What is the working principle of a needle valve?

It is a type of throttle valve with high adjustment precision. The valve element is needle-shaped and moves in the direction of the water flow, thereby changing the cross-sectional area through which the fluid flows; it is used to stop or regulate the flow rate. 　　A needle valve is a fine-tuning valve whose plug is needle-shaped, and it is primarily used to regulate gas flow rate. The fine-tuning valve requires the valve opening to increase gradually, allowing for continuous and precise adjustment from closed to fully open. A needle-shaped valve plug can achieve this function. Pin-type valve plugs are generally made of hardened steel pins, while the valve seats are constructed from soft materials such as tin and copper. The sealing between the valve needle and the valve seat is achieved through a tight fit of their conical surfaces. The taper of the valve needle is available in two angles: 1:50 and 60, and the tapered surface must be finely ground. The sealing between the valve stem and the valve seat is achieved through a bellows. 　　Maximum operating pressure: 6000 PSI (414 Bar) Maximum temperature range: -65°F — 600°F (-54°C — 316°C) Valve size: (Imperial) 1/8” — 1/2” (Metric) 6mm — 12mm Connection types: Gyrolok double ferrule, NPT threads Valve body materials: Copper, 316SS, carbon steel, and various special materials Flow capacity Cv: 0.4 — 1.2

Reply to 2# dalian*aochao: Haha, what you said is great! Thank you

:), it’s the basics of chemistry; I come into contact with these things every day nowadays