WO2003075992A1

WO2003075992A1 - Water trap

Info

Publication number: WO2003075992A1
Application number: PCT/EP2003/002065
Authority: WO
Inventors: Uwe Becker; Rudolph Hipp; Georg Lohmeier
Original assignee: Müfa Ag
Priority date: 2002-02-28
Filing date: 2003-02-28
Publication date: 2003-09-18
Also published as: DE10211325A1; AU2003215614A1; AU2003218672A1

Abstract

The invention relates to a water trap (1), preferably for dehumidifying respiratory gases, in which a quantity of liquid (7) that has been separated from a gas is trapped in a collection container (2) and can be drained by means of a controllable outlet device (8). Drainage can be triggered in particular by an electric signal or by the hydrostatic pressure in the collection container (2).

Description

Water falls

The present invention relates to a water trap, primarily for separating liquids from breathing gases, according to the preamble of claim 1.

Water traps are known from practice, with the aid of which liquid, in particular water, can preferably be separated from gas streams. This can be necessary for the measurements to be carried out on the gas flows or also for the protection of measuring instruments or devices. Water traps are particularly used in ventilation technology in medical technology, with breathing gases removing the water and any mucus that may be present in order to protect the connected ventilation devices from moisture.

The gases to be freed from the liquid are usually used for measurements in which various physical or chemical properties are measured. These measurements can be made permanently or in certain time periods. In order for the measurements to produce a reliable measured value, a steady or quasi-steady state of operation of the gas flow is preferably sought in practice. Only those measurement signals that are recorded when the operating state is as stationary as possible are suitable for further processing and thus for the control of a respiratory system.

The liquid, which is usually water, is usually separated out via one or more membranes while the gas flows through them. The membranes are designed so that moisture in droplet or gaseous form cannot penetrate these membranes. The liquid retained in this way can then be removed separately. A certain ambient pressure in the area of the membranes is required so that the membranes can perform their separation function satisfactorily. For this reason, it makes sense to arrange a closed container around the membranes, with which the environmental conditions required for the deposition, in particular the pressure, can be set. According to the prior art, manual emptying of this container is then required. A direct release of the water deposited on the membranes into the environment is not possible with water traps according to the prior art.

In addition, if the separating membranes come into direct contact with the ambient air, there is often the problem that the gas stream is mixed with the ambient air or that its concentration or other properties change. This can also lead to incorrect measurement results, which can have a negative impact on the treatment of the patient.

The water is thus collected in the water traps known from the prior art in a container which usually surrounds the membranes directly. The separated water then drips down from the membranes and collects in the container.

The container that fills in this way must be emptied from time to time. In medical technology in particular, this is currently done by hand, so that the treatment personnel must constantly monitor the water trap, which is built into the expiratory gas stream of an artificial respiration, for example, and operate or empty it if necessary. In the prior art, the staff either removes the water trap or the container of the water trap in order to then empty the container directly or by suitable measures.

The manual emptying of the water trap causes a disturbance in the operating state of the gas flow, in particular the pressure conditions in the water trap. If By draining the water, the pressure in the water trap changes at least temporarily, the measured values of the gas flow recorded during this time are mostly unsuitable for further processing. This can disadvantageously lead to system malfunctions and possibly endanger the ventilated patient.

The object of the invention is therefore to present a water trap, the emptying of which can be triggered by a predefinable event, and which thus enables user-friendly, safe and inexpensive moisture separation and in particular improves the treatment of respiratory patients.

The object is achieved by a water trap according to claim 1.

The invention is based on the knowledge that the emptying of a water trap can advantageously be linked to suitable emptying times. In particular, the emptying can be triggered as a function of measurement processes or also of operating conditions in the water trap. This has the advantage that, on the one hand, no operating personnel is required for emptying the water trap, but on the other hand the emptying can also be selected such that a disturbance of measured variables caused by the emptying is irrelevant at the time of emptying.

In a simplest embodiment of the invention, a water trap with at least one liquid separating element is provided. This is preferably a membrane, and any other component suitable for separating liquids can also be used. A gas to be dried is passed over or through this membrane, with liquid contained in the gas being deposited on the membrane. A liquid collection container is provided below the membrane and is designed to hold the amount of liquid separated from the membrane. This liquid collecting container has an outlet collecting opening through which the liquid is dispensed or removed from the container can. At the outlet opening there is an outlet device through which the liquid can flow.

In the simplest case, the outlet device is a controllable valve. The valve can be controlled in such a way that it opens or closes - possibly also in a controllable manner - and thus clears or blocks the emptying path for the liquid. This means that the valve can be controlled for automatic emptying depending on certain events without the emptying having to be actively carried out manually.

The type of control of the outlet device can take place depending on the design or type of the available control signals. In an advantageous embodiment, the outlet device can be controlled electrically. This could be a solenoid valve, for example, which is caused to open or close by applying a suitable voltage. This voltage or a control signal producing the voltage can be applied by a measuring device, by a separate control unit or directly by a medical device, such as a respirator. Such a valve can advantageously be controlled relatively easily, without the need for further mechanical or hydraulic-pneumatic components.

In a further advantageous embodiment, the outlet device can be actuated pneumatically. In this way, the outlet device, which could then be, for example, a simple compressed air operated valve, can advantageously be fed from an existing compressed air network. In this case, the activation could again take place via a suitable measuring device or a separate control unit or directly from a respirator, in which case the compressed air required to act on the outlet device would be dosed or regulated accordingly. The use of such pneumatic outlet devices advantageously makes the water trap independent of electrical energy. In a further advantageous embodiment of the invention, the outlet device can be controlled hydraulically. Since the fluid used for hydraulic control is preferably not very compressible, the outlet device can be controlled very precisely. Furthermore, the water trap can be operated relatively quietly, which is particularly beneficial for a treated patient. The metering or application of the controlling fluid can preferably take place again via a separate control unit or also directly via a measuring device or a respirator, which, for example, converts electrical signals into corresponding pressures of the fluid controlling the outlet device or into a movement of this fluid.

In a further advantageous embodiment of the invention, the outlet device can be controlled predominantly mechanically or electromechanically. The device can be opened or locked via an actuating mechanism in order to release or shut off the container contents. The mechanism can be at least partially designed as a movable and driven component of a control unit or a respirator and can act on the device via a suitable transmission or translation, for example to actuate a slide on it, to change a cross-section or to otherwise empty it cause. This has the advantage that, for example, mobile water traps themselves remain insensitive to vibrations and harsh operating conditions, and in particular can work independently of control electronics which are susceptible to malfunction.

The mechanical loading of the outlet device can take place via a motor or another, for example mechanical, hydraulic, electrical or pneumatic, actuator and can act on the device, for example, via a lever or transmission mechanism.

In a particularly advantageous embodiment of the invention, the outlet device can be controlled by the hydrostatic pressure of the collected liquid. There is a coupling between the liquid collection container and the outlet direction chosen so that the hydrostatic pressure of the liquid collected in the collection container can act on the outlet device such that it empties at least part of the liquid from the collection container. The coupling can take place directly or using a suitable mechanical or other translation mechanism. In particular, a purely mechanical or non-electrical actuation of the valve is conceivable. However, the hydrostatic pressure can also be detected by a suitable sensor and used as a triggering criterion for an electrical emptying signal to the valve. This signal can be used in addition or alternatively for further processing in suitable measuring devices, control units or in particular respirators, in order to, for. B. to document the fill level during a ventilation process.

Such a hydrostatic control of the outlet device has the advantage that the water trap automatically triggers an emptying process when a certain filling quantity is reached. In this case, the trigger originally does not come from a measuring device, a control unit or, for example, a respirator, but from an operating state that arises within the water trap.

The outlet device can in particular be designed such that when a certain hydrostatic pressure, which corresponds to a fill level, is reached, the outlet device opens and remains open until the hydrostatic pressure falls below a predeterminable minimum value. In this way, it can advantageously be achieved that the container is completely emptied when the filling level which triggers emptying is reached before the outlet device closes again.

In a further advantageous embodiment of the invention, a fill level detector is provided on the water trap. The fill level detector outputs at least one suitable signal as a function of the fill level or the amount of liquid in the collecting container or when a predeterminable maximum fill level is reached. This signal can be converted into a control unit, if necessary Control of the outlet device can be used. This can preferably be an electrical signal, but in principle the output of different types of signals by the level detector is also conceivable.

As an alternative or in addition to the signal-based control, the purely mechanical control of the outlet device by the fill level detector is also conceivable. For example, a float raised by the liquid can transmit movement to the device to open or close it.

A water trap designed with a fill level detector has the advantage that emptying of the collecting container can be triggered as a function of a predeterminable fill level. This essentially corresponds to the triggering principle via the hydrostatic pressure, which is triggered via the fill level. The fill level detector can be triggered independently of the pressure and also detect different fill levels and output the signals associated with the fill levels both for triggering the outlet device and for further processing in corresponding evaluation units, control units or, for example, also a respirator.

The water trap is particularly advantageous if the outlet device can be controlled simultaneously according to several of the aforementioned principles. In particular, it can thus be controllable electrically and / or pneumatically and / or hydraulically and / or mechanically and / or via the hydrostatic pressure. This advantageously enables emptying of the collecting container depending on different criteria. For example, an emptying process can be triggered either by the hydrostatic pressure of the contents of the collecting container or also by an electrical signal transmitted by a measuring device or a control unit.

It is particularly conceivable that the water trap is emptied via an electrical signal at predetermined time intervals. A control unit controls the outlet device for emptying at these corresponding time intervals. However, should the contents of the container increase above a predeterminable maximum value between the intended times, the emptying can also be triggered by the now sufficiently high hydrostatic pressure inside the container, regardless of the next time-dependent control signal that has not yet occurred.

A similar constellation is conceivable for the case in which the hydrostatic pressure of the container contents should basically be used as a triggering criterion for emptying. Should a malfunction occur, for example in the transmission mechanism of this hydrostatic pressure, an electrical signal triggering the emptying could be generated, for example, via the fill level detector in order to prevent the container from overfilling.

The simultaneous controllability of the outlet device according to different principles thus advantageously enables the redundant monitoring of the container contents or the triggering of the container emptying according to various, mutually independent criteria. This simplifies handling and increases safety for a patient and for the ventilators used.

Furthermore, an evaporator is advantageously connected to the water trap, via which the water emptied from the container evaporates and can be released into the ambient air. In this way, the specific disposal of the water in a larger collecting container downstream of the water trap is superfluous, and at the same time the air in the vicinity of the evaporator is enriched with water.

The outlet device can advantageously be controlled in such a way that a measured value from the gas stream that is detected during the emptying process does not lead to malfunctions or incorrect evaluations. In particular, the water trap can be emptied whenever a sensor used for the analysis of the gas flow has to be calibrated. During a calibration, there is no measurement or evaluation of the sample stream taken from the breathing gas, since, for example, a switch is made to a reference gas. This is similar for many other measurements. During this period, no treatment-relevant data can be recorded or processed anyway. Since incorrect measurements in the gas flow can occur when emptying the water trap, as shown above, the calibration period is also suitable for emptying the water trap, since the falsified measurement values in the gas flow are not taken into account anyway.

The ventilator or the control unit, which carries out the calibration of certain sensors, can thus control the outlet device of the water trap for emptying the collecting container during some or all calibration processes while such a calibration process is taking place. In this way, the water trap can be emptied without an additional interruption of the measurements or even the treatment.

In a further advantageous embodiment of the invention, the outlet device is also designed to emit at least one signal to a control unit or in particular a respirator. This signal can be used to inform the connected unit, for example, about the operating state of the outlet device or, in particular, about a currently emptying process.

This is of interest, among other things, when the emptying of the container is triggered by the hydrostatic pressure of the liquid collected. Since this emptying is always triggered independently of an external emptying signal when the fill level has reached a certain minimum level, the measurement values then incorrectly recorded during the emptying process can be suppressed on the basis of the signal then transmitted by the outlet device. In this way, the water trap can emit a signal to a control unit or a respirator at the beginning of an emptying, which - in reverse consequence of the above - tem - for example, the calibration of various sensors can be activated while the emptying process is running. In particular, the "water trap full" signal can be used alone or as an additional signal to initiate a calibration process.

Basically, the "emptying" event and the "calibration" event, depending on which occurs first, can be used to trigger the other event in order to advantageously save time and simplify use.

Further advantageous embodiments of the invention result from the subclaims.

A particularly advantageous embodiment of the invention is explained below using a description of the figures. The only Fig. 1 shows a schematic side view of a water trap according to the invention.

As can be seen in FIG. 1, a water trap 1 has a liquid collecting container 2. In the present example, the liquid collection container 2 has the shape of an upright cuboid. A liquid filter membrane 4 is arranged in an upper region of the liquid collecting container 2. A liquid can flow through the liquid filter membrane 4, the membrane 4 separating liquid from the gas during the flow.

The gas, which should preferably be an expiratory gas, is fed to the membrane on a path E and discharged via a path A. Essentially, the gas is therefore conducted into and out of the liquid collection container 2, the membrane 4 arranged within the collection container 2 performing a liquid separation. A quantity of liquid 7 that has already accumulated is indicated in a lower region of the collecting container 2. The amount of liquid 7 rests essentially on a lower boundary wall 6 of the cuboid opposite the upper section of the collecting container 2.

Provided underneath the boundary wall 6 is a valve designed as an outlet device 8, which is fluid dynamically connected to the quantity of liquid 7 through the boundary wall 6. The valve 8 can be controlled in such a way that it discharges the amount of liquid 7 from the collecting container 2 in an emptying direction L or encloses it in the collecting container 2 by blocking this path.

The valve 8 is connected on the one hand to a control unit 12 which can control the valve 8 for opening or closing. In addition, the valve 8 can advantageously also be actuated via an opening device 15. This opening device 15 actuates the valve 8 as a function of the hydrostatic pressure which the amount of liquid 7 exerts on the boundary wall 6 or on a pressure element formed in the boundary wall 6, which is part of the opening device 15. The pressure element causes the actuation of the valve 8 when a predeterminable pressure is exceeded via a coupling mechanism in the opening device 15. In this way, the valve 8 can thus be controlled by a control unit 12 on the one hand via the hydrostatic pressure of the liquid quantity 7 and also via a suitable control signal.

A fill level detector 10 is formed in the region of a side wall of the liquid collection container 2. The fill level detector 10 detects the fill level of the liquid quantity 7 in the collecting container 2 and forms a corresponding fill level signal which is transmitted to the control unit 12. If a limit value which can be predetermined in the fill level detector 10 or the control unit 12 or a respirator (not shown) is exceeded, the fill level signal can trigger the valve 8 to open and thus to empty the collecting container 2. The control unit 12 can exchange signals for the transmission of an operating state, a fill level, an emptying signal or physical parameters via a signal connection with a respirator (not shown here).

Claims

claims

1. water trap (1), preferably for dehumidifying breathing gases,

a) with at least one liquid separating element (4), in particular a membrane, and b) with a liquid collecting container (2) for receiving a quantity of liquid (7) separated from the at least one membrane (4), and c) with an outlet device (8) for Emptying the amount of liquid (7) from the liquid collecting container (2),

characterized in that

d) the outlet device (8) can be controlled for opening and / or closing.

2. Water trap according to claim 1, characterized in that the outlet device (8) is electrically controllable.

3. Water trap according to one of the preceding claims, characterized in that the outlet device (8) is designed for pneumatic control, the control preferably being effected via a control unit (12) acting pneumatically on the outlet device (8).

4. Water trap according to one of the preceding claims, characterized in that the outlet device (8) for mechanical control is formed, the control preferably taking place via a control unit (12) which acts mechanically on the outlet device (8).

5. Water trap according to one of the preceding claims, characterized in that the outlet device (8) is designed for hydraulic control, the control preferably being effected via a control unit (12) which acts hydraulically on the outlet device (8).

6. Water trap according to one of the preceding claims, characterized in that at least one level detector (10) is provided for controlling the outlet device (8).

7. Water trap according to one of the preceding claims, characterized in that the outlet device (8) can be controlled by the hydrostatic pressure of the collected liquid (7).

8. Water trap according to one of the preceding claims, characterized in that an evaporator can be connected to which the emptied amount of liquid (7) is fed to the environment for evaporation.