Abstract: Apparatus, systems and methods for use in three-dimensional printing are shown and described. Various embodiments of the invention allow for more precise and controlled delivery of heat to achieve interlayer drying; isolation of the working region from the outside for reasons of cleanliness and in connection with the vapors of organic solvents; better control of the temperature of the working region; better accuracy in the flowrates of binder fluid dispensed; matching of delivered flowrates for multiple dispensers; verification of delivered flowrate or drops; provision for easier changeover of the machine from one powder to another; cleanability; and other needs.