Dispensing – With discharge assistant – Fluid pressure
Reexamination Certificate
1999-04-15
2001-03-20
Shaver, Kevin (Department: 3754)
Dispensing
With discharge assistant
Fluid pressure
Reexamination Certificate
active
06202898
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for supplying medical instruments with a fluid, in particular a rinsing fluid, which is located in a container which can be set under pressure and into which two cannulas of a differing length may be inserted, wherein a short cannula, via a gas conduit and a release valve, is connectable to a pressurised gas source in order to impinge the container above the fluid level with pressurised gas, whilst the other longer cannula is connectable to a fluid conduit leading to the instrument and protrudes into the fluid located in the container and wherein the fluid flow to the instrument is interruptable with a blocking element and the pressurised gas supply to the container is interruptable with the release valve.
The delivery of fluid such as for example sterilised salt solution to the instrument, is introduced in the manner that a release valve is actuated via a foot switch and then pressurised gas from the pressurised gas source via the release valve impinges the fluid level of the fluid located in the container. The fluid conduit may be blocked or released via a blocking element. If the blocking element is in the release position the fluid on account of the gas pressure acting on it flows across the blocking element to the instrument, which for example comprise optics whose distal lens or distal window, with the fluid exiting from a nozzle, is rinsed free of impurities such as secretion, smoke particles and likewise, at certain time intervals, in order to offer the operator a good viewing through the optics. In order to interrupt the rinsing procedure it is not sufficient to interrupt the pressure supply from the pressurised air source, since the pressure in the container on account of the stored gas volume only sinks slowly and thus the rinsing would continue for a while.
The blocking element is mostly a tubing squeezer into which as a fluid conduit there is applied a flexible tubing, which e.g. is squeezed or released via an electromagnetically actuated pluger, wherein this together with the release valve may be controlled in its function by way of the foot switch.
A disadvantage of these known devices is that several device parts are to be handled and operated differently and separately, such as the connection of the pressurised gas conduit to the pressure source across the release valve to the shorter cannula, furthermore the connection of the fluid conduit to the longer cannula, the insertion of the fluid conduit into the blocking element and the connection to the medical instrument. Furthermore firstly the shorter cannula is to be inserted through a container closure and to be positioned above the fluid level. Subsequently or previously the longer cannula is to be handled similarly but this must be incorporated into the container such that it submerses adequately deeply into the fluid. With all these quite complicated activities also confusions of parts when making the respective connections are not to be ruled out so that there exists a considerable potential risk of error.
BRIEF SUMMARY OF THE INVENTION
It is the object of the invention to considerably simplify the application of such a device in order by way of this to rule out possible sources of errors with respect to the handling and functioning with a high security. Furthermore the device is to be manufacturable simply and cheaply.
The solution of the object lies in the fact that the cannulas, the blocking element and a control valve are grouped together into a constructional unit on which there is located one connection for the gas conduit and a further connection for the fluid conduit. By way of this a one-piece construction of the device is given, with which it is no longer necessary to have to manipulate the cannulas individually, and with whose connections the conduits may be simply connected. The blocking of the gas supply is effected in this case directly in the constructional unit by the control valve, wherein the gas supply conduit is bled.
Furthermore it is provided that the connections of the tubings are formed differently so that a connection confusion of the gas and fluid conduits formed correspondingly differently may no longer occur. The two cannulas are grouped together such that the longer cannula is surrounded at a distance by the shorter cannula coaxially and whilst forming a pressurised gas channel.
The shorter cannula at its end directed to the fluid level is provided with openings through which the pressurised gas may flow into the inside of the container in order to impinge the fluid level with pressure. The length of the shorter cannula is matched such that this ends above the fluid level, whilst the length of the other cannula is submersed into the fluid to a predetermined degree. Both cannulas are rigidly connected to one another as parts of the constructional unit so that compellingly they may only be inserted commonly into the container and with this assume the correct position with respect to insertion depth.
Furthermore the control valve and the blocking element are grouped together as a common valve and integrated into the constructional unit. This valve consists of a valve housing which axially movably accommodates a valve slider which seals on the circumference. The valve slider can be moved out of an initial position into an operating position, wherein the initial position is assumed by the force of a spring. The operating position is achieved by the pressure force which results from the gas pressure and the pressure-effective end face of the valve slider, which is distant to the spring side.
The valve slider comprises valve control edges for the pressurised gas as well as valve control edges for the fluid which in each case correspond to control openings incorporated into the housing in the operating position.
In the initial position by way of the position of the valve slider the pressurised gas conduit just as the fluid conduit are blocked from the container space towards the medical instrument.
In the operating position the valve slider releases the further conduit of the pressurised gas from the gas conduit, via the channel formed between the cannulas, by which means the gas pressure acts on the fluid level. At the same time the valve slider however also releases the transport of the fluid via the longer cannula into the fluid conduit towards the medical instrument. If the release valve e.g. operable by foot, is formed between the pressurised gas source and the constructional unit according to the invention, as a 3/2 valve, the gas conduit between the release valve and the constructional unit is bled whilst the container continues to be under pressure.
In another formation the valve slider may be so formed on its side distant to the spring that this side for example accommodates an elastomer seal which cooperates with a valve seat which is part of the pressurised gas valve. In the initial position the elastomer seal by way of the force of the spring is sealingly pressed against the valve seat and thus the pressurized gas supply towards the container is blocked.
Furthermore it is possible to realise the backflow of the gas out of the container by way of an integrated check valve instead of by way of the valve slider. The check valve with this is located between the gas conduit and the cannula in the valve housing so that preceding from the pressurised gas source with an open check valve a free flow for the pressurised gas is given. The opposite flow direction is blocked by the check function. With such a connecting arrangement then the check valve ensures that the container space above the fluid level is not then bled. Because the valve slider after bleeding the gas conduit is brought into the initial position by the force of the spring, also the fluid flow through the valve slider is immediately blocked. With the initiation of a further rinsing procedure thus the container space above the fluid level need not be filled again with pressurised gas. This permits a rapid start of the rinsing procedure after activation of t
Akin Gump Strauss Hauer & Feld L.L.P.
Deal David
Richard Wolf GmbH
Shaver Kevin
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