VL-2R - Motorized adjustable port valves

Description

The VL‑2R series consists of motorized adjustable-opening valves designed for regulating fluid flow—specifically non‑aggressive gases compliant with EN 437—in low‑pressure combustion system pipelines. These valves adjust flow via a primary adjustment shaft, driven by an ESA SERIO electric actuation system, and feature a front graduated indicator showing OPEN/CLOSED status. A secondary adjustment shaft allows operators to fine‑tune the internal passage for precise flow regulation.

The valves are suitable for maximum working pressures up to 450 mbar at 60°C, with operational temperatures from −20°C to +60°C and leakage below 1%. They are available in threaded versions (Rp ½″ to 2″, ISO 7/1) and flanged versions (DN65–DN150), with NPT threading upon request. Rotation is 0–90°, and the body connection follows ISO 5211 (F05/F07).

Construction materials include aluminum valve body, OT58 shaft, AISI 303/316 adjustment screws, and AISI 304/Fe360 levers, with O‑ring sealing. Depending on configuration, control is possible through:

• SERIO TPF (on/off/min/max),
• SERIO FLT (3‑point floating),
• SERIO PRP (proportional).

The manual includes complete flow‑rate charts for air, NG, and LPG, plus formulas for calculating the capacity for other gases using density corrections. Sizing guidance specifies maximum recommended pipeline velocities (<20 m/s) to limit noise and pressure drops. Procedures for converting between m³/h and Nm³/h are also provided for accurate system design.

Installation guidelines cover correct flange alignment, prevention of foreign‑body ingress, appropriate torque sequences, and required straight pipe sections (≥2×DN). The valve can be mounted horizontally or vertically but not upside down. Calibration varies by model: VL‑2R‑D units are set through actuator stroke, while VL‑2R‑L units rely on lever and joint adjustments.

Maintenance instructions include periodic gasket checks, motion verification, calibration control, and internal cleaning. The valves are classified as regulating—not safety—devices, and must not be used for fuel shutoff.