[TECHNICAL FIELD]
[0001] The present invention relates to an integrated MoSi
2 heating element in which the terminal part and the heat generating part are formed
from the same material and which yields effects of being able to achieve greater energy
saving than conventional heaters and improve isothermal properties, as well as to
a method of producing such a heating element.
[0002] Note that the MoSi
2 plate-shaped heating element used in the present specification includes a heating
element containing, as its main component, MoSi
2 that is pure MoSi
2 or MoSi
2 with increased electrical resistance by adding an insulating oxide, such as SiO
2, to MoSi
2 (normally, MoSi
2 is contained in an amount of 70 wt% or more).
[BACKGROUND ART]
[0003] Since a heating element containing molybdenum disilicide (MoSi
2) as its main component yields superior oxidation-resistant characteristics, it was
commercialized from around the 1950s as an ultrahigh temperature heating element for
use particularly in the atmosphere or under an oxidizing atmosphere, and is still
widely used today. This heating element contains, as its main component, MoSi
2 in an amount of 70 wt% or more.
[0004] Conventionally, with a heating element that is widely used in various fields such
as the glass industry and ceramic calcination, as shown in Fig. 8, the heat generating
part (normally, the "heat generating part" means the part (other than the terminal
part) having a narrow diameter which generates heat when applying current) has a shape
making a U (two-shank design), and is mounted in a manner of being suspended in midair
from the ceiling or side wall of the furnace, and the maximum allowable working temperature
of the furnace reaches 1700 to 1800°C.
[0005] Today, the standard of a commercially available U-shaped heater containing MoSi
2 as its main component is as follows; namely, the wire diameters of the heat generating
part and the terminal part are respectively, for example, ϕ3/ϕ6, ϕ4/ϕ9, ϕ6/ϕ12, ϕ9/ϕ18,
or ϕ12/ϕ24. This is because, with a MoSi
2 heater, since the heat generating part and the terminal part basically have the same
composition, it is necessary to control the amount of heat generation by changing
the electrical resistance based on the element wire diameter (cross-sectional area).
Accordingly, when current is applied to the heater, the high resistance part having
a narrow diameter becomes a high temperature and assumes the role as a heating unit,
and the low resistance part having a thick diameter suppresses heat generation and
assumes the role as a terminal part for keeping the feeding part to be a low temperature.
[0006] There are three modes of heat transfer; namely, heat conduction, heat convection,
and heat radiation, but it is said that the ratio of heat radiation from the heater
is high in the heat transfer to the object to be heat-treated in a resistance heating
furnace. The transmitted thermal energy Q of radiant energy is expressed with the
formula of Q = σ(T
14-T
24)•A•F. Here, 'σ' represents the Stefan-Boltzmann constant, and 'T
1' and 'T
2' represent the absolute temperature and correspond to the absolute temperature of
the heater and the object to be heat-treated in the resistance heating furnace. Furthermore,
'A' represents the area, and 'F' represents the view factor.
[0007] The view factor F is a numerical value representing the geometrical relation of two
surfaces, and represents a value obtained by sum of the proportions of the radiation
that is emitted from all positions on one surface and arrives at the other surface,
and is indicated as 0 to 1.
[0008] Accordingly, in order to increase the transmitted thermal energy Q of radiant energy
to the object to be heat-treated having the same surface area in a resistance heating
furnace, the absolute temperature of the heater needs to be increased, or the view
factor needs to be increased. Nevertheless, when the absolute temperature is increased,
more power will be required by that much, and there is no effect from the perspective
of energy saving.
[0009] Meanwhile, if it is possible to increase the ratio of radiation emitted from the
heater that reaches the object to be heat-treated; that is, if it is possible to increase
the view factor, effective heat transfer to the object to be heat-treated can be achieved
and energy saving will be achieved thereby.
[0010] Thus, the present inventors considered increasing the area of the heat generating
part facing the object to be heat-treated by changing the heat generating part from
a conventional rod-shaped (columnar shape) into a plate shape while maintaining the
cross-sectional area. If the ratio of the heat generating part line width/terminal
part line width is increased from the conventional "0.44 to 0.50" to "0.7 to 1.0",
the view factor should increase, and the transmitted thermal energy of radiant energy
should increase even with the same surface temperature of the heater. Thus, the present
inventors filed a patent application for this plate-shaped MoSi
2 heater. Nevertheless, when extruding a rod shape and thereafter heating and deforming
the rod shape into a plate shape (see Patent Document 1), it was extremely difficult
to achieve shape stability.
[0011] Furthermore, when extruding a belt shape (plate shape) from the beginning, the terminal
part would also become a plate shape, and because there is a need to review the structure
of the furnace and specially procure accessories to be used around the terminal part,
it was extremely inconvenient to replace the heating element from a conventional rod-shaped
heater.
[0012] Furthermore, with the method of extruding the heat generating part in a plate shape
and bonding it with a rod-shaped terminal part, there was a problem in that the welding
is unstable. Due to the foregoing circumstances, a heater demanded in recent years
is a heater that has superior shape stability, is free from problems of the welded
part, and can be easily replaced with an existing heater.
[0013] In order to enable the replacement with a conventional product without changing the
structure of the furnace or the accessories used around the heater, the terminal part
needs to maintain its conventional rod shape. Furthermore, the U-shaped pitch also
needs to be kept the same as the commercially available standard. Today, in a commercially
available heater in which the diameters of the heat generating part and the terminal
part are respectively ϕ4/ϕ9, ϕ6/ϕ12, or ϕ9/ϕ18, the standard U-shaped pitch of the
heat generating part is 25 mm (ϕ4 material), 40 mm (ϕ6 material), and 50 mm (ϕ9 material),
respectively.
[0014] When attempting to bend this part through electrical heating by using materials having
a thick terminal part; namely, 25 mm (ϕ9 material), 40 mm (ϕ12 material), and 50 mm
(ϕ18 material), conventionally the wire would break or, even if bent, the bent part
would become cracked and the processing was extremely difficult, and thus such processing
was not performed. Furthermore, even if it was possible to bend the material into
a U shape, it is difficult for the bent part to be placed on the same flat surface,
and if the heat generating part is ground as is, there will be variation in the thickness,
and it was difficult to produce a heater capable of uniform heat generation.
[0015] Accordingly, the Applicant filed a patent application for an improved invention (see
Patent Document 2). The foregoing points have been previously described in Patent
Document 2, but since they are problems that are also common in the present invention,
they have been once again described by way of precaution.
[0016] A U-shaped heater is produced by heating a MoSi
2 material to a high temperature to soften it, and thereafter bending it. Here, the
bent part is subject to compressive force at the inner part and tensile force at the
outer part, and the bent part is in a state with residual strain. This is particularly
notable when the diameter of the base material is thick and the U-shaped pitch is
narrow.
[0017] In the case of a heater that is produced by bending a MoSi
2, which has the same diameter as the terminal part, into a U shape, and grinding the
heat generating part into a plate shape, the foregoing production conditions will
apply, and it is likely that the bent part will have residual strain. And when the
heater is used in this kind of state, there are problems in that it is likely that
the bent part with residual strain will break, or the bent part will become warped
backward/forward, and this will considerably influence the life of the heater.
[0018] Furthermore, when the heat generating part is of a plate shape as described above,
it is configured to have a width that is substantially the same as the terminal part
in order to improve the radiation efficiency. Here, the inner part and the outer part
of the bent part will be subject to a distance difference in the current path (= difference
in resistance value). This will lead to a temperature difference between the inner
part and the outer part of the bent part. In other words, the temperature distribution
will be high at the inner part and low at the outer part, and the uniform heating
characteristics of the heater will deteriorate.
[0019] EP 2343951 discloses a ceramic heater (10) constructed by embedding a heat-generator (2) in
a base body (1) made of ceramics. The heat-generator (2) has a recess (5) in a surface
thereof, the ceramics being inside the recess (5). In light of the foregoing points,
the present inventors provide a further improved heating element comprising MoSi
2 and a method of producing such a heating element.
[CITATION LIST]
[PATENT DOCUMENTS]
[SUMMARY OF INVENTION]
[TECHNICAL PROBLEM]
[0021] The present invention is an integrated MoSi
2 based heating element in which the columnar terminal part and the plate-shaped heat
generating part are formed from the same material, and provides a U-shaped heater
(MoSi
2 based heating element), wherein a rod-shaped wire is bent in a U shape through electrical
heating, and thereafter subject to grinding, and only the straight part thereof is
used as the plate-shaped heat generating part. Accordingly, since the bent part is
not used as the heat generating part, the bent part will not generate heat, or the
generation of heat from the bent part can be suppressed, and it is thereby possible
to reduce the degradation of such part of the heater and obtain characteristics without
any temperature variation.
[SOLUTION TO PROBLEM]
[0022] In order to achieve the foregoing object, the present invention provides a U-shaped
heating element comprising MoSi
2 and a method for producing the same, as claimed.
[ADVANTAGEOUS EFFECTS OF INVENTION]
[0023] The present invention is a U-shaped MoSi
2 based heating element (heater), which comprises a columnar terminal part at each
end, a bent part, and a plate-shaped heat generating part connecting the columnar
terminal parts and the bent part, and can be used with higher efficiency in comparison
to conventional heaters. As evident from the above, the present invention provides
a flat heater in which the bent part is not ground to be flat, and only the straight
part of the U shape is ground and used as the heat generating part.
[0024] Accordingly, since the bent part is not subject to grinding, the bent part will not
generate heat, or the generation of heat from the bent part can be suppressed, and
it is thereby possible to reduce the degradation of such part of the heater and obtain
characteristics without any temperature variation.
[BRIEF DESCRIPTION OF DRAWINGS]
[0025]
[Fig. 1] This is a schematic diagram showing an example of a conventional integrated
MoSi2 plate-shaped heating element in which a columnar terminal part and a plate-shaped
heat generating part are formed from the same material, wherein the heat generating
part has a plate shape and the terminal part has a columnar shape.
[Fig. 2] This is a schematic diagram showing a representative example of the U-shaped
MoSi2 heating element of the present invention comprising a columnar terminal part at each
end, a bent part, and a plate-shaped heat generating part which connects the columnar
terminal parts and the bent part.
[Fig. 3] This is a schematic diagram of a U-shaped MoSi2 heating element having a columnar terminal part at each end, a bent part, and a plate-shaped
heat generating part which connects the columnar terminal parts and the bent part,
wherein the plate-shaped heat generating part which connects the columnar terminal
parts and the bent part has a plate width that is narrower than the diameter of the
columnar terminal part at each end.
[Fig. 4] This is a schematic diagram showing a representative example of a U-shaped
MoSi2 heating element having a columnar terminal part at each end, a bent part, and a plate-shaped
heat generating part which connects the columnar terminal parts and the bent part,
wherein both surfaces of the plate-shaped heat generating part which connects the
columnar terminal parts and the bent part have a flat surface (see cross-section views
- both the upper and lower surfaces in cross-section are flat).
[Fig. 5] This is a schematic diagram showing a representative example of a U-shaped
MoSi2 heating element having a columnar terminal part at each end, a bent part, and a plate-shaped
heat generating part which connects the columnar terminal parts and the bent part,
wherein both surfaces of the plate-shaped heat generating part which connects the
columnar terminal parts and the bent part have a flat surface (see cross-section views
- both the upper and lower surfaces in cross-section are flat), and the plate-shaped
heat generating part has a plate width that is narrower than the diameter of the columnar
terminal part at each end.
[Fig. 6] This is a photograph showing the electrical heating state of a conventional
MoSi2 plate-shaped heating element in which a columnar terminal part and a plate-shaped
heat generating part are formed from the same material, wherein the heat generating
part has a plate shape and the terminal part has a columnar shape.
[Fig. 7] This is a photograph showing the electrical heating state of the U-shaped
MoSi2 heating element of the present invention comprising a columnar terminal part at each
end, a bent part, and a plate-shaped heat generating part which connects the columnar
terminal parts and the bent part.
[Fig. 8] This is a schematic diagram showing a heat generating part and a terminal
part of a standard U-shaped heater.
[DESCRIPTION OF EMBODIMENTS]
[0026] In order to produce the MoSi
2 plate-shaped heating element of the present invention, foremost, a raw material powder
of the heating element is mixed with a binder, and the mixture is extruded from a
mold to obtain a columnar compact (green). Subsequently, after performing degreasing,
the raw material powder is sintered via primary sintering and electrical sintering,
and a columnar heating element base material, which is dense and yields favorable
straightness, is thereby prepared.
[0027] The structure of the columnar terminal part is the same as conventional products,
and an electrode part may be formed at the tip of the columnar terminal part at each
end. Accordingly, electricity can be supplied using commercially available accessories.
[0028] In this example, a raw material powder of the heating element is mixed with a binder,
and the mixture is extruded from a mold to obtain a columnar compact (green). Nevertheless,
it should be easy to understand that the method of producing the columnar compact
to be used as the raw material is not necessarily limited to the extrusion method
so as long as a columnar compact can be obtained. For example, a columnar compact
can also be obtained via press molding. Any raw material may be used so as long as
a precise sintered compact with high density can be obtained.
[0029] The thus prepared columnar heating element base material may be subject to electrical
heating and bent under a high temperature. After the columnar MoSi
2 heating element base material is bent into a U shape at a predetermined pitch, the
part (straight part of the U shape) between the columnar terminal part at each end
and the bent part, other than the columnar terminal part at each end and the bent
part, is subject to grinding to form the plate-shaped heat generating part. In other
words, the U-shaped MoSi
2 heating element of the present invention has a structure comprising 1) a columnar
terminal part at each end, 2) a bent part, and 3) a plate-shaped heat generating part
which connects the columnar terminal parts and (to) the bent part. Specifically, the
columnar terminal part is from the edge of the aluminum sprayed part to the end of
the inclined surface, the plate-shaped heat generating part is from the end of the
inclined surface of the columnar terminal part to the start of the inclined surface
of the bent part, and the bent part is from the start of the inclined surface of the
plate-shaped heat generating part on one side to the end of the inclined surface on
the other side.
[0030] Note that the plate-shaped heat generating part is not limited to a configuration
where both surfaces of the heat generating part have a flat surface, and also includes
a configuration where only one surface is a flat surface, and the other surface is
a curved surface (semicircular column shape).
[0031] Fig. 2 shows a MoSi
2 heating element in which only one surface, other than the lateral sides, of the plate-shaped
heat generating part which connects the columnar terminal parts and the bent part
has a flat surface. In other words, only one surface was subject to grinding. Since
the bent part of the MoSi
2 heating element was not subject to grinding and does not have a flat surface shape,
the cross-section area of the bent part becomes greater than the cross-section area
of the heat generating part, and the heat generation of this part is extremely small,
and only the plate-shaped heat generating part is the primary part that generates
heat. Thus, the degradation of the bent part is small and, consequently, characteristics
without any temperature variation can be obtained.
[0032] Incidentally, a conventional MoSi
2 heating element is shown in Fig. 1 for comparison. In Fig. 1, the bent part is also
subject to grinding and thereby has a flat shape. Thus, there are problems in that
the degradation of the bent part of a plate shape becomes severe, and a temperature
variation will arise.
[0033] Fig. 3 shows a MoSi
2 heating element in which one lateral side of the plate-shaped heat generating part
which connects the bent part and the columnar terminal parts is ground to have a plate
width that is narrower than the diameter of the columnar terminal at each end. In
the foregoing case, as with Fig. 2, only one surface, other than the lateral sides,
of the plate-shaped heat generating part which connects the bent part and the columnar
terminal parts has a flat surface, and the bent part was not subject to grinding and
does not have a flat surface shape. Therefore, the heat generation of this part is
extremely small, and only the plate-shaped heat generating part is the primary part
that generates heat. Thus, as with Fig. 2, the degradation of the bent part is small
and, consequently, characteristics without any temperature variation can be obtained.
[0034] Fig. 4 shows a MoSi
2 heating element in which both surfaces of the plate-shaped heat generating part which
connects the bent part and the columnar terminal parts have a planar surface (flat
surface). In the foregoing case also, as with Fig. 2, both surfaces, other than the
lateral sides, of the plate-shaped heat generating part which connects the bent part
and the columnar terminal parts have a flat surface, and the bent part was not subject
to grinding and does not have a flat surface shape. Therefore, the heat generation
of this part is extremely small, and only the plate-shaped heat generating part is
the primary part that generates heat. Thus, as with Fig. 2, the degradation of the
bent part is small and, consequently, characteristics without any temperature variation
can be obtained.
[0035] Fig. 5 shows a MoSi
2 heating element in which both lateral sides of the plate-shaped heat generating part
which connects the bent part and the columnar terminal parts are ground to have a
plate width that is narrower than the diameter of the columnar terminal part at each
end, and both surfaces of the plate-shaped heat generating part which connects the
bent part and the columnar terminal parts have a flat surface. In the foregoing case
also, as with Fig. 2, both surfaces, other than the lateral sides, of the plate-shaped
heat generating part which connects the bent part and the columnar terminal parts
have a flat surface, and the bent part was not subject to grinding and does not have
a flat surface shape. Therefore, this part does not generate heat, and the plate-shaped
heat generating part is the only part that generates heat. Thus, as with Fig. 2, the
degradation of the bent part is small and, consequently, characteristics without any
temperature variation can be obtained.
[0036] Furthermore, as needed, the part between the bent part and the plate-shaped heat
generating part, and the part between the plate-shaped heat generating part and the
columnar terminal part at each end, may be processed to be an inclined surface via
grinding. Consequently, the thermal gradient between the respective parts will become
moderate, and it is possible to yield the effect of alleviating the burden on the
heating element and extending the life of the heating element.
[EXAMPLES]
[0037] The Examples of the present invention are now explained. Note that these Examples
are provided for facilitating the understanding of the invention, and it should be
understood that the present invention is not limited to the ensuing Examples.
(Example 1)
[0038] A MoSi
2 powder and a SiO
2 powder were weighed at a ratio of 94:6 wt%, and mixed and pulverized with a pulverizer
to obtain an average grain size of 2 to 5 µm. A binder in an amount of 10 wt% was
added thereto, and mixed with a mixer. Subsequently, the mixture was molded into a
rod shape using an extruding machine, and this was thereafter subject to degreasing
and sintering under an argon atmosphere. This was removed from the furnace and subject
to electrical sintering in the atmosphere to obtain a rod material having a diameter
(ϕ) of 9 mm.
[0039] Subsequently, the obtained rod material was set in a U-shape bender, and heated to
1500 to 1550°C by applying current, and thereafter bent into a U shape having a pitch
of 25 mm. A straight part (40 mm), starting from a point that is 20 mm from the tip
of the bent part, was ground at a depth of 6.3 mm from one side, and the thickness
of that part was made to be 2.7 mm to form a heat generating part. Note that, based
on the foregoing grinding, the ratio of the cross-section area of the bent part and
the columnar terminal part (original rod material) and the cross-section area of the
heat generating part (ground part) was caused to be 4:1, but this ratio may also be
roughly 3:1. Furthermore, the boundary of the columnar terminal part and the heat
generating part was ground to have an inclined surface.
[0040] Finally, aluminum was thermally sprayed to the end of each columnar terminal part
to complete the product. Fig. 2 shows the structure of this Example. Fig. 7 shows
a state where current is supplied to the heater to generate heat. It is evident that,
as intended, the bent part is not generating heat.
(Example 2)
[0041] A rod material having a diameter (ϕ) of 9 mm which was produced in the same manner
as Example 1 was set in a U-shape bender, and heated to 1500 to 1550°C by applying
current, and thereafter bent into a U shape having a pitch of 25 mm. The inner side
and the outer side of the straight part were respectively ground, at a depth of 0.5
mm, at a length of 67 mm from the tip of the bent part. As a result of grinding both
of the inner side and the outer side, the relation of the width of the columnar terminal
part and the width of the heat generating part will be "columnar terminal part > heat
generating part". Furthermore, as a result of grinding both of the inner side and
the outer side, effects are yielded in that the edges of the heat generating part
in the width direction will not become an acute angle, and thus will not chip easily.
[0042] Subsequently, a straight part (40 mm), starting from a point that is 20 mm from the
tip of the bent part, was ground at a depth of 6.2 mm from one side, and the thickness
of that part was made to be 2.8 mm to form a heat generating part. Note that, based
on the foregoing grinding, the ratio of the cross-section area of the columnar terminal
part (original rod material) and the cross-section area of the heat generating part
(ground part) was caused to be 4:1, but this ratio may also be roughly 3:1. Furthermore,
the boundary of the columnar terminal part and the heat generating part was ground
to have an inclined surface. Finally, aluminum was thermally sprayed to the end of
each columnar terminal part to complete the product. Fig. 3 shows the structure of
this Example.
(Example 3)
[0043] A rod material having a diameter (ϕ) of 9 mm which was produced in the same manner
as Example 1 was set in a U-shape bender, and heated to 1500 to 1550°C by applying
current, and thereafter bent into a U shape having a pitch of 25 mm. A straight part
(40 mm), starting from a point that is 20 mm from the tip of the bent part, was ground
at a depth of 3.5 mm from both sides, and the thickness of that part was made to be
2.0 mm to form a heat generating part. Since grinding was performed from both sides
at the same depth, the width of the columnar terminal part and the width of the heat
generating part will be the same. Note that, based on the foregoing grinding, the
ratio of the cross-section area of the columnar terminal part (original rod material)
and the cross-section area of the heat generating part (ground part) was caused to
be 4:1, but this ratio may also be roughly 3:1. Furthermore, the boundary of the columnar
terminal part and the heat generating part was ground to have an inclined surface.
Finally, aluminum was thermally sprayed to the end of each columnar terminal part
to complete the product. Fig. 4 shows the structure of this Example.
(Example 4)
[0044] A rod material having a diameter (ϕ) of 9 mm which was produced in the same manner
as Example 1 was set in a U-shape bender, and heated to 1500 to 1550°C by applying
current, and thereafter bent into a U shape having a pitch of 25 mm. Only the outer
side of the U shape was ground, at a depth of 3.5 mm, at a length of 65 mm from the
tip of the bent part, and the width of the heat generating part was caused to be narrower
than the width of the columnar terminal part. Subsequently, a straight part (40 mm),
starting from a point that is 20 mm from the tip of the bent part, was ground at a
depth of 3.0 mm from both sides, and the thickness of that part was made to be 3.0
mm to form a heat generating part. Note that, based on the foregoing grinding, the
ratio of the cross-section area of the columnar terminal part (original rod material)
and the cross-section area of the heat generating part (ground part) was caused to
be 4:1, but this ratio may also be roughly 3:1. Furthermore, the boundary of the columnar
terminal part and the heat generating part was ground to have an inclined surface.
Finally, aluminum was thermally sprayed to the end of each columnar terminal part
to complete the product. Fig. 5 shows the structure of this Example.
(Comparative Example 1)
[0045] A rod material having a diameter (ϕ) of 9 mm which was produced in the same manner
as Example 1 was set in a U-shape bender, and heated to 1500 to 1550°C by applying
current, and thereafter bent into a U shape having a pitch of 25 mm. A part at a length
of 100 mm from the tip of the bent part was ground at a depth of 6.3 mm from one side,
and the thickness of that part was made to be 2.7 mm to form a heat generating part.
Since grinding is performed only from one side, the relation of the width of the columnar
terminal part and the width of the heat generating part will be "columnar terminal
part > heat generating part". Based on this grinding, the ratio of the cross-section
area of the columnar terminal part (original rod material) and the cross-section area
of the heat generating part (ground part) was caused to be 4:1. Furthermore, the boundary
of the columnar terminal part and the heat generating part was ground to have an inclined
surface.
[0046] Finally, aluminum was thermally sprayed to the end of each columnar terminal part
to complete the product. Fig. 1 shows the structure of this Comparative Example. Furthermore,
Fig. 6 shows a state where current is supplied to the heater to generate heat. Upon
comparing the bent part and the straight part, the tip of the bent part is dark. This
shows that the temperature of the tip of the bent part is low, and that there is a
temperature variation in the heat generating part. Furthermore, upon observing the
state of the heating element after heating it to a furnace temperature of 1500°C and
cooling it to room temperature, there was a problem in that the tip of the bent part
was warped toward the furnace side.
[INDUSTRIAL APPLICABILITY]
[0047] The present invention is a U-shaped MoSi
2 based heating element comprising a columnar terminal part at each end, a bent part,
and a plate-shaped heat generating part which connects the columnar terminal parts
and the bent part, wherein a cross-section area of the bent part is greater than a
cross-section area of the plate-shaped heat generating part. Furthermore, the present
invention is a method of producing a U-shaped MoSi
2 based heating element, wherein a columnar MoSi
2 raw material is bent into a U shape, and a straight part is ground, with a bent part
left unground, to have a flat surface, and used as the heat generating part.
[0048] As described above, with the present invention, since the bent part of the U-shaped
MoSi
2 based heating element is not ground, the bent part will not generate heat, or the
generation of heat from the bent part can be suppressed, and it is thereby possible
to reduce the degradation of such part of the heater, uniformly radiate and heat the
object to be heat-treated, and obtain characteristics without any temperature variation.
Accordingly, high temperature heating with low energy is enabled, and the present
invention is particularly useful as a heater for use in an electrical furnace or the
like.
[DESCRIPTION OF REFERENCE NUMERALS]
[0049]
- 1: Columnar terminal part
- 2: Plate-shaped heat generating part
- 3: Inclined surface formed via grinding
- 4: Bent part
- 5: Ground surface (flat surface)
- 6: Unground surface (columnar curved surface)
- 7: Structure capable of connecting to feeding part (aluminum sprayed part)
- 8: Lateral side grinding
[0050] When used in this specification and claims, the terms "comprises" and "comprising"
and variations thereof mean that the specified features, steps or integers are included.
The terms are not to be interpreted to exclude the presence of other features, steps
or components.
[0051] The features disclosed in the foregoing description, or the following claims, or
the accompanying drawings, expressed in their specific forms or in terms of a means
for performing the disclosed function, or a method or process for attaining the disclosed
result, as appropriate, may, separately, or in any combination of such features, be
utilised for realising the invention in diverse forms thereof. In particular, one
or more features in any of the embodiments described herein may be combined with one
or more features from any other embodiments described herein.
1. A U-shaped heating element comprising MoSi
2, the heating element comprising a columnar terminal part (1) at each end, a bent
part (4), and a plate-shaped heat generating part (2) which connects the columnar
terminal parts and the bent part, wherein:
a ratio of a cross-sectional area of the bent part to a cross-sectional area of the
plate-shaped heat generating part is at least 3:1; and
a ratio of a cross-sectional area of the columnar terminal parts to the cross-sectional
area of the plate-shaped heat generating part is also at least 3:1, thereby suppressing
heat generation in the bent part.
2. The heating element according to claim 1, wherein:
a ratio of a cross-sectional area of the bent part (4) to a cross-sectional area of
the plate-shaped heat generating part (2) is at least 4:1; and
a ratio of a cross-sectional area of the columnar terminal parts to the cross-sectional
area of the plate-shaped heat generating part is also at least 4:1.
3. The heating element according to claim 1 or 2, wherein the bent part (4) is of a columnar
shape.
4. The heating element according to claim 1, 2 or 3, wherein one or both surface(s) of
the plate-shaped heat generating part (2) comprise(s) a ground surface.
5. The heating element according to any one of claims 1 to 4, wherein a plate width of
the plate-shaped heat generating part (2) is smaller than a diameter of the columnar
terminal parts.
6. The heating element according to claim 5, wherein one lateral side of the plate-shaped
heat generating part (2) has a plate width that is narrower than the diameter of the
columnar terminal at each end.
7. The heating element according to claim 5, wherein both lateral sides of the plate-shaped
heat generating part (2) have a plate width that is narrower than the diameter of
the columnar terminal at each end.
8. The heating element according to any one of claims 1 to 7, wherein a part of the columnar
terminal (1) and/or a part of the bent part (4) comprises an inclined surface formed
via grinding.
9. The heating element according to claim 1, wherein:
the heating element is formed from a bent rod; and
the plate-shaped heat generating part (2) is formed in the bent rod by grinding; and
preferably the columnar terminal parts and bent part taper to the ground, plate-shaped
heat generating part.
10. A method of producing a U-shaped heating element comprising MoSi
2 according to any of claims 1 to 9, wherein a columnar MoSi
2 raw material is bent into a U shape and an area to become a heat generating part
(2) is thereafter ground, with a bent part left unground, to have a plate shape, wherein:
a ratio of a cross-sectional area of the bent part to a cross-sectional area of the
plate-shaped heat generating part is at least 3:1; and
a ratio of a cross-sectional area of the columnar terminal parts to the cross-sectional
area of the plate-shaped heat generating part is also at least 3:1, thereby suppressing
heat generation in the bent part.
11. The method of producing a heating element according to claim 10, wherein the unground
bent part is of a columnar shape.
12. The method of producing a heating element according to claim 10 or 11, wherein, in
the process of grinding the area to become the heat generating part (2) after bending
the columnar MoSi2 raw material into a U shape, grinding is started from one side of a curved surface
of a MoSi2 column, and the area is processed so that one surface of the plate-shaped heat generating
part have a flat surface and another surface of the plate-shaped heat generating part
remains to have a columnar curved surface.
13. The method of producing a heating element according to claim 10 or 11, wherein, in
the process of grinding the area to become the heat generating part (2) after bending
the columnar MoSi2 raw material into a U shape, both sides of a curved surface of a MoSi2 column are ground, and the area is processed so that both surfaces of the plate-shaped
heat generating part connecting the bent part and the columnar terminal parts have
a flat surface.
14. The method of producing a heating element according to any one of claims 10 to 13,
wherein one lateral side or both lateral sides of the plate-shaped heat generating
part (2) connecting the bent part and the columnar terminal parts are ground so as
to have a plate width that is narrower than a diameter of the columnar terminal part
at each end.
15. The method of producing a heating element according to any one of claims 10 to 14,
wherein a part between the bent part (4) and the plate-shaped heat generating part,
and a part between the plate-shaped heat generating part and the columnar terminal
part at each end, are processed into an inclined surface via grinding.
1. U-förmiges Heizelement, das MoSi
2, umfasst, wobei das Heizelement einen säulenartigen Anschlussteil (1) an jedem Ende,
einen gebogenen Teil (4) und einen plattenförmigen Wärme erzeugenden Teil (2) umfasst,
der die säulenartigen Teile und den gebogenen Teil verbindet, wobei:
ein Verhältnis einer Querschnittsfläche des gebogenen Teils zu einer Querschnittsfläche
des plattenförmigen Teils zumindest 3:1 ist; und
ein Verhältnis der Querschnittsfläche der säulenartigen Anschlussteile zur Querschnittsfläche
des plattenförmigen Wärme erzeugenden Teils ebenso zumindest 3:1 ist, um dadurch Wärmeerzeugung
im gebogenen Teil zu unterdrücken.
2. Heizelement nach Anspruch 1, wobei:
Ein Verhältnis einer Querschnittsfläche des gebogenen Teils (4) zu einer Querschnittsfläche
des plattenförmigen Teils (2) zumindest 4:1 ist; und
ein Verhältnis einer Querschnittsfläche der säulenartigen Anschlussteile zu einer
Querschnittsfläche des plattenförmigen Teils ebenso zumindest 4:1 ist.
3. Heizelement nach Anspruch 1 oder 2, wobei der gebogene Teil (4) einer säulenartigen
Form ist.
4. Heizelement nach Anspruch 1, 2 oder 3, wobei eine oder beide Oberfläche(n) des plattenförmigen
Wärme erzeugenden Teils (2) eine geschliffene Oberfläche umfasst/umfassen.
5. Heizelement nach einem der Ansprüche 1 bis 4, wobei eine Plattenbreite des plattenförmigen
Wärme erzeugenden Heizelements (2) kleiner als ein Durchmesser der säulenartigen Anschlussteile
ist.
6. Heizelement nach Anspruch 5, wobei eine laterale Seite des plattenförmigen Wärme erzeugenden
Teils (2) eine Plattenbreite aufweist, die schmaler als der Durchmesser des säulenartigen
Anschlusses an jedem Ende ist.
7. Heizelement nach Anspruch 5, wobei beide lateralen Seiten des plattenförmigen Wärme
erzeugenden Teils (2) eine Plattenbreite aufweisen, die schmaler als der Durchmesser
des säulenartigen Anschlusses an jedem Ende ist.
8. Heizelement nach einem der Ansprüche 1 bis 7, wobei ein Teil des säulenförmigen Anschlusses
(1) und/oder ein Teil des gebogenen Teils (4) eine geneigte Oberfläche umfasst, die
über Schleifen geformt ist.
9. Heizelement nach Anspruch 1, wobei:
Das Heizelement aus einer gebogenen Stange geformt ist; und
das plattenförmige Wärme erzeugende Teil (2) in der gebogenen Stange durch Schleifen
geformt ist; und sich die säulenartigen Anschlussteile und das gebogenen Teil vorzugsweise
zum geschliffenen, plattenförmigen Wärme erzeugenden Teil verjüngen.
10. Verfahren zur Herstellung eines U-förmigen MoSi
2 umfassenden Heizelements nach einem der Ansprüche 1 bis 9, wobei ein säulenartiges
MoSi
2-Rohmaterial in eine U-Form gebogen wird und eine Fläche, die ein Wärme erzeugendes
Teil (2) werden soll, wird danach geschliffen, wobei ein gebogener Teil ungeschliffen
gelassen wird, um eine Plattenform zu haben, wobei:
Ein Verhältnis einer Querschnittsfläche des gebogenen Teils zu einer Querschnittsfläche
des plattenförmigen Teils zumindest 3:1 ist; und
ein Verhältnis der Querschnittsfläche der säulenartigen Anschlussteile zur Querschnittsfläche
des plattenförmigen Wärme erzeugenden Teils ebenso zumindest 3:1 ist, um dadurch Wärmeerzeugung
im gebogenen Teil zu unterdrücken.
11. Verfahren zur Herstellung eines Heizelements nach Anspruch 10, wobei der ungeschliffene
gebogene Teil einer säulenartigen Form ist.
12. Verfahren zur Herstellung eines Heizelements nach Anspruch 10 oder 11, wobei, beim
Prozess des Schleifens der Fläche, die das Wärme erzeugende Teil (2) nach dem Biegen
des säulenartigen MoSi2-Rohmaterials in eine U-Form werden soll, der Schleifvorgang ab einer Seite einer
gekrümmten Oberfläche einer MoSi2-Säule gestartet wird, und die Fläche bearbeitet wird, sodass eine Oberfläche des
plattenförmigen Wärme erzeugenden Teils eine flache Oberfläche aufweist und eine andere
Oberfläche des plattenförmigen Wärme erzeugenden Teils verbleibt eine säulenartige,
gekrümmte Oberfläche aufzuweisen.
13. Verfahren zur Herstellung eines Heizelements nach Anspruch 10 oder 11, wobei, beim
Prozess des Schleifens der Fläche, die das Wärme erzeugende Teil (2) nach dem Biegen
des säulenartigen MoSi2-Rohmaterials in eine U-Form werden soll, beide Seiten einer gekrümmten Oberfläche
einer MoSi2-Säule geschliffen werden, und die Fläche bearbeitet wird, sodass beide Oberflächen
des plattenförmigen Wärme erzeugenden Teils das gebogene Teil verbinden und die säulenartigen
Anschlussteile eine flache Oberfläche aufweisen.
14. Verfahren zur Herstellung eines Heizelements nach einem der Ansprüche 10 bis 13, wobei
eine laterale Seite oder beide lateralen Seiten des plattenförmigen Wärme erzeugenden
Teils (2), welche das gebogene Teil und die säulenartigen Anschlussteile verbinden,
geschliffen sind, um eine Plattenbreite zu haben, die schmaler als ein Durchmesser
des säulenartigen Anschlussteils an jedem Ende ist.
15. Verfahren zur Herstellung eines Heizelements nach einem der Ansprüche 10 bis 14, wobei
ein Teil zwischen dem gebogenen Teil (4) und dem plattenförmigen Wärme erzeugenden
Teil, und einem Teil zwischen dem plattenförmigen Wärme erzeugenden Teil und dem säulenartigen
Anschlussteil an jedem Ende, über einen Schleifvorgang zu einer geneigten Oberfläche
bearbeitet sind.
1. Élément chauffant en U comprenant du MoSi
2, l'élément chauffant comprenant une partie terminale en forme de colonne (1) à chaque
extrémité, une partie cintrée (4) et une partie génératrice de chaleur en forme de
plaque (2) qui relie les parties terminales en forme de colonne et la partie cintrée,
dans lequel :
un rapport d'une zone transversale de la partie cintrée à une zone transversale de
la partie génératrice de chaleur en forme de plaque est au moins de 3:1 ; et
un rapport d'une zone transversale des parties terminales en forme de colonne à la
zone transversale de la partie génératrice de chaleur en forme de plaque est aussi
au moins de 3:1, supprimant ainsi la production de chaleur dans la partie cintrée.
2. Élément chauffant selon la revendication 1, dans lequel :
un rapport d'une zone transversale de la partie cintrée (4) à une zone transversale
de la partie génératrice de chaleur en forme de plaque (2) est au moins de 4:1 ; et
un rapport d'une zone transversale des parties terminales en forme de colonne à la
zone transversale de la partie génératrice de chaleur en forme de plaque est aussi
au moins de 4:1.
3. Élément chauffant selon la revendication 1 ou 2, dans lequel la partie cintrée (4)
est en forme de plaque.
4. Élément chauffant selon la revendication 1, 2 ou 3, dans lequel une surface ou les
deux surfaces de la partie génératrice de chaleur en forme de plaque (2) comprend
ou comprennent une surface meulée.
5. Élément chauffant selon l'une quelconque des revendications 1 à 4, dans lequel une
largeur de plaque de la partie génératrice de chaleur en forme de plaque (2) est plus
petite qu'un diamètre des parties terminales en forme de colonne.
6. Élément chauffant selon la revendication 5, dans lequel un côté latéral de la partie
génératrice de chaleur en forme de plaque (2) a une largeur de plaque qui est plus
étroite que le diamètre de la partie terminale en forme de colonne à chaque extrémité.
7. Élément chauffant selon la revendication 5, dans lequel les deux côtés latéraux de
la partie génératrice de chaleur en forme de plaque (2) ont une largeur de plaque
qui est plus étroite que le diamètre de la partie terminale en forme de colonne à
chaque extrémité.
8. Élément chauffant selon l'une quelconque des revendications 1 à 7, dans lequel une
partie de la partie terminale en forme de colonne (1) et/ou une partie de la partie
cintrée (4) comprend une surface inclinée formée par meulage.
9. Élément chauffant selon la revendication 1, dans lequel :
l'élément chauffant est formé à partir d'une tige cintrée ; et
la partie génératrice de chaleur en forme de plaque (2) est formée à partir de la
tige cintrée par meulage ; et
de préférence, les parties terminales en forme de colonne et la partie cintrée s'effilent
vers la partie génératrice de chaleur en forme de plaque, meulée.
10. Procédé de fabrication d'un élément chauffant en U comprenant du MoSi
2 selon l'une quelconque des revendications 1 à 9, dans lequel une matière première
de MoSi
2 en forme de colonne est cintrée en forme de U et une zone qui va devenir une partie
génératrice de chaleur (2) est ensuite meulée, avec une partie cintrée laissée non
meulée, pour avoir une forme de plaque, dans lequel :
un rapport d'une zone transversale de la partie cintrée à une zone transversale de
la partie génératrice de chaleur en forme de plaque est de 3:1 ; et
un rapport d'une zone transversale des parties terminales en forme de colonne à la
zone transversale de la partie génératrice de chaleur en forme de plaque est aussi
au moins de 3:1, supprimant ainsi la production de chaleur dans la partie cintrée.
11. Procédé de fabrication d'un élément chauffant selon la revendication 10, dans lequel
la partie cintrée, non meulée, est en forme de plaque.
12. Procédé de fabrication d'un élément chauffant selon la revendication 10 ou 11, dans
lequel, dans le processus de meulage de la zone qui va devenir la partie génératrice
de chaleur (2) après le cintrage de la matière première de MoSi2 en forme de colonne en forme de U, le meulage est commencé d'un côté d'une surface
incurvée d'une colonne de MoSi2, et la zone est traitée de telle sorte qu'une surface de la partie génératrice de
chaleur en forme de plaque a une surface plate et une autre surface de la partie génératrice
de chaleur en forme de plaque reste pour avoir une surface en forme de colonne, incurvée.
13. Procédé de fabrication d'un élément chauffant selon la revendication 10 ou 11, dans
lequel, dans le processus de meulage de la zone qui va devenir la partie génératrice
de chaleur (2) après le cintrage de la matière première de MoSi2 en forme de colonne en forme de U, les deux côtés d'une surface incurvée d'une colonne
de MoSi2 sont meulés, et la zone est traitée de telle sorte que les deux surfaces de la partie
génératrice de chaleur en forme de plaque reliant la partie cintrée et les parties
terminales en forme de colonne ont une surface plate.
14. Procédé de fabrication d'un élément chauffant selon l'une quelconque des revendications
10 à 13, dans lequel un côté latéral ou les deux côtés latéraux de la partie génératrice
de chaleur en forme de plaque (2) reliant la partie cintrée et les parties terminales
en forme de colonne sont meulés de façon à avoir une largeur de plaque qui est plus
étroite qu'un diamètre de la partie terminale en forme de colonne à chaque extrémité.
15. Procédé de fabrication d'un élément chauffant selon l'une quelconque des revendications
10 à 14, dans lequel une partie entre la partie cintrée (4) et la partie génératrice
de chaleur en forme de plaque, et une partie entre la partie génératrice de chaleur
en forme de plaque et la partie terminale en forme de colonne à chaque extrémité,
sont traitées en une surface inclinée par meulage.