Valve bodies are described herein. A valve body is disclosed to control fluid flow through a drip chamber defining a chamber volume and comprises a chamber body coupling, a valve inlet, a valve outlet, and a needle valve assembly. The chamber body coupling receives the drip chamber. The valve inlet or the valve outlet is configured to be in fluid communication with the chamber volume. The needle valve assembly comprises a fixed needle valve surface; and a movable needle valve surface, wherein the movable needle valve surface is axially movable relative to the fixed needle valve surface to control a flow rate between the valve inlet and the valve outlet.
