Vyaire VELA, Руководство по обслуживанию

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2-2
Chapter 2: Theory of Operation
33373-001 Version A
2.2.3 Safety System
The mechanical safety system ensures that the patient can breath spontaneously from room air and
that the patient pressure is limited to a maximum preset value in the event of a ventilator
malfunction. This mechanical system consists of a pressure relief valve and a sub ambient relief
valve. In the event of a ventilator malfunction that results in high pressure, the pressure is limited by
a relief valve. The relief valve consists of a user-adjustable, spring-loaded poppet acting against a
seat.
In the event the ventilator fails to deliver a breath, the patient may inspire spontaneously by drawing
room air through the sub ambient relief valve.
Materials exposed to patient gas are aluminum, compatible rubber, and compatible plastics.
2.2.4 Inspiratory Hold Valve
The inspiratory hold valve is an electromechanical solenoid valve. If activated, the inspiratory hold
valve blocks flow between the flow delivery system and the patient. This valve is activate during
inspiratory hold and maximum inspiratory pressure maneuvers. Materials exposed to patient gases
are aluminum and compatible rubber and plastic.
2.3 Oxygen Blending System
The oxygen blending system is made up of an O2 inlet transducer, an O2 inlet pressure regulator,
seven solenoid valves, five flow orifices, one nebulizer orifice, an inlet filter, and an accumulator.
When a breath is initiated, the turbine draws mixed gas from the accumulator. Filtered air is drawn
into the accumulator through the filter. Oxygen is supplied to the accumulator through the solenoids
and orifices. The microprocessor opens and closes the valves as required to supply the correct
amount of oxygen to satisfy the O2 setting and the flow demand. The signal from the O2 inlet
pressure transducer is used to compensate delivered O2 for O2 inlet pressure variations. The
blender can be used to supply nebulized flow at 100% oxygen. A safety solenoid is used to shut off
the flow of oxygen when the ventilator is turned off or has gone inoperative. The O2 inlet pressure
regulator helps minimize variations in the oxygen supply. Surfaces exposed to patient gas are
constructed from compatible plastics, plated steel, and aluminum.
There is also an oxygen inlet port, which allows for low-flow titration of oxygen into the gas output of
this device.
2.4 Electronic Overview
The VELA ventilator electronic system is comprised of several subsystems, each containing
numerous components. These subsystems are the GUI System, the Power System, the Main
Microprocessor System, and the Exhalation and Flow Delivery systems. Individual subsystems are
discussed in detail.
2.4.1 User interface module (UIM)
The UIM consists of a 10.4-inch, 800x600 active matrix LCD with an analog resistive touch screen
overlay, a back light inverter, a set of membrane key panels, an optical encoder, and the Main
System PCB. Software and the touch screen provide a set of context sensitive soft keys. The
membrane panel provides a set of hard (permanent) keys for dedicated functions. Selecting the
function with a soft key and adjusting the setting using the optical encoder changes a parameter. A
parameter is accepted or canceled by pressing the appropriate membrane key.
The UIM performs all ventilator control functions, gas calculations, monitoring and user interface
functions. The UIM uses a Graphical User Interface (GUI) via the active matrix SVGA LCD and