US 3000540 A
Description (OCR text may contain errors)
Sept. 19, 1961 w. E. WHEELER 3,000,540
FLQW CONTROL DEVICE AND METHOD Filed Aug. 8, 1957 States This invention relates to a ow 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In the administration of parenteral fluids, the iluids are withdrawn by gravity ow from a sterile, sealed container through a suitable outlet passage.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 uid in the container. Manually operated shut-oit 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 Jthe proper time. Instances have occurred wherein the shut-ott devices were left open, resulting in seriously detrimental over-administration,- or ooding of the patient.
The principal feature of this invention is the provision of new and improved means for limiting the volume of parenteral iluid 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 ow 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 iiow 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 ow limiting means embodying the invention; and
FIG. 2 is an enlarged fragmentary elevational view partially in section of the dispensing system of FIG. l.
In the exemplary embodiment of the invention as disclosed in the drawings, a parenteral fluid dispensing system is shown to comprise a container arranged to be supported in an inverted position by means of a suitable bracket 11. A stopper 10a sealingly closes the open top 10b of the container. Parenteral uid P is dispensed from container 10 by gravitational flow through an outlet passage extending through stopper 10a and defined by means such as a cannula 12a of a drip meter 12. To permit the ow of the uid from the container, a fluid, such as air, is introduced into the container to replace the parenteral uid dispensed, otherwise the vacuum resulting in the container when a portion of the parenteral iiuid is dispensed precludes further dispensing. A con- Patented Sept. 19, 1961 ventional means for providing the replacement air includes a stand pipe 13 extending from stopper 10a through container 10 to a point adjacent the bottom thereof (this point is resultingly adjacent the upper portion of the container when the container is in the inverted position as shown in FIG. l). To pass air from outside the container through stopper 10a to tube 1'3, an air lilter 14 is provided. A suitable air sterilizing or 4filtering means such as cotton wad 14a is carried in a cup-shaped outer end 14b of air filter 14. A pointed tubular portion 14C extends from end 14b to permit insertion of the air lter through stopper 10a to communicate with stand pipe 13.
The parenteral iluid P is delivered from drip meter 12 through a suitable tube or duct 15 and au injection needle 16 to the patient. A device for regulating the rate of flow' of the parenteral iluid 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 volume of parenteral uid 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 iluid replacing air into the container. Device y18 limits the volume of the replacing 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 18a sealingly secured to end 14h of air iilter 14. To permit clearance of the enclosure with the adjacent drip meter 12, end 18a is orf-set from the center of the enclosure. I
Device 1'8 may be arranged so that in its extended, or uncollapsed, condition it encloses the predetermined quantity of air. As the parenteral tiuid is withdrawn from container 10, the enclosed air passes from the interior of device 18 through air ilter 14 and stand pipe 13, and into the upper portion of container 10 to replace the dispensed fluid. The air is withdrawn fromI device 18 until it is fully collapsed. As no further replacing air is now admitted through iilter 14 and stand pipe 13 into container l10, further flow of the parenteral Huid from the container is prevented.
To permit dispensing of additional quantities of the parenteral iluid 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 quantity of parenteral fluid from the container subsequent to the dispensing of a rst quantity, air is readmitted into the device and a similar dispensing operation, as described above, performed. To facilitate the readmission of air into device 1-8 readily manipulatable 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 18b of device 18 opposite the end 18a secured to air lter 14. A retaining head y19a on the inner end of valve means 1'9 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 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.
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 constrict the mid-portion of the device as desired and provide a controlled volume of the portion 18C of the device comunicating with end 18a. Illustratively, where the Ivolume of container is 100 cc., the volume of device 18 may he 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 ISC and operated to constrict seal ingly device 18 at that point. When the air has been withdrawn `from portion 18C and 50 cc. of fluid P has been dispensed, clamp Z1 may be opened to lreadrnit 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 1'8 permits tip 12b of cannula 12a to have a head of fluid maintained thereabove unti-l the container is substantially empty. This precludes undesirable introduction of air into the parenteral iluid being dispensed. Further, it should be noted that because the device 18 is associated with the inlet outwardly of air iilter 14, device 18 need not be sterile and may be removed and replaced, and reused `as desired. Further, the ready removability of device 1S permits the use of the device with a plurality of different containers each having its own air inlet means.
While I have shown Iand described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Chang, therefore, in the construction and arrangement may be made without departing yfrom the spirit and scope of t-he invention as dened in the appended claims.
1. Means 'for 'limiting the volume of parenteral fluid dispensed from a container having an outlet passage and means having an outer portion externally of the container and providing an inlet -for passage of air into the container to` replace fluid dispensed through the outlet passage, comprising a collapsible enclosure removably sealingly secured to said outer portion to have communication solely with the inlet means during a dispensing of iluid from the container to provide ya predetermined volume of air to be `drawn through said inlet into t-he container as a result of a vacuum condition in the container, and means for readmitting air into the interior of the enclosure subsequent to a dispensing of rfluid from the container and precluding admission of air to the enclosure during such dispensing.
2. The means for limiting the volume of parenteral iluid dispensed, of claim l, wherein said means for readmitting air comprises a passage through the enclosure and a manually operable valve controlling the passage.
3. The means `for limiting the volume of parenteral fluid dispensed, of claim l, wherein the enclosure is elongated, said one portion is at one end of the enclosure and said means for readmitting air extends through the opposite end of the enclosure.
Reerences Cited in the file of this patent UNITED STATES PATENTS 98,177 Mathews, Jr Dec. 21, 1869 1,459,282 Cla-rk June 19, 1923 1,712,470 Pray May 7, 1929 2,214,260 Ravenscraft et al. Sept. l0, 1940 2,301,988 Wallenmeyer et al Nov. 17, 1942