Sterile fluid delivery system and method

A sterile fluid delivery system that incorporates a specialized handpiece adapter placed between a standard dental or other medical handpiece and a conventional tube set. The tap water conduit in the conventional tube set is blocked by the handpiece adapter and instead a tube set connected to the adapter provides a supply of sterile fluid for delivery to a work site. A peristaltic pump delivers fluid from a sterile supply to the handpiece adapter. Motor exhaust air pressure from the adapter is applied to the pump to activate a pressure-sensitive switch. The pump automatically turns on when the medical tool is activated and turns off when the tool is deactivated.

FIELD OF THE INVENTION 
This invention is in the field of delivering sterile water or other fluid 
to medical air-powered instruments, more commonly dental handpieces. 
BACKGROUND OF THE INVENTION 
Many of the powered tools employed by modern dentists and oral surgeons 
operate by means of an air-driven motor. In operation, a stream of 
high-pressure air from an inlet conduit rotates the motor and exits 
through an exhaust conduit. The rotating motor in turn rotates a rotatably 
connected tool, such as a drill. 
Because of the heat generated by the friction between the rotating tool and 
the patient's hard tissue (e.g., bone or teeth), it is necessary to supply 
a stream of coolant water to the work site. In addition to performing a 
cooling function, the water is also useful for irrigating the work site, 
removing the debris created during the tool's operation. 
The tool is mounted on one end of a standard dental or surgical handpiece, 
which in turn connects to a conventional tube set, which is usually part 
of a conventional dental or surgical unit. This tube set provides conduits 
for inlet air to drive the motor and exhaust air from the motor. The 
conventional tube set also contains a conduit for the cooling and 
irrigating water, and may further contain a conduit for the chip air. A 
separate conduit for a fiber optic cable may also be contained in the 
conventional tube set. 
Conventional dental units have traditionally used water from a community 
source, often called "tap water". Tap water contamination and water line 
contamination within the dental unit have led to concerns over patient 
safety. This has led to the development of a number of systems that use 
water from a sterile water source. One such system is disclosed in U.S. 
Pat. No. 4,470,812 to Martens, et al., in which a disposable dual chamber 
cartridge of sterile water is interposed in the normal tap water delivery 
line. Pressure from the tap water flows into a first cartridge chamber and 
forces sterile water from a second adjacent cartridge chamber into the 
dental handpiece for delivery to the work site. One drawback of this 
system is the potential for the tap water to contaminate the sterile water 
in the event the seal separating the two chambers loses its integrity. 
Furthermore, continuously filling the cartridge with tap water during 
operation of the dental tool requires vigilance to ensure that the 
cartridge does not overfill and potentially burst. While the use of a 
short sterile water supply tube permits the cartridge to be located near 
the dental handpiece, this arrangement is inconvenient for the operator 
and may also interfere with the operation of the handpiece. Moreover, 
disposal of the sterile water cartridge after only a single use can be 
somewhat costly. 
Another system is disclosed in U.S. Pat. No. 5,360,338 to Waggoner, in 
which a dental handpiece is connected to a control box containing internal 
air and sterile water supply networks. A drawback of this system is its 
complex arrangement of tubing, connectors, and valves to provide sterile 
water during the operation of the dental tool. 
It is therefore highly desirable to provide a simple sterile fluid supply 
system that connects to both a standard dental handpiece and a 
conventional tube set and eliminates the risks of fluid contamination and 
system overfilling. 
SUMMARY OF THE INVENTION 
The present invention provides a sterile fluid delivery system that 
incorporates a specialized handpiece adapter placed between a standard 
medical handpiece and a conventional tube set. An adapter tube set is 
connected to the handpiece adapter and provides a supply of sterile fluid 
to the handpiece for delivery to the work site. As with the medical 
handpiece and medical tools, the handpiece adapter and its associated tube 
set can be removed and sterilized. This sterilization prevents any 
contaminated fluid from remaining in the handpiece, the adapter, or the 
adapter tube set after it has been used for treating any given patient. 
In the preferred embodiment of the invention, a peristaltic pump delivers 
water from a sterile water supply to the handpiece adapter. Air pressure 
which is provided to operate a motor or other tool connected to the 
handpiece is utilized to initiate operation of the pump. Preferably, motor 
exhaust air from the adapter is delivered to the pump to activate a 
pressure-sensitive switch. In the preferred mode of operation, then, the 
pump automatically turns on when the dental tool is activated and turns 
off when the tool is deactivated. The operator of the dental tool thus 
need not be concerned about any controls to initiate the delivery of the 
sterile water. Further, in this embodiment, the tap water conduit in the 
conventional tube set is blocked by the handpiece adapter. Consequently, 
the tap water supply should be turned off altogether. 
In a second embodiment of the invention, tap water is delivered from the 
handpiece adapter to a small, disposable external water filter. The tap 
water passes through the filter and is, in turn, delivered back to the 
handpiece adapter. In this embodiment, there is no possibility that the 
tap water can contaminate the filtered water. In addition, the light 
weight filter can be easily carried adjacent to the adapter, and frequent 
replacement of the filter is easy and practical.

DETAILED DESCRIPTION 
Referring now to the drawings, FIG. 1 shows an overview of the preferred 
embodiment of the sterile water delivery system 1. The system 1 includes a 
handpiece adapter 2, which is interposed between a standard handpiece 3 
and a conventional tube set 4. The handpiece 3 has a tool 5 located at its 
forward end and connecting threads 6 at its rearward end. The conventional 
tube set 4 has a connector 7 at its forward end and is connected to one or 
more air supplies and a community water supply at its rearward end (not 
illustrated). In a conventional system, the connector 7 of the 
conventional tube set 4 is connected to the standard handpiece 3 via its 
connecting threads 6. 
The handpiece adapter 2 has a generally cylindrically shaped body with a 
connector 8 at its forward end that is substantially identical to the 
connector 7 of the conventional tube set 4. The handpiece adapter 2 also 
has connecting threads 9 at its rearward end that are substantially 
identical to the connecting threads 6 of the handpiece 3. As a result, the 
handpiece adapter 2 can be connected directly in line between the 
conventional tube set 4 and the standard handpiece 3. 
Referring to FIGS. 2A and 2B as well as FIG. 1, the sterile water delivery 
system 1 also includes a pump unit 10 and a sterile water supply 11. A 
supply tube 12 connects the sterile water supply 11 to the pump unit 10 
and an adapter tube set 13 connects the pump unit 10 to the handpiece 
adapter 2. The sterile water supply 11 is hung from a water supply hanger 
14, which is mounted at the rear of the pump unit 10 via hanger mounting 
bracket 15. The sterile water supply may also be provided by a bottle of 
sterile water (not illustrated). The supply tube 12 has a spike 16 at its 
rearward end that punctures the sterile water supply 11, allowing sterile 
water 17 to flow from the sterile water supply 11 to the pump unit 10. 
The pump unit 10 preferably includes a peristaltic pump 18 and has a pump 
housing 19 on its upper surface. Peristaltic pumps are well known in the 
art, such as Micro Motors, Inc.'s Micro SWP Sterile Water Pump or Omega 
Engineering, Inc.'s "OMEGAFLEX".RTM. Peristaltic Pump. One advantage of 
using a peristaltic pump is that the pumping chamber consists of a fluid 
tube or "pump tube" 20. The sterile water 17 is confined within the pump 
tube 20 and is thus not contaminated by the peristaltic pump 18. Other 
advantages include positive displacement of the sterile water 17, no back 
flow of the sterile water 17, self-priming of the pump 18, siphoning of 
the sterile water 17 is not necessary, and the peristaltic pump 18 can run 
with no sterile water 17 in the pump tube 20 without damage. 
The pump tube 20 runs through the pump housing 19 on the pump unit 10. The 
rearward end of the pump tube 20 connects to the forward end of the supply 
tube 12, thereby allowing the pump tube 12 to receive sterile water 17 
from sterile water supply 11. In addition, a power cord 21 is attached to 
the rear of pump unit 10 and plugs into an electrical outlet (not 
illustrated) to provide power to the pump unit 10. 
The adapter tube set 13, preferably mounted alongside the conventional tube 
set 4 via twist type clips 22, comprises both an irrigation tube 23 and a 
control signal tube 24. The rearward end of the irrigation tube 23 is 
connected to the forward end of the pump tube 20, and the forward end of 
the irrigation tube 23 is connected to the handpiece adapter 2. This 
arrangement allows sterile water 17 to be delivered to the handpiece 
adapter 2 from the pump tube 20 via the irrigation tube 23. 
In addition, the rearward end of the control signal tube 24 is connected to 
the pump unit 10, and the forward end of the control signal tube 24 is 
connected to the handpiece adapter 2. In the preferred mode of operation, 
when the tool 5 on the standard handpiece 3 is in operation, the control 
signal tube 24 provides the pump unit 10 with a signal to turn the pump 
unit 10 on. 
FIG. 2A shows a first detailed view of the pump unit 10. In this view, a 
pump housing cover 25 is in its closed position and each of the tube 
connections has been made. More particularly, pump tube 20 enters an input 
side 26 of the peristaltic pump 18 and exits an output side 27 of the 
peristaltic pump 18. The pump tube 20 connects to the supply tube 12 at a 
first fluid connection 28 and to the irrigation tube 23 at a second fluid 
connection 29. 
The pump unit 10 also includes a power switch 30, a switch selector 31, a 
flow rate adjuster 32, and a control signal fitting 33. The switch 
selector 31 allows the operator to choose among two modes of operation of 
the pump unit 10, automatic mode (operates when the handpiece is on) or 
manual mode. The flow rate adjuster 32 allows the operator to adjust the 
rate of flow of the sterile water 17 through the pump tube 20. Finally, at 
a control signal connection 34, the control signal fitting 33 is connected 
to the control signal tube 24 on its upper side and a short 
pressure-sensitive switch tube 35 on its lower side. The 
pressure-sensitive switch tube 35 is, in turn, connected to a 
pressure-sensitive switch 36 located inside the pump unit 10. The 
preferred pressure-sensitive switch 36 is manufactured by Press-Air-Trol 
of New York. The pressure-sensitive switch 36 responds to a control signal 
from the control signal tube 24, turning the pump unit 10 "on" when the 
tool 5 has been activated and "off" when the tool 5 has been deactivated. 
FIG. 2B shows a second detailed view of the pump unit 10. In this view, the 
pump housing cover 25 is in its open position and each of the tube 
connections have been undone. More particularly, the peristaltic pump 18 
contains three pump rollers 37. The pump tube 20 passes between the pump 
rollers 37 and the pump housing 19. 
The first fluid connection 28 comprises a male luer 38 on the forward end 
of the supply tube 12 and a female luer 39 on the rearward end of the pump 
tube 20. The male luer 38 is inserted in its counterpart female luer 39 to 
permit sterile water 17 to pass from the supply tube 12 into the pump tube 
20. 
Similarly, the second fluid connection 29 comprises a male luer 40 on the 
forward end of the pump tube 20 and a female luer 41 on the rearward end 
of the irrigation tube 23. Again, the male luer 40 is inserted in its 
counterpart female luer 41 to permit sterile water 17 to pass from the 
pump tube 20 into the irrigation tube 23. 
Finally, the control signal connection 34 comprises the control signal 
fitting 33 on the pump unit 10 and a tube fitting 42 on the rearward end 
of the control signal tube 24. The tube fitting 42 is inserted onto the 
control signal fitting 33 to permit the control signal to pass from the 
control signal tube 24, through the control signal fitting 33 and 
pressure-activated switch tube 35, and to the pressure-activated switch 36 
inside the pump unit 10. 
FIGS. 3A-3D show detailed views of the preferred embodiment of the 
handpiece adapter 2. The handpiece adapter 2 comprises an adapter body 43 
with a connector 8 on its forward end and connecting threads 9 on its 
rearward end. Four separate conduits pass longitudinally through the 
entire length of the handpiece adapter 2: (1) an inlet air conduit 4; (2) 
an exhaust air conduit 45; (3) a chip air conduit 46; and (4) a fiber 
optic conduit 47. In addition, a water conduit 48 passes longitudinally 
through the forward portion of the handpiece adapter 2. 
An inlet air tube 49 extends from the rear of the handpiece adapter 2 and 
connects to the inlet air conduit 44 and a corresponding conduit (not 
illustrated) in the conventional tube set 4. Similarly, an exhaust air 
tube 50 extends from the rear of the handpiece adapter 2 and connects to 
the exhaust air conduit 45 and a corresponding conduit (not illustrated) 
in the conventional tube set 4. Further, a chip air tube 51 extends from 
the rear of the handpiece adapter 2 and connects to the chip air conduit 
46 and a corresponding conduit (not illustrated) in the conventional tube 
set 4. Finally, the fiber optic conduit 47 aligns with a corresponding 
conduit (not illustrated) in the conventional tube set 4. 
As illustrated in FIG. 3A, an important aspect of the preferred embodiment 
of the invention is that the water conduit 48 does not pass through the 
entire length of the handpiece adapter 2. Instead, the water conduit 48 
passes through the forward portion of the handpiece adapter 2 and through 
the outer side surface of the adapter body 43, where a water tube-in 52 is 
rigidly inserted into the water conduit 48. The water tube-in 52 extends 
below the adapter body 43 and projects rearwardly, positioned such that it 
will not interfere with the connector 7 of the conventional tube set 4 and 
the connecting threads 9 of the handpiece adapter 2. 
The forward end of the irrigation tube 23 is connected to the water tube-in 
52 to supply sterile water 17 to the handpiece adapter 2. With this 
configuration, no tap water is supplied by the conventional tube set 4, 
and indeed the handpiece adapter 2 blocks off the tap water conduit in the 
conventional tube set 4. Thus, tap water cannot be inadvertently supplied 
to contaminate the sterile water 17. Consequently, when using the 
preferred embodiment of the invention, the tap water supplied to the 
conventional tube set 4 should be turned off at its source. 
A further important aspect of the preferred embodiment of the invention is 
illustrated in FIG. 3D. The high-pressure air from the inlet air conduit 
44 is typically delivered to the air-driven motor, subsequently passing 
through the exhaust air conduit 45 at a considerably lower pressure 
(depending on the outlet conditions). The exhaust air conduit 45 not only 
passes longitudinally through the entire length of the handpiece adapter 2 
but also branches off through the outer side surface of the adapter body 
43, where an exhaust air tube-out 53 is rigidly inserted into the exhaust 
air conduit 45. As with the water tube-in 52, the exhaust air tube-out 53 
extends below the adapter body 43 and projects rearwardly, positioned such 
that it will not interfere with the connector 7 of the conventional tube 
set 4 and the connecting threads 9 of the handpiece adapter 2. 
The forward end of the control signal tube 24 is connected to the exhaust 
air tube-out 53 to permit a portion of the exhaust air to be diverted from 
the exhaust air conduit 45 to the control signal tube 24. With this 
configuration, when the dental tool 5 is activated, the pressure of the 
exhaust air returning from the air-driven motor is applied through the 
control signal tube 24 to be sensed by the pressure-sensitive switch 36 in 
the pump unit 10. The pressure-sensitive switch 36, sensing the increased 
pressure in the control signal tube 24, turns on the peristaltic pump 18, 
thereby commencing delivery of the sterile water 17 through the irrigation 
tube 23 to the handpiece adapter 2. Correspondingly, when the dental tool 
5 is deactivated, the peristaltic pump 18 is automatically turned off by 
the pressure sensitive switch 36, thereby ceasing delivery of the sterile 
water 17 to the handpiece adapter 2. The pressure-sensitive switch 36 
preferably responds to an air pressure of approximately 0.5 pounds per 
square inch. 
Although utilizing exhaust air pressure to activate the pump is preferred, 
because the fluid flow stops as soon as air flow to the air motor stops, 
it should be recognized that inlet air could be ducted to the pressure 
responsive switch. It has been found, however, that, the inlet pressure 
may keep the fluid delivery pump running for a few seconds after the air 
motor stops. Thus fluid continues to be provided to the tool site when 
none is needed. 
A primary advantage of the present invention is the ability to sterilize 
each of the components that may become contaminated during operation of 
the system 1. Not only can the dental tool 5 and the standard handpiece 3 
be sterilized, but the handpiece adapter 2, the adapter tube set 13, and 
the pump tube 20 can also be sterilized after each use. Each of these 
components can, for example, be disassembled from each other and placed in 
an autoclave after the components have been used with a given patient. 
After any contamination has been eliminated, the components can be 
reassembled for use with the next patient. 
FIGS. 4A-4C show detailed views of a second embodiment of the handpiece 
adapter 2A. The handpiece adapter 2A comprises an adapter body 54 with a 
connector 8 on its forward end and connecting threads 9 on its rearward 
end. The handpiece adapter 2A of the second embodiment differs from the 
preferred embodiment in that it uses tap water supplied from the 
conventional tube set 4, passes that tap water through a suitable external 
water filter 55, and returns the filtered water to the handpiece adapter 
2A for delivery to the work site. The particular filter used does not form 
a part of the present invention. SciTech Dental, Inc. of Seattle, Wash. 
markets a filter identified as "CLEARLINE".TM. Microfiltration Cartridge, 
under U.S. Pat. Nos. 4,113,627 and 5,204,004. SciTech indicates such 
filter is suitable for use with the adapter 2A. As illustrated in FIGS. 
4A-4C, the second embodiment does not have an exhaust air tube-out. 
In this embodiment, a tap water tube 56 extends from the rear of the 
handpiece adapter 2A and connects to a tap water conduit 57 in the 
handpiece adapter 2A and a corresponding conduit (not illustrated) in the 
conventional tube set 4. The tap water conduit 57 passes through the 
rearward portion of the handpiece adapter 2A and through the outer side 
surface of the adapter body 54, where a tap water tube-out 58 is rigidly 
inserted into the tap water conduit 57. The tap water tube-out 58 extends 
below the adapter body 54 and projects rearwardly, positioned such that it 
will not interfere with the connector 7 of the conventional tube set 4 and 
the connecting threads 9 of the handpiece adapter 2A. 
Similar to the preferred embodiment, a filtered water conduit 59 passes 
through the forward portion of the handpiece adapter 2A and through the 
outer side surface of the adapter body 54, where a filtered water tube-in 
60 is rigidly inserted into the filtered water conduit 59. The filtered 
water tube-in 60 extends below the adapter body 54 and projects 
rearwardly, positioned such that it will not interfere with the connector 
7 of the conventional tube set 4 and the connecting threads 9 of the 
handpiece adapter 2A. 
In operation, tap water passes from the conventional tube set 4, through 
both the tap water conduit 57 in the handpiece adapter 2A and the tap 
water tube-out 58, and to the water filter 55. The water filter 55 removes 
any impurities or contamination from the tap water and delivers filtered 
water to the filtered water conduit 59 in the handpiece adapter 2A via the 
filtered water tube-in 60. 
While the invention has been primarily described as a sterile water 
delivery system, the apparatus may of course be used to deliver other 
fluids by themselves or with water. For example, it may be desirable to 
deliver medications or antiseptics with water. 
While the above detailed description has shown, described, and pointed out 
the fundamental novel features of the invention as applied to two 
embodiments, it will be understood that various omissions, substitutions, 
or changes in the form and details of the illustrated device may be made 
by those skilled in the art without departing from the spirit of the 
invention. Consequently, the scope of the invention should not be limited 
to the foregoing discussion but should be defined by the appended claims.