There are numerous domestic manufacturers of gate valves, and connection dimensions often lack standardization. They are primarily categorized into the following groups:
1. Valves manufactured according to the Ministry of Machinery Industry standard JB/T 2203–1999 (*Face-to-Face and End-to-End Dimensions of Gate Valves*);
2. Valves manufactured according to the National Standard GB/T 12221-2005 (*Face-to-Face and End-to-End Dimensions of Metal Valves*);
3. Valves manufactured according to the American Standard ASME B16.10-2009 (*Face-to-Face and End-to-End Dimensions of Valves*).
Based on the structure of the gate (disc), gate valves are classified into two types: wedge-type and parallel-type. Wedge-type gates come in three structural variations: single-disc, double-disc, and flexible (elastic) disc.
Based on structural design, gate valves are further categorized into slab gate valves and knife gate valves.
- Working principle of manual gate valves: Rotating the handwheel engages the threads between the handwheel and the valve stem, causing the gate (connected to the stem) to rise or descend, thereby opening or closing the valve.
Based on body material, gate valves can be classified as follows:
- Metal valves: e.g., carbon steel, alloy steel, stainless steel, cast iron, titanium alloy, Monel, copper alloy, and lead alloy valves.
- Metal-bodied valves with linings: e.g., rubber-lined, fluoroplastic-lined, lead-lined, plastic-lined, and enamel-lined valves.
- Non-metallic valves: e.g., ceramic, glass, and plastic valves.
