60/115,115, filed January 12,1999.

TECHNICAL FIELD This invention relates to breast pumps, and more particularly to overflow and flush systems of breast pumps.

BACKGROUND Breast pumps are convenient for nursing mothers, because, among other things, they allow the nursing mother to draw off breastmilk to feed to the child at a later time when the mother may not be present. For some mothers, breast pumps are required, particularly when the child has sucking difficulties or if the mother has problems with excessive or deficient milk production, or cannot empty completely. Some mothers also require breast pumps in the event of soreness or injury of the mammilla, or sunken mammilla.

One problem associated with breast pumps is the breastmilk or other fluids tend to overflow into the internal pump mechanisms. When this overflowed breastmilk is not cleaned from the pump mechanisms, the breastmilk may become

contaminated. Several studies have connected serious infant illnesses and even death to pathogens passed from contaminated breast pumps.

There are various methods that purport to prevent the overflow of breastmilk. Some of these methods describe a simple overflow bottle, while others use floating ball valves and/or other means to prevent the entry of breastmilk into the internal pump mechanisms. However, each of these methods has been ineffective in completely preventing breastmilk from entering the internal pump mechanisms.

To prevent contamination after breastmilk enters the pump mechanism, the pump must be thoroughly cleaned. Cleaning the pump involves a time consuming process of disassembly and cleaning of internal pump parts. Because this is a labor intensive job, it is often ignored and not performed. The pump may also fluid-flushed, but this requires skillful control of the water volume to prevent flooding the interior of the pump and the electrical pump components. Typically, fluid-flushing is only performed by authorized biomedical personnel.

What is needed is a system to stop the flow of breastmilk before the internal pump mechanisms become contaminated. If any breastmilk should enter the pump, an

automated flushing system is desired that can be operated at home without specialized training.

SUMMARY The present invention is a breast pump including an overflow sensor and automated flushing system. The overflow sensor, which may be an infrared sensor, detects the presence of breastmilk entering the internal pump mechanisms and instantly shuts off the pump to prevent contamination. The automated flushing system provides a series of specifically timed suck and release cycles at varying suction levels to systematically pull an appropriate amount of cleansing fluid through the pump mechanism to ensure proper cleaning and removal of all breastmilk residue.

One aspect of the invention is a breast pump comprising a pump enclosure and an overflow sensor. The overflow sensor detects the introduction of fluid into the pump enclosure and communicates to turn off the pump when the fluid is detected. The fluid may be breastmilk. The overflow sensor may be an infrared sensor.

Another aspect of the invention is a method for autoflushing a breast pump. The method comprises setting a suction level and applying a suction at the set level for a predetermined period of time. The autoflushing method the removes the suction for a predetermined period of time and

determines if an additional cycles are necessary. If additional cycles are necessary, the above steps are repeated.

Finally, the method comprises running the pump dry for a predetermined period of time. The autoflushing method may be activated by either a manual control or automatically. The autoflushing method may vary the suction level, the predetermined period of time to apply the suction, and the predetermined period of time to remove the suction.

DESCRIPTION OF DRAWINGS These and other features and advantages of the invention will become more apparent upon reading the following detailed description and upon reference to the accompanying drawings.

Figure 1 is an exemplary embodiment of a motor driven breast pump according to one embodiment of the present invention.

Figure 2 is a schematic diagram illustrating a side- view of the motor driven breast pump of Figure 1 showing the connection of the regulator to a vacuum source and a reservoir.

Figure 3 is a schematic of a regulator of the embodiment of Figure 1.

Figure 4 shows a schematic for an exemplary system comprising a breast pump with an auto-flush feature and overflow sensor according to the present invention.

Figure 5 shows a control panel for an exemplary system comprising a breast pump with an auto-flush feature and an sensor for overflow control; the control panel including an on/off switch, controls indicating suction levels; controls indication timing of suction; an autoflush control switch and an overflow indicator light.

Figure 6 is a flowchart illustrating the process of the autoflush system according to the present invention.

DETAILED DESCRIPTION Breast pumps for extracting or expressing breastmilk from a woman's breasts for later use by an infant have been available for years and are well known in the art. As the system of the invention can be adapted to be used for all mammals, breast pumps will vary, depending on which species the invention is practiced. Milk pumps for domesticated animals can be readily adapted for use on wild animals.

Breast pumps typically include a funnel-shaped"hood,"or "shield,"or flange suitable for coupling to a breast (one or, optionally, both breasts at the same time), that is placed over the nipple and a substantial portion of the breast. A reduced pressure or vacuum is intermittently generated in the

hood to cause milk to be expressed from the breast within the hood. The milk then flows from the hood to a storage container, or reservoir, for later use. Reservoirs can be removable.

Generally, two types of breast pumps have been marketed for use by nursing women: motor-driven pumps; and manually-operated pumps.

Manually-operated breast pumps, the intermittent suction action is typically generated by means of a compressible bulb or, more frequently, a piston-type pump.

The piston pump may include a piston cylinder connected to the hood, and a piston disposed within the piston cylinder that is reciprocated by a hand-drivable piston rod (see, e. g., U. S.

Patent No. 9,971,952). In general, a manual breast pump consists of a plunger that freely slides within an outer cylinder. A seal is fitted around the outside of the plunger to seal against the inner surface of the outer cylinder. In this way, the plunger can slide within the outer cylinder to form a pump stroke. A breast flange or funnel is fluidly connected to the outer cylinder. The mother applies suction to the breast by supporting the breast flange against the breast and pulling the plunger outwardly from the outer cylinder. Suction is created in the space which is expanded within the inside of the outer cylinder. The removed milk may

be retained within the interior space of the outer cylinder or alternatively may be pumped out into a baby bottle or nursery bag that is connected to the outer cylinder.

Motor-driven pumps typically either have a separate vacuum pump attached to the hood by tubing, or the motor is built into the hood assembly itself. Central or portable vacuum units can be used. Motor-driven pumps can be either battery operated or AC or DC powered devices. Any form of vacuum pump can be used, see, e. g., U. S. Patent No. 5,970,999; including micropumps, see, e. g., U. S. Patent No. 6,003,737.

The action or amount of negative pressure (vacuum) generated by the pump can be continuous or variable (e. g.,"alternating" or"rhythmic"); timing and vacuum pressure can be regulated by control dials or by a programmable component, e. g., a microprocessor or a computer (e. g., a"PC").

Figure 1 illustrates a motor-driven breast pump system 10 comprising a regulator 12, tubing 14, a reservoir 16, and a breast pump flange 18. The regulator 12 is connected to a vacuum source 21, which can be a local (portable) unit or a central vacuum system as common in offices and hospitals. An output line 23 is connected to the tubing 14 of the regulator 12. The regulator 12 can also have a suction level gauge 25 and an on-off switch 27.

Figure 2 illustrates a side elevational view of the regulator 12. The regulator 12 can have a wall connection 30, which is adapted to be connected to the vacuum source 21 via a wall connector (not shown). A bacteria filter 32 can be connected between the regulator 12 and the output line 23.

Figure 3 illustrates a schematic diagram of a exemplary two-stage regulation system of the regulator 12. A fixed regulator 34 receives a suction from the vacuum source 21, which typically comprises a pressure ranging from 320 to 720 mm Hg. The fixed regulator 34 regulates the pressure to a constant pressure within a range of 260 mm Hg to 300 mm Hg.

The fixed regulator 34 provides this regulated pressure to a timing circuit (not shown) of the regulator 12. The pressure from 260 mm Hg to 300 mm Hg can be supplied by the fixed regulator 34, is output to the adjustable regulator 36. The adjustable regulator 36 adjusts the pressure to a range of 0 mm Hg to 300 mm Hg, depending upon the position of the suction level gauge 25. A safety relief valve 38 is adapted to maintain a pressure output from the adjustable regulator 36 below 300 mm Hg. The maximum pressure allowed by the safety relief valve 38 is preferably set within a range of 260 mm Hg and 300 mm Hg. The timing circuit (not shown) of the regulator 12 can be fixed to provide suction intervals of approximately one second to the breast pump flange 18. In

this way, the fixed-suction from the vacuum source 21 is regulated and modulated by the regulator 12.

The breast pump flange 18 can be driven by the modulated pressure from the regulator 12 and, if in this configuration, does not require any electrical input. The breast pump flange 18 can have both a soft material and a configuration optimized to mimic the suckling produced by a nursing baby. The breast pump flange 18 can be, e. g., the Soft Cup FunnelTM and the tubing 14 and reservoir 16 can comprise a Breast Pump KitTX manufactured by White River Concepts, San Clemente, CA. The regulator 12 can be a VacutronTX suction regulator (Allied Health Care Products, St.

Louis, MO). An example of a breast pump having a soft breast pump flange is described in U. S. Pat. No. 4,772,262.

One embodiment of the system comprises an electronic controller that causes the regulator 12 to perform a series of different suck/release patterns that closely simulate the habits of a nursing baby during an average feeding. By mimicking these patterns, the breast is allowed ample time to refill the ducts after the suck/swallow has occurred. By approximating these patterns, the mother is able to stimulate further production of her milk by vigorously stimulating her nipples and emptying more milk in a shorter period of time.

This method would also apply to suction at the breast using

the wall suction regulator along with a breast cup. The electronic controller can be part of an overall control component, such as a microprocessor, that coordinates the functioning of the pump, vacuum, and the auditory stimulus apparatus.

The interface between the wall suction and the lactating breast can be a soft cone molded in a soft silicone or thermoplastic rubber. The cone latches onto the breast and performs compression patterns that are similar to those of a breastfeeding baby. In order to ensure that compression is accomplished directly over the lactiferous sinuses, an accurate match must occur between the soft cone and the woman's breast.

Figure 4 illustrates a schematic of the internal pump enclosure 50 of a motor-driven pump incorporating a sensor 55 according to the present invention. The breast pump flange 18 is connected to a vacuum port 60 of the pump. If the breast pump overflows, it is possible for breastmilk or other fluids to enter the internal pump mechanism 50. Breast pumps have used floating ball valves and other methods to prevent entry of the breastmilk into the internal pump mechanisms, but each of these techniques can be ineffective.

Therefore, instead of, or in addition to other overflow prevention techniques, the present invention includes a sensor

55 at the inlet of the pump enclosure 50. The sensor 50 may be an infrared sensor, a motion sensor, a laser sensor, or any other sensor that may detect the presence of breastmilk entering the pump enclosure 50. The sensor 50 is connected to the pump controls 70, typically a PC board, and automatically shuts down the pump if any breastmilk is detected entering the pump enclosure 50. By shutting down the pump immediately upon detection of breastmilk, contamination may be reduced or eliminated.

Even with the sensor 55, it is possible for breastmilk to enter the pump enclosure 50, although the amount should be minimized. When breastmilk does enter the internal enclosure, the pump should be cleaned. Also, if a pump is not equipped with the overflow sensor, the likelihood of needing internal cleaning is increased.

The present invention automates the process of internal cleaning to simplify the procedure, thereby ensuring consistent results and simplifying the procedure. Automating the cleaning allows the pump to be cleaned at any time and by any person, eliminating the need for a specially trained technician. The automated flushing cycle may be control by the pump controls 70. The automated flushing cycle is activated by a button 77 on the control panel 75 of the breast pump, as seen in Figure 5. The user is alerted to the

possible need for the automated flushing cycle by illumination of an overflow indicator light 79. The overflow indicator light 79 may be electrically connected to the sensor 55 so that when the sensor 55 detects the presence of breastmilk in the pump mechanism, the overflow indicator light 79 is illuminated. The control panel 75 also includes a master on/off switch 81, and may contain indicators for suction level 83 and timing 85. Of course, the inclusion of elimination of controls from the control panel 75 is a matter of design choice.

The automated flushing cycle comprises a series of specifically timed suck and release cycles and suction level which systematically pull an appropriate amount of cleansing fluid through the pump mechanism to ensure proper cleaning and removal of all breastmilk residue. The cleansing fluid may be hot water or any other appropriate cleaner. One embodiment of the automated flushing cycle is illustrated in Figure 6. The process 100 of the automated flushing cycle begins at a start state 105. Proceeding to state 110, the process 100 establishes a suction level at which the autoflush feature initially operates. The suction level effects the amount of cleansing fluid drawn into the pump mechanism for any given time period. The number of cycles, suction level, and cycle

timing may be predetermined and stored within the memory of the breast pump electronics.

Proceeding to state 115, the process 100 initializes a suction cycle timer and applies the suction. The suction cycle timer is an indication of how long to apply suction to draw the cleansing fluid through the pump mechanisms. Each phase of the process 100 may use a different amount of time for the suction cycle. The suction cycle time is predetermined to optimize the cleansing process.

Proceeding to state 120, the process 100 determines if the suction cycle timer has expired. If the suction cycle timer has not expired, the process 100 proceeds along the NO branch in a loop and returns to state 120. The process 100 remains in this loop until the suction cycle timer expires, at which point the process 100 proceeds along the YES branch to state 125.

In state 125, the suction is removed and no cleansing fluid is drawn into the pump mechanism. The process then proceeds to state 130 and sets a timer for the release cycle. The timer counts the amount of time the pump mechanism does not draw cleansing fluid and varies from cycle to cycle.

Proceeding to state 135, the process 100 determines if the release cycle timer has expired. If the release cycle timer has not expired, the process 100 proceeds along the NO branch

in a loop and returns to state 135. The process 100 remains in this loop until the release cycle timer expires, at which point the process 100 proceeds along the YES branch to state 140.

In state 140, the process 100 determines if additional suction and release cycles are present. A typical automated flush system has several cycles of suction and release. If additional cycles are present, the process 100 proceeds along the YES branch back to state 110 where the suction level of the next cycle is set. The process then continues as described above until returning to state 140.

Returning to state 140, if no additional cycles are present, the process 100 proceeds along the NO branch to state 145. In state 145, the process 100 sets a timer for a dry pump run and activates the pump. The pump is run for this specified period of time to thoroughly dry the passageways throughout the pump system.

Proceeding to state 150, the process 100 determines if the dry pump run timer has expired. If the dry pump run timer has not expired, the process 100 proceeds along the NO branch in a loop and returns to state 150. The process 100 remains in this loop until the dry pump run timer expires, at which point the process 100 proceeds along the YES branch to an end state 155.

The automated flushing cycle uses a series of predetermined, or preprogrammed timing sequences to flush the pump mechanism. In one embodiment of the invention, the timing sequences are as follows:

Cycle Suction Time Suction Level Release Time (seconds) (inches Hg.) (seconds) 1 60 2 60 2 45 4 45 3 30 6 30 4 15 8 15 Numerous variations and modifications of the invention will become readily apparent to those skilled in the art. Accordingly, the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The detailed embodiment is to be considered in all respects only as illustrative and not restrictive and the scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.