U.S. patent application number 10/507627 was filed with the patent office on 2007-07-19 for ambulatory infusion membrane pump.
Invention is credited to Billy Nilson.
Application Number | 20070166181 10/507627 |
Document ID | / |
Family ID | 20287253 |
Filed Date | 2007-07-19 |
United States Patent
Application |
20070166181 |
Kind Code |
A1 |
Nilson; Billy |
July 19, 2007 |
Ambulatory infusion membrane pump
Abstract
Ambulatory membrane pump intended for medical use e.g. for
infusion purposes, consisting of two main parts: 1) the basic
device with motor drive and computer, and 2) the administration
set, which is disposable. The arrangement with check valves in both
ends of the administration system safeguards that no leakage
happens when gravitational forces are acting, due to height
differences between fluid bag and needle.
Inventors: |
Nilson; Billy; (Mjolby,
SE) |
Correspondence
Address: |
VENABLE LLP
P.O. BOX 34385
WASHINGTON
DC
20043-9998
US
|
Family ID: |
20287253 |
Appl. No.: |
10/507627 |
Filed: |
March 12, 2003 |
PCT Filed: |
March 12, 2003 |
PCT NO: |
PCT/SE03/00411 |
371 Date: |
June 22, 2005 |
Current U.S.
Class: |
417/478 |
Current CPC
Class: |
A61M 5/16809 20130101;
A61M 5/162 20130101; A61M 5/14224 20130101 |
Class at
Publication: |
417/478 |
International
Class: |
F04B 43/08 20060101
F04B043/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 14, 2002 |
SE |
0200760-7 |
Claims
1. A membrane pump intended for transporting a controlled average
of volumetric flow rate of a fluid from a fluid source through an
outlet to a patient, the membrane pump comprising: a pump house
with a membrane, a needle arrangement, an inlet flexible tube
connected to as inlet of said pump house, an outlet flexible tube
connected to an outlet of said pump house, an inlet check valve
connected to an end of said inlet tube and positioned close to the
fluid source, and an outlet check valve connected to an end of said
outlet tube and positioned close to said needle arrangement.
2. The membrane dump according to claim 1, further comprising: (a)
said inlet and outlet tubes having inner diameters between 0.4 and
2 mm, (b) a box with an electric motor, wherein the pump house of
the membrane pump is adapted to be docked to the box, and (c)
electric control means including the electric motor, a gear, a
feeding screw and a piston for controlling the average volumetric
flow rate by means of a control of the forward and backward
movement of the piston.
3. The membrane pump according to claim 2, wherein: said membrane
is yieldable and dimensioned for safely back springing and thus
suction of the fluid into the pump house, a boss provided with
grooves is arranged on the center of the membrane, and said piston
provided with a yoke gripping into said grooves and thus
mechanically drives the membrane forwards and backwards.
4. The membrane pump according to claim 3, wherein the electric
motor and the gear are connected with the feeding screw and a
threaded nut in combination with the piston for accomplishing the
forward and backward movement, and wherein the piston is provided
with splines fitting into an end plate of the box and wherein the
piston is in contact with said boss of the membrane when the pump
house is mounted on the box.
5. The membrane pump according to claim 4, wherein the electric
motor has a revolution registering device connectable to a control
circuit, wherein said control circuit is provided with a display
and keys for operating said feeding screw to order a decided stroke
of the piston and said stroke being repeated until a new order is
received from the control circuit, whereby the volumetric flow
pumped with each stroke is controlled.
6. The membrane pump according to claim 5, wherein said control
circuit registers the content during a decided short time interval
of normal pumping and when the current significantly deviates, the
control circuit stops the pumping and gives a signal and an
information on the display.
7. The membrane pump according to claim 6, wherein the control
circuit is programmable with a dosage of the transporting and with
pump work time, intervals.
8. The membrane pump according to claim 7, wherein the box is
provided with a bar code reader and the control circuit being
programmed for medicines and dosages, safeguarding that right data
are programmed into the pump.
9. The membrane pump according to claim 8, wherein the box is
provided with loadable batteries driving the controls and the
electric motor.
10. The membrane pump according to claim 1, wherein the inlet check
valve has a cone, which is indented with, a cut, 0.1 to 0.5 mm
deep, in the upper part so that the valve is pervious when gaseous
fluid occurs, but tight when liquid fluid occurs.
11. The membrane pump according to claim 1, wherein the inlet check
valve has a colored valve cone and that said inlet check valve is
provided with a transparent housing, so that said colored valve
cone is easy to observe.
12. The membrane pump according to claim 10, wherein said cone of
the inlet check valve has minor lugs, which affect the cone to move
precisely in said transparent housing and that said cone has a
lower density than the fluid pumped for effectively de-air liquid
containing air or other gases.
13. The membrane pump according to claim 10, wherein said cone is
made to float on said fluid, whereby the cone and the fluid presses
air back through a seat face of the inlet valve, if air is present
in the fluid.
Description
TECHNICAL FIELD
[0001] The present invention relates to fluid injection pumps with
disposable membrane pump and tubing intended for injection of
medicines, pain relief and fluids related to nursing.
BACKGROUND OF THE INVENTION
[0002] Membrane injection pumps are used in many applications, as
ultra small plastic pumps intended for medical applications.
However, when used for portioning fluids, as medicines, with a high
degree of precision, usually other pumping methods dominate the
market. Such pumps are syringe or plunger pumps, as well as
peristaltic pumps.
[0003] Transporting fluids from a container to an injection needle
with a high degree of precision is claimed as to the dosage,
especially concerning new, potent medicines. Not intended leakage
through tubing arrangement must be safely restricted, as when a
container filled with medicine is placed above the needle, the
static pressure can generate a flow if the system is not restricted
against this.
[0004] Examples of prior art are: [0005] U.S. Pat. No. 6,261,066,
U.S. Pat. No. 6,234,992, U.S. Pat. No. 5,533,886, U.S. Pat. No.
6,203,291, WO 0028213, U.S. Pat. No. 5,478,211, U.S. Pat. No.
4,838,860, U.S. Pat. No. 5,637,093, U.S. Pat. No. 4,898,579
[0006] Previously infusion pumps for supplying fluids to patients
were usually syringe type, peristaltic type, membrane type or
plunge pumps. Many of these pumps are very sophisticated and
sometimes very complicated, as U.S. Pat. No. 5,482,438 and very
expensive for the hospitals. Others are simplified as U.S. Pat. No.
6,203,291, using an oscillating movement from semiconductors
affecting a diaphragm at resonance frequency and with diffusers as
controlling means in the inlet and outlet areas. Another invention
uses semiconductors in a micro membrane pump, as in U.S. Pat. No.
6,261,06. U.S. Pat. No. 5,368,570 is a plurality of membrane
pumps.
[0007] U.S. Pat. No. 4,898,579 is a dual chamber piston and
cylinder pump which uses a disposable cassette and with two
cylinders can achieve an almost uninterrupted fluid feeding.
However the cassette is with its arrangements of check valves a
little bit complicated, and the amount of material in the cassette
is significantly high. When initially filling up the pump,
de-airing obviously will become problematic.
[0008] Document U.S. Pat. No. 4,846,636 describes a piston pump
with a complicated construction, where it is very difficult to
de-air a pumped fluid In a controlled way. The design of this pump
requires sensors for detecting air in the fluid. The check valves
of this pump are further built-in into the pump house of the piston
pump.
[0009] In document WO 99/21596 there is disclosed an infusion pump
with check valves built-in into the pump house, whereby there are
also in this disclosure small possibilities to watch air in the
pump system. This pump has a large dead space, which means that a
substantial amount of fluid is interlocked into the pump when a
pumping operation is ended. The principle of this infusion pump is
based on a pumping mechanism using a semi-membrane and a
semi-piston.
[0010] A careful control of the pumped amount of fluid by use of
different piston stroke lengths are not possible in any of the
designs of U.S. Pat. No. 4,846,636 and WO 99/21596.
[0011] None of the preceding pumps unites disposability together
with high precision dosages, safety against leakage, material
saving and an uncomplicated concept as in our invention.
SUMMARY OF THE INVENTION
[0012] The present invention is a membrane pump consisting of two
main bodies: the computer with its housing and the administration
set. The membrane pump works distinctly with equal membrane
movements repeated as a decided position of the stroke. A
rotational electric motor with a gear is positioned in the housing,
and the outgoing shaft moves a screw in connection with a threaded
plunger rod and at the other end in connection with the membrane
tap. At the end cover on the housing the membrane pump is snapped
into an attachment consisting of a guide rail and a shoulder on the
pump house, which easily is snapped on when the pump house is in
exact position. The electrical motor has a permanent magnet and a
sensor which registrates each revolution of the motor and
communicates signals to the computer, which registers each signal
in forward respectively backward mode of the driving motor, thus
counting each revolution and registers the exact position of the
screw on the plunger rod.
[0013] With a high revolution electrical motordrive connected to a
gear the advance of the screw works in a very high degree of
precision, independent of accidental wear. Accordingly the membrane
moves with exact precision accordingly to ordered revolutions
rolled by the electrical motor, and the dosage can be controlled
with each stroke of the plunger rod.
[0014] In a system with tubes and pump, elastic effects can arise,
for instance when the pump suddenly is cut off (which happens when
the polarity reversal activates for intended reversal of the
plunger rod). When the pressure leaves the system, elastic effects
arise; the volume of the system decreases. In order to prevent
unintended through flow in the system according to such elastic
effects, check valves are positioned in each end of the tubing; the
inflow check valve close to the fluid container and the outflow
check valve close to the needle arrangement.
[0015] Visual control of the pump function occurs with transparent
valve housing at the inflow check valve with a colored cone
indicating the working of the pump and visible at a distance of at
least some meters.
[0016] The-to-and fro movement of the pump is driven by an electric
motor in connection with a screw-driven feed. Making the pitch
optimal, the feed becomes very accurate; e.g. when back-feeding
through reversing of the electric motor by reverse polarity, it is
very important that the movement is under strict control and not
too fast, when gas otherwise could become extricated out of the
fluid (cavitation). A processor is used to control the motor drive.
The processor has a control puls circuit which reverses the motor
drive by reverse polarity. The processor registers the working
speed and controls the ordered revolutions and when exact feeding
distance of the piston is achieved. The movement of the piston and
as well pumped quantity is thus controlled in both directions with
high degree of precision.
[0017] The processor has a box with a key set and a display
intended for controlling the dosage and watching different
functions as for the safety. The box also has rechargeable
batteries. A patient needing fluid, drugs or pain killers by
infusion, can carry the complete pump set conveniently and freely
move him without handling a stand, used for the drip chamber. Our
pump does not need the static pressure from the height with which
the fluid container is held by the stand. The pump generates this
pressure by pumping. Thus it is suitable to place the fluid
container where it is convenient.
[0018] Instead of counting the drips in the drip chamber and
throttling the tubing, you just order right dosage on display by
using the keys. If you want to watch the pump working, you look at
the transparent check valve house close to the fluid container and
at the pulsating, abovementioned cone. A more advanced model you
order the dosage with a bar code and a bar code reader.
[0019] When ambulance transports are acquired, as by accidents or
transporting patients, our device is even handier because of
independence of a stand. The device can also be used positioned on
the side of a patient in bed.
[0020] An infusion pump must be reliable and stop working, if
divergence from normal working happens, e.g. if the fluid
encounters higher or lower resistance and the pump thus meets
occlusion or very low pressure e.g. when air is in the system.
Those circumstances must be readable and the pump must stop if not
allowed deviations happen. If such deviations happen, variations of
the motor current is watched by the control system and as the
electric motor drive is pulse driven, the relations between pulses,
current and revolution is programmed in the control system, which
signals and stops the motor drive within certain limits. The
display writes which kind of deviation happened. Pressure sensors
are not necessary to use to watch the correct working of the
pump.
[0021] If gases or air are present in the tube or pump regions, the
inlet check valve has measures for de-airing the system and press
the air back to the liquid container. In a preferred achievement
the cone of the check valve is hollow and floats on the liquid
where-by it presses the air back through the seat face. The last
amount of air leaks back to the liquid container by a slit on the
cone, which slit is wide enough for gaseous fluids, but to narrow
for liquids to pass. The system is de-aired. When larger amounts of
air is present, as with glass containers, an outlet with an air
filter is arranged in the housing of the inlet check valve.
[0022] The precision of the dosage of the membrane pump is not
restricted because of small dimensions, which precision becomes
extremely high compared to e.g. a peristaltic pump, which type is
most frequently used with ambulatory pumps. The pump house and the
details of the administration set is in a preferred accomplishment
made of as drug certified thermo plastic, produced with precision
in many units.
[0023] The administration set together with the liquid (medicine)
container is disposable, as with the present drip chamber. When the
liquid is emptied, the administration set is disposed of, and a new
set is in use, when next batch is inserted. The liquid container
usually is collapsible, but a stiff one as made of glass is also
used and are united with the administration set in the same way as
with drip chambers.
[0024] All types of fluids are possible to introduce into the
patient, frequently intravenously or subcutaneously, but also in
body openings or against the body, the skin or mucous membranes.
With a bar code system you can programme the control unit so as to
introduce the right kind and amount of drug. The membrane pump has
a wide use: providing drugs, pain killers, nutrition solution or
liquid.
[0025] The invention has many other applications, other than drugs.
The pump is useful as a distributor of chemical-technical fluids
and pastes if in right dimensions and the same design. The same
material, injection molded plastic, which is recyclable, is
used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a side-sectional view of the embodiment with
insert mouthpiece for the liquid container, inlet check valve,
inlet tube, membrane pump with box and feed screw with electric
motor, outlet tube with attachment to the needle and needle.
[0027] FIG. 2 is the outlet check valve, needle attachment and
needle.
[0028] FIG. 3 is the pump house with membrane, inlet and
outlet.
[0029] FIG. 4 is an assembly of the device box and the
administration set.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0030] The exemplary embodiment of the membrane pump of the present
invention, indicated generally as the pump house 2 in FIG. 1 with
the membrane 1 and connected to an inlet tube 18 and outlet tube 5,
with inlet check valve 14 and outlet check valve 16, and an
attachment to the injection needle 8. The liquid container is
penetrated by the insert mouthpiece 15 which is connected to the
inlet check valve house 14 and with a cone 12, which floats,
movable longitudinally in the house 14. The air filter 38 is
connected to the inlet tube 15. The device box 19 is schematic
drawn and contains an electric motor 36 with gear box 35 and a
screw 11 which when rotated moves the threaded piston 9
longitudinally and the elongation of the piston 13 which presses
the membrane inwards and lets the membrane 1 free for recoiling,
whereas the membrane pump is filled with liquid. The elongation 13
of the piston 9 has splines 21 which fit in corresponding tapping
in the gablesocket 20 in the device box 19 and locks the piston
from rotation when the screw rotates.
[0031] The check valve with housing 16 in FIG. 2, with a perforated
disk 32 with a nib 31 in the center, on which the check valve
membrane 33 is clamped up. By making different thicknesses of the
membrane 33, and different preloads to the seat, you can control at
which pressure the check valve membrane 33 will open, which is
important so as not to leak when a high static pressure arises from
a high positioned liquid container.
[0032] In FIG. 3 is shown details in the pump house 2 with a
weldable attachment 4 of the membrane 1 to a part 3 of the pump
house 2. The outlet tube 6 is welded to the outlet 5 of the pump.
The circular flanges 7 are intended to increase the strength of the
removable attachment to the device box 19.
[0033] The membrane pump system is shown in FIG.4 with the device
box 19 and the administration set 40. The device box 19 consists of
a display 26, keys 24, a rapid attachment 22 of the pump house 2, a
body 25 to the liquid container 27, here shown as a collapsible
container. The administration set 40 has a hold 29 intended for
attaching and stop against the grip 22, and in the upper part a
penetrating inlet 15, a check valve cone 12, a tube 18, a pump 2
and an outlet tube 6 down to the outlet check valve 16 and
injection needle 8.
* * * * *