U.S. patent application number 10/017491 was filed with the patent office on 2002-08-22 for toilet system with reduced or eliminated flushing requirement, especially for transportation vehicles.
Invention is credited to Erdmann, Wolfgang, Gienke, Torsten, Heinrich, Hans-Juergen.
Application Number | 20020112281 10/017491 |
Document ID | / |
Family ID | 26053908 |
Filed Date | 2002-08-22 |
United States Patent
Application |
20020112281 |
Kind Code |
A1 |
Erdmann, Wolfgang ; et
al. |
August 22, 2002 |
Toilet system with reduced or eliminated flushing requirement,
especially for transportation vehicles
Abstract
A toilet system, especially for passenger transport vehicles,
includes a toilet bowl connected via a suction valve and a waste
collection pipe to a waste collection tank. Waste-contacting
surfaces of the toilet system that come into contact with urine and
fecal waste are coated with an adhesion-inhibiting or
adhesion-reducing nanocoating. Thereby, the adhesion of waste to
the toilet bowl and other components is significantly reduced, and
the total flushing water demand can be substantially reduced or,
preferably completely eliminated. An airflow flowing into the
toilet bowl, induced by the vacuum suction through the suction
valve, is sufficient to "flush" the waste material from the
nanocoated waste-contacting surfaces. The toilet system provides a
substantial reduction in the total system weight and in the
required quantity of flushing water that must be carried in the
vehicle, and thus makes the toilet system particularly applicable
for passenger transport vehicles such as aircraft.
Inventors: |
Erdmann, Wolfgang;
(Buxtehude, DE) ; Gienke, Torsten; (Pinneberg,
DE) ; Heinrich, Hans-Juergen; (Hamburg, DE) |
Correspondence
Address: |
FASSE PATENT ATTORNEYS, P.A.
P.O. BOX 726
HAMPDEN
ME
04444-0726
US
|
Family ID: |
26053908 |
Appl. No.: |
10/017491 |
Filed: |
October 22, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10017491 |
Oct 22, 2001 |
|
|
|
09603854 |
Jun 26, 2000 |
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Current U.S.
Class: |
4/321 |
Current CPC
Class: |
E03D 11/02 20130101;
B64D 11/02 20130101; Y02T 50/40 20130101; E03F 1/006 20130101; Y02T
50/46 20130101 |
Class at
Publication: |
4/321 |
International
Class: |
E03D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 1999 |
DE |
199 28 894.1 |
Claims
What is claimed is:
1. A toilet system for collecting waste material including at least
one of urine and feces, said system comprising: a toilet bowl with
a bowl outlet and a first waste-contacting surface adapted to come
into contact with the waste material; a waste discharge arrangement
that is adapted to convey the waste material from said toilet bowl,
and that includes a waste pipe connected to said bowl outlet and
adapted to convey the waste material therethrough, a waste
collection tank connected to said bowl outlet by said waste pipe
and adapted to receive and collect the waste material therein, and
a waste suction valve connected and interposed in said waste pipe
between said bowl outlet and said waste collection tank, wherein at
least one of said waste pipe, said waste collection tank and said
waste suction valve has a second waste-contacting surface adapted
to come into contact with the waste material; and a suction source
connected to said waste discharge arrangement and adapted to
provide a suction airflow that flows into said toilet bowl from an
outside environment outside of said toilet bowl, flows along said
first waste-contacting surface, and flows out of said toilet bowl
through said suction valve when said suction valve is open, such
that said suction airflow assists in removing the waste material
from said toilet bowl; and wherein at least one of said toilet bowl
and said waste discharge arrangement comprises a structural
substrate and a nanocoating disposed directly or indirectly on said
structural substrate so that said nanocoating forms at least one of
said first waste-contacting surface and said second
waste-contacting surface.
2. The toilet system according to claim 1, further comprising an
air jet arrangement that communicates from the outside environment
outside of said toilet bowl into said toilet bowl and that is
arranged and adapted to direct an air stream along said first
waste-contacting surface.
3. The toilet system according to claim 2, further comprising a
toilet lid adapted to selectively close and open a top opening of
said toilet bowl, wherein said air jet arrangement includes at
least one air nozzle oriented to direct the air stream along said
first waste-contacting surface.
4. The toilet system according to claim 2, arranged and adapted so
that the suction airflow through said suction valve drives the air
stream from the outside environment through said air jet
arrangement into said toilet bowl as at least a part of a totality
of said airflow.
5. The toilet system according to claim 1, wherein at least one of
said waste pipe, said waste valve and said waste collection tank
comprises said structural substrate and said nanocoating.
6. The toilet system according to claim 1, wherein said toilet bowl
comprises said structural substrate and said nanocoating, and
wherein said first waste-contacting surface is at least a portion
of an inner bowl surface of said toilet bowl.
7. The toilet system according to claim 6, wherein said nanocoating
is a thin film having a thickness in a nanometer range, and wherein
said thin film has been formed by a nanotechnology process.
8. The toilet system according to claim 1, expressly excluding all
means of supplying a flushing liquid into said toilet bowl.
9. The toilet system according to claim 1, further comprising a
base layer arranged between said nanocoating and said structural
substrate, so that said nanocoating is disposed indirectly on said
structural substrate with said base layer therebetween.
10. The toilet system according to claim 1, wherein said
nanocoating is disposed directly on and in contact with said
structural substrate.
11. The toilet system according to claim 1, wherein said
nanocoating consists essentially of a metal.
12. The toilet system according to claim 1, wherein said
nanocoating consists essentially of a polymer.
13. The toilet system according to claim 1, wherein said
nanocoating consists essentially of an element of the fourth group
of the periodic table.
14. The toilet system according to claim 1, wherein said
nanocoating consists essentially of at least one element selected
from the group consisting of Cr, Ti, Mn, Ni, Ta, Al, V, W, Co, Be,
Zr, Hf, Nb, Mo, C, Si, Ge and Sn.
15. The toilet system according to claim 1, wherein said
nanocoating consists essentially of at least one metal carbide.
16. The toilet system according to claim 1, wherein said
nanocoating consists essentially of at least one of a metal nitride
and a metal boride.
17. The toilet system according to claim 1, wherein said
nanocoating consists essentially of at least one compound having a
covalent bonding property.
18. The toilet system according to claim 1, wherein said
nanocoating consists essentially of at least one compound having an
ionic bonding property.
19. The toilet system according to claim 1, wherein said
nanocoating consists essentially of a sialon compound.
20. The toilet system according to claim 1, wherein said
nanocoating consists essentially of a nanocomposition of organic
and inorganic components, and wherein said nanocomposition has a
low surface energy.
21. The toilet system according to claim 1, wherein said
nanocoating has such a character that it provides a wetting angle
of 0.degree. to 10.degree. with respect to a droplet of the waste
material.
22. The toilet system according to claim 1, wherein said structural
substrate on which said nanocoating is disposed has a maximum
substrate surface roughness of less than 100 nm and a mean
substrate surface roughness of less than 10 nm.
23. A toilet system for collecting waste material including at
least one of feces and urine, comprising: a toilet bowl comprising
a bowl structure substrate, a bowl outlet, and a nanocoating that
is provided on at least a portion of an inner bowl surface of said
bowl structure substrate and that forms a first waste-contacting
surface adapted to come into contact with the waste material; a
waste discharge arrangement that is adapted to convey the waste
material from said toilet bowl, and that includes a waste pipe
connected to said bowl outlet and adapted to convey the waste
material therethrough, a waste collection tank connected to said
bowl outlet by said waste pipe and adapted to receive and collect
the waste material therein, and a waste suction valve connected and
interposed in said waste pipe between said bowl outlet and said
waste collection tank, wherein at least one of said waste pipe,
said waste collection tank and said waste suction valve has a
second waste-contacting surface adapted to come into contact with
the waste material; a suction source connected to said waste
discharge arrangement and adapted to provide a suction airflow from
said toilet bowl through said suction valve when said suction valve
is open, such that said suction airflow assists in removing the
waste material from said toilet bowl; and air directing means that
direct at least a portion of said airflow along said first
waste-contacting surface downwardly toward said bowl outlet; and
expressly excluding all means of supplying a flushing liquid into
said toilet bowl.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation-in-Part under 35 U.S.C.
.sctn.120 of our prior co-pending U.S. patent application Ser. No.
09/603,854, filed on Jun. 26, 2000.
PRIORITY CLAIM
[0002] This application claims the priority under 35 U.S.C.
.sctn.119 of German Patent Application 199 28 894.1, filed on Jun.
24, 1999.
FIELD OF THE INVENTION
[0003] The invention relates to a toilet system, especially for
transportation vehicles, including at least one toilet bowl
connected to a waste collection tank by a suction valve.
BACKGROUND INFORMATION
[0004] Transportation vehicles, particularly aircraft, have only a
limited capacity for carrying flushing liquid for rinsing or
flushing toilets and waste water. For this reason, transportation
vehicles often use toilet systems in which the toilet bowl is
connected to a waste collection tank by a suction valve, and
particularly toilet systems that are constructed as vacuum systems.
Conventional toilet systems use a flushing liquid to flush the
toilet bowl, whereby the flushing liquid can be fresh water or can
be in part so-called gray water, i.e., fresh water that has already
been used for hand washing or the like and may be supplemented by
deodorizers, disinfectants, etc. The flushing liquid is sometimes
referred to as "flush water" herein for simplicity.
[0005] German Patent 42 01 986 and corresponding U.S. Pat. No.
5,317,763 (Frank et al.), issued June 1994, disclose a vacuum
toilet that is essentially equipped with a trigger device, a flush
water valve, and a suction valve that is arranged in a connecting
conduit between the toilet bowl and the waste collection tank.
After the trigger is actuated, the flushing liquid is delivered to
the toilet bowl by means of control devices. Subsequently, the
suction valve opens and the waste contained in the toilet bowl is
flushed together with the flushing liquid into the waste collection
tank.
[0006] A brochure titled "Das Zentrale Vakuum Toiletten-System fur
die Schiffsausrustung" ("The Central Vacuum Toilet System for the
Outfitting of Ships") from the company sanivac Vakuumtechnik GmbH
of Wedel, Germany (1997) discloses a vacuum toilet system that is
used for marine vessels. This system, too, requires less flushing
water than the conventional gravity flush toilet systems because of
the use of vacuum technology that reduces the demand for flushing
liquid to approximately 1 liter per flush. This reference also
discloses that the waste pipe of the system may be a steel pipe
with an inner surface coating of plastic.
[0007] German Utility Model Publication DE 92 01 684 U1 discloses a
toilet arrangement in which an odor-binding agent or cleaning agent
is added to the flushing liquid in the flushing circuit. This
increases the effectiveness of the toilet flushing and reduces the
formation of odor. This reference further suggested coating the
toilet bowl with a layer of polytetrafluoroethylene (PTFE), to
facilitate the cleansing or flushing of fecal residue from the
toilet bowl.
[0008] European Patent Publications EP 0,295,508 and EP 0,363,012
disclose vacuum toilet systems that use "gray water", at least in
part, for rinsing or flushing the toilet bowl. In these cases, it
is necessary that the water previously used in the wash basins be
processed with a suitable filter technology in order to prevent
blockage of the flush water line. Thus, in addition to the
necessary controls for the flushing process, it is also necessary
with such systems to provide a water treatment process. Various
attempts have been made to provide waterless toilet systems, i.e.
toilet systems that do not require a flushing liquid for flushing
the urine and fecal waste from the toilet bowl, e.g. U.S. Pat. No.
3,457,567 (Criss) and U.S. Pat. No. 4,346,002 (Petzinger). These
are generally composting toilet systems that use a cone or wrapper
of paper or plastic for encapsulating the fecal waste in the toilet
bowl and then transporting the resulting encapsulated package by
vacuum suction through a waste line to a holding/composting tank.
The encapsulating wrapper aims to prevent direct contact of the
fecal waste with the inner surfaces of the toilet bowl, which of
course avoids the need of cleaning or removing the fecal waste from
the inner surfaces of the toilet bowl. In other words, such systems
do not have any waste-contacting surfaces in the toilet bowl or
waste lines, because the waste is fully encapsulated in a wrapper.
Such systems are not well suited to applications in commercial
passenger transport vehicles, because they are not sufficiently
robust and reliable. For example, experience has shown that
passengers often try to dispose of various items in addition to
feces and urine in the toilets, including feminine hygiene
products, bottle caps, razor blades, wrappers and packaging of
various products, etc. Such items will inevitably puncture the
waste-encapsulating wrapper, causing feces to directly contact,
soil and adhere to the inner surfaces of the toilet bowl and waste
line. Also in such systems, the wrapper-providing arrangement is
very subject to failure, and/or requires proper operating efforts
and procedures by the toilet user.
[0009] Reducing the amount of water or liquid required for flushing
the toilets is of great importance, particularly on board an
aircraft. On large capacity aircraft, for example that can carry up
to 500 passengers, sufficient water for flushing the toilets (fresh
water or "gray water") must be provided for each passenger to use
the toilet, with further consideration of the duration of the
flight. Although a number of toilet systems that require a reduced
volume of flushing liquid are already known, it is still important
and necessary, particularly for large capacity aircraft, to reduce
to a minimum (or entirely eliminate) the water demand for flushing
and rinsing purposes. This is particularly true for large capacity
aircraft that fly long distances (i.e. long flight durations) and,
accordingly, must otherwise carry an enormous amount of water. The
toilet system for an aircraft must also have a high reliability,
ease of use, and low maintenance requirement.
SUMMARY OF THE INVENTION
[0010] For the above reasons it is an object of the invention to
provide a toilet system that provides a further weight reduction
compared to the conventional systems. It is a further object to
minimize or completely eliminate the necessity for flush water and
thereby to simplify the system and provide a toilet system that is
particularly suitable for use in large capacity aircraft. Another
object is to provide a method of manufacturing such an improved
toilet bowl for a toilet system. The invention further aims to
avoid or overcome the disadvantages of the prior art and to achieve
additional advantages, as are apparent from the present
specification.
[0011] The above objects have been achieved in a toilet system
according to the invention in which the toilet bowl is connected by
a suction valve to a waste collection tank, and in which at least
some of the system components that come into contact with waste
material are provided with a nanocoating. Particularly at least a
portion of the inner bowl surface of the toilet bowl itself is
provided with a thin film coating deposited by nanotechnology
processes. The nanocoating is provided at least on the entirety of
the waste-contacting inner surface area of the toilet bowl,
preferably the nanocoating may cover a whole inner surface of the
toilet bowl. Such a nanocoating significantly reduces or eliminates
the adhesion of fecal residue and other wastes on the
waste-contacting surfaces of the toilet bowl, the waste line, the
flush valve, and/or the waste tank, and therefore reduces or
eliminates the demand for flushing liquid. The nanocoating also
avoids the need to provide wrappers or the like for encapsulating
the fecal waste in the toilet bowl, as in some prior art systems.
These features in turn simplify and reduce the weight of the
overall toilet system.
[0012] The toilet system according to the invention is particularly
advantageous because it provides a substantial reduction in weight
relative to the conventional systems. This is especially important
for the use of such toilet systems in aircraft. The overall amount
of flush water or liquid required for rinsing or flushing the
toilet can be substantially reduced or can even be completely
eliminated. The weight that is saved due to the elimination or
reduction of flush water can be used, for example, to allow
increasing the seating capacity in the transportation vehicle.
[0013] The invention further provides a method for manufacturing a
toilet system according to the invention. The surface of the toilet
bowl to be coated with the nanocoating can be pretreated with
grinding, polishing and surface cleaning operations. The
nanocoating can be applied by means of cathodic sputtering or gas
phase deposition processes such as chemical vapor deposition or
physical vapor deposition processes. Waste contamination and
adhesion of particles can be avoided particularly by applying the
nanocoating to the waste-contacting surface portion of the toilet
bowl that comes into contact with waste materials or is exposed to
a passenger.
[0014] In a further embodiment of the toilet system according to
the invention, the flush water and, consequently, the flush water
circuit, can be completely eliminated. This simplifies the system
by reducing the number of its components, and reduces the
maintenance and repair effort. By applying suction through the
toilet bowl outlet during the toilet bowl emptying process, an
airflow is sucked from the surrounding environment into the bowl
and downwardly to the bowl outlet, which assists in sweeping and
removing the fecal and urine waste from the nano-coated
waste-contacting surfaces of the bowl downwardly to the bowl
outlet. Optionally, the airflow can be enhanced or especially
directed along the waste-contacting surfaces by airflow directing
means such as an air jet arrangement (passive or active) or simple
airflow openings that direct the airflow toward and along the
waste-contacting surfaces. By means of this airflow, it is possible
to achieve good cleansing of the nano-coated waste-contacting
surfaces of the toilet bowl, with or without a minimum of flush
water, or simply with a very small amount of a deodorizer and
disinfectant.
[0015] According to the invention there are several alternatives
for forming the adhesion-inhibiting, or at least adhesion-reducing,
coatings. The nanocoating is preferably made of a metal, or an
element of the fourth major group of the periodic system, or of a
composition with a covalent bonding character or an ionic bonding
character. Alternatively, the nanocoating can consist of a sialon
composition, that is, an alloy of silicon nitride and aluminum
oxide, or a polymer. The nanocoating is preferably applied to
surfaces of the system components that are within the toilet bowl
area and/or come into contact with waste material. A base layer may
be applied to the area of the toilet bowl to which the nanocoating
will subsequently be applied to improve the retention of the
adhesion-inhibiting or at least adhesion-reducing coating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order that the invention may be clearly understood, it
will now be described in connection with example embodiments, with
reference to the accompanying drawings, wherein:
[0017] FIG. 1 is a schematic diagram of a first embodiment of a
vacuum toilet system with a toilet bowl according to the invention
using a reduced amount of flushing liquid;
[0018] FIG. 2 is a schematic diagram of a second embodiment of a
vacuum toilet system with a toilet bowl according to the invention
entirely omitting the use of a flushing liquid;
[0019] FIG. 2A is a schematic diagram of a variation of the toilet
bowl of the second embodiment of FIG. 2;
[0020] FIG. 3 represents a wetting angle of a conventional surface
without coating;
[0021] FIG. 4 represents a wetting angle of a surface coated with a
nanocoating according to the invention;
[0022] FIG. 5 schematically shows a toilet bowl according to the
invention; and
[0023] FIG. 5A shows the detail area 5A of the coating on the
toilet bowl of FIG. 5.
DETAILED DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS AND OF THE
BEST MODE OF THE INVENTION
[0024] FIG. 1 is a schematic representation of a toilet system 1
such as can be used in an aircraft A. The toilet system 1 comprises
essentially at least one toilet bowl 2 that is connected via a
waste water valve 3 to a waste collection pipe 4. It is possible to
connect a plurality of toilets located at various locations to the
waste collection pipe 4. The waste collection pipe 4 includes
pipes, conduits, hoses, or lines that are used to convey waste
material. The waste collection pipe 4 leads to a waste collection
tank 5 in which the waste material and waste water are collected. A
pressure differential between the toilet bowl 2, which contains
waste, and the waste collection tank 5 facilitates or effectuates
the waste transport operation. The toilet system 1 is constructed
therefor as a vacuum toilet system. A vacuum generator 6 generates
the necessary negative pressure. When used in an aircraft, the
vacuum toilet system 1 can also or alternatively take advantage of
the predominating reduced external atmospheric pressure during
flight to provide the pressure differential required for proper
functioning of the vacuum toilet system 1.
[0025] The waste collection tank 5 is further connected to a tank
drain valve 7 by means of which the collected waste water can be
discharged as needed. A flushing liquid dispenser, which is a rinse
or flush ring 8 in the example embodiments but may have any
conventionally known arrangement of a flushing liquid dispenser, is
provided on the toilet bowl 2. Instead of the flush ring 8, it is
possible to use other liquid dispensing means, such as one or more
individual water jets or nozzles arranged in the toilet bowl 2. The
flush liquid or water is guided from the flush ring 8 into the
toilet bowl 2 and cleanses the toilet bowl 2 during a flushing
operation. The flush water is drawn from a flush water tank 9 that
is connected by a feed line 10 and a flush water valve 11 to the
toilet bowl 2 (and particularly the flush ring 8) to be flushed or
cleaned. A control unit 12 controls the actions of the waste water
valve 3 and the flush water valve 11, responsive to the actuation
of a flush control button 12A that can be depressed by a passenger
who has used the toilet.
[0026] After the toilet has been used, the flushing operation is
initiated by the passenger by actuating the flush control button
12A or other trigger device to convey the fecal materials or other
waste material from the toilet into the waste collection tank 5.
The control unit 12 opens the flush water valve 11 and flush water
is sprayed or guided into the toilet bowl 2 from the flush ring 8
(for example, by means of spray jets, which will keep the amount of
flush water required for flushing as low as possible). The waste
water, i.e., fecal material and flush water, collects by the force
of gravity in a toilet drain 2B of the toilet bowl 2. The waste
water valve 3 then opens for a brief time and the waste material
that is collected in the toilet bowl 2 is conveyed out of the
toilet bowl through the bowl outlet or drain 2B, through the valve
3 and into the waste collection pipe 4, and from there into the
waste collection tank 5 by means of the pressure differential. An
airflow A that flows into the toilet bowl, being induced by the
just-mentioned pressure differential and suction out of the bowl
through the drain 2B, additionally "flushes" or "sweeps" the waste
material out of the bowl 2 through the drain 2B, as will be further
described below.
[0027] Flush water is necessary in conventional toilet systems in
order to clean the toilet bowl 2 of any waste material that remains
adhered to the inner surfaces of the toilet bowl 2. In order to
remove such waste or contamination with only a very small amount of
flush water or even without flush water, a relevant surface area of
the toilet bowl 2 according to the invention is coated with a
special nanocoating 15. The nanocoating 15 is applied to the
complete inside surface of the toilet bowl 2 or at least in a
waste-contacting surface area 2A that comes into contact with the
waste material, as indicated in FIGS. 1, 2, and 5. The structure
and the mode of manufacturing the nanocoating 15 is shown in more
detail in the FIGS. 3 to 5 and described in more detail below. The
nanocoating 15 has adhesion-inhibiting or at least
adhesion-reducing properties.
[0028] The first example embodiment of the toilet system 1, shown
in FIG. 1, uses a nano-coated toilet bowl 2 that requires a greatly
reduced amount of water for cleaning or flushing, relative to
conventional toilet bowls. This is achieved because the nanocoating
15 minimizes or prevents the adhesion of urine and fecal waste
material onto the inner surfaces of the toilet bowl 2, so that the
above mentioned airflow A together with a minimal amount of
flushing liquid and the effect of gravity are sufficient to remove
the waste material from the bowl 2 out through the drain 2B during
a flushing operation. Thus, particularly for large capacity
aircraft that fly long distances, the amount of water required for
flushing toilets is substantially reduced. As a result, additional
weight capacity is now available for additional passenger seats or
for other measures that will increase the comfort of the
passengers. Also, the waste collection tank 5 and the flush water
tank 11 that are required can be made smaller, as they are now
required to hold a lesser volume. This also results in a further
reduction of weight.
[0029] FIG. 2 shows a toilet system 20 according to a second
example embodiment of the invention. In this embodiment, the toilet
system 20 comprises a nano-coated toilet bowl 2 to which
essentially no waste material at all can adhere. Thus, with the
toilet bowl 2 according to this embodiment, rinsing or flushing
liquid to flush or clean the surface of the toilet bowl 2 is
completely unnecessary. Consequently, system components such as the
flush ring 8, the flush water tank 9 (or the fresh water feed
line), the feed line 10 and the flush water valve 11 become
superfluous and are thus not provided in the toilet system 20. This
is a substantial simplification of the overall toilet system 20,
which not only reduces the weight of the toilet system 20, but also
reduces the cost and effort of maintenance and repair.
[0030] The toilet bowl 2 of the toilet system 20 is provided with a
nanocoating 15 at least in the waste-contacting area 2A shown in
FIG. 5. This is the area where waste material comes into contact
with the surface of the toilet bowl 2. Due to the elimination of
the flush water valve 11, maintenance measures for cleaning,
decalcifying and replacing the seal elements of this valve 11 are
also eliminated and the overall reliability of the system increases
since leakages in the flush water circuit are also eliminated.
Moreover, the advantages mentioned in connection with the toilet
system 1 also apply to the toilet system 20.
[0031] The remaining system components of the toilet system 20 are
identical with those of the toilet system 1 shown in FIG. 1. The
elimination of the flush water feed simplifies the system control
and therefore the control unit 12 can also be simplified. With the
elimination of the flush water circuit, only the opening and
closing of the waste valve 3 is necessary to remove the collected
waste material from the toilet bowl 2. In other words, it is no
longer necessary to actuate a flush water valve in proper
coordination with the waste valve 3. Instead, the waste material
easily "slides" down from the nanocoated waste-contacting surfaces
2A, so that the waste material is completely removed from the
toilet bowl 2 by the combined effects of gravity and the induced
airflow A, without needing any flushing liquid. Namely, the waste
material is conveyed out of the toilet bowl 2 primarily by means of
the suction created by the vacuum that exists within the toilet
system, which in turn induces the airflow A into the toilet bowl as
described above, when the suction waste valve 3 is opened. The
airflow A is thereby caused to flow from the surrounding
environment outside of the toilet bowl 2, into the bowl 2, and
particularly directed downwardly along the nanocoated
waste-contacting surfaces 2A toward the outlet 2B. Moreover, the
downward force of gravity acts advantageously on the waste that
falls onto the surface of the toilet bowl 2 because of the minimal
adhesion properties of the nanocoating 15 provided on the
waste-contacting surfaces 2A of the toilet bowl 2. After the waste
material has been removed, the toilet bowl 2 is left in a clean
condition without having to be flushed with liquid.
[0032] As a further auxiliary alternative exemplified in FIG. 2A,
the toilet bowl 2 may be additionally equipped with airflow
directing means to passively or actively direct an airflow
forcefully along the waste-contacting surfaces 2A of the toilet
bowl 2. In the example of FIG. 2A, an air jet arrangement with air
jets 27 is provided instead of the water spraying flush ring 8 of
FIG. 1, so that one or more directed air jets blow downward along
the inner surfaces of the bowl to assist in moving any remaining
waste material down into the toilet drain 2B. For example, such air
jets 27 may be driven actively by a source of pressurized air, or
passively from the room air outside of the toilet bowl due to the
airflow induced into the bowl upon opening the suction waste valve
3. The air jets 27 may optionally be formed by air-directing
configurations on the bottom of a toilet seat provided on the
toilet bowl. As a further optional component, the toilet may be
equipped with a cover or lid 28, which selectively covers the bowl
2 in the usual fashion and/or also enhances the passive flow of
outside air through the air jets. For this purpose, the cover 28
may optionally be adapted to close the top opening of the bowl
sufficiently tightly to cause at least most of the induced airflow
A to enter the bowl through the air jets 27, if the cover 28 is
closed before actuating the suction waste valve 3.
[0033] FIGS. 3 and 4 illustrate to what extent a nanocoating will
reduce the wetting angle of a liquid or waste droplet 13 on the
surface 14 of a toilet bowl 2. FIG. 3 shows a conventional surface
14' without a coating or, for example, with a PTFE-coated toilet
bowl. A droplet 13 of water or urine or feces is located on the
surface 14 of the toilet bowl 2. The wetting angle 13A is
relatively large (e.g. 65.degree.) in the conventional toilet bowl
2 and thus the droplet 13 can adhere to the surface 14'.
[0034] FIG. 4 illustrates a wetting angle 13B of a droplet 13 on
the surface 14 of a toilet bowl 2 that is coated with a nanocoating
15 according to the invention. As can be seen, the wetting angle
13B on the nano-coated toilet bowl 2 is much smaller than that of
the uncoated toilet bowl shown in FIG. 3, and, as a result, the
droplet 13 will have a significantly reduced wetting adhesion on
the surface and will glide or roll over the surface of the
nano-coated toilet bowl 2 much more easily, simply under the force
of gravity. For example the wetting angle 13B may be in a range
from 0.degree. to 25.degree., or preferably 0.degree. to
10.degree..
[0035] The nanocoating 15 is produced by means of nano-technology
and is applied to the surface 14. The nanocoating 15 has a coating
thickness in the nanometer range, e.g. less than 10 nanometers, or
preferably less than 5 nanometers. Nanotechnology provides ordered
surfaces with a low surface energy, such that when such a surface
is wetted by a droplet, the wetting angle 13B approaches 0.degree.,
thereby providing a best possible achievable anti-adhesion coating.
This anti-adhesion nanocoating 15 inhibits or at least
substantially reduces the adhesion of the droplet 13 of water or
urine or particles of fecal matter to the surfaces of the toilet
bowl 2 and/or other components of the toilet systems shown in FIGS.
1 and 2 that are coated with the nanocoating 15. The droplets 13
fall under the force of gravity into the drain 2B of the toilet
bowl 2, which is also preferably coated, and are then suctioned off
by the effect of the vacuum via the waste collection pipe 4 into
the waste collection tank 5.
[0036] FIG. 5 shows a detail of the toilet bowl 2 according to the
invention and FIG. 5A shows a much enlarged sectional view of the
nanocoating 15 on the surface of the toilet bowl 2. Preferably, the
base material or structural substrate 2' of the toilet bowl 2 is
made of stainless steel, in view of its corrosion-inhibiting
properties, and its ductility or lack of brittleness. Synthetic
materials, e.g. plastics, however, may also be used for the toilet
bowl 2 and for other components of the toilet system.
[0037] In the embodiment shown in FIGS. 5 and 5A, the substrate 2'
of the toilet bowl 2 is first coated with a base coating 16. The
base coating 16 may be necessary in some cases, for example, when
it is difficult to apply the nanocoating 15 directly to the base
material or substrate of the toilet bowl for lack of adequate
adhesion or because the roughness is too great. In such cases the
nanocoating 15 can be produced with better results when applied to
the intermediate base coating 16.
[0038] In a preferred embodiment, the surface of the toilet bowl to
be coated is first pretreated before the base coating 16 or the
nanocoating 15 is applied. The surface is first subjected to a
grinding and polishing process in order to obtain a surface
roughness in the range of less than 100 nm and a mean roughness in
the range of less than 10 nm. Subsequently, the surface is cleaned
with an organic solvent and/or by an ultrasound cleaning
process.
[0039] The application of the nanocoating 15 to the toilet bowl 2
will now be described in greater detail. Preferably, metals or
elements of the fourth major group of the periodic system, or
alternatively and more particularly Cr, Ti, Mn, Ni, Ta, Al, V, W,
Co, Be, Zr, Hf, Nb, Mo, C, Si, Ge or Sn, or compounds with these
elements are used to make the nanocoating 15. It is possible to use
compounds with a metallic bonding property, in particular carbides
such as MC as well as secondary carbides M.sub.2C, M.sub.3C,
M.sub.6C, M.sub.7C, M.sub.23C.sub.6, whereby M designates a metal
or an intermetallic metal group. It is furthermore possible to use
nitrides of the structure MN or borides of the structure MB,
whereby, again, the M stands for a metal.
[0040] Alternatively, it is possible to produce the nanocoating 15
from a compound having a covalent bonding property such as, for
example B.sub.4C, SiC, BN, Si.sub.3N.sub.4 or MOS.sub.2.
[0041] In a further alternative, the nanocoating 15 can be made
from a composition having an ionic bonding property, such as, for
example Al.sub.2O.sub.3 or ZrO.sub.2 or BeO. In a further
embodiment the nanocoating 15 can be made from a sialon
composition, i.e., an alloy of silicon nitride and aluminum oxide,
or from polymers.
[0042] The nanocoating, also referred to as "thin films" or "ultra
thin films", can be produced by classic cathodic, or vapor
deposition or sputtering methods, or by means of resistance heating
through vacuum assisted processes. The demands on the production of
a coating by means of nanotechnology are characterized by
atomically precise boundaries and by controlling the deposition of
layers that are each only one atom thick. For the most part,
applied vacuum methods are based either on molecular beam epitaxy
(MBE) or deposition from a gas phase.
[0043] Possible methods of production are, for example: cathodic
sputtering; ionic implantation; sputter techniques (plasma beam
source, magnetron sputtering, radio frequency diode sputtering);
gas phase deposition (chemical vapor deposition--CVD, atomic layer
epitaxy--ALE, and chemical beam epitaxy--CBE); plasma assisted
chemical vapor deposition--PACVD; and physical vapor
deposition--PVD.
[0044] As a further alternative, an anti-adhesion coating can be
formed on the basis of inorganic-organic nanocompositions with a
low surface energy. Such a coating can be formed by generally known
coating techniques, such as dipping immersion, spray coating, or
centrifugal spin coating or the like, followed by curing or
hardening of the coating layer by UV-radiation and/or thermal
heating, whereby the resulting nanoparticles of the coating achieve
the desired anti-adhesion properties.
[0045] When producing the nanocoating 15 according to the possible
methods, it is essential that the nanocoating is formed rather soft
and non-brittle, as this will prevent parts of the nanocoating 15
from peeling from the toilet bowl 2.
[0046] The magnetron sputter technique is the preferred method of
producing the nanocoating 15. This technique, which is generally
known to the person of ordinary skill in the art, belongs to the
group of methods referred to as cathodic sputtering. According to
this method, the coating is applied in a vacuum and a solid base is
coated with metallic or non-metallic layers. The coating material
on the cathodes is atomized or sputtered by bombardment of the
material with gas ions in a gas atmosphere. The material is then
deposited on the toilet bowl substrate surface as a coating. The
ions ensure that the upper atomic layers from the coating material
are converted by impulse exchange into the gaseous state. The
coating material, now in a gaseous state, is then deposited on the
surface to be coated. The thermal stress on the toilet bowl
substrate to be coated is relatively low when this magnetron
sputtering technique is used. It is currently possible to attain a
coating diameter of up to 150 mm, with a coating rate of 0.1 to 1
mm/min when using a double ring magnetron source. According to the
invention, the nanocoating 15 is to be applied to rather large
surface areas of the toilet bowl, and optionally other portions of
the toilet system. Preferably, the whole inner surface of the
toilet bowl 2 is to be coated.
[0047] Application of the nanocoating 15 to the toilet bowl 2 has
been described in greater detail above. It is possible, of course,
to apply the nanocoating 15 using suitable application methods to
other components of the toilet system that come into contact with
fecal material or other waste material. It is within the scope of
the invention, for example, to coat the interior of the waste
collection pipe 4, or at least portions of the waste collection
pipe 4 such as branching areas, in order to reduce as much as
possible the effort involved with cleaning and maintaining the
toilet system.
[0048] Although the invention has been described with reference to
specific example embodiments, it will be appreciated that it is
intended to cover all modifications and equivalents within the
scope of the appended claims. It should also be understood that the
present disclosure includes all possible combinations of any
individual features recited in any of the appended claims. The term
toilet bowl herein includes all possible types and configurations
of toilets including sit-down toilets, crouching-type toilets,
urinals, etc.
* * * * *