Method for testing the effectiveness of drain cleaners

Details Method for testing the effectiveness of drain cleaners Method for testing the effectiveness of drain cleaners

1999-07-13

2002-07-16

Williams, Hezron (Department: 2856)

Measuring and testing

Testing of apparatus

Reexamination Certificate

active

06418803

ABSTRACT:

CROSS REFERENCES TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable.
BACKGROUND OF THE INVENTION
The present invention relates to methods for testing the effectiveness of drain cleaners on clogs commonly experienced in plumbing drains.
Most plumbing drains have a vertical entry which extends directly or indirectly into a U-shaped section that is referred to as a “trap”. Liquid typically remains in the trap at all times, thereby preventing sewer gases from returning up into the building through the drain (hence the gases are trapped). Downstream of the trap are one or more laterals and connectors that ultimately link the drain to the sewer system.
Drains for bathroom sinks and certain bathtubs often have a pop-up type valve mounted in their vertical entry. Kitchen sinks often have their vertical entry covered by a removable strainer. Other bathtubs have screens or stoppers covering their drain entry.
Given these obstructions, and that piping is usually a non-transparent metal or plastic, it is difficult for a consumer (or even a plumber) to know what is causing a particular clog, much less exactly where the clog is. The art had believed that hair was the primary cause of household clogs. This is in part because removal of the pop-up valve or other valve structure often disclosed wads of hair tangled around the valve. However, much less was known about where downstream clogs form, and what they are formed from.
It has therefore been difficult to optimize or completely evaluate drain cleaners. Potential drain cleaners have typically been tested in a laboratory by how quickly they dissolved hair in a container (see e.g. U.S. Pat. No. 5,630,883). The disclosure of this patent, and of all other publications referred to herein, are incorporated by reference as if fully set forth herein. While this technique has value, the value is limited to particular types of clogs.
Consumer feedback is of only limited value with respect to drain,cleaner effectiveness. When a clog is successfully chemically dissolved by a consumer, it is seldom clear where the clog was, how serious it was, and what it was made of. When a chemical drain cleaner fails to remove the clog, a plumber is usually called in to dislodge the clog using a plumber's snake or other equipment. The dislodged clog is usually washed into the sewer system, with the result that essentially nothing is learned about why the chemical drain cleaner failed.
Complicating matters is the fact that parts of many drain assemblies (especially those extending from bathtubs) are for, all practical purposes inaccessible (except through the drain inlet) once the building has been constructed. Even when the trap area and some downstream connectors are accessible (as is typical for a kitchen sink), the piping is typically made of plastic or metal so that the nature and placement of the clog cannot be easily determined.
Another problem is the reluctance of certain regulatory authorities to permit certain types of comparative advertising claims in the absence of more representative scientific experiments. Thus, consumers have not been able to receive sufficiently detailed comparative information relevant to the effectiveness of drain cleaners in the marketplace.
Thus a need exists for improved methods for testing chemical drain cleaners.
BRIEF SUMMARY OF THE INVENTION
In one aspect, the invention provides a method for testing a chemical drain cleaner. One obtains a test drain having a vertical entry, a trap extending downstream from the vertical entry, a lateral extending downstream from the trap, and mounting means in at least one of the vertical entry and the lateral for mounting a test clog.
One positions the test clog in the drain at the mounting means. One then adds a chemical drain cleaner to the drain through the vertical entry. Thereafter, one pours rinse fluid (usually water) into the vertical entry. One then measures the amount of residual test clog left in the drain or the flow rate through the drain after the treatment. In an alternative form, the test clog is made of hair and the trap is u-shaped.
If desired, the hair can be coated in a polysaccharide to simulate some of the effects of biofilm on drain clogs. Alternatively, hair coated with naturally formed biofilm can be used in the test drain.
The method can test a wide variety of cleaners such as those containing caustic materials such as sodium hydroxide, mixtures of sodium hydroxide, metal (e.g. aluminum) chips, and sodium nitrate, or alkaline sodium hypochlorite solutions (e.g. U.S. Pat. No. 4,080,305), as well as other cleaners such as those with additives such as surfactants, proteolytic enzymes, and disulfide reducing agents. See e.g. U.S. Pat. Nos. 4,540,506, 4,619,710 and 3,503,890.
By the term “chemical drain cleaner” I mean any liquid or solid material, other than water or water from a plumbing supply (e.g. softened water; hard water), which is being tested for use (or used or marketed for use) to remove drain clogs and/or to, protect against drain clogs. Thus, laundry bleach would be deemed to be a chemical drain cleaner when tested or used for drain cleaning, or earlier when that bleach was actually marketed for that purpose.
The mounting means is preferably the radially inwardly projecting stem of a pop-up valve (or other bar that can be radially inserted through a side wall of the vertical entry or lateral). It is preferably positioned at a point in the drain having a diameter of about 2.0 to 5.0 cm. One example is the assembly of
FIG. 1
of U.S. Pat. No. 2,486,246 (stem end
26
).
The parts of the drain (e.g. the lateral and trap) are designed to be uncoupled (by threading) from the trap (e.g. to provide access to the mounting means downstream of the trap).
In another form, the flow rate is monitored after the drain cleaner is added until the rinse water is added. This provides information regarding how long the drain cleaner adheres to the drain and drain contents.
Rinse water flow rates can also be monitored. The rinse water is preferably tested at selected intervals to determine drain cleaner content. This is preferably done by emptying the trap prior to rinsing. This technique permits an evaluation of the adherence of the drain cleaner to the clog.
In an alternative embodiment, such a drain is provided.
The objects of the present invention therefore include providing methods of the above kind:
(a) that permit the evaluation of drain cleaners;
(b) which permit drain cleaners to be developed that have improved effectiveness for particular types of clogs; and
(c) which evaluate comparative effectiveness of drain cleaners.
These and still other objects and advantages of the present invention (e.g. providing the drains) will be apparent from the description which follows. The following description is merely of the preferred embodiments. Thus, the claims should be looked to in order to understand the full scope of the invention.


REFERENCES:
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C. Potera, 273 Science 1795-97 “Biolfilms Invade Microbiology” (1996).
J. W. Costerton, 15 J. Ind. Microb 137-140 “Overview of Microbial Biofilms” (1998).
Letter from S.C. Johnson & Son, Inc. to National Broadcasting Company dated Oct. 10, 1997 regarding Advertising for “Drano Max” brand drain clog remover.

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