Energy Saving Single Air Valve Versatile Easy Installation Safety

Working Pressure:16kg/cm²
Shell Test Pressure:24kg/cm²
Seat Test Pressure:18kg/cm² 
Media:Water,Neutral Oil
Working Temperature:0-52°C 100％

Fusion Bonded Epoxy Coating for Inner and Outside Surface 
Size:DN25

Small Pipes, Big Air Problem — Why a DN25 Air Valve Saves More Than You Think

In a DN500 transmission main, a 5 mm air pocket is a rounding error — 0.01% of the cross-section. In a DN25 branch line, the same 5 mm air pocket blocks 4% of the pipe. A 10 mm pocket blocks 16%. The hydraulic impact of air in small-bore pipe is disproportionate: because the pipe cross-section is small, even a small air accumulation creates a significant obstruction. The result is reduced flow, increased pumping energy per litre delivered, and — in the worst case — complete air binding that stops flow entirely. This is why small-bore pipelines need dedicated air release, and it is why the Model 4001B exists: a DN25 single air release valve engineered for branch lines, service connections, secondary high points, pump casing vents, and anywhere a compact, energy-saving, easily installed air valve is the correct specification.

Product Overview

The Model 4001B is a DN25 single air release valve, PN16 rated, for water and neutral oil service. It employs a single float-operated orifice that automatically vents accumulated air at system operating pressure. The float is a solid-welded stainless steel 304 sphere — corrosion-proof, permanently buoyant, incapable of water-logging. The body is cast from EN-GJS-500-7 (GGG50) ductile iron with 100% internal and external fusion bonded epoxy coating (250 um DFT, spark-tested at 3 kV). Its DN25 connection enables direct threaded installation onto a pipe nipple, tank top tapping, pump casing vent port, or filter housing — no flange, no gasket, no bolting. The 4001B operates fully automatically on buoyancy alone: no power, no control wiring, no compressed air, no operator. When air accumulates, the float drops, the orifice opens, the air vents. When water rises, the float lifts, the orifice seals. This cycle continues silently, continuously, for the life of the pipeline. Manufactured by Shandong Huaze Valve Co., Ltd. (ISO 9001, since 1998), every 4001B is shell-tested at 24 bar, seat-tested at 18 bar, and verified for float operation before dispatch.