Needle valves offer economical solutions for applications that require basic adjustable control of hydraulic flow. The effective orifice size inside the valve is varied with screw or knob adjustments and the valve can be made tamper resistant with the addition of an optional cap. Shutoff can be achieved when the valve is adjusted completely closed. Once the adjustment is set, the valve acts as a fixed orifice. Like all fixed orifices, any changes in pressure will cause changes in flow. If constant flow is required regardless of system or load pressure, please consider Parker’s pressure compensated flow controls. Parker’s J02A2, NVH081, NVH101, and J06A2 cartridges are basic 2-port needle valves with fine adjustment options available. The orifice will meter in both directions, but flow from port 2 to 1 is preferred. If unrestricted reverse flow is required, an additional check valve will need to be used with these needle valve versions. Parker also offers J02B2, FV101, and FV102 needle valves with internal reverse free flow checks in order to reduce manifold size and component quantities. Typical applications and industries include Accumulator Bleed-off, Motor Speed Control, Cylinder Speed Control, Bleed-Off Flow, Power Units, Oil and Gas, Material Handling, Construction, Drills, Presses, Mixers, Agriculture, Balers, Combines, etc.