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Valveless System

Breathe Easier

All of SLE's ventilators use 'valveless technology'. This means that the management of the airflow is not controlled by a mechanical valve, but by a jet of air, acting as a pneumatic piston. This system is based on twenty years of patented technology, and offers the user (and patient) some significant advantages.

The first of these is that there is no additional resistance in the circuit. This ensures that even with the smallest of babies there is minimal resistance to flow and the Work of Breathing is kept to a minimum.

Three high-speed air jets also mean that the system is very reactive allowing very precise control of the airflow with none of the problems of inertia and sticking associated with conventional valves.

The simplicity of the design - a single exhalation block and exhaust manifold also mean that cleaning and assembly are much simplified and reduce the chances of infection or mis-assembly.

How it works...

A constant flow of fresh gas at 8 l/min is supplied to the patient circuit. The manifold houses three jets.

  • The front jet generates and opposing flow to the fresh gas, creating PEEP/CPAP.  
  • The rear jet generates the Peak Inspiratory Pressure.
  • The reverse jet is used during High Frequency Oscillation Ventilation to produce an active negative pressure. This makes our ventilators ‘true oscillators’.

All jets are supplied with the same oxygen concentration as the fresh gas supply. The rate and duration of the flow of driving gas to the exhalation manifold, in opposition to the to the fresh gas flow, is controlled by sophisticated software. The opposing flow acts as a pneumatic piston and creates the pressure wave at the ET manifold. Patient and circuit compliance changes are compensated for by the pressure regulators.

Clinical advantages to the user and patient  

  • Reduction in inadvertent PEEP
  • Excellent clearance of expired gases

As there are no valves or any other removable part in the expiratory limb it makes for easier cleaning and assembly thereby minimising the risk of infection or accidents, as well as increasing ease of use.

For further information about SLE's valveless ventilators click here, or email