Electro-pneumatic converter, use of an electro-pneumatic converter, positioner, and control unit
AssigneeSamson Aktiengesellschaft
InventorsSebastian Tietz, Christian Mellinger, Stefan Kolbenschlag
Life of this patent
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Abstract
An adjustable electro-pneumatic converter or transducer based on the nozzle/baffle plate principle is proposed. A defined roughness (Rz) of the baffle plate surface can prevent the occurrence of Bernoulli forces at output pressures close to the initial pressure, i.e. when the exhaust nozzle (140) is almost completely closed by the baffle plate (100). The system thus becomes more dynamically controllable under these conditions. Such a converter can be used to control any consumer system, e.g. air power amplifiers for electro-pneumatic positioners.
Claims12
Electro-pneumatic converter having a baffle plate (100), an exhaust nozzle (140, 150) completely or partially closable by said baffle plate (100) with an exhaust nozzle aperture (180) and an output pressure (Pa), wherein
- 1.1 the air flows turbulently between the baffle plate (100) and the exhaust nozzle edge surface (150),
- 1.2 when the exhaust nozzle aperture (180) is closed by the baffle plate (100) except for a gap (170), wherein the gap (170) is less than 30 μm wide;
- 1.3 the initial pressure (Pv) and the ambient pressure (Pu) are constant and an output pressure (Pa) is regulated;
- and
- 1.4 the width (s) of the edge (150) of the exhaust nozzle (140) is proportional to the sum of the roughness depths (Rzp) of the surface of the baffle plate (100) in the area of the exhaust nozzle aperture (180) and RzD of the surface of the edge (150) of the exhaust nozzle (140);
- 1.4.1 wherein the proportionality factor
- K=s/(RzP+RzD)
- has a value between 10 and 28.
Dependencies are inferred from the claim text.