The Digital Breathing Machine
has been developed to provide an accurate method of reproducing human
respiration. A standard breathing machine uses a simple motor driven cam to drive a piston, and is therefore limited to
producing a sine wave breathing pattern. This machine uses an electric actuator to directly control the precise position of
the piston, enabling any breathing waveform to be reproduced. Human breathing can be recorded using an optional measurement
system, and then the machine can reproduce this accurately and repeatably in the laboratory. The machine has been designed
to be capable of exceeding the breathing performance of even the fittest human.
The machine has been recently re-designed to use a high quality PTFE/rubber seal around the piston edge, enabling the
direct use of the machine as part of the pressure circuit for leak tests etc. The piston seal is capable of seals pressures
in excess of 50 bar, though at these elevated pressures the piston needs pressure balancing to reduce the load on the actuator
for greater accuracy of reproduction. Contact us
for more information on the use and
configuration of the machine.
The crux of the system is not the hardware itself, but the software that drives it. The system uses the LabVIEW data
acquisition and control software from National Instruments. The machine is fitted with a low cost USB data
acquisition card and this interfaces with the control computer, passing data and control signals to and fro as
Custom software is supplied to drive the Digital Breathing Machine. This is able to reproduce any breathing waveform
the human lung can perform. Software is supplied to create waveform files as simple sinewaves or complex described
waveforms, or even live subject tests (this needs a suitable flow measurement device). Once a waveform file is created
it is stored in the computer to be called up and reproduced as required.
The system is capable of recording and reproducing real life human breathing patterns, when used in conjunction with
suitable breathing recording equipment (which can be supplied). Up to one hours subjective flow measurement can be
recorded and then reproduced as required. Again, these files are stored on the computer for reproduction as needed.