Flow control device and method

Sept. 19, 1961

W. E. WHEELER

3,000,540

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FLOW CONTROL DEVICE AND METHOD

Filed Aug. 8, 1957

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3,000,540

Patented Sept. 19, 1961

United States Patent Office

3,000,540

FLOW CONTROL DEVICE AND METHOD Warren E. Wheeler, Columbus, Ohio, assignor, by mesne assignments, to Baxter Laboratories, Inc., Morton Grove, HI., a corporation of Delaware

Filed Aug. 8, 1957, Ser. No. 677,109

Claims. (Cl. 222—14)

This invention, relates to a flow control device and method and in particular to a device and method for limiting the volume of parenteral fluid dispensed from a container.

In the administration of parenteral fluids, the fluids are withdrawn by gravity flow from a sterile, sealed container through a suitable outlet passage. It has been found desirable in many instances to administer to a patient less than the entire volume of fluid in the container. Manually operated shut-off devices as now used in the art permit the administration of such limited volumes but have the serious disadvantage of requiring an attendant to operate them at the proper time. Instances have occurred wherein the shut-off devices were left open, resulting in seriously detrimental over-administration, or flooding of the patient.

The principal feature of this invention is the provision of new and improved means for limiting the volume of parenteral fluid dispensed from a container.

Another feature is that the means limits the quantity of liquid dispensed while maintaining a head of the liquid in the container above the outlet passage.

A further feature of the invention is that the limiting means comprises means for introducing a predetermined volume of air into the container to replace liquid dispensed therefrom, whereby flow from the container is automatically stopped upon completion of the delivery of the predetermined quantity of air from the last-named means.

Still another feature is the provision of such a flow limiting means comprising a collapsible enclosure communicating with the interior of the container through inlet means associated with the container.

A yet further feature is that the inlet means include an air filter device and the collapsible enclosure is sealingly secured to a portion thereof externally of the container.

A still further feature is that the enclosure is provided with means for readmitting air thereinto to permit reuse thereof.

Another feature is that the means for readmitting air comprises a manually operable valve member.

Other features and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawings, wherein:

FIG. 1 is an elevational view of a parenteral fluid dispensing system having a flow limiting means embodying the invention; and

FIG. 2 is an enlarged fragmentary elevational view partially in section of the dispensing system of FIG. 1.

In the exemplary embodiment of the invention as disclosed in the drawings, a parenteral fluid dispensing system is shown to comprise a container 10 arranged to be supported in an inverted position by means of a suitable bracket 11. A stopper 10α sealingly closes the open top 106 of the container. Parenteral fluid P is dispensed from container 10 by gravitational flow through an outlet passage extending through stopper 10α and defined by means such as a cannula 12α of a drip meter 12. To permit the flow of the fluid from the container, a fluid, such as air, is introduced into the container to replace the parenteral fluid dispensed, otherwise the vacuum resulting in the container when a portion of the parenteral fluid is dispensed precludes further dispensing. A con2 ventional means for providing the replacement air includes a stand pipe 13 extending from stopper 10α through container 10 to a point adjacent the bottom thereof (this point is resultingly adjacent the upper portion of the 5 container when the container is in the inverted position as shown in FIG. 1). To pass air from outside the container through stopper 10α to tube 13, an air filter 14 is provided. A suitable air sterilizing or filtering means such as cotton wad 14α is carried in a cup-shaped outer 10 end 14b of air filter 14. A pointed tubular portion 14c extends from end 14b to permit insertion of the air filter through stopper 10α to communicate with stand pipe 13.

The parenteral fluid P is delivered from drip meter 12 through a suitable tube or duct 15 and an injection needle 15 16 to the patient. A device for regulating the rate of flow of the parenteral fluid through tube 15, such as regulator 17, may be associated with the tube when desired.

As discussed above it is often desirable to limit the 2u volume of parenteral fluid administered to a quantity less than the total quantity originally in container 10. For this purpose, a volume limiting device 18 is associated with means 14 for introducing the fluid replacing air into the container. Device 18 limits the volume of the re25 placing air to a predetermined quantity as determined by the quantity of parenteral fluid desired to be dispensed. As best seen in FIG. 2 of the drawings, volume limiting device 18 comprises a collapsible enclosure having one end 18α sealingly secured to end 146 of air filter 14. To 30 permit clearance of the enclosure with the adjacent drip meter 12, end 18α is off-set from the center of the enclosure.

Device 18 may be arranged so that in its extended, or uncollapsed, condition it encloses the predetermined 35 quantity of air. As the parenteral fluid is withdrawn from container 18, the enclosed air passes from the interior of device 18 through air filter 14 and stand pipe 13, and into the upper portion of container 10 to replace the dispensed fluid. The air is withdrawn from device 18 ⁴⁰ until it is fully collapsed. As no further replacing air is now admitted through filter 14 and stand pipe 13 into container 10, further flow of the parenteral fluid from the container is prevented.

To permit dispensing of additional quantities of the -⁵ parenteral fluid when desired, device 18 may be formed of a resiliently collapsible material such as latex rubber. A material found to be quite satisfactory for this use is that 'known as “Penrose” tubing having a wall thickness of the order of .01 inch. If it is desired to dispense a second ⁰⁰ quantity of parenteral fluid from the container subsequent to the dispensing of a first quantity, air is readmitted into the device and a similar dispensing operation, as described above, performed. To facilitate the readmission of air into device 18 readily manipulatable ⁵⁸ valve means 19 are provided. Valve means 19 may be of any suitable construction and is illustratively shown as a plug removably stopping an air inlet passage 20 through the end 186 of device 18 opposite the end 18α secured to air filter 14. A retaining head 19α on the inner end of valve means 19 serves to prevent loss of the valve means by maintaining the valve means associated with device 18 when in the open, or air admitting, position. When valve means 19 is opened, air may pass into the interior of device 18 and permits the device to restore itself to the ⁶⁵ extended arrangement, as seen in FIG. 2. Subsequent dispensing operations similar to that discussed above may be performed until the entire volume of fluid is dispensed from container 10.

γθ Alternatively, device 18 may be arranged to enclose a quantity of air comparable to the entire volume of container 10 and a clamp 21 associated therewith to con

3,000,540 ³ strict the mid-portion of the device as desired and provide a controlled volume of the portion 18c of the device comunicating with end 18α. Illustratively, where the volume of container 10 is 100 cc., the volume of device 18 may be 100 cc. Scale markings 22 may be arranged on device 18 to indicate, for example, 25, 50 and 75 cc. portions of the device. Should it be desired to administrate seriatim 50 cc. volumes of parenteral fluid P, clamp 21 may be set at the scale marking corresponding to a 50 cc. volume of portion 18c and operated to constrict sealingly device 18 at that point. When the air has been withdrawn from portion 18c and 50 cc. of fluid P has been dispensed, clamp 21 may be opened to readmit air into portion 18c and a subsequent dispensing operation, as discussed above, may be carried out.

Means, such as cord 23, may be provided to retain the clamp in association with device 18 and prevent loss of the clamp when it is not in use.

It should be noted that the use of volume limiting device 18 permits tip 126 of cannula 12α to have a head of fluid maintained thereabove until the container is substantially empty. This precludes undesirable introduction of air into the parenteral fluid being dispensed. Further, it should be noted that because the device 18 is associated with the inlet outwardly of air filter 14, device 18 need not be sterile and may be removed and replaced, and reused as desired. Further, the ready removability of device 18 permits the use of the device with a plurality of different containers each having its own air inlet means.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.