A devolatilizer (devo), which operates at a temperature and at a pressure, for the separation of at least a portion of a solvent from a polymer-rich solution comprising the solvent and a polymer, and wherein the devolatilizer comprises at least the following components: A) a heater/distributor combination (component A) of length L, the vertical distance from the top to the bottom of the component A; B) a shroud (component B) located around some or all of the periphery of component A; and wherein the shroud comprises at least one cylindrical section situated outside the periphery of component A, and wherein this cylindrical section encloses at least a portion of the periphery of component A, and C) a gap (component C) located between the outer surface of component A and the inner surface of component B, and wherein the gap has a width (w), the distance from the outer surface of component A to the inner surface of the at least one cylindrical section of component B, and the gap has a length ≤ L; and wherein w is downwardly widened continuously or discontinuously along the length L; wherein component A comprises an inner channel, and a plurality of cross-sectional openings extending from the inner channel to the gap; the devolatilizer configured to receive a polymer rich solution in the inner channel, which moves radially through the cross-sectional openings, and within each opening, some or all of the solvent of the polymer rich solution is vaporized, forming a solvent vapor and a polymer melt; and wherein the polymer melt enters the gap, and flows downward from the point of entrance into the gap, and wherein some or all of the solvent vapor flows downward from the point of entrance into the gap; wherein for each vertical distance, y, as measured from the top of the outer surface of component A, the total amount of the solvent vapor that leaves component A at the given distance y, and flows downward into component C, has the following velocities: a) within the gap, an average vertical downward velocity, defined as the ratio of "the total solvent vapor flow rate" to "the cross-sectional area available for flow," and wherein each of "the total solvent vapor flow rate" and "the cross sectional area available for flow" is measured at the same vertical distance, y, and b) a radial average velocity exiting the component A, defined as the ratio of "the total solvent vapor flow rate at the exit of component A, at the temperature and pressure of the devolatilizer" to "the number of openings in component A multiplied by the cross-sectional area of each opening;" wherein the average vertical downward velocity ≤ the radial average velocity exiting the component A. A) a heater/distributor combination (component A) of length L, the vertical distance from the top to the bottom of the component A; B) a shroud (component B) located around some or all of the periphery of component A; and wherein the shroud comprises at least one cylindrical section situated outside the periphery of component A, and wherein this cylindrical section encloses at least a portion of the periphery of component A, and C) a gap (component C) located between the outer surface of component A and the inner surface of component B, and wherein the gap has a width (w), the distance from the outer surface of component A to the inner surface of the at least one cylindrical section of component B, and the gap has a length ≤ L; and wherein w is downwardly widened continuously or discontinuously along the length L; wherein component A comprises an inner channel, and a plurality of cross-sectional openings extending from the inner channel to the gap; the devolatilizer configured to receive a polymer rich solution in the inner channel, which moves radially through the cross-sectional openings, and within each opening, some or all of the solvent of the polymer rich solution is vaporized, forming a solvent vapor and a polymer melt; and wherein the polymer melt enters the gap, and flows downward from the point of entrance into the gap, and wherein some or all of the solvent vapor flows downward from the point of entrance into the gap; a) within the gap, an average vertical downward velocity, defined as the ratio of "the total solvent vapor flow rate" to "the cross-sectional area available for flow," and wherein each of "the total solvent vapor flow rate" and "the cross sectional area available for flow" is measured at the same vertical distance, y, and b) a radial average velocity exiting the component A, defined as the ratio of "the total solvent vapor flow rate at the exit of component A, at the temperature and pressure of the devolatilizer" to "the number of openings in component A multiplied by the cross-sectional area of each opening;"