DESCRIPTION

TECHNICAL FIELD:

The present invention relates generally to the field of automated medical and dental appliances, and more particularly to a system for disinfecting medical and dental unit wateriines (DUWL) which convey water to dental or medical implements or instalments for irrigation and/or cooling and to cuspidor drink cups. The predominant current usage of the antimicrobial flush system of this invention is to assist in disinfecting water lines in dental handpiece units used for dental cleaning and surgery.

BACKGROUNDART:

Modem dental handpiece units employ electricity for illumination, air for pneumatic power, and water for cooling and/or Irrigation, where a dental tool contacts teeth, bone or gums, and for drinking. The water supply can be provided either from city water or from a closed deionized or sterilized water system. However, in either system, once the handpiece or cup is replaced in a cradle after use, the remaining water in the feed lines, which are generally more than three feet long, and in the feed reservoirs and handpieces, stagnates. The water rapidly becomes contaminated by microbial populations, including bacteria, fungi and protozoa. Although the handpieces can be removed and sterilized, it has not been feasible to attempt to sterilize the feed lines except by laborious manual flushing.

It has been recognized that such microbial contamination is definitely a health hazard during surgical and dental cleaning procedures, due to the fact that patients and healthcare professionals are exposed to delivery of the contaminated water directly at the site of the surgical or dental procedure. This problem of dental unit waterline (DUWL) bacterial contamination is discussed in an article by

Andrews, N., Dental Unit Waterline Contamination, in Practical Hygiene, July/Aug. 1994, pp. 11-20. The problem Is significant, with DUWL bacterial populations frequently exceeding EPA and U.S. Army standards for potable water. Andrews concludes that flushing with water has proven unreliable at best, if any biofilm is present. Andrews also notes that biofilm is impossible to rule out. In addition to delivery of pathogens to patients and health care workers by direct contact (lavage) of open tissue, bacteria can also be communicated by aspiration of contaminated water, Inhalation of aerosol and ingestion (swallowing). The patients are not the only persons at risk. The scientific evidence suggests dental clinicians receive significant long term exposure to DUWL microbes. Indeed, there are anecdotal reports of DUWL microbial exposure contributing to the deaths of several dentists. Prior art efforts at addressing this problem have included the employment of closed water systems using sterilized water. However this is a less than suitable or long term remedy, since the environment, principally tubing, through which the water is introduced and used is not sterile, and contamination will

eventually occur. Even relatively pure city water contains some bacteria. Thus, where city water is used in the system the problem is exacerbated and accelerated. Prior to the present invention, the only way to clean dental handpiece units has been to disconnect the delivery tubes and/or handpieces involved from the feed water supply, and then go through a laborious immersion disinfection procedure (for handpieces), and/or a laborious and unreliable procedure of introduction and passage of disinfecting fluids through the tubes. According to such methods, the degree of cleansing depends upon the competence of the personnel doing the cleaning and the cleaning schedule and adherence thereto. Under the time constraints of modern dental practice, the procedure is often shortened or becomes infrequent, if not omitted entirely. In addition to the usual dental drills, syringes and drink cups, ultrasonic sealers are in wide use in dental offices to remove calculus, old cement, tartar stains, etc. These units also employ a water flow system to keep the tip cool, flush the work area, and assist in transmission of ultrasonic frequency energy. They are employed below gum line, e.g., in cases of gingivitis, abscesses, root canal work, etc. Accordingly, microbial populations developing in the lines of these units, e.g., between periods of use (stagnation), can be delivered to open tissue.

Likewise, there are non-ultrasonic sealers and air polishing units, which use a combination of air, water and abrasive to clean and polish teeth. These also require water and airlines, which can become stagnant and in which the DUWL microbes develop.

Manual flush systems are currently available from: Forest Dental, Hillsboro, OR; Ampco Dental, Grover City, CA; Adec Dental Manufacturing, Newberg, OR; Dental Components, Inc. (DCI), Newberg, OR; and PROMA, Carson, CA, among others. Even with such manual systems, poor, inconsistent or intermitted operations result in development of a film-like coating on the insides of the lines, called a "biofilm," a consortium of microbial populations in an acellular nutrient slime matrix. Such a thick slimy film can be partially broken free from the lines with high pressure water or air and comes out of the lines as a paste. In some cases, the lines become completely plugged.

Accordingly, there is a need for a simple system that is low in cost, simple to operate, and relatively fool proof, and which can be automatically cycled at the end of or before dental procedures, and/or cycled automatically according to a regular schedule.

DISCLOSURE OF INVENTION

OBJECTS AND ADVANTAGES:

It is among the objects and advantages of the present invention to provide an antimicrobial flush system (AMB Flush System) for medical/dental instruments, particularly dental handpieces, which system is automatic and easy to operate and may be retrofitted to current dental units. Other objects and advantages of the invention include providing: 1) an antimicrobial flush system which can be cycled at the beginning and/or at the end of every procedure; 2) an AMB Flush System which has built in safeguards to prevent misuse, and may be dedicated to service a single dental chair unit or medical station, or a single larger system can be hooked in parallel via a manifold system to a plurality

of dental chair units in one dental or medical office; 3) several alternative embodiments of an AMB Flush System for dental/medical instruments, particularly handpiece units and sealers, embodiments of which include both a pneumatic valve actuated system and an electrically controlled system; 4) an automatic AMB fluid line flush system for medical and dental handpieces, sealers and surgical tomes, which flush system can be manually initiated and or placed on a timer such that fluid feed lines to and from a handpiece can be flushed automatically, intermittently or at will; 5) a multi step process for sterilizing the internal lines of medical/dental devices which process not only reduces contamination but also aids in preventing further microbial growth during periods of non use; 6) a system for flushing dental medical instruments that is easy to initiate and complete, and does not depend upon the diligence or the skill of the operator; and additional objects and advantages are apparent from the following detailed description, drawing and appended claims.

The objects and advantages of the present invention are accomplished by the inventive system and method which includes means and steps for the internal sterilization of liquid lines in medical and dental instruments, particularly the water lines in dental handpiece and sealer units (herein "dental units"). The method comprises steps in one or more cycles including a PM (evening) cycle and an AM (daytime) cycle which may be employed separately or sequentially. The PM cycle steps include: Flushing the lines with a disinfectant solution for a timed period or volume; then flushing with fresh, preferably sterile, water for a timed period or volume; and finally keeping microbes from forming by flushing or evacuating the lines with a compressed gas, preferably air, or by vacuum suction, either continuously or at least until the lines are substantially dry. The AM cycle includes the steps of flushing with disinfectant, followed by rinsing with water.

Optional additional steps include repeat flushing of the lines with the disinfectant solution and then with water or other reuse media. Aspects of the method include a positive safety lock-out mode which prevents interruption of the method at steps wherein it would be undesirable to use the dental unit immediately following such step, and/or for preventing the use of the dental unit while the flush procedure is in progress, and/or to prevent disinfectant solution from reaching the patient. The method further preferably includes requiring the AM cycle to be completed at the beginning of a use period, e.g., in the morning, so as to prepare the system for use, even after a prior day's disinfecting procedure, i.e. after the PM cycle had been done the evening before. The system apparatus has, in both a first preferred embodiment and in a first equally preferred alternate embodiment: A pneumatically initiated indicator system to identify when the system is in operation and when the dental unit is in readiness; a pneumatically controlled valve system, including safety lock-out; manifold tubing, reservoir means and drain means. The system further has a unique pneumatic timing means for controlling the sequence of operation of the system. In a second equally preferred alternate embodiment of the invention, status indication is accomplished with indicator lights and valve operation is controlled electrically by solenoid operation, with the timing and sequence of operation being controlled by electronic means. Safety interlock means insure that the system is essentially "fool proof."

Principal alternatives include a special reservoir into which the handpiece hoses are inserted, alternative valve types, alternative timing means, and alternative disinfectant solutions such as aqueous solutions of alcohol, ozone, hydrogen peroxide, organic chemical biocides (such as Betadyne) and combinations (mixtures or sequences thereof). A conventional ozone generator/infuser such as a " DELZONE" ozone generator, is available from Del Industries, San Luis Obispo, California. The water also can be disinfected using ultraviolet irridation.

Anti-microbial flush systems of this invention can be employed with sealers and polishers. Examples of units to which this invention system apparatus can be connected include: Bobcat™ Ultrasonic sealer; Cavetron ¹ " Jet 30 combination cavetron unit and jet air (air/water/abrasive) polisher, Prophy-Jet™ 30 polisher, and Cavetron ^,M 3000 cavetron unit, all from Dentsply Co. of York, PA; and Autoscaler of Southeast Instruments of Miami, FL. The interconnection of the AMB Flush System of this invention to such sealers and air polishing is accomplished by adding a fitting (to U8, U9, or U10 below) and the accessory output line(s) (U3 or U5 below), and then connecting a line from the fitting to an air switch adaptor (ASA-2), and electrically connecting the air switch adaptor to the foot pedal of the sealer/polisher unit. Once the sealer/polisher unit is connected to power, and switched to the "on" position, the AM or PM buttons on the flush system of the invention will activate the sealer/polisher unit and automatically flush the unit's lines.

Thus, with such an air/electric switch air-value or solenoid, any water system can be controlled and flushed automatically by the AMB flush system of this invention. Indeed, the system of this invention is easily adapted to multi-chair, multi-dental unit operation by using simple parallel manifolding. The individual dental units can be individually activated for the flush cycle by appropriate selector valves.

Likewise, the system may be adapted for use in all cases where bacterial or microbial contamination is an interference or hazard. Examples include, but are not limited to: drinking water lines in school or public fountains, refrigerators, RV or camper vehicle or remote site potable water lines; food preparation water lines; cosmetology stations; painting; and other treatments or uses.

In an important alternative, a programmable timer is employed in conjunction with the control unit of the AMB Flush System of this invention. This timer permits the user, e.g., dental professional, to preset cleaning times so there are regular daily flush cycles. The PM cycle can be pre-programmed (preset) to start 15 minutes after close of business in the evening, and the AM cycle to start 5-15 minutes before start of business in the morning. Optionally, a midday (lunch hour) repeat of the AM cycle can be programmed. This timer preferably includes a battery backup. In addition, the entire electrical power for the AMB Flush System may be supported with a conventional gel-ceil type trickle charger to supply systems operating power during power outages.

A fluid flow water or biosensar can be employed in conjunction with the AMB Flush System control unit so that the bactericide, antimicrobial flush agent or disinfectant can be metered by volume, or the microbial content digs can be assessed as a function of flushing, or a combination of both, and the disinfecting step(s) of the cycle terminated open a preset volume flow or reaching a preset low bacterial/ microbial content threshold.

BRIEF DESCRIPTION OF DRAWINGS:

The invention is illustrated in more detail in the drawings in which:

Figure 1 is an isometric schematic view of a dental chair and related apparatus showing a typical installation of the antimicrobial flush system of this invention;

Figure 2 is a schematic diagram showing relevant portions of a prior art dental unit with which the present invention can be used;

Figure 3 is a flow chart depicting a flush process of the present invention;

Figure 4 is a diagrammatic representation of a preferred embodiment of an AMB Flush System according to the present invention;

Figure 5 is a diagrammatic representation of a first equally preferred alternate embodiment of the present invention;

Figure 6 is a cross sectional plan view of a pinch valve as used in the first equally preferred alternate embodiment of the invention; Figure 7 is a diagrammatic representation of a second equally preferred alternate em bodiment of the present invention;

Figure 8 is a schematic of an electronic control portion of the second equally preferred alternate embodiment depicted in Figure 7; and

Figure 9 is a perspective view of a reservoir bottle employed in the system of this invention.

BEST MODE(S) FOR CARRYING OUT THE INVENTION:

The following detailed description illustrates the best mode(s) of the invention by way of example, and not by way of limitation of the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what the inventor presently believes to be the best mode for carrying out the invention. In the figures discussed below the 300 series numbers refer to Fig.3, the 400 series to Fig. 4 and 5, 500 to Fig.5, 600 to Fig. 6, 700 to Fig.7, 800 to Fig.8 and 900 to Fig.9. A dental delivery system is illustrated schematically in Fig. 1, which includes a standard dental chair 1 and a dental unit 2 appurtenant thereto. The dental unit 2 is a conventional distribution control device such as is commonly used today in dental offices for providing and controlling feed of air, light, water, and, optionally, low voltage electricity for a variety of functions, or for some more narrowly defined specific function such as abrasive cleaning. The dental unit 2 may be placed at any of a variety of locations relative to the dental chair 1 , although it is usually desirable to place the dental unit 2 within easy reach of the dentist. Alternative known locations for the dental unit 2 (not shown for clarity) include mounting on a wall, the dental (patient) chair, a cabinet or on a mobile cart. The illustrative dental unit 2 generally has a syringe 3 and at least one handpiece 4 (three are shown in the example of Fig. 1), although

this arrangement is not strictly required. Indeed, other dental units (not shown) may include a different quantity of handpieces (not shown) and/or other variations. A foot control 5 is conventionally provided whereby the dentist may control operation of the handpiece 4 (as well as, perhaps, other functions). A plurality (one per handpiece 4)of handpiece hoses 6a-6c connect the handpieces 4 to the dental unit 2 and a syringe hose 6d connects the syringe 3 to the dental unit 2. The handpiece hoses 6a-6c and the three-lumen syringe hose 6d (air, water, drain) will generally differ in construction from each other, and such hoses may also vary somewhat in construction from application to application. These hoses generally deliver both water and air to the handpieces 4 and the syringe 3, and the handpiece hoses also generally deliver electrical power to handpiece connectors having intensity bulbs therein for illumination, suchasshownincopendingApplicationSN08 147,750fιled 11-4-1993, now U.S. Patent 5,476,397 issued December 19, 1995. The syringe hose may also include a drain line. Standard saliva ejector 6e and High Volume Evacuator (HVE) 6f are also suction (drain) lines. Drink cup water is supplied through line and spigot 6g. However, since the portions of these hoses 6a-6g which deliver air, vacuum and or electrical power are not discussed in detail herein, further references to these will be to the "hoses 6," and references to "flushing" or "running solution through" the hoses 6 will refer to those portions thereof which normally deliver water (as opposed to air, vacuum or electrical power).

A conventional junction box 7 provides a terminal point for which air, water, drain (as well as connecting vacuum and electrical supply lines, and the like) can be connected to the dental unit 2. These lines are shown schematically in Fig. 1 by dashed lines, identified, respectively, as: Electrical "E", Water "W", Air "A", Vacuum "V" and Gravity Drain "GD." An interconnection umbilical sleeve 8 is provided for housing the various air, electrical, water, drain and vacuum supply lines from the junction box 7 to the dental unit 2. An antimicrobial flush system control ("system control") 9 and an antimicrobial flush system indicator unit ("indicator unit") 10 are, combined, an example of the best presently known embodiment of the antimicrobial flush system (herein "AMB Flush System") of this invention 11. The flush system of the invention 11 can be located anywhere, but must be connected as close as possible to the water supply output, to ensure as much as possible of the chair/dental unit water system is treated, preferably all of it. Thus, although the AMB Flush System 11 may be located essentially anywhere along the interconnection hoses (or, conceivably, even at other locations), it is preferred to locate the system control 9 as near as is practical to the junction box 7 so as to treat the greatest possible portion of the hoses in the interconnection sleeve 8. It is also preferred to locate the indicator assembly 10 integral in the housing of the dental unit 2 such that it can be readily observed by the dentist, as is indicated of Fig. 1. Note in Fig. 1 the indicator assembly 10' can be separately mounted to the side of the dental unit 2, or elsewhere visible to the dental professional, e.g., on the post, cuspidor or light stand. However, it is not required that the AMB Flush System control 9 and the status indicator unit 10 be situated as shown in Fig. 1. Indeed, the system control 9 and the indicator unit 10 may be housed in a single unit comprising the AMB Flush System 11. The invention also comprises the AMB Flush System

11 included in combination with and housed within a modified or newly manufactured dental unit 2 (not shown).

Fig.2 is a schematic diagram of relevant portions of the dental.unit 2 and junction box 7 presented in Fig. 1. The syringe 3 is fed by a three-lumen syringe hose 6d, which includes line 6d-1 for air, 6d-2 for water and 6d-3 for drain. A selector block 13 has a plurality (three in the example of Figs. 2, 13A-13C) of handpiece connectors 14 (14A-C) for connecting handpiece hoses 6a (Fig.1) thereto, and a like plurality of selector valves 15 (15A-C) which automatically "select" the associated handpiece 4 (Fig. 1) connected to the selector block 13A, B or C for operation when that handpiece 4 (Fig. 1) is removed from the selector block 13. It should be noted that not all dental units 2 are so equipped, with some less expensive units having manual means for selection of the appropriate handpiece 4. When one of the handpieces 4 (Fig. 1) is thus selected, it is activated by the foot control 5. The syringe 3 must be drained (when the inventive AMB Flush System 10 is in operation, as will be discussed in more detail below) into a gravity drain line 6d-3 or into a cuspidor drain 16 where one is available, and/or through a vacuum line or vacuum drain (not shown). Where the drain hose 6d-3 is used, a drain valve 17 is used, and a "Y" fitting 18 may, in some applications, need to be fitted so that fluids can be diverted from the syringe 3 through the drain valve 17. A plurality of control valves and switches, generally numbered in three series 19A, B, C (six in the example of Fig. 2; valves 19A1-2 and 19B1-B3 and switch 19C), control and route water and air to the selector blocks 13A-C from the junction box 7. When the dental unit 2 is turned on by flipping switch 19C, pneumatic indicator 23 indicates the unit is "on." Thereafter, the AMB Flush System 11 may be operated by pushing power switch P, 718 (see Fig.7). in the junction box 7, air is input thereto through a main air valve 20 and water is input thereto through a main water valve 21. Although, as indicated in Fig.2, water will be provided from a city water supply, one skilled in the art will recognize that a closed water supply could also be used, with appropriate adaptations for providing a separate city water supply (not shown) to the cuspidor 16. A 'tap in' point 22 is an example of where the present invention AMB Flush System 11 might tap into the existing prior art junction box 7. Line 24 is the cuspidor drain.

Fig.3 is a flow chart depicting a general method 310 of flushing the lines and using the apparatus of the invention. According to the inventive method 310, the dental unit 2 (Fig. 1) will normally be in an operational state 311. When the user activates the master valve 415 (Fig. 4), or PV2/PV3515 (Fig. 5) or switch P, 718 (Fig.7) to turn on the AMB Flush System, foot control lockout valves 417 (Fig.4), 517 Fig. 5) or 720 (Fig.7) are closed preventing use of the dental unit 2. This is shown as "Turn On" step 312 for the AM cycle 323, and "Turn On" step 318 for the PM cycle 324. Then, when the user performs an " initiate AM " process step 313, the cycle proceeds automatically in sequence as follows: A first " flush system with solution" step 314, wherein the dental unit 2 is disinfected; then a first "flush system with water" step 315, wherein the dental unit 2 is flushed with water. The system then enters a "wait for operator intervention" hold mode 316, which enables the dental unit (DU) to be operated by the dental professional after turning off the AMB Flush System by repushing power button P, 718 (Fig.7). Thereafter, whenever master valve

V2415 (Fig.4), or PV2/PV3515 (Fig. 5), is closed, or switch P718 is opened, the dental unit 2 is enabled such that it may again be operated as indicated by reinstatement of the "dental unit ready for operation "311 status.

After AMB Flush System "Turn On" 317, when the user pushes the PM button on the console to begin the "initiate PM" step 318, the cycle 324 proceeds automatically, starting with a second "flush system with solution" step 319, wherein the dental unit 2 is disinfected; then to a second "flush system with water" step 320, wherein the dental unit 2 is flushed with water; then to a "flush system with air" step 322, wherein the dental unit 2 is flushed with air or the water flush evacuated by vacuum draw; and finally to "wait for operator intervention" state 321 , wherein the dental unit 2 water remains "locked out" until the user performs the " initiate AM " process step 313. When the " initiate AM " cycle 313 is initiated , the method 310 proceeds as previously related above. As can be seen in Fig.3, the method 310 is logically divided into two series of operational steps: an AM cycle 323, and a PM cycle 324.

Fig. 4 depicts the first preferred, pneumatic embodiment 11 of the AMB Flush System of this invention em ploying commercially available brass/ss (stainless steel) valves. Compressed air is introduced through an air input U1 412, passed via an intemal air tube 413 to an air regulator R2414 and thence to a master valve V2415 (shown as a toggle-type valve by way of example). When the toggle valve V2415 is operated (opened), air pressure is supplied simultaneously to: A) a valve V3 416; B) to a foot control lockout valve V13417 (which, as can be seen in Fig. 4, prevents air from being supplied from the foot control 5 when operated, thus "locking out" the operation of the handpiece(s) 4 of the dental unit 2); C) an indicator IND-1 418; D) an AM actuator valve V1 419; E) a PM actuator valve V8420; F) a signal valve V4 421; G) a signal valve V14 422; H) a signal valve V15 423; I) a purge air valve V10 424; J) a solution pressure regulator R1 425; and, K) through a check valve CV3426, a solution and/or sterile water reservoir 427. The solution and/or sterile water pressure regulator R1 425 is provided merely to prevent the over pressurization of the solution and/or sterile water reservoirs 427. Water is supplied to a water valve V7 428 and a water valve V11 429 from a water input 430.

When the AM actuator valve V1 419 is operated, air pressure is supplied, through a check valve CV8431 to a check valve CV1 432 and a check valve CV2433, to an expansion chamber C1 434 and an expansion chamber C2435, respectively, through Shuttle Tee ST-1 463, thereby opening a relief valve V12 436. Air pressure in the expansion chamber C1 434 passes through the emergency shutoff valve V3416, and opens a solution valve V6437 while closing the water vaive V7428. A precision needle valve NV1 438 slowly bleeds air pressure from the expansion chamber C1 434 at an adjusted, controlled rate, thereby determining how long the solution valve V6437 is open and the water valve V7428 is closed. Adjustment of the precision needle valves NV1 , 2 and 3 (438, 445 and 454 in Fig.4) act as a variable timer system for their respective accumulators C1 434, C2435 and C3449. Air pressure in the expansion chamber C2435 opens the signal valve V4421 and closes a routing valve V9 439. The signal valve V4 421 , when open, provides air pressure through an accessory port (union) U3440 to open the syringe drain valve V517 (Fig. 4). The signal valve V4421, when open, further provides air pressure through U3440, and then through

-β-

check vaive CV4442, opening the dental unit water coolant valve to the handpieces. The signal valve U4 421 opens one or more other accessory ports (unions) U2443 and U5444. The accessory port U2443 and the accessory port U5444 are provided for controlling equipment external to the AMB Flush System 11 , such as a second syringe (not shown), an air electric switch (not shown) or the like. U2443 or U5444 could be used in place of U3440 to control CV4442.

A precision needle valve NV2445 slowly bleeds air pressure from the expansion chamber C2435 at an adjusted, controlled rate, thereby determining how long the signal valve V4421 and the syringe drain valve V517 are open, and how long the routing valve V9439 is closed. A standard needle valve NV4 (Fig. 4) slowly bleeds air pressure from the syringe drain valve V5 17, the check valve CV4442, the accessory ports U2443 and U5 444, and an indicator IND-2 446.

When the PM actuator valve V8 420 is operated, air pressure is provided, through a check valve CV5 448, to and through the check valve CV1 432 and the check valve CV2 433 to pressurize the expansion chambers C1 434 and C2435, respectively. An expansion chamber C3449 is also pressurized through a check valve CV6450. It will be noted that, at this relative point in time, the condition of the first preferred embodiment 11 of the invention is like that previously described as existing immediately after the operation of the AM actuator valve V1 419 except that, in addition to the expansion chamber C1 434 and the expansion cham ber C2435 being pressurized, the expansion chamber C3449 is also pressurized. Actions previously discussed herein in relation to the bleeding off of pressure from the expansion chamber C1 434 and the expansion chamber C2435 also proceed, except that, when the expansion chamber C2 435 "bleeds off" (i.e. when the pressure is sufficiently reduced therein), the routing valve V9439 opens. This allows the pressure in the expansion chamber C3449 to open the purge air valve V10424 and the signal valve V15423, and to close the water valve V11 429 and a PM lockout valve V16451 , and to "turn on" (apply pressure to) a pneumatic indicator IND-3452 and a pneumatic indicator IND-4453. Pressure from the expansion chamber C3449 also opens the signal valve V14422, thereby supplying air pressure through the union U3440 to open the syringe drain valve V5 17 (Fig.4). The pressure in the expansion chamber C3 449 also is applied through the check valve CV4 442 to open the water coolant vaive (not shown) in the dental unit 2 (Fig. 1), thereby allowing air to purge the water system portion of the dental unit 2.

A precision needle valve NV3454 bleeds off air pressure in the expansion chamber C3449. When air pressure in the expansion chamber C3449 is depleted, the air vaive V10424 closes, the signal valve V14 422 closes, the standard needle valve NV4 447 finishes bleeding air pressure from the internal air tubes 567, the syringe vaive V5 17 closes, a quick exhaust QE1 455 opens and the water coolant valve (not shown) in the dental unit 2 (Fig. 1) closes. The water valve V11 429 and the PM lockout valve V16451 will remain closed, and the indicator I ND-4 452 will remain operated (on) until the AM actuator valve V1 419 is manually operated. The operation of valve V1 419, as previously discussed herein, begins a process of flushing the dental unit 2 with a disinfectant solution 456 from the solution reservoir 427 and then flushing and refilling the appropriate system hoses with water.

In addition to the components discussed above, Fig.4 reveals that a plurality of "tees" 457 (28 in the example of Fig. 4) and a plurality of four-way fittings 458 (4 in the example of Fig. 4) are used to accomplish the routings previously discussed herein.

It should further be noted regarding Fig. 4 that, in the actual physical manifestation of the first preferred embodiment 11 of the invention, components are closely stacked and placed one upon another so as to make the unit as compact as is practical. Therefore, in order to clearly show the operation of the invention, components shown in the view of Fig.4 are not necessarily located as they are in the physical manifestation of the invention. Indeed, as previously noted, the lockout valve V13417, the syringe drain valve V5 17 and the quick exhaust 455 are external to the AMB Flush System 11 (Fig. 1) proper. In the first preferred embodiment 11 of the present invention, the valves (using as an example, the purge air valve V10424) are pneumatically operated and have an actuator portion 459 and a body 460, which body 460 is either normally open ("NO") or normally closed ("NC") as indicated in Fig. 4. Also, in the first preferred embodiment 11 of the invention, the valves (e.g. 424), as well as most of the other components are made of brass. However, these factors are a matter of choice, depending upon cost considerations, and the like, rather than specifically on functionality. One skilled in the art will recognize that valves may be made of any of a number of materials, and that there are a variety of general valve constructions on the market, any combination of which can be used with success in accomplishing the present invention, provided that necessary considerations such as relate to hygiene and durability are met.

A plurality (three in the example of Fig.4) of output fittings (U8 through U10) 461 provide the output from AMB Flush System 11 to the dental unit 2 (Fig. 1) as well as or in addition to any other equipment (not shown) which might be connected to it for disinfection and cleaning.

Fig. 5 is a first equally prefened alternate embodiment 511 of the AMB Flush System of this invention. The first equally preferred alternate embodiment 511 of the invention is, in many respects, similar to the first preferred embodiment 11 previously described herein. References in Fig. 5 to "PV" are abbreviations for " Pinch Valve. "

Referring to Fig.5, in the first equally preferred alternate embodiment 511 of the present invention, the lockout valve PV13517, the indicator IND-1 418, the signal valve PV4521, the signal valve PV14522, the solution reservoir 427, the water valve PV11 529, the water input U11 430, the expansion chamber C1 434, the expansion chamber C2435, the syringe drain valve PV5540, the routing valve PV9539, the pinch valve PV4542, the accessory port U5444, the expansion chamber C3449, the indicator IND-3452, the indicator IND-4453, the disinfectant solution 456, and the output fittings 461 (Figs. 4 and 5) are alike in logical placement and function to those same referenced components as found in the first preferred embodiment 11. In the first equally preferred alternate embodiment 511 of Fig. 5, some components and or valves are optionally constructed of different materials or manner as is discussed below. A first dual valve V6/V7527 performs the functions formerly described in relation to both the water valve V7428 and the solution valve V6437 of the first preferred embodiment 11. Construction of the dual pinch valve

527 (as well as other such valves to be introduced hereinafter) will be discussed in more detail in relation to Fig.7.

A plurality (three in the example of Fig.5) of pinch type "timer delay" bleed off valves 545, 547 and 554 serve the same purpose in the first equally preferred alternate embodiment 511 of the invention (that being the timed slow "bleed off" of the expansion chambers 434, 435 and 449 respectively) as do the precision needle valves 445, 447 and 454 in the first preferred embodiment 11. The bleed off pinch valves 545, 547 and 554 function merely by pinching off a hose by a controlled amount. It is known in the art and practiced in the first preferred alternate embodiment 511 of this invention to run a string (not shown) through a hose where it is to be pinched off in this manner, so as to prevent the hose from closing entirely. The bleed off pinch valves 545, 547 and 554 and the needle valves 445, 447 and 454 are functionally interchangeable. Pinch valve 566 bleeds pressure away from vaive 542 and syringe drain valve 540.

In the first equally preferred alternate embodiment 511 of the invention, compressed air is introduced through an air input U1 412, passed via an internal air tube 413 to an air regulator R2514 and therefrom to a master toggle vaive PV2/PV3515 and to an increased flow pinch valve M 516. Although increased flow valve M 516 appears redundant, it has been found that the particular type of valves used in the first preferred alternate embodiment 511 of the invention require, for their best operation, an air flow somewhat greater than is delivered through the master toggle valve V2/V3 515. Furthermore, it is desirable to optimize the air flow for individual aspects of the application by providing increased air flow by means of the increased flow pinch valve M 516, as shown in Fig.5. Therefore, the master toggle vaive PV2 V3515 is used as a master controller with the increased flow pinch vaive M 516 actually delivering controlling air flow, with an increased size of internal air tube(s) 513 as may be appropriate to the particular valve and components used in the application.

When the master toggle valve PV2/V3515 is operated, air pressure is supplied from the increased flow pinch valve M 516 to the indicator IND-1 418, to a solution pressure regulator R1 525 and, through a check valve CV3526 to the solution reservoir 427, to a purge air valve PV10524, to a signal valve PV15 523, and to a combination valve PV17 528. The combination valve PV17 528 is a simple pinch valve capable of opening and or cbsing a relatively large number of hoses simultaneously. The combination valve V17528 used in the first equally preferred alternate embodiment 511 of the invention is a device well known in the art available from Proma Dental Manufacturing of Carson, CA When a start switch PV1 543 is momentarily operated, the combination valve PV17528 is opened such that the first expansion chamber C1 434 and the second expansion chamber C2435 are pressurized , and operations relating thereto are begun as previously described in relation to the first preferred embodiment 11 of the invention.

AM/PM selector pinch valve 530 is toggled such that it is in PM position 531 (that is, such that a PM air line 532 is open there through). Then momentary operation of the start switch PV1 543 causes the combination vaive PV17 528 to be opened such that the first expansion chamber C1 434, the second expansion chamber C2435 and the third expansion chamber C3449 become pressurized, and operations

relating thereto are initiated as previously described above. Pneumatic lock out valve PV 18551 prevents actuation of combination valve 528 a second time when 530 is in the PM position, and C3449 begins to bleed off. Both lock out valves 451 and 551 are actuated by bleed-off of chamber C3449.

As in the first preferred embodiment 11 of the invention, a plurality of tees 457 and four way fittings 458 are employed in this embodiment 511 , as shown in Fig.5. The expansion chambers C1 434, C2435, and C3449 are preferably made of plastic, but may also be made of metal such as stainless steel, brass or aluminum.

Valves preferably employed embodiment 511 are taught in Betush U.S. Patents Nos.5,026,020 and 5,097,868 of Proma Dental, the disclosures of which are incorporated by reference herein to the extent required for full and complete disclosure. It will be noted that these referenced patents disclose normally closed valves. However, these valves may be modified to be normally open valves. Fig. 6 is a cross sectional plan view of a typical pinch vaive 610 such as is disclosed in the Betush '020 Patent referenced above. Pinch vaive 610 has an actuator tube 612, an object tube 614 which is to be opened and closed (pinched off) as required, a housing 616, and a pinch mechanism 618 for acting upon the object tube 614 when the actuator tube 612 is inflated as described in the Betush '020 Patent. Fig.6 shows an uninf lated actuator tube 612 and tube 614 is closed (pinched off). When tube 612 is inflated, tube 614 opens. More than one object hose 614 may be acted on in a single pinch valve 610 by placing two or more object hoses 614, 614A side by side therein (one on top of the other as seen in Fig. 6). Thus, a second object hose is routed, as shown in Fig. 6, through an exit hole 620, such that the second object hose 614A is open when the actuator tube 612 is not inflated, and 614a is closed when the actuator tube 612 is inflated. As can be understood in tight of the above discussion, the pinch valve 610 may, by varying the routing of the object tubes 614 and 614A be made to be a dual normally closed valve, a dual normally open valve, or, as in Fig. 6, a combination normally open normally closed valve. Note for example alternate entry 621 for hose 614, Thus, the various valves discussed above in relation to the alternate embodiment 511 of the present invention are of the NC, NO or combination of pinch valve type described.

Fig. 7 is a second, equally preferred, alternate embodiment 711 of the AMB Flush System of the invention. This embodiment 711 differs from the first and alternate embodiments 11 and 511 in that the timing and sequence control is accomplished by electronic means rather then by pneumatic means in embodiment 711. Solenoid valves (designated "SV") in the following description correspond generally by number to valves (designated "V" or "PV") in the previous descriptions and functions thereof are easily understood by comparison thereto.

In the embodiment 711, compressed air is introduced through an air input U1 712 and provided, via an intemal air tube 713 to a solenoid valve SV8 714. When the solenoid valve SV8 714 is operated, air is provided to an air regulator REG 1 715, and then to an air regulator REG 2 716, through a check valve CV1 717 and thence to a solution reservoir 427.

When electrical power is applied to embodiment 711 via a system power switch P, 718, a light emitting diode ("LED") L1 719 will illuminate. The master solenoid valve SV8714 will operate (open) and

a foot control lockout solenoid SV12 720 will operate (close), thereby preventing the use of the dental handpieces 4 (Fig. 1). When the master solenoid valve SV8714 is operated, air is also supplied through the regulator R1 715 to an air signal solenoid SV9721 and to an air purge solenoid SV10722.

When AM switch 723 is operated, an LED L2735 lights, syringe drain solenoid SV5724 opens, and the solenoid SV9721 opens, thereby opening a water coolant supply valve 725, which is physically located in and a part of the dental unit 2 (Fig. 1), by means of an air signal supplied through a check vaive CV4 726. Air provided through the check valve CV4 is further supplied to an accessory air switch, which is merely a switched air resource optionally provided for controlling any accessory devices which require such control. Water is provided to the dental unit 2 (Fig. 1) through a water solenoid SV11 728. When the AM switch 723 is operated, the solenoid SV7 closes, thereby shutting off the normal supply of water to the dental unit 2 (Fig. 1), and a solution solenoid SV6729 opens releasing the disinfectant solution 456 through a unit water output 730 into and through the interconnection hose 8 (Fig. 1). After a first preset time period (timing will be discussed in more detail below), the solution solenoid SV6729 closes and the water solenoid SV7728A opens, thereby flushing the interconnection hose 8 and the dental unit 2 (Fig. 1) with water.

After a second predetermined time, the air signal solenoid SV9721 and the syringe drain solenoid SV5 724 close and the LED L2 735 is tumed off. When the user turns off the master switch P 718, the dental unit 2 (Fig. 1) will be ready for use.

Pressing a PM switch 731 initially causes all of the operations discussed above in relation to the operation of the AM switch 723. in addition, after the water solenoid valve SV7 728A has flushed the dental unit 2 (Fig. 1) with water for the second predetermined time, the water solenoid SV11 728 again closes off the water supply, an LED L3732 and LED L4734 illuminates, and the solenoid SV10722 opens thereby purging the dental unit 2 (Fig. 1) and the interconnection hose 8 with air for a third predetermined time. Thereafter, the solenoid SV10722 closes (shutting off purge air) and the LED L3732 is tumed off. The water solenoid SV11 728 is a magnetically latching solenoid which will remain closed (thereby preventing the entry of water into the dental unit 2 (Fig. 1), and the LED L4734 will remain on until the AM switch 723 is depressed, thereby flushing the dental unit as previously discussed above. it will be noted that operation of the dental unit 2 cannot immediately follow the series of operations following the operation of the PM switch 731 (step 318 in Fig. 3). Refer again to the above discussion of Fig. 3. Rather, operation of the AM switch 723 (step 313 in Fig.3, and the following automated functions, as discussed above in Fig. 3) must follow the operation of the PM switch 731. The AM switch 723 may, however, be operated whenever required without an intervening operation of the PM switch 731. In embodiment 711, stainless steel is used extensively in the component structure, although, as discussed above with embodiments 11 and 511 , other materials, such as plastic, can be employed for many of the components.

Fig.7 shows an embodiment in which value unit 709 is physically distinct from an electronics unit 710. This is analogous to the optional separation of the system control 9 from the indicator unit 10

discussed above in relation to Fig. 1. A power transformer 704 provides 24V AC power to the electronics unit 710. When power switch P, 718 is activated by the user, the air lockout solenoid SV12 720 is actuated to lock out operation of the handpieces 4 by the foot control 5 (Fig. 1).

Fig.8 is an electrical schematic of the embodiment 711. In Fig. 8, embodiment 711 includes in the circuit combination shown: a dual timer 835 (type 556); a single timer 836 (type 555); a bilateral switch 837 (type LM4066); four field effect transistors ("FET's") 838 (type IRF510 MOSFET), designated 838a through 838d; nine diodes 839A-J (type 1 N4001); a bridge rectifier 840; a plurality (types and quantities discussed below of resistors 841 A- J; and a plurality (types and quantities discussed below) of capacitors 842A-I. Power is provided from the power transformer 734 (Fig. 7) through a power jack 843 and is switched to the bridge rectifier 840 by the power switch P 718. When contact is made through the power switch P 718, direct current voltage is filtered by first and second capacitors 842a and 842b in parallel, and provided to a voltage regulator 844. The output of the voltage regulator 844 is controlled by a first fixed resistor 841a and a first variable resistor 841b. When there is output from the voltage regulator 844, the LED L1 719 is lit and the solenoid SV12720 is operated to "lock out" operation of the dental unit 2 (Fig. 1). A second fixed resistor 841 c limits current through the LED L1 719. When the AM Switch 723 is operated, the dual timer 835 and single timer 836 are each reset to zero. Then the latching bilateral switch 837 is opened so only the dual timer 835 is triggered to start counting. When the PM switch 731 is operated the same applies as in the AM procedure, except the single timer 836 also starts counting. These differential counting functions result from the circuit logic arising from the location of a first diode 839a with respect to the AM switch 723 and a second diode 839b with respect to the PM switch 731. A first time period is set by a fourth capacitor 842d, a fifth capacitor 842e, and a second variable resistor 841 d. A second time period is set by a sixth capacitor 842f , a seventh capacitor 842g, and a third variable resistor 841 e. A third time period id set by an eighth capacitor 842h, a ninth capacitor 842i, and a fourth variable resistor 841 f. The above reset and timing operations are in accordance with the normal usage, and the published instructions for use, of the dual timer 835 and the single timer 836.

During the first time period, the first FET 838a is biased into conduction such that the solution solenoid SV6 729 and the water solenoid SV7 728 are operated. The LED L2 735 is lit, with current through it being limited by a fourth fixed resistor 841 g. A third diode 839c and a fourth diode 839d are provided as shown in Fig.8 to prevent reverse current surges during operation of the solenoids 729 and 728 respectively.

During the second time period, the second FET 838b is biased into conduction such that the syringe drain solenoid SV5724 and the air signal solenoid SV9721 are operated. The LED L3732 is lit, with current through it being limited by a fifth fixed resistor 841 h. A fifth diode 839e and a sixth diode 839f are provided as shown in Fig. 8 to prevent reverse current surges during operation of the solenoids 724 and 721.

During the third time period, the third FET 838c is biased into conduction such that the air purge solenoid SV10 722 and the water lockout solenoid SV11 728 are operated. The LED L4 734 is lit, with

current through it being limited by a sixth fixed resistor 841 i. A seventh diode 839g and an eighth diode 839h are provided as shown in Fig.8 to prevent reverse current surges during operation of the solenoids 728 and 722.

When the third FET 838c is initially biased into conduction by the single timer 836, the fourth FET 838d is also biased into conduction and the bilateral switch 837 is triggered to on through a ninth diode 839j. Therefore, even after the third time has expired and the third FET 838c has stopped conducting, the solenoids SV10722 and SV11 728 will remain operated and the LED L4733 will remain lit until the AM switch P 723 is engaged by the operator. A seventh fixed resistor 841 j biases the bilateral switch 837. An emergency reset switch E 845 resets the dual timer 835 and the single timer 836. If the E Switch 845 is pressed, the AM procedure will then have to be initiated before the dental unit will reactivate. The resistors 841 are of the values shown in the schematic of Fig. 8 and listed here: 841a 240 Q 841 d 10 KΩ variable 841 g 620 Q 841 i 620 Ω

841b 5 KΩ variable 841 e 10 KΩ variable 841 h 620 Ω 841 j 2MΩ

841c 620 Ω 841f 10 KΩ variable The capacitors 842 are of the values shown in the schematic of Fig. 8 and listed here:

842a 220 μf 842d 100 μf 842g 100 μf

842b 100 μf 842e .01 μf 842h .01 μf

842c 1.0 μf 842f .01 μf 842i 100 μf

An automatic timer 846 is provided as a preferred option. A multiplug 847, or in the case of pneumatic operation a 3-position disconnect, attaches to the (AMB) control 711, providing operator presettable times for activation of the AM and PM Modes 323 and 324. By pushing timer clock set 898, and either the AM set button 849 or the PM set button 850, the clock 851 can be advanced by hitting "+" button 852 or retarded by hitting "-" button 853. The appropriate LED 854 for AM or PM lights to show which mode the controller is in. A battery backup 855 is included. Multiple cycles can be set for a given period, e.g. per day, per week or indefinitely. Factory preset default modes, e.g. a minimum number of cycles at a preset time, say 10 PM and 7 AM may be included in a clock memory. This timer may also include a volume flow control meter as an alternative or additional control feature. A battery backup 855 is provided in case of a power failure, so the preset times are kept intact. There are two versions of the timer electronic and pneumatic. A system battery backup 856, typically a gel-cell battery kept at full charge via a trickle charger, is a preferred option to power the entire AMB Flush System operation in case of power failure.

Fig.9 is an exploded isometric view of a reservoir bottle 910 such as is optionally used with the AMB Flush System 10 of the invention. A reservoir cap 911 screws onto the reservoir bottle 910 by the union of a cap threading 912 and a bottle threading 913 in the manner of conventional "screw on" type bottle caps (not shown). A plurality (four in the example of Fig. 9) of hose receptor recesses 914 are adapted for receiving (one each per hose) an end of the handpiece hoses 6a after the handpiece 4 (Fig. 1) has previously been removed therefrom, such that fluids may pass through the handpiece hose 6a into

the reservoir bottle 910. An annular stop lip 915 at the bottom of each of the hose receptor recesses 914 stops the handpiece hose 4 from passing into the reservoir bottle 910.

As can be appreciated in light of the above discussion, all three embodiments 11, 511 and 711 of the invention have two cycles: A PM series 324 and an AM series 323 (Fig. 3). The AM series may be performed at any time that the dental unit 2 (Fig. 1) is not in operation, and the dental unit 2 may be used immediately thereafter. The PM series 324 leaves the hoses 6 and 8 "air dried" to prevent microbial growth when the dental unit 2 is not to be used for an extended period of time, such as in the evening, overnight, vacations, weekends, off days (closed hours) or long waiting periods between procedures. In this regard it has been discovered that air drying the hoses 6 and 8 is a very important in preventing the growth of biofilm and/or microbes in the dental unit 2 and related hoses 6 and 8. Further, in accord and with the best presently known embodiment of the inventive method 310, the dental unit 2 cannot be used immediately following the PM series 324. Rather, the AM series 323 must be run following the PM series 323 to insure a reflushing after the longer period of non-use. The dental unit 2 is further made inoperative during either the AM series 323 or the PM series 324 of operational steps. The overall programmable system timer 856 (Fig. 8) can be employed to initiate the PM cycle, say at the end of each working day, so the operation of the AMB Flush System is completely automatic. Likewise, a conventional "low reservoir" fluid level sensor system 740 (Fig. 7) may be placed into the reservoir 427 to initiate a "low" or "full reservoir" LED and/or pizeoannunciator 742 on the control console 2, 10, 511 , or 711 as desired. This can be connected via a MOSFET switch to interrupt the AMB power so the unit will not operate with inadequate disinfectant supply.

In any of the present embodiments 11, 511 and 711 of the invention, the indicators IND-1 418 and or the LED L1 719 indicate that the respective embodiment is "on." The indicators IND-2446 and/or LED L2735 indicate that the AM series 323 (Fig. 1) is being performed. The indicators IND-3452 and/or the LED L-3732 indicate that the PM series 324 is being performed. The indicators IND-4453 and/or the LED-4 734 indicate that the dental unit 2 water supply is locked out."

Although all of the time periods involved in the inventive method 310 are variable as discussed in relation to the various present embodiments 11, 511 and 711, it is currently believed that 3 minute periods are generally adequate for each of the "flush system with solution" steps 314 and 319 and the "flush system with water" steps 315 and 320. While no optimal time for the flush system with air step 321 has yet been determined, it is thought that approximately 15 minutes should be sufficient, although a longer time period would be optimal.

Any of a number of disinfectant, antimicrobial, or sterilizing fluids may be used as the disinfectant solution 456, although it is currently accepted in the field that a 10% solution of commercially available Clorox® bleach is appropriate for such purposes. (Note that commercial grade Clorox® bleach contains 5.5% sodium hypochlorite solution, and so the appropriate concentration of sodium hypochlorite is approximately 0.05%.) Other solutions include alcohol, peroxide, ozone, betadyne and the like, aqueous disinfectant solutions, or a combination thereof.

Although there is substantial tolerance for variance, in the present embodiments 11 , 511 and 711 of the invention, supply air pressures are approximately 70 pounds per square inch ("psi"), with regulated air pressure therein being reduced to approximately 50 psi. Air pressure supplied to the solution reservoir

456 further reduced to approximately 35 psi, since the plastic solution reservoir 456 cannot withstand the much greater pressures.

INDUSTRIAL APPLICABILITY:

It is evident that the system apparatus and methods of the invention have wide industrial, commercial and clinical applicability to water line treatment. Although the present invention has been described herein as being useful primarily with dental equipment, it is equally useful for use with general medical equipment or in any application wherein it is desirable or necessary to keep fluid delivery lines free of microbial growth during periods of low or non-use including water fountains, refutable bottle water dispensing stations, plumbed coffee and soft drink makers and the like. The AMB Flush Systems 11 , 511 , 711 of the present invention may be utilized in essentially any application wherein conventional dental units

2 are used. Since the AMB Flush System 11 , 511 , 711 of the present invention may be readily constructed are readily compatible with existing hardware, as a retrofit or integrated into a new dental unit design, it provides an important new means and method for preventing dangerous microbial growth, particularly in dental and medical equipment. It is evident that the utility and medical applicability of the invention will be both significant in scope and long-lasting in duration.

It should be understood that various modifications within the scope of this invention can be made by one of ordinary skill in the art without departing from the spirit thereof. I therefore wish my invention to be defined by the scope of the appended claims as broadly as the prior art will permit, and in view of the specification if need be.