close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2404060

код для вставки
July 16, 1946.
_R. D. HALL ETAL
-HIGH TEMPERATURE FURNACE
Filed Feb. s, 1944
2,404,060
Patented July 16, 1946
2,404,060
NIT-ED
2,404,060PÀTÍEN T 'OLFÍF l
HIGH TEMPERATURE >FURNACE
-Roy lI). ~` Hall, fMillington, and ~Emìlîo Romanelli,
Bloomfield, N. 'J., assignors to Westinghouse
îEle‘ctr'ic Corporation, East -Pittsburgh, Pa., .fa
Vacorporat'ion ‘of Pennsylvania
Application 'February 3, 1944,’ Serial No. 520,874
‘7 Claims.
(CLIS-_20)
‘1
'This invention relates to furnaces, A‘and more
particularly, to such adapted *for temperatures
high enough 'to sinter andp'therwise heat treat,
tungsten and molybdenum.
The principal object of our invention, 'gener
ally considered, isa furnace -adapted'to-eñiciently
producetemperatures above `1700° C., 'whereby it
may beused'for sintering and-/or vheat treating
refractory metals such las vtungsten and’molyb
dehum.
Another object of our inventionis aiiurnace for
We have designed a »furnace capable oi pro
vidingtemperatures up to 2000o C. where molyb
denum is used as a heating element, and up to
about 2500D C. where tungsten is so used. These
furnaces >are particularly adapted ‘for treatment
of refractory articles, as in ~following the inven
tion describedand claimed in the Hall et al. ap
plication, Serial No. 511,392, liled November 23,
1943, now replaced by- Serial No. 579,080, nled Feb
ruary-Zl, i945, which refers to the lfurnace which
is here claimed.
Theprinciple involved in our furnace is to use
the radiant Aheat from wires, bars or Slabs of
high tempertures comprising an 'element formed
of tungsten or 'molybdenum wire or rods _adapted
molybdenum or tungsten disposed around the
to be heated to incandescence bythe passage of
electric current therethrough and arranged to 15 body 'to ¿be heated. 'Such heating means is, `for
insulating purposes, surrounded by reflectors dis
surround’the material to be' heated, and a series of
posed at appropriate distances, the ñrst reflector
enclosing reiiecting baffles and associated _cover
being of sheet vmo'ly’bdenum or tungsten, the
platesv supported on a refractory block, with means
former `of which is generally satisfactory, the re
for sealingsaid enclosure and admittingprotec
tive atmosphere thereto, `as well vas means ?vfor
conveniently removing the enclosure for the ap
plication and `withdrawal of the material being
treated.
Other objects and >advantagesof the invention,
relating to the particular arrangement andcon
struction of the various parts, `will become ap
parent as the description proceeds.
Referring to the drawing:
maining reflectors being-of molybdenum and/or
stainless steel either chromium plated or not,
finally ending up with one or more silver plated
steel and/or copper reflectors. The last reñect
ing means may be Veither arseparate unit or part
25 of a «Water-cooled jacket used as an outer cover
rfor ït'he furnace.
The heating element is en
closed in these layers of reflectors and a _peep
hole is desirably provided at the end of a tube
for purposes of temperature measurement. The
Fig. 1 is an axial sectional view„partly.in ele
vation, of a furnace embodying our'invention and 30 vcovering of suchva lpeep'hole-device is _preferably
of‘quartz or high melting point, low expansion
showing an article in place therein, as representa
glass, and removable »for purposes of cleaning.
tive of material which maybe heat treated.
The v`heating elements of such furnaces are
Fig.'2 is a horizontal 'sectional view on the line
mounted so 'as to take up the expansion upon
II-Il of Fig, 1„in the direction .of the'arrows.
Fig. 3 is an _axial sectional View of the peep 35 heating without distortion. It is desirable to
have'twoïha'lf-Windings of approximately parallel
hole eyepiece assembly.
elements. These wires or rods, being parallel,
form elements of a cylindrical surface of such
diameter that the article to be treated, when
withstanding such ‘high temperatures.
40 placed at or near the axis of said surface, will get
relatively uniform heat. If necessary, the Wires
Beryllia, Zirconia and .thoria will withstand
or rods may be wound with tungsten or molyb
higher than usual temperatures, lbutthe ñrst ,is
denum wire -at the points Where supported in
very expensive andzirconia and thoria vare dith
korderfto cool them, Iso that refractories such as
cult to use because of vthe lack of shock resist
ance. Carbon resistor furnaces, .known as »Arsem 45 alumina canïbe used for support. ‘Where rods of
tungsten :or molybdenum vare used, connectors of
furnaces, are not usable ’with .hydrogen Yor other
drilled ‘cars can be employed. The entire furnace
protective atmosphere ,required for fabrication »of
Furnaces designed for temperature above about
1700o C. cannot contain the ‘usual type _of re
fractories because `the latter are incapable vof
such materials‘as‘tungsten and molybdenum.
Tube furnaces involving molybdenum or tung
yand shell or jacket is desirably mounted as a
unit and designed to be placed on a flat plate
50 of refractory material. IThe shell must be ex
terial such as wire drawn through Vsuch tubes so
tended kfar enough below'the heated elements to
heated. These are Asatisfactory ‘for small long
use the furnace ~for Aprotective atmospheres such
as hydrogen, nitrogen, ‘argon or a mixture of
articles but lcannot be adapted for ‘larger Work.
sten tubes may be heated electrically and ma
Induction Yfurnaces are diñicult to use with _pro
tective `atmospheres Vat high temperatures.Í
gases, or evacuated and used asa vacuum iur
55 nace.
For vacuum purposes ’the outer contact
2,404,060
3
4
of this furnace shell and plate can be sealed, as by
means of a suitable cement.
suitably insulated therefrom, said device being
strung down and up over the annular, desirably
The stand carrying the base plate is desirably
equipped for exhausting or introducing the at
mospheres required and the plate carries on its
Alundum, lower and upper spool members 69 and
1| formed with radial elements 12 and 13 around
which the individual loops pass between slots
face a container or stand for supporting the ma
therebetween, said slots being subsequently closed
terial, article, or articles, to be heat-treated.
by desirably Alundum retainer rings 14 and 15.
The spools and rings are desirably bound together
This stand may be made of molybdenum or tung
sten coated with beryllium oxide or thoria, either
by covering plates 16 and 11, of molybdenum or
as discs or powder at the point of contact with .10 other suitable material.
the material to be heat-treated to prevent weld
The heat developed by the resistance element
ing. The purpose of this stand is to carry in
is conserved by a series of bailies, the inner one
the optimum heat zone the materials undergo
18 desirably comprising sheet molybdenum pol
ing treatment.
ished on both sides, or if very high temperatures
For purposes of loading the furnace, arrange 15 are desired similarly polished sheet tungsten may
ments can be made for either raising the insulat
be used. The next baffle 19 is desirably formed of
ing housing or lowering the stand, whichever is
stainless steel, chromium plated on both sides
more convenient. Furnaces of this type are satis
or of molybdenum. The remaining three baffles
factory to furnish temperatures sufficiently high
8|, 82 and 83 are desirably formed of steel sheet,
to sinter or coalesce tungsten to high density for 20 silver plated on both sides, all of the baffles be
fabrication purposes if the proper protective
ing supported from the upper plate 84 ofthe
and/or reactive atmosphere is used during the
treatment.
Referring to the scale drawing in detail, like
parts being designated by’ like reference char
cylindrical water jacket, also desirably formed
of steel, silver plated on both sides, as by means
of bolts 85 and 86 and top cover plates 19', 8|'
and 82,', desirably respectively formed of ma
acters, there is shown one embodiment of our in
vention comprising a radiation type furnace 42
consisting of a base 43 which may be formed of
“transita” other suitable refractory, or even a
metal plate where a vacuum is desired, upon 30
terial like that of the plates 19, 8| and 82.
In order to allow for inspection of the article,
such as that designated 3|, during the heat treat
`ment thereof, the upper plates 19', 8|', B2' and
84, as well as the plate 6D, are all provided with
which is supported a preferably circular plate 44
aligned apertures preferably coaxial with the fur
of Alundum, or the like. The plate 44, in turn,
nace and the vertical section of the inlet pipe 81,
holds a hollow cylinder 45 of beryllia or zirconia,
to the top of which a valve 88 is shown applied.
carrying a supporting cap 46 of similar material,
The housing 9| of this valve is desirably pro
on which during the sintering operation the 35 vided with a horizontal annular web portion 92
- treated articles, (or article) such as the refrac
terminating at` its outer end in an upstanding
tory metal worm 3|, rests.
threaded iiange portion 93 providing a socket or
The furnace 42 comprises an outer fluid-cooled
bezel for the reception of a transparent eye
casing 41, which may consist of hollow copper
piece 94, desirably formed of quartz or high-melt
cylinders 4B and 49 coaxially arranged and con
ing-point glass, as shown in Fig. 3. The eye
nected by annular spacing elements 5| and 52
piece 94 desirably rests on packing means 95
of brass, or other suitable material, brazed or
and is secured in place by an annular retainer
otherwise suitably connected thereto, forming an
96, thereby providing a peep hole device for sight
annular space through which water may be cir
ing down axially of the furnace, through the eye
culated, as from the inlet pipe 53 to the outlet ' piece 94, the valve 88 when opened, the vertical
pipe 54. The inner plate 49 may extend into the
section of the inlet pipe 81, and the apertures
annular cavity 55 at the base 43 for support and
previously referred to in the upper horizontal
plates.
sealing, as by said cavity holding a sealing liquid,
not shown, or if evacuated or holding gas under
From the foregoing disclosure it will be seen
pressure, by a suitable cement. The inner sur
that the furnace may be used to heat articles of
face of the water jacket plate 49 is desirably
tungsten or other refractory metal, to the high
silver plated to minimize the radiation absorbed
temperatures necessary to effect the final sinter
thereby, and closed at its upper end by a water
ing operation, by radiation from an incandescent
cooled hollow plate 56 formed of suitable metal,
refractory resistance element, the heat being con
such as copper or steel.
served by polished ancl/or bright plated baffles,
The top plate 56 may be sealed inside of and to
the whole enclosed in a water jacket, and the ar
the cylinder 49, carry a refractory or transite
ticles or material during treatment being sur
plate 60, and be provided with studs 51 and 58
rounded by a protective atmosphere, such as
to which chains or cables 59 and 6| connect for
wet hydrogen, introduced through the upper pipe
raising and lowering the same with respect to the
81, and exhausted through the lower pipe B9.
base and any article, or articles, being treated.
Although a preferred embodiment of our in
To facilitate this raising and lowering operation,
vention has been disclosed, it will be understood
the water jacket has upper and lower stiffening
that modifications may be made within the spirit
and scope of the appended claims.
rings 62 and 63 secured thereto, as by welding
We claim:
or other suitable means, and through which guides (i 5
64 and 65 pass, the lower ends of said guides be- "
1. A furnace for high temperatures comprising
ing embedded in the base 43. Alternatively, the
a refractory metal element consisting of a series
studs 51 and 5B may connect directly with one
of the elements 5| and 62.
The heating means for the furnace, in theu|present embodiment, comprise a molybdenum or
tungsten resistance device, which may be a wire
66 (or if of a large size, rods suitably connected
in series) receiving power from leads 61 and 68
passing through the water-cooled _plate 56 and_
of sections, to be heated by the passage of elec- -
tricity therealong, disposed as the elements of a
hollow cylindrical surface and arranged to di
rectly radiate heat upon material to be treated,
and a series of reflecting hollow cylindrical ele
ments coaxial with said metal element, the inner
of said elements being formed of polished molyb
denum, intermediate elements consisting of stain
A2,404,060
5
6
less steel, chromium plated on both sides, and
outer elements consisting of sheet steel, silver
with said peep holes and passing through said
casing, a valve the housing of which is secured
to said pipe, said housing having an outer socket,
plated on both sides.
2. A furnace for high temperatures comprising
a refractory metal device to be heated to incan
descence by the passage of electricity therealong,
elements thereof being arranged to surround and
directly radiate heat upon material to be treated,
a base of refractory material formed with a
groove, a series of vertically movable reflecting
baffles and an outer casing surrounding said
heated element, a pair of stiffening rings secured
to said outer casing, rods with their lower ends
embedded in said base and guidably passing
through holes in said rings, and at least one of
said baffles extending below the lower edges of the
others and telescopingly received in said groove
when in normal position.
3. A furnace for high temperatures compris
ing a refractory metal element consisting of a
series of sections, to be heated by the passage
of electricity therealong, disposed as the ele
ments of a hollow cylindrical surface and ar
and an eye piece in said socket and through which
the material undergoing treatment may be viewed
when the valve is open.
5. A furnace for high temperatures comprising
a refractory metal element shaped as a series of
sections, to be heated by the passage of elec
tricity therealong, and arranged to directly radi
ate heat upon material to be treated, and a series
of reflecting hollow cylindrical elements succes
sively surrounding said metal element, the inner
of said elements being formed of molybdenum,
intermediate elements consisting of stainless steel,
and outer elements consisting of sheet steel.
6. A furnace for high temperatures comprising
a refractory metal device, to be heated to incan
descence by the passage of electricity therealong,
arranged to form elements of a hollow gener
ally cylindrical surface to surround and directly
irradiate heat upon material to be treated, a base
of refractory material formed with a groove, a
ranged to directly radiate heat upon material to
series of reflecting baffles surrounding said device,
be treated, a series of surrounding reflecting hol
at least one of said baffles extending below the
low cylindrical elements and an outer casing dis
remainder and telescopically receivable in said
posed coaxially therewith, stiffening means se
groove, and means for guiding said bañies during
cured to said casing, means closing the upper ends
raising and lowering thereof with respect to said
base.
of said reflecting elements, a base, rods with their
lower ends embedded in said base and guidably 30
'7. A furnace for high temperatures compris
passing through holes in said rings, and means
ing a refractory metal device, to be heated to
for lifting said reflecting elements and associ
incandescence by the passage of electricity there
ated refractory metal element, with the stiffen
along, arranged to form elements of a hollow
ing means sliding on said rods, in order to allow
generally cylindrical surface to surround and
for the introduction and removal of the mate- ‘ directly irradiate heat upon material to be treated,
a series of surrounding reflecting hollow cylin
rial to be treated.
4. A furnace for high temperatures compris
drical elements of varying diameters disposed
ing a refractory metal element to be heated to
coaxially with respect to said surface, a base for
incandescence by the passage of electricity there
said furnace, means for lifting said reflecting
along, arranged to surround and directly radiate 40 elements and associated refractory metal device
heat upon material to be treated, a series of
with respect to said base, and means to guide
reflecting baffles and an outer casing surrounding
said elements during raising and lowering oper
said refractory metal element, means closing the
ations.
upper end of said series of baffles, a series of peep
ROY D. HALL.
holes through said closing means, a pipe alined 45
EMILIO ROMANELLI.
Документ
Категория
Без категории
Просмотров
0
Размер файла
525 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа