Backflow preventer

Product Overview

The Copper Threaded Backflow Preventer is a safety device used to prevent contaminated water from flowing back into potable water supply pipelines. It features a forged or cast body made of high‑quality brass (e.g., CW617N or HPb59‑1) with female or male threaded ends, specially designed for applications with high water safety requirements such as drinking water systems, boiler feed water, and the food industry. This device works through the coordinated action of two check valves and an intermediate relief chamber. Under any backflow or backpressure condition, it automatically discharges reverse water to the atmosphere, completely eliminating backflow contamination. Brass material offers excellent corrosion resistance and bacteriostatic properties, making this backflow preventer an ideal choice for anti‑backflow protection in residential and commercial water supply systems.

Product Structure

The Copper Threaded Backflow Preventer mainly consists of the following parts:

1. Body: High‑quality brass (forged or cast), threaded ends (female/male) conforming to DIN/ISO or NPT standards.
2. First Check Valve (inlet side): Spring‑loaded rubber‑seated check cartridge, allowing forward flow.
3. Second Check Valve (outlet side): Also spring‑loaded, forming dual sealing with the first check valve.
4. Intermediate Relief Chamber: Located between the two check valves, equipped with a relief valve (discharge port).
5. Relief Valve / Drain Device: Automatically opens when the intermediate chamber pressure rises abnormally (typically more than 0.14 bar above inlet pressure), discharging reverse water to atmosphere.
6. Test Cocks (optional): Usually provided at the relief chamber, inlet, and outlet for field performance testing.

Compact design, small footprint, directly installed on threaded pipe connections without flanges or welding.

 Function

1. Prevents Backpressure Backflow: When outlet pressure exceeds inlet pressure (backpressure condition), both check valves close, and the intermediate relief valve opens, draining any potential leakage and preventing contamination from entering the upstream.
2. Prevents Backsiphonage: When upstream supply pressure drops sharply (e.g., pipe burst), creating negative pressure, the relief chamber draws in air or discharges water, preventing downstream sewage from being siphoned back upstream.
3. Dual Sealing Redundancy: Two independent check valves provide redundant sealing. Even if one check valve slightly leaks, the relief valve in the intermediate chamber will activate, ensuring upstream water safety.
4. Visual/Audible Discharge Indication: Relief valve discharge is usually visible or audible, indicating abnormal conditions.
5. Easy Maintenance: Threaded connections allow easy disassembly for cleaning; internal cartridges are often replaceable.
   

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Working Conditions

1. Applicable Media: Potable water, tap water, food‑grade water, cooling water, makeup water for air conditioners, boiler feed water, grey water (non‑severe contamination).
2. Temperature Range: 0°C to +80°C (standard EPDM seals); high‑temperature version up to +110°C (silicone or FKM).
3. Pressure Rating: PN10, PN16 (maximum working pressure typically 1.0 MPa or 1.6 MPa).
4. Installation Position: Horizontal pipeline (discharge port facing downward); not to be installed upside down.
5. Typical Applications:

6. 1. Domestic water inlet pipes in residential buildings (preventing backflow from household to municipal mains)

   2. Boiler or solar water heater makeup systems

   3. Fire protection tank fill lines

   4. Industrial equipment cooling water systems (connected to drinking water lines)

   5. Food and beverage processing equipment water inlets

   6. Garden irrigation systems (preventing fertilizer/pesticide backflow)

Summary

The Copper Threaded Backflow Preventer, with its compact threaded design, dual check valves plus relief chamber, and reliable backpressure & backsiphonage protection, is the preferred safety device for preventing backflow contamination in potable water and residential water supply systems. Brass material combines strength and hygiene, while threaded connections allow quick installation without special tools. It effectively isolates downstream potential contamination sources (such as boiler water, cooling water, or fertilizer water), safeguards upstream water quality, and complies with domestic and international drinking water safety regulations. For applications requiring cross‑connection control in residential, commercial, or industrial makeup water systems, the Copper Threaded Backflow Preventer is an indispensable protective component.