Note: Descriptions are shown in the official language in which they were submitted.
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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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.
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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
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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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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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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
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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
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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.
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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
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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-
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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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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 '
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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,
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~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
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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
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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.
