Breast pump unit and method of operation

Abstract

A method for operating a breast pump unit (10) for expressing human breast milk and a breast pump unit (10). The breast pump unit (10) comprises a pump assembly (26) for generating vacuum pressure, a reservoir (24) for receiving breast milk, and a breast shield (11) for sealingly applying to a breast to be pumped. The breast shield (11) comprises a flexible inner chamber (15) for receiving a nipple of the breast and a second chamber (16), in particular an outer chamber extending around the outside of the inner chamber (15) and at least partially surrounding the nipple inserted into the inner chamber (15). The method comprises a cycle comprising: evacuating the inner chamber (15) and the reservoir (24) to a first vacuum pressure by means of a pump assembly (26); connecting a second chamber (16) to the pump assembly (26) and the reservoir (24), and evacuating the second chamber (16) to a second vacuum pressure, wherein the second vacuum pressure is higher than or greater than the first vacuum pressure; and at least partially releasing the vacuum of the second chamber (16) to a lower vacuum pressure, in particular lower than the first vacuum pressure.

Description

[0001] Cross-reference of priorities

[0002] This application claims priority from Australian Provisional Patent Application No. 2020900501 filed on February 21, 2020, the contents of which are deemed to be incorporated into this specification by reference. Technical Field

[0003] The present invention relates to a breast pump or a breast pump unit for expressing human breast milk and to a method of operating a breast pump or a breast pump unit.In the following, throughout the description reference will be made to a breast pump unit rather than to a breast pump or a breast pump unit. Background Art

[0004] The following discussion of the background to the invention is intended to assist in understanding the invention. However, it should be appreciated that it is not an acknowledgement or admission that any aspect of the discussion was part of the common general knowledge as at the priority date of the application.

[0005] Breast pump units are known in the art and comprise a manually operated unit and a motor drive unit. The motor drive unit can be connected to a mains power source or can be battery-operated. The motor drive unit comprises a vacuum pump and one or two breastshields for placement over one or both breasts of a mother. Breast pump units are intended to simulate the way a baby suckles on a mother's breast and, therefore, use vacuum to pump in a cyclical manner to apply and release pressure to the breast and nipple through the breastshield, creating a vacuum within the or each breastshield to extract milk from the mother's breast. The breast pump unit comprises a milk collection container in which milk extracted from the mother's breast can be captured and stored for later use.

[0006] Breast shields themselves are available in a number of different styles designed to ensure a comfortable fit on breasts of varying sizes and shapes. However, a common feature of breast shields is their flexible nature, which allows them to pulsate or pulse when in contact with the nipple and, in some cases, the breast around the nipple to extract milk. That is, the breast shield is flexible, at least in the portion of the breast shield where the nipple is inserted, so that the nipple is cyclically squeezed and released to facilitate milk expression. The pulsation is created by generating and releasing a vacuum within the breast shield.

[0007] Generally, the capacity of the vacuum pump will determine the level of vacuum created within the breastshield. Furthermore, the capacity of the vacuum pump will determine how quickly the desired vacuum level is achieved. Therefore, a larger vacuum pump can deliver a greater vacuum more quickly than a smaller one. However, for breast pump units, space and weight are factors in selecting a vacuum pump, as are energy usage (primarily for battery-operated units) and noise generation. For these parameters, a smaller vacuum pump is generally preferred.

[0008] One example of a method of operating a breast pump unit is disclosed in EP 3 027 240 in the name of Koninklijke Philips NV, which discloses an apparatus and method for evacuating a system suitable for use in a breast pump device. The system of EP 3 027 240 is intended to generate an increased vacuum level than could be achieved by a vacuum pump alone. The system generates a vacuum in a pressure chamber (e.g., a milk collection bottle) and a separate pressure tank by connecting the inlet of the vacuum pump to the pressure chamber and the pressure tank, and connecting the outlet of the vacuum pump to atmosphere. The vacuum pump evacuates both the pressure chamber and the pressure tank to the same vacuum level. When the maximum vacuum level has been reached, the system of EP 3 027 240 switches the outlet of the vacuum pump to connect to the inlet of the pressure tank, so that the pressure at the outlet of the vacuum pump is at the vacuum level generated in the pressure tank, rather than at atmospheric pressure. This allows the vacuum pump to generate an increased vacuum level in the pressure chamber, and therefore, allows the system to generate a greater vacuum level than would be possible with the vacuum pump alone. When the vacuum is to be released, the release valve is triggered to vent both the pressure chamber and the pressure tank to atmosphere.

[0009] Thus, the system of EP 3 027 240 is intended to enable vacuum pumps that are not rated to produce such vacuum levels to produce a higher or greater vacuum, and therefore, to allow the use of smaller and less expensive vacuum pumps. However, a disadvantage of the system of EP 3 027 240 is that both a pressure chamber and a pressure tank are required to achieve an increase in vacuum pressure that exceeds that which can be produced by the vacuum pump alone. When used in a breast pump device, the tank undesirably increases complexity and bulk.

[0010] The present invention aims to provide an improved breast pump unit and method of operating a breast pump unit. Summary of the Invention

[0011] According to the present invention, there is provided a method for operating a breast pump unit for expressing human breast milk, the breast pump unit having:

[0012] a. a pump assembly for generating vacuum pressure,

[0013] b. a reservoir for receiving breast milk, and

[0014] c. a breast shield for sealingly applying to a breast to be pumped, the breast shield comprising a flexible inner chamber for receiving a nipple of the breast and a second chamber, in particular an outer chamber extending around the outside of the inner chamber and at least partially surrounding the nipple inserted into the inner chamber,

[0015] The method comprises a cycle characterized by the following steps, in the following order:

[0016] i. evacuating the inner chamber and the reservoir to a first vacuum pressure by the pump assembly,

[0017] ii. connecting the second chamber to the pump assembly and the reservoir, and evacuating the second chamber to a second vacuum pressure, wherein the second vacuum pressure is higher than the first vacuum pressure, and

[0018] iii. At least partially releasing the vacuum of the second chamber to a lower pressure, in particular lower than the first vacuum pressure.

[0019] For the purpose of breast milk expression, the inner chamber is flexible so that it can compress or squeeze a nipple inserted therein. The cyclic compression and release of the nipple by the method of the present invention helps improve breast milk expression in terms of both expression efficiency and comfort experienced by the mother.

[0020] The inner chamber can be formed from a flexible liner including an entry portion for receiving a nipple. In some forms of the present invention, the inner diameter of the entry portion is smaller than the outer diameter of a mother's nipple used with the breast pump unit. This means that once the nipple is inserted into the entry portion, the nipple is naturally compressed or squeezed by the liner in the resting or relaxed state of the inner chamber. With the method of the present invention, this natural compression applied to the nipple can be reduced or completely released by the vacuum introduced into the second chamber in step ii above, causing the inner chamber, and in particular the entry portion, of the inner liner, to expand. Thus, the application and release or reduction of this vacuum can impart a cycle of compression and relaxation to the nipple for the purpose of breast milk extraction. In this form of the invention, prior to initiating the method of the present invention for breast milk expression, initial insertion of the nipple into the entry portion of the liner can be facilitated by initially introducing a vacuum into the second chamber to expand the entry portion. Thereafter, the vacuum can be released or reduced to allow the inner liner to engage or clamp the nipple. The inner liner can be annular or tubular.

[0021] In other forms of the invention, the inner diameter of the access portion is about the same as or larger than the outer diameter of a mother's nipple used with the breast pump unit. This means that once the nipple is inserted into the access portion, the liner needs to be retracted to compress or squeeze.

[0022] The second chamber may be hard or rigid, but should at least be less flexible or more inflexible than the inner chamber.

[0023] The first vacuum pressure applied to the inner chamber is suitable for drawing or extracting milk through the nipple for discharge into the reservoir. The first vacuum pressure can be a constant pressure, and in prototype testing to date, a pressure of approximately -200 mmHg has been used. The vacuum pressure within the second chamber can cycle or fluctuate around the first vacuum pressure. The first vacuum pressure will tend to collapse or contract the inner chamber until the vacuum pressure within the second chamber reaches the same pressure as the first vacuum pressure. Thereafter, when the vacuum pressure within the second chamber rises to the second vacuum pressure, the vacuum pressure within the second chamber will tend to expand the inner chamber, particularly the entry portion of the inner liner, thereby relieving pressure on the nipple. It has been found that compressing and releasing the nipple in this manner promotes good milk flow through the nipple, reduces the tendency for milk duct blockage and edema formation, and provides a good level of comfort for the mother. These are all very beneficial results.

[0024] Compared to the second chamber being evacuated relative to the atmosphere, the method according to the present invention advantageously allows for a vacuum to be quickly and efficiently generated in the second chamber due to the second chamber being connected to the pump assembly and the reservoir. Through this connection, the second chamber is immediately or quickly evacuated to a first vacuum pressure, which is the vacuum level within the reservoir, and therefore, the pump assembly does not need to evacuate the second chamber to this level. Instead, the pump assembly only needs to evacuate the second chamber from the first vacuum pressure to the second vacuum pressure. This saves time and pump workload. For example, the first vacuum pressure in the inner chamber can be set to approximately -200 mmHg, while the second vacuum pressure in the second chamber can be set to approximately -380 mmHg. To achieve -380 mmHg, the second chamber can first be evacuated to -200 mmHg via the connection of the second chamber to the pump assembly and the reservoir, without requiring any pump assembly workload to evacuate the second chamber to this level. The pump assembly then only needs to increase the vacuum level in the second chamber from -200 mmHg to -380 mmHg.

[0025] It is to be expected that there will be a loss or drop in vacuum pressure in the reservoir when the second chamber is connected to the reservoir, but this is minimised by the fact that the volume of the reservoir is much greater than the volume of the second chamber. The normal size of breast milk reservoir used with prior art breast pump units is expected to have a volume that meets this requirement of being much greater than the volume of the second chamber.

[0026] The method according to the present invention also advantageously allows for a faster and more efficient reduction of the vacuum level in the second chamber by reversing the process of connecting the second chamber to the reservoir, whereby the larger second vacuum pressure is immediately or rapidly reduced to the first vacuum pressure without requiring any pumping effort. When the second chamber is connected to the reservoir, there will be a slight increase in pressure in the reservoir, but again, this is minimized because the volume of the reservoir is much larger than that of the second chamber.

[0027] Once the vacuum in the second chamber is at the first vacuum pressure of the reservoir, the pump assembly can be operated to further reduce the vacuum as needed, such as to atmospheric pressure. Thus, the pump assembly only needs to reduce the vacuum from -200 mmHg to atmospheric pressure, rather than from -380 mmHg to atmospheric pressure.

[0028] As described above, the first vacuum pressure may be a substantially constant pressure, i.e., -200 mmHg. Thus, step i may comprise bringing the inner chamber from atmospheric pressure to -200 mmHg, and then maintaining this vacuum level for the duration of operation of the breast pump unit. Thus, the method of the present invention may be operable to evacuate the second or outer chamber of the breast pump unit from a vacuum level, such as atmospheric pressure, which is less than the first vacuum pressure, to a second vacuum pressure level, which is greater than the first vacuum pressure. The method of the present invention may thus switch the connection of the second chamber between connection to the reservoir and connection to the atmosphere, and advantageously, utilize the vacuum in the reservoir for both vacuum generation and vacuum release, thereby increasing the speed of vacuum generation and release and reducing the workload of the pump.

[0029] The examples given above show that the first vacuum pressure is approximately -200 mmHg and the second vacuum pressure is approximately -380 mmHg. However, the vacuum pressure can be set to any level, and thus, for example, the second vacuum pressure can be at least 25% higher than the first vacuum pressure, or the second vacuum pressure can be approximately 75% higher than the first vacuum pressure. What is required is the difference between the vacuum pressures, and therefore other ratios or values ​​can be used. Other ratios or values ​​may be suitable, for example, for breast or nipple stimulation before breast milk is expressed, i.e., before the so-called let-down reflex. Suitable ranges for the first vacuum pressure include -70 mmHg to -350 mmHg, more preferably -120 mmHg to -200 mmHg. Suitable ranges for the second vacuum pressure include -150 mmHg to -480 mmHg, more preferably -250 mmHg to -380 mmHg.

[0030] The breast pump unit according to the present invention facilitates the generation of pulsations by generating a second vacuum pressure in the second chamber, wherein the second vacuum pressure is a higher or greater vacuum than the vacuum in the inner chamber. The rapid generation of the second vacuum pressure allows the inner chamber to expand, thereby partially or completely relieving the pressure applied to a nipple inserted into the inner chamber. This cycle of squeezing and releasing the nipple has a positive effect on breast milk expression and is believed to result in a massage effect that cleans the milk ducts and prevents or eliminates the formation of edema. This effect is believed to more closely simulate infant sucking than existing breast pump units. The breastshield can also be configured so that the generated pulsations are also applied to the areola, thereby also creating a massage effect on this part of the breast. Similarly, the measurable effect of massaging the areola is improved breast milk expression.

[0031] In some forms of the invention, once the second vacuum pressure has been reached, it can be immediately released to a lower pressure. However, in other forms of the invention, the second vacuum pressure is maintained substantially constant for a predetermined period of time in step ii before step iii. In either case, releasing the second vacuum pressure to the lower pressure allows the inner chamber to exert increased compression on the nipple by contracting the inner chamber under the influence of the first vacuum pressure. In other words, at least partially releasing the second vacuum pressure to the lower pressure allows the inner chamber to at least partially return to its relaxed or resting state.

[0032] In some forms of the present invention, the lower pressure of step iii is atmospheric pressure. However, in other forms of the present invention, the lower pressure of step iii is still a negative pressure that is reduced to less than the vacuum pressure of the inner chamber, or the negative pressure is reduced but greater than the vacuum pressure of the inner chamber. From an operational perspective, reducing the second vacuum pressure to atmospheric pressure in step iii is convenient and relatively easy. However, the present invention is being developed to accommodate a wide range of physical parameters, such as those related to breast and nipple size and maternal sensitivity and comfort, so reducing the second vacuum pressure to atmospheric pressure in step iii is not always desirable.

[0033] Although the pressure levels discussed above can be varied to achieve the most effective breast milk expression, the time periods for each step can also be varied. In some forms of the present invention tested so far, beneficial results have been achieved when the duration of step i is approximately 540ms, the duration of step ii is approximately 440ms, and the duration of step iii is approximately 540ms. In some forms of the present invention, the cumulative duration of steps ii and iii can be within the range of approximately 900ms (54 cycles per minute) + / - 200ms. This cumulative duration can also be applied when the cycle includes a time period in which the second vacuum pressure is maintained substantially constant in step ii before step iii. During the current testing, the preferred ratio of the durations of steps ii and iii was between 3 / 7 and 4 / 6. These time periods can of course be varied as needed and according to the advantageous vacuum levels and time periods that further testing has revealed for application.

[0034] In some forms of the invention, the pump assembly comprises a single vacuum pump, and the method of operating a breast pump unit according to the invention comprises a valve assembly, such as a switching valve, in particular a solenoid valve, to connect the inner chamber and the reservoir in series to the inlet of the vacuum pump and the second chamber to atmosphere in step i, and to switch the valve to connect the second chamber to the inlet of the vacuum pump and the inner chamber and the reservoir to the outlet of the vacuum pump in step ii. Step iii may return the switching valve to the position in step i.

[0035] In another form of the invention, the pump assembly comprises a single vacuum pump, and a method of operating a breast pump unit according to the invention comprises: in step i, connecting the inner chamber and the reservoir in series to the inlet of the vacuum pump via a first valve, and connecting the second chamber to atmosphere via a second valve, and in step ii, closing the first and second valves, connecting the inner chamber and the reservoir in series to the outlet of the vacuum pump via a third valve, and connecting the second chamber to the inlet of the vacuum pump via a fourth valve. Step iii may return the first and second valves to their respective positions in step i.

[0036] In some forms of the invention, the pump assembly comprises a pair of vacuum pumps arranged such that the inner chamber and the reservoir are connected in series to an inlet of a first of the vacuum pumps, and the second chamber is connected via a first valve to an inlet of a second of the vacuum pumps, a pressure line extending between the inlet of the first vacuum pump and the outlet of the second vacuum pump, and the pressure line comprising a second valve, and a method of operating a breast pump unit according to the invention comprises, in step i, opening the first valve to atmosphere and closing the second valve to the fluid passage, operating the first pump to evacuate the inner chamber and the reservoir to a first vacuum pressure, and, in step ii, closing the first valve to atmosphere and opening the second valve to the fluid passage, and operating the second pump to evacuate the second chamber.

[0037] It will be apparent that the method of the invention may be performed with various arrangements of vacuum pumps and valves.Specific examples are provided in the accompanying drawings.

[0038] It will also be apparent that the present invention can be implemented in a breast pump unit for expressing human breast milk, the breast pump unit having:

[0039] a. Vacuum pump, which is used to generate pressure,

[0040] b. a reservoir for receiving breast milk, and

[0041] c. a breast shield for applying in a sealed manner to a breast to be pumped, the breast shield having an inner chamber for receiving the nipple of the breast and a second chamber, in particular an outer chamber extending around the outside of the inner chamber and at least partially surrounding the nipple inserted into the inner chamber,

[0042] The breast pump unit can be operated in a cycle in which:

[0043] i. The vacuum pump evacuates the inner chamber and the reservoir to a first vacuum pressure,

[0044] ii. connecting the outer chamber to a vacuum pump and a reservoir so that the outer chamber is evacuated to a second vacuum pressure, wherein the second vacuum pressure is higher than the first vacuum pressure, and

[0045] iii. The vacuum in the outer chamber is at least partially released to a lower pressure, in particular below the first vacuum pressure.

[0046] In a breast pump unit according to the present invention, the inner chamber may be defined by a flexible inner liner including an entry portion for receiving a nipple, and the second chamber may be defined by a hard or rigid outer liner, the inner liner and the outer liner defining the second chamber therebetween. The inner diameter of the entry portion may be smaller than the outer diameter of a nipple used with the breast pump unit, and the entry portion may expand when a vacuum is introduced into the inner chamber.

[0047] In some forms of the invention, the vacuum pump may have an inlet and an outlet, and the breast pump unit may include a valve assembly interposed in pressure lines extending from the inlet and the outlet. The valve assembly is operable to switch the inner chamber and the reservoir from a pressure connection with the inlet of the vacuum pump to a pressure connection with the outlet of the vacuum pump, and to switch the outer chamber from a pressure connection with the outlet of the vacuum pump to a pressure connection with the inlet of the vacuum pump. The valve assembly may be an on-off valve, such as a 3 / 3 solenoid valve or a 4 / 3 solenoid valve. Alternatively, the valve assembly may include four valves, each valve being provided in a separate pressure line. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figures 1 to 3 A breast pump unit for expressing human breast milk is schematically shown.

[0049] Figure 4 is Figure 1 Graph of the vacuum pressure generated in the inner and outer chambers of a breast pump unit.

[0050] Figures 5 to 10 An alternative breast pump unit for expressing human breast milk is schematically shown. DETAILED DESCRIPTION

[0051] Figures 1 to 3 A breast pump unit 10 for expressing human breast milk is schematically shown. Breast pump unit 10 includes a breastshield 11 having a flexible, annular inner liner 12 and a hard or rigid, annular outer liner 13. Inner liner 12 defines an inner chamber 15 for receiving the nipple of a breast, and outer liner 13 extends around inner liner 12 and defines an outer chamber 16 extending around the outside of inner chamber 15. Inner liner 12 and outer liner 13 are connected at each end in a sealing manner, allowing a vacuum to be created in outer chamber 16. Inner liner 12 includes a funnel-shaped portion 18 for sealing against the surface of a mother's breast and a tubular entry portion 20 for receiving the nipple. The inner diameter of portion 20 is intended to be smaller than the outer diameter of a nipple inserted into portion 20, so that portion 20 compresses or squeezes the nipple when inner liner 12 is in a resting or relaxed state. As will be explained later herein, the compressive or squeezing pressure applied to the nipple by portion 20 of the inner liner 12 can be reduced or relieved by the vacuum introduced into the outer chamber 16. For the purpose of breast milk extraction, the nipple can be cyclically compressed and relaxed by cyclically varying the pressure or vacuum level within the outer chamber 16. Furthermore, when the breastshield 11 is applied to a breast, the funnel 18 will rest against the areola of the breast, and the vacuum introduced into the outer chamber 16 will also cause the funnel 18 to move or vibrate over the areola, thereby massaging the areola and assisting in the initiation of milk expression and generally improving breast milk expression.

[0052] The inner liner 12 has an evacuation port 22 around which the outer liner is sealed. The evacuation port 22 is connected to a reservoir 24, which in the illustrated embodiment is a collection reservoir for receiving breast milk. The reservoir 24 is connected to a vacuum pump 26 via a valve 28. The valve 28 is connected to an inlet 29 and an outlet 30 of the vacuum pump 26 and is Figure 1 In the orientation of the valve 28 shown by the arrow, the reservoir 24 is connected to the inlet 29 of the valve 28 , and the outlet 30 of the valve 28 is connected to the atmosphere via a one-way check valve 34 .

[0053] However, in Figure 1 In the orientation of the valve 28 in the middle, the evacuation port 36 of the outer liner 13 is also connected to the pressure pipeline 35, and the fluid (air) extracted from the inner chamber 15 and the reservoir 24 by the vacuum pump 26 and discharged through the outlet 30 of the pump 26 is discharged to the atmosphere through the check valve 34.

[0054] Thus, the vacuum pump 26 creates a predetermined level of vacuum in each of the internal chamber 15 and the reservoir 24. In tests to date, one predetermined level has been -200 mmHg.

[0055] Once the selected predetermined vacuum level is reached, valve 28 switches to Figure 2 . In this position, the pressure line 35 is connected to the inlet 29 of the vacuum pump 26, and the outlet 30 of the vacuum pump 26 is connected to the reservoir 24 and the inner chamber 15. Therefore, the outlet 30 of the vacuum pump 26 almost instantly reaches the predetermined vacuum level to which the reservoir 24 and the inner chamber 15 have been pumped from atmospheric pressure. Such a switch also causes the outer chamber 16 to be evacuated to the predetermined vacuum level almost instantly. The vacuum pump 26 can now continue to evacuate the outer chamber 16 to a vacuum level that is greater or higher than the vacuum level of the inner chamber 15 and the reservoir 24. The suction or vacuum pressure applied to the pressure line 35 also causes the valve 34 to be firmly closed, so that the pressure line 35 is closed to the atmosphere. In prototype testing to date, a greater or higher vacuum level to which the outer chamber 16 has been evacuated is -380 mmHg.

[0056] When valve 28 is Figure 1 Switch to the location shown in Figure 2 In the position shown in FIG, there will be a pressure loss or drop in the reservoir 24 and the inner chamber 15, but this is minimized because the volumes of the reservoir 24 and the inner chamber 15 are much greater than the volume of the outer chamber 16. The ratio can be in the range of 1:10 or more.

[0057] There will also be a small loss of pressure as the breast milk enters the reservoir 24 , but again this is minimised as the volume of the reservoir 24 and inner chamber 15 is much greater than the volume of the outer chamber 16 .

[0058] Figure 3 Another position of the valve 28 is shown in which each of the inner chamber 15, the outer chamber 16 and the reservoir 24 are isolated from the vacuum pump 26 so that the generated vacuum pressure is maintained or held for a predetermined period of time. Once the predetermined period of time has expired, the valve 28 can be switched back to Figure 1 In the location. Figure 1 In the vacant position, the inner chamber 15 and reservoir 24 will be returned to direct connection with the inlet 29 of the vacuum pump 26 and will therefore be returned to the previously described predetermined vacuum level, while the outer chamber 16 will be returned to atmospheric pressure. The loss of pressure in the reservoir 24 is assisted by draining fluid from the reservoir 24 through the check valve 34.

[0059] Figures 1 to 3 The operating sequence of the breast pump unit 10 shown in FIG can be performed cyclically to generate a pulsating motion in the breast shield 11 to extract breast milk. Figure 4 An approximate graph of the pressures generated in the inner chamber 15 and the outer chamber 16 is shown in FIG. The graph plots vacuum pressure (Y-axis) versus time (X-axis). The line labeled "inner chamber 15" begins at atmospheric pressure and decreases to a substantially constant negative pressure or vacuum pressure. As illustrated, the line labeled "outer chamber 16" is cyclic.

[0060] Figure 4 The section 1 of the cycle shown as S1 is when the valve 28 is in Figure 1 The inner liner is evacuated from atmospheric pressure to a predetermined pressure level, such as -200 mmHg. In section 1, the outer chamber 16 within the outer liner 13 is maintained at atmospheric pressure. In section 2 (S2), the valve 28 has been switched to Figure 2 The position of the valve 28 causes the pressure in the outer chamber 16 to increase, for example to -380 mmHg. Importantly, the graph shows that the vacuum in the outer chamber 16 increases immediately from 0 mmHg to a vacuum of approximately -200 mmHg in the inner chamber 15, and then increases more gradually or slowly from -200 mmHg to -380 mmHg. This reflects that once the valve 28 is opened, the pressure in the outer chamber 16 increases, for example to -380 mmHg. Figure 1 Switch to Figure 2 , the outer chamber 16 is connected to the reservoir 24 via the inlet 29 of the vacuum pump 26, so that the outer chamber 16 is almost instantly brought from atmospheric pressure to a vacuum pressure of -200 mmHg within the reservoir 24. The graph also shows that the vacuum pump 26 then operates to further evacuate the outer chamber 16 to -380 mmHg, but this takes more time.

[0061] As mentioned above, when the valve 28 is switched to Figure 2 There will also be a slight pressure drop in the inner chamber 15 when the position is set, but the pressure drop may be relatively small. Figure 2 In section 3 (S3), valve 28 has been switched to Figure 3 The position of the outer chamber 16 is maintained so that the pressure in the outer chamber 16 does not increase or decrease. Finally, section 4 (S4) is when the valve 28 switches back to Figure 1 , thereby evacuating the outer chamber 16 to atmospheric pressure, but maintaining the inner chamber 15 under vacuum. In segment S4, the graph again shows an almost instantaneous decrease in vacuum pressure from -380 mmHg to -200 mmHg, which occurs due to connecting the outer chamber 16 to the reservoir 24 via the vacuum pump 26, so that the pressure in the outer chamber 16 is immediately or quickly reduced to the vacuum pressure in the reservoir 24 without requiring any pumping effort. Pumping effort is then required to evacuate the outer chamber 16 to atmospheric pressure, as shown in segment S4, which requires more time.

[0062] Importantly, this cycle does not return the inner chamber 15 to atmospheric pressure, but rather the vacuum level within the inner chamber 15 remains substantially constant once the inner chamber 15 has initially been evacuated. Figure 4 The constant vacuum pressure draws breast milk through the nipple and into the reservoir 24.

[0063] Regarding the effect of the breastshield 11 on the breast and nipple, as described above, the diameter of the inner liner 12 at the entry end, or at the tubular portion 20 into which the nipple is inserted, can be made smaller, potentially much smaller than the outer diameter of the nipple. This allows the inserted nipple to be compressed or squeezed when the inner liner 12 is in its relaxed state. This compression is maintained in section S1. However, when a vacuum is created in the outer chamber 16 in section S2, the tubular portion 20 reduces or releases the pressure on the nipple. This is because when the vacuum level created in the outer chamber 16 is greater than the vacuum level within the inner liner 12, the inner liner 12 expands and thereby exerts a gradually decreasing pressure on the nipple, until the vacuum level in the outer chamber 16 is sufficient to cause the inner liner 12 to effectively (at least partially) lose contact with the nipple surface, resulting in no compressive or squeezing pressure acting on the nipple. This arrangement is achieved by having the outer liner 13 be hard or rigid and the inner liner 12 be flexible. The vacuum cycle thus cyclically compresses and releases the nipple.

[0064] The compressive or squeezing pressure applied to the nipple is reduced or released for the portion of segment S2 when the vacuum level created in the outer chamber 16 exceeds the vacuum level created in the inner chamber 15, and for the entire segment S3. In segment 4, the vacuum pressure within the outer chamber 16 is reduced to a point below the vacuum pressure of the inner chamber 15, thereby allowing the portion 20 of the inner liner 12 to return to a compressive or squeezing position against the nipple.

[0065] from Figure 4 It will be appreciated that once the pressure reaches a predetermined level, the vacuum applied to the inner chamber 15 is substantially constant. This vacuum draws milk from the nipple and transfers it to the reservoir 24. It will also be appreciated that the cyclic vacuum applied to the outer chamber 16 causes the tubular portion 20 to expand and contract, thereby releasing and then squeezing the nipple inserted within the tubular portion 20. This effect of releasing and squeezing the nipple cyclically causes milk to be expressed from the breast.

[0066] In addition, the outer liner 13 also applies and releases pressure to the inner liner 12 at the funnel-shaped portion 18 of the inner liner 12, and applying and releasing pressure at the funnel-shaped portion 18 tends to massage the areola portion of the breast, which is also understood to assist in both initiating milk expression (commonly known as "letting down") and continuing milk expression.

[0067] Figure 4 The duration of the different segments of the cycle illustrated in can be selected as needed, or as indicated by tests to be the best choice. In some tests carried out so far, the time periods for segments S1 to S4 were 540ms, 440ms, 300ms and 540ms.

[0068] The present invention differs from the device of EP 3 027 240 at least in the operation of the system to maintain the pressure within the inner chamber 15 and reservoir 24 as the pressure within the outer chamber 16 varies between atmospheric pressure and maximum vacuum. Figures 1 to 4 The device facilitates pulsing of the vacuum level within the outer liner 13 to generate and release pressure on the nipple and areola of the breast. The device of the present invention advantageously benefits from the pressure initially generated in the reservoir 24, which is used to evacuate the outer chamber 16 to a pressure greater than the pressure in the inner chamber 15 and to return the pressure in the outer chamber 16 to atmospheric pressure. In this regard, when the evacuation port 36 of the outer chamber 16 is connected to the inlet 29 of the vacuum pump 26, the system of the present invention quickly equalizes the pressure in the outer chamber 16 to the pressure in the reservoir 24, and only at this stage does the pump 26 need to be operated to further increase the vacuum pressure in the outer chamber 16. Furthermore, when the vacuum level in the outer chamber 16 is to be released back to atmospheric pressure, reconnecting the outer chamber 16 to the outlet 30 of the pump 26 quickly reduces the pressure in the outer chamber 16 back to equal that in the reservoir 24, and only at this stage does the pump 26 need to be operated to further reduce the vacuum pressure in the outer chamber 16 (to atmospheric pressure). Advantageously, the increase in vacuum pressure within outer chamber 16 from atmospheric pressure to equal the vacuum pressure of reservoir 24 and then decrease from greater than the vacuum pressure of reservoir 24 back to equal the vacuum pressure of reservoir 24 occurs rapidly in both directions.

[0069] In addition, Figure 4Repressurizing or re-evacuating the reservoir 24 in section S4 is rapid because it is performed while the interior chamber 15 remains under vacuum, rather than starting from atmospheric pressure.

[0070] Still further, any air that leaks into the system is removed by the check valve 34 when the reservoir 24 is re-pressurized, and this can stabilize the cycle during extended periods of operation.

[0071] Figure 5 Shown Figures 1 to 3 The device is shown as a 4 / 3 solenoid valve, that is, a four-way, three-position directional control valve. Figure 5 shows how the valve 28 can be moved linearly about Figures 1 to 3 Switch between the described phases.

[0072] Figure 6 is another schematic diagram of an alternative arrangement using four separate valves. Figure 6 The breastshield 11 of the earlier embodiment is shown employed within a breast pump unit 50 comprising a reservoir 51 (milk bottle), a vacuum pump 52 , valves V1 to V4 and a one-way check valve 55 .

[0073] The valves V1 to V4 are controlled by a suitable control mechanism that can selectively open and close the valves. Figure 6 It is not shown in the figure, but can be easily obtained and understood by those skilled in the art.

[0074] The vacuum pump 52 has an inlet 56 and an outlet 57. Valves V1 to V4 operate to switch the inlet 56 and outlet 57 between the reservoir 51 and the outer chamber 16 of the breastshield 11. The breast pump unit 50 can be operated to generate a vacuum by first opening valves V1 and V4 and closing valves V2 and V3. Figure 4 In this state, the inner chamber 15 of the breastshield 11 and the reservoir 51 are connected to the inlet 56 of the pump 52, while the outlet 57 can be vented through the non-return valve 55. Therefore, the operation of the pump 52 evacuates the inner chamber 15 and the reservoir 51.

[0075] Once the predetermined pressure levels are reached in the internal chamber 15 and the reservoir 51, valves V1 and V4 may be closed, and valves V2 and V3 may be opened simultaneously. Alternatively, all valves V1 to V4 may be kept closed for a very short time, e.g., 5 to 10 ms, before opening valves V2 and V3, to ensure correct switching of pressures between the respective pressure lines controlled by valves V1 to V4.

[0076] This switches the pressure lines so that the outer chamber 16 of the breastshield 11 is connected to the inlet 56 of the pump 52, and the reservoir 51 and inner chamber 15 are connected to the outlet 57. This immediately and rapidly creates a vacuum in the outer chamber 16 to a level equal to that in the reservoir 51, wherein a very slight reduction in the vacuum occurs in the reservoir 51.

[0077] Compared with the single type solenoid valve shown in the previous figure, Figure 6 The use of four valves in produces the same results as described in relation to the breast pump unit 10, although the control of the four valves will be different and will employ different circuitry and hardware.

[0078] Figure 7 Is to achieve Figure 4 Another alternative arrangement is the same as the pressure graph shown in FIG, but Figure 7 The breast pump unit 70 of FIG. 1 employs a first vacuum pump 71 and a second vacuum pump 72, rather than a single vacuum pump as in the previous figures. Figure 7 In the embodiment, the inlet 74 of the vacuum pump 71 is connected to the reservoir 76 and the inner chamber 15 of the breastshield 11. The outlet 77 of the pump 71 is connected to the atmosphere.

[0079] The inlet 79 of the vacuum pump 72 is connected to the outer chamber 16 of the breastshield 11 , while the outlet 80 is connected to the atmosphere via a one-way check valve 81 .

[0080] A pressure line 82 extends between the inlet 74 of the pump 71 and the outlet 80 of the pump 72. A 2 / 2 solenoid valve 84 controls the pressure flow through the line 82.

[0081] Another 2 / 2 solenoid valve 85 is provided in the pressure line 86 on the inlet side of the pump 72 and controls the flow through the pressure line 86 into the atmosphere.

[0082] The positions of valves 84 and 85 are as follows: Figure 7 In the situation shown in FIG, both vacuum pump 71 and vacuum pump 72 can be operated simultaneously to have the following effect: pump 71 evacuates the inner chamber 15 and reservoir 76, while pump 72 draws air through valve 85 and exhausts this air back to atmosphere through valve 81. It will be appreciated that pump 72 need not be operated during the initial operation of pump 71 to evacuate the inner chamber 15 and reservoir 76, but an alternative is to have pump 72 run continuously. This may be advantageous where the breast pump unit 70 is operated with short cycle times, which may be disadvantageous where the pump 72 is periodically switched on and off. Figure 7 The state achieved is Figure 4 Segment S1.

[0083] Once the vacuum pressure in the inner chamber 15 and reservoir 76 reaches a predetermined vacuum level (e.g. -200 mmHg), valves 84 and 85 are switched so that valve 84 facilitates or allows flow from the outlet 80 of the pump 72 to the inlet 74 of the pump 71 and valve 85 is closed to prevent air from venting to the atmosphere. In these switched positions, the breast pump unit 70 enters Figure 4 The section S2 in which the outlet 80 of the pump 72 is connected to the inlet 74 of the pump 71 is immediately exposed to the vacuum pressure at the inlet 74. Therefore, the outer chamber 16 is also immediately exposed to this pressure. The pump 72 can then further increase the vacuum pressure in the outer chamber 16 starting from the vacuum pressure of the reservoir 76.

[0084] Once the vacuum in the outer chamber 16 reaches the desired greater vacuum pressure ( Figure 4 At the end of section S2 in the process), valve 84 can return to Figure 7 , into which the valve 85 has already been switched in section S2. The breast pump unit 70 is now in section S3.

[0085] Finally, to restore the vacuum level in the outer chamber 16 to atmospheric pressure, valves 84 and 85 are returned to Figure 7 , whereby the outer chamber 16 is evacuated to atmospheric pressure, but the inner chamber 15 remains under vacuum. Figure 7 With the valve in the correct position, the outer chamber 16 will immediately drop to the predetermined vacuum level currently in the reservoir 76 and once at that level, the pump 72 is operated to reduce the vacuum within the outer chamber 16 to atmospheric pressure.

[0086] Figure 8 Another alternative arrangement of a breast pump unit 90 is shown which uses the breast shield 11 of the previous figure. Figure 7 In addition to the 2 / 2 solenoid valve 84, Figure 8 The device and Figure 7 The breast pump unit 70 is very similar to that of Figure 7 The same reference numerals used in Figure 8 numeral 70 is used to indicate identical or common components between the respective breast pump unit 70 and breast pump unit 90 .

[0087] exist Figure 8 In the embodiment, vacuum is drawn from the inner chamber 15 of the breast shield 11 and from the reservoir 76 by the vacuum pump 71, and the 3 / 3 solenoid valve 92 is shown as being used for Figure 4 Valve 92 closes the path through pressure line 82 , and therefore if vacuum pump 72 is also running, vacuum pump 72 obtains air through pressure line 86 and exhausts the air through pressure line 82 to atmosphere through valve 92 .

[0088] Once the vacuum pressure in the inner chamber 15 and the reservoir 76 reaches a predetermined vacuum level, valves 85 and 92 can be switched so that valve 85 closes the pressure line 86 to atmosphere and valve 92 opens the pressure line 82 between the outlet 80 of the pump 72 and the inlet 74 of the pump 71. As with the previous embodiment, such movement of the valves causes the pressure at the inlet of the outer chamber 16 to switch to the pressure at the inlet 74 of the pump 71, and thus, the vacuum pressure within the outer chamber is immediately and rapidly reduced to the pressure within the reservoir 76. Continued evacuation of the outer chamber 16 by the pump 72 will continue to increase the vacuum level within the outer chamber 16. This represents Figure 4 Segment S2.

[0089] As soon as the vacuum in the outer chamber has reached the desired higher vacuum pressure, the valve 94 can be switched to the closed position, in which the pressure line 82 is closed again. This brings the breast pump unit 90 to Figure 4 Segment S3.

[0090] Finally, valves 85 and 92 can be returned to Figure 8 , the vacuum in the outer chamber 16 is vented by moving the outer chamber 16 to the position shown in FIG. 1 , whereby the outer chamber 16 is immediately reduced to the vacuum level currently in the reservoir 76 , and once at that level, the pump 72 can be operated to continue reducing the vacuum in the outer chamber 16 to atmospheric pressure.

[0091] Figure 9 1 shows another alternative breast pump unit 100 which employs the same vacuum pump 71 and reservoir 76 as the earlier embodiment, but where the second pumping means is a single stroke piston pump 102 in communication with a 2 / 2 solenoid valve 104 and a solenoid valve 106 .

[0092] Figure 9 Pictured Figure 4 The pressure curve diagram of FIG. 1 is in section S1 , and in this state the pump 102 has its piston 103 at the inlet end 108 .

[0093] When the vacuum level within the internal chamber 15 and the reservoir 76 reaches a predetermined level, valves 104 and 106 can each be switched to a closed position, and valve 84 can be switched to open the pressure line 110. Figure 10 1 shows a state in which the piston 103 of the piston pump 102 has traveled to the outlet port 112 to draw vacuum into the outer chamber 16. The stroke of the piston 103 in the pump 102 can, for example, generate a desired vacuum level in the outer chamber 16.

[0094] Once the desired vacuum level is established within the outer chamber 16, the valve 84 is returned to Figure 9 closed position and in Figure 4In section S3, the corresponding vacuum degree is kept constant.

[0095] When the outer chamber 16 is to be evacuated back to atmospheric pressure, valves 106 and 104 are returned to Figure 9 The valves 106 and 104 are in the open position, and the piston pump 102 can drive the piston 103 back to the inlet end 108 of the pump 102.

[0096] These figures illustrate the implementation of Figure 4 Various embodiments of pressure distribution within a breast shield are shown in FIG. Other arrangements may also be used. However, each of the illustrated embodiments facilitates expansion and contraction of the inner liner 12, and particularly the tubular portion 20 of the inner liner 12, to relieve and reapply pressure to a nipple inserted into the tubular portion 20. Each of these embodiments also facilitates a massaging effect on the areola of the breast, which testing has shown helps initiate milk expression and improves overall milk expression. Physical testing on nursing mothers has also shown that the way the breast shield moves provides improved comfort for the mother, making it more likely that the mother will express breast milk for a longer period of time rather than reverting to formula, to the benefit of the newborn baby.

[0097] When any or all of the terms "comprises," "comprising," "containing," or "having" are used in this specification (including the claims), these terms should be interpreted as specifying the presence of stated features, integers, steps, or components, but not excluding the presence of one or more other features, integers, steps, or components.

[0098] It will be appreciated by those skilled in the art that the invention described herein is susceptible to variations and modifications other than those specifically described. It should be understood that the invention includes all such variations and modifications that fall within the spirit and scope of the invention.

[0099] Future patent applications may be filed in Australia or overseas based on or claiming priority from the present application. It should be understood that the following provisional claims are provided by way of example only and are not intended to limit the scope of protection that may be claimed in any such future application. Features may be added to or omitted from the provisional claims later in order to further define or redefine one or more inventions.

Claims

1. A method for operating a breast pump unit for expressing human breast milk, the breast pump unit comprising: a. a pump assembly comprising a vacuum pump, the pump assembly being configured to generate a vacuum pressure, b. a reservoir for receiving breast milk, and c. a breast shield for applying in a sealed manner to a breast to be pumped, the breast shield having a flexible inner chamber for receiving a nipple of the breast and a second chamber, the second chamber being an outer chamber extending around the outside of the inner chamber and at least partially surrounding the nipple inserted into the inner chamber, The method comprises a cycle having the following steps, in the following order: i. evacuating the inner chamber and the reservoir to a first vacuum pressure by the pump assembly, ii. connecting the second chamber to the pump assembly and the reservoir, and evacuating the second chamber to a second vacuum pressure, wherein, The second vacuum pressure is higher than or greater than the first vacuum pressure, and iii. at least partially releasing the vacuum of the second chamber to a lower vacuum pressure than the first vacuum pressure. 2 . The method of claim 1 , wherein the first vacuum pressure is a substantially constant pressure.

3. The method of claim 1, wherein once the inner chamber has been evacuated to the first vacuum pressure, the second chamber is connected to the vacuum pump and the reservoir. The method of claim 1 , wherein the second vacuum pressure is at least 25% greater than the first vacuum pressure. The method according to claim 1 , wherein the second vacuum pressure is from −200 mmHg to −480 mmHg, and the first vacuum pressure is from −70 mmHg to −350 mmHg.

6. The method of claim 1 , wherein the inner chamber comprises an access portion into which a nipple is insertable, the access portion having a resting or relaxed state in which the access portion applies a compressive pressure to the nipple, and the access portion expands during step ii to reduce or completely release the compressive pressure.

7. The method of claim 6, wherein the entry portion returns to the resting or relaxed state during step iii.

8. The method according to claim 1, wherein the lower vacuum pressure in step iii is atmospheric pressure. 9 . The method of claim 1 , wherein before step iii, in step ii, the first vacuum pressure and the second vacuum pressure are kept constant for a predetermined period of time.

10. The method of claim 1, wherein the duration of step i is approximately 540 ms, the duration of step ii is approximately 440 ms, and the duration of step iii is approximately 540 ms.

11. The method according to claim 1, a. In step i, the inner chamber and the reservoir are connected in series to the inlet of the vacuum pump via a switching valve, and the second chamber is connected to the atmosphere, b. In step ii, the switching valve is switched to connect the second chamber to the inlet of the vacuum pump and to connect the inner chamber and the reservoir to the outlet of the vacuum pump.

12. The method according to claim 1, a. in step i, connecting the inner chamber and the reservoir to the inlet of the vacuum pump in series via a first valve, and connecting the second chamber to the atmosphere via a second valve, b. In step ii, the first valve and the second valve are closed, and the inner chamber and the reservoir are connected in series to the outlet of the vacuum pump via a third valve, and the second chamber is connected to the inlet of the vacuum pump via a fourth valve.

13. The method according to claim 1, wherein The breast pump unit comprises an on-off valve, wherein: a. in step i, connecting the inner chamber and the reservoir in series to the inlet of the vacuum pump, and connecting the second chamber to the atmosphere, and b. In step ii, the switching valve is switched to connect the second chamber to the inlet of the vacuum pump and to connect the inner chamber and the reservoir to the outlet of the vacuum pump.

14. The method according to claim 1, wherein The pump assembly comprises a single vacuum pump, wherein: a. in step i, connecting the inner chamber and the reservoir to the inlet of the vacuum pump in series via a first valve, and connecting the second chamber to the atmosphere via a second valve, and b. In step ii, the first valve and the second valve are closed, and the inner chamber and the reservoir are connected in series to the outlet of the vacuum pump via a third valve, and the second chamber is connected to the inlet of the vacuum pump via a fourth valve.

15. The method according to claim 1, wherein The pump assembly includes a pair of vacuum pumps, such that the inner chamber and the reservoir are connected in series to an inlet of a first vacuum pump of the vacuum pumps, and the second chamber is connected to an inlet of a second vacuum pump of the vacuum pumps via a first valve, a pressure line extends between the inlet of the first vacuum pump and an outlet of the second vacuum pump, and the pressure line includes a second valve, the method comprising: a. in step i, opening the first valve to atmosphere and closing the second valve to the fluid passage, operating the first vacuum pump to evacuate the inner chamber and the reservoir to the first vacuum pressure, and b. In step ii, the first valve is closed to the atmosphere, the second valve is opened to the fluid passage, and the second vacuum pump is operated to evacuate the second chamber.

16. A breast pump unit for expressing human breast milk, the breast pump unit comprising: a. a vacuum pump, the vacuum pump is used to generate pressure, b. a reservoir for receiving breast milk, and c. a breast shield for applying in a sealed manner to a breast to be pumped, the breast shield having a flexible inner chamber for receiving a nipple of the breast and a second chamber, the second chamber being an outer chamber extending around the outside of the inner chamber and at least partially surrounding the nipple inserted into the inner chamber, The breast pump unit is operable in a cycle in which: i. the vacuum pump evacuates the inner chamber and the reservoir to a first vacuum pressure, ii. The outer chamber is connected to the vacuum pump and the reservoir so that the outer chamber is evacuated to a second vacuum pressure, wherein, the second vacuum pressure is higher than the first vacuum pressure, and iii. The vacuum in the outer chamber is at least partially released to a lower pressure than the first vacuum pressure.

17. A breast pump unit according to claim 16, the inner chamber being defined by a flexible inner liner comprising an entry portion for receiving a nipple, and the second chamber being defined by a hard or rigid outer liner, the inner liner and the outer liner defining the second chamber therebetween.

18. A breast pump unit according to claim 17, the inner diameter of the access portion being smaller than the outer diameter of the nipple for use with the breast pump unit, and the access portion being expandable when a vacuum is introduced into the inner chamber.

19. A breast pump unit according to claim 16 , the vacuum pump having an inlet and an outlet, and comprising a valve assembly interposed in a pressure line extending from the inlet and the outlet, the valve assembly being operable to switch the inner chamber and the reservoir from a pressure connection with the inlet of the vacuum pump to a pressure connection with the outlet of the vacuum pump, and to switch the outer chamber from a pressure connection with the outlet of the vacuum pump to a pressure connection with the inlet of the vacuum pump.

20. A breast pump unit according to claim 16, comprising a first vacuum pump and a second vacuum pump, wherein An inlet of a first vacuum pump of the vacuum pumps is connected to the reservoir and the inner chamber and an outlet of the first vacuum pump is connected to the atmosphere, and an inlet of a second vacuum pump of the vacuum pumps is connected to the second chamber and an outlet of the second vacuum pump is connected to the atmosphere.

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