Note: Descriptions are shown in the official language in which they were submitted.
CA 02822253 2013-07-30
METHOD FOR PROVIDING A THREADED FITTING IN A WATER
TANK HEADER, HEADER PRODUCED BY THE METHOD
AND WATER TANK INCLUDING THE HEADER
BACKGROUND
The construction of water heaters typically involves the connection, by
welding, of a pair of
headers to a cylindrical wall, to form a tank. For the delivery of water into
the tank, and the
withdrawal of water therefrom, threaded pressure vessel connections are
typically provided as
part of the headers. The headers are typically each defined by a stamped body
and, for each
threaded fitting, a flanged threaded fitting which is welded to the body.
SUMMARY
Forming one aspect of the invention is a method for producing a header from a
steel blank, the
header having a boss and being of the type that is welded in use to a
cylindrical wall to produce
a tank subassembly, the boss being interiorly threaded to define a threaded
pressure vessel
connection, the method comprising the steps of: extruding the boss in the
steel blank; and
tapping the thread.
According to another aspect of the invention, the extrusion of the boss can be
carried out with
an extrusion punch and extrusion die.
According to another aspect of the invention, the extrusion can involve
passage of the extrusion
punch through a preformed hole in the blank into the extrusion die.
According to another aspect of the invention, the extrusion punch can be about
a 0.960"
extrusion punch, the preformed hole can be about a 5/16" hole and the steel
blank can be about
0.135" thickness HRPO draw quality steel.
According to another aspect of the invention, the extrusion punch can be a
0.960" extrusion
punch, the preformed hole can be a 5/16" hole and the steel blank can be a
0.135" thickness
HRPO draw quality steel.
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According to another aspect of the invention, the extrusion punch can travel
at about 480 inches
per minute as the boss is formed.
According to another aspect of the invention, the extrusion punch can have a
TD coating.
According to another aspect of the invention, the extrusion punch can be
lubricated with
Syndraw 99 lubricant.
A header produced according to the inventive method forms another aspect of
the invention.
Forming yet another aspect of the invention is an improved water heater. The
water heater is of
the type comprising: a cylindrical wall and a pair of headers welded to the
wall to form a tank;
and a heating element coupled to the tank and adapted to heat the contents
thereof. The
improvement comprises: a header member, produced according to the inventive
method,
defining at least one of the pair of headers.
Other advantages, features and characteristics of the present invention will
become more
apparent upon consideration of the following detailed description of an
exemplary embodiment
of the invention and the appended claims with reference to the accompanying
drawings, the
latter being briefly described hereinbelow.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a prior art water heater tank;
FIG. 2 is a perspective view of an extrusion punch used in the
exemplary embodiment
of the invention;
FIG. 3 is an end view of the structure of FIG. 2;
FIG. 4 is a side view of the structure of FIG. 2;
FIG. 5 is a view along 5-5 of FIG. 3;
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FIG. 6 is a perspective view of an extrusion die used in the
exemplary embodiment;
FIG. 7 is an end view of the structure of FIG. 6;
FIG. 8 is a side view of the structure of FIG. 6;
FIG. 9 is a view along section 9-9 of FIG. 7; and
FIG. 10 is a view similar to FIG. 1 showing the construction of a
water heater according to
the exemplary embodiment of the invention.
DETAILED DESCRIPTION
A method for producing a header according to an exemplary embodiment of the
invention is
described hereinafter in detail.
However, as an initial manner, reference is made to FIG. 1, which shows a
prior art water tank
11. Herein, it will be seen that the tank 11 is defined by a cylindrical wall
12 to which top 13 and
bottom 14 headers are welded. Each of the top header 13 and bottom header 14
has a main
body 15 having a plurality of landings 16 extending therefrom. The landings 16
in the bottom
header 14 serve as feet for the tank 11. Some of the landings 16 in the top
header 13 have
threaded fittings 17 welded thereto. Each threaded fitting 17 is defined by a
flange 18 welded to
the landing 16 and a tubular part 19 extending from the flange 18 and in which
threads are
defined. Each main body 15 is a stamped component produced from 0.135" HRP
draw quality
steel.
The method allows, inter alia, for threaded fittings to be provided on a water
tank top header
without the need for welding. This avoids, for example, weld splatter, as well
as the need for an
inventory of separate fittings, with commensurate impacts upon costs.
In the method, a blank of 0.135" HRP draw quality steel is stamped in a
conventional manner to
form a dish (not shown) generally in the form of the prior art main body top
header, but differing
in that 5/16" holes are provided in the landings that, in the prior art, would
have had threaded
fitting flanges secured thereto.
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Thereafter, a 0.960" extrusion punch, provided with a TD coating, is passed
through each hole
into a mating die to produce a boss. FIGS. 2-5 shows the construction of a
suitable punch;
FIGS. 6-9 show the construction of a suitable die.
To avoid tearing, the punch is lubricated with Syndraw 99 lubricant and passed
through the hole
at about 480 inch/minute or less.
Thereafter, a % NPT tap (not shown) is used to cut interior threads in each
boss.
FIG. 10 is a cross-section similar to FIG. 1 but showing the results of the
above method in a
completed tank 20. Herein, it will be seen that the tank 20 includes the
cylindrical wall 12 and
bottom header 14 of the prior art, as well as a modified top header 13' which
includes a
generally conventional main body 15 but, instead of welded threaded fittings,
has a plurality of
threaded bosses 22 extending from the landings 16.
Whereas a single embodiment is herein described, it will be evident that
modifications can be
made. Accordingly, the invention should be understood as limited only by the
accompanying
claims, purposively construed.
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