The gate valve's opening and closing element is the gate. The gate's movement direction is perpendicular to the fluid's movement direction. Gate valves can only be fully open or fully closed. In a square-type gate valve, the two sealing surfaces form a wedge shape, with the wedge angle varying depending on the valve parameters, typically 5°, and 2°52′ when the medium temperature is low. To improve its manufacturability and compensate for deviations in the sealing surface angle during processing, this type of gate is called an elastic gate.

When a gate valve is closed, the sealing surface can rely on the medium pressure to seal. The medium pressure presses the gate's sealing surface against the valve seat on the other side to ensure this seal; this is called self-sealing. Most gate valves use forced sealing, meaning that when the valve is closed, external force is needed to press the gate against the valve seat to ensure the sealing surface's tightness.

Gate valves where the gate moves linearly along with the valve stem are also called rising stem gate valves. Usually, there is a trapezoidal thread on the rising stem, which, through the nut at the top of the valve and the guide groove in the valve body, mainly changes the movement to linear motion, transforming the operation into thrust. When opening a valve, the fluid passage is completely unobstructed when the gate is raised to a height equal to 1:1 times the valve's diameter under certain operating conditions. However, this position cannot be monitored during operation. In actual use, the main apex of the valve stem, i.e., the position where it cannot be opened further, is usually used as the fully open position of the valve stem. To account for potential locking due to temperature changes, the valve is usually opened to the apex position and then turned back 1/2 to 1 turn to define the fully open position. Therefore, the fully open position of the valve is determined by the position of the gate (i.e., the stroke). Some gate valves have the valve stem nut on the gate; rotating the handwheel drives the valve stem to rotate, thus raising the gate. This type of valve is called a rotary stem gate valve or a non-rising stem gate valve.

There are many manufacturers of gate valves in China, and the connection dimensions are mostly inconsistent. They are mainly divided into the following categories: general-purpose types based on JB/T2203-1999 "Gate Valve Structural Length".

This gate valve body is made of high-grade ductile iron, making it 20% to 30% lighter than traditional gate valves, and easier to install and maintain. Flat-bottom gate seat: Traditional gate valves often experience leakage after flushing with water due to the accumulation of foreign matter such as stones, wood chips, cement, iron filings, and other debris in the bottom groove, leading to insufficient tightness and leakage. The resilient-seated flange gate valve uses the same flat-bottom design as the water pipe, preventing any debris accumulation and ensuring unobstructed fluid flow. Integral rubber coating: The gate plate is integrally coated with high-quality rubber both internally and externally. Precision cast valve body: The valve body is precision cast, ensuring a tight seal without any internal machining.