Pressure reducing valve - PREDU | ARI

ARI-PREDU Direct-Acting Pressure Reducer

The ARI-PREDU is a self-acting proportional pressure reducer designed to lower high inlet pressure to a reduced outlet pressure. The downstream pressure is transmitted to the DMA diaphragm actuator via an impulse line; as downstream pressure increases, the valve moves towards closure. No auxiliary energy is required.

Technical Specifications

• DN15–DN150, flanged connection according to DIN.
• PN16, PN25, and PN40 versions, depending on body material.
• Body materials: EN-JL1040, EN-JS1049, 1.0619+N.
• Downstream setting ranges: 0.2–0.6 / 0.5–1.2 / 0.8–2.5 / 2–5 / 4.5–10 / 8–16 bar(g).
• Standard Kvs 3.2 to 280 m³/h, with reduced Kvs for small flow rates.
• Leakage class I according to DIN EN 1349 / DIN EN 60534-4.

Actuators and Sealing

Available actuators DMA 400, 250, 160, 80, and 40, with EPDM diaphragm up to +130°C or NBR up to +100°C. Shaft sealing is achieved with a stainless steel bellows, with an option for secondary stem sealing. Metal or soft PTFE sealing for seat/cone up to 200°C.

Media and Applications

Suitable for Group II fluids according to PED 2014/68/EU: steam, neutral gases, vapors, and neutral liquids. Used in steam reduction stations, HVAC networks, industrial water, compressed air, and auxiliary process networks. For steam or hot liquids, a water seal pot is required in the impulse line when temperature exceeds diaphragm limits.

Selection and Installation Points

The impulse line should be installed at least 10 × DN or 1 m downstream of the valve. Upstream filter, inlet/outlet pressure gauges, isolation valves, bypass, and safety valve on the downstream side are recommended. Selection is based on p1, p2, flow rate, Kvs, temperature, body material, and permissible pressure drop.