Continuous steam generator with equalizing chamber

An evaporator for evaporating a liquid in a heat recovery steam generator, the evaporator comprising:

• a duct having a heated fluid flow passing therethrough in a flow direction, and
• a plurality of harps disposed sequentially in the duct in the flow direction, wherein a portion of each harp is disposed transversely in the duct, each harp including:
• a lower header with a liquid input pipe;
• a plurality of lower tubes, each having an upper end and a lower end, the lower ends of the lower tubes being fluidly connected to the lower header;
• an intermediate chamber fluidly connected to the upper ends of the lower tubes,
• plurality of upper tubes having an upper end and a lower end, the lower ends of the upper tubes being fluidly connected to the intermediate chamber;
• and
• an upper header fluidly connected to the upper ends of the upper tubes;
• wherein the plurality of upper tubes, the plurality of lower tubes and the intermediate chamber are disposed in the duct transversely to the flow direction of the heated fluid flow, and wherein the flow direction of the heated fluid below the intermediate chamber is in the same direction as the flow direction of the heated fluid above the intermediate chamber;
• and
• wherein the upper tubes of each harp and respective lower tubes of each harp are vertically offset.

An evaporator for evaporating a liquid in a heat recovery steam generator, the evaporator comprising:

• a duct having a heated fluid flow passing therethrough in a single flow direction, and
• a harp having a portion disposed transversely in the duct, the harp including:
• a lower header with a liquid input pipe;
• a plurality of lower tubes, each having an upper end and a lower end, the lower ends of the lower tubes being fluidly connected to the lower header;
• an intermediate chamber fluidly connected to the upper ends of the lower tubes,
• a plurality of upper tubes having an upper end and a lower end, the lower ends of the upper tubes being fluidly connected to the intermediate chamber;
• and
• an upper header fluidly connected to the upper ends of the upper tubes;
• wherein the heated fluid flow passes through the harp in a single direction,
• wherein the flow direction of the heated fluid below the intermediate chamber is in the same direction as the flow direction of the heated fluid above the intermediate chamber;
• and
• wherein the plurality of upper tubes and the plurality of lower tubes are vertically offset for promoting mixing of the fluid and steam in the intermediate chamber before passing through the plurality of upper tubes.