Danfoss A/s

Georg Fosel

Bjarke Skovgard Dam

Louis Sullivan

Carsten Molhede Thomsen

Jens Pawlik

Claus Thybo

An expansion valve () for a vapour compression system, the valve () comprising a first valve part () having an outlet orifice () and a piston () movable inside the outlet orifice () in response to a differential pressure across the expansion valve (), controlling a fluid flow through the first valve part (). A cross-sectional flow area of the outlet orifice () between a circumference at an inner surface of the outlet orifice () and a circumference at an outer surface of the piston () varies as a function of the position of the piston () relative to the outlet orifice (). A first cross-sectional flow area is defined at a first differential pressure, and a second cross-sectional flow area is defined at a second differential pressure, where the first cross-sectional flow area is smaller than the second cross-sectional flow area, and the first differential pressure is lower than the second differential pressure.

Expansion valve with a variable orifice area

An expansion valve () for a vapour compression system, the valve comprising a first valve part () having an outlet orifice () and a piston () movable inside the outlet orifice () in response to a differential pressure across the expansion valve (), controlling a fluid flow through the first valve part (), via a forward fluid passage through the first valve part (). The piston () has different cylindrical shapes stepwise along a longitudinal extension of the piston (), the piston () defining a first cross-sectional area along a first longitudinal extension and a second-cross sectional area along a second longitudinal extension, the first cross-sectional area being smaller than the second-cross sectional area. The first longitudinal extension is in the outlet orifice () at a first differential pressure and the second longitudinal extension is in the outlet orifice () at a second differential pressure, the first differential pressure being lower than the second differential pressure.

Expansion valve with a two-step variable orifice area

An expansion valve () for a vapor compression system, the valve () comprising a first valve part () having an outlet orifice () and a piston () movable inside the outlet orifice () in response to a differential pressure across the expansion valve (), controlling a fluid flow through the valve (). The piston () comprises a stop element () at an outlet end () of the piston () and mechanical forcing means () to force the piston () towards a position in which the stop element () is brought into abutment with a valve seat () of the first valve part (). A differential pressure below a predefined threshold value causes the stop element () of the piston () to abut the valve seat () of the first valve part (), preventing fluid flow through the first valve part (), via the forward fluid passage.

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Flensburg, Germany

Georg Fosel