METHOD OF NEUTRALIZING BACTERIA IN SULPHUR-CONTAINING HARD WATER IN A WATER HEATER

METHODE DE NEUTRALISATION DE BACTERIE DANS L'EAU DURE CONTENANT DU SOUFRE DANS UN CHAUFFE-EAU

English Abstract

A method of neutralizing odor-causing bacteria in sulphur-containing hard water in the tank of a water heater is described. The method comprises utilizing a 420 aluminum alloy sacrificial anode and introducing into the tank of the water heater zing, herein in pellet form, in the tank to prevent the formation of bad odor contained in the sulphur containing hard water by neutralizing the bad odor producing bacteria.

French Abstract

Une méthode de neutralisation de bactéries sources dodeurs dans de leau dure contenant du soufre dans le réservoir dun chauffe-eau est décrite. La méthode comprend lutilisation dune anode sacrificielle en un alliage daluminium 420 et lintroduction dans le réservoir du zeste du chauffe-eau, ici sous forme de pastille, dans le réservoir pour empêcher la formation de mauvaises odeurs contenues dans leau dure contenant du soufre en neutralisant la bactérie provoquant de mauvaises odeurs.

Claims

CLAIMS
1. A method of neutralizing odor-causing bacteria in sulphur-containing
hard water
contained in a tank of a water heater, said method comprising the steps of:
i) securing an aluminum alloy sacrificial anode to said tank and extending
into the hard
water contained in said tank, and wherein said sacrificial anode has 4 to 5 %
zinc, 0.05
to 0.25 % tin, 0.25 % max. silicon, and total impurities of 0.15 % max. with
the balance
being aluminum, and
ii) introducing in loose form a zinc metal in said tank of said water heater
wherein the
combination of said zinc metal with said aluminum alloy of said sacrificial
anode
neutralizes bacteria and prevent the formation of an undesirable odor in said
sulphur-
containing hard water contained in said tank.
2. The method according to claim 1 wherein said zinc metal is in pellet
form and
introduced in said tank with water contained within the tank whereby said
pellet does
not damage the glass lined inner surface of said tank by impact therewith.
3. The method according to claim 2 wherein said zinc pellet is a disc-like
pellet
having a diameter of 5/8 inch and a thickness of % inch.
4. The method of claim 1 wherein said water contained in said tank is hard
underground water having a hardness of at least 100 PPM.
5. The method of claim 1 wherein said aluminum alloy sacrificial anode as
compared to a magnesium sacrificial anode generates less than half of the
current
generated by a magnesium anode and therefore produces less than half of
hydrogen in
said water when operational.
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6. The method according to claim 2 wherein said water heater is one of a
domestic
and commercial water heater.
7. The method according to claim 1 wherein said method is a retro-fit
method.
7

Description

CA 02905742 2015-09-23
METHOD OF NEUTRALIZING BACTERIA IN SULPHUR-CONTAINING HARD
WATER IN A WATER HEATER
FIELD OF INVENTION
The present invention relates to water heaters and more particularly to the
neutralization of odor-causing bacteria in sulphur-containing hard water
contained in
such water heaters.
BACKGROUND OF THE INVENTION
Not all water supplies have the same quality water due to variations in its
mineral
composition. In certain regions water may produce bad odors, such as a rotten-
egg
smell due to certain types of bacterial produced by sulphur contained therein.
Such
water is known as hard water which emanates from underground where it is in
contact
with in all sorts of minerals. Such rotten-egg smell water when heated in a
water heater
is amplified. In an attempt to resolve this problem different aluminum
sacrificial anode
compositions have been developed wherein a certain percentage of zinc is
introduced
in the alloy. Sacrificial anodes are utilized in water heaters for cathodic
corrosion
protection of the cathode and which cathode consists of any exposed steel in a
flawed
glass-lined tank. The glass lining secured on the inside wall of the tank is
to isolate the
steel from the water and thereby increase the life span of the water heater.
However,
any flaws in the glass lining and about fittings exposes steel to the water
and this
causes electrolysis, a current flow, between the anode and the cathode and
deterioration of the sacrificial anode. The intensity of the current flow
amplifies the bad
odor of the water.
In an attempt to protect the steel tank from corrosion and reduce the bad
odors
generated by such hard water, an aluminum-zinc alloy material was utilized as
the
anode for replacement of the commonly used magnesium anode. This offered some
protection against certain bacteria contained in the water. The alloy
composition
contained zinc and trace metals, such as tin, iron and silicon and the balance
aluminum.
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CA 02905742 2015-09-23
However, these replacement anodes, during electrolytic reaction, produced more
hydrogen at the exposed steel surfaces than the magnesium anode when active.
It
was concluded that the higher production of hydrogen when combined with
sulphur in
hot water, accelerated the bad odors generated by the bacteria, particularly
when the
anode had been greatly consumed. Because such anode also deteriorated more
quickly, there was a need for replacement after about four years of service
which, of
course, is dot desirable and such also added to cost to the consumer.
It has also been expressed in the literature, that aluminum can be a health
hazard
when exposed to drinking water. Accordingly, if hot water from a water heater
containing an aluminum alloy anode is often utilized as drinking water, for
example in
admixture with instant coffee etc., it could create a health hazard in long
term. Powered
anodes is said to be a preferred solution to the use of aluminum anodes.
Another
solution is to treat the water with chlorine before it enters the tank, but
this is an
expensive solution.
SUMMARY OF THE INVENTION
It is a feature of the present invention to provide an inexpensive method to
resolve the above mentioned problem of bad odors in the hard water contained
in the
tank of a water heater.
Another feature of the present invention is to provide a method of
neutralizing
odor-causing bacteria in sulphur-containing hard water contained in a water
heater by
using an aluminum zinc alloy having a specific composition and introducing
loose zinc
metal in the tank of the water heater to neutralize the odor generating
bacteria in the
water.
According to the above features, from a broad aspect, the present invention
provides a method of neutralizing odor-causing bacteria in sulphur-containing
hard
water contained in a tank of a water heater. The method comprises securing an
aluminum alloy sacrificial anode to the tank and extending into the hard water
contained
in the tank. The sacrificial anode has 4 to 5 % zinc, 0.05 to 0.25 % tin, 0.25
% max.
silicon, and total impurities of 0.15 % max. with the balance being aluminum.
A small
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CA 02905742 2015-09-23
'quantity of zinc material is introduced in loose form into the tank. The
sacrificial anode
in combination with the zinc metal introduced in the tank neutralized the
bacteria and
prevents the formation of bad odor in the hot water
According to a further broad aspect of the present invention the zinc metal is
in
pellet form and introduced in the tank when the tank has water contained
therein.
According to a further broad aspect of the present invention the sacrificial
anode
is an aluminum alloy anode containing 4 to 5 % zinc, 0.05 to 0.25 % max.
silicon, and
total impurities of 0.15 % max. with the balance being aluminum.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention is now described with
reference
to the accompanying drawing in which:
Figure 1 is a schematic diagram of tank of an electric water heater
illustrating
some of the elements associated therewith and the sacrificial anode is an
aluminum
alloy anode and one or more zinc pellet is resting on the bottom wall of the
tank.
With reference to Figure 1, there is schematically illustrated an electric
water
heater tank, herein a steel tank 10 having an inlet water coupling 11
connected to a
domestic water supply line 12 and a dip tube 13 for admitting water under
pressure in
the bottom portion of the tank. The water being fed to the tank is from a
source of hard
underground water which produces a rotten-egg smell when not treated. Hot
water is
drawn from a short pipe 14 in the top portion 14' of the tank where the water
is at its
hottest temperature and fed to the hot water distribution conduit 15. The
water within
the tank is heated by resistive heating elements 16, or by a combustion
chamber under
the tank when the water heater is a gas water heater. Because water in the
supply line
12 may contain an undesirable amount of sulphur, it produces bad odors in the
water
and when the water is heated, the bad odor is amplified. The sacrificial anode
17, is
usually fabricated from magnesium, and protects any exposed steel of the tank
from
corroding. The replacement of the anode 17 with a certain aluminum alloy anode
containing zinc in small quantities of about 4 to 5 % and which alloy is
identified by the
number "420", is used in combination with zinc material introduced in the tank
in loose
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CA 02905742 2015-09-23
=
=
'form to neutralize these bad odors. Certain regions have so much sulphur in
their water
that both hot and cold water have strong rotten egg odors although heated
water
produces more bad odors. With the present invention these bad odors are
neutralized
in the hot water drawn from the water heater.
The aluminum/zinc alloy sacrificial anode "420" is certified for use in Canada
and
the alloy contains 4.0 to 5.0 A. zinc, 0.05 to 0.25 % tin, 0.25 % max silicon
or less and
total impurities of 0.15 % maximum with the balance being aluminum. In Canada
that
anode is CSA approved under Code C309.
I have experimented with the use of one of more small zinc pellets 18 loosely
introduced in the water within the tank to neutralize the bad odor-causing
bacteria which
produce the bad odors. This experimentation resulted from my observation that
in a
certain residential area where the water supply produce a rotten-egg smell
that certain
residences had drinking water which did not smell whereas in other residences
the
water did have the rotten-egg smell. From closer investigation I realized that
this was
due to the material utilized for the water conduits. Streets where the
underground
piping was constructed of galvanized piping seemed to have neutralized the
bacteria in
the water whereas in other type conduits the smelly water was present.
Accordingly, I have found from further experimentation that the use of the
"420"
aluminum alloy, and the small zinc pellets in combination when exposed to such
bad-
odor sulphur-containing hard water acted as a neutralizer to the bacteria and
produced
much less hydrogen than magnesium sacrificial anodes, when active.
My invention is thus simple and inexpensive and consists simply in the
addition of
a zinc material, herein in pellet/tablet form in the tank of the water heater
in combination
with a replacement sacrificial anode formed from the "420" aluminum alloy..
The pellet
18 is introduced when there is water in the tank not to impact and damage the
glass
lining on the inner surface of the tank. The pellet is a small disk-like
pellet in the order
of 5/8 diameter and % inch in thickness. In a 60 gallon tank only a few of
these are
necessary to neutralize the odor causing bacteria. Also, in the event that the
bad odor
resurfaces it is only necessary to introduce a few more pellets in the tank.
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CA 02905742 2015-09-23
My invention is also a retro-fit method wherein an existing water heater can
be
easily modified on site by replacing the sacrificial anode with the "420"
aluminum alloy
anode and adding zinc pellets into the water tank and thereby neutralizing the
bad odor
producing bacteria, Also, aluminum alloy anodes produce half as much current
as
magnesium anodes and this results in lower levels of H2S (hydrogen) gas and by
lowering the H2S the rotten-egg odor is decreased. Still further, the aluminum
alloy
"420" sacrificial anode is expected to have a life span of at least 15 years
which is much
greater than a magnesium sacrificial anode.
It is within the ambit of the present invention to cover any obvious
modification of
the preferred embodiment described herein provided such modifications fall
within the
scope of the appended claims.

Representative Drawing