JP4617356B2 - Combined flow, bubble, and occlusion detector - Google Patents

Description

  The present invention relates to a flow sensor device for obtaining flow characteristics of a fluid flow system, such as a system used to administer a beneficial agent to a patient. In particular, the present invention is directed to a flow measurement device comprising first and second pressure sensors in a flow path for measuring beneficial drug flow and optionally measuring the presence of air in a fluid flow system. It has been. Furthermore, the present invention encompasses related systems and methods for obtaining such flow characteristics.

  If a given amount of beneficial agent is administered to a patient in liquid form over a long period of time, it may not be necessary to obtain and monitor relevant flow characteristics such as flow rate and the presence of air. Useful. Although methods for obtaining such information have existed for many years, so far, no reliable low-cost system for disposable use has been developed.

  For example, measurement of fluid flow in a disposable IV fluid line or similar supply set has generally not been economically and technically feasible to date. Low cost electronic flow sensors have been around for some time, but no feasible alternative has been presented so far to solve this problem. Preventing the commercialization of such devices includes the poor dynamic range of low cost flow sensor systems and the unacceptable cost of the entire sensor assembly.

  One problem in the low cost manufacturing of flow sensors is in the manufacturing process. Typically, a silicon chip is wire bonded to a lead frame, sealed and soldered to a printed circuit board. This configuration requires a manual process of welding the wires from the chip to the lead frame, which can cause significant additional manufacturing costs.

  Similarly, in the medical field, an economical and reliable system for detecting the presence of air in an IV line or other medical supply set has been needed for many years. Typically, the presence of air in the fluid line is detected from outside the fluid path using separate ultrasonic or optical sensors, but these sensors are used to form disposable piping or fluid paths. You must communicate through the parts. Ultrasound techniques can be subject to misalignment and other geometrical changes, including the conduction of signals to and around the fluid inside the pipes or other components of the disposable fluid path. It can affect the conduction of signals through the fluid. Optical techniques require the formation of a unique geometry in the fluid path that becomes reflective or conductive in response to the presence of air or liquid. These systems are subject to the variability of the disposable fluid pathway and interact with the disposable fluid pathway. Furthermore, the additional cost of these air detection systems has hindered widespread adoption.

  Thus, a need exists in the art for a sufficiently inexpensive and reliable fluid flow detection system that can be used in disposable applications. There also continues to be a need for inexpensive and reliable systems for detecting the presence of air in fluid systems such as IV lines and supply sets.

  Objects and advantages of the present invention will become apparent from the following description and will be apparent from the practice of the invention. Additional advantages of the present invention will be realized and obtained by the methods and systems particularly pointed out in the written description and claims as well as from the appended drawings.

  To achieve these and other advantages, in accordance with the purpose of the present invention, as embodied and broadly described, the present invention is directed to an apparatus for obtaining flow characteristics of a fluid flow system. Yes.

  The device includes a sensor assembly. The sensor assembly includes a body defining a first fluid flow path having an inlet and an outlet, and a flow restricting element positioned along the first fluid flow path between the inlet and the outlet. An upstream fluid pressure sensor is provided for detecting upstream fluid pressure at an upstream position of the first fluid flow path between the inlet and the flow restricting element. The sensor assembly further includes a downstream fluid pressure sensor for detecting downstream fluid pressure at a location downstream of the first fluid flow path between the flow restriction element and the outlet. The sensor assembly also includes an upstream signal contact connected to the upstream fluid pressure sensor and a downstream signal contact connected to the downstream fluid pressure sensor.

  The device further includes a housing. The housing has an upstream portion and a downstream portion. An upstream portion of the housing defines an upstream port in fluid communication with the inlet of the sensor assembly. A downstream portion of the housing defines a downstream port in fluid communication with the outlet of the sensor assembly. The housing further defines a probe access port configured to provide probe access to at least one of the upstream signal contact and the downstream signal contact.

  According to a further aspect of the invention, the housing has at least one positioning surface configured to ensure proper positioning of the device and the fluid flow system. The positioning surface ensures that the upstream port is aligned with the fluid source. The positioning surface may include a configuration of the surface of the upstream portion of the housing that is different from the configuration of the surface of the downstream portion of the housing. According to one aspect of the invention, the positioning surface includes at least one flat surface. Further, the positioning surface may comprise a detent.

  According to a further aspect of the invention, the housing defines a cavity of a predetermined shape, and the sensor assembly has a corresponding shape to be received into the cavity. The cavity may have at least one surface that may include at least one recess for receiving material for holding the sensor assembly within the cavity. Furthermore, a cap can be placed in the cavity proximate to the sensor assembly. The housing may have a connector, such as a Luer connector or a flange, in the vicinity of at least one of the upstream port and the downstream port for connection to the fluid flow system.

  According to another aspect of the present invention, the housing can define a second fluid flow path therethrough. The second fluid flow path can be arranged in fluid communication between the upstream port and the downstream port in parallel with the first fluid flow path. Furthermore, a valve can be provided for selective flow through the second fluid flow path. For example, the valve can be formed as a compressible wall member that defines at least a portion of the second fluid flow path. The compressible wall member can be formed from an elastic material. In a preferred embodiment, the second fluid flow path has a first transverse dimension and a second transverse dimension that is orthogonal to the first transverse dimension. Preferably, the first dimension is smaller than the second dimension so that it can be more easily compressed. Preferably, the cross section of the second fluid channel has an elliptical shape with a small radius at each vertex to facilitate compression of the second fluid channel.

  According to another aspect of the invention, a fluid sensor system is provided. The system includes a device for obtaining the flow measurement described above, as well as a probe for receiving a signal representative of fluid flow characteristics, and a processor for processing such a signal. The probe can include a connector body having a predetermined shape, such as a wedge configuration, and the probe access port is adapted to ensure that the probe is properly aligned with at least one of the upstream signal contact and the downstream signal contact. It has a shape to The probe further includes a plurality of leads. At least one lead is provided for communication with the upstream signal contact and at least one lead is provided for communication with the downstream signal contact. At least one lead on the probe is configured to wipe at least one of the upstream signal contact and the downstream signal contact. Preferably, the housing provides contact at one longitudinal surface and one vertical surface of the housing to ensure contact between the leads on the probe and the upstream and downstream signal contacts. Is configured to provide the appropriate force for. The signal contacts may be located proximate to the positioning surface on the outside of the housing that engages the external clamp assembly (also referenced to the probe).

  According to a further aspect of the invention, the system further comprises a fluid flow line in communication with the fluid source. Preferably a locking mechanism is provided for combining the housing with the fluid flow line. The locking mechanism has an unlocked state for receiving the housing, a first locked state for aligning the housing with the fluid flow line, and a second locked state for positioning the probe within the housing. is doing. Further, as described above, if the housing is defined with a second fluid flow path with a valve, the system further includes a locking mechanism from the first locked state to the second locked state. And an actuator for changing the valve from the first state to the second state. The actuator can include a protrusion for compressing the elastic wall member. In one embodiment of the present invention, the protrusion is a pin.

  Further in accordance with the present invention, the fluid source comprises a pump connected to the fluid flow system for selectively delivering fluid through the first fluid flow path. A processor is configured to control the pump in response to a signal obtained from the sensor by the probe.

  Further in accordance with the present invention, a method for obtaining a flow measurement is provided. The method includes providing a device for obtaining a flow rate measurement as described above, directing a fluid flow through the first fluid flow path, a first fluid pressure sensor, and a first fluid pressure sensor at a location of the downstream fluid pressure sensor. Obtaining a signal corresponding to the pressure of the fluid in the fluid flow path, and determining a flow characteristic based on the signal.

  According to a further aspect of the invention, the determining step includes determining a pressure difference between the upstream fluid pressure sensor and the downstream fluid pressure sensor. The determining step can further include calculating a flow rate of the fluid passing through the first fluid flow path based on the pressure difference.

  According to another aspect of the invention, the determining step includes detecting the presence of air in the first fluid flow path. Detecting air in the first fluid flow path may include identifying convergence and characteristic waveforms of signals received from the upstream fluid pressure sensor and signals received from the downstream fluid pressure sensor. it can.

  According to yet another aspect of the present invention, the step of delivering fluid in intermittent pulses through the first fluid flow path, and using the upstream fluid pressure sensor and the downstream fluid pressure sensor, A method is provided that further includes determining the amount of fluid delivered by each pulse by detecting the pressure of the fluid in one fluid flow path.

  According to yet another aspect of the present invention, there is provided a method wherein a housing provided in a housing process comprises a second fluid flow path and a valve for selecting a flow through the second fluid flow path. The The valve has a first state that allows flow to pass through the second flow path and a second state that prevents flow from passing through the second flow path. The method further includes opening the valve to increase flow through the housing.

  Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. The method and corresponding steps of the present invention will be described in connection with a detailed description of the apparatus. The methods and apparatus presented herein are used to obtain flow characteristics of a fluid flow system, such as flow measurement. The present invention is particularly suitable for the administration of a beneficial agent to a patient, particularly when a steady amount of beneficial agent is measured over a long period of time (eg, several days). According to the present invention, it is possible and desirable to provide an apparatus for obtaining such measurement values, which is inexpensive to manufacture and easy to use. The present invention can be used particularly advantageously in intravenous (IV) applications or similar supply sets where a flow system comprising a reservoir and a supply tube is intended to be disposable after use.

  For purposes of explanation and illustration only, and not as a limitation of the invention, an exemplary embodiment of an apparatus for obtaining flow characteristics according to the invention is shown in FIGS. Reference numeral 100 indicates. This exemplary embodiment is also depicted in FIGS. 2a-6. Further embodiments are shown in FIGS. 7a to 8h and FIGS. 11a to 12 for purposes of illustration and not limitation.

  For example, for purposes of introduction only, FIGS. 1a-6 show a flow sensor device 100 for obtaining flow characteristics according to the present invention. 9-10 illustrate a sensor assembly 40 that includes a flow restriction element 50, an upstream fluid pressure sensor 52, and a downstream fluid pressure sensor 56. FIGS. 1 a-3 show one embodiment of a housing 10 for the sensor assembly 40 of the device. Other embodiments or variations of this device as shown in FIGS. 7a to 8h are also suitable for the present invention, as will be understood from the following description.

  The flow sensor device according to the present invention includes a sensor assembly. The sensor assembly generally includes a first fluid flow path having an upstream pressure sensor and a downstream pressure sensor separated by a flow restriction element.

  For purposes of illustration and not limitation, the sensor assembly 40 is schematically depicted in FIGS. 9-10. 9 shows a side view of the sensor assembly 40, while FIG. 10 shows a perspective view of the sensor assembly 40. The sensor assembly 40 includes a body 42 that defines a first fluid flow path 44, which includes an inlet 46, an outlet 48, and an inlet 46 along the first fluid flow path 44. And a flow restricting element 50 located between the outlet 48 and the outlet 48. As shown in FIG. 10, positioning extension 43 provides positioning between housing 10 and sensor assembly 40 as described below (FIGS. 5a-5b, 7d-7e, 8d). See also). As embodied herein, the sensor assembly 40 further detects upstream fluid pressure at an upstream location 54 in the first fluid flow path 44 between the inlet 46 and the flow restricting element 50. An upstream fluid pressure sensor 52. The sensor assembly 40 further includes a downstream fluid pressure sensor 56 for detecting downstream fluid pressure at a downstream location 58 in the first fluid flow path 44 between the flow restriction element 50 and the outlet 48. . At least one upstream signal contact 60 is connected to the upstream fluid pressure sensor 52 and at least one downstream signal contact 62 is connected to the downstream fluid pressure sensor 56. Preferably, the signal contacts 60, 62 are located in the positioning extension 43 for easy access, as will be described later.

  According to one aspect of the present invention, the sensor assembly can be configured as an independent component such that the body is configured by one or more walls as shown in FIG. As embodied herein, the upstream pressure sensor 52 and the downstream pressure sensor 56 are preferably formed on the first inner surface 64 of the first wall 66 of the body 42. The first inner surface 64 is substantially flat. The device further includes a second inner surface 68 of the second wall 70, which is also substantially flat as embodied herein. As embodied herein, a third wall 72 and a fourth wall 74 are further provided to separate the first wall 66 and the second wall 70. The first wall 66, the second wall 70, the third wall 72, and the fourth wall 74 of the sensor assembly 40 together cooperate to define a first fluid flow path 44 therebetween. Work. The first wall 66 and the second wall 70 are preferably formed of glass or a similar suitable substrate. The third wall 72 and the fourth wall 74 are preferably made from silicon or the like, and are first photolithographically deposited and / or using chemical etching or ion bombardment techniques as known to those skilled in the art. Wall 66 and / or second wall 70. The upstream pressure sensor 52 and the downstream pressure sensor 56 of the preferred embodiment are, for example, capacitive pressure sensors as disclosed in US Pat. No. 6,445,053 entitled “Micro-Machine Absolute Pressure Sensor”. The disclosure of which is expressly incorporated herein by reference. This type of pressure sensor is used in the flow measurement device disclosed in US Pat. No. 6,349,740 entitled “Monolithic High-Performance Miniature Flow Control Unit”. Is expressly incorporated herein by reference.

  According to another embodiment (not shown) of the present invention, the upstream pressure sensor 52 and the downstream pressure sensor 56 are not necessarily located in the first flow path 44. For example, pressure sensors 52, 56 are located outside the first fluid flow path 44 and are in fluid communication with the upstream position 54 and the downstream position 58, such as by pressure taps and / or fluid lines (not shown). May be. In further accordance with this alternative embodiment of the present invention, the body may be formed as part of the housing to define the first flow path 44 with the flow restricting element 50. In this manner, as described below, the body of the sensor assembly can be formed during the insert molding process rather than providing separate components.

  Various alternative configurations and structures can be used for the upstream pressure sensor 52 and the downstream pressure sensor 56. Although a capacitive pressure sensor is depicted here, other types of differential pressure measurements can be used. This is particularly applicable when the pressure sensors 52, 56 are not inside the fluid flow path 44. In accordance with this alternative aspect of the present invention, the measurement of the pressure difference between the upstream position 54 and the downstream position 58 can be accomplished in any one of a number of ways.

  For example, when a pressure tap (not shown) is connected to a pressure transmission line (not shown) and provided at the upstream position 54 and the downstream position 58, the respective pressure transmission lines are connected to both ends of the differential pressure measuring device. It is possible to connect to. An example of such an apparatus is a liquid-filled pressure gauge. Alternatively, a diaphragm in which one or more conductive elements are arranged can be used to detect the differential pressure. According to this aspect of the present invention, each of the upstream pressure sensor 52 and the downstream pressure sensor 56 can be considered to be each of the two inputs of the differential pressure measuring device.

  As already mentioned, according to the invention, the flow restricting element is located between the inlet and the outlet along the first fluid flow path. With reference to FIGS. 9-10, the flow restricting element 50 is formed on the first inner surface 64 and / or the second inner surface 68. The flow restricting element 50 is sufficient to provide a proportionally greater pressure drop in fluid passing through the first fluid flow path 44 over a relatively short distance compared to a flow path without such a flow restricting element. Are dimensioned and shaped. In this preferred embodiment, flow restricting element 50 is preferably formed by depositing a semiconductor material, such as silicon, onto first inner surface 64 and / or second inner surface 68. The flow restricting element 50 can be formed integrally with the first wall 66 and / or the second wall 70 or can be formed separately as an insert. Similarly, the flow restricting element 50 can be provided with a variety of alternative configurations, such as an orifice extending through the wall.

  Various configurations for the structure of the sensor assembly 40 can be used. For example, the pressure sensors 52, 56 can be provided on a glass substrate, which can then be placed into a first fluid flow path generally molded within the housing. Alternatively, as already described, the first fluid flow path 44 can be molded into the housing 10 having a line in fluid communication with the pressure taps and pressure sensors 52, 56. In this alternative embodiment of the present invention, the first fluid flow path 44 can be provided in a cylindrical shape. Similarly, the flow restricting element 50 may be provided in the form of an orifice disposed within the first fluid flow path 44 or formed integrally with the first fluid flow path 44. The sensor assembly 40 may be a monolithic sensor assembly having the flow restriction element 50 and the pressure sensors 52, 56 in an integrated structure. A monolithic sensor assembly can reduce assembly cost and size of the sensor assembly.

  In accordance with the present invention, the flow sensor device further includes a housing for the sensor assembly. The housing is configured to contain and protect the sensor assembly and to ensure proper installation in the fluid flow system.

  While not intending to limit the invention, for example, FIGS. 1 a-1 c depict a housing 10 embodied herein. The housing 10 has a central portion 12 in which the sensor assembly 40 is accommodated. The housing 10 defines an upstream port 14 located at the upstream end 16 of the housing 10 and a downstream port 18 located at the downstream end 20 of the housing 10.

  Further, as embodied herein, the housing 10 further comprises an upstream portion 26 and a downstream portion 28. As depicted herein, according to the present invention, the upstream portion 26 defines the upstream port 14 and the downstream portion 28 defines the downstream port 18. Any of a variety of suitable configurations can be used, but the ports embodied herein each taper to a narrow rectangular cross-section proximate the central portion 12 to provide upstream flow path 27 and Cylindrical holes each defining a downstream flow path 29 are included.

  In a preferred embodiment of the present invention, the upstream connector 15 is located close to the upstream port 14 and the downstream connector 19 is located close to the downstream port 18. Each connector can be provided as a flange that mates with a corresponding flange of the fluid flow system, although other connector embodiments can be envisaged if desired. For example, it is possible to use in particular Luer connectors, screw-type connections or mating connectors. The geometry of the housing 10 and connectors 15, 19 are configured to provide a suitable seal to prevent leakage of liquid or gaseous fluid.

  Further in accordance with the present invention, the housing is provided with at least one positioning surface configured to ensure proper positioning of the flow sensor device in the fluid flow system. In particular, ensuring that the inlet to the sensor assembly is positioned upstream of the fluid flow system (ie, the fluid source), while the outlet of the sensor assembly is positioned downstream of the fluid flow system. It is beneficial.

  For purposes of illustration and not limitation of the present invention, one or more positioning surfaces are provided in each of the upstream engagement portion 22 and the downstream engagement portion 24, as illustrated herein in FIG. 1a. 30 is provided. The positioning surface 30 is configured to provide alignment between the housing 10 and the fluid flow system, as depicted in FIG. When the device 100 is used, the positioning surface 30 ensures that the upstream port 14 is properly aligned with the fluid source. As depicted in FIG. 1a, each of the positioning surfaces 30 can be provided as a flat surface that is clearly tilted to mate with a corresponding flat surface, or is shown in FIG. 7b provided in a fluid flow system. Can be provided as any of a number of other configurations, such as protrusions, keys, or detents. The positioning surface 30 can be provided anywhere on the surface of the housing 10. For example, if the shape or position is asymmetric, only one positioning surface can be provided. If positioning surfaces 30 are provided at both the upstream and downstream positions of the housing 10, the shape of each positioning surface 30 is different so that the device 100 is not installed upside down on the flow system. It will be.

  According to one aspect of the invention, as depicted in FIGS. 1b, 1a, and 2b, the central portion 12 of the housing 10 defines a cavity 32 of a predetermined shape. As embodied herein, the present invention is not limited and for purposes of illustration, the cavity 32 is rectangular in shape. The sensor assembly 40 has a shape and size corresponding to the shape and size of the cavity 32, as will be described in detail later. In this manner, the housing can be fabricated separately from the sensor assembly and later installed if desired. In addition, the cavity and sensor assembly can be provided with a corresponding asymmetric shape to ensure only one direction between the two components. The sensor assembly can be held in the cavity by various mechanisms, such as a mating configuration or similar mechanical connection. As a preferred embodiment, it is possible to use adhesives, binders or welding materials. The cavity 32 can preferably have at least one surface 34 provided with one or more recesses 36. As depicted in FIG. 6, the recess 36 is dimensioned to receive a predetermined amount of such material, such as an adhesive, to hold the sensor assembly 40 in the cavity 32.

  For purposes of illustration and not limitation, the cavity 32 is further configured to accommodate a cap 38, as embodied herein in FIGS. 1a and 4a-4d. The cap 38 also has a shape and size corresponding to the shape and size of the cavity 32. The cap 38 has an upper surface 38a, a lower surface 38b, an end wall 38c, and a side wall portion 38d. The cap 38 is placed into the cavity 32 after the sensor assembly 40 is inserted, with the lower surface 38b adjacent to the sensor assembly 40. Alternatively, the sensor assembly 40 may be first attached to the lower surface 38b of the cap 38 and then installed into the cavity 32. As can be seen in FIG. 1 a, the cap 38 has a profile similar to that of the housing 10 when fully inserted into the cavity 32.

  According to yet another aspect of the invention, the cavity and cap can be used in combination to define the first fluid flow path of the sensor assembly. For example, the upstream fluid pressure sensor 52 and the downstream fluid pressure sensor 56 can be attached to a suitable substrate, such as glass, disposed in the cavity. While defining the side walls of the first fluid flow path 44 with the side walls of the cavity, a cap is placed within the cavity at an appropriate distance from the sensors 52, 56 to complete the fluid flow path 44. If desired, the flow restricting element can be formed on the lower surface 38b of the cap or can be provided as a separate element.

  The housing 10 is preferably made of plastic that is injection molded inside the molding cavity. In particular, the housing can be made from acrylic, cryolite, or composite fiber reinforced material, although any other suitable material such as metals and ceramics can be used. If plastic is used, the housing 10 is preferably formed by liquid injection insert molding. As is known in the art, insert molding for hollow members generally causes liquid plastic material to flow to a preselected volume within the cavity to define voids in the finished article. Use of a removable insert within the molding cavity to prevent the occurrence of However, it will be understood that other techniques such as cutting or machining may be used if desired.

  For example, the advantage of the housing 10 shown in FIG. 1a is that it can generally be made by injecting plastic material into the mold only once. In this manner, inserts or “slides” are provided in the molding cavity to define the voids to be created for the cavity 32, the upstream channel 27, and the downstream channel 29. A liquid plastic material is then poured into the mold to fill all open spaces. After curing, the slide is removed and the housing 10 is removed from the mold. The net result is a housing 10 as depicted in FIG. The cavity 32 provided in this first exemplary embodiment of the housing 10 allows for the installation of the sensor assembly 40 in the housing 10 as described above and is subsequently shown in FIG. 1a. Installation of the cap 38 is continued. The cap 38 is also preferably made from an injection molded plastic material such as cryolite or acrylic, but can also be made from other plastic materials, composite materials, or metals if desired.

  Further in accordance with the present invention, the housing defines a probe access port configured to provide probe access to at least one of the upstream signal contact and the downstream signal contact.

  For purposes of illustration and not limitation of the present invention, and with particular reference to FIGS. 1a, 3, 5a, 5b, and 14a, 14b, as embodied herein, probe access port 39 Is defined by a gap between the cap 38 and the sensor assembly 40. Probe access port 39 provides access of probe 90 to at least one of upstream signal contact 60 or downstream signal contact 62 on surface 43, preferably both. The physical geometry of the probe access port 39 provides alignment between the signal contacts 60, 62 and the external probe 90 as described below. In general, however, the probe access port 39 may be of any desired configuration that provides proper positioning between the signal contacts 60, 62 and the probe 90.

  In particular, according to another aspect of the invention, the probe access port 39 is shaped and dimensioned to correspond to a predetermined shape and dimension of the probe to ensure that the probe is properly aligned with the corresponding contact 60,62. have. As a preferred embodiment, a wedge shape is used as the predetermined shape of the connector body of the probe 90 and the corresponding port 39. The contacts 60, 62 are located at the wedge-shaped apex of the adjacent port 39, and the lead 92 of the probe 90 is located at the apex of the connector body. In this manner, the wedge-shaped oblique surfaces interact to more accurately align the lead 92 to the contacts 60, 62, as shown in FIGS. 14a, 14b. In this way, contact is formed between the probe 90 and one longitudinal surface 39a and one radial surface 39b that define the probe access port 39 in the housing 10 and lead 92 on the probe 90 is formed. And a suitable force to ensure contact between the contacts 60, 62 on the sensor assembly 40. These electrical contacts are preferably in close proximity to the positioning surface 30 on the outside of the housing 10, and an external clamp assembly 120, preferably also referenced to the probe 90, engages the positioning surface 30 ( See FIGS. 15a to 15c).

  A wide variety of configurations can be used for the probe access port 39. Alternatively, the port 39 may be slotted or take other forms as long as the geometry of the housing 10 provides positioning and alignment between the signal contacts 60, 62 and the lead 92 of the probe 90. .

  In accordance with another aspect of the present invention, the housing can further define a second fluid flow path between the upstream port and the downstream port of the device.

  For purposes of illustration and not limitation, FIGS. 7a-7e and 8a-8h show a second exemplary embodiment of a flow measuring device according to the present invention. As embodied herein, the housing 10 includes a second fluid flow path 80. The second fluid flow path 80 provides a flow path arranged for fluid communication in parallel with the first fluid flow path 44 between the upstream port 14 and the downstream port 18. In this manner, the second fluid flow path can function as a bypass line combined with the first fluid flow path. This embodiment is particularly beneficial when more fluid flow must flow through the flow restricting element of the sensor assembly.

  Preferably, a valve is provided in operative communication with the second fluid flow path for selectively flowing fluid through the second fluid flow path. Any of a variety of suitable valve configurations can be provided. However, in a preferred embodiment, the valve is formed with a compressible wall member 82 of the second fluid flow path 80, as shown in FIGS. 8a-8h. The compressible wall member 82 is preferably formed from an elastic material such as silicone.

  Further, the second fluid flow path 80 has a first transverse dimension 84 and a second transverse dimension 86 that is orthogonal to the first transverse dimension (see FIG. 8e). As embodied herein, the first transverse dimension 84 is smaller than the second transverse dimension 86, so the cross section of the second fluid flow path has an elliptical shape with a small radius at each vertex 87. (See FIGS. 8d, 8e, and 8h). In this manner, compressible wall member 82 is more easily compressed by applying a force in the direction of the first transverse dimension than if the second fluid flow path has a circular cross-section. be able to. Furthermore, the small radius of each vertex 87 ensures that the second fluid flow path can be closed by applying minimal force.

  Note that a modified manufacturing process is used when forming the device according to the second exemplary embodiment of the present invention of FIGS. 7a to 7e and 8a to 8h. When forming the housing 10 with the compressible wall member 82, the housing 10 is formed in a separate manufacturing process.

  In order to fabricate the embodiment of the housing 10 shown in FIGS. 7a-7e, 8a-8h, 11a-11b, and 12, preferably the sensor assembly 40 is first moved between the slides in the mold. Disposed where the slide defines a void to be created for the second fluid flow path 80 and the surrounding resilient wall member 82, the upstream flow path 27, the downstream flow path 29, and the probe access port 39. To do. The desired liquid plastic material is then poured into the mold and fills all open spaces as described above. After curing, the housing has a configuration as shown in FIGS. 7a to 7e. The slide that defines the gap to be created for the second fluid channel 80 and the surrounding elastic wall member 82 is replaced with a smaller slide that corresponds to the size and shape of the second fluid channel 80. As embodied herein, an elliptical cross-section elongated slide having a small radius at the apex 87 can be used. The slide that defines the upstream flow path 27 and the downstream flow path 29 is also slightly pulled to create a disk-shaped gap in the upstream flow path and the downstream flow path 29 near the central portion 12. Next, an appropriate liquid elastic resin is injected into the gap, and the elastic wall member 82 of the second fluid flow path 80 and the disk-like shape of the upstream flow path and the downstream flow path 29 in the vicinity of the central portion 12. The seal 85 is formed. After the elastic material is cured, the housing 10 is removed from the mold. The structure resulting from this manufacturing process is depicted in FIGS. 8a to 8h. The seal 85 can help in providing a liquid and gas seal between the device 100 and the fluid flow line 102.

  Further, as depicted in FIGS. 11 a to 11 b, the sensor assembly can be secured to the housing so as to protrude into the channels 27, 29. This facilitates the manufacturing process because slides are commonly used to hold the sensor assembly 40 in place during the manufacturing process. However, as an alternative, the sensor assembly may continue to be placed into a cavity formed in the housing, if desired, in a manner similar to that described above with respect to FIGS.

  According to another aspect of the invention, a fluid sensor system is provided. The system includes a device for obtaining flow characteristics as described above, and a probe for receiving signals representative of fluid flow characteristics, and a processor for processing signals from the probes.

  For purposes of illustration and not as a limitation of the present invention, and as embodied herein, referring to FIG. 13, a flow measuring device 100 according to the present invention as described above is combined with a probe 90 and a processor 110. A system including it is schematically depicted.

  As already described, one aspect of the present invention includes providing a probe with a connector body having a predetermined shape, wherein the probe access port of the housing is connected to at least one of the upstream signal contact and the downstream signal contact. To ensure proper alignment, it has a corresponding shape.

  For example, as embodied herein, the probe 90 has a wedge-shaped connector body corresponding to the shape of the probe access port 39, as depicted in FIGS. 14a and 14b. Advantageously, the geometry of the probe access port 39 (periphery of the opening shown in dashed lines) eliminates the need for a lead frame to provide positioning between the probe 90 and the sensor assembly 40.

  In particular, probe 90 includes a connector body 95 having a plurality of leads 92 that are connected to a processor as described below. 14a and 14b, the corresponding shapes of the probe access port 39 and the connector body ensure proper positioning of the contacts 60, 62 on the sensor assembly 40 with the leads 92 on the probe 90. . Preferably, the geometric tolerance between the probe 90 and the probe access port 39 is sufficiently small so that the probe 90 can be press-fit or fitted into the probe access port 39. Further, the lead 92 can be configured to wipe the contacts 60, 62 when inserted as depicted in FIGS. 14a, 14b. Providing a wiping action ensures a stable fit and good electrical contact between the lead 92 and the contacts 60,62. In this way, as described above, the surface 39a and surface for providing the appropriate force to ensure contact between the probe 90 and the leads 92 on the probe 90 and the contacts 60, 62 on the sensor assembly 40. A contact is formed with 39b. The purpose is to ensure accuracy when placing a large number of contacts 92 on the probe 90 at the contacts 60, 62 on the sensor assembly 40. The fit between the lead 92 and the contacts 60, 62 must be assured to ensure a connection that does not create excessive noise that reduces the sensitivity of the system. Contacts 60, 62 are preferably made of gold, although other suitable conductive materials can be used.

  The probe 90 is preferably a flexible printed circuit element. More preferably, the probe includes a plurality of signal leads 92 that are disposed between two or more conductive shield layers 96 that are insulated from the signal leads 92 to minimize noise. Is done. The signal lead 92 defined by the flexible printed circuit element further defines or separately includes a spring element for improving contact. However, in order to prevent damage to the spring-based leads 92, the connector body 95 is configured to prevent excessive bending of the leads beyond specified limits. This is accomplished by accommodating the leads in a sufficient gap gap 98 defined in the connector body 95, as shown in detail in FIG. 14b. To protect the signal leads, the probe connector body can be overmolded with any suitable material, such as plastic or elastomer, or formed by other known techniques.

  Various other configurations and structures for the probe 90 can be used. For example, although the probe 90 is depicted here as a single flexible printed circuit element, a plug (not shown) with a plurality of conductive prongs can be used, and the probe access port 39 is connected to the sensor assembly 40. Defined by a plurality of passages (not shown) through the housing 10 configured to provide positioning between the electrical contacts 60 and the plurality of conductive prongs of the probe 90.

  According to a further aspect of the invention, the system further includes a fluid flow system having a fluid flow line in fluid communication with the fluid source. As embodied herein, with specific reference to FIG. 13 for illustrative purposes, a fluid flow line 102 is provided in communication with the fluid source 104. The fluid source 104 may be a pump 106 connected to the reservoir 108. In accordance with this aspect of the invention, a pump 106 is used to selectively send fluid through the first flow path, such as by positive displacement.

  Various other configurations for the fluid source 104 can be used. For example, the fluid source 104 may include a conventional venous supply reservoir, such as a bag or bottle, connected to the fluid flow line 102 for gravity supply. Preferably, a control valve (not shown) is provided in series with the fluid flow line 102 for controlling flow (as described below) by the processor in response to a signal from the device 100 to increase or decrease the flow rate. It is done. The pump and / or control valve can be adjusted manually or automatically.

  As already mentioned, the system includes a processor that processes the signal received by the probe. As is known in the art, the processor may be provided in various forms such as a software program running on a conventional workstation, hardware embedded in a chip, or a device embedded in hardware. Can do.

  According to a further aspect of the invention, the processor controls the pump in response to a signal obtained from the sensor by the probe.

  For purposes of illustration and not limitation of the present invention, with particular reference to FIG. 13, a system including a processor 110 is presented. The processor 110 is programmed to change the flow output of the pump 106 in response to signals obtained from the upstream fluid pressure sensor 52 and the downstream fluid pressure sensor 56 to provide a desired fluid flow rate. It may be a control circuit. In the alternative, the processor 110 may be provided in the form of a computer workstation (not shown). Examples of suitable processors are Intel Corporation, Advanced Micro Devices, Inc. ("AMD Company"), and Integrated Device Technology, Inc. ("IDT") and many other types of embedded processors that are commercially available from a number of semiconductor manufacturers.

  In accordance with yet a further aspect of the present invention, the system can further comprise a locking mechanism for combining the housing with the fluid flow line. Generally, the locking mechanism has at least a non-locking state for receiving the housing and a first locking state for aligning the housing with the fluid flow line. In a preferred embodiment, the locking mechanism further includes a second locking state for positioning the probe within the housing.

  The locking mechanism can be provided in any of various forms and configurations. For example, one or more lever members each having a first state that can receive the housing 10 in communication with the fluid flow line 102 and a second state that aligns and secures the housing in place. Can be provided. The probe 90 can be inserted into the probe access port 39 and attached to one such lever member to communicate with the contact when the lever member is moved to its second state.

  For purposes of illustration and not limitation, the present invention is further embodied herein, and as shown schematically in FIGS. 15a-15c, a locking mechanism 120 connects the housing to the fluid flow line 102. It is provided to connect. The locking mechanism 120 is defined by a locking member 122 and a lever member defined in this embodiment as a cover 130. The cover 130 has two hinges 132 and 134. A hinge 132 connects the locking body 122 to the first cover portion 136 of the cover 130. A hinge 134 connects the first cover portion 136 of the cover 130 to the second cover portion 138 of the cover 130.

  As shown in FIG. 15 a, the locking mechanism can receive the flow measuring device 100 in the unlocked state. The flow measuring device 100 is adapted to receive a positioning mechanism 30 defined as one or more detents defined by corresponding protrusions when the locking mechanism 120 is in an unlocked state with the cover 130 fully open. Positioned within locking mechanism 120 to engage surface 124.

  The locking mechanism can be changed from the non-locking state to the first locking state. As embodied herein and depicted in FIGS. 15a to 15b, the locking mechanism 120 engages the first cover portion 136 of the cover 130 and the tab 135 of the cover 130 about the hinge 132. By rotating it so as to engage with the tab 125 of the stop 122 (in the direction of the arrow “A”), it is changed to the first locked state. A mating is preferably provided, but other closure mechanisms can be used if desired. In this way, in the first locked state, the locking mechanism 120 keeps the housing 10 of the flow device 100 in a state where the positioning surface 30 of the housing 10 is aligned with the receiving surface 124. 102 is held at a predetermined position. In this way, the locking mechanism 120 ensures alignment between the fluid flow line 120 and the flow sensor device 100.

  Furthermore, the locking device can include a second locking state. For purposes of illustration and not limitation, the locking device 120 includes a second cover portion 138 centered about the hinge 134, as embodied herein in FIGS. 15b-15c. By rotating the tab 137 of the second cover portion 138 until it engages with the tab 127 of the locking body 122 (in the direction of the arrow “B”), the first locking state is changed to the second locking state. It is changed to. If desired, the second cover portion 138 can be operated independently of the first cover portion 136 and the second cover portion 138 for independent operation, eg, opposite the hinge 132. A hinge may be connected along the longitudinal edge 134 'to the locking body.

  In the preferred embodiment, as best seen in FIG. 15 c, movement of the locking mechanism second cover portion 138 to the second locking state advances the probe 90 to the probe access port 39 of the housing 10. As such, a probe may be provided on the second cover portion 138 or otherwise attached. As embodied herein, the second cover portion 138 defines an opening 138a that fits around the probe 90 to provide positioning. As a result, the second cover portion 138 ensures a firm contact for performing fluid flow measurement and the like, so that the probe 90 can be held in place.

  According to a further aspect of the present invention, a valve can be provided to selectively pass the flow through the second fluid flow path, as already described with respect to the embodiment of FIGS. 7a to 8h. The valve has a first state that allows the flow to pass through the second flow path and a second state that prevents the flow from passing through the second flow path. The system of this preferred embodiment is for the valve to change from the first state to the second state when the locking mechanism is moved from the first locked state to the second locked state. The actuator further includes.

  The second exemplary implementation of FIGS. 7a-8h according to the present invention having a second fluid flow path 80, as embodied herein for purposes of illustration and not limitation. The form is shown in Figures 15a-15c. The valve includes at least a portion of the second fluid flow path, where the valve is defined by a compressible wall member. As embodied herein, the second fluid flow path 80 is in a first state, ie, an open state, so that fluid can pass through in an initial state. After being placed into the locking mechanism 120, an actuator embodied as a protrusion 139 can be provided on one of the cover portions, the protrusion 139 moving the valve to the second state so that the second fluid It is pressed against the compressible wall member 82 of the flow path 80. As already explained, the cross section of the second fluid flow path 80 is preferably elliptical with a small radius at the apex. The dimension of the channel 80 parallel to the line of force applied by the protrusion 139 is smaller than the dimension of the channel 80 perpendicular to the line of force of the protrusion 139. In this manner, the force required to compress the compressible wall member and close the valve is relatively small. As embodied herein, the protrusion 139 is a pin, but other actuators may be used depending on the valve.

  According to a further aspect of the present invention, if desired, the second fluid flow path 80 can be opened by opening a valve to increase the flow through the flow measuring device 100. This can be accomplished by opening the appropriate cover portion, or by configuring the actuator, for example the protrusion 139, to move independently so that it can be moved to a position to actuate the valve.

  Various structures can be used for the protrusion 139. For example, a spring-biased pinch valve (not shown) can be used. Alternatively, the second fluid flow path 80 can be made of an elastic material that is biased to remain closed, and the resistance of the flow path can be overcome by increasing the fluid pressure. Alternatively, it can be overcome by applying a lateral force to open the oval channel. In addition or alternatively, the second fluid flow path 80 is initially sealed, and then it is necessary to deliver a large amount of useful drug to the patient through the device 100 in a relatively short time. If it does, a fragile membrane (not shown) can be provided that is ruptured by an actuator or rapid pressure rise.

  Further in accordance with the present invention, a method for obtaining flow characteristics of a fluid flow system is provided. The method includes providing the above-described device, directing fluid flow through the first fluid flow path, and in the first fluid flow path at the location of the upstream fluid pressure sensor and the downstream fluid pressure sensor. Obtaining a signal corresponding to the fluid pressure and determining a flow characteristic based on the signal. This method is described in detail in connection with the apparatus and system of the present invention.

  As embodied herein, with reference to FIGS. 9 and 10, fluid flows through the first fluid flow path 44 by applying a fluid differential pressure known to the inlet 46 and outlet 48 of the sensor assembly 40. be able to. As the fluid flows through the first flow path 44, a differential pressure reading is detected at the upstream position 54 relative to the downstream position 58. This difference in fluid pressure indicates that the fluid flow loses energy between position 54 and position 58 due to frictional interaction with the surface of the first flow path 44, particularly the flow restricting element 50. Reflects. These losses can be empirically correlated to the volumetric flow rate of a given fluid passing through the first flow path 44 at a selected temperature. Various sensors for obtaining such information are known, but in the preferred embodiment, capacitive pressure sensors are used.

Example I-Flow Measurement As embodied herein, each capacitive pressure sensor 52, 56 is used to measure pressure by detecting a change in the capacity of the pressure sensor. This measurement is accomplished by applying a voltage to each pressure sensor 52, 56. As a result, a voltage signal representative of the pressure sensor capacity, ie, a voltage signal representative of the flow pressure at either the upstream position 54 or the downstream position 58 at a particular point in time, is generated. The signal obtained from each pressure sensor 52, 56 is sent to the processor 110. FIG. 16 depicts the level of signal from each pressure sensor over time. The output of the upstream pressure sensor is indicated by reference numeral 151, and the output of the downstream pressure sensor is indicated by reference numeral 152. As shown, the levels of the signals indicated by reference numerals 151 and 152 are separated by a voltage level difference. This difference in signal level is indicated by ΔV and represents the pressure drop, ie, the flow rate, between the upstream position 54 and the downstream position 58.

  Since the relative voltage obtained from each pressure sensor 52, 56 represents a differential pressure, the fluid flow rate is empirically determined by a given difference in voltage output between the pressure sensor 52 and the pressure sensor 56. It is possible to Furthermore, in this empirical case, if the Reynolds number of the flow is known, or if the viscosity, density, and / or temperature of the fluid is known, then using known techniques, Features can be determined or calculated. Thus, based on empirical experiments and information, the desired flow characteristics for the fluid passing through the first fluid flow path, as well as the voltage signal received from the pressure sensor, as well as the known or rigorously evaluated fluid Can be determined based on the physical characteristics of

  According to a further aspect of the invention, the determining step can include determining a pressure difference between the upstream fluid pressure sensor and the downstream fluid pressure sensor. Further, the determining step can include calculating or otherwise determining the flow rate of the fluid through the first fluid flow path based on the pressure differential rather than the signal measurement.

  Further, the method of the present invention determines the actual pressure difference between the upstream pressure sensor 52 and the downstream pressure sensor 56 instead of empirically correlating the level of the output signal directly to the flow rate. including. The flow passes through the first flow path 44 of the sensor assembly 40 by passing through the inlet 46, the upstream position 54, the flow restricting element 50, the downstream position 58, and the outlet 48, as seen in FIGS. Pass through. Although it is not necessary to actually convert the signal output into a pressure reading before determining the flow rate through the first fluid flow path 44 of the sensor assembly 40, it is desirable to obtain an actual pressure measurement. A situation can arise. For example, knowing the total pressure at position 54 of upstream pressure sensor 52 or position 58 of downstream pressure sensor 56 or the differential pressure across flow restrictor 50 is operating in a situation where the system requires monitoring. May be useful in some cases. The flow rate of the fluid flow through the first flow path 44 can then be calculated based on the pressure difference measured and calculated by the upstream pressure sensor 52 and the downstream pressure sensor 56.

Example II-Air Detection According to another aspect of the present invention, the determining step includes detecting the presence of air in the first fluid flow path. Detecting air in the first fluid flow path can include identifying convergence between a signal received from the upstream fluid pressure sensor and a signal received from the downstream fluid pressure sensor.

  As embodied herein, the step of determining the presence of air in the first fluid flow path 44 determines that the pressure difference measured by the pressure sensors 52, 56 approaches zero. Contains.

  16 to 17 illustrate signal outputs of the pressure sensors 52 and 56 when a bolus of 50 microliters of air is detected in the first flow path 44. The first signal trajectories 151 (FIG. 16) and 156 (FIG. 17, with the same data stretched in time) can be seen above zero units, and the second signal trajectory 158 is zero units. Where each unit may be an indicator of voltage or relative pressure. During normal liquid flow, the signal levels are separated by several units as described above. On the other hand, as air is injected into the line, the voltage signals converge towards each other, reflecting the reduced pressure differential and the presence of air in the flow line. The convergence of this signal trajectory is that the presence of gas mixed in the liquid has a large difference in fluid resistance that causes pressure equalization, while the air quickly traverses the restriction and the first flow path 44. This is due to the generation of a pressure shock wave at the downstream position 58.

  For example, when a mass of air (ie, a bubble) passes through the sensor assembly, the bubble envelops both the upstream and downstream pressure sensors, causing the pressure differential to approach zero. The volume of the sensor assembly can be reduced so that very small bubbles (about 1 microliter) can be detected. Furthermore, when the air passes the sensor, a sudden change in fluid resistance creates a substantial transient spike. By monitoring these transients, bubbles can be distinguished from upstream closure. In a preferred embodiment, the upstream pressure sensor 52 and the downstream pressure sensor 56 are of the capacitive type disclosed, for example, in US Pat. No. 6,445,053, entitled “Micro-Machine Absolute Pressure Sensor”. It is a pressure sensor and can be arranged with a spacing of less than 1 mm. This small two-sensor assembly embodiment allows detection and measurement of small bubbles as small as 1 μl. The conventional fluid flow measurement system detects bubbles of about 50 μl, but cannot accurately measure the size of the bubbles. In a preferred embodiment of the present invention, bubbles of 1 μl or more can be detected. Generally, this system detects bubbles in the range of 1 μl to 50 μl. Larger bubbles can also be detected, but are limited only by the time measurement of the system.

In general, the degree of convergence of the signal represents the amount of air detected in the flow path. That is, when the flow path is essentially filled with air, the pressure difference drops to zero. In small volume sensor assemblies, air bubbles quickly pass through the assembly. As the bubble passes through the sensor assembly, the upstream pressure P1 is restored to the original flow value. As shown in FIG. 20, the size of the bubble can be determined by measuring the time Δt for the bubble to cross the device. The bubble volume can be calculated by the following equation.
Bubble volume = bubble velocity × Δt × channel cross-sectional area

  For example, if the system includes an upstream pump that controls the actual flow of fluid, the actual air volume can be quantified.

Example III-Pulsed Flow According to yet another aspect of the invention, intermittently pulsing the fluid passing through the first fluid flow path, as well as the fluid delivered each time the pump is pulsed. A method is provided that further comprises detecting the pressure of the fluid in the first fluid flow path using the upstream fluid pressure sensor and the downstream pressure sensor to determine the amount. This method for obtaining flow characteristics is particularly useful when the flow rate through the fluid flow system is sufficiently small and background noise prevents continuous flow signal measurements.

  According to this aspect of the invention, the trajectory of each signal gains amplitude, drops to zero, and then exhibits a pulsed behavior that is evident by repeating the transition as expected in a periodic flow. A data signal output (not shown) similar to that of FIG. 16 results. The region below the signal curve can be integrated and empirically correlated to a defined volume of fluid that has flowed through the first fluid flow path over a selected time period. This is advantageous when it is desired to deliver a very small amount of beneficial agent to the patient over a long period of time. This is because a slight steady flow over such a time does not produce a sufficiently high differential pressure signal for detection.

  Specifically, when performing a method according to this aspect of the invention, signals received from pressure sensors 52, 56 during a short occurrence of fluid flow and associated transients in the function of flow detection and integration. It is useful to be able to receive and compile only. By changing the time interval between short occurrences of fluid flow, changing the average flow to a wide range of delivery rates can facilitate system calibration and ensure accurate operation. it can.

  According to yet another aspect of the invention, a method is provided wherein a housing provided by a housing process includes a second fluid flow path and a valve for selection of flow through the second fluid flow path. . The valve has a first state that allows the flow to pass through the second flow path and a second state that prevents the flow from passing through the second flow path. The method further includes opening the valve to increase flow through the housing.

  As described above, the second fluid flow path 80 can be provided in the housing 10 for illustrative purposes only. When the flow sensor device 100 is placed in the second locked engagement assembly 120, the protrusion 139 closes the second fluid flow path as depicted in FIG. 15c. For example, by opening the valve 140 by opening a cover member to prime the third flow system to purge all air, or in a patient emergency or other situation where a sudden increase in flow is natural. In some cases, the flow through the housing 10 can be increased.

Example IV-Detection of an Occlusion According to a further aspect of the invention, a sensor assembly can be used to determine the presence or absence of an occlusion (including a partial occlusion) in a fluid line and the location of the occlusion. As shown in FIG. 18, the upstream side of the fluid line when the upstream pressure sensor detects a pressure drop while the downstream sensor detects a relatively constant pressure. Occlusion can be detected. As shown in FIG. 19, when the upstream pressure sensor detects a relatively constant pressure and the downstream pressure sensor detects an increase in downstream pressure, the fluid line A blockage on the downstream side can be detected.

  Those skilled in the art will appreciate that various modifications or changes can be made to the apparatus, methods, and systems of the present invention without departing from the spirit and scope of the invention. That is, the present invention also includes modifications and variations that are encompassed by the claims and their equivalents.

1 is a side view of a first exemplary embodiment of an apparatus for obtaining flow characteristics according to the present invention. FIG. 1 is a cross-sectional view of a first exemplary embodiment of an apparatus for obtaining flow characteristics according to the present invention. 1 is a cross-sectional view of a first exemplary embodiment of an apparatus for obtaining flow characteristics according to the present invention. FIG. 2 is a plan view of the apparatus of FIGS. 2 is a side cross-sectional view of the apparatus of FIGS. 2 is an end view of the apparatus of FIGS. 2 is a perspective view of the apparatus of FIGS. 2 is a plan view of a cap portion for use with the apparatus of FIGS. 1a to 1c. FIG. FIG. 2 is a side view of a cap portion for use with the apparatus of FIGS. FIG. 2 is a cross-sectional end view of a cap portion for use with the apparatus of FIGS. FIG. 2 is a cross-sectional end view of a cap portion for use with the apparatus of FIGS. 2 is a cross-sectional end view of the apparatus of FIGS. FIG. 2 is an enlarged detail view of the apparatus of FIGS. FIG. 2 is an enlarged view of a selected portion of the apparatus for obtaining the flow measurements of FIGS. 1a-1c. FIG. 6 is a side view after a first stage of the manufacturing process for a second exemplary embodiment of a flow measuring device according to the present invention. FIG. 6 is a plan view after a first stage of the manufacturing process for a second exemplary embodiment of a flow measuring device according to the present invention; FIG. 6 is a cross-sectional view after a first stage of the manufacturing process for a second exemplary embodiment of a flow measuring device according to the present invention. FIG. 6 is a cross-sectional view after a first stage of the manufacturing process for a second exemplary embodiment of a flow measuring device according to the present invention. FIG. 6 is a cross-sectional view after a first stage of the manufacturing process for a second exemplary embodiment of a flow measuring device according to the present invention. FIG. 7b is a plan view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is an end view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 7b is a cross-sectional view of the apparatus of FIGS. 7a to 7e after a second stage of the manufacturing process. FIG. 2 is a schematic view of a sensor assembly portion of an apparatus according to the present invention for obtaining a flow measurement. FIG. 2 is a schematic perspective view of a sensor assembly portion of an apparatus according to the present invention. FIG. 7b is a side cross-sectional view of the apparatus of FIGS. 7a to 7e according to the present invention. FIG. 7b is an enlarged detail view of the apparatus of FIGS. 7a to 7e according to the present invention. FIG. 7b is a perspective view of the device of FIGS. 7a to 7e according to the present invention. 1 is a schematic diagram of a fluid flow system according to the present invention. 1 is a perspective view of an exemplary embodiment of a probe for use according to the present invention. FIG. FIG. 3 is an enlarged detail view of an exemplary embodiment of a probe for use in accordance with the present invention. FIG. 3 is a schematic view of an exemplary locking mechanism for use in accordance with the present invention. FIG. 3 is a schematic view of an exemplary locking mechanism for use in accordance with the present invention. FIG. 3 is a schematic view of an exemplary locking mechanism for use in accordance with the present invention. FIG. 6 depicts flow measurement data obtained using an apparatus according to the present invention. FIG. 3 depicts air detection data obtained using an apparatus according to the present invention. FIG. 6 depicts pressure sensor data for a blockage downstream of a fluid line using a device according to the present invention. FIG. 6 depicts pressure sensor data for an upstream blockage of a fluid line using a device according to the present invention. FIG. 6 depicts pressure sensor data for bubbles crossing a device according to the present invention.

Claims (15)

A method for obtaining flow characteristics of a fluid flow system, the method comprising:
In order to obtain a flow rate measurement value , the disposable flow sensor device is provided with a process of integrating the delivery flow path of the medical fluid that is a liquid , and the integrating process includes:
Positioning the housing so as to define an integral part of a delivery path for liquid medical fluid;
Positioning the sensor assembly within the housing in a delivery path for the medical fluid that is a liquid, the sensor assembly comprising:
A body defining a first fluid flow path having an inlet and an outlet;
A flow restricting element located along the first fluid flow path between the inlet and the outlet;
An upstream fluid pressure sensor for detecting upstream fluid pressure at an upstream position of the first fluid flow path between the inlet and the flow restricting element;
A downstream fluid pressure sensor for detecting downstream fluid pressure at a downstream position of the first fluid flow path between the flow restriction element and the outlet;
An upstream signal contact connected to the upstream fluid pressure sensor;
Connected to the downstream side fluid pressure sensor and a downstream-side signal contact and Nde including,
The housing viewed including the upstream portion and downstream portion, the upstream portion, downstream defining an upstream port to the inlet in fluid communication with the sensor assembly, the downstream portion, to an outlet in fluid communication with the sensor assembly Defining a port, the housing further defining a probe access port configured to provide probe access to at least one of the upstream signal contact and the downstream signal contact, the method further comprising:
Directing a fluid flow that is a liquid through the first fluid flow path;
Obtaining a signal corresponding to the fluid pressure in the first fluid flow path at the location of the upstream fluid pressure sensor and the downstream fluid pressure sensor;
Determining flow characteristics based on the signal.   The method of claim 1, wherein the determining step includes determining a pressure difference between the upstream fluid pressure sensor and the downstream fluid pressure sensor.   The method of claim 2, wherein the determining step further comprises calculating a flow rate of fluid passing through the first fluid flow path based on the pressure differential.   The method of claim 1, wherein the determining comprises detecting the presence of air in the first fluid flow path.   5. The step of detecting the presence of air in the first fluid flow path includes identifying the convergence and characteristic waveform of the signal from the upstream fluid pressure sensor and the signal from the downstream fluid pressure sensor. The method described in 1.   Further comprising delivering fluid in intermittent pulses through the first fluid flow path, and further comprising determining the amount of fluid delivered by each pulse; The method of claim 1, comprising detecting fluid pressure in the first fluid flow path. A housing provided in the housing process;
A second fluid flow path;
A valve for selective flow through the second fluid flow path, the valve having a first state that allows the flow to pass through the second fluid flow path, and a flow in the second fluid flow path. A second state for preventing passage through the flow path,
The method of claim 4, further comprising opening a valve to increase flow through the housing.   The method of claim 1, wherein the determining includes detecting the presence of an occlusion in the fluid flow system.   The method of claim 8, wherein detecting an occlusion in the fluid flow system further comprises detecting the location of the occlusion.   The method of claim 9, wherein detecting the occlusion includes identifying a characteristic waveform of the signal from the upstream fluid pressure sensor and the signal from the downstream fluid pressure sensor.   The determining step calculates the volume of air by detecting the presence of air in the first fluid flow path and determining the amount of time that air is present in the first fluid flow path. The method of claim 1, comprising: A method for obtaining flow characteristics of a fluid flow system, the method comprising:
Providing a device for obtaining flow measurements, said device comprising:
A sensor assembly, wherein the sensor assembly defines a first fluid flow path having an inlet and an outlet, and a flow restricting element positioned along the first fluid flow path between the inlet and the outlet; An upstream fluid pressure sensor for detecting upstream fluid pressure at a location upstream of the first fluid flow path between the inlet and the flow restricting element, and a first fluid between the flow restricting element and the outlet A downstream fluid pressure sensor for detecting downstream fluid pressure, an upstream signal contact connected to the upstream fluid pressure sensor, and a downstream side connected to the downstream fluid pressure sensor at the downstream position of the flow path A signal contact, the device further comprising:
A housing including an upstream portion and a downstream portion, wherein the upstream portion defines an upstream port in fluid communication with the inlet of the sensor assembly, and the downstream portion includes a downstream port in fluid communication with the outlet of the sensor assembly. The housing further defining a probe access port configured to provide probe access to at least one of the upstream signal contact and the downstream signal contact;
Directing a fluid flow through the first fluid flow path;
Obtaining a signal corresponding to the fluid pressure in the first fluid flow path at the location of the upstream fluid pressure sensor and the downstream fluid pressure sensor;
Determining flow characteristics based on the signal,
The method wherein the determining includes detecting the presence of air in the first fluid flow path. 13. The step of detecting the presence of air in the first fluid flow path includes identifying convergence and characteristic waveforms of signals from upstream fluid pressure sensors and signals from downstream fluid pressure sensors. The method described in 1. A housing provided in the housing process;
A second fluid flow path;
A valve for selective flow through the second fluid flow path, the valve having a first state that allows the flow to pass through the second fluid flow path, and a flow in the second fluid flow path. A second state for preventing passage through the flow path,
The method of claim 12, further comprising opening a valve to increase flow through the housing. A method for obtaining flow characteristics of a fluid flow system, the method comprising:
Providing a device for obtaining flow measurements, said device comprising:
A sensor assembly, wherein the sensor assembly defines a first fluid flow path having an inlet and an outlet, and a flow restricting element positioned along the first fluid flow path between the inlet and the outlet; An upstream fluid pressure sensor for detecting upstream fluid pressure at a location upstream of the first fluid flow path between the inlet and the flow restricting element, and a first fluid between the flow restricting element and the outlet A downstream fluid pressure sensor for detecting downstream fluid pressure, an upstream signal contact connected to the upstream fluid pressure sensor, and a downstream side connected to the downstream fluid pressure sensor at the downstream position of the flow path A signal contact, the device further comprising:
A housing including an upstream portion and a downstream portion, wherein the upstream portion defines an upstream port in fluid communication with the inlet of the sensor assembly, and the downstream portion includes a downstream port in fluid communication with the outlet of the sensor assembly. The housing further defining a probe access port configured to provide probe access to at least one of the upstream signal contact and the downstream signal contact;
Directing a fluid flow through the first fluid flow path;
Obtaining a signal corresponding to the fluid pressure in the first fluid flow path at the location of the upstream fluid pressure sensor and the downstream fluid pressure sensor;
Determining flow characteristics based on the signal,
The determining step calculates the volume of air by detecting the presence of air in the first fluid flow path and determining the amount of time that air is present in the first fluid flow path. Including the method.

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