The non-rising stem gate valve, also known as the inside screw stem valve, is a common isolation valve. Its closure member is a gate that moves perpendicular to flow direction, designed for fully open or fully closed service only, never for flow regulation.The main gate valves product names of China gate Valve Network include:MZ44W Rising Stem Gas Quick Open&close ParallelMZ48W Manual Non-rising Stem City Gas Quick Gate Valve,Manual Knife-shaped Gate Valve,Manual Slurry ValveManual Wedge Copper Gate Valve,Manual Vacuum Isolated Wedge Gate Valve,Manual Welding Vacuum Wedge Gate Valve,Manual Wedge Gate Valve ,With Purge HoleNon-rising Stem Resilient Seat Seal Gate Valve,Non-rising Stem Wedge Cast Iron Gate Valve

Structural Characteristics

The defining feature of a non-rising stem gate valve is the stem nut located inside the valve body. During operation, the stem rotates without lifting, while the handwheel position remains essentially unchanged. This design makes it ideal for installations with limited space or strict height restrictions.

The stem features trapezoidal threads engaging with a nut inside the body. When the handwheel rotates, it drives the nut, converting rotational motion into linear gate movement through the threads and guide grooves, achieving opening or closing.

The gate has two sealing surfaces, typically using a wedge design with a wedge angle of 5°, or 2°52' for low-temperature media. Wedge gate valves offer two types: solid gate (one-piece construction) and elastic gate (with slight deformability). The elastic gate compensates for angular machining deviations, improving sealing reliability.

Determining Full Open Position

When the gate lifts to a height equal to the valve diameter, the fluid passage is fully open. However, this position cannot be monitored during operation, so the stem top serves as a reference—when rotation stops, this indicates full open. To prevent thermal locking, it is common practice to open fully, then reverse 1/2 to 1 turn to establish the actual full open position.

Technical Requirements

Specifications must comply with pipeline design. Valve models should indicate applicable national standards; enterprise standards require documentation.

Pressure requirements: working pressure must equal or exceed pipeline pressure; in closed position, resilient seated valves must withstand 1.1 times working pressure without leakage; in open position, the body must withstand twice working pressure.

Manufacturing standards must specify national standard numbers; enterprise standards require documentation in purchase contracts.

Non-rising stem gate valves are widely used in water supply, wastewater treatment, and general industrial pipelines. Selection should consider diameter, pressure, medium characteristics, and installation space.

Do you still need to know or purchase the following gate valve products:

• MZ44W Rising Stem Gas Quick Open&close Parallel
• MZ48W Manual Non-rising Stem City Gas Quick Gate Valve
• Manual Knife-shaped Gate Valve
• Manual Slurry Valve
• Manual Wedge Copper Gate Valve
• Manual Vacuum Isolated Wedge Gate Valve
• Manual Welding Vacuum Wedge Gate Valve