Mixer and assembly for air-conditioning a rail vehicle
A mixer, which forms the core part of an air-conditioning assembly of a rail vehicle, has two inlets, an outlet, and a central region between the inlets and the outlet. A first inlet is connected to a fresh air supply, and a second inlet is connected to a circulating air supply such that fresh air and circulating air reach the central region, where the circulating air is mixed with the fresh air to obtain supply air. The central region is connected to the fresh air inlet via an opening, which forms a transition region between the fresh air inlet and the central region. The transition region contains a profiled section with a wing-shaped cross-section in the transition region where the supplied fresh air generates negative pressure along the transition region, and the circulating air is suctioned into the central region of the mixer with a boost from the negative pressure.
1. A mixer for an air conditioning assembly of a rail vehicle, the mixer comprising:
two inlets, being a first inlet and a second inlet, an outlet, and a cylindrical central area between the two inlets and said outlet,
said first inlet being connected to a pressurized fresh air supply with a fresh air fan configured to draw in fresh air, to pressurize the fresh air, and to enable pressurized fresh air to reach said central area via said first inlet;
said second inlet being connected to a pressurized circulating air supply having a circulating air fan configured to draw in circulating air from an interior of the rail vehicle, to pressurize the circulating air and enable the circulating air to reach said central area via said second inlet;
wherein the circulating air and the fresh air are mixed in the central area to generate supply air, which passes to said outlet;
said central area being connected to said first inlet via an opening, which forms a circumferential transitional area between said first inlet and said central area, wherein the fresh air is fed from said first inlet to said central area via said transitional area;
said transitional area containing a profile having an airfoil-shaped cross section, said profile being arranged in said transitional area to cause the fresh air to generate a negative pressure along said transitional area to boost an induction of the circulating air into said central area;
said first inlet being a tube arranged radially about a circumference on an outside of the mixer;
said tube being formed with an opening that opens radially to the circumference in a direction of said central area and towards an interior of the mixer and which forms the circumferential transitional area between said inlet and said cylindrical central area.
2. The mixer according to claim 1 , wherein:
the airfoil-shaped cross section of said profile has a surface curved inwardly in a direction of the fresh air or in a direction of said first inlet;
the airfoil-shaped cross section of said profile has a surface curved outwardly in a direction of the circulating air or in a direction of said cylindrical central area; and,
said outwardly curved surface of said profile is arranged opposite said opening and separated therefrom by an air gap.
3. The mixer according to claim 1 , wherein said fresh air fan is configured to draw and pressurize the fresh air before the fresh air reaches said first inlet.
4. The mixer according to claim 3 , wherein said fresh air fan is a side-channel compressor.
5. An air-conditioning assembly for a rail vehicle, the assembly comprising:
a mixer according to claim 1 , configured to generate supply air from the fresh air, which is delivered to the mixer by the fresh air fan via the first inlet, and the circulating air, which is delivered to the mixer by the circulating air fan via the second inlet;
said mixer having an outlet side connected to an air conditioning unit, wherein the supply air is delivered to said air conditioning unit for generating conditioned supply air and adjusting an air temperature;
a supply air fan connected to an outlet side of said air conditioning unit for delivering the conditioned supply air via a ducting system into an interior of the rail vehicle; and
the interior of the rail vehicle communicating with the second inlet of said mixer via the ducting system and the circulating air fan, so that at least a proportion of the conditioned supply air passes via said ducting system from the interior to the second inlet of said mixer as the circulating air.