CA1166916A

CA1166916A - Metering device for biological fluids

Info

Publication number: CA1166916A
Application number: CA000358756A
Authority: CA
Inventors: Gordon E. Smith
Original assignee: Quest Medical Inc
Current assignee: Quest Medical Inc
Priority date: 1979-09-04
Filing date: 1980-08-21
Publication date: 1984-05-08
Also published as: DE3031810A1; GB2059919A; JPS5636962A; GB2059919B; FR2464459A1; FR2464459B1

Abstract

METERING DEVICE FOR BIOLOGICAL FLUIDs ABSTRACT OF THE DISCLOSURE

A metering device for biological fluids is disclosed which is capable of metering precise amounts of biological fluid, such as intravenous fluid, from a pressurized source into a receiving body, such as a patient. A dual ccmpart-ment metering chamber is provided which emits pulses of fluid material of precisely equal volume from a pair of two compartments. Various embodiments of the metering chamber are disclosed and means are disclosed for varying the volume of fluid emitted by the chamber, and for actively pumping the fluid through the chambers so that the fluid source need not be under pressure.

Description

1 ~6~9~6 METERING DEVICE FOR BIOLOGICAL FLUIDS

TECHNICAL FIELD
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This invention relates to devices for handling biolog-ical fluids which are designed to meter the infusion of such biological fluids into a patient.

BACKGROUND OF THE PRIOR ART

It is conventional in hospitals, or wherever patients are treated, to introduce intravenous fluids into a patient through the use o~ an elevated intravenous (IV) bott:Le or bag suspended above the patient, which is connected by tubing to a needle inserted into the patient's vein. It is conventional in current hospital practice to control or meter the amount of fluid passing:from the bag into the patien;t by clamping the tube extending downward from the bag in such a manner that the tube is partially constricted, and then counting the drops passing through. the constriction to judge the amount: of fluid being transmitted to th`e patient.
.~ This method is inherently inaccurate inasmuch as the tubing tends to shift and stretch, thereby varying the size of the constriction in it, and inasmuch as the rate of flow of the : fluid is dependent upon the relative pressures of the fluid in the bag and~the blood pressure in the patient's veins, with both of these pressures tending to change.as circum-stances vary.

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-2- 1 The pr:ior patent art is generally cognizant to devices used to vary the drip rate from such an IV bottle or bag.
Some examples of patents showing such devices, which sub-stitute for the clamp, are U.S. Patents No. 3,234,943, No.

3, 796, 245, No. 3,826,137, No. 4,141,379 and No. 4,143,659.
At least two examples are known of apparatus designed to periodically pinch the tubing supplying the biological fluid to the patient in a timed manner so as to attempt to more accurately control the fluid introduced to the patient. Two examples of such devices are shown in U.S. Patents No.

4,061,1~2 t and No. 4,094,318. Other examples of flow control devlces used to control the flow of intravenous fluid into patients are shown in U.S. Patents No. ~,078,563, and No. 4,1~2,5~3.

BRIEF SUMM~RY OF THE INVENTION

The present invention is sun~larized in that a metering device for biological fluids includes a metering chamber having first and second compartments formed therein; first and s~cond inlet tubes connected respect.ively to the first and second compartments; first and second outlet tubes connected respectively to the first and second compartments;
- valve means connected to each of the inlet and outlet tubes such that f:Luid flow is allowed alternatively in both of the first inlet tube and the secona outlet tube and both of the ~5 second inlet and the firs~ outlet tube; and a movable pressure transmitting member positioned between the first and second compartments in the metering shamber, the pressure transmitting member forming a movable portion of each of the compartments and being movable between two positions such that the two compartments are simultaneously and alterna.tively filled and emptied, the movement of the pressure transmitting member displacing an equal amount o~ fluid and moving between the two positions so that the amount of fluid alternatively displaced from each of the two compartments is equal.

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It is an ohject of the present invention to provide a metering device for biological fluids that is capable of consistently and accurately metering the flow of such fluids.
It is a further objec-t of the present invention to construct such a metering device from biologically inert materials and yet keep the device relatively economical and relatively efficient to manufacture and operate.
It is yet another object of the present invention to provide such a device in which the rate of flow of the fluid through the device may be varied over a wide range. It is an advantage of the present invention in that this object may be :~
accomplished by varying the flow rate through the use of relative-ly economical and efficient electroni.c circuitry in a simple manner.
It is an advantageous feature of the present invention that it is independent of the fluid pressure in the source of the biological fluid as long as -that pressure is greater than the pressure of the biological body into which the fluid is being infused.
It is another feature of the present invention that the fluid is metered in a series of doses of e~ual volume, and it is another object of the present invention to provide at least one embodiment of such a metering device in which the amount of fluid metered in each dose may be varied.

~\~' 1 3 6~6 - 3a -Thus, -the present invention provides a metering device for metering the flow of biological fluids from a source into a receiving body comprising:
a metering ~hamber having first and second chamber walls therein each definirlg one side of first and second compartments formed in the metering chamber;
first and second inlet tubes connected respect-ively to the first and second compartments;
a main inlet tube connected to conduct fluid from the source to each of the ~irst and second inlet tubes;
first and second outlet tubes connected respect-ively to the first and second compartments;
a main outlet tube connected to conduct fluid from the first and second outlet tubes to the receiving body;
valve means connected to each of the inlet and outlet tubes such that fluid flow is allowad alternati~ely in both of the first inlet tube and the second outlet tube and in both of the second inlet tube and the first outlet tube; and a movable pressure transmitting member positioned between the first and second compartments in the metering chamber, the pressure transmitting member forming a movable portion of each of the compartments and being movable be-tween positions pressed against each of the ~irst and second chamber walls so that the two compartments are simultaneously and alternatively filled from the source and emptied into the receiving body, the movement of the pressure transmitting member displacing an amount of fluid equal to the volume of -tlle m~tering chamber in moving in either direction between the two positions so that the amount of fluid alternatively ~ .

(3 1 6 - 3b -displaced from each of the two compartments is equal to the volume of the metering chamber; and timing means controlling operation of the valve means to alternate the closing of the pairs of inlet and outlet tubes to control the volume of biological fluid supplied to the receiving body, an amount of Pluid e~ual to the volume of the metering chamber being supplied to the patient with each operation of the valve means by the timing means, the total overall rate of fluid flow supplied to the patient thus being determined only by the volume of ~he metering chamber and the rate of switching of the timing means Other objects, advantages, and ca~ure~ of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a cross-sectional view of a metering chamber for use in a metering device constructed in accordance with the present invention.

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~ 1 6fi~ 1 6 Fig. 2 is a plan view of a mounting block including therein the metering chamber of Fig. l.
Fig. 3 is a plan view of an casing suitable for instal-lation of the mounting block of Fig. 2.
Fig. 4 is a cross-sectional view of an alternative embodiment of a metering chamber ~or use in a metering device in accordance with the present invention.
Fig. 5 is a cross-sectional view taken along the line

5-5 in Fig. 4.
Fig. ~ is a cross-sectional view, similar to Fig. 5, showing the meter chamber of Fig. 4 wherein the pressure transmitting member is in its other position.
Fig. 7 is a cross-sectional view of yet another alter-native embodiment of a metering chamber for a metering device constructed in accordance with the present invention.
Fig. 8 is an elevation view of another alternative embodiment of a metering chamber for use in a metering device in accordance with the present invention.
Fig. 9 is another alternative embodiment of a metering chamber for use in a metering device in accordance with the present invention.
Fig. 10 is still one more a:Lternative embodiment of a metering chamber for use in a metering deviee construeted in accordanee with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Shown in Figs. 1-3 is a metering deviee for biologieal fluids constructed in accordance with the present invention.
Illustrated in Fig. 1 is the main operative eomponent of that device, a dual compartment metering chamber, generally indicated at 10. The metering chamber 10 of Fig. 1 is defined by a pair of eomplementary chamber walls 12 and 14.
The chamber walls 12 and 14 are eaeh formed of similar, relatively rigid and inelastie biologieally inert material, sueh as teflon or polyvinyl ehloride or similar plastics, or .

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l J ~ 6 may alternatively he formed of a flexible material, such as a silicone elastomer, if mounted so that they are inelastic.
Each of the chamber walls 12 and 14 is formed as an identical complementary hemispherical depression in a sheet of the material. The two sheets of material into which the chamber walls 12 and 14 are formed are joined together and press between them a movable pressure transmitting member 16. The pressure transmitting member 16 is formed as a ~embrane of relatively flexible material, such as silicone elastomer or a thin teflon sheet, which is pressed between the sheets of material of the chamber walls 14 and 12. The pressure transmitting member 16 is held between the sheets of material of the chamber walls 12 and 14 in such a fashion that the portion of the pressure transmitting member 16 inside of the chamber 10 is not stretched taught, but instead remains in a relatively limp, fle~ible condition. A first compartment 13 is defined between the chamber wall 12 and the pressure transmitting member 16 and a second compartment 15 is defined between the chamber wa]l 14 and the pressure transmitting member 16. The compartments 13 and 15 are completely sealed from each other by the pressure transmitting member 16. A
first inlet tube 18 and a first outlet tube 20 are connected through the chamber wall 12 to the interior of the first compartment 13 on one side of the pressure transmitting member 1~. Similarly a second inlet tube 22 and a second outlet tube 24 are connected through the chamber wall 14 into the interior of the second compartment 15 on the opposite side of the pressure transmitting member 16.
The metering chamber 10 together with the inlet and outlet tubes connected therewith as illustrated in Fig. 1 therewith is assembled as a complete unit and this unit is encapsulated in a larger mounting block of clear mounting material, generally indicated at 26, as shown in Fig. 2. As illustrated in Fig. 2, the mounting block 26 is a rectan-gular block of solid clear semi-flexible, thermoplastic material into which the metering chamber 10 has been en-capsulated. The material of the block 26 is selected so as .. . , .. __ _ to have some amount of flexibility and resiliency for reasons that will become apparent below. Formed extending com-pletely through the block 26 is a hole 28. The first inlet tube 18, which is connected to the first compartment 13, and the second outlet tube 24, which is connected to the second compartment 15, pass on a first side of the hole 28. By contrast, the ~irst outlet tube 20, which connects to the first compartment 13, and the second inlet tube 22, which connects to the second compartment 15, are arranged so as to pass on the other side of the hole 28 from the tubes 18 and 24. On the far side of the hole 28 from the metcring chamber 10, the inlet tubes 18 and 22 are joined to form a common main inlet tube 27, and similarly on the opposite side of the hole 28 from the chamber 10, the outlet tubes 20 and 24 are ]oined to form a main outlet tube 29., Shown in Fig. 3 is a casing 30 into which the mountin-g block 26 of Fig. 2 is mounted. The casing 30 may be made of metal, rigid plastic, or any other rigid material. As can be seen in Fig. 3, the casing 30 has a corresponding hole 32 formed in it corresponding in location and size to the hole 28 in the mounting block 26. Mounted on the back of the casing 30 and attached thereto at a pivot point 34 is a lever 36. The lever 36 has at its one end a rod 38 which is mounted at a right angle relative to the lever 36 and which 2S is positioned so as to extend into and through the hole 32 and the hole 28, in the casing 30 and the mounting block 26 respectively. Attached to the lever 36 is a tension spring - 40, which is attached to the lever 36 beyond the pivot point 34 and which is also attached at its other end to the casing 30 on the opposite side of the hole 32 thereln. At the far end of the lever 36, a pair of magnets 42 are attached on opposite sides thereof. A pair of magnetic coils 44 are arranged adjacent to the magnets 42 so as to be capable of attracting the appropriate magnet 42 thereto when properly energized. Appropriate electronic circuitry (not shown) for energizing the coils 44 is provided so as to alternately energize one and then the other of the coils 44 at a variable rate which may be altered as needed.

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The metering device for biological fluids as shown in Figs. 1-3 functions as a metering system independent of pressure to precisely and accurately meter biological fluids, such as intravenous fluid, from an IV bottle to a recei~ing body, such as a patient. The main operative component of the device, the metering chamber 10 as shown in Fig. 1, functions as two independent compartments of equal volume which are alternately filled and then emptied of the biological fluid at a rate that may be precisely controlled.
As can be seen in Fig. 3, the alternate energization of the coils 44 causes each of the coils to attract the respective magnet 42 thereto thereby pivoting the lever 36 about its pivot point 34. The tension spring 40 causes the lever 36 to act as an over-center mechanism so that it pivots to its extreme position whenever the point of attachment of the spring 40 to the lever 35 is brought past the pivot point 34. The operation of the lever 36 is actuated by the energi.zation of the coil 44 which is farthest from its associated magnet 42. This energization attracts the magnet 42 toward the coil 44 bringing the lever 36 past its pivot point thereby pivoting the lever 36 to its opposite position In either of its two position, the lever 36 is spring biased to press the rod 38 against one or the other side of the hole 32 and the hole 28 in the mounting block 26. ~hen the rod 38 is pressed against the interior of the hole 28 in the mounting block 26, the pressure of the rod 38 causes the two tubes adjacent to the side of the hole 28 to be pinched shut by the pressure of the rod on the relatively ~lexible material of the interior side surface of the mounting bloc~
26 around the hole 28. Thus the tubes 18 and 24 are pressed closed when the bar 28 is at one side of the hole 28 and the tubes 20 and 22 are pressed Glosed when the bar 38 is at the opposite side of the hole 28. Thereby alternatively one set and then the other set of the pairs of the tubes are closed and opened and the mechanism of Figs 2 and 3 func-tions as valve means to cause this closing and opening.
~ hen the rod 38 is in a first position, the tubes 18 and 24 are pinched shut and the tuhes 20 and 22 are opened.

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L.ooking to Fig. 1, it can be seen that when those tubes are closed, the interior of the second compartment 15 of the chamber 10 is connected through the second inlet tube 22 and through the main inlet tube 27 to the fluid source, i.e., the elevated IV bag. Simultaneously, the first outlet tube 20 from the first compartment 13 of the metering chamber 10 is open through the main outlet tube 29 to allow fluid flow to the patient. Since the fluid supply in the IV bag or other source is, by definltion, at a higher pressure than the fluid pressure ~f the patient, fluid is forced under pressure thxough the second inlet tube 22 into the interior of the second compartment 15. As the second compartment 15 fills with fluid, the pressure transmitting, member 16 is slowIy pressed upward thereby pressing fluid out of the first compartment 13 of the metering chamber 10 through the first outlet tube 20 and the main outlet tube 29 into the patient. When the pressure transmi-tting member 16 is pressed against the,interior of the chamber wall 12, no additional fluid can pass into the second inlet tube 22 and fluid flow stops. This condition remains until the rod 38 switches positions, to thereby open the tubes 18 and 24 and close the tubes 20 and 22. ~hen th:is occurs, the first inlet -tube 18 is connecte~ through the main inlet tube 27 to the fluid under pressure in the IV bag, and the fluid flows there-through into the firs~ compartment 13. As fluicl fills thefirst compartment 13, the flexible pressure transmitting men~er 16 is forced downwardly thereby displacing fIuid from the second compartment 15 through the second outlet tube 24 and the main outlet tube 29 into the patient. This flow continues until the pressure transmitting member 16 is pressed against the chamber wall 14 of the metering chamber 10 at which time fluid flow ceases.
As can be readily perceived by looking at Fig. 1, the volume of either the first and second compartments 13 and 15 formed within the metering chamber 10 are identical, i.e.
the entire volume of the interior of the chamber 10. Further-more since the pressure transmitting member 16 is flexible ~:166~
9_ and conforms to the interior shapes of the chamber walls 12 and 14, the volume of area through which the pressure trans-mitting member 16 moves between the two positions is identical in the two stages of the operation of the metering chamber 10. Thus, the two stages in the operation of the device result in the transmission of identical amounts of fluid to the patient. Note that since the amount of fluid is deter-mined by the volume of the compartments in the metering chamber 10, the pressure of the fluid within -the IV source is irrelevant in determining the volume of fluid supplied to the patient, as long as the pressure is sufficiently high in the source for the fluid pressure to cause the operation of .the de~ice. ~s long as the volume of ~he compartments in the metering chamber 10 is known, the volume of biological material supplied to the patient may be exactly controlled merely by controlling timing of the switching of the lever 36; This timing may be accomplished by a solid-state -timing circuit of a type well known to the art. In this way precise and exact amounts of bi.o:Logical fluids may be metered by a simple and inexpensive timing circuit in ~ manner which is entirely independent of the b:lood pressure of the patient, the fluid pressure in the IV bagl and any resistance in any of the tubing connected between the IV bag and the patient.
~lso, this device may be constructed of any of a wide variety of biologically inert materials.
Shown in Fig. 4 is an alternative embodiment of a dual compartmen-t chamber, generally indicated at 110 ! con-structed in accordance with the present invention. In the chamber 110, as in all other embodiments described below, simil.ar parts have been given similar reference numerals with a pref:ix, in this case 100, added thereto. The chamber 110 includes an outer compartment wall 112 defining a compartment 113 of a generally cylindrical tubular shape.and an inner com~partmental wall 114 defining a compartment lI5 also of a cylindrical tubular, although smaller, shape. As can be seen in Fig. 4, the compartment 113 defined by the wall 114 its entirely within the compartment wall 112.

Both of the compartment walls 112 and 114 are preferably formed of len~3ths of tubular materials which are tapered at their ends with the compartment wall 114 being received entirely within the compartment wall 112. The compartment wall 112 is formed of a relatively rigid material, such as thermoplastic tubing of teflon or PVC, while the compartment wall 114 is formed of a flexible material, such as a silicone elastomer. ~ respective inlet tube 118 and an outlet tube 120 are formed at opposite ends of the compar~ment wall 112 openi.ng into the compartment 113 with each of the inlet and outlet tubes 118 and 120 being narrowed in a portion of the compartment wall 112. Similarly, an inlet tube 122 and an outlet tube 124 are provided for the inner compartment 115, with the respec~ive inlet and outlet tubes 122 and 124 also being formed as narrowed end portions of the tubular com-partment wall 114 itself, and wlth the inlet and ou-tlets 122 and 12~ proceeding outward through sui~able sealed apertures provi.ded in the exterior of the oute,r compartment wall 112.
The pressure transmitting member 116 is identical in this embodiment with the inner compartment wall 114.
.In its operat.ion, the dual compartment chamber 110 serves as an effective subst.itute for the dual compartment chamber 10 of Fig. 1. In the chamber 110, the interior compartment wall 114 serves as the movable pressure trans-mitt:ing member 116 to be extended and contracted to separate -the two compartments 113 and 115 and to allow fluid pressures to be transmitted therebetween. ~s stated, in the chamber 110 the first compartment 113 is defined by the interior of the compartment wall 112 and the exterior of the compartment 30 wall 114, and the second chamber 115 is defined by the interior of the compartment wall 114 0 Figs. 5 and 6 show the two phases of the operation of the pressure transmitting member 116 of the metexing chamber 110. The chamber 110 is operated in a similar fashion to the chamber 10 inasmuch as i5 the respective inlet5 and outlets are alternatively opened and closed. Thus in the first mode, as shown in Fiq. 5, the inlet tube 122 is opened to the IV source, or other supply ~ ~ 66~
--ll--oE pressurized biological fluid, and the outlet tube 124 of the inner compartment llS is pinched closed. At the same time, the outlet tube 120 of the outer compartment 113 is opened while the inlet tube 11~ of that outer compartment 113 is pinched closed. This causes fluid to flow into the interior of the inner compartment 115 with the inner com-partment wall 11~ then expanding to fill the entire interior of the outer compartment wall 112, thus forcing all the fluid out of the outer compartment 113 and through the outlet tube 120 into the patient. Then the respective opening and closing of the inlets and outlets tubes i5 reversed, with the tubes 120 and 122 being pinched shut and the tubes 118 and 124 being opened. This change allows fluid to flow from the IV bag through the inlet tube 118 into the outer compartment 113. The fluid filling the compartment 113 under pressure slowly forces the fluid out of the inner compartment 115 and out through the outlet 124 into the patient. As the compartment 113 slowly fills, the interior compartment wall 114, which is acting as the pressure transmitting member 116, is collapsed to its configuration as shown in Fig. 6. The procedure is then reversed again and the interior compartment 115 is filled. It can be seen from viewing Figs. 5 and 6 that the area on the interior of the exterior compartment wall 11;2 remains constant. Simi-larly, the portion of that area taken up by the interiorcompartment wall 114 also remains fixed. Therefore the volume of material inserted on the interior of the inner compartment 1].5 when it is filled is exactly the same as the volume of material whlch fills the interior of the outer compartment 113 when that compartment is filled. Thus the dual compartment chamber 110 also functions as a metering chamber having two chambers exactly equal in volume which may be alternatively filled and emptied.
The chamber 110 is particularly designed for the metering of very small amounts of biological fluids inasmuch as the tubing of the compartment walls 112 and 114 may be selected to be of as small a size as is desired. Thus the chamber 110 could be used to meter small amounts of rela-1 ~ . 6 tively active biological fluids, such as drugs, hormones, vitamins or other substances, in-to a patlent. It is also conceivable that the metering chamber 110 could be entirely implanted, along with suitable valving mcans and con-trol apparatus, into a patient to continually meter small amounts of the fluid into the patient over a long period of time.
Shown in Fig. 7 is another alternative embodiment of a dual compartment metering chamber, generally indicated at 210, constructed in accordance with the present invention.
The chamber ~10 is formed as an elongated cylindrical chamber hollow m its interior. First and second compart-ments 213 and 215 are formed at opposite ends of the cylin-drical chamber 210. A movable pressure transmitting member 216, in the form of a movable disk equal in diameter to the interior diameter of the chamber 210, moves freely within the chamber 210. Suitable inlet tubes 218 and 222 are provided to each of the chambers 213 and 215, and suitable outlet tubes 220 and 224 are also provided exiting from the compartments 213 and 215. Suitable means are provided, but not shown herein, to alternatively close the inlet tube 218 and the outlet tube 224 simultaneously, and the inlet tube 222 and the outlet tube 220 simultaneously, so as to alterna-tively fill and empty each of the compartments 213 and 215 in the manner similar to that shown in the embodiment in Figs. 1-3. Also included in the chamber 210 is a volume altering mechanism, indicated at 246. The volume altering mechanism 246 is formed as a elongated screw tapped into a hole provided for it in the center of the end of the com-partment 210 forming the end of the compartment wall 212.
The mechanism 246 includes an elongated threaded rod pro-truding through that end piece and a narrow knob prc,vided at its outer end so -that it may be manually manipulated to adjust the amount of the mechanism extending into the com--partment 213. The mechanism 246 limits the movement of the pressure transmitting member 216 to limit the amount of fluid displaced in each operation of the chamber 210. Thus, although the compartment 213 may be larger than the com-partment 215, equal volumes of fluid are always îssued from . . , -. .' ~
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, 9 :~ 6 the chamber 210 since the trave:l of the pressure transmitting, member 216 is equal regardless of which compartment is being emptied.
Shown in Fig. 8 is another alternative embodiment o~ a dual compar-tment metering chamber, generally indicated at 310, constructed in accordance with the present invention.
The chamber 210 is formed somewhat similarly to the chamber 10 of Figs. 1-3 in that the chamber walls 312 and 314 are complementary concave rigid walls which interfit to define a finite area therebetween, and which also hold the edges of a ~lexible pressure transmitting member 316, in the form of a diaphragm of thin sheet material, therebetween. A first compartment 313 is defined between the chamber wall 312 and the pressure transmitting member 316 and a second chamber 315 is defined be-tween the chamber wall 314 and the pressure transmitting member 316. Appropriate inlet and outlet tubes 318 and 320 are provided to the compartment 313 and slmilar inlet and outlet tubes 322 and 324 are pro~ided to the compartment 31S. A pair of valve mechanisms 352 and 354 are provided in the inlet and outlet tubes between the chamber 310 and a main tube 326 and a main outlet tube 323. The valve mechanism 352 simultaneously controls the inlet tube 318 and the outlet tube 324 while the valve mechanism 354 simultaneously controls the inlet tube 322 and the outlet t'ube 320 in a complementary fashiol~ relative to the operation of the valve mechanism 352. The metering chamber 310 of Fig~ 8 is mounted on a mounting plate 350 having a graduated scale marked thereon with suitable indicia. ~n adjustable bar clamp 356 is provided which may be clamped over the chamber 310 and the mounting plate 350.
In its operation, the metering chamber 310 operates as an adjustable metering chamber so that the amount of fluid emitted from the chamber 310 during each alternative operation o~ the device may be altered as desired. To accomplish an alteration of the volume, it is merely necessary to remove and replace the clamp 356 in an alternative point along the mounting plate 350. Inasmuch as the various inlet and ' .. ..... , ~

outlet tubes to the two compartments 313 and 315 are all connected at one end of the metering chamber 310, only that L~ortion of the metering chamber 310 between the clamp 356 and the inlet and outlet tubes is operative when the clamp 356 is applied. The indicia marked on the mounting plate 350 indicates the approximate volume of material which is emitted by the chamber 310 in each operatlon thereof cor-responding to that particular position of the clamp 356.
While the valve mechanisms 352 and 354 may be similar to that shown in Figs. 2 and 3, it is also envisioned that any suitable appropriate electronically control valving mecha-nism may be provided. Such devices are well known and conventionally available in the art. It is preferred, of course, tha-t the valve mechansim 352 and 354 be electroni-cally controlled so that with the embodiment of the metering chamber 310 of Fig. 8, both the volume of the fluid emitted by the metering chamber 310, and the rate at which the pulses of fluid are emitted, can both be controlled and varied.
Shown in Fig. 9 is yet another alternative embodimen-t - of a dual co~partment metering chamber, generally indicated at 410, con-,tructed in accordance with the present invention.
The metering chamber 410 is generally similar to the metering chamher 10 of ~ig. 1, and parts which are identical to -their correspondin~ parts in Fig. 1 are indica-tcd by similar reference numerals with 400 added thereto, wi~h only the major dif~erences in structure described in detail herein.
In the metering chamber 410, the pressure transmitting member 416 has provided approximately at its center an 30 enlarged bulbous mass 458. The mass 458 has embedded within i-t a quantity of iron filings, or other small frag-ments of ferro-magnetic material. Along the exterior of the metering chal~er 410 adjacent the mid-point of the respective chamber walls 412 and 414 are provided a pair of magnets 35 460 and 462. The magnets 460 and 462 are preferably electro-magnets, which may be therefore switched on and off, but may be also perrnanent magnets which may be moved into the posi-tions shown in Fig. 9 so as to interact with the mass 458, ~ ~ 669 -JL 6 .

~nd also mo~able by some mechanical means away from the me-tering chamber 410 so as to not to effect the position of the mass 458.
In its operation, the metering chamber 410 of Fig. 9 functions as an active pumping system, as contrasted with the passive metering systems of the embodiments of Fiqs. 1-8. The metering chamber 410 includes all the advantages of the meterin~ chamber 10 of Fig. 1, with the additional ability in that it is able to actively.pump the biological fluid from the source to the receiving body wi-thout the need for the source to be under pressure. To operate the metering chamber 410, first one and then the other of the magnets 460 and 462 is utilized to act upon the mass 458 to draw the ~ass 458, and therefore the pressure transmitting member 416, toward one or the other of the chamber walls 412 and 414 alternatively. As described, this may most easily be done by constructing the magnets 460 and 462 as electro-magnets which may be then alternatively energized, but it is also envisioned that the same result could be obtai.ned by making the magnets 460 and 462 permanent magnets which are rotated or otherwise ~oved by mechanical devices adjacent to and away from the metering chamber 410. Thus the metering chamber 410 will provide the same accurately timed and equal in volume pulses of biological fluid as does the metering chamber 10 of Fig. 1, while i-t will also actively pump the fluid from t~e source to the patient without the need for the source of the fluid to be under pressureO
It is envisioned that there are two alternatives for valve means to control the tubes 418, 420, 422, and 424 of the active pumping metering chamber of Fig. 9. On alternative is to use a timed and controlled valve mechanlsm, such as is shown with the embodiments of Figs. 1-3 and Fig. 8, to open and close the appropriate inlet and outlet tubes synchron-.ously with the operation of the magnets 460 and 462 acting on the mass 458. Another alternative is to install a simple one-way check valve in each of the tubes, with the check valves oriented to allow fluid flow toward the metering chamber 410 in the inlet tubes 418 and 422 and awa~ fram the 1 ~ 6~9~6 metering cha~nber 410 in the outlet tubes 420 and 424. These simple chec]c valves would be automatically operated by the active pumping in the metering chan~er 410 and no further control of the tubes would be neccssary.
Shown in Fig. 10 is yet another alternative embodiment of a metering chamber, generally indicated at 510, con-structed in accordance with the present invention. The metering chamber 510 of Fig. 10 is generally similar to the metering chamber 210 of Fig. 7 with inclusion therein of an active pumping provision similar to that of Fig. 9. No adjusting mechanism is shown in the metering chamber 510 bu-t such a mechanism, similar to that shown at 246 in Fig. 7, could be incorporated in this embodiment if desired. The only major differences between the metering chamber 510 of Fig. 10, and the metering chamber 210 of Fig. 7, is that the pressure transmitting member 516 of the metering chamber 510 is a slug of permanently magnetized material. Furthermore, a pair of magnets 560 and 562 are provided exteriorly of the ends of the metering chamber 510. Similar to the magnets 2() 460 and 462 of Fig. 9, the magncts 560 and 562 may be electro-magne-ts which are alternatively energi~ed, or may be perma-nent magnets which are moved into and out of position. The operation of the magnets 550 and 562 causes the pressure transmitting member 516 to move first one way and then the other within the metering chamber 510 to alternatively empty and fill the two compartments 513 and 515. The metering chamber 510 is thus an alternative embodiment of an actively pumping metering chamber which provides alternative and equal volume pulses of fluid and whlch actively pumps that ~luid from -the source to the patient. It is also envisioned that a check valve arrangement, as described in connection with the embodiment of Fig. 9, may also be utilized with this embodiment, or any other active pumping embodiment.
While it is believed that the metering device of the present invention is particularly well suited for the metering of IV fluid into a patient, it should be understood that it is also easily adaptable to any other biological ~ ~6~1 6 . .

fluids, whe-the.r entexal or parenteral, wllich may need to be administered on a dosed basis into a patient or other receiving body.
It is understood that the present invention is not limited to the particular construction and arrangement of parts disclosed and illustrated herein, but embraces all such modified forms thereof as come within the scope of -the followiny claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A metering device for metering the flow of biological fluids from a source into a receiving body comprising:

a metering chamber having first and second chamber walls therein each defining one side of first and second compartments formed in the metering chamber, first and second inlet tubes connected respect-ively to the first and second compartments, a main inlet tube for conducting fluid from the source to each of the first and second inlet tubes, first and second outlet tubes connected respectively to the first and second compartments, a main outlet tube for conducting fluid from the first and second outlet tubes to the receiving body;

valve means connected to each of the inlet and outlet tubes such that fluid flow is allowed alternatively in both of the first inlet tube and the second outlet tube and in both of the second inlet tube and the first outlet tube, a movable pressure transmitting member positioned between the first and second compartments in the metering chamber, the pressure transmitting member forming a movable portion of each of the compartments and being movable bet-ween positions pressed against each of the first and second chamber walls so that the two compartments are simultaneously and alternatively filled from the source and emptied into the receiving body, the movement of the pressure transmitting member displacing an amount of fluid equal to the volume of the metering chamber in moving in either direction between the two positions so that the amount of fluid alternatively displaced from each of the two compartments is equal to the volume of the metering chamber, and timing means for controlling operation of the valve means to alternate the closing of the pair of inlet and outlet tubes for controlling the volume of biological fluid supplied to the receiv-ing body, an amount of fluid equal to the volume of the metering chamber being supplied to the receiving body with each operation of the valve means by the timing means, the total overall rate of fluid flow supplied to the receiving body thus being determined only by the volume of the metering chamber and the rate of switch-ing of the timing means.

2. A metering device as claimed in Claim 1, wherein the pressure transmitting member is formed as a flexible membrane positioned and extending between the chamber walls.

3. A metering device as claimed in either Claim 1 or Claim 2, wherein the chamber walls are complementary.

4. A metering device as claimed in Claim 1, wherein the chamber walls are formed of biologically inert inelastic material.

5. A metering device as claimed in Claim 1, wherein the pressure transmitting member is formed as a sheet of silicone elastomer.

6. A metering device as claimed in Claim 1, wherein the metering chamber is embedded in a mounting block, the mounting block having a hole formed therethrough and wherein the first inlet tube and the second outlet tube extend in the block adjacent to one side of the hole therein while the second inlet tube and the first outlet tube extend in the block adjacent to the other side of the whole therein.

7. A metering device as claimed in Claim 6, wherein the valve means includes a rod positioned so as to extend through the hole in the mounting block, the rod being alternatively pressed against one or the other side of the hole to alternatively pinch both of the first inlet tube and the second outlet tube and both of the second inlet tube and the first outlet tube closed.

8. A metering device as claimed in Claim 7, wherein the valve means further includes an over-center spring-loaded lever connected to the rod so as to press the rod against one or the other side of the hole in the block.

9. A metering device as claimed in either Claim 7 or Claim 8, wherein the valve means further includes an electrically operated actuating device connected to the lever to cause the lever to pivot the rod from one to the other side of the hole in the block.

10. A metering device as claimed in Claim 1, wherein the metering chamber is formed as a cylindrical section of tubing, the first compartment being on the interior of the chamber, and wherein the second compartment is formed by a cylindrical section of tubing received entirely within the metering chamber and sized so as to fill the interior of the metering chamber when filled with fluid.

11. A metering device as claimed in Claim 10, wherein the pressure transmitting member is a portion of the tubing of the second compartment.

12. A metering device as claimed in Claim 1, wherein the metering chamber is formed between elongated complemen-tary chamber walls with the pressure transmitting member being a flexible membrane positioned therebetween, and wherein pinching means are provided to close a portion of the metering chamber to selectively change the effective volume of metering chamber and of the compartments of the chamber.

13. A metering device as claimed in claim 1 wherein motive means are provided to actively force the pressure transmitting member between the two positions.

14. A metering device as claimed in Claim 13, wherein the motive means includes a mass of magnetic material included in the pressure transmitting member and selectively actuable magnets located outside of the metering chamber but adjacent thereto so as to be capable of acting on the mass of magnetic material in the pressure transmitting member to force the pressure transmitting member between the two positions.

15. A metering device as claimed in Claim 14, wherein the pressure transmitting member is itself a permanent magnet.

16. A metering device as claimed in Claim 14, wherein the magnets are electromagnets.

17. A metering device for metering the flow of biological fluids from a source into a receiving body comprising:

a metering chamber defined between first and second chamber walls, first and second inlet tubes connected through the first and second chamber walls respectively,

Claim 17 cont'd a main inlet tube for conducting fluid from the source to each of the first and second inlet tubes, first and second outlet tubes connected through the first and second chamber walls respectively, a main outlet tube for conducting fluid from the first and second outlet tubes to the receiving body, valve means connected to the inlet and outlet tubes such that fluid flow is allowed alternatively in both of the first inlet tube and the second outlet tube and in both of the second inlet tube and the first outlet tube, a pressure transmitting member formed as a membrane of flexible sheet material extending between the chamber walls to define first and second compartments between the first and second chamber walls respectively and the pressure transmitting member, the pressure trans-mitting member being movable between positions pressed against the first and second chamber walls to simultaneously and alternatively fill from the source and empty into the receiving body the first and second compartments, the volume of each compartment being determined by the volume of the metering chamber since when either of the compartments is filled the pressure transmitting member is pressed against the opposite chamber wall, and timing means for controlling operation of the valve means to alternate the closing of the inlet and outlet tubes for controlling the volume of biological fluid supplied to the receiving body, an amount of fluid equal to the volume of the metering chamber being supplied to the receiving body with each operation of the valve means by the timing means, the total overall rate of fluid flow supplied to the receiving body thus being determined only by the volume of the metering chamber and the rate of switching of the timing means.

18. A metering device as claimed in Claim 17, wherein the first and second chamber walls are complementary in shape.

19. A metering device as claimed in either Claim 17 or Claim 18, wherein the pressure transmitting member is formed of a silicone elastomer.

20. A method of metering and controlling the flow of biological fluid under pressure from a fluid source into a patient comprising the steps of:
electrically actuating a valve means to allow fluid flow from the fluid source into a first compartment of a metering chamber for a fixed time period which is long enough to ensure that the compartment fills with the fluid, the fluid flow into the first compartment causing a pressure transmitting member to force any fluid out of the second compartment of the metering chamber into the patient;
electrically actuating a valve means to allow fluid flow from the fluid source into the second compartment of the metering chamber for the same fixed time period, the fluid flow into the second compartment causing the pressure transmitting member to force fluid out of the first compartment into the patient; and repetitively and alternately actuating the valve means to allow such fluid flow into each of the two compartments under the control of a timing means until the desired amount of fluid is introduced into the patient, the amount of fluid being determined by the volume of the compartments and the number of operations of the timing means.

21. A method of metering and controlling the flow of a biological fluid as claimed in Claim 20, wherein the allowing of fluid flow into the first compartment is accomplished by opening valve means of an inlet tube into the first compartment and on an outlet tube from the second compartment while closing valve means on an inlet tube into the second compartment and on an outlet tube from the first compartment, and wherein the allowing of fluid flow into the second compartment is accomplished by opening valve means on the inlet tube to the second compartment and the outlet tube from the first compartment while closing valve means on the inlet tube to the first compartment and the outlet tube from the second compartment.