The present invention generally relates to apparatuses and methods for sustained medical infusion of fluids, and more particularly to a portable infusion device that can be attached to a patient's body and accurately dispense fluids to the patient's body. Particularly, the present invention relates to an infusion pump that includes two parts: a disposable part and a reusable part. More particularly, the present invention relates to apparatus and methods for monitoring rotation of the infusion pump driving mechanism components.
Medical treatment of several illnesses requires continuous drug infusion into various body compartments, such as subcutaneous and intra-venous injections. Diabetes mellitus patients, for example, require administration of varying amounts of insulin throughout the day to control their blood glucose levels. In recent years, ambulatory portable insulin infusion pumps have emerged as a superior alternative to multiple daily syringe injections of insulin. These pumps, which deliver insulin at a continuous basal rate as well as in bolus volumes, were developed to liberate patients from repeated self-administered injections, and allow them to maintain a near-normal daily routine. Both basal and bolus volumes must be delivered in precise doses, according to individual prescription, since an overdose or under-dose of insulin could be fatal.
Several ambulatory insulin infusion devices are currently available on the market. Mostly, these devices have two portions: a reusable portion that contains a dispenser, a controller and electronics, and a disposable portion that contains a syringe-type reservoir, a needle assembly with a cannula and a penetrating member, and fluid delivery tube. Usually, the patient fills the reservoir with insulin, attaches the needle and the delivery tube to the exit port of the reservoir, and then inserts the reservoir into the pump housing. After purging air out of the reservoir, tube and needle, the patient inserts the needle assembly, penetrating member and cannula, at a selected location on the body, and withdraws the penetrating member. To avoid irritation and infection, the subcutaneous cannula must be replaced and discarded after 2-3 days, together with the empty reservoir. Examples of first generation disposable syringe-type reservoir and tubes were disclosed in U.S. Pat. No. 3,631,847 to Hobbs, U.S. Pat. No. 3,771,694 to Kaminski, U.S. Pat. No. 4,657,486 to Stempfle, and U.S. Pat. No. 4,544,369 to Skakoon. The driving mechanism of these devices is a screw-threaded driven plunger controlling the programmed movement of a syringe piston.
Other dispensing mechanisms have been also discussed, including peristaltic positive displacement pumps, in U.S. Pat. No. 4,498,843 to Schneider and U.S. Pat. No. 4,715,786 to Wolff. These devices represent an improvement over multiple daily injections, but nevertheless, they all suffer from several drawbacks, one of the main drawbacks is its large size and weight of the device, caused by the configuration and the relatively large size of the driving mechanism of the syringe and the piston. This relatively bulky device has to be carried in a patient's pocket or attached to the belt. Consequently, the fluid delivery tube is long, usually longer than 60 cm, in order to permit needle insertion at remote sites of the body. These uncomfortable bulky devices with a long tube are rejected by the majority of diabetic insulin users, since they disturb regular activities, such as sleeping and swimming. Furthermore, the effect of the image projected on a body of a teenager is unacceptable. In addition, the delivery tube excludes some optional remote insertion sites, like buttocks, arms and legs. To avoid the consequences of long delivery tube, a new concept, of second generation pump, was proposed. This concept includes a remote controlled skin adherable device with a housing having a bottom surface adapted to contact patient's skin, a reservoir disposed within the housing, and an injection needle adapted to communicate with the reservoir. These skin adherable devices should be disposed every 2-3 days similarly to available pump infusion sets. These devices were disclosed at least in U.S. Pat. No. 5,957,895 to Sage, U.S. Pat. No. 6,589,229 to Connelly, and U.S. Pat. No. 6,740,059 to Flaherty. Additional configurations of skin adherable pumps were disclosed in U.S. Pat. No. 6,723,072 to Flaherty and U.S. Pat. No. 6,485,461 to Mason. These devices also have several limitations: they are bulky and expensive, their high selling price is due to the high production and accessory costs, and the user must discard the entire device every 2-3 days, including relatively expensive components, such as driving mechanism and other electronics.
e.g., i.e., i.e., i.e., e.g., As mentioned above, the volume of fluid infused to the patient must be delivered in precise doses, according to individual prescription, since an overdose or underdose of insulin could be fatal. The reliability of the infusion pump can be greatly enhanced by monitoring the rotation of the driving mechanism of the infusion pump.
Existing rotation monitoring devices include optic encoders comprising of a large disc mounted on the motor shaft and several sets of light emitting diodes (“LEDs”) and light detectors, as disclosed, for example, in U.S. Pat. No. 6,078,273 to Hutchins. These encoders occupy a large space and hence are not suitable for a miniature infusion pump. Moreover the use of several sets of LEDs and light detectors, which is highly expensive, is not required for the high precision of a stepper motor.
Furthermore, when the encoder is located on the motor shaft it monitors only the rotation of the motor itself, and cannot directly monitor rotations of shafts and gears. Moreover, it does not detect occurrences of electro-mechanical disassociation due to breakage of gears, dust, etc.
Another problem which exists in rotary peristaltic pumps is that the resulting delivery of fluid occurs in a series of pulses or surges, the frequency of which is equal to the frequency of the passage of successive rollers in contact with the delivery tube. This flow pattern is inherent in conventional rotary peristaltic pumps. The effect is that fluid is delivered at a widely varying rate during a pump cycle and this can be unacceptable in infusion procedures in which uniformity of delivery rate is a requirement (e.g., insulin pumps). Moreover, the continuous change in flow rate can cause instability in sensitive feedback control systems which are designed to ensure that fluid is delivered at a constant rate. It was found that during the passage of each peristaltic pump roller in contact with the delivery tube, constant flow was maintained through a portion of the motor cycle, immediately followed by a period of no flow at all in the downstream or positive direction. During this dwell period, there is often some evidence of negative flow.
This means that in normal operation, the pump is delivering no fluid for a portion of its operating time and is delivering fluid at a higher rate than the average for the other cycle portion.
Having frequent periods in which there is no fluid flowing downstream, i.e., towards the patient's body, is extremely hazardous when dealing with therapeutic fluid such as insulin. When an insulin pump is set to its minimal flow rate, it is likely that the patient will not receive any insulin at all.
An example of a control apparatus for the drive motor of a peristaltic pump for maintaining a uniform flow rate is disclosed in, for example, U.S. Pat. No. 4,604,034 to Wheeldon that discusses a control apparatus employing a photo sensor. The control apparatus, however, was not specified as to how it can be materialized, i.e., what the possible locations of the photo sensor are, if it can be employed in a miniature-size infusion pump, etc. Moreover, employment of a different type of sensor other than a photo sensor was not discussed.
i.e., e.g.,
To overcome the deficiencies of the above conventional devices, some embodiments of the present invention are directed to an improved method and device for monitoring the rotation of a driving mechanism (i.e., motor, gears, shafts, etc.) capable of detecting occurrences of electro-mechanical disassociation. In some embodiments, the present invention is directed to an appropriate size (e.g., miniature) device for monitoring the rotation of a driving mechanism. The present invention also provides an efficient and cost-effective device for monitoring the rotation of a driving mechanism.
In some embodiments, the present invention is directed to an appropriately-sized device for monitoring the rotation of a driving mechanism of an infusion pump. The present invention also capable of monitoring the rotation of a driving mechanism of an infusion pump that can be attached to the patient's skin. In some embodiments, the appropriately-sized device for monitoring the rotation of a driving mechanism of an infusion pump includes two parts, e.g., a reusable part and a disposable part. In some embodiments, the device can be attached to and detached from the skin.
In some embodiments, the present invention is directed to an appropriately-sized device for monitoring the rotation of a rotary wheel of a positive displacement peristaltic pump and for providing a solution to the problem of having a no-flow or backflow of fluid as well as minimizing its effects on fluid delivery to the patient.
As can be understood by one skilled in the art, the appropriately-sized term can refer to a miniature size or any other size suitable for the purposes as discussed in the present application.
Some embodiments of the present invention relate to a method and a device for monitoring the rotation of an infusion pump driving mechanism (i.e., motor, gears, shafts, etc.).
In some embodiments, the present invention relates to a self-correction mechanism operating via a feedback control system that accounts for the occurrence of at least one of the following conditions: motor malfunction, electrical wire(s) disconnection, software and/or electronics error(s), battery voltage drop, and/or electro-mechanical disassociation due to breakage of gears, dust, etc.
In some embodiments, the present invention relates to a method and a system for alerting the patient if the above correction attempts fail.
In some embodiments, the present invention relates to a method for preventing or at least minimizing the occurrence(s) of no-flow or backflow in a positive displacement peristaltic pump and minimizing its effects on fluid delivery to the patient.
Some embodiments of the present invention relate to an infusion pump's driving mechanism, which may include DC motor, stepper motor, SMA actuator, etc. It should be noted that in stepper motors, detection of electro-mechanical disassociation is a challenge because motor rotation can be ceased without concomitant voltage or current changes and for the patient it will seem that the motor continues to work properly.
Inefficiency of an infusion pump driving mechanism could be life threatening because of the likely possibility of drug (e.g., insulin) under-dosing. Thus, it would be important to monitor the rotation of an infusion pump's driving mechanism (especially, one employing a stepper motor), and to apply self-correction or alert the patient of incorrect drug delivery in the occurrence of motor malfunction or electro-mechanical disassociation.
Some embodiments of the present invention provide a solution for monitoring the rotation of a miniature infusion pump's driving mechanism in order to ensure that the patient is provided with required amounts of therapeutic fluid.
In some embodiments, the present invention relates to systems and methods for monitoring rotation of the driving mechanism of a miniature infusion pump having two parts: a reusable part and a disposable part, which can be adhered to the skin of the patient and can be attached to and detached from the skin.
Some embodiments of the present invention provide a solution for monitoring the rotation of different components of the infusion pump's driving mechanism so that it is possible to detect occurrences of electro-mechanical disassociation as well as motor malfunction.
Some embodiments of the present invention relate to systems and methods for preventing or at least minimizing the occurrence(s) of backflow in positive displacement peristaltic pumps, and minimizing its effects on fluid delivery to the patient.
Some embodiments of the present invention are directed to a miniature-size, cost-effective rotation monitoring devices, such as one which includes an encoder wheel, at least one light emitting diode (“LED”) and at least one light detector located at opposite sides of the encoder wheel. The device monitors the rotation of at least one component of a driving mechanism (i.e., motor, gear, shaft, etc.), maintains required rotation rate and alerts the user if necessary.
Embodiments of the present invention also relate to a miniature-size, cost-effective rotation monitoring devices, such as one which includes a LED and a light detector located at opposite sides of the rotary wheel, when employing a positive displacement peristaltic pump. The device monitors the rotation of the rotary wheel and increases the motor speed during no-flow or backflow periods of the rotation cycle. For example, when employing a stepper motor, the acceleration is for a predetermined number of pulse trains during the no flow or backflow cycle period.
a-c illustrate exemplary single-part patch unit, two-part patch unit and a remote control unit, according to some embodiments of the present invention.
a-b illustrate an exemplary single-part patch unit (shown in
a is a longitudinal cross-sectional view of the secondary gear when one of its apertures is aligned with the LED and the light detector.
b is a longitudinal cross-sectional view of the secondary gear when none of its apertures are aligned with the LED and the light detector.
a-d are perspective and front views of the secondary gear colored half white and half black and adjacently-situated LED and light detector.
a-e are perspective and side views of an encoder wheel and a photointerruptor.
a-d are front and perspective views of a round disc colored half white and half black and adjacently-situated LED and light detector.
a-d illustrate an exemplary sharpened worm shaft and an adjacently-situated LED and light detector, according to some embodiments of the present invention.
a-c illustrate an exemplary secondary gear with two magnets located either on the gear or within the gear's apertures or depressions, and a “Hall effect sensor”, according to some embodiments of the present invention.
a-d illustrate several exemplary consecutive positions of the rollers of a positive displacement peristaltic pump during the pumping cycle, according to some embodiments of the present invention.
To avoid the price limitation and to extend patient customization, next generation skin adherable dispensing patch unit (“dispensing unit” or “patch unit”) was devised. An example of such device is discussed in a co-pending/co-owned U.S. patent application Ser. No. 11/397,115 and International Patent Application No. PCT/IL06/001276, disclosures of which are incorporated herein by reference in their entireties. This next generation device is a dispensing unit having two parts:
This concept provides possibility for a cost-effective skin adherable infusion device and allows diverse usage of the device, e.g., the use of various reservoir sizes, various needle and cannula types and implementation of versatile operational modes. This generation of infusion pumps allows for various applicable types of pumping mechanisms for the two-part device configuration. The delivery mechanism can be the peristaltic positive displacement pumping mechanism also discussed in co-pending/co-owned U.S. patent application Ser. No. 11/397,115 and International Patent Application No. PCT/IL06/001276.
Alternative driving mechanisms, which can be applied in any one of the various pumping mechanisms, may include DC motor, stepper motor, Shape Memory Alloy (SMA) actuator, etc. An exemplary driving mechanism includes a stepper motor due to its ability to be accurately controlled in an open loop system, i.e., no position feedback is needed, and therefore it is less costly to control.
Stepper motors may be activated discretely by series of sequential input pulses, i.e., “pulse trains”, applied by the central processing unit (CPU), and transmit force and motion (i.e., torque) to the driving mechanism (e.g., “gear trains”).
a-c show an exemplary fluid delivery device having a dispensing unit (10) and a remote control unit (40), according to some embodiments of the present invention. In some embodiments, the dispensing unit (10) can include a single part (as illustrated in
The dispensing unit (10) may employ different dispensing mechanisms, such as a syringe-type reservoir with a propelling plunger, peristaltic positive displacement pumps, or any other suitable dispensing mechanism. The following description will refer to peristaltic positive displacement pumps for illustrative purposes only and is not intended to limit the scope of the present invention. As can be understood by one skilled in the art, other dispensing can be used with the present invention.
a shows an exemplary single-part dispensing unit (10), according to some embodiments of the present invention. The single-part dispensing unit (10) has a single housing in which a peristaltic pump is employed for dispensing fluid to the body of a patient. The unit (10) includes a reservoir (220), a fluid delivery tube (230), a rotary wheel (110), an outlet port (213), a stator (190) elastically supported by a spring (191), a motor (120), electronics (130) (which can include a printed circuit board (“PCB”) and/or other electronic components; throughout the following description, “electronics (130)” and “PCB (130)” will be used interchangeably and refer to the same element), an energy supply means (240), and control buttons (15a) and (15b). The reservoir (220) is in fluid communication with the outlet port (213) via the fluid delivery tube (230). The fluid delivery tube (230) is disposed between the rotary wheel (110) and the stator (190). The fluid delivery tube (230) is squeezed between the stator (190) that is elastically supported by the spring (191) and the rotary wheel (110) during delivery of the fluid via the fluid delivery tube (230). The motor (120) drives rotation of the rotary wheel (110). The energy supply means (240) (e.g., a battery) provides power to the unit (10) and to the motor (120). Electronics (130), which can include a processor, a memory, and other components, are coupled to the motor (120) and control buttons (15), and provide further control of fluid dispensing to the patient. The electronics (130) can also enable communication with the remote control unit (40) (not shown). The electronics (130) can determine the rate of fluid delivery to the patient, e.g., basal rate and/or bolus rate. The buttons (15) control electronics (130), turn the device on/off, and can provide any other desired functions (e.g., programming of the unit (10)). The fluid is delivered from the reservoir (220) through the delivery tube (230) to the outlet port (213).
The rotary wheel (110) includes a rotary gear (not shown), a rotary plate (not shown), and rollers (not shown). Rotation of the rotary wheel (110) and pressing of the rollers against one side of the fluid delivery tube (230), which is being pressed on by the stator (190) on the other side, periodically positively displaces the fluid within the delivery tube (230) by virtue of a peristaltic motion. An example of a suitable positive displacement pump is disclosed in co-pending/co-owned U.S. patent application Ser. No. 11/397,115 and International Patent Application No. PCT/IL06/001276, the disclosures of which are incorporated herein by reference in their entireties. A motor (120), such as a stepper motor, a DC motor, a SMA actuator or the like, rotates the rotary wheel (110) and is controlled by the electronic components schematically designated as electronics (130). As stated above, the electronic components include a controller, a processor and a transceiver. The energy supply means (240) can be one or more batteries. Infusion programming can be carried out by a remote control unit (not shown) or by manual buttons (15) provided on the dispensing unit (10).
b shows an exemplary two-part dispensing unit (10), according to some embodiments of the present invention. The unit (10) has a reusable part (100) and a disposable part (200), wherein each part is contained within its own housing. The reusable part (100) includes a positive displacement pump provided with the rotary wheel (110), the motor (120), the PCB (130) and manual buttons (15). The disposable part (200) includes the reservoir (220), the delivery tube (230), the energy supply means (240), the outlet port (213) and the stator (190).
In this embodiment, fluid dispensing is possible after connecting the reusable part (100) with the disposable part (200). Once the parts are connected, fluid dispensing can be performed in a similar fashion as in the single-part unit (10) shown in
The driving mechanism of the reusable part (100) further includes a source of energy, such radiation, electromagnetic radiation, infrared radiation (“IR”), electrochemical energy, electromechanical energy, mechanical energy, or any other source of energy. In some embodiments, the source of such energy is an LED (112) and an electromagnetic radiation detector (114) that are disposed proximal to the secondary gear (124). In the further description, “source of electromagnetic radiation” will be referred-to as “light source” or as “LED”, and “electromagnetic radiation detector” will be referred-to as “light detector”. The LED (112) and the light detector (114) perform monitoring of the rotation of the secondary gear (124) of the driving mechanism. The LED (112) and the light detector (114) can be configured to be located on the opposite sides of the secondary gear (124), whereby LED (112) emits light toward the light detector (114) and interruption of the light emitted by LED (112) by the secondary gear (124) is detected by the light detector (114). The light detector (114) can be a phototransistor that can detect light emitted by the LED (112). Upon detection of the interruption of the emitted light, a signal is generated and then sent to the processor for processing. Such detection is further discussed below.
As can be understood by one skilled in the art, the LED (112) and the light detector (114) may be located on opposite sides of any rotating component which is a part of the driving mechanism of the dispensing unit (10), for example, the rotary gear (110). In the following description, the arrangement of the LED (112) and the light detector (114) will be discussed for exemplary, illustrative purposes and is not intended to limit the scope of the present invention. As can be understood by one skilled in the art, such arrangement is applicable to any other component in the dispensing unit (10).
As illustrated in
As stated above, to monitor rotation of the secondary gear (124), the secondary gear (124) includes two equally disposed apertures (127) and (127′). The apertures (127) allow the passage of light emitted by the LED (112) through the secondary gear (124) to the light detector (114). As can be understood by one skilled in the art, the LED (112) and the light detector (114) both have appropriate leads which are soldered to the PCB (130) (not shown in
As can be understood by one skilled in the art, there may be only one aperture (127) in the secondary gear (124) or more than two apertures (127) which can be equally spaced, and the apertures (127) may be of any size and shape. In some embodiments, the number of apertures determines the resolution of the monitoring. In the embodiment where the secondary gear (124) includes one aperture, signals transmitted by the light detector (114) indicate only when one full turn of the secondary gear (124) has been completed. In the embodiment, where the secondary gear (124) has two apertures, signals transmitted by the light detector (114) indicate when one-half of a turn of the secondary gear (124) has been completed. In multiple-aperture embodiments, the signals transmitted by the light detector (114) indicate when a part of a turn of the secondary gear (124) has been completed. Rotation of the secondary gear (124) and detection of rotational position of the gear (124) by the light detector (114) determines an amount of fluid to be dispensed through the fluid delivery tube (not shown) to the patient.
As stated above, upon rotation of the secondary gear (124) and alignment of the apertures (127) with the LED (112) and light detector (124), the light emitted by the LED (112) passes through the aperture (127) and is received by the light detector (124). Upon receipt of the emitted light by the light detector (124), the light detector (124) generates a signal that is sent to a processor or CPU (not shown but discussed below with regard to
The motor (120) is coupled to the PCB (130) via electrical leads (125). The leads (125) provide power to the motor (120) from the energy supply means (not shown in
a is a longitudinal cross-sectional view of the secondary gear (124) having two equally disposed apertures (127) and (127′). The secondary gear (124) is rotated by the pinion (122), which is rotated by the motor (120). As illustrated in
As illustrated in
b is another longitudinal cross-sectional view of the secondary gear (124). As shown in
As can be understood by one skilled in the art, the LED (112) can either emit light continuously or, in order to minimize energy consumption, can be activated (either by the CPU (650) or any other component) periodically according to a predetermined time schedule. When using a stepper motor, for example, the LED (112) may be activated by the CPU (650) only when the CPU (650) sends a pulse train to the motor (120). In some embodiments, the present invention can include a DC motor, an SMA actuator, or any other type of motor.
a-d show another exemplary monitoring system of the driving mechanism, according to some embodiments of the present invention. In this embodiment, the secondary gear (124) is colored dichotomously, e.g., half white and half black, as shown in
In this embodiment, the LED (112) either emits light continuously, or, in order to minimize energy consumption, is activated by the CPU (650) periodically according to a predetermined time schedule. When using a stepper motor, for example, the LED (112) may be activated by the CPU (650) when the CPU (650) sends a pulse train to the motor (not shown).
a-b are perspective and side views, respectively, of the encoder vane (116) and the photointerruptor (113) when the vane (116) is located outside the space S between the LED (112) and the light detector (114). In this case, the light (1000) emitted by the LED (112) is detected by the light detector (114). Depending on how the system is set up, upon detection of a no-interruption condition, the light detector (114) does not generate any signals. Alternatively, the light detector (114) can generate a signal indicating no-interruption condition.
c-d are perspective and side views, respectively, of the encoder vane (116) and the photointerruptor (113) when the encoder vane (116) is positioned in the space S between the LED (112) and the light detector (114). In this case, the encoder vane (116) blocks/interrupts the light (1000) emitted by the LED (112). Hence, the light (1000) is reflected from the vane (116) and no light is detected by the light detector (114). Thus, the light detector (114) can generate a signal indicating interruption condition. The reflected light can be collected by a separate light detector (not shown), which can generate the signal indicating interruption condition.
As can be understood by one skilled in the art, the present invention can encompass use of any number of encoder vanes (116) can be coupled to the shaft (128) at different locations. Additionally, the encoder vane (116) can have a plurality of sectors. For example,
The number of sectors determines the resolution of the monitoring, whereas when one sector is used, the signals transmitted by the light detector (114) will indicate whenever a full turn of the secondary gear (124) has been completed, when two sectors are used the signals transmitted by the light detector (114) will indicate whenever half a turn of the secondary gear (124) has been completed, and when four sectors are used the signals transmitted by the light detector (114) will indicate whenever one quarter of a turn of the secondary gear (124) has been completed, etc. As can be understood by one skilled in the art, any number of sectors corresponding to any number of detected turns can be used. Further, monitoring system of the present invention can use any number of light sources/light detectors (e.g., LEDs (112), light detectors (114)) that can be used with the encoder sector(s) 1116. Use of multiple light sources and/or multiple encoder vanes can provide more calibrated monitoring of the rotation motion of the driving mechanism. Such sources/detectors/vanes/sectors can be disposed throughout the driving mechanism.
a-b are front and perspective views, respectively, of another exemplary monitoring mechanism having a dichotomously colored, e.g., half white-colored and half black-colored, round disc (118) affixed to the shaft (128), according to some embodiments of the present invention. The disc (118) rotates with the shaft (128) at the same rotational velocity. The light detector (114) is situated adjacent to the LED (112) and both are facing the disc (118), as shown in
c-d are front and perspective views, respectively, of the disc (118) when the light (1000) emitted by the LED (112) hits the black-colored half of the disc (118). In such a case, the light (1000) is absorbed by the disc, and no light is detected by the light detector (114). In this embodiment, the LED (112) can emit light continuously or, in order to minimize energy consumption, can be activated by the CPU (not shown) periodically based on a predetermined time schedule. When using a stepper motor, for example, the LED (112) may be activated by the CPU only when the CPU sends a pulse train to the motor (120). As can be understood by one skilled in the art, similar to the encoder vanes (116), the disc (118) can have multiple “white-colored” and “black-colored” portions. Further, the monitoring system of the present invention can have a multiple number of discs (118) located throughout the system for additional monitoring of the rotational motion of the driving mechanism. As can be understood by one skilled in the art, the designations of “white-colored” and “black-colored” are provided for purely illustrative and non-limiting purposes.
a shows another exemplary rotation monitoring system of the driving mechanism, according to some embodiments of the present invention. In this embodiment, the distal end of the shaft (128) is configured to have a flat portion (111) and a semi-circular portion (119). As the shaft (128) is circular, in some embodiment, a half of the cylindrical portion can be cut away from the distal tip of the shaft (128) to create the flat portion (111), as shown in
c-d show the light (1000) hitting the semi-circular side (119) of the shaft (128). In such a case, the light (1000) reflected from the shaft (128) is scattered in different directions, such that only a very small portion of the light can be collected by the light detector (114). Even though such minimal amount of light is collected by the light detector (114) and the light detector (114) may produce a signal indicating such detection, which is transmitted to the CPU (not shown). The CPU can distinguish between the signals produced as a result of the emitted light hitting the flat side (111) and the semi-circular side (119) of the distal end of the shaft (128). As can be understood by one skilled in the art, there can be a multiple number of sides (111) (thereby creating a plurality of partially-circular sides (119)). As stated above, the monitoring system can include a plurality of LEDs and light detectors.
a-c show an alternate exemplary monitoring system of the driving mechanism that is based on the “Hall Effect” principle, according to some embodiments of the present invention. The Hall Effect relates to the formation of a difference in potential between opposite sides of an element composed of a conducting or a semi-conducting material through which an electric current is flowing, whereby a magnetic field is applied perpendicularly to the electric current. As shown in
b illustrates the situation when one of the magnets (92) located on the secondary gear (124) passes vis-à-vis the “Hall effect sensor” (90) and exposes the sensor (90) to its maximum magnetic field. As a result, the electrical signal transmitted by the “Hall effect sensor” (90) either to the CPU (not shown) or to another electronic component, e.g., a comparator (not shown), peaks. The “1” marked on the “Hall effect sensor” (90) in
c shows a situation when none of the magnets (92) are located vis-à-vis the “Hall effect sensor” (90). In this case, the electrical signal transmitted by the “Hall effect sensor” (90) either to the CPU (not shown) or to another electronic component, e.g., a comparator (not shown), remains constant. The “0” marked on the “Hall effect sensor” (90) in
The reusable part (100) has the PCB (130), the manual buttons (15), the driving mechanism having the pinion (122), the secondary gear (124), the worm (126), the shaft (128), a gear wheel (134), and a restraining component (132). After connection of the reusable part (100) and disposable part (200), fluid dispensing can be possible. The motor (120) rotates the pinion (122), which is coupled to the secondary gear (124). The teeth of the pinion (122) are meshed with the teeth of the secondary gear (124), so that the teeth of the pinion (122) transmit torque to the teeth of the secondary gear (124) which then rotates in the opposite direction. The secondary gear (124) and the worm (126) are both mounted on one shaft (128), so that they rotate at the same velocity, as discussed above with regard to
The rotation monitoring device (1608) monitors rotation of at least one component of the driving mechanism (i.e., motor, gear, shaft, etc.) and transmits a signal produced by the light detector or any other sensor to the CPU (1602) (or to another electronic component, e.g., a comparator (not shown), which is connected to the CPU). The CPU (1602) then processes the signal received from the monitoring device and derives from it the number of revolutions executed by the motor during a predetermined time period, or during the dispensing of a predetermined amount of therapeutic fluid, etc. The CPU (1602) computes the number of revolutions which should have been executed by the motor according to pre-programmed data regarding the amount of therapeutic fluid dispensed in the course of one motor revolution and data inputted by the patient regarding the amount of therapeutic fluid to be infused. The CPU compares the actual number of executed revolutions with the number of revolutions which should have been executed by the motor, and if they are dissimilar, i.e., if the motor has executed fewer revolutions than necessary, or more than necessary, the CPU will execute the needed correction of the revolution of the driving mechanism. For example, if the information derived from the signal transmitted by the monitoring device indicates that the motor has executed X rotations in a specific time period, whereas it should have executed Y rotations in the said period of time, the CPU will send a command to the motor to rotate an extra Z rotations during the following predetermined time period, whereas Z=Y−X. If correction attempts fail, the CPU will alert the patient via an alerting component located in the reusable part of the infusion pump and\or the remote control unit. The above mentioned monitoring devices can also provide a solution to the backflow problem which is inherent in rotary peristaltic pumps.
a-d show several consecutive positions of the rollers, as shown in
As can be understood by one skilled in the art, the same effect can be achieved by placing said apertures (127), (127′) (only two apertures are shown) closer to the center of the rotary gear plate (106) and disposing four appropriate apertures on the rotary plate (109), so that every two corresponding apertures are aligned. In this case the LED (112) is located on the outer side of the rotary gear plate (106) and the light detector (114) is located on the outer side of the rotary plate (109), or vice versa, and in order for the light emitted by the LED (112) to be collected by the light detector (114), a pair of apertures (one on the rotary gear plate (106) and one on the rotary plate (109)) has to be aligned with the LED (112) and the light detector (114).
The light detector (114) and the LED (112) used may be two separately located components, as illustrated, or fixed adjacently on a common support frame made of an opaque-material package, e.g., a photointerruptor. As can be understood by one skilled in the art, a monitoring device based on the “Hall effect”, employing magnets and a “Hall effect sensor”, as shown in
The closed loop system for executing a feedback process for the purpose of minimizing the occurrence of no flow or backflow and its effects on fluid delivery to the patient is similar to the one shown in
The monitoring device monitors rotation of the rotary wheel and transmits an electronic signal produced by the light detector or other sensor to the CPU (or to another electronic component which is connected to the CPU). The CPU adjusts rotation speed according to the relative position of the rollers and the tube. In case of a stepper motor acceleration is achieved by continuously sending pulse trains to the motor. Acceleration of the rollers motion during no flow or backflow periods maintains a uniform flow rate. In an alternative embodiment, when a stepper motor is employed the CPU can be programmed to disregard the pulse trains resulting in no-flow or backflow due to the position of the rollers, and not count them in the calculation of total delivered fluid. In some embodiments, when stepper motor is employed the CPU can adjust the rotation speed according to the relative position of the rollers and the tube, and in addition be programmed to disregard these pulse trains and not count them in the calculation of total delivered fluid.
Example embodiments of the methods and components of the present invention have been described herein. As noted elsewhere, these example embodiments have been described for illustrative purposes only, and are not limiting. Other embodiments are possible and are covered by the invention. Such embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
The present application claims priority to U.S. Provisional Patent Application No. 60/928,751, filed May 11, 2007 and incorporates disclosure of this application herein by reference in its entirety. The present application also claims priority to U.S. Provisional Patent Application No. 60/928,815, filed on May 11, 2007, and entitled “A Positive Displacement Pump”, and U.S. Provisional Patent Application No. 60/928,750, filed on May 11, 2007, and entitled “Fluid Delivery Device”. This application incorporates disclosures of each of these applications herein by reference in their entireties. The present application also relates to the co-owned/co-pending U.S. patent application Ser. No. ______, and International Patent Application No. PCT/IL08/______, both filed on the even date herewith, and both entitled “A Positive Displacement Pump”, and U.S. patent application Ser. No. ______, and International Patent Application No. PCT/IL08/______, both filed on the even date herewith, and both entitled “Fluid Delivery Device”. The disclosures of these applications are incorporated herein by reference in their entireties.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IL2008/000642 | 5/11/2008 | WO | 00 | 11/12/2009 |
Number | Date | Country | |
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60928751 | May 2007 | US | |
60928815 | May 2007 | US | |
60928750 | May 2007 | US |