GB2228684A

GB2228684A - Recirculatory respiratory protective apparatus

Info

Publication number: GB2228684A
Application number: GB8928508A
Authority: GB
Inventors: Adalbert Pasternack
Original assignee: Draegerwerk AG and Co KGaA
Current assignee: Draegerwerk AG and Co KGaA
Priority date: 1989-01-24
Filing date: 1989-12-18
Publication date: 1990-09-05
Also published as: DE3901919A1; ZA90380B; GB8928508D0; AU4863790A; FR2641976A1

Description

Circulatory reaRiratory Drotective aRRaratus This invention relates to a

circulatory respiratory protective apparatus comprising a respiratory bag which is connected to an oxygen supply valve controlled by the respiratory activity of the wearer of the apparatus when. in use. the oxygen supply valve is connected to an oxygen source.

Oxygen supply valves controlled by respiratory activity are known from, for example, DE-C-729638. In this case, the respiratory bag is connected to a membrane valve and, when the pressure in the respiratory bag is low, the membrane valve closes an electrical contact device and opens, against spring action, the oxygen supply valve. so that oxygen flows is from an oxygen source into the respiratory bag.

In DE-B-1573124, there is disclosed a respiratory gas supply device with an electrically actuated oxygen supply valve, and which has a pressure transformer which, on one hand, is actuated by the pressure of a reference pressure source and, on the other hand, by the pressure in the mask space, and which generates a signal corresponding to the measured pressure difference, which signal controls the oxygen supply valve such that the amount of oxygen released by the valve into the mask space is approximately proportional to the reduction of pressure in the mas k space relative to the reference pressure. In this way, the amount of respiratory gas supplied should be adapted to the requirement of the user in a sensitive manner.

The object of the present invention is to improve an apparatus of the type described so that. without a low pressure in the respiratory bag and in the lungs (and thus without additional load upon the wearer of the apparatus), a favourable adaption of the oxygen supply to the oxygen requirement necessary in the working or resting state is possible.

The solution of this object is achieved in that, for controlling the oxygen supply valve, a sensor is provided outside the respiratory gas guidance. The previously known apparatus are controlled by pressure sensors which establish. directly or indirectly, the pressure in the respiratory gas guidance or in the respiratory gas circuitr and regulate the oxygen supply according to these pressure values. In the present invention, the oxygen supply valve is controlled by the sensor independently of the respiratory gas guidance, in particular by a movement sensor or by an oxygen partial pressure measuring sensor able to be placed on the skin surface.

According to the present invention. there is provided a circulatory respiratory protective apparatus, comprising a respiratory bag which is connected to an oxygen supply valve controlled by the respiratory activity of the wearer of the apparatus, wherein, for controlling the oxygen supply valve. a sensor is provided outside of the respiratory circuit of the apparatus.

Thus, by the invention, a favourable adaption of the oxygen supply to the working or resting state of the wearer of the apparatus, is achieved.

Particularly in the case of the use of a movement sensor which senses movement of the thorax for controlling the oxygen supply, it can be advantageous to provide a basic amount of oxygen by a device for permanent supply and to use the movement sensor for controlling increased demand. In this way, the limited oxygen requirement for the resting state is provided by the permanent supply and only the increased requirement is then controlled by way of the movement sensor which senses the thorax movement. The level of the permanent supply is advantageously about 0.5 litres/minute. This amount corresponds to minimal thorax expansion, which is generally hard to detect by movement sensors. If under load, an increased oxygen consumption occurs, an advantageous detection is possible by way of movement of the thorax, by the movement sensor.

This movement sensor can advantageous comprise at least one strain guage, puch as a wire strain gauge, arranged in association with a thorax belt or body support.

It is advantageous to generate the control signal from several thorax movements occurring one-after the other. In this case, a device for storing electrical signals derived from the respiratory movement is advantageous provided, and, with the aid of a window comparator, the control signal, for activating the oxygen supply valve. is generated from a number of signals of the respiratory movement.

In an advantageous embodiment. the sensor can be connected to an amplifier which is connected by way of a transmitter to the oxygen supply valve, and delivers control pulses for the activation of the oxygen supply valve. The oxygen supply valve can be arranged in a direct connection line between the oxygen source and the respiratory bag.

The invention will now be described, by way of example, with reference to the drawing which shows an exemplary embodiment of a circulatory respiratory protective apparatus of the invention.

The circulatory respitatory protective apparatus represented schematically Ln the drawings contains components that form a respiratory circuit. The components are held on a carrying frame within an outer protective jacket. A respiratory gas connector 1 is connected, by way of corresponding non-return valves 2 and 3, to an inhalation line 4 and to an exhalation line 5 of the circuit. In the exhalation line 5, there is located a regeneration cartridge 6 for binding the carbon dioxide present in the exhaled air. The outlet of the regeneration cartridge 6 is connected to a respiratory bag 7 in the form of a bellows and to an inhalation line 4. In this way, there is formed a closed circuit.

Oxygen can be fed into the respiratory bag 7, by way of an oxygen supply valve 8, from an oxygen source 9 by way of a connection line 10. Connected downstream of the oxygen source 9 in the connection line 10 there is a bottle valve 11 and a pressure reducer 12. A monitoring line 14 able to be closed by a valve 13 is connected to a pressure manometer 15 for measuring the oxygen supply pressure.

The oxygen supply value 8 is an electromagnetic is valve that receives control pulses from an amplifier 16 by way of a transmitter 17 which is connected to an indicator device 18 which makes the operation of the oxygen supply valve 8 optically visible.

The amplifier 16 is connected on the input side to a movement sensor 19 in the form of a wire strain gauge. This movement sensor can also advantageously consist of a plurality of connected individual sensors, in particular wire strain gauges. It is located on a thorax belt 20 provided with carriers 21 and 22 so that it can be supported on the body of the wearer of the apparatus. The thorax belt 20 and the movement sensor 19 should be worn in such a position on the breast that a maximum amount of movement occurs. Thus, the thorax belt itself preferably consists of an elastic material.

When using the circulatory respiratory protective apparatus. the respiratory gas connection 1 is connected to the mask of the wearer of the apparatus.

The thorax belt 20 is worn on the circumference of the breast.

In the inhalation phase, the mobile sensor 19, in the form of a wire strain gauge, expands and emits, by is way of a connecting line 23, a control signal to the amplifier 16. This controls, by way of the transmitter 17, the magnetic valve 8 for effecting a short-term release of oxygen from the connection line 10 into the respiratory bag 7. In the exhalat ion phase. the magnetic valve 8 is closed. In each inhalation phase, therefore. a pulse of oxygen is fed into the respiratory bag 7.

For metering. the wearer of the apparatus thus requires no lung force because the supply of oxygen adapts to the amount required. If the rate of respiration increases, the rate of the oxygen pulses is also increased.

Since control with restricted thorax movement can be restricted during resting (because small thorax expansions are generally hard to detect with a movement sensor and are hard to distinguish from interfering signals occurring due to body movements. as already described), a permanent supply for low oxygen consumption can be additionally provided. This can advantageously consist of a timer which controls the amplifier 16, independently of the signal from the movement sensor 19, in a timed manner for periodic opening of the magnetic valve 8. Thus, pulses of oxygen are supplied independently of the respiratory movement and the associateb thorax expansion. at regular intervals and ensure a minimal requirement of oxygen (approximately 0.5 litres/minute). Upon thorax expansion, the movement sensor 19 supplies an additional input to the amplifier 16 and extends the duration of the pulse, by controlling the opening time of the magnetic valve 8.

Claims

1. A circulatory respiratory protective apparatus, comprising a respiratory bag which is connected to an oxygen supply valve controlled by the respiratory activity of the wearer of the apparatus. wherein, for controlling the oxygen supply valver a sensor is provided outside of the respiratory circuit of the apparatus.

2. An apparatus according to claim 1, wherein the sensor is a sensor adapted to sense movement of the thorax of the wearer of the apparatus.

3. An apparatus according to claim 2, comprising means for supplying a fixed amount of oxygen to the respiratory circuit, the movement sensor being used for controlling the supply of an increased amount of oxygen.

4. An apparatus according to claim 2 or 3, wherein the sensor comprises at least one strain gauge and a thorax belt.

5. An apparatus according to claim 2 or 3. wherein the sensor includes means for generation of a signal for controlling the oxygen supply valve from several movements of the thorax occurring one after the other.

6. An apparatus according to claim 5, comprising means for storing electrical signals derived from the respiratory movement, and means for comparing a predetermined number of signals of the respiratory movement and for thereby forming the control signal for controlling the oxygen supply valve.

7. An apparatus according to claim 6, yherein the means for comparing a predetermined number of signals is a window comparator.

8. An apparatus according to claim 1, wherein the sensor is a sensor for measuring oxygen partial pressure, able to be put on the skin surface of the wearer of the apparatus.

9. An apparatus according to any of claims 1 to 7, wherein the sensor is connected to an amplifier which is connected by way of a transmitter to the oxygen supply valve.

10. An apparatus according to any of claims 1 to 8, wherein the oxygen supply line is arranged in a direct connection line between an oxygen source and the respiratory bag.

11. An apparatus according to claim 1, substantially as described with reference to the drawing.

I Published 1990wtThe Patent =ice, State House. 8671 High Holborn. London WC1 R 4TP. Further copies may be obtamedfrom The Patent Office. Mes Branch. St Mary Cray, Orpington, Kent BR5 3RD- Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con 1,187