U.S. patent number 3,730,373 [Application Number 05/239,593] was granted by the patent office on 1973-05-01 for band-type electric heaters.
This patent grant is currently assigned to Emerson Electric Co.. Invention is credited to Lloyd S. Kozbelt.
United States Patent |
3,730,373 |
Kozbelt |
May 1, 1973 |
BAND-TYPE ELECTRIC HEATERS
Abstract
A band-type electric heater adapted to be secured around the
periphery of a cylindrical object to be heated, comprising an
elongated metal-sheathed electric heater bent longitudinally to
arcuate shape so that an inner surface follows the curvature of the
object, and a flexible metal clamping band adapted to encompass the
object and overlie the outer surface of the heater, and having
means to draw it tightly around the object and thereby press the
heater inner surface against the periphery of the object. The band
has embossments which engage the heater outer surface and limit
surface-to-surface contact between the band and the heater, to
thereby reduce the amount of heat conducted to the band, and to
also reduce frictional contact between the band and the heater to
permit the two to move relatively and adjust to conform to good
heating relationship with the object at the time the band is drawn
tightly around the object.
Inventors: |
Kozbelt; Lloyd S. (Pittsburgh,
PA) |
Assignee: |
Emerson Electric Co. (St.
Louis, MO)
|
Family
ID: |
22902844 |
Appl.
No.: |
05/239,593 |
Filed: |
March 30, 1972 |
Current U.S.
Class: |
219/535;
219/530 |
Current CPC
Class: |
H05B
3/565 (20130101); H05B 3/56 (20130101) |
Current International
Class: |
H05B
3/58 (20060101); H05B 3/54 (20060101); H05b
003/58 () |
Field of
Search: |
;219/301,530,535,536,540
;165/135 ;13/20,22,25,31 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Mayewsky; Volodymyr Y.
Claims
I claim:
1. A band-type electric heater adapted to be secured around the
periphery of a cylindrical object to be heated, comprising:
a pair of elongated metal-sheathed electric heaters, each bent
longitudinally to an arcuate shape so that an inner surface follows
the curvature of said object, each heater having a terminal at its
opposite ends which extends transversely from the outer surface of
the same,
and a split, flexible metal clamping band adapted to encompass said
object and means at the split to draw the band tightly around said
object,
said band comprising a central strap, a pair of jumper straps, each
having an end connected to an end of said central strap and each
having an elongated opening therein, and a pair of end straps, each
having an end connected to the opposite end of a jumper strap and
having means at its opposite end to receive a part of the means to
draw said band tightly around said object,
in assembly, said heaters being disposed in end-to-end relation
within said band with pairs of facing ends in alignment with
respective jumper straps and with terminals at facing ends
extending freely through an opening in a jumper strap, and with
said central strap, said jumper strap and said end straps overlying
and pressing against the outer surface of each heater to press the
inner surface of the same against the periphery of said object when
said band is drawn tightly around the latter,
said central strap having embossments which engage the adjoining
outer surface of at least oneheater and limit surface-to-surface
contact therebetween,thereby reducing the amount of heat conducted
to said band, and also reducing the frictional contact between said
central strap and the heater to permit the same to move relatively
and adjust to conform to good heating relationship with said object
at the time the band is drawn tightly around said object.
2. The construction according to claim 1 and further including at
least one embossment in said end straps to perform the same
function as the embossments in said central strap.
3. The construction according to claim 2 wherein said end straps
are considerably shorter than said central strap, and each end
strap has a single embossment formed therein.
Description
BACKGROUND AND SUMMARY
Band-type heaters of the general construction herein disclosed are
known in the prior art, and a good example is found in U. S. Pat.
No. 2 545 653. In this patent, the band has full contact with the
heater and as a result considerable heat is transmitted to the
band. This is objectionable not only because of heat loss butalso
because the highly heated band may be dangerous to certain things
in its environment. Full contact of the band with the heater is
also objectionable because the high frictional contact sometimes
prevents relative movement therebetween and hinders adjustment of
the parts to conform to good heating relationship with the object
to be heated at the time the band is drawn tightly around the
object.
I have discovered that by forming embossments in the band to limit
surface-to-surface contact between the band and the heater, the
foregoing disadvantages are eliminated without sacrificing any of
the desirable features of band-type heaters.
DESCRIPTION OF THE DRAWINGS
In the drawings accompanying this description and forming a part of
this specification, there is shown, for purpose of illustration, an
embodiment which my invention may assume, and in these
drawings:
FIG. 1 is a face view of a band-type electric heater, which is
clamped around a cylindrical object,
FIG. 2 is a side view of the heater shown in FIG. 1,
FIG. 3 is a perspective view of one of two similar metal-sheathed
electric heaters forming part of the assembly shown in FIG. 1 and
2,
FIG. 4 is a plan view of the clamping band, prior to bending it to
circular shape,
FIG. 5 is an edge view of the band shown in FIG. 4,
FIG. 6 is an enlarged, fragmentary sectional view corresponding to
the line 6--6 of FIG. 1,
FIG. 7 is a fragmentary sectional view corresponding to the line
7--7 of FIG. 6, and
FIGS. 8 through 10 are fragmentary plan views of the clamping band,
showing various forms of embossments.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The band-type heater is adapted to be secured around a cylindrical
object O which may be an extrusion nozzle, a water tank, or the
like. The heater comprises two similar metal-sheathed electric
heating elements 15,15 of any suitable type. In the presently
disclosed embodiment, the elements are of the so-called "mica
heater" type wherein a resistance wire or ribbon 16 is wound to
sinuous form and disposed between layers 17 of mica, the assembly
being contained within a metal sheath 18 of rectangular
cross-section, as seen in FIG. 6, which was originally of trough
form, the legs of the trough being bent inwardly over a closure
plate 19. The bottom of the trough forms the inner surface 20 of
the heater, and the closure plate 19 forms the heater outer
surface. The heating element 15 has terminals 22 at opposite ends,
and each terminal extends transversely from the heater outer
surface 19 and is adapted to be connected in circuit with a power
source. The terminals 22, in accordance with usual practice, are
electrically connected to opposite ends of the resistor wire 16
within the heating element. Instead of mica insulation, the
insulating material may be of any other suitable form. Each heater
15 is elongated and bent longitudinally to an arcuate shape so that
the inner surface 20 follows the curvature of the periphery of the
object O.
The clamping band 23 is made of flexible metal strip, such as
stainless steel, and is of the split band type with means at the
split for drawing the band tightly around the object O and thus in
turn press the electric heaters into engagement with the peripheral
surface of the object O.
Asbest seen in FIGS. 4 and 5, the clamping band comprises a central
strap 24, a pair of jumper straps 25,25 and a pair of end straps
26,26. The straps may be of the same gauge strip and the central
strap 24 and end straps 26,26 may be of the same width, as seen in
FIG. 4. The jumper straps 25,25 are preferably wider, and each is
formed with a relatively large and elongated opening 27.
One end of each jumper strap 25 is connected to an end of the
central strap 24, as by spot welds 30. The opposite end of each
jumper strap 25 is connected to an end of an end strap 26, as by
spot welds 31. The opposite end of each end strap 26 is doubled
over and spot welded as shown at 32, to form a loop 33. The loops
33 contain barrel nuts 34 (FIG. 1) through which is threaded a
clamping bolt 35.
In the assembly, the two electric heaters are disposed in
end-to-end relation within the band 23, as seen in FIG. 1, with the
facing ends in alignment with the jumper straps 25 so that the
terminals 22,22 at such facing ends freely project through the
openings 27 in respective jumper straps 25, as see in FIG. 2.
The central strap 24 is formed with a plurality of embossments
which, as shown in FIG. 4, are circular depressions 36 arranged in
staggered relation. The embossments engage the outer surface 19 of
the lower heater 15, as seen in FIG. 1, and limit
surface-to-surface contact between the central strap 24 and the
heater outer surface 19 to thereby reduce the amount of heat
conducted to the clamping band and to also reduce the frictional
contact between the central strap and the heater to permit the same
to move relatively and adjust to conform to good heating
relationship with the object O at the time the clamping band is
drawn tightly around the object. Again referring to FIG. 4, it will
be noted that each end band has a single embossment 37 and these
function in the same manner as the embossments 36.
The embossments in the central strap 23 may be arranged in single
file, as shown at 36a in FIG. 8, or in spaced pairs as shown at 36b
in FIG. 9. Further, the embossments may be elongated and extend
transversely of the central strap 23, as shown at 37c in FIG.
10.
* * * * *