GB2160108A

GB2160108A - A respiratory gas control mechanism

Info

Publication number: GB2160108A
Application number: GB08513484A
Authority: GB
Inventors: Adalbert Pasternack
Original assignee: Draegerwerk AG and Co KGaA
Current assignee: Draegerwerk AG and Co KGaA
Priority date: 1984-06-15
Filing date: 1985-05-29
Publication date: 1985-12-18
Also published as: IT8511683V0; IT207146Z2; JPS618061U; GB8513484D0; FR2565830B3; FR2565830A3; GB2160108B; SE8502911L; SE8502911D0

Abstract

In a circulatory protective respiratory apparatus, provision is made for a constant inflow of respiratory gas. A gas control mechanism has a defined adjusted setting (3) for the constant dosage, with which the specific requirement can be easily regulated. Adjusting screw (10) operated by hand, deflects, with a stop, the rocking lever (6) of a rocking valve (7) of the lung-controlled device so that the respiratory gas can flow in accordingly. Spring-loaded pins (11) in the adjusting screw engage bore holes (12) of a threaded housing (9) for the adjusting screw and hold the latter securely in the adjusted setting. Only with increased demand does a membrane (5), which is moved responsive to respiration of the user, deflect the rocking lever further and dose an additional required quantity of respiratory gas. <IMAGE>

Description

SPECIFICATION A respiratory gas control mechanism This invention relates to a respiratory gas control mechanism.

It is known, in circulatory protective respiratory apparatus, to enable a supply of oxygen to be adjusted to a constant dosage with, in the case of increased demand by a wearer, any extra oxygen being subsequently supplied via a lung controlled device. In this type of apparatus however, it is generally necessary to provide a constant flow of oxygen in excess of requirements, otherwise there is a frequent need to actuate the lung controlled device, which results in increased physical strain for the wearer and consequent disruptions.

A respiratory gas control mechanism for protective respiratory apparatus is discussed in British Patent Specification No. 969 280. It is constructed with an automatic lung-controlled valve and with an additional, constant supply of respiratory gas. In the lung-controlled valve, a membrane acts on a rocking lever valve to control the supply of respiratory gas according to the respiratory activity of the wearer of the apparatus. The simultaneous, constant supply of respiratory gas is obtained by means of a stop which may be displaced from outside the apparatus by a handwheel via a spindle and which lifts the membrane out of its rest position or catches it on its return into said rest position, before said position is reached. In this way, the rocking valve is either opened, or its complete closure is prevented, according to the previous position of the membrane.A constant supply of respiratory gas to the wearer of the apparatus is thereby achieved.

The dosage of respiratory gas depends here on the position of the membrane. However, in use, inertia forces, such as vibrations or pressure fluctuations resulting from the wearer's breathing act on the membrane, and so the latter does not form a defined stop.

The fluctuations of the membrane are transmitted to the rocking lever, controlling the rocking valve and lying against the membrane, and result in irregularities in the desired dosage.

According to the present invention there is provided a respiratory gas control mechanism comprising: a gas supply valve, controllable by means of a control member to adjust the supply of gas from a respiratory gas source to a user; an adjusting element having a surface for abutment against said control member to retain said control member in such a position as to permit a substantially constant flow of gas to be supplied to the user, said constant flow being adjustable by means of the element; and means responsive to respiration of the user for displacing said control member to increase the flow of gas to the user, if required.

In a preferred embodiment the adjustable element is an adjusting screw disposed in a threaded housing and having a stop opposite the control member (or rocking lever) of the gas supply valve.

The stop deflects the control member according to adjustment of the screw and thereby opens the valve for constant dosage. Spring-loaded (or biased) pins, in the adjusting screw for engagement or bore holes in the periphery of the housing may be provided.

The means responsive to respiration of the wearer may comprise a membrane movable by pressure fluctuation to displace the control member, for further opening of the supply valve.

The advantages which can be achieved with embodiments of the invention lie in the fact that with the direct deflection of the control member, defined opening of the supply valve for constant gas dosage is possible in a simple and direct manner.

The small mass of the control member prevents oscillation in the case of vibration. Pressure fluctuations, which are converted into membrane movements, do not affect the control member, which is displaced directly to supply the constant dosage. Such fluctuations do not, therefore, affect the supply valve.

The spring-loaded pins in the adjusting screw guarantee adjustment of the constant dosage. They engage the bore holes in the periphery of the threaded housing to hold the adjusting screw in the chosen adjusted setting.

For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which the Figure is a section through a gas control mechanism in accordance with one embodiment of the present invention.

Figure 1 shows a gas control mechanism having a housing 2 for connection to a suitable point in the respiratory circuit of a protective respiratory apparatus by way of connection piece 4. A lung controlled device or lung automaton 1 has a membrane 5 which is moved by the pressure in the respiratory circuit and which in turn displaces a rocking lever 6 to control, via a spring-loaded rocking valve 7, the supply dosage of the respiratory gas from the connection 8.

An additional, adjustable constant gas dosage is ensured by an adjusting device 3. The device 3 has an adjusting screw 10, which is actuatable by hand, in a nut or threaded housing 9. Springloaded pins 11 engage bore holes 12 (one only of which is shown in the Figure) in the periphery of the housing 9, depending on the turned position of the adjusting screw 10 and thereby guarantee the selected one of several possible positions. These positions define the axial position of the adjusting screw 10 and of a stop 13 provided at the end of the screw 10 and disposed to face the rocking lever 6. The stop 13 presses against the rocking lever 6 according to the desired constant dosage as set by the screw 10 and deflects the lever 6 out of the position in which the rocking valve 7 is closed. The rocking valve 7 thereby opens accordingly so that the constant dosage quantity of respiratory gas flows into the respiratory circuit. With the constant dosage adjusted device 3, the recognized con sumption of respiratory gas, such as oxygen, may be adjusted in a sufficiently exact manner. If a short-term increased demand, for example as a result of deep breaths, should still come about, it is met automatically through further opening via the lung-controlled valve 1 in a manner known per se.

The above described embodiment of the present invention enables defined adjustment of constant gas dosage to be effected, the adjustment being preserved even during intense vibration. Further, through reliable adjustment, frequent actuation with the physical strain resulting therefrom for the wearer of the apparatus is avoided.

Claims

1. A respiratory gas control mechanism comprising: a gas supply valve, controllable by means of a control member to adjust the supply of gas from a respiratory gas source to a user; an adjusting element having a surface for abutment against said control member to retain said control member in such a position as to permit a substantially constant flow of gas to be supplied to the user, said constant flow being adjustable by means of the element; and means responsive to respiration of the user for displacing said control member to increase the flow of gas to the user if required.

2. A mechanism as claimed in claim 1, in which the adjusting element is axially displaceable in a housing provided with recesses, the element having outwardly biased pins for engaging the recesses to secure the element in a selected one of a plurality of axial positions.

3. A mechanism as claimed in claim 1 or 2 in which the adjusting element is a screw which engages a thread of the housing.

4. A respiratory gas control mechanism substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.