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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to commercial and residential water heaters, and more
particularly to an apparatus for cleaning such water heaters by the
introduction of a stream of high-velocity water in a generally horizontal
spray pattern across the bottom of the heater tank and the simultaneous
opening of tank drain means diametrically opposed to the stream of water
to permit removal of that foreign matter without the necessity of draining
and refilling the tank.
2. Description of the Prior Art
A problem in the commercial and residential water heater industry is the
accumulation of scale and other foreign matter along the bottom of water
heater tanks. This accumulation of scale effectively shortens the life of
such water heaters because the scale acts as an insulator, causing the
tank metal to overheat and burn out. One device for cleaning water heaters
is described in U.S. Pat. No. 4,263,879, issued to Lindahl on Apr. 28,
1981. Lindahl provides a tubular member along the bottom of and within a
water heater tank. The tubular member has a plurality of small openings
through which vertical and horizontal streams of water are directed upward
and along the tank bottom. However, Lindahl merely appears to be directed
to the prevention of settling of scale and other foreign matter on the
bottom of the tanks. The Lindahl provisions for removal of solid materials
from the tank do not include drain means or the like. Rather, the streams
of water agitate and suspend the foreign matter within the heater, which
is then passed out through the top of the tank along with the heated
water.
U.S. Pat. No. 277,012, issued to Dinkel on May 8, 1833, discloses a
substantially vertically-directed spray of a sugar-water solution to clean
crystallized sugar crystals on tubes in a distillation apparatus. Dinken
apparently does not disclose means for cleaning sediment at the bottom of
a tank.
In contrast, U.S. Pat. Nos. 1,767,919 and 1,768,039, both issued to
Eiermann on June 24, 1930; and U.S. Pat. No. 2,024,564, issued to Brand on
Dec. 17, 1935, all disclose a means of cleaning the bottom of residential
hot water tanks. However, each of these patents require that the tank
first be drained, and then cleaned by introducing a cleaning spray from
above and onto the bottom of the tank. For example, the Eiermann '919
reference discloses at page 2, lines 54-65, that although the inflow of
water from the top of the cold water tube is usually sufficient to clean
the bottom of the water heater, the removal of accumulated sediment should
be effected by draining the heater, turning the water on so that it will
spray the bottom of the heater, and then refilling the heater for normal
operation. Similarly, the Eiermann '039 reference indicates at lines 68-85
substantially this same mode of operation. Finally, Brand indicates at
page 1, column 2, lines 14-16, that when it is desired to clean the
heater, the water contained within that heater is drained off through a
drain cock 16. Several other patents in the water heater or related arts
include U.S. Pat. Nos. 641,295, issued to Jackson on Jan. 16, 1900;
1,028,180, issued to Bayer on June 4, 1912; 1,582,148, issued to
Stockholder on Apr. 27, 1926; 1,696,005, issued to Kothe on Dec. 18, 1928;
2,137,253, issued to Thompson on Nov. 22, 1938; 2,290,368, issued to
Dutton on July 21, 1942; and 4,527,543, issued to Denton on July 9, 1985.
SUMMARY OF THE INVENTION
The present invention is an apparatus for cleaning a conventional
residential or commercial water heater, typically being of a cylindrical
shape and having a circular top and bottom. The apparatus includes a water
supply source or tube, and further includes water-discharging means for
permitting a high-velocity flushing or sweeping stream of water from the
water supply source onto the bottom and within the interior of the water
heater. The water-discharging means is disposed adjacent the bottom of the
water heater and provides its water stream in a generally horizontal
pattern across the bottom to dislodge scale and other foreign matter. Tank
drain means are provided, which are diametrically opposed to the
water-discharging means, and which effectively permit the removal of the
dislodged scale and foreign matter from the tank while the tank is being
flushed with water flowing through the water-discharging means. The water
supply source can be conventional piping which enters the tank through the
top, the side wall, or any other convenient portion of the tank. The
water-discharging means may comprise a nozzle having one or more orifices.
The invention is suitable for water heaters having either flat or convex
bottoms.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical section view showing the water-discharging means
entering the side of the tank in accordance with the invention;
FIG. 2 is a vertical section view showing the water-discharging means
entering the top of the tank and terminating near tne bottom of the tank
in accordance with the invention;
FIG. 3 is an enlarged view of the lower portion of the water heater shown
in FIG. 1, but with the stream of water flowing through the nozzle;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 1;
FIG. 5 is a sectional view taken along line 5--5 of FIG. 2;
FIG. 6 is a sectional view of a water heater which includes a
multi-orificed nozzle, or water-discharging means, adjacent the bottom of
the water heater;
FIG. 7 is a horizontal view of the multi-orificed nozzle shown in FIG. 6;
and
FIG. 8 is a sectional view which includes separate nozzles or
water-discharging means entering the side of the tank at different
locations.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, FIGS. 1-8, the water heater 10 is generally
vertically disposed and has a cylindrical side wall 12, a circular top 14,
and a circular bottom 16. The top and bottom are normally welded to the
cylindrical side wall to form a water-tight unit.
In the embodiment shown in FIGS. 1, 3, 4, 6, 7, and 8, the water heater 10
is provided with a first opening 18 in the side wall adjacent the flat 16
or convex 16a tank bottom. A water supply tube 20 enters the tank at this
first opening 18. The tube 20 terminates at a nozzle 22 or 22b which is
configured to provide a generally horizontal flow of water across the tank
bottom 16 or 16a.
The nozzle directs a stream of water 24 across the tank bottom in a
generally horizontal spray pattern to facilitate the flushing of any scale
or foreign matter accumulated along the bottom. A drain cock or the like
28 may be provided diametrically opposed to, i.e., substantially across
from, the first opening 18. The drain cock enters the tank through a
second opening 30 in the side wall 12. During normal operation of the
water tank, this drain cock is left in a closed position. The nozzle may
be one including either one orifice 22 or a plurality of orifices 22b as
shown in FIGS. 3, 4, 6, 7, and 8, respectively.
Alternatively, the residential water heater may be of a configuration as
shown in FIGS. 2 or 5. With this configuration, the water supply tube 20a
enters the tank at the top 14a rather than through side wall 12a, and
terminates in a nozzle 22a which is disposed adjacent the lower end of a
tank 10a which is shown having a generally convex bottom 16a. The
horizontal stream of water 24a passes across the uppermost portion of the
convex bottom 16a where the greatest potential for damage from the
accumulation of foreign matter exists. In a heater having a plurality of
flue pipes, each of which reaches the tank bottom, extra nozzles could be
provided for flushing between the flue pipes. What is most important is
that the nozzles provide a substantially horizontal flow of water across
the tank bottom in a direction towards the tank drain means 28 or 28a.
The operation of the novel water heater cleaning apparatus may best be
understood by a review of the FIGURES and the accompanying text. The water
within the water heater is heated by the hot gases and products of
combustion passing through flue tubes (not shown) within the heater in a
manner well-described in the prior art. The problem that the present
apparatus seeks to alleviate is the tendency of various dissolved solid
materials in the water within the heater to precipitate out of that water,
and then accumulate at the bottom of the tank. If these precipitates are
not periodically removed by some sort of tank cleaning system or regimen,
the accumulation at the bottom of the tank will lower heating efficiency
and can cause overheating, corrosion, and metal failure of the tank
bottom.
A cold-water inlet tube 32 enters the top of the tank (FIG. 1) and provides
a source of cold water through water-fill tube 40, to be heated in the
tank 10. The inlet tube 32 and water-fill tube 40 are communicative with
water supply tube 20 through a tee fitting 26. Under normal operation,
manually-actuated valve 34 in water-fill tube 32 is open, and valve 36 in
water supply tube 20 is closed.
In contrast, when tank cleaning is desired, valve 34 is closed and valve 36
is opened. In this manner, as may be seen in FIG. 3, a stream of water 24
is discharged adjacent the bottom 16 of the water heater 10 in a generally
horizontal spray pattern to flush and agitate any settled foreign matter.
When valve 36 is opened, drain cock 28 is simultaneously opened so that as
the stream of water carries the foreign matter 38 from the tank bottom 16
and towards the drain cock 28 which is diametrically opposed to the first
opening, the scale and other foreign matter is discharged through the
drain cock 28. Because of the spacing of the nozzle adjacent the tank
bottom and the relative positioning of the discharge means or drain cock
28, the sediment can be removed without discharging the contents of the
tank, as taught in many of the prior art patents cited above.
It will be understood by those skilled in the art that the
manually-actuated valves 34 and 36 and drain cock 28 may be replaced by
electrically-actuated valves or the like, which can be automatically
controlled to provide for tank flushing at regular intervals. A pulsing
flow of water to the nozzle could be used. Alternatively, water flow in
the multi-orifice nozzle 22b could be alternated through the various
orifices.
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