2 - Background

2.1 - General principals

There are two main categories of fluid displacement and rotary movement machines:

- piston machines

- machines generically known as « turbines ».

Piston machines operate by volume variations caused by pistons moving from their bottom position to their top position and back again. This movement is able to compress or expand fluids, especially gases.

Piston machines are equipped with mechanisms which can transform a straight-line motion into a rotary motion and vice versa.
These generally complex mechanisms are usually con rod assemblies, but there are also camshafts, swash plates and so on.
The pistons in these machines constantly rub against the cylinder wall.

To withstand the pressure, the pistons must be equipped with pressure rings.

In most cases, including compressors and internal combustion engines, the piston-compression rings-cylinder combination must be cooled to preserve the quality of the lubrication oil and ensure at least oily friction between the various components.

Turbines consist of a rotor equipped with blades turning in a stator. Therefore, they do not need a movement converter.

Turbines cannot operate at high pressures because they do not have a system capable of varying the volumes between the blades. By definition, a turbine cannot be variable volume.

But they do have an advantage: the blades do not rub against the stator.

The « Technology » section below explains how the advantages of piston machines and turbines can be combined to create a machine:

- with no movement converter

- whose components in the work volume do not cause friction;

- which can be used to generate variations in volume and pressure;

- where the seal is created by controlled charge losses.

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