Structure Overview of High-pressure Valves

High-pressure valves serve as control devices for fluid pipelines. Their primary function is to open or shut off the flow of pipeline media, alter the direction of flow, regulate pressure and flow rate, and safeguard the normal operation of pipelines and equipment.

High-pressure gate valves can be divided into wedge and parallel types based on the structure of the gate, and into rising stem and non-rising stem types based on the stem's operation mode. The wedge-type gate valve features a gate resembling a wedge inserted into the valve seat. In contrast, the parallel-type gate valve utilizes blocks between the two gate plates to squeeze and separate them with the movement of wedge-shaped blocks, ensuring a tight seal. The rising stem gate valve allows for easy observation of the valve's open/close status, while the non-rising stem gate valve occupies less space but is prone to corrosion by fluid inside the pipeline.

The main components of high-pressure gate valves include the gate, valve body, bonnet, stem, gland nut, packing gland, and handwheel. These valves are typically made from materials like cast iron, cast steel, and stainless steel, providing versatility in installation without directional constraints.

High-pressure gate valves are characterized by low resistance, easy flow rate adjustment, slow opening, and absence of water hammer effects, making them suitable for various liquid and gas pipeline applications. However, they have a complex structure, large size, high price, and are prone to rapid closure surface wear, making maintenance challenging. Additionally, the accumulation of solid particles in valve seats can lead to imperfect closure, making them unsuitable for pipelines containing solid particles or highly corrosive fluids.

High-pressure globe valves come in various forms, including straight-through, angle, and direct-flow types, each with different resistance levels and suitable for specific fluid conditions. They consist of a valve body, disc, stem, seat, and gland, with materials like cast iron, cast steel, alloy steel, stainless steel, bronze, and brass commonly used. The sealing surface of the valve disc and seat can be either flat or conical, with each type having its advantages and limitations.

High-pressure check valves are divided into lift and swing types. Lift check valves feature a valve disc that moves vertically within the valve body, while swing check valves rotate around the sealing surface, offering lower resistance but weaker sealing at low pressures.

High-pressure diaphragm valves consist of a valve body, bonnet, disc, diaphragm, stem, and handwheel. They are suitable for corrosive fluid pipelines, with the rubber-lined inner surface providing enhanced sealing properties.

High-pressure butterfly valves are compact, lightweight, and easy to operate, with a body and weight only 30% and 20% of those of high-pressure gate valves of the same specifications, respectively. They are comprised of a valve body, rubber gasket, disc, stem, and manual or electric actuator.

The opening and closing of high-pressure valves are controlled by different drive mechanisms, with the stem driving the disc to produce a 90-degree rotation. Clockwise rotation opens the valve, while counterclockwise rotation closes it.