Brass Horizontal Check Valve | Swing Backflow Preventer

Our Brass Horizontal Check Valve is an automatic non-return valve with precision-forged brass body and hinged swing disc, held closed by gravity and opened by forward medium pressure. It prevents reverse flow, reverse pump rotation and water hammer when pumps stop or upstream pressure drops, protecting downstream equipment. Swing design delivers ultra-low flow resistance when fully open, ideal for pump suction and high-flow lines. Available with soft or metal seals, threaded or flanged connections. Widely used in water supply, HVAC, fire protection, oil & gas and general industrial pipelines.

1.Gravity-closed Swing Disc: Hinged flapper disc swings on horizontal pin, closes by gravity only with near-zero cracking pressure (<0.01 MPa), ideal for low-pressure and gravity-flow systems. Disc swings fully out of flow path when open for ultra-low pressure drop.

2.Mandatory Horizontal Installation: Must be installed horizontally (standard) or vertical flow-up (acceptable); upside-down or vertical flow-down installation causes disc to stay open and fail to prevent backflow. Use vertical lift check valve for vertical flow-down pipelines.

3.Forged Brass Body: Precision-forged brass (C3770 lead-free / C3600 free-cutting / H62 / DZR dezincification-resistant), excellent corrosion resistance to water, mild acids, oils and gases, 30-60% lower cost than stainless steel check valves.

4.Zero-leakage Sealing: Precision-machined seat and disc with soft seal inserts (NBR/EPDM/PTFE) achieving Class VI zero leakage per API 598; optional metal-to-metal seal Class IV for high-temperature service. Reverse pressure self-energizes the seal.

5.Threaded / Flanged Ends: DN15–DN200, PN16, -20~180°C. Threaded NPT/BSP/G or flanged RF connections per GB/T/ANSI/EN/JIS standards. Optional spring-loaded version for faster closing.

6.Standards & Lead-free Option: Designed per GB/T 12235, ASME B16.34, API 594, 100% hydrostatic and reverse seal tested. ISO 9001, CE certified. Lead-free C3770 option with NSF/WRAS certification for potable water. 18-month warranty, OEM/ODM customization.

The Brass Horizontal Check Valve operates automatically with no external power: when forward medium pressure exceeds the weight of the disc, the disc swings upward on the horizontal hinge pin, opening the flow path; when forward pressure drops or reverses, gravity pulls the disc back down onto the seat, blocking reverse flow. The swing design allows the disc to move fully out of the flow path when open, delivering ultra-low flow resistance (clean ΔP ≤0.05 bar). Standard gravity version has near-zero cracking pressure; optional spring-loaded version provides faster closing with reduced water hammer. Must install horizontally for proper seating.

Water Supply & Drainage: Municipal water mains, building risers, pump discharge lines, prevents backflow when pumps stop, protects pumps from reverse rotation. Lead-free option for potable water systems.

HVAC & Heating: Chiller/boiler circuits, heat pumps, hydronic systems, prevents backflow in distribution lines, protects circulator pumps. EPDM/PTFE seals for hot water service.

Fire Protection: Fire sprinkler pump discharge, riser check valves, protects fire pumps from reverse rotation, maintains system pressure. Installed per NFPA requirements.

Water Treatment & Chemical: Water treatment plant pump discharge, RO pre-treatment, mild chemical process lines, prevents backflow contamination. PTFE seal for chemicals, SS disc/hinge pin for corrosive service.

Oil & Gas / Industrial: Light oil pipelines, compressed air, low-pressure natural gas lines, compressor discharge, prevents reverse flow and pressure surge, protects equipment from reverse rotation.

Every Brass Horizontal Check Valve undergoes rigorous quality control under ISO 9001 management system. Raw materials come with certified composition; C3770 lead-free brass verified to Pb≤0.25%. 100% hydrostatic shell test at 1.5×PN, reverse seal test (critical for check valves), hinge function test and dimensional inspection. Full material traceability for each unit. 18-month warranty.

Q1: Why must it be installed horizontally, and what if installed vertical flow-down?

A: The disc swings on a horizontal hinge pin and closes by gravity, so horizontal installation ensures proper seating. Vertical flow-down or upside-down installation pulls the disc off the seat by gravity, causing complete backflow failure. Vertical flow-up is acceptable but horizontal is most reliable.

Q2: What is the difference between swing check and vertical lift check valves?

A: Swing check: hinged disc, gravity closed, horizontal installation, ultra-low ΔP, but slams causing water hammer, hinge pin wears. Vertical lift: guided plunger + spring, vertical installation, fast controlled closing with low water hammer, but higher flow resistance and cracking pressure.

Q3: What pressure and temperature rating, and can it be used for steam?

A: Body rating PN16, overall temperature -20~180°C; NBR seal ≤80°C, EPDM ≤120°C, PTFE ≤180°C. Suitable for low-pressure saturated steam ≤10 bar with PTFE seal and SS hinge pin/disc; not for high-pressure or superheated steam.

Q4: The valve slams/bangs on pump stop (water hammer) - what to do?

A: Gravity swing checks naturally slam on rapid pump stop. Solutions: install VFD/soft starter to slow pump stop (most effective); specify spring-loaded swing check; replace with vertical lift spring check or silent check valve; add surge vessel/air chamber to absorb pressure spike.

Q5: Can it be used for potable drinking water, and is lead-free available?

A: Yes, with lead-free C3770 brass body (Pb≤0.25%), food-grade seals and SS hinge pin/disc. Optional NSF/ANSI 61, WRAS certification available. Standard industrial brass contains ~3% lead and must NOT be used for drinking water.

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