Surgery – Respiratory method or device – Means for supplying respiratory gas under positive pressure
Reexamination Certificate
1998-08-03
2001-02-06
Mulcahy, John (Department: 3764)
Surgery
Respiratory method or device
Means for supplying respiratory gas under positive pressure
C128S205190, C601S043000
Reexamination Certificate
active
06182658
ABSTRACT:
The present invention relates to fluid control valves, especially for use in controlling fluid flow to ventilator or physiotherapy apparatus.
EP-A-0373153 discloses a ventilator apparatus for use in the ventilation of the lungs of a patient, which apparatus comprises a ventilator enclosure, for receiving the chest region of a patient's body, connected via a fluid control valve both to a positive pressure source and a negative pressure source. The fluid control valve comprises a main port connected to the ventilator enclosure, subsidiary ports connected to a respective one of the positive and negative pressure sources, and a shutter mechanism which alternately permits the application of positive and negative pressure to the ventilator enclosure. With this arrangement the use of separate positive and negative pressure sources, such as a pair of gas blowers, is required. Ideally, for efficiency the use of a single gas blower is however desired. The arrangement disclosed in EP-A-0373153 does not allow for the use of a single gas blower having its positive pressure side connected to one subsidiary port of the fluid control valve and its negative pressure side connected to the other subsidiary port of the fluid control valve since a closed loop would be created with no vent to the exterior of the valve.
WO-94/27553 discloses a fluid control valve which allows the positive and negative pressure sides of a single fluid supply to be connected to a closed system, such as a ventilator enclosure, so as to permit the generation alternately of a positive and negative pressure in the closed system. The fluid control valve comprises a valve body having first and second subsidiary ports for connection to the ventilator enclosure, and a valve means which comprises a shutter mechanism for selectively connecting either the first subsidiary port to the main port whilst blocking the connection path between the second subsidiary port and the main port, or connecting the second subsidiary port to the main port whilst blocking the path between the first subsidiary port and the main port. In order to permit connection to a closed system, the valve means includes a further shutter mechanism which is coupled for synchronous movement with the first-mentioned shutter mechanism so as to provide a temporary connection to the exterior of the valve from whichever of the first and second subsidiary ports is blocked off from the main port. Such an arrangement allows the use of a single fluid supply, and by the use of a shutter mechanism which is capable of progressively closing the path between the main port and the respective subsidiary port, greater control over the shape and intensity of the positive and negative Pressure pulses applied to the main port is provided. However, the arrangement cannot provide a supply of positive and negative fluid pressure at frequencies exceeding 5-6 Hz. The reason for this is that to generate alternately a positive and negative pressure at the main port requires the repeated reversal of the direction of rotation of the shutter mechanism and the frequency of operation of that control valve is limited to the rate at which the direction of rotation of the control motor and hence shutter mechanism can be reversed. Reversal of the direction of rotation of the control motor requires the motor to be brought to stop which introduces an unavoidable minimum time delay.
A fluid control valve has been devised which provides an alternate positive and negative pressure source at an outlet, which uses a single fluid supply and which is capable of operation at high frequencies. Instead of requiring a shutter mechanism which is reversed to provide alternately a positive and negative pressure source at the outlet, the present invention employs a rotary valve member which is continuously rotated in a single sense.
Continuous rotation of the shutter mechanisms employed in the fluid control valve disclosed in WO-94/27553 is not possible since, over a sector of the rotation of the shutter mechanisms, both of the subsidiary ports which are connected to the blower inlet and the blower outlet would at the same time be connected to the main port.
Accordingly, the present invention provides a fluid control valve for connection between a positive fluid pressure source, a negative fluid pressure source and a device to be connected alternately to said pressure sources, comprising a body having ports for connection to said fluid pressure sources and said device, and a rotary member rotatable with respect to said body and adapted selectively to interconnect said ports, whereby said rotary member is operable on rotation in a single sense to connect alternately said positive fluid pressure source and said negative fluid pressure source to said device. Preferably, the fluid control further comprises a port for providing a vent to atmosphere. With this fluid valve, a supply of positive and negative pressure at frequencies exceeding 10 Hz can be provided.
In a preferred embodiment said body comprises a first port for connection to said device, a second port for connection to said positive fluid pressure source, a third port for connection to said negative fluid pressure source and a fourth port for providing a vent to the exterior of said body, and said rotary member is disposed within said body, said rotary member being adapted on rotation selectively to connect said second port to said first port and said third port to said fourth port whilst blocking off connection between said second port and said fourth port and said third port and said first port, and also to connect said third port to said first port and said second port to said fourth port whilst blocking off connection between said second port and said first port and said third port and said fourth port.
The present invention also extends to a ventilator or physiotherapy apparatus for use in the ventilation of the lungs of a patient, comprising an enclosure for receiving at least the chest region of the patients' body, and a means for altering the pressure in the enclosure to produce ventilation, said means comprising a positive fluid pressure source, a negative fluid pressure source and the above-described fluid control valve connected between said sources and said enclosure.
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Hwang Victor K.
Jones Allston L.
Mulcahy John
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