U.S. patent application number 11/630613 was filed with the patent office on 2009-03-05 for medical pump.
This patent application is currently assigned to Erbe Elektromedizin GMBH. Invention is credited to Martin Hagg, Ralf Kuehner, Lothar Mitzlaff, Jochen Queck.
Application Number | 20090060764 11/630613 |
Document ID | / |
Family ID | 34979089 |
Filed Date | 2009-03-05 |
United States Patent
Application |
20090060764 |
Kind Code |
A1 |
Mitzlaff; Lothar ; et
al. |
March 5, 2009 |
Medical Pump
Abstract
Medical pumps for water jet surgery are known. The invention
relates to a pump comprising at least two pistons provided with
piston rods for displacing the pistons in cylinders and for
coupling to a pump actuation device, a cylinder head for closing
the cylinders, and valve means for respectively connecting a
pressure chamber in the cylinder to at least one fluid inlet and at
least one fluid outlet. Said fluid outlet is connected to the fluid
inlet in a communicating manner by means of an adjustable pressure
regulating valve, in such a way that the pressure in the fluid
outlet can be limited to a predetermined maximum value so that
operation of the pump can be.
Inventors: |
Mitzlaff; Lothar; (Lagos,
PT) ; Kuehner; Ralf; (Stuttgart, DE) ; Hagg;
Martin; (Wannweil, DE) ; Queck; Jochen;
(Tubingen, DE) |
Correspondence
Address: |
DICKSTEIN SHAPIRO LLP
1825 EYE STREET NW
Washington
DC
20006-5403
US
|
Assignee: |
Erbe Elektromedizin GMBH
Tubingen
DE
|
Family ID: |
34979089 |
Appl. No.: |
11/630613 |
Filed: |
June 22, 2005 |
PCT Filed: |
June 22, 2005 |
PCT NO: |
PCT/EP05/06755 |
371 Date: |
December 22, 2006 |
Current U.S.
Class: |
417/460 |
Current CPC
Class: |
A61B 17/3203 20130101;
F04B 1/02 20130101; F04B 49/035 20130101; F04B 53/007 20130101 |
Class at
Publication: |
417/460 |
International
Class: |
F04B 19/02 20060101
F04B019/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2004 |
DE |
10 2004 031 673.2 |
Claims
1. Medical pump, comprising a pump actuating device; at least two
pistons with pistons rods for displacing the pistons in cylinders
defined by said pump and coupling the pistons to said a pump
actuation device; a cylinder head sealing the cylinders; valve
means that respectively connect a pressure chamber in each of the
cylinders with a fluid inlets and a fluid outlet; and an adjustable
pressure control valve is provided, in order adapted to limit the
fluid pressure in each fluid outlet to a predetermined maximum
value.
2. Medical pump according to claim 1, wherein said pressure control
valve is connected to said fluid inlet and said fluid outlet in
such a way that, when the fluid pressure exceeds said predetermined
maximum value, fluid from said fluid outlet is piped back to said
fluid inlet.
3. Medical pump according to claim 1, wherein at least one of said
valve means or said pressure control valve comprises an elastic
valve membrane (36).
4. Medical pump according to claim 1, wherein said valve means
comprise spring-loaded non-return ball valves
5. Medical pump according to claim 1, wherein said pressure control
valve comprises an actuator and is a power-controlled valve in
which said predetermined maximum value is adjustable by a
displacement force acting on said actuator.
6. Medical pump according to claim 1, wherein said pistons and said
piston rods are connected to the cylinders in a sealed manner which
maintains sterility.
7. Medical pump according to claim 1, wherein said valve means
devices are fitted at least in part in said the cylinder head.
8. Medical pump according to claim 1, wherein said cylinders are
individually connected to said cylinder head.
9. Medical pump according to claim 1, wherein said fluid outlet has
connecting devices irreversibly connecting it to a pressure
hose.
10. Medical pump according claim 1 wherein said cylinder head has
holding means that holding catches, which are attached to said the
pump actuation device.
11. Medical pump according to claim 1, comprising an accumulator
which is connected to the fluid outlet and which smoothes out
pressure fluctuations in the fluid at the fluid outlet by means of
a low pass function.
12. Medical pump according to claim 11, wherein said accumulator is
located in or is connected to said cylinder head.
13. Medical pump according to claim 1, wherein said pressure
control valve is fitted at least in part in said cylinder head.
Description
RELATED U.S. APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] The invention relates to a medical pump, in particular for
water jet surgery.
BACKGROUND OF THE INVENTION
[0005] Water jet surgery has been used for some time in liver
surgery as this organ, like no other, has tissue structures of
different firmness (parenchyma, blood vessels and bile ducts) and
the applied water jet separates the tissue being cut, yet leaves
the blood vessels and bile ducts undamaged. Naturally, a precise
control of the cutting pressure is required for this.
[0006] A further problem of water jet surgery is that the cutting
medium must be totally sterile (e.g. Ringer solution) as the liquid
comes into contact with body tissue in the closest and most
intensive way possible. Ordinary problems such as high reliability,
simplicity and economic manufacture must also be considered.
[0007] A medical pump for water jet surgery is described in U.S.
Pat. No. 6,216,573 B1, as well as DE 203 09 616 U1, which is
disposable and thus used only once. The pump efficiency as well as
its adjustment, however, are unsatisfactory.
BRIEF SUMMARY OF THE INVENTION
[0008] The invention provides a medical pump, in particular for
water jet surgery, which despite simple construction and
suitability for single use facilitates improved cutting
performance.
[0009] According to the invention a medical pump comprises at least
two pistons with piston rods for displacing the pistons in the
cylinders and for coupling to a pump actuation device, a cylinder
head for closing the cylinders in relation to the pistons, valve
means for connecting the pressure chamber with at least one fluid
outlet and at least one fluid inlet, whereby the fluid outlet
interacts with the fluid inlet via an adjustable pressure control
valve in such a way that the pressure in the fluid outlet can be
limited to a predetermined maximum value.
[0010] As the pump is operated with two piston/cylinder units, an
improved and smoothed out pump capacity can be achieved. The
construction is simple so that economic manufacture is possible.
The already improved pumping of the working fluid is further
improved by the pressure control valve as it can be smoothed out
and at the same time be adjusted to the application
requirements.
[0011] The valve means and/or the pressure control valve comprise
an elastic or elastically pressurized valve membrane. This enables
very economic manufacture and high operational safety.
[0012] The valve devices can also comprise two spring-loaded ball
check valves, which again are simple to produce.
[0013] The pressure control valve is preferably constructed as a
power driven valve in such a way that the maximum value is
adjustable by means of actuating power on a regulator of the
pressure control valve. This special form facilitates coupling of
the medical pump to the pump actuation device in an advantageous
manner, where a particular specific spatial positioning of the pump
in relation to the pump actuation device is not required. Because
the pressure adjustment is not proportional to the travel but
proportional to the force, coupling of the pressure control valve
to a regulating unit is not position-dependent (which would require
accurate adjustment of the pump), it is rather the position
independent force with which the regulator activates the pressure
control valve which is important.
[0014] The pressure control valve is preferably arranged between
fluid inlet and fluid outlet in such a way, that on exceeding the
maximum value, fluid from the fluid outlet can be directed back to
the fluid inlet. In this way the pressure can be adjusted
independently of the quantity of pumped fluid.
[0015] The pistons or pistons rods are preferably connected
securely and in a sterile way via bellows, cup seal or similar
non-slip seals to the cylinders. Germs can thus not be introduced
despite sterile working fluid and sterile transmission pipes, which
can be the case with pumps known hitherto. This danger is
particularly great as due to piston displacement in the cylinders
their back ends (in relation to the pressure chambers) are
subjected to streams of ambient air and thus cylinders can be
contaminated therewith in this area.
[0016] The valve devices and/or pressure control valve are
preferably housed in the cylinder head. This results in a simpler
setup containing fewer parts.
[0017] It is preferred that the cylinders are connected
independently to the cylinder head. This simplifies
manufacture.
[0018] The outlet preferably has fittings for irreversible
connection to a pressure hose. This avoids a faulty installation of
the pump and also non-permissible re-use of the pump.
[0019] The cylinder head preferably comprises holding devices, in
particular lugs into which the catches engage, which are attached
to the pump actuation device. No special measures are thus needed
for mounting the pump to the pump actuation device.
[0020] An accumulator is provided in a preferred embodiment and is
connected to the fluid outlet in such a way that fluid pressure
fluctuations at the fluid outlet are smoothed out due to a low pass
function. This results in a further smoothing of the cutting jet
and thus an improvement of the equipment cutting function desired.
The accumulators are preferably situated in the cylinder head or
connected therewith which simplifies the assembly of the entire
arrangement.
[0021] Embodiments of the invention will now be described by way of
example with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIGS. 1 to 3 are schematic block diagrams of different
embodiments of the medical pump arrangements according to the
invention.
[0023] FIG. 4 is an exploded view of an embodiment of the pump.
[0024] FIG. 5 is a side view of the pump shown in FIG. 4.
[0025] FIG. 6 is a section along line VI-VI in FIG. 5.
[0026] FIGS. 7 and 8 are partial sectional views through the
medical pump in the pressure control valve area in two respective
control positions.
[0027] FIG. 9 is a perspective view of a cylinder head of the
pump.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The same reference numbers will be used for the same parts
and parts with the same function.
[0029] A pump actuation device 10 is intended for the embodiment of
the invention shown in FIG. 1, which encompasses a motor control 15
for the control of two motors 11,11', which are connected via
gearing 12, 12' and clutch devices 13, 13' to the piston rods
25,25'. One operator B can operate the motor control 15 with
suitable switches (foot switch or finger switch), so that the
motors 11, 11' displace the piston rods 25, 25' and thus the
pistons 22, 22' in the cylinders 21, 21' of pump unit 20
alternately via the described train, so that the volume of the
pressure chambers 16, 16' of the pump unit 20 is alternately
enlarged and reduced.
[0030] In order to seal the pressure chambers 16, 16' and the
pistons 22, 22' in relation to the cylinders 21, 21' seals 23, 23'
are provided at the pistons 22, 22'. Moreover, the piston rods 25,
25' maintain sterility with cup seals 24, 24', which are firmly
fixed to the cylinders 21, 21' on the one hand and to the pistons
rods 25, 25' on the other. In this way germs from the ambient air,
which without these cup seals 24, 24' would settle on the internal
walls of the cylinders 21, 21' and pass through the seals 23, 23',
can neither mix with the working fluid nor find their way into the
same.
[0031] Suction valves 26, 26' as well as pressure valves 27, 27'
are connected to the pressure chambers 16, 16'. The suction valves
26, 26' are connected via a fluid inlet 6 to a reservoir 9 for the
working fluid. The pressure valves 27, 27' are connected to the
pressure hose 5 via a fluid outlet 7, which leads to an applicator
8. The pump unit 20 forms a disposable part E together with the
reservoir 9 including its contents, pressure hose 5 and applicator
8, which is disposed of after each operation, so that the entire
setup meets the highest sterility requirements possible.
[0032] A butterfly valve 14 is intended for adjustment of pressure
in this simple embodiment of the invention (which in addition to
the motor control 15) facilitates adjustment of the fluid flow by
operator B.
[0033] The embodiment of the invention shown in FIG. 2 differs from
that in FIG. 1 by virtue of the provision of a pressure control
valve 35, which with the aid of a valve membrane 36 can open and
close a connecting channel between fluid outlet 7 and fluid inlet
6. The membrane 36 is operated by an actuator 30 via a push rod 34
and a spring 33, as well as a dynamometer 31. The dynamometer 31
supplies a power proportional output signal to a controller 32, via
which an operator B can set a maximum pressure. Instead of a
separate dynamometer 31 the operating current of the actuator 30
can also be measured which is also power proportional.
[0034] This arrangement means that the fluid pressure can be
accurately adjusted at the applicator 8. Moreover, pressure
fluctuations resulting from piston operation are smoothed out by
the control valve 35. The pressure control valve 35 owing to its
construction operates with the membrane pressurised by fluid, in a
power-controlled and not a travel-controlled manner. No pressure
adjustment error can therefore occur even with dimension tolerances
during coupling of the pump unit 20 to the pump actuation device
10, as it is not the geometric dimensions (travel) which are
important, but the power with which the pressure control valve 35
is operated.
[0035] The embodiment shown in FIG. 3 differs from the previously
shown embodiments by virtue of the provision of an accumulator 40,
which comprises a cylinder 44 containing a piston 42 sealed by a
seal 43, which is pressurized by a spring 41. A chamber situated
above the piston is connected to the fluid outlet, so that with
increasing pressure at the fluid outlet 7 the spring 41 is
compressed and with decreasing pressure the spring 41 drives the
piston 42. In this way the pressure directed to the applicator 8 is
smoothed out due to its low pass function. This accumulator 40 is
arranged in a cylinder head 29 which seals the cylinders 21, 21'.
It is also possible to combine the variants show here. In
particular the pressure control valve 35 can be combined with the
accumulator 40.
[0036] FIG. 4 shows a constructive embodiment of the pump device 20
in an exploded view. In this embodiment the pressure and suction
valves 26/27 comprise balls 19, which are pressed onto the valve
seats via springs 18 (not visible in the illustration), in an
arrangement that is known in principle.
[0037] The cylinder head 29 has two sections to which the cylinders
21, 21' are coupled, whereby the valves sit between the cylinders
21, 21' and the cylinder head 29.
[0038] It can further be seen from FIG. 4, that the piston rods 25,
25' have coupling projections 17, 17' at their distal ends which
serve to create mechanical connections with the coupling systems
13, 13'.
[0039] The pistons in this embodiment of the invention are formed
by the proximal ends of the piston rods 25, 25' fitted with caps
28, which simultaneously hold seals 23, 23' firmly on the piston
rods 25, 25'.
[0040] The pressure hose 5 is fastened irreversibly to the cylinder
head 29 via a connecting piece 37, a crimping piece 38 and an
internal pipe which is inserted into the pressure hose 5, whereby
after assembly of the connecting piece 37 (in a known way) in the
cylinder head 29 by means of a catch 45, the connecting piece is
held irreversibly in the cylinder head 29.
[0041] From FIGS. 5 and 6 details of the layout become clear in
particular in relation to the construction of the suction valve 26,
26' or the pressure valve 27, 27' and especially the layout of the
valve seats in the cylinder head 29 on the one hand and the
relevant allocated cylinders 21, 21' on the other.
[0042] FIGS. 7 and 8 show a section through the pressure control
valve 35, which shows that the membrane 36 can be pressed by the
push rod 34 onto a valve seat (FIG. 7 shows the open position and
FIG. 8 the closed), so that between fluid outlet 7 and fluid inlet
6, depending on the position of the membrane 36, a more or less
greater "short circuit" of the pump unit 20 is produced. As the
membrane 36 is pressurized by the fluid outlet 7, a
power-controlled valve is present.
[0043] FIG. 4 shows further construction related details of the
cylinder head 29 and the valve devices (suction valve, pressure
valve and pressure control valve) contained therein. Moreover, FIG.
9 shows the lugs, which are coupled via the pump unit 20 to the
pump actuation device 10 or they can be held firmly on the
same.
[0044] In an embodiment of the invention not shown here not only is
the pressure control valve 35 a membrane valve, but also the two
pressure valves 27, 27' or suction valves 26, 26' are designed as
membrane valves instead of the ball valves shown here. This makes
the arrangement even more economic. Finally, it is also possible to
create the pump in such a way that not only are all the valves
membrane valves but all the membranes are connected in one piece,
so that the number of components is decreased still further.
LIST OF REFERENCE NUMERALS
[0045] E Disposable part [0046] B Operator [0047] 5 Pressure hose
[0048] 6 Fluid inlet [0049] 7 Fluid outlet [0050] 8 Applicator
[0051] 9 Reservoir [0052] 10 Pump actuation device [0053] 11,11'
Motor [0054] 12,12' Gearing [0055] 13, 13' Clutch system [0056] 14
Butterfly valve [0057] 15 Motor control [0058] 16,16' Pressure
chamber [0059] 17,17' Coupling projection [0060] 18 Spring [0061]
19 Ball [0062] 20 Pump unit [0063] 21, 21' Cylinder [0064] 22, 22'
Piston [0065] 23, 23' Seal [0066] 24, 24' Cup seal [0067] 25, 25'
Piston rod [0068] 26, 26' Suction valve [0069] 27, 27' Pressure
valve [0070] 28 Cap [0071] 29 Cylinder head [0072] 30 Actuator
[0073] 31 Dynamometer [0074] 32 Controller [0075] 33 Spring [0076]
34 Push rod [0077] 35 Pressure control valve [0078] 36 Valve
membrane [0079] 37 Connecting piece [0080] 38 Crimp tube [0081] 39
Internal tube [0082] 40 Accumulator [0083] 41 Spring [0084] 42
Piston [0085] 43 Seal [0086] 44 Cylinder [0087] 45 Catch [0088] 46
Lugs
* * * * *