Ammonia Valve Series

What materials are used for ammonia valves?

Ammonia valves require materials compatible with NH3 (ammonia) and its low-temperature liquid phase (-33°C for liquefied ammonia at atmospheric pressure). TANGGONG manufactures ammonia valves from: (1) LCB/LCC — low-temperature carbon steel for liquefied ammonia service down to -46°C; (2) CF8/CF8M (SS304/SS316) — austenitic stainless steel for corrosive ammonia solutions and gaseous ammonia; (3) WCB — carbon steel for gaseous ammonia above -29°C (with NACE compliance for trace impurities). All soft goods (seals, gaskts) are ammonia-compatible: PTFE, graphite, or specialized ammonia-resistant elastomers.

Why do ammonia valves require low-temperature rated steel (LCB/LCC)?

Liquefied ammonia (NH3) has a boiling point of -33.34°C at atmospheric pressure. When liquefied ammonia expands through a valve or experiences pressure drop, it can cause severe local cooling (Joule-Thomson effect) down to -46°C. Standard carbon steel (WCB) undergoes ductile-to-brittle transition at approximately -29°C, risking catastrophic brittle fracture. LCB (low-temperature carbon steel, impact tested at -46°C) and LCC (low-temperature carbon steel, impact tested at -46°C) maintain ductility and toughness at these temperatures, preventing valve body rupture.

What is the difference between an ammonia valve and a standard industrial valve?

Ammonia valves differ from standard valves in: (1) Body material — LCB/LCC low-temperature steel vs. WCB for standard valves; (2) Soft goods — ammonia-compatible seals (PTFE, graphite) vs. standard NBR/EPDM; (3) Design pressure/temperature — based on NH3 phase diagram (liquefied vs. gas); (4) Cleaning — ammonia valves require degreasing and ammonia-compatibility certification; (5) Testing — additional low-temperature operability test and ammonia leakage test; (6) Seat design — frequently renewable seat for easy maintenance in fertilizer plant service.

Can TANGGONG supply ammonia valves for refrigeration systems?

Yes. TANGGONG manufactures ammonia valves specifically for industrial refrigeration systems using NH3 as refrigerant. These include: (1) Ammonia gate valves for main liquid ammonia lines; (2) Ammonia globe valves for refrigerant flow regulation and expansion control; (3) Ammonia check valves for compressor discharge and pump protection; (4) Ammonia safety relief valves for overpressure protection of receivers and condensers. All refrigeration-grade ammonia valves are supplied with LCB/LCC bodies and ammonia-compatible seals, certified for -46°C service.

What are the testing requirements for ammonia valves?

TANGGONG ammonia valves are tested per: (1) Shell test — 1.5× pressure rating, helium or air soak test; (2) Seat leakage test — ISO 5208 Rate A (bubble-tight) or Rate B; (3) Low-temperature operability test — at -46°C with liquefied ammonia simulant; (4) Ammonia compatibility test — seal/gasket material immersion test in NH3; (5) Fire-safe test (for applicable designs) — API 607; (6) MTR (Material Test Report) — impact test results at -46°C for LCB/LCC. Third-party inspection (TUV, SGS, BV) is available on request.