Valves having an inner assembly comprising: a base plate spaced apart from a top plate to define therebetween an open side, the base plate defining an outlet; an outer assembly comprising solid side walls and being movable relative to the inner assembly between open and closed positions, an upper portion of the solid side walls seal with the top plate only when the outer assembly is in the closed position, a lower portion of the solid side walls seal with the base plate only when the outer assembly is in the closed position, wherein the open position allows flow through the valve via the open side portion and the outlet of the outer assembly; and an actuator mounted to the inner assembly and connected to the outer assembly to move the outer assembly between the open and closed positions in response to electrical control signals.