manner a slide joint is formed between
sections 20 and 21 with a further slide joint being formed between
sections 21 and 22. The spacings 30 and 31 of these slide joints
are just sufficient to provide for the required sliding of the
adjacent pipe sections on or in each other. Further, the selection
of which section is inserted into which section is chosen such that
the direction of gas flow through the sections, indicated generally
by arrow X, is such that the gas flowing therethrough would have to
reverse its direction of flow if it were to penetrate through the
gaps 26 and 27 along the clearances 30 and 31 to leak out of the
pipe sections.
The cavity defined between the external wall surfaces of internal
pipe sections 20, 21 and 22 and the internal wall surface of
external sleeve 23 is filled with an insulating material 32. The
insulating material provides a thermal insulation between the
external and internal pipe section and may be of a material of
higher or lower insulating density, and may include therein
aluminum, silicon, or the like. The insulating material is
preferably evenly distributed through the cavity in such a manner
that it assists in sealing and preventing gas leakage through
clearances 30 and 31 while at the same time not restricting the
sliding motion between the internal pipe sections 20, 21 and 22
when they expand and contract under the influence of the hot gas
flowing therethrough.
Referring to FIGS. 2 through 5, there are illustrated further
embodiments of the invention which are similar to the embodiment of
FIG. 1, and due to such similarity and in order to avoid needless
repetition of description, like reference numerals have been
assigned to identify like and corresponding parts between the
disclosures of FIG. 1 through FIG. 5.
Referring to the embodiment of FIG. 2, this is similar to the
embodiment of FIG. 1 except the insulating material 32 filling the
cavity defined between internal pipe sections 20, 21, 22 and
external sleeves 23 is of a layered material having an inner layer
32a of higher density surrounding the internal hot pipe sections
with the outer layer 32b being of lower density and filling the
remainder portion of the cavity. It is preferred that the
insulating material be elastic so that it can yield to heat
expansion of the wall surfaces of the internal pipe sections.
However, if insulating material is used which is not elastic, then
it is preferred that a slight clearance exists between the
insulating material and the walls of the pipe section in a cold
condition so that in a hot condition the insulating material is
resting tightly against the heat expanded wall surfaces of the
internal pipe sections.
The embodiment of FIG. 3 is similar to FIG. 1 except that the
cavity between external sleeve 23 and internal pipe sections 20,
21, 22 is filled with an insulating material 32a of high density in
juxtaposition to the sliding joints between sections 20 and 21 and
sections 21 and 22 respectively to assist in the sealing of the
clearances 30 and 31 to assist in preventing leakage of gas
therethrough. The remainder of the cavity being filled with an
insulating material 32b of lower density.
The embodiment of FIG. 4 is similar to the embodiment of FIG. 3
except that the segment of insulating material 32a associated with
clearances 30 and 31 respectively extend completely between the
sleeve 23 and internal pipe sections 20, 21, 22 with the remainder
of the cavity being filled with the insulating material 32b of
lower density.
The embodiment of FIG. 5 is similar to the embodiment of FIG. 1
with the cavity defined between external sleeve 23 and internal
pipe sections 20, 21, 22 being of the same density throughout.
However, there is additionally provided a mechanically strong and
resistent insulating sheet or foil 33, such as a nickel alloy,
which is interposed between the insulating material 32 and the hot
wall surfaces 20a, 21a, 22a of internal pipe sections 20, 21, 22.
The foil 33 is arranged in contacting juxtaposition with the wall
surfaces 20a, 21a, 22a such that even if the insulating material 32
is barely loosely arranged in the cavity the foil will serve to
prevent hot gases from leaking through clearances 30 and 31 and
penetrating into the pores or spaces between the insulating
material 32 and reaching the external sleeve 32 in a hot condition.
In addition, the foil 33 may enclose the entire insulating material
32 in order to form an insulating package so that the entire
package may be readily inserted into the cavity during assembly of
the thermal reactor while protecting the insulating material
against any damage in the handling of the same.
Referring to FIG. 6, there is shown a further embodiment similar to
FIG. 1 where the thermal reactor has been bent to a general S-shape
and includes external sleeve 123 and internal pipe sections 20, 121
and 22. The center pipe section 121 comprises the S-shaped portion
of the system with the expansion gaps 26 and 27 between opposite
ends of center pipe section 121 and terminal end pipe sections 20,
22 are each positioned in the transition of the curving pipe
section 121 to the straight pipe sections 20, 22. The external
sleeve 123 conforms in shape to the S-shape of the pipe section
with a cavity defined between the internal wall surface of external
sleeve 123 and the exterior wall surfaces of pipe sections 20, 21,
22, the cavity being filled with insulating material 32. By having
the center pipe section 121 being of the S-shape and slidingly
interconnecting end pipe sections 20, 22 with gap clearances 26 and
27 along with sliding clearances 30 and 31, compressing and bending
of the internal pipe section is precluded upon expansion when
heated. In principle, this applies not only to S-shaped pipe
sections, but also for pipes bent to other semi-circular shapes.
Further, it is to be understood that the embodiments explained
previously regarding FIGS. 1 to 5 may equally be embodied in this
embodiment of FIG. 6.
Referring now to FIG. 7, there is shown an embodiment consisting of
a bellows-type system where internal pipes 220, 221 are each
rigidly mounted at one end by flanges 233 to the housing of an
internal combustion engine (not shown), the flanges 233 being
welded to the ends of the internal pipe sections. The unmounted end
of pipe section 220 is slidably received within the unmounted
expanded end of pipe section 221 and spaced axially therefrom by
gap 226 with radial sliding clearance gap 230 between the exterior
wall surface 220a of section 220 and the interior wall surface 221a
of pipe section 221.
External sleeve 223 is spaced from the internal pipe sections 220,
221 with the ends thereof welded in an airtight manner to flange
233 to define a cavity between external sleeve 223 and internal
pipe sections 220, 221, with insulating material 232 being inserted
into the cavity. This embodiment avoids stresses caused by varying
heat expansion and provides mechanical relief to the internal
portions of the bellows pipe from mechanical strain, transferring
these loads and stresses to the external sleeve 223 which is
designed mechanically strong and airtight.
Referring now to FIG. 8, there is disclosed an alternative
embodiment to that of FIG. 7 as to the mounting of the internal
pipes 220, 221 and the external sleeve 223 to the flange 233 and
the mounting of the flange to the housing of an internal combustion
engine (not shown). In order to avoid needless repetition, only the
flange mounted end portion of internal pipe section 220 is shown,
it being understood that the same type of flange structure is used
with the flange mounted end of internal pipe section 221. In this
form of the invention, the end of the internal pipe section 220
having wall surface 220a extends up to the face side of mounting
flange 233 and is welded thereto. The flange mounted end of
external sleeve 223 extends up to the mounting flange and is welded
thereon. As before, the cavity between external sleeve 232 and the
internal pipe section is filled with an insulating material 232.
Holes 234 are located in flange member 233 externally of external
sleeve 232 for receiving screws (not shown) for mounting the
assembly rigidly to the housing of an internal combustion engine
(not shown).
Referring to FIG. 9, a further modified form of the invention is
disclosed having a plurality of internal pipe sections having
branch pipes 337, 338 connected to center pipe sections 321, 321x
respectively. Again, in order to avoid needless repetition of
description, similar reference numerals but of a higher order have
been applied to the corresponding parts as between the disclosures
of FIG. 1 and this FIG. 9. In this latter form of the invention,
the internal pipe sections are defined by reference numerals 320,
321, 321x and 322 with the external sleeve 323 extending thereover
having the end shown in the drawings welded airtight to caps 325
which in turn is welded airtight to the wall surface 322a of
terminal end pipe section 322 at point 325a. It is understood that
the opposite end of sleeve 323 is similarly provided with a cap
which is similarly welded airtight to terminal end pipe section
320. Axial clearance gaps 326, 327x and 327 along with
circumferential sliding clearances 330, 331x and 331 are provided
to form the sliding joints between sections 320 and 321, sections
321 and 321x, and sections 321x and 322. A branch pipe 337 is
connected to center pipe 321 and extends perpendicular therefrom
through the external sleeve 323, with a similar branch pipe 338
connected to center pipe section 321x and extending perpendicular
therefrom through external sleeve 323, the branch pipes adapted for
connection to the exhaust openings or pipes (not shown) of internal
combustions engines. The cavity defined between the external sleeve
323 and the pipe sections 320, 321, 321x, 322, 337, and 338 being
filled with insulating material 332.
In FIGS. 10 to 12 a further modified form of the invention is
disclosed, and in order to avoid needless repetition of description
similar reference numerals but of a still higher order have been
applied to the corresponding part as between the disclosures of
FIG. 9 and FIGS. 10-12. This latter form of the invention discloses
an internal pipe having a longitudinal wall 439 partially extending
axially therethrough separating the internal pipe into two channels
440 and 441. A branch pipe 438 has one end connected to channel 441
and extends outwardly therefrom through external sleeve 423 for
connection to the exhaust ports of cylinders of internal combustion
engines. A further branch 437 has one end slidably received in an
expanded end portion of channel 441 and is axially spaced therefrom
by axial gap 427x with circumferential sliding clearance 431x
between the wall surface 441a of branch pipe 437 and the expanded
portion of channel 441. The opposite end of branch pipe 437 is
connected to the internal combustion engine in the same manner as
branch pipe 438. It is understood that additional branch pipes,
such as 440a, may be longitudinally spaced along channel 440 in the
same manner as branch pipe 437 for interconnecting the channel to
the exhaust of an internal combustion engine. Further, it is
understood that as the longitudinal separating wall 439 only
extends through a portion of the internal pipe, that channels 440
and 441 may be united as a single internal pipe prior to
encountering the branch pipes.
The separating wall 439 is clamped between the two channel-shaped
wall sections of the internal pipe. The internal wall connected to
branch pipes 437 and 438 being divided into wall sections 441a,
441b and separated by axial expansion gaps 426, 427x and 427 from
each other and terminal end pipe sections 420a and 422a. As
previously described, each joint associated with said expansion gap
also has circumferential sliding clearance gaps 430, 431x, 431.
Channel 440 may be similarly sub-divided as channel 441. As shown,
there is provided a semi-circular shell 442 forming a pipe having
an expanded end portion 428 overlapping the adjacent neighboring
curved pipe section 440a having a wall surface 442a, with an axial
expansion gap 426a formed therebetween. The separation wall 439 is
positioned between flanges 443 and 444 of the semi-circular wall
sections 441a, 442 and folded around the flange 443 at the side
445. The shell 442 is held is position by the insulating material
432 inserted in the cavity defined between the external sleeve 423
and the internal channels and pipe sections.
Referring to FIG. 13, there is shown a more rigid mounting for
shell 442 by providing the insulating material 432 about the
flanges 443, 444 be made out of a stronger and denser insulating
material 432a while in other locations a looser or less dense
insulating material 432b can be used.
Further, it is appreciated that the external sleeve 423 can be also
assembled out of two shells 423a, 432b which are provided with
flanges and welded in an airtight manner. It is understood that
this may also be applied to all other embodiments of the invention,
and that where applicable, the external sleeve may also consist of
more than two shells welded together in an airtight manner.
Referring to FIG. 14, a further modified form of the invention is
disclosed. In order to avoid needless repetition of description,
only one end portion of the pipe assembly is shown with it being
understood that the same may extend over a multiplicity of pipe
sections depending upon the desired usage. Still further, similar
reference numerals but of a still higher order have been applied to
the corresponding parts as between the disclosure of FIG. 1 and
this FIG. 14. In this form of the invention, one end of the
internal center pipe section 521 is provided with concentric
radially spaced apart pipe walls 521a, 521b welded together at
point 521c, thus providing an annular space for slidably receiving
therein the adjacent end 522a of internal pipe section 522 with
circumferential clearances 531a, 531b formed between pipe end 522a
and pipe walls 521a, 521b. A cavity 547 is formed between walls
521a, 521b adjacent point 521c and provides the axial spacing gap
between pipes 521, 522. The external circumferential clearance 521b
communicates on one side with cavity 547 and on the other side with
a pressure equalization chamber 549 which is formed radially
between end wall 522a and external sleeve 523. The physical size of
the chamber is defined on one side by a wall 548 holding insulation
532 in the cavity defined between external wall 523 and internal
pipe sections 521, 522, and is limited on the other side by wall
section 525 forming an airtight connection between the external
sleeve 523 and internal pipe section 522.
Upon the passage of hot gases through internal pipes 521, 522 in
the direction of arrow X, heat expands the internal pipe section
521 which, by means of concentric walls 521a, 521b expands along
wall 522a. The circumferential joint clearances 531a, 531b create a
type of labyrinth seal, with any gases succeeding in passing
through the seal reaching the pressure equalization chamber 549
after changing direction of gas flow at least twice. The pressure
equalization chamber equalizes pressure variations caused by the
heated expansion of the pipes.
Referring now to FIGS. 15-18, there is disclosed two further
embodiments of the principles of the present invention wherein the
internal pipe is not divided in the reaction zone with pipe
extending in the direction of the gas flow and the sliding joint
between the pipe section being positioned outside the hottest
reaction area. The illustrations of FIGS. 15-17 illustrate one of
the embodiments, and FIGS. 18-19 illustrate the other
embodiments.
Referring now to FIGS. 15-17, there is shown a pipe system having
an elbow member 610 which is adapted for direct or indirect
mounting to the exhaust of a combustion engine (not shown).
Reference numeral 611 generally indicates a pipe assembly having
one end adjacent the elbow 610, the pipe 611 including an external
sleeve 612 and an internal pipe 613, with internal pipe 613
including internal pipe sections 614 and 615. Internal pipe section
614 is formed by an airtight welding of pipe sections 614a and 614b
at point 616. The internal pipe section 615 has one end 615a
slidingly protruding within the adjacent end of internal pipe
section 614, with the adjacent end of pipe section 614 having an
expanded portion 614c for overlapping the adjacent end of pipe
section 615. A member 617 is mounted on pipe section 615 spaced
from the end 615a of the pipe section and supports therein a seal
618 in the form of a piston ring for slidingly engaging with the
internal wall portion of pipe 614 for longitudinal movement of pipe
615 into and out of pipe 614.
The thermal reactor has a reaction zone indicated by reference
letter R extending along a section of pipe 611, it being understood
that the length of this reaction zone can be readily increased by
including therein a portion of elbow 610. The reaction zone R is
formed by the external sleeve 612, the internal pipe section 614,
with the cavity defined between the external sleeve and the
internal pipe section being filled with insulation 619. This
insulation is as discussed relative to the previous embodiments, it
being understood that the same type or types of insulation are
intended for use herein.
An angular abutment 621 is rigidly connected to the external sleeve
612 and the elbow 610 at their mutually adjacent edges, the
abutment 621 supporting thereon a disc 620 which in turn holds the
internal pipe section 614a in position. The metallic contact area
between disc 620 and angular abutment 621 is substantially only a
line type contact so that a minimum amount of heat transfer takes
place between the disc and abutment. In other words, a minimal heat
transfer therefore takes place between the internal pipe 613 and
external sleeve 612. As seen in FIG. 17, the support disc 620 and
abutment 621 only cover a portion of the total circumference with
the cavity holding the insulation 619 being restricted on one side
by support disc 620 and on the opposite side by a ring 622 which is
rigidly connected to the external sleeve 612. The direction of gas
flow through the pipes is indicated by the reference letter S such
that support disc 620 is on the gas entry side of the reaction zone
R with ring 622 being positioned at the terminal portion of the
reaction zone.
As seen in FIG. 15, the internal pipe section 614 is provided with
an enlarged diameter in the area of the reaction zone R to reduce
the speed of the gas therethrough in order to keep the gas in the
hot reaction zone for a longer period of time to assure complete
combustion thereof.
Immediately following the reaction zone R is a cooling zone K
through which the exhaust gases flow and are cooled to a reduced
temperature prior to discharge from the thermal reactor. The
external sleeve 612 is provided with port 623 positioned in the
external sleeve at the entrance to the cooling zone K of pipe
section 614. The ports have associated therewith a plurality of
vanes 624 for directing cooling air in the direction of arrow X
therethrough into the inner portions of the external sleeve wherein
annulus chamber 625 is defined between external sleeve 612 and
internal pipe 613. It is to be appreciated that when the present
invention is applied to a vehicle, when directed by the vanes is
guided in the direction of arrow X into the annulus chamber 625 and
against the internal pipe 613 subjecting the same to a cooling
effect which is high enough to cool the exhaust gases within the
cooling zone K.
The sliding point of contact between seal 618 and pipe end 614c,
indicated by point G, is thus subjected to an intensive cooling
effect since point G is located a substantial distance away from
the reaction zone R. Further, as the gap 626 between the end of
pipe 615 and the internal wall surface of the adjacent end of pipe
613 is maintained at a minimum, only cooled gases pass through the
sliding point G.
The cooling air, after flowing through the annulus chamber 625
exists therefrom in the rearward area of the cooling zone K by
being discharged to the atmosphere through ports 627 and 628
disposed in external sleeve 612, such discharge taking place after
the cooled air has cooled the sliding point G.
The rearward portion of the external sleeve 612 is manufactured as
a separate element 629 and is welded during assembly to the
rearward portion of external sleeve 612. This weld joint may serve
as a convenient mounting point for mounting clamp 630 in order to
attach the thermal reactor to a part of the vehicle (not
shown).
When the internal pipe 613 expands by virtue of the high
temperatures inside the reaction zone in the area of 1,100.degree.C
to 1,200.degree.C, the expansion therein occurs only by a sliding
movement of internal pipe section 614 along internal pipe section
615 at sliding point G. In view of the intensive cooling in cooling
zone K, the temperature at the sliding point G is reduced several
hundred degrees centigrade over the temperature prevalent in the
reaction zone R, thereby substantially extending the useful life of
seal 618. Any attempt at shifting within the reaction zone R is
prevented by the abutment 621 which supports the internal pipe
614.
Referring to FIGS. 18 and 19, there is illustrated a further
embodiment of the invention which, while similar to the embodiment
of FIGS. 15-17, differs therefrom as to the type of elbow structure
connecting the reactor to the engine housing, along with other
structural differences including the elimination of the sliding
contact between the internal pipe sections. In this form of the
invention, reference numeral 711 generally indicates a pipe system
which includes an elbow 710, an external sleeve 712, and an
internal pipe 713, which internal pipe 713 includes internal pipe
sections 714 and 715. The gas flow through the pipe system is
indicated by the direction of arrow S. The elbow 710 contains
therein two separate branch pipes 733 and 734 around which is
arranged external sleeve 731 with insulation 732 filling the cavity
defined between the external sleeve and the branch pipes. An end
733a of branch pipe 733 is inserted into a center bore of a flange
735 and welded thereto in an airtight manner, with an adjacent end
734a of branch pipe 734 being similarly inserted and welded to a
center bore of a flange 736. Flanges 735, 736 are adapted for rigid
mounting to an engine housing of an internal combustion engine (not
shown). One end of external sleeve 731 is attached and welded to
the flanges 735, 736, with the opposite end of the external sleeve
terminating co-planar with the opposite ends of branch pipes 733,
734 with the branch pipes contacting the external sleeve only along
a line-of-contact indicated by reference numeral 737.
The internal pipe section 714 is held in position by a support disc
720 mounted at the end of the pipe section adjacent the elbow 710,
the disc 720 being supported on an angular abutment 721 which is
rigidly connected to the adjacent end of the elbow. As in the
embodiment of FIGS. 15-17, the metallic contact area of disc 720 to
abutment 721 is substantially a line type contact so that a minimum
heat transfer takes place between internal pipes 714, 733, 734 and
external sleeves 712, 731.
As to the contact point 737 between internal branch pipes 733, 734
and external sleeve 731, it is to be appreciated that such contact
point is spaced a distance from the flanges 735, 736 equal to a
multiple of the pipe diameters of the branch pipes which are
selected depending upon the intended usage for the invention. The
branch pipes 733, 734 terminate at contact point 737 and are united
into a single enlarged internal pipe section 714. As the elbow 710
forms a part of the reaction zone (that zone indicated by reference
letter R in FIG. 15), the internal branch pipes 733, 734 form a
freely expanding and flexing type yoke which is on one end rigidly
connected to the engine housing by flanges 735, 736 and on the
other end combined at contact point 737 into a single internal pipe
section 714. Forces and stresses on the internal branch pipe 733,
734 caused by different heat expansion of the internal pipes or
external sleeve 731 therefore do not lead to high stresses or
cracks in the pipe system in view of this freely expanding and
flexing yoke structure providing appropriate yield characteristics
for the pipes.
As previously indicated, the internal pipe 713 is subdivided into
internal pipe sections 714 and 715 in a manner similar to the
embodiment of FIGS. 15-17. However, differing from said embodiment
the sliding contact point of the present invention, indicated by
reference letter G1, is located in the terminal portion of the hot
reaction zone R which is surrounded by insulation 719 filling the
cavity defined by internal pipe 713 and external sleeve 712.
The end of internal pipe section 714 opposite the end attached to
elbow 710 is provided with two concentric pipe walls 738, 739
weldedly attached to each other at their inwardly most ends to
create an annular chamber 740 therebetween. An adjacent end 715a of
pipe section 715 is slidably received between pipe walls 738, 739
and protrudes into annular chamber 740 with minimum circumferential
radial clearances 741, 742 between the pipe walls and the end of
pipe section 715 so that a labyrinth-like seal is created. An
annular cavity 725 is defined between pipe section 715 and external
sleeve 712, the end of annular chamber 725 adjacent insulation 719
being partially separated from the insulation by an annular disc
744 leaving a slight area 743 for communication between the
insulation 719 and annular chamber 715. The opposite end of chamber
725 is sealed in airtight manner to pipe section 715.
In view of this sliding joint connection between pipes 714 and 715,
the exhaust gases flowing in direction of arrow S through these
pipes can only enter the joint clearance 742 by reversing flow
direction as seen arrows s1, after which the gases must again
reverse flow direction in the annular cavity 740 prior to passing
through clearance 741 and entering into annular chamber 725. In
this manner insulation 719 is not strained by pulsating gases in
annular chamber 725 so that the insulation is protected against
premature destruction.
The volume of gas in annular chamber 725 may be considered an
equalization volume as the gases are contained therein in an almost
stationary condition. Simultaneously, annular chamber 725 also
protects the external sleeve 712 against the high temperatures of
internal pipe 715.
It is to be understood that the forms of the invention herewith
shown and described are to be taken as preferred embodiments of the
same, and that other forms and embodiments of the thermal reactor
are possible in a manner in accord with the invention so that
various changes in the shape, size, and arrangement of parts may be
resorted to without departing from the spirit of the invention or
the scope of the subjoined claims.
* * * * *