Note: Descriptions are shown in the official language in which they were submitted.
10;16846
This invention relates to dentistry and more particularly to an
improved apparatus for removing tooth caries and plaque.
The present application is a divisional of Canadian application
Serial ~o. 173630, filed June 8, 1973.
In my United States Patent 3,932,605, issued on January 13, 1976,
there is disclosed a dental treatment for removing caries and preparing teeth
for filling in which the teeth are brought into contact with an N-haloamine
solution without the necessity of using drills or like. The treatment is
also disclosed as being useful in removing plaque.
The present invention is concerned with improvements in the appli-
cation of the aforesaid solutions to the teeth whereby a much more rapid and
effective caries removal can be accomplished through a combined mechanical
and chemical action.
One of the disclosed methods of applying the chemical solutions
recited in the aforesaid patent is by the use of a WATER PIC device (see
United States Patent No. 3,227,158). These devices are known in the art for
use in oral hygiene - cleaning of teeth, massaging gums and for plaque remov-
ing. A device of this type embodies structure operable to deliver a water
jet stream pulsating at 800 to 1600 cycles per minute at maximum pressure 90
pounds per square inch through a jet orifice of 0.025 to 0.0~5 inches in
diameter.
While the present invention is particularly concerned with the
improvements in delivering the aforesaid chemical solution to teeth for caries
and plaque removal, the invention may likewise be viewed as an improvement
in the aforesaid apparatus for applying water to the teeth for oral hygienic
purposes such as plaque removing, teeth cleaning and gum massaging.
In accordance with the principles of the present invention a signi-
ficant improvement in obtaining a rapid and effective debris removal from
teeth is obtained by modifying the above-mentioned pulsating jet stream so
that in each pulse cycle the difference between the highest pressure and a
- 1 - `;~
1036846
lowered pressure applied to the material and the respective perioas for
which the material is under highest pressure and lowered pressure causes the
material to be mechanically stressed and then completely relaxes so as to
establish an erosion by fatigue which materially enhances caries removal.
An object of the present invention is the provision of an improved
apparatus for caries removal in preparing teeth for filling which eliminates
the need for drills and the like and operates in accordance with the princ-
iples enunciated above.
Another object of the present invention is the provision of an
improved apparatus of the type described operable to remove plaque from
teeth. Accordingly, the invention provides apparatus for removing dental
debris comprising a jet forming means, a liquid pump having an inlet and an
outlet communicating with said jet forming means, a container for bulk supply
of liquid, non-return valve means providing a communication between said
container and said pump inlet, a flexible hose forming a communication bet-
ween the pump outlet and said jet forming means, a flow control valve for
said ~et forming means, and means for repeated operation of the pump such
that in each cycle of operation there is a period of application of pressure
feed followed by a period of non-application of pressure feed, said pump
operating means comprising a prime mover, a rotary cam coupled for driving
by the prime mover, a cam follower positioned to be abutted by the rotary
cam, means coupling the cam follower to a moving element of the pump, means
`; coupled to the cam follower for effecting its return stroke, and adjustable
means for limiting the return stroke of the cam follower thereby to permit
variation of the working stroke of the pump.
It has also been found that caries and plaque removal can be
further facilitated by the application of ultra-sonic vibration to the pul-
sating jet stream both when used with the aforesaid chemical solution to
supplement the chemical action thereof as well as the oral hygienic action
of a pulsating water jet stream.
1036846
Another embodiment of the invention pro~ides apparatus of the type
described additionally having means for imparting ultra-sonic vibrations to
the pulsating Jet nozzle so as to both enhance the material removing effect
of the pulsating liquid jet stream and the material removing capability of
the nozzle itself when brought into contact with the material to be removed
during operation.
The invention may best be understood with reference to the accomp- -
anying drawings wherein an illustrative embodiment is shown.
In the drawings:
Figures 1 and 2 are graphs to show the time-pressure relationship
of pulsed liquid streams used currently in the art;
Figures 3 to 6 are graphs to show the time-pressure relationship
of certain pulsed liquid streams which were investigated during the making of
the present invention;
Figures 7 and 8 are graphs showing the time-pressure relationship
of pulsed liquid streams in accordance with this invention;
Figure 9 is a diagrammatic representation of a fiber to show its
reaction to being stressed by a pulsed liquid stream in accordance with Figures
1 to 6;
Figures 10 and 11 are diagrammatic representations of a fiber to
show its reaction to being pressed respectively by the pulsed liquid streams
in accordance with Figures 7 and 8;
Figure 12 is a side elevational view of a variable flow pump mechan-
ism for producing pulsed liquid streams in accordance with Figures 7 and 8;
Figure 13 is a fragmentary end view of a modified form of cam and
cam follower arrangement;
Figure 14 is a fragmentary front elevational view of a cam and cam
follower arrangement shown in Figure 13;
Figure 15 is a schematic diagrarn of a complete assembly of apparatus
for generating and applying the improved pulsed liquid jet stream of the
~0368~6
present invention; and
Figures 16 and 17 are graphs to show time-pressure relationships
of an undesirable nature arising from too high a frequency and/or too low a
capacity of nozzle opening.
It is known to utilize a pulsating high velocity jet stream of
liquid as a means for cleansing of the mouth. It has not hitherto been poss-
ible to effect complete removal of caries. It was found and it is an object
of this invention, that caries can be removed and teeth prepared for filling
if a solution of N-haloamine acid at pH between 10.5 and 11.5 is delivered on
a carious area as a pulsating liquid jet stream; the same can be used for
plaque removal, however, the chemical action is only improving the effect
while for removal of caries chemical effect is necessary.
In accordance with the invention it has been found that the shape
of the time-pressure relationship curve of the jet stream pulsations is a very
important factor, much more so than frequency and pressure. By selection of
a suitable time-pressure curve, there is introduced a period for complete
relaxation of the attacked material, between each pulse.
In the accompanying drawings, Figures 1 and 2 show the time-pressure
curve of the prior art method and apparatus, whereas Figures 3 to 6 show
other such curves which are obtainable. Figures 7 and 8, in contrast, show
curves in which there is zero application of pressure to the material for a
prolonged period between each pulsation.
The pulsating jet streams represented by Figures 3, 4, 5 and 6 are
far less efficient than the streams represented by Figures 7 and 8, and the
best results are obtained with the stream shown on Figure 7. While all the
pulsating jet streams represented by Figures 1 to 6 cause stress changes in
the material being treated, they do not allow for its relaxation, not even
the streams represented by Figures 1, 3 and 4, wherein the pressure keeps
dropping to zero with each cycle, because the time allowed at zero pressure
is infinitesimal. Complete relaxation of the material requires a certain
1036846
period of time, according to its elasticity. On the other hand, the time
element involved in a period of applying of stress is incomparably shorter.
As a means of showing changes of shape of a stressed material under applied
pressure, an elastic fiber can be used. Pulsating liquid jet streams repres-
ented by Figures 1 to 6 will cause vibrations, of a fiber in the manner shown
in Figure 9, whereas jet streams represented by Figure 7 or 8 will allow, due
to the presence of a proper relaxation period, much larger vibrations, as
shown in Figures 10 and 11. A similar phenomenon occurs of solid elastic
material such as dental plaque or caries. These materials are therefore
efficiently eroded in depth, fatiguing in a relatively short period of time
(seconds for plaque, minutes for caries), and therefore these materials can
be removed by erosion, rather than by hydrodynamic abrasion. Since the
elastic properties of dental materials differ from case to case, it is desir-
able to provide flexible equipment, allowing for adjustment to the most
efficient frequencies and pressures, both independently. The existing devices
do not allow for independent adjustment of frequencies and pressures, nor do
they allow for ad~ustment of the time element allowed for stress and relax-
ation within a cycle.
Referring now more particularly to Figure 12, there is shown therein
a device, generally indicated at 10, for producing a pulsed liquid jet stream,
with time and pressure variable to permit the formation of the characteristic
curves of Figures 7 and 8. As shown, the device 10 includes a fixed frame
structure 12, which may be of any conventional construction, suitably config-
ured to support a container or receptacle 14 for the liquid supply and a
power driven pump mechanism, generally indicated at 16, for delivering the
supply of liquid contained within the receptacle 14 to a discharge nozzle 18
which, as shown, is in the form of a hypodermic needle.
The pump mechanism 16, as shown, is preferably of the flexible
diaphragm type, although it will be understood that piston and cylinder types
as well as flexible bellows types may be utilized if desired. As shown, the
10368~6 .
pump mechanism includes a pump body 20 of a suitable heat conductive material,
such as metal or the like, defining an open ended pump chamber 22 disposed
with its axis extending generally hori~ontally. The open end of the pump
chamber 22 is closed by flexible diaphragm 24, formed of any suitable resil-
ient or flexible material such as rubber, plastic or the like.
Embedded within the central portion of the diaphragm 24 and extend-
ing axially outwardly therefrom is a plunger rod 26. Fixedly connected to
the rod 26 at a position adjacent the diaphragm 24 is the central portion of
a cross-head plate 28. The ends of the plate 28 are apertured to guidingly
receive therein a pair of guide rods 30 suitably fixed to the frame structure
12 in parallel relation to the plunger rod 26. The plunger rod 26 and diaph-
ragm is resiliently urged into an outward limiting position, as shown, by
suitable spring means such as a pair of coil springs, 32, disposed in surround-
ing relation to the guide rods with the ends thereof abutting the cross-head
plate 28 and frame 12 respectively.
Movement of the plunger rod 26 and diaphragm 24 away from and toward
the limiting position in successive cycles of operation is accomplished by
a cam and cam follower assembly which, as shown, includes a cam follower arm
34 pivoted at one end to the frame structure 12, as indicated at 36, and having
its central portion disposed in abutting engagement with the outer end of
the plunger rod 26. Disposed on the side of the central portion of the cam
follower arm opposite the plunger 26 is a cam 38 fixed to a shaft 40 driv-
ingly connected to the output shaft of a variable speed electric motor 42
suitably supported on the frame structure 12. The end of the cam follower
arm 34 opposite from the pivot 36 is disposed in a position to abut an adjust-
ment member 44 suitably threaded on an elongated member 46 which is either
fixed to the frame structure or forms a part thereof. A lock nut 48 is also
threaded on the member 46 to retain the adjusting member in any desired
position of adjustment along the member 46.
Figures 13 and 14 illustrate another cam and cam follower arrange-
1036846
ment which could be utilized in lieu of the arrangement described above. As
shown in Figures 13 and 14, the end of the plunger rod 26 is bifurcated, as
indicated at 50, and has a cam follower roller 52 journaled therebetween. A
cam 54 is keyed to the shaft 40 in such a way as to be movable axially with
respect to the shaft. The cam 54 is constructed with different axially
spaced continuous contact cam surfaces 56, 58 and 60, any one of which can
be brought into contact with the cam follower roller 52 by adjusting the
axial position of the cam 54 on the shaft 40. Such a continuous contact cam
drive has a lower noise level and may be made more durable than the inter-
mittent drive of Figure 12.
It will be understood that both of the above arrangements provide
the operator with the capability of adjusting the dwell time of each cycle.
A fixed performance device however, may be desirable from the standpoint of
economics and is thus contemplated by the present invention in its broadest
aspects.
In order to enable the cycling of the pump mechanism 16 to deliver
the supply of liquid in container 14 through the nozzle lô as a pulsating jet
stream, an inlet tube 62 having a check valve 64 therein is connected between
the bottom of the container 14 and an inlet opening formed in the bottom of
the pump chamber 22 and an outlet tube 66 is connected between an outlet
opening formed in the top of the pump chamber 22 and one end of a hollow
handle portion 68, the opposed end of which has the hypodermic needle nozzle
18 extending therefrom.
With the variable arrangement shown, adjustment of the stop
member 44 accordingly adjusts the angular stroke of the cam follower arm 34,
and thus also the stroke of the diaphragm 24. The period of time during which
the cam 38 contacts the lever arm 34 corresponds to the pulse of Figures
7 and 8, and the period when the cam 38 is not contacting the arm 34 corres-
ponds to the relaxation period of Figures 7 and 8.
Another feature of this assembly is that the pump is preferably
~0~68q6 ~
equipped with one check ~alve 64 only on the inlet line. Nevertheless,
check valves on both the inlet and the outlet may be used. Another feature
of the present arrangement is that the forcing stroke is caused by the motor
driven eccentric, whereas the springs cause the suction stroke. An eccentric
or cam principle may be used instead of such springs, and the pump may be
driven by a pair of cams-eccentrics, one serving for the driving stroke and
the other for the suction stroke, but both being engaged part of the revolu-
tion only, making the stroke sharp and allowing the pump to be motionless
for part of the revolution. One revolution in any case must represent then
one full cycle.
A complete apparatus for the production and application of a pulsed
liquid ~et stream, in accordance with the invention, is shown in Figure 15.
It consists of the device 10, as previously described, with an electric
heater element 70 and thermostatic control 72 embedded in the pump body 20,
to maintain body temperature in the liquid. The motor 42 is controlled by an
on and off foot switch 74. The foot switch 74 may be combined with an rpm
regulator, if desired. The valves used are preferably ball valves. The
flexible tube or hose may conveniently be of 3/16 - 1/4 inches inside diam-
eter and preferably spring coil reinforced in order to avoid absorbing of
the pulsation. The elasticity of the hose can cause some absorption, and
therefore the pulsation stream is inclined to be of the shape as in Figure 8.
Stroke frequency, pump capacity and nozzle opening are desirably in balance.
Too high a frequency and/or capacity for too small a nozzle opening may cause
undesirable changes in the shape of a pulsed stream - see Figures 16 and 17.
The undesirable dental caries materials differ in mechanical properties from
case to case and the following ranges were found practical:
1. Nozzle diameter - hypodermic needles gauge 33 to 10.
2. Frequency 100 - 1600 cycles/min.
3. Motionless period of the pump 50-95% during one cycle.
4. Flow rates 15 to 200 ml per minute.
1036846
5. Pressures 10 to 400 psi at the peak.
It was also found that a jet stream shown in Figure 16 or 17 is
applicable on harder materials if according to:
a) Figure 16: A-B (maximal A=50%) for C-1/3D
(Maximal C=33% of D)
b) Figure 17: A-B and C-1/3D
It was also found practical to use water, or water solution of
different pH, preferably at body temperatures, for treatment.
EXAMPLE 1
Teeth cleaning - plaque removal
Motionless Peak Liquid
TimeFrequency Period Nozzle Pressure Flowrate Medium
15 min. 400 85%21 gauge115 psi 80 ml/min. Water
12 min. 150 50%15 gauge65 psi 120 ml/min. Water
10 min. 650 90%21 gauge120 psi 60 ml/min. Water
14 min. 1200 95%33 gauge300 psi 75 ml/min. Water
11 min. 1600 95%20 gauge160 psi 200 ml/min. Water
12 min. 600 92% 20 gauge 110 psi 55 ml/min.Solution A
12 min. 650 90% 21 gauge 115 psi 55 ml/min.Solution B
8 min. 550 75% 14 gauge 50 psi 35 ml/min.Solution B
10Solution A
NaOH 0.05 moles/liter
NaCl 0.05
Glycine 0.05 "
Water as a solvent
Resulting pH 11.1
Solution B
As above with addition of 0.008 moles of NaC10 per liter
Resulting pH 11.4
-
1036846
EXAMPLE 2
A decayed tooth prepared for filling
Motionless Peak Liquid
TimeFrequencyPeriod Nozzle Pressure Flowrate Medium
5.5 min. 250 80% 20 120 psi 65 ` Solution B
4 650 90 21 90 47 "
12 150 50 109 60 40 "
11 800 95 21 95 48 "
14 1200 95 20 135 57 "
2.5 5 85 20 85 30 "
7 500 90 23 90 25 "
8.5 350 50 18 70 35 "
While effective results are obtained with the apparatus as thus
far described and exemplified above, these results were enhanced by further
including in the apparatus, as shown in Figure 15, a transducer 76 mounted
on the handle 68 and electrically connected to an oscillator 78 for producing
a desired ultra-sonic frequency.
The liquid Jet is aimed to the tooth through the nozzle 18. The
nozzle may be a tapered metal cylinder with a knurled surface for controlling
the pulses. Disposable hypodermic needles may be used in the nozzle. The
use of a needle as an orifice is desirable since it allows the pulse to be
aimed at hard-to-reach areas in the mouth and the dentist can scrape at the
caries or plaque as the liquid jet is applied. Since the nozzle may often
become clogged with plaque or other material it should be easy to exchange
nozzles.
In a practical embodiment for dental plaque and caries removal,
the following operating conditions were used:
1. Pressure - between 10 and 400 psig.
2. Liquid flow rate - 20-150 ml. per minute.
3. Nozzle diameter - 15 to 30 gauge hypodermic
needles used.
4. Operating temperature - 35 to 45 C preferably
body temperature.
-- 10 --
1036846
5. Pulse frequency - 100 to 1600 pulses per
minute.
6. Dwell - 50-90% of the cycle.
For the ultra-sonic generator attached to the nozzle, the frequency
used is preferably between 5 - 75 KHz, preferably 20-25 KHz, and the energy
output 5 to 50 watts. Ultra-sonic vibrations increase the efficiency of
the liquid Jet and also improve the mechanical action of the nozzle. In
operation, the nozzle may be used to scratch out the loose particles, and
the ultra-sonic vibrations are found to make this operation very efficient.
According to the invention disclosed in my United States Patent
No. 3,776,825, issued December 4, 1973, a solution of an alkali metal or an
alkaline earth metal halide is decomposed electrolytically so as to provide
free halogen which then reacts to form hypohalite in the presence of hydroxide
ion. In order to form an N-halo derivative, the starting solution should
also contain a suitable amino compound or compounds. The hypohalite reacts
to form an N-halo derivative as soon as it is formed in the solution.
The starting solution may contain one or more alkali metal or alka-
line earth metal halides.
Examples of suitable starting halides are sodium chloride, sodium
bromide, sodium iodide, lithium chloride, lithium bromide, lithium iodide,
potassium chloride, potassium bromide, potassium iodide, rlbidium or cesium
chloride, calcium chloride, calcium bromide, calcium iodide, strontium chlor-
ide, strontium bromide, strontium iodide, barium chloride, barium bromide and
barium iodide.
The solution formed should have an alkaline pH usually 8 to 12 and
preferably 10.5 to 11.5, most preferably 11 to 11.5. Desirably the electro-
lysis is carried out to form a solution 0.00~ to 0.016 molar in N-haloamine.
While not essential it is preferable to have present excess unhalogenated
amine, i.e., in an amount up to 15 times the halogenated amine and preferably
6 to 8 times the N-halogenated amine on a molar basis.
-- 11 --
1036B46
As the amino nitrogen compounds there can be used either inoreanic
compounds such as sulfamic acid or organic compounds containing 2 to 11
carbon atoms, e.g., glycene, sarcosine, alpha-aminoisobutyric acid, taurine,
2-aminoethanol, N-acetylglycine, alanine, beta-alanine, serine, phenyl alanine,
norvaline, leucine, isoleucine proline, hydroxyproline, omega aminoundecanoic
acid, glycylglycine, glycylglycylglycine, (and other polypeptides) aspartic
acid, glutamic acid, glutamine, asparagine, valine, tyrosine, threonine,
methionine, glutamine, tryptophane, histidine; arginine, lysine, alphaamino-
butyric acid, gammaaminobutyric acid, alpha, epsilon diamino pimelic acid,
ornithine, hydroxyl lysine, anthranilic acid, p-aminobenzoic acid, sulfanilic
acid, orthanilic acid, phenyl sulfamic acid, aminopropanesulfonic acid,
2-aminoethanol, 2-aminopropanol, diethanolamine, ethylenediamine tetraacetic
acid (EDTA), nitrilotriacetic acid and aminomethanesulfonic acid.
Examples of mona N-halo compound include N-chloroglycine, N-
bromoglycine, N-iodoglycine, N-chlorosarcosine, N-bromosarcosine, N-
iodosarcosine, N-chloro alpha amino isobutyric acid, N-chlorotaurine, N-
bromotaurine, N-iodo taurine, N-chloro ethanolamine, N-chloro-N-acetyl
glycine, N-bromoethanol amine, N-iodoethanolamine, N-iodo -N-acetyl glycine,
N-bromo N-acetyl glycine, N-chloroalanine, N-chloro beta alanine, N-bromo
beta alanine, N-chloroserine, N-bromoserine, N-iodoserine, N-chloro-N-
phenylalanine, N-chloroisoleucine, N-chloronorvaline, N-chloroleucine, N-
bromoleucine, N-iodoleucine, N-chloroproline, N-bromoproline, N-iodoproline,
N-chloro hydroxyproline, N-chloro omega aminoundecanoic acid, N-chloroaspartic
acid, N-bromoaspartic acid, N-chloroglutamic acid, N-iodoglutamic acid, N-
chlorovaline, N-chlorotyrosine, B-bromotyrosine, N-iodotyrosine, N-chloroth-
reonine, N-chloroglycylglycine, N-chloroglycylglycylglycine, N-chlorometh-
ionine, B-bromomethionine, N-chlorotryptophane, N-chlorohistidine, N-
chloroargenine, N-chloroglutamine, N-bromoglutamine, N-chlorolysine, N-chloro
gamma aminobutyric acid, N-chloro alpha, epsilon diaminopimelic acid, N-chloro
ornithine, N-chloro hydroxylysine, N-chloroanthranilic acid, N-chloro p-
~036846
aminobenzoic acid, N-chlorosulfamic acid, N-chloro phenylsulfamic acid,
N-chloro aminopropanesulfonic acid, N-aminomethanesulfonic acid, N-chloro-
propanolamine, N-chlorodiethanolamine, N-chloro ethylene diamine tetraacetic
acid.
The solutions below may be prepared by the above- described
electrolytic method to form the haloamines.
Solution (moles in a liter of a water solution)
A NaC1 NaOH Amino Compound
.
0.10 o.o8 0.05 glycine
B KCl KOH
0.15 0.08 0.05 taurine
C LiBr LiOH
0.15 o.o8 0.05 elycine
D NaI NaOH
0.10 0.12 0.10 sulfamic acid
E CaC12 NaOH
0.10 0.07 0.05 glycine
F NaCl NaOH
0.10 o . o8 0.025 glycine
0.025 taurine
As set forth in my United States Patent No. 3,932,605, issued
January 13, 1976, the teeth are brought into contact with an N-haloamine also
containing a hydroxy group, a sulfonic acid group, an N-acyl group, e.g. an
N-acetyl group, or a carboxylic acid group. The halogen has an atomic weight
of 35 to 127. Unless otherwise indicated in the present specification and
claims the term "N-halo" means "N-monohalo".
Many of the N-halo compounds are unstable and they are conveniently
prepared by reacting an alkali metal or alkaline earth metal hy~ohaline,
preferably hypochlorite, with the arnino compounds.
Examples of suitable hypohalites include sodium hypochlorite,
potassium hypobromite, sodium hypoiodite, potassium hypoiodite, potassium
hypobromite, rubidium hypochlorite, cesium hypochlorite, calcium hypobromite,
- 13 -
~036~46
strontium hypochlorite and barium hypochlorite.
For reacting with the hypohalite to form the N-halo compounds of
the invention there can be used any of the aminocarboxylic acids or amino-
sulfonic acids previously set forth. ~he N-halo compounds formed and used
in the present invention are those previously mentioned, e.g. N-chloroglycine.
Solution B employed in example 1 and 2 is an illustration of forming N-
monochloroglycine in situ from sodium hypochlorite and glycine.
Preferably there are employed N-halo amino carboxylic acids, e.g.
aminoalkanoic acids free of divalent sulfur or free of a heterocyclic ring
since when the divalent sulfur atom or the heterocyclic ring is present the
N-halo compound has a very short half life.
The N-bromo and N-ido compounds are the most effective but they
have shorter half lif`es than the N-chloro compounds and hence the N-chloro
compounds are usually employed. Preferably the N-halo amino group is directly
attached to aliphatic carbon atom compounds which have an unpleasant odDr
preferably are not employed.
In Goldman et al., United States Patent 3,886,266, issued May 27,
1975, there is disclosed the treatment of teeth to remove caries, dissolve
plaque and prevent the development or buildup of calculus by the use of
sodium, potassium or calcium hypochlorite at a pH of 9 to 11.5. Goldman
et al. disclose there can be used non-toxic buffering agents and states that
a preferred buffering agent is a mixture of glycine, sodium chloride and
sodium hydroxide and specifically shows a mixture of a O.5% solution of
sodium hypochlorite, 1% glycine hydrochloride and sufficient sodium hydroxide
to bring the pH to about lO . They also disclose adding a mixture of 1 ml
of` flavor, 98 ml of a buff`er solution O.O5 molar in glycine, O.05 molar in
sodium hydroxide and O.O5 molar in sodium chloride and 1 ml of 5% NaOCl to
5OO ml of water and making the product up to lOO0 ml with water. While
Goldman et al. did not realize it they were making N-chloro-glycine in situ
by this procedure and it was the N-chloro-glycine which was the active agent
- 14 -
1036846
in their process. Goldman et al. also disclose the use of a ~et of the
solution, e.g. from a mechanical pumping mechanism such as a WATER PIC.
The parent nitrogen containing compound is preferably used in
excess in forming the N-halo compound in situ from a hypohalite, e.g., the
molar ratio of the parent nitrogen containing compound to available X
(from the hypohalite) should be 1:1 or greater, and preferably in the range
of 2:1 to 15:1, most preferably 7:1. A mixture of nitrogen containing
compounds can be used.
The available active X concentration should preferably lie between
0.01% and 6%, and more preferably 0.05% and 1%.
The N-halo amine solutions should be used at a pH in the range of
pH 8 to 12 and more preferably in the range of pH 10.5 to 11.5 inclusive,
most preferably 11 to 11.5.
To maintain the preferred pH range it is desirable, because hydro-
gen ions are generated during the decomposition of an H-halo compound in
aqueous solution to add a buffer system to the solution. Such buffer should
be compatible with the N-halo compound, i.e. it should not have any deleter-
ious effect thereon and it should be non-toxic. Borates and phosphates are
examples of compatible salts for the formation of buffer systems, e.g.,
Na2 H P04 can be used as the buffer since it can hold the pH above 10 even
though in other systems it usually buffers at a lower pH.
Of course mixtures of N-halo compounds can be employed.
Unless otherwise indicated all parts and percentages are by weight.
Fcrmulations A - F below illustrate formin~ in situ N-haloamines
which are illustrative of those which are effective in the present invention.
Solutions used (Data are given in moles per liter of the water solution.)
~036846
Buffer
NaOOl NaOH NaCl Amino Compound Salt pH*
A 0.008 0.0539 0.050 0.05 glycine Na2HP04 11.59
0.0025
B o.oo8 o.o640 0.050 0.05 glyeine Na2B40710.77
0.00125
c o.oo8 0.0210 0.050 0.05 glycine Na2B407 9-65
0.00125
D 0. oo8 o . os37 o . 050 o . 05 sulfamic acid None 11.49
None
E o.oo8 0.0520 0.052 0.05 sulfamie acid None 10.75
None
F o.oo8 o.o548 0.050 0.05 taurine None 11.86
None
* The pH value of all solutions tested remained eonstant within 0.2 pH units
for at least one hour.
Less preferably there ean be used in the present invention N-
dihaloamino eompounds sueh a~ N-diehloroglyeine, N-dibromoglyeine, N-
diiodoglyeine, N-dichlorosarcosine, N-dibromosarcosine, N-diiodosarcosine,
N-dichloro alpha amino isobutyrie aeid, N-diehlorotaurine, N-dibromotaurine,
N-diiodotaurine, N-dichloroethanol-amine, N-diiodoethanolamine, N-dibromo
beta alanine, N-diehloro beta alanine, N-diehloroalanine, N-diehlorserine,
N-dibromoserine, N-diiodoserine, N-diehloroisoleueine, N-diehloronorvaline,
N-diehloroleucine, N-dibromoleueine, N-diiodoleueine, N-diehloroproline,
N-dibromoproline, N-diiodoproline, N-diehlorohydroxyproline, N-diehloro omega
aminoundeeanoie aeid, N-diehloroaspartie aeid, N-dibromoaspartic aeid,
N-diehloroglutamie aeid, N-diiodoglutamie aeid, N-diehlorovaline, N-
diehlorotyrosine, N-dibromotyrosine, N-diiodotyrosine, N-diehlorothreonine,
N-diehloroglycylglycine, N-dichloroglycylglycylglycine, N-dichloromethionine,
N-dibromomethionine, N-dichlorohistidine, N-dichloroargenine. N-dichloro-
glutamine, N-ditromoglutamine, N-dichlorolysine, N-dichloro gamna amino-
butyric acid, N-dichloro ornithine, N-dichloro hydroxylysine, N-dichloro
p-aminobenzoic acid, N-dichloro sulfamic acid, N-dichloro aminopropanesulfonie
~ 16 -
10368~6
acid, N-dichloroaminomethane sulfonic acid.
It thus will be seen that the ob~ects of this invention have been
fully and effectively accomplished. It will be realized, however, that the
foregoing preferred specific embodiment has been shown and described for the
purpose of illustrating the functional and structural principles of this
invention and is sub~ect to change without departure from such principles.
