A non-contacting adhesive dispenser comprising: a base structure (425, 525, 625); a valve assembly (410, 510, 610) reversibly secured to said base structure (425, 525, 625) and defining at least one adhesive-dispensing nozzle (415 N) configured to place an adhesive that is received from a source onto an adhesive-receiving substrate in such a way to avoid contact between said valve assembly (410, 510, 610) and said substrate during adhesive dispensing; at least one guiding surface (420, 520, 620, 720) that is rigidly mounted, removably coupled, or removably and reversibly mounted to said base structure (425, 525, 635) or said valve assembly (410, 510, 610), to accommodate various sheet-feeding and liquid-dispensing configurations, characterized by said guiding surface (420, 520, 620, 720) comprising a pair of vertically-spaced guiding surfaces (420, 520, 620, 720) defining a travel path (A-A) for said substrate along a substantially horizontal orientation between the pair of guiding surfaces; a seal (430, 530, 630, 730, 830, 930) reversibly secured to said base structure (425, 525, 625) and movable relative to said nozzle (415 N) to permit selective closure thereof during periods of inoperability of a gluing station that acts as said source of said adhesive such that during such periods, residual portions of said adhesive within said nozzle (415 N) are substantially isolated from an ambient atmospheric environment; and wherein said valve assembly (410, 510, 610) and said seal (430, 530, 630, 730, 830, 930) are reversibly secured to said base structure (425, 525, 625) through at least one attachment that permits at least one of them to be interchangeably disposed above or below said travel path (A-A). a base structure (425, 525, 625); a valve assembly (410, 510, 610) reversibly secured to said base structure (425, 525, 625) and defining at least one adhesive-dispensing nozzle (415 N) configured to place an adhesive that is received from a source onto an adhesive-receiving substrate in such a way to avoid contact between said valve assembly (410, 510, 610) and said substrate during adhesive dispensing; at least one guiding surface (420, 520, 620, 720) that is rigidly mounted, removably coupled, or removably and reversibly mounted to said base structure (425, 525, 635) or said valve assembly (410, 510, 610), to accommodate various sheet-feeding and liquid-dispensing configurations, characterized by said guiding surface (420, 520, 620, 720) comprising a pair of vertically-spaced guiding surfaces (420, 520, 620, 720) defining a travel path (A-A) for said substrate along a substantially horizontal orientation between the pair of guiding surfaces; a seal (430, 530, 630, 730, 830, 930) reversibly secured to said base structure (425, 525, 625) and movable relative to said nozzle (415 N) to permit selective closure thereof during periods of inoperability of a gluing station that acts as said source of said adhesive such that during such periods, residual portions of said adhesive within said nozzle (415 N) are substantially isolated from an ambient atmospheric environment; and wherein said valve assembly (410, 510, 610) and said seal (430, 530, 630, 730, 830, 930) are reversibly secured to said base structure (425, 525, 625) through at least one attachment that permits at least one of them to be interchangeably disposed above or below said travel path (A-A).