SHUANGLIN VALVE | Brass Backflow Preventer, DN15–DN65

A standard check valve stops water from flowing backward — but when the water on the other side of that valve is contaminated, "usually works" isn't good enough. Drinking water protection calls for redundancy, and that's exactly what SHUANGLIN VALVE's backflow preventer is built to deliver: two independent check modules working together, so a single point of failure can't compromise the potable water supply.

Why One Check Valve Isn't Enough for Drinking Water

A single check valve can fail — debris can lodge in the seat, a spring can wear out, or the disc can simply stick partway open. In a general-purpose application, that's an inconvenience. In a line protecting drinking water from a garden hose connection, an irrigation system, or a commercial process line, it's a contamination risk. A backflow preventer addresses this by using two independent check valves in series: if one fails, the second still blocks reverse flow, giving the system a genuine fail-safe rather than a single point of possible failure.

Modular, Serviceable Design

Each check module in this assembly is housed in its own removable cartridge, so individual check valves can be inspected, tested, or replaced without dismantling the entire unit — a significant advantage for facilities that need to comply with periodic backflow testing requirements. The body sections connect together in a modular fashion, as shown, allowing configurations with multiple branch outlets to be built from standardized components rather than requiring a custom-cast body for every layout.

Specification Overview

SHUANGLIN VALVE manufactures this backflow preventer in solid brass across the DN15 to DN65 size range, with threaded connections sized to integrate with standard potable water piping. Each check module operates independently and automatically, requiring no external power, and is rated for continuous-pressure applications.

Where It's Required

• Points where a potable water supply connects to irrigation, fire sprinkler, or non-potable systems

• Commercial kitchen and food processing equipment connections

• Boiler and heating system make-up water lines

• Laboratory and medical equipment water connections

• Any cross-connection point where local plumbing codes require backflow protection

Ordering Information

• Payment: T/T (Bank Transfer)

• Stock Items: Ships within 7 days

• Custom Orders: 30 days production time

• Logistics: Sea or air freight, with customs clearance assistance

Warranty & Customization

SHUANGLIN VALVE backs every backflow preventer with a 1-year warranty against manufacturing defects, including free repair or replacement where applicable. OEM/ODM services are available for custom port configurations, thread types, and private-label packaging on bulk orders.

Frequently Asked Questions

How is a backflow preventer different from a standard check valve? A standard check valve uses a single mechanism to block reverse flow, which can fail without warning. A backflow preventer uses two independent check valves in series, so if one fails, the second still provides protection — a level of redundancy required for protecting potable water.

Can the internal check valves be tested or serviced individually? Yes. Each check module sits in its own removable cartridge, allowing individual inspection, testing, or replacement without removing the entire assembly from the pipeline.

Does this device require regular testing? Many jurisdictions require periodic testing of backflow prevention devices, particularly in commercial and cross-connection applications. Check your local plumbing code for specific requirements in your installation.

What sizes and configurations are available? SHUANGLIN VALVE produces this backflow preventer from DN15 to DN65, including multi-outlet modular configurations. Contact us with your layout requirements for a tailored quotation.

Contact SHUANGLIN VALVE's sales team for a detailed quotation, technical drawings, or samples.