Gearbox - S-Range | Alfa Gear

Name: Gearbox - S-Range | Alfa Gear
Brand: Alfa Gears
SKU: Gearbox - S-Range | Alfa Gear

ALFA Gear S Range Quarter-Turn Gearbox

ALFA Gear S Range is a manual worm gearbox designed for quarter-turn (1/4 turn) operation of butterfly valves, ball valves, plug valves, dampers, and other 90° rotary valves. The series is engineered for heavy-duty service, constructed from ductile cast iron JS1030, with standard IP68 ingress protection and available in 14 sizes up to 32,000 Nm output torque.

Technical Specifications

Operating angle: 0–90°, with stop adjustment ±5°.
Torque range: 250–4,500 Nm for S25–S450.
With spur stage: 4,000–32,000 Nm for S400/2–S3200/10.
Gear ratios: 1:34 to 1:798, depending on size.
Valve interface: EN ISO 5211, from F05/F07 to F40.
Temperature range (general series): -50 to +150 °C.

Construction and Materials

Body, cover, position indicator, and quadrant are ductile cast iron JS1030. Worm is C45 carbon steel, shaft SS316, fasteners A2 stainless steel, sealing NBR70, lubrication Lithium EP2. Larger models use reduction gears in C45.

Selection Logic

Selection is not based solely on valve DN. Consider:

Maximum valve torque at differential operating pressure
Seat type and sealing class
Potential for stiction or deposits
Available handwheel size and permissible operator force
Stem/bore/key dimensions and ISO 5211 flange

Installation

Valve and gearbox must be in fully closed position prior to assembly. Check bolt circle alignment, stem/bore match, use of A2 or A4 fasteners, and seal the interface with gasket or liquid sealant to prevent moisture ingress.

FAQ

When to select S Range over E Range?
When ductile cast iron construction, standard IP68, or torque up to 32,000 Nm is required.

What is checked during maintenance?
Open/close stops, enclosure sealing, handwheel, coupling, fastener corrosion, and increase in operating torque.

Datasheet and documents

Description

Heavy duty Ductile cast Iron (GGG40) quarter turn gearbox range. Standard IP68 enclosure and available in 14 sizes up to 32000Nm.

Alfa Insert system available. Optional with heavy duty Marine paint systems.

Larger sizes on request.

14 sizes · up to 32.000Nm · IP68 Enclosure · Alfa Insert system · Optional C3, C4 or C5M Coating

GENERAL TECHNICAL INFORMATION

Application

Alfa-Series quarter-turn worm gearboxes are applied to ball valves, butterfly valves, dampers and other 90° rotary valves. Alfa Gears hand wheels are with a variety models for optimal operation.

Operating Enviroment

Alfa Gears quarter-turn Worm gearboxes are with good mechanical quality and steady operating performance which apply to deal with variety climate and temperature. We strive to develop Alfa Gears valve gear operators to meet higher demands in the market.

Factory Standard

Enclosure: IP67 Standard (IP68 on request) Working Temperature: From -50°C to 150°C (-4°Fto248°F) Painting: Black RAL 9005, or according customer specification

Connect with Valve

The flange connecting to valve is according to EN ISO5211 or DIN3210 (Customization). including Sintered coupling system for various shaft connections. Please click on our link to download the Alfa Gears Dimensions or Alfa Gears Materials specification.