Gearbox - MO-Range | Alfa Gear

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

ALFA Gear MO Range Quarter-Turn Gearbox

The ALFA Gear MO Range is a worm gearbox for 1/4-turn valves, equipped with manual override. Designed for installation between double-acting or spring-return pneumatic actuators and valves, it enables manual operation of automated 90° valves without actuator removal, supporting process safety and maintenance requirements.

Technical Specifications

Sizes: MO15, MO35, MO75, MO200, MO350, MO550, MO850
Output torque: 150 to 8,500 Nm
Gear ratio: 1:38 to 1:408
Operating angle: 0–90°, adjustable ±5°
Ingress protection: IP67
Temperature range (Alfa quarter-turn series): -50 to +150 °C
Valve and actuator interface per ISO 5211, sizes F05/F07 to F16/F25

Construction

Body, cover, flange, worm rack, and quadrant are ductile cast iron JS1030. Worm shaft: C45 carbon steel. Input shaft: SS304. Couplings: A2 stainless steel. Sealing: NBR70. Lubrication: Lithium EP2.

Manual Override Operation

Manual override enables safe opening or closing when pneumatic actuation is unavailable or during maintenance. Optional 3/2 relief valve allows automatic air venting to prevent actuator backpressure during manual operation.

Installation

Valve and gearbox must be fully closed prior to assembly. Verify bolt cycle, stem/bore alignment, use of A2/A4 fasteners, and sealing at interfaces to limit moisture ingress. Set screws adjust open/close stops.

Applications

Suitable for ball, butterfly, plug valves, and dampers in water, air, steam, auxiliary gas networks, water treatment, and industrial isolation lines. Selection based on valve torque, ISO 5211 flange, actuator type, and manual override requirements.

FAQ

When is MO selected over a standard gearbox?
When a pneumatic actuator is present but manual intervention is required in case of air loss or for maintenance operations.

What is checked during maintenance?
Relief valve, IP67 sealing, set screws, handwheel, coupling, valve-actuator alignment, and increased manual torque.

Datasheet and documents

Materials & Dimensions

Description

Manual Override quarter turn Gearbox range suitable for mounting between a double or single acting pneumatic actuator and valve.

Available with optional 3/2 relief valve to relief air automatically from the system.

7 sizes · up to 8.500Nm Torque range · IP67 Enclosure · Insert system · Optional 3/2 Relief valve · Stainless Steel Inputshaft

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.