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Needle valve and ball valve process and structure
Needle valve and ball valve are common industrial control valves, which are mainly used for precise regulation and cutoff of fluid flow. Although they are different in application occasions, there are many similarities in the process and structure of the two, especially in valve body manufacturing, sealing performance, valve core movement principle, etc.

Needle valve is a precision regulating valve, which is widely used in occasions requiring high-precision flow control, such as gas pipelines, liquid pipelines, pressure testing devices, etc. The structure of the needle valve is relatively simple, usually consisting of a valve body, a valve cover, a valve core (needle), a handle or operating device, a sealing material, etc. The valve body is usually made of corrosion-resistant materials such as stainless steel, copper alloy, aluminum alloy, etc., with good mechanical strength and high temperature resistance to ensure that the valve does not deform or leak during operation.

The core structure of the needle valve is the valve core (needle) and the valve seat. The valve core is conical in shape and is connected to the valve stem by threads. During operation, the handle or knob is rotated to drive the valve stem to move up and down in the vertical direction, thereby adjusting the gap between the valve core and the valve seat to achieve precise flow adjustment. The tip shape and size of the valve core are crucial to the accuracy of flow control. Precision machining technologies such as grinding and polishing are often used to ensure smooth contact and good sealing between it and the valve seat.

The flow control of the needle valve mainly relies on the slight adjustment of the valve core. When the valve core slightly contacts the valve seat, the amount of fluid passing can be very accurately controlled. In order to ensure good sealing, the valve core and valve seat usually use flexible sealing materials such as PTFE (polytetrafluoroethylene) or metal hard sealing design to ensure that they can maintain long-term stability even under high pressure or high temperature environments.

In contrast, the ball valve (Cock Valve) is a switch valve with a simpler structure. It mainly cuts off or connects the fluid channel by rotating the ball. The valve body of the ball valve is generally in a straight-through shape, with a rotatable ball inside and a through hole on the ball. When the ball rotates, the through hole will align with the flow channel of the pipeline, allowing the fluid to pass. When the through hole is not aligned with the flow channel, the fluid is cut off.

The process requirements of the ball valve are mainly reflected in the finishing and sealing design of the ball. The ball is usually made of high-hardness materials such as stainless steel and aluminum alloy to ensure that it is not easy to wear during the switching process and can maintain sealing for a long time. The sealing surface of the ball valve is usually the contact surface between the ball and the valve seat, so the processing accuracy is high. The selection of sealing materials is also very critical. PTFE or other corrosion-resistant materials are usually used to ensure that the valve can work normally under different media and pressure conditions.

The advantage of the ball valve is that it opens and closes quickly, especially for occasions with frequent opening and closing. Compared with the needle valve, the ball valve has poor flow regulation ability and is mainly used for full open or full closed operation. However, due to its simple structure and convenient operation, it is widely used in gas and liquid pipeline control systems.

Although the process requirements of needle valves and ball valves are different, both emphasize sealing and durability. In the manufacturing process, complex machining processes such as milling, turning, grinding, etc. are involved to ensure the dimensional accuracy and surface finish of key components such as valve body, valve core, and ball. In addition, with the development of industrial automation, modern needle valves and ball valves may also be equipped with electric or pneumatic drive devices to further improve the convenience and accuracy of operation.

In terms of structure, the design of needle valves is relatively complex, especially the precision design and processing of valve cores, which usually requires the use of CNC technology, precision casting and other processes to ensure its accuracy. The structure of ball valves is relatively simple, but the processing accuracy requirements for the ball and valve seat are also very high, especially in the case of high-speed opening and closing, the sealing performance between the ball and the valve seat is particularly important.