Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02318431 2000-09-22
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WATER SANITIZING SYSTEM
Field of Invention
S This inveni:ion relates to systems for sanitizing and distributing water for
use
in dental and other medical procedures. In particular, this invention relates
to a water
sanitizing system and a distribution system for supplying sanitized water to
existing
delivery systems and devices for use during dental procedures.
Backsround of the Invention
All dental offices routinely use water operated instruments in dental
procedures, which require the water to be delivered in a controlled manner.
Municipal
tap water is frequently the source of this water. While municipal tap water
must
usually pass certain government standards so that it is generally safe to
drink, tap
water may contain, levels of bacteria and other micro organisms which are
unacceptable for use in medical procedures. These types of procedures require
a
source of sterile water.
The municipal water supply may contain contaminating bacteria and other
micro-organisms which can serve as a source of infection. As such, a sanitized
water
supply for irrigati~~n of target areas, such as surgical wounds and for
cooling of high
speed dental instn~rrients is important.
While it is. known to use sterile solution sources such as bottled water or
saline
solutions, many procedures, such as those utilizing micro abrasive techniques,
require
a large source of water for irrigation. The use of bottled fluids is
impractical where
large quantities oiE sanitized water are required.
Moreover, even a sterile water supply can become contaminated with bacteria
and other micro-organisms. For example, while sterile water can be provided to
the
delivery systems, this water may still become contaminated as a result of
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contamination of the water supply tubing. Moreover, in a dental distributing
apparatus contamination may be introduced into the water supply from an air
supply
used to pressurize bottled water, where micro-organisms in the air supply are
exposed
to the water in the distributing apparatus. Also, contamination through
backwash
from a patient's mouth can occur when the water supply is shut off while
instruments
are positioned in a patient's mouth, so that a small amount of fluid is
hydraulically
drawn into the wager distribution system. This can quickly lead to
contamination of
the entire water distribution system, increasing the likelihood of infection
and the
spread of infection from one patient to other patients.
This poses a particular problem in dental offices and clinics. Left unchecked,
bacteria can accurrmlate over time within the distribution system to form a
bacterial
film on the inner surface of water supply lines used to distribute and
dispense water in
dental procedures ~3nd for cooling dental instruments. From time to time
pieces of this
bacterial film can break free and enter the water supply lines. These pieces
of
bacterial film can l;reatly increase the chances of infection where, for
example, open
wounds are being i:rngated by the water supply.
Various techniques have been used to combat the problem of bacterial
contamination of tlae distribution system, most involving flushing of the
distributing
system by a chemical sanitizing solution. For example, United States Patent
No.
5,199,604 to Palmer and United States Patent No. 5,709,546 to Waggoner
disclose the
use of bactericidal solutions to irrigate and flush the water supply systems.
A
commercially available disinfectant such as BIO 2000 (Trademark), formerly
sold
under the name STERISOI, (Trademark), can be used to disinfect the tubing and
water channels associated with a water distributing apparatus. However, these
solutions address only contamination of the distributing system, and do not
address
the problem of a contaminated water supply.
Solutions to this problem involving treatment of the water supply have been
proposed, for example United States Patent No. 5,158,454 to Viebahn discloses
a
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method of treating the water by incorporating a strong oxidant or ozone into
the water,
or some type of filta~ation, such as United States Patent No. 5,230,624 to
Wolf et al.
which teaches the use of an in line filter containing a polyiodide
purification resin for
filtering the bacteria and micro-organisms. In any technique involving the use
of an
external bactericidal agent to treat the water the agents must be added to the
water and
thereafter removed :from the system, either by a second treatment or by
flushing the
system with water. These steps must be repeated regularly. Moreover, available
bactericidal agents <~re restricted to those which are not toxic to humans,
and many of
these can be unplea:>ant in terms of taste or effect in a patient's mouth.
Filtration
treatments usually require that a filter be changed at regular intervals as
filtered micro-
organisms accumulate and render the filter less effective, or eventually
provide a
separate source of c~~ntamination.
It would accordingly be advantageous to provide in such a water distributing
apparatus a water supply sanitizing system which does not involve the use of
chemical
sterilizing agents or filters, and which uses ordinary tap water to provide a
constant,
adequate supply of sanitized water, for example for use with dental procedures
that
require large volumf;s of water. The present invention provides a batch
sanitizing
system which produces a convenient supply of sanitized water in batches,
dispensing
a sanitized batch of,water while a subsequent batch of water is being
sanitized.
Some dental delivery systems provide a source of disinfectant to sanitize the
delivery system. In some of 'these systems the disinfectant source is
comlected to the
oral cavity water delivery system at a single point from a toggle-operated
selector
valve, which enable:. the entire delivery system to be supplied with all water
or all
disinfectant on a mutually exclusive basis.
Other systems provide for air, water and disinfectant to be delivered via a
three-passage manifold, from which the dental instruments are supplied
directly and
therefore by pass the complex air and water regulating and control devices
built into a
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CA 02318431 2001-08-20
dental-chair delivery system. Water and disinfectant supplies are selectable
only on a
mutually exclusive basis.
It would be accordingly advantageous to provide a dental delivery system
having the capability of providing water and disinfectant concurrently to
different
parts of the delivery system on a non-exclusive basis. The present invention
provides
a dental dispensing apparatus capable of supplying disinfectant to certain
dental
delivery systems and devices while providing a supply of sanitized water to
other
certain dental delivery systems and devices.
The present invention thus provides a water sanitizing device, comprising: a
water
inlet for connection to a municipal water supply, a sanitizing region in fluid
communication
with the water inlet, for sanitizing water from the water supply to produce a
batch of sanitized
water, the sanitizing region having a sensor for detecting when a sanitizing
cycle is
completed, a reservoir at a lower level than the sanitizing region, for
storing the batch of
sanitized water, in fluid communication with the sanitizing tank and having a
water outlet, an
upper limit level sensor and a lower limit level sensor, and a valve disposed
between the
sanitizing region and the reservoir to permit a flow of water from the
sanitizing tank to the
reservoir when the lower limit level sensor detects that a water level in the
reservoir has
reached a selected lower limit and the sensor in the sanitizing region detects
that water in the
sanitizing region is in a sanitized condition.
The present invention further provides a method of dispensing sanitized water,
comprising the steps of: (a) sanitizing a batch of municipal tap water in a
sanitizing region;
(b) detecting a water level in a reservoir in fluid communication with the
sanitizing region
and detecting a condition of water in the sanitizing region; (c) draining the
batch of sanitized
water from the sanitizing region to the reservoir responsive to the water
level in the reservoir
reaching a selected lower limit and the sensor in the sanitizing region
detecting that water in
the sanitizing region is in a sanitized condition; and (d) dispensing the
sanitized water from
the reservoir.
Brief Description of the Drawings
In the drawings which illustrate by way of example only preferred embodiments
of
the invention,
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Figure 1 is a schematic diagram of a sanitizing tank of a water sanitizing
system according to the present invention;
Figure 2 is ~~ schematic diagram illustrating the reservoir component of the
sanitizing system of Figure 1;
Figure 3 is a schematic diagram of a dental delivery system according to the
presentinvention;
Figure 4 is a schematic diagram of a further embodiment of the present
invention; and
Figure 5 is a schematic diagram of the electrical circuits of the sanitizing
system of Figure 4.
Detailed Descnptio:n of the Lnvention
Figures l and 2 illustrate a preferred embodiment of the device and system of
the invention. Tap 'water from a municipal water supply is supplied to the
water
sanitizing system 10 through inlet 12 in fluid communication with a sanitizing
region
by free discharge, to provide separation from the municipal supply system.
Preferably, control of flow of the tap water into the sanitizing region is
controlled by
float operated valve 16.
In the preferred embodiment, the sanitizing region comprises a sanitizing tank
14, illustrated in Figure 1, comprising a conventional reverse-osmosis water
purifying
system. The tap water that is supplied to the sanitizing tank 14 is filtered
through a
semi-permeable membrane 1 S. Water is allowed to pass through the membrane 15
but the membrane 1:5 is impermeable to contaminants such as particulates,
bacteria
and pyrogens contained in tap water which are concentrated at the membrane 15.
This
material can later be removed or flushed from the system 10.
The sanitizing tank 14 is in fluid communication through drain valve 22 with a
reservoir 20 in which the sanitized water is stored for use in dental or other
medical
procedures. Optionally an overflow outlets 24 are provided to divert outflow
from the
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sanitizing tank 14 tr~rough valves 25 into drain 26, which allows the
sanitizing tank 14
to be drained for cleaning.
As shown in Figure 2, the reservoir 20 is provided with upper and lower limit
S level sensors comprising high level sensor 28 and low level sensor 30 which
respectively detect high and low water level limits for the sanitized water
within the
reservoir 20. The le~~el sensors 28, 30 are in electrical communication with
valve 22,
preferably a solenoi~~ valve, which controls the flow of sterilized water from
the
sanitizing tank 14 to the reservoir 20. The reservoir 20 is also preferably
provided
with a removable airtight lid 29 to facilitate thorough cleaning and
disinfecting of the
reservoir 20, and a drain 21 which allows the reservoir 20 to be emptied
through valve
23 into drain 21 for cleaning..
Preferably water drains from the sanitizing tank 14 to the reservoir 20 by
gravity feed, and the: sanitizing tank 14 is accordingly positioned at a level
higher than
the reservoir 20, to :supply a bead pressure for refilling the reservoir 20.
Sanitized
water is preferably dispensed from the reservoir 20, for example into a dental
dispensing apparatu;s such as that shown in Figure 3, under pressure from a
pressurized air source in communication with the reservoir 20 through inlet
34.
The pressuri;rxd air source may be the same air source used to distribute and
dispense air in the dental offrce, or a separate air source may be provided.
Preferably
the solenoid valve 3 6 is a three-way solenoid valve with an air relief port,
which
allows for air to be released from the reservoir 20 as it fills with sanitized
water from
the sanitizing tank 14. Also, when the low level sensor 30 detects a low level
condition in the reservoir 20 conventional control circuitry (not shown)
closes the air
valve 36 to relieve any residual pressure in the reservoir 20 through the air
relief port
of the valve 36 before the valve 22 is opened, to prevent backflow from the
reservoir
20 to the sanitizing tank 14. 'When the high level sensor 28 detects a high
level
condition the control circuitry closes solenoid valve 22 to shut off the
supply from
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sanitizing tank 14 and open the solenoid valve 36 to inaoduce pressurized air
to the
reservoir Zf? far further dispensing.
-~ In the preferred einbodi~ent. the hatch of v~acer stoied bctweeri the upper
sad
lower levZl limits of the reservoir 20 may be approximately one gallon
(approx. ~-5
litres), which is suitable for most dental procedures. For special procedures
requiring
more water, or for use in industrial prorxsses or other medical uses iu wlsich
a higher rate
of sanitized water supply may be required, the capacity of the sanitising tank
14 andlor
the reservoir 2(J eau be adapted accordingly. In any case the sanitization
process
s,ccotding to the invention operates $s a batch procedure, ~esein a
predetttmirxd
volume of water is being saaitized In the sanitizing tank 14 while a
previously
sanitized batch of water is available for dispcasing from the re9erwir 20 in
the
m>trnt><cr indie>atcd above.
An erx~foodimeui of a dr~tnl dispensing apparatus 2 utilizing as air/water
distribudoo system commonly found in dental chairs is shown in Figure ~ by way
of
example. However, the sanitizing system of the invention is capable of more
~ataral
application and is not limited to use with any particular dispensing apparatus
or
distribtttioa systtm. Conversely, t!?e dispensing apparatus of rise invention
is not
iimited Lo use with the !?etch sanitizing system of the invcation, althorsgh
it maty be
advrxvtageously so employed.
'fhe dispetu:ag apparatus 2 is capable of inter:ucing with cxistiag air and
water regulating and control devices in a dental office, providirr;g
decontarlnisastion and
flushing facilides and select'tttg particular devices, such as high-Speed
drills, to be
supplied with either' water or disinfectant while maintaining "water only"
supplies to
other insuumcuts such as syringe. ?hus, unlike cvr:ventional dispeasipg
syste><ris the
provi'ion of saniti~oed water oc disinfovtant in dtt dispcnaing system of the
iavention
is oa a non-exclusive basis. .
3U
7
AMENDED SHEET
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Sanitized water is fed to the water distributing or dispensing apparatus 2
shown in Figure 3 on demand through reservoir outlet 38, controlled by
solenoid
valve 42. Sanitized water from the batch sanitizing system shown in Figures 1
and 2
is supplied to an existing utility module 41 at inlet port 47 in the dental
dispensing
apparatus 2 through main shut-off valve 42.
Sanitized air from an external compressed air system (not shown) is provided
through main shut-off valve 43 of the dispensing apparatus 2. The air travels
through
suitable tubing to the inlet port of the point of a conventional point-of use
use air filter
45 (typically integrated into the dental chair) where the air is filtered.
Filtered air
egresses from the outlet port of the filter 45 and flows to the inlet port 60
of the air
manifold 46. The filtered air is supplied to inlet port 44 of the utility
module 41
through outlet port Ei 1 of the manifold 46 to provide the necessary pressure
to supply
the air delivery requirements of the dental dispensing apparatus 2. Air is
supplied
directly from the compressor to the reservoir 20 through inlet 34.
The pressurized sanitized water is supplied through outlet port 48 of utility
module 41 which is in fluid communication with one of the inlet ports of
selector
valve 49. The outlet port of valve 49 is connected to inlet port 72 of water
manifold
50. Outlet port 73 of the water manifold 50 is in turn in fluid communication
with
oral cavity water inlet port 52 of control block 53. Similarly outlet port 75
of water
manifold 50 is in fluid communication with syringe block 8. Existing tubing
for
supplying air from tlhe utility module 41 to the various dental devices such
as drills 4
and syringes 6 remains unchanged, allowing the distribution system 2 of the
invention
to be readily incorporated into existing dental office equipment.
The disinfectant bottle assembly 62 is supplied with air from outlet port 67
of
air manifold 46 via yin air-pressure regulator 63 and shut-off valve 64. When
air
pressure is applied tn the bottle assembly 62, the disinfectant solution is
driven up a
dip-tube to one inlet port of selector valve 65; the outlet port of valve 65
is connected
to inlet port 80 of disinfectant manifold 66.
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Water and disinfectant supplies to additional devices such as a cavitron
device
may be provided from ports 76 and 86 of the manifolds, respectively, if
required.
The outlet port 70 of water manifold 50 is connected to the second inlet port
of
selector valve 65, arid outlet port 83 of disinfectant manifold 66 is
connected to the
second inlet port of selector valve 49.
Outlet port .'3 of water manifold 50 is connected to one inlet port of
selector
valve 54. Inlet port 52 of control block 53 is connected to the outlet port of
selector
valve 54. Outlet port 84 of disinfectant manifold 66 is connected to the other
inlet
port of selector valve 54.
Water outlet port 55 of control block 53 is connected to one inlet port of
selector valve 56. Outlet port 74 of water manifold 50 is connected to the
other inlet
port of selector valve 56. The outlet port of selector valve 56 is connected
to a syringe
6.
The operation of the preferred embodiment of the invention will be described
in the context of the dental delivery system of Figure 3. When main air valve
43 is
open, air is supplief~, to utility module 41 via air filter 45 through air
manifold 46 and
communicated to inlet port 44 of the utility module 41. Air is also supplied
to
disinfectant bottle assembly 62 via air manifold 46, regulator 63 and control
valve 64.
The existing air delivery system from the utility module to various devices
(not
shown) is conventional and well known to those skilled in the art.
When main 'water valve 42 is open, sanitized water is supplied from the
reservoir 20 to utility module 41 at inlet port 47 and regulated sanitized
water for use
in, for example, the oral cavity, exits at port 48 and flows to selector valve
49.
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When valve 49 is in the "WATER SUPPLY" position A, the water manifold
50 is charged with water which can then be delivered to various devices. For
example, when valve 49 is in the "WATER SUPPLY" position A and valve 54 is in
the "WATER SUPPLY" position C, the high speed drill 4 receives water through
the
master block 51; similarly, when valve 56 is in the "WATER SUPPLY" position E,
syringe 6 receives water through port SS of the control block 53. Assistant's
syringe
block 8 has an uninterrupted water supply directly from port 75 of manifold
S0.
As the batch of sanitized water is depleted and the water level in the
reservoir
20 reaches the low level sensor 30, conventional control circuitry closes main
shut-off
valve 42, closes the air valve 36 to relieve any residual pressure in the
reservoir 20
through the air relief port of the valve 36, and opens valve 22 to drain
another batch of
sanitized water into the reservoir 20. When the high level sensor 28 detects a
high
level condition the solenoid valve 22 is closed to interrupt communication
between
the reservoir 20 and the sanitizing tank 14, the main shutoff valve 42 is
opened to
restore the supply oil sanitized water to the dispensing apparatus 2, and the
solenoid
valve 36 is opened to reintroduce pressurized air to the reservoir 20.
Air is supplied to disinfectant bottle assembly 62 through pressure regulator
63. When valve 65 is in the "DISINFECTANT" position G, the disinfectant
manifold
66 is charged to deliver the disinfectant solution as required. For example,
with valve
65 in this position and with valve 54 in the "DISINFECTANT" position D,
disinfectant is supplied to the high speed drill 4 through master block 51. In
this
manner, the high speed drill 4 can be flushed with the disinfectant solution
while at
the same time, syringe 6 can be supplied with water from port 74 of water
manifold
50 when valve 56 is in the "WATER SUPPLY" position F.
In order to purge the system with disinfectant solution, selector valve 49 is
set
to the "DISINFECT FLUSFf" position B. This shuts off the water supply from the
utility module 41. Valve 65 is set to the "DISINFECTANT" position G.
Disinfectant
solution in manifold. 66 charges water manifold 50 through valve 49. This
expels
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disinfectant fluid through all tubing and devices connected to the water
manifold 50.
In this operation, valve 54 is set to the "WATER SUPPLY" position C and valve
56 is
set to the "BLOCK: SUPPLY" position E. Syringe block 8 is also flushed with
disinfectant during this procedure. Valve 56 is toggled to the "DIRECT SUPPLY"
position F to expel water from the tubing connected from port 74 in the water
manifold 50.
All tubing is then charged with disinfectant solution which is preferably left
to
stand over night. 7.'o flush the system of the disinfectant solution, valve 65
is set to
the "WATER SUPPLY" position H and valve 49 to the "WATER SUPPLY" position
A. Valve 54 is set to the "WATER SUPPLY" position C. Valve 56 is set to the
"BLOCK SUPPLE"' position E. Toggling valve S6 to the "DIRECT SUPPLY"
position F purges the disinfectant from port 74 and the tubing to valve 56.
Toggling
valve 54 to the "DISINFECTANT" position D purges the disinfectant from the
disinfectant manifold 66 and the tubing that connects outlet port 84 to valve
54.
In a further preferred embodiment, illustrated in Figures 4 and 5, the
sanitizing
tank 114 comprises a pasteurizing system comprising a conventional heating
element
116, which heats tree water to a predetermined temperature, preferably at
least 82
degrees C ( 180 degrees F) as measured by a temperature sensor 117, in order
to
sterilize the water. The sanitizing tank 114 is hermetically sealed, and a
check valve
118 is preferably provided upstream of the sanitizing tank 114 to prevent
backflow
into the municipal water supply. In this embodiment also the sanitizing tank
114
preferably has a removable lid (not shown) which can be removed to permit
thorough
disinfecting and clf;aning.
In the operation of this embodiment, the heating coil 116 is preferably
activated a preset time, for example 30 minutes, after the sterilizing tank
114 is filled.
The temperature sensor 117 detects the temperature of the water within the
sterilizing
tank 114 and communicates a signal to close switch TS 1 and activate the
heating coil
116, to heat the water in the sterilizing tank 114 to the desired sterilizing
temperature
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(eg. 180 degrees F). Once the preset sterilizing temperature has been reached,
and
preferably maintained for thirty minutes, switch TS 1 is opened and the
sterilized
water is permitted to cool for use. When the sterilized water has cooled to
the desired
use temperature (eg. 68 degrees F), switch TS2 closes to open solenoid valve
132 and,
so long as high level sensor 128 is not indicating that the reservoir 120 is
filled to the
upper limit, allow tine sterilized water to drain from the sterilizing tank
114 into the
reservoir 120.
When the lower limit of the water level in the reservoir 120 is detected by
the
lower limit sensor 130, solenoid valve 140 is closed to shut off the water
supply to the
dispensing apparatus (not shown). If the temperature sensor 117 indicates that
sterilized water in the sterilizing tank 114 has cooled to the preset use
temperature,
solenoid valve 132 is opened to allow the sterilized water to drain from the
sterilizing
tank 114 into the reservoir 120. When the high level sensor 128 is activated,
the valve
132 closes and flow from the sterilizing tank 114 to the reservoir 120 is cut
off. Thus,
the batch of water in the reservoir 120 is always sterile and at the desired
use
temperature. It is preferred that sanitizing tank 114 is sized to sanitize or
pasteurize
only one batch of water per day. The system should be drained and cleaned at
the end
of each day.
While the water sanitizing system of the invention is advantageously utilized
in conjunction with the water dispensing system 2 of the invention or another
water
distributing or dispensing apparatus for dental procedures, it will be
appreciated by
those skilled in the ;art that the utilization of this system is not limited
to dental
applications. The invention may also be utilized in industrial, research and
medical
facilities where clean water is required in large quantities. Based on the
design of this
sanitizing system, capacities for widely varying amounts of required water may
be
readily accommodated.
Preferred embodiments of the invention having been described herein by way
of example, other n:~odifications and adaptations will be apparent to those
skilled in
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the art. The invention includes all such modifications or variations as fall
within the
scope of the appended claims.
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