U.S. patent number RE29,332 [Application Number 05/526,895] was granted by the patent office on 1977-08-02 for pipe heat transfer assembly and method of making same.
This patent grant is currently assigned to Thermon Manufacturing Company. Invention is credited to James E. Bilbro, Ben C. Johnson, Jr..
United States Patent |
RE29,332 |
Bilbro , et al. |
August 2, 1977 |
Pipe heat transfer assembly and method of making same
Abstract
Pipe heat transfer assembly and method of making same, wherein a
strip of heat transfer material is pre-shaped to a solid flexible
form for closely .[.comforming.]. .Iadd.conforming .Iaddend.with a
heat transfer element for either heating or cooling and which is
also pre-shaped to fit closely within an external channel member,
whereby the entire assembly may be more easily and rapidly
installed with unskilled labor in the field on a pipe to be heated
or cooled, using retaining band means as the holding means for the
assembly, with the assurance of complete coverage of the heat
transfer element by said heat transfer material so as to eliminate
air gaps. The heat transfer material may be pre-shaped by molding
or extruding, with the heat transfer element embedded therein
during such pre-shaping, or with a preformed space for the heat
transfer element. The heat transfer material is solid, capable of
retaining its shape, and remains flexible, after pre-shaping,
within the normal temperature range to which the material is
subjected, preferably within a range of from about 10.degree. F. to
about 120.degree. F.
Inventors: |
Bilbro; James E. (Whitman
County, WA), Johnson, Jr.; Ben C. (Comal County, TX) |
Assignee: |
Thermon Manufacturing Company
(N/A)
|
Family
ID: |
27004941 |
Appl.
No.: |
05/526,895 |
Filed: |
November 18, 1974 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
370396 |
Jun 15, 1973 |
03834458 |
Sep 10, 1974 |
|
|
Current U.S.
Class: |
165/164;
165/DIG.442; 29/890.045; 138/103; 138/111; 156/199; 165/180;
165/185; 219/535; 264/271.1; 264/279; 392/468; 392/480 |
Current CPC
Class: |
B23P
15/26 (20130101); H05B 3/54 (20130101); H05B
3/56 (20130101); H05B 3/565 (20130101); Y10T
29/49377 (20150115); Y10T 156/1007 (20150115) |
Current International
Class: |
B23P
15/26 (20060101); H05B 3/58 (20060101); H05B
3/54 (20060101); B23P 015/26 () |
Field of
Search: |
;219/535 ;138/111,112
;165/164 ;264/174,271,279 ;156/209,199,196 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,600,601 |
|
Apr 1970 |
|
DT |
|
29,490 |
|
Nov 1917 |
|
NO |
|
Primary Examiner: Davis, Jr.; Albert W.
Assistant Examiner: Richter; Sheldon
Attorney, Agent or Firm: Pravel, Wilson & Gambrell
Claims
We claim:
1. A method of making a pipe heat transfer assembly adapted for
mounting on a pipe or the like having a channel member with heat
transfer material and a heat transfer element in the channel
member, the improvement comprising the steps of:
preshaping heat transfer material to a solid flexible
shape-retaining elongated strip prior to mounting said heat
transfer material on a pipe or the like;
embedding a heat transfer element in said heat transfer material
prior to mounting said heat transfer material on such pipe or the
like; and,
said preshaping including shaping the external surface of said
strip to closely conform to the interior of the channel member and
to such pipe or the like to which the assembly is to be
applied.
2. The method set forth in claim 1, wherein said embedding includes
the steps of:
preforming said heat transfer material with a cavity for said heat
transfer element; and
inserting said heat transfer element into said cavity after the
preforming thereof.
3. The method set forth in claim 1, wherein said heating element
includes:
a plurality of electric resistance heating wires extending
longitudinally of the strip and completely surrounded by said heat
transfer material.
4. The method set forth in claim 1, wherein said heating element
includes:
a tube for a heat transfer fluid to flow therethrough.
5. The method set forth in claim 1, wherein:
said heat transfer material, after said preshaping, remains
flexible without any significant flow within a temperature range of
from about 10.degree. F. to about 120.degree. F.
6. The method set forth in claim 1, including:
positioning the channel member over said preshaped heat transfer
material with the heat transfer element therewith; mounting said
pipe heat transfer assembly on such pipe or the like; and
thereafter placing clamping bands around the channel member and
such pipe or the like on which the assembly is disposed to secure
the assembly to the pipe.
7. The method set forth in claim 1, wherein:
said heat transfer element is embedded in said heat transfer
material during the preshaping thereof. .Iadd. 8. A method of
making a pipe heat transfer assembly adapted for mounting on a pipe
or the like having a channel member with heat transfer material and
a heat transfer element in the channel material, the improvement
comprising the steps of:
preshaping heat transfer material to a solid, flexible
shape-retaining elongated strip prior to mounting said heat
transfer material on a pipe or the like;
preforming said heat transfer material with a cavity for a heat
transfer element;
inserting said heat transfer element into said cavity after the
preforming thereof; and
said preshaping including shaping the external surface of said
strip to closely conform to the interior of the channel member and
to said pipe or
the like..Iaddend..Iadd. 9. The method set forth in claim 8,
wherein said heating element includes:
a tube for a heat transfer fluid to flow
therethrough..Iaddend..Iadd. 10. A method of insulating a heat
transfer element which is mounted on a pipe or the like for more
effective heating or cooling of said pipe, comprising the steps
of:
preshaping heat transfer material to a solid shape-retaining
elongated strip having a preformed space conforming to the shape of
a heat transfer element;
preshaping the external surface of said strip to conform to the
interior of a channel member;
mounting said preshaped heat transfer material over said heat
transfer element so that said heat transfer element is positioned
in said preformed space; and
positioning said channel member over said heat transfer
material..Iaddend..Iadd. 11. A method of making a heat transfer
assembly adapted for mounting on a pipe or the like having a
channel member with heat transfer material and a heat transfer
element in the channel member, the improvement comprising the steps
of:
preshaping heat transfer material to a solid, flexible
shape-retaining elongated strip prior to mounting said heat
transfer material on a pipe or the like;
embedding a heat transfer element in said heat transfer material;
and
said preshaping including shaping the external surface of said
strip to closely conform to the interior of the channel member and
to said pipe or the like..Iaddend.
Description
BACKGROUND OF THE INVENTION
The field of this invention is heat transfer apparatus and methods,
particularly for heating or cooling from a heat transfer element
disposed externally on a pipe. The term "pipe" as used herein
includes tubes, conduits or other members, the contents of which is
to be heated or cooled by the heat transfer element.
U.S. Pat. No. 3,331,946 discloses a heat transfer assembly wherein
the heat transfer material was placed in a channel member in a
putty-like or plastic state. This was accomplished by pressing the
channel member or applicator downwardly on top of the heat transfer
material with the heat transfer element embedded therein. Although
the objective was to eliminate undesirable air gaps in the heat
transfer material and between the heat transfer element and the
heat transfer material, it has been found that the efficiency and
success depends upon the personnel handling the putty-like
material, and therefore, the elimination of air gaps has been
difficult and not dependable.
SUMMARY OF THE INVENTION
The present invention relates to new and improved heat transfer
assembly and method of making same, wherein the elimination of air
gaps is more positively accomplished, and errors due to personnel
are more easily avoided. The heat transfer material, instead of
being applied in a putty-like form in a channel is pre-shaped, by
molding or extruding, usually with the heat transfer element
embedded therein, or shaped with a cavity to closely conform to the
heat transfer element. The heat transfer material is also
pre-shaped externally to closely conform to the internal area of
the channel member which is applied over the heat transfer material
and element at the job site where the pipe to be heated or cooled
is located. The invention further eliminates either the on the job
site handling of the putty-like heat transfer material or the
shipping of the channel members prefabricated with the heat
transfer material and element, thereby facilitating shipping and
handling as compared to the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a horizontal sectional view illustrating one embodiment
of the pre-shaped and pre-formed heat transfer material with a heat
transfer element embedded therein;
FIG. 2 is a view illustrating the pre-shaped and pre-formed heat
transfer material and heating element confined by a channel member
with clamping straps holding the assembly on a pipe for heat
transfer purposes;
FIG. 3 is a vertical sectional view taken on line 3--3 of FIG. 2;
and
FIG. 4 is a vertical sectional view similar to that of FIG. 3, but
illustrating a modified form of the invention, wherein the channel
member and the components thereof are formed in a different shape
from that of FIG. 3 to illustrate that the invention is not limited
to any particular shape, and further showing a fluid conducting
tube as the heat transfer element rather than the electrical
resistance element of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to a pipe heat transfer assembly
generally designated with the letter A (FIG. 2) which is adapted to
be mounted upon a pipe P. The term "pipe" is defined above and is
intended to include various types of conductors or members for heat
transfer purposes. Briefly, the heat transfer assembly includes a
pre-shaped heat transfer material strip H, a heat transfer element
E, a channel member C, and clamping members M for securing the
assembly on the pipe P.
Considering the invention more in detail, the heat transfer
material H is either extruded or molded, using a material which is
capable of being preshaped, but which becomes solid and flexible
and remains in such solid, flexible state so as to retain its
preshaped form. The external shape of the heat transfer material H
conforms to and preferably is identical with the cavity or recess
10 formed in the channel member C, and also the portion of the pipe
P designated 11 (FIG. 3) which is defined by the channel member C.
Since the heat transfer material H is flexible and resilient, it
will be understood that the exact configuration of the external
surface of the heat transfer material H does not have to be
identical to the surfaces of the channel member C defining the
internal recess or cavity 10 and the external pipe portion 11 since
the material may yield and assume such shape after being confined
on the pipe P by the channel member C. In any event, the heat
transfer material H does have a cross-sectional shape which
generally is substantially the same as that defined by the internal
cavity or recess 10 of the channel member 10 and the pipe portion
11 so as to substantially fill such area without any air gaps or
spaces therebetween.
It is also important to note that the extruding or molding of the
heat transfer material H may be accomplished at a point remote from
the field application of such heat transfer material H to the pipe
P so that the material may be extruded or molded under enough
pressure and force to assure that air pockets or bubbles or gaps
within the material H are virtually eliminated from the strip of
material H. This is a decided advantage over the application of the
heat transfer material H in a putty-like or plastic form as in the
prior art.
In the normal use of the present invention, the heat transfer
element E is an electrical resistance wire 15 (FIG. 1) which is
connected by any suitable means to an electrical terminal 16 and a
lead-in wire 17, leading to a source of electrical power. The heat
is provided by the element E in the known manner of electrical
resistance heaters and such heat is transferred through the heat
transfer material H to the pipe P which has a liquid or other
material therein which is to be heated or maintained in a heated
condition by the heat from the heat transfer element E.
Preferably, the heat transfer element E is passed through the
extruder during the extruding of the heat transfer material H so
that the material H and the element E are molded or are extruded as
a unit as illustrated in FIG. 1. This provides for the assurance
that the element E is embedded in the heat transfer material H so
that air spaces or pockets around the heat transfer element E is
avoided.
At this point, it should be noted that the heat transfer element E
is not limited to an electrical resistance heater element such as
shown in FIGS. 1-3, and therefore, a modified form of the invention
is shown in FIG. 4, wherein a heat transfer element E-1 is disposed
within heat transfer material H-1 which in turn is confined by a
modified channel member C-1.
In such modified form of the invention illustrated in FIG. 4, the
heat transfer material strip H-1 has the same general appearance as
the strip H, except that the material strip H-1 is molded or
extruded with a recess or cavity 20 therein for receiving the heat
transfer element E-1, or any other heat transfer element such as
the heat transfer element E. The recess or cavity 20 is
predetermined so that when the heat transfer material H-1 is
assembled with the heat transfer element E-1 or E, the material H-1
closely conforms to and effectively embeds the heat transfer
element within the heat transfer material.
It should also be noted that although the heat transfer element E-1
is shown as being inserted from the bottom of the strip H-1 through
a longitudinal space 20a for receiving the element E-1 in the
recess or cavity, the material H-1 may be molded or extruded so
that the heat transfer element E-1 or E is inserted longitudinally,
thereby providing some of the heat transfer material between the
element E-1 or E and the external surface of the pipe P.
The channel member C-1 has been shown with a different shape from
the channel member C to illustrate that the invention is not
limited to any particular shape of channel member or any particular
external shape of the heat transfer material H or H-1. The channel
members C and C-1 are preferably formed of metal or any other
relatively strong material capable of confining the heat transfer
material and also retaining its position on the pipe P.
For the purposes of holding the entire assembly A on the pipe P,
the assembly includes the clamping bands M which are preferably of
any conventional type such as steel bands 25 which extend around
the pipe P and the channel member C or C-1 and which are affixed by
bending a connector 26 to the ends of the band 25, as is well
known. Any other clamping arrangement may be utilized so long as it
retains the channel member C, the heat transfer material H and the
heating element E, or the alternate form shown in FIG. 4, on the
pipe P in the selected position.
It should also be understood that the two clamping members M
illustrated are for illustration purposes only and a plurality of
such members M may be employed, depending upon the length of the
channel member C or C-1 which is being used. Also, it should be
understood that more than one channel member may be employed with
each of the strips H, or alternatively, more than one of the strips
H may be employed with a single channel member.
Although the invention is illustrated with the electrical
resistance heating element E for heating purposes, the modification
shown in FIG. 4 illustrates the heat transfer element E-1 which may
be used for either heating or cooling by passing the appropriate
fluid therethrough.
Although the invention is not limited to any particular heat
transfer material, by way of example, the strip H or H-1 may be
formed of a material having the following general formula:
______________________________________ Thermoplastic Binder 10% -
80% (by weight) Graphite (or other heat- conducting material) 20% -
90% ______________________________________
The thermoplastic binders which may be used may be those in the
broad classification of rubbers, such as butyl rubber, silicone
rubber, nitrile, polyurethane, and acrylic resins. Also, the
thermoplastic materials could include the polyamides and the
polyamide copolymers, as well as the fluoroplastics, the
polyethylenes and the polysulfides.
The thermoplastic material would have a softening point of about
95.degree. C. and a specific gravity of about 0.97. In any event,
the heat transfer material in the strip H or H-1 would retain its
shape and would not flow during exposure to the normal temperature
range from about 10.degree. F. to about 120.degree. F. Also, the
material remains flexible within such temperature range.
In the preferred embodiment of this invention, the heat transfer
material in either the strip H or the strip H-1 has the following
composition:
______________________________________ Polyamide Resin 35% - 45%
(by weight) softening point 160.degree. - 170.degree. C. specific
gravity 0.98 N-ethyl-o and p-Toluenesulfonamides 9% - 11% Graphite
(or other heat-conducting material) 40% - 50% Paraffin wax (melting
point 180.degree.-190.degree. F.) 4% - 6%
______________________________________
All of the above percentages are by weight. In the foregoing
example, the percentages are set forth as a range, but a specific
product may have 40% of the polyamide resin, 10% of the
sulfonamides, 45% of the graphite and 5% of the wax.
It should be understood that the foregoing are merely set forth by
way of example and not by way of limitation.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape, and materials as well as in the details of the
illustrated construction may be made without departing from the
spirit of the invention.
* * * * *