A parallel slide gate valve, comprising: a valve stem coupled to an obturator and configured to translate the obturator relative to a valve body between an open position and a closed position; the valve body comprising an interior surface, wherein a portion of the interior surface defines at least one groove having a longitudinal axis oriented parallel to the valve stem and substantially perpendicular to a direction of flow along a fluid flow path through the valve body, characterised by the at least one groove having a first width at a first end proximate to the fluid flow path and a second width at a second end distal from the fluid flow path, the second width smaller than the first width; the obturator coupled to the valve stem comprising a first generally planar member, a second generally planar member, and a biasing member between the first generally planar member and the second generally planar member, wherein the first generally planar member is oriented substantially parallel to the second generally planar member, wherein the obturator comprises at least one guide rail comprising a portion of each of the first generally planar member and the second generally planar member, protruding out of and perpendicular to the fluid flow path into the at least one groove in the valve body, and configured to move at least partially within the at least one groove when the obturator translates from the closed position to the open position; and wherein the obturator is configured to translate from the first end of the at least one groove toward the second end of the at least one groove as the obturator moves from a closed position to an open position. a valve stem coupled to an obturator and configured to translate the obturator relative to a valve body between an open position and a closed position; the valve body comprising an interior surface, wherein a portion of the interior surface defines at least one groove having a longitudinal axis oriented parallel to the valve stem and substantially perpendicular to a direction of flow along a fluid flow path through the valve body, characterised by the at least one groove having a first width at a first end proximate to the fluid flow path and a second width at a second end distal from the fluid flow path, the second width smaller than the first width; the obturator coupled to the valve stem comprising a first generally planar member, a second generally planar member, and a biasing member between the first generally planar member and the second generally planar member, wherein the first generally planar member is oriented substantially parallel to the second generally planar member, wherein the obturator comprises at least one guide rail comprising a portion of each of the first generally planar member and the second generally planar member, protruding out of and perpendicular to the fluid flow path into the at least one groove in the valve body, and configured to move at least partially within the at least one groove when the obturator translates from the closed position to the open position; and wherein the obturator is configured to translate from the first end of the at least one groove toward the second end of the at least one groove as the obturator moves from a closed position to an open position.