Rotary Valve Drive System

Rotary valve drive connections designed and manufactured by Polimak come in three different variations, the worm gear reducer connection, direct coupling connection and the chain drive connection. These drive connections are implemented to a rotary valve through a rotary valve rotor.

Worm Gear Reducer Drive Connection

A worm gear is the fundamental component of a worm gear reducer direct connection. It is a compact gearing equipment used for high motor speed reduction to produce low-speed output with high torque – hence the term ‘worm gear reducer’. The low-speed output is determined by the thread number on a worn and the number of teeth on a worm wheel. In other words, the output speed is based on the reduction ratio. Worm gears are used in various equipment including rotary valves. An electric drive motor and a worm gear reducer form a drive system (worm gear reducer drive) that is directly connected to a valve rotor shaft. This connection ensures reduced rotation of the rotor shaft inside the valve housing, thereby allowing smooth and controlled bulk material flow with  the system.

Worm Gear Reducer Drive Connection

Chain gear connection

The main component in a direct coupling drive connection is a coupling, also referred to as a shaft coupling. Shaft couplings are designed to transmit torque between a driving shaft and a driven shaft. They consist of two hubs, one fixed at the end of each rotating shaft. Torque is transmitted through these hubs. An electric drive motor and a driven machine (rotary valve) are directly connected using a shaft coupling. The coupling cannot reduce the motor’s rotating speed and for this reason, a worm gear reducer is used to ensure low-speed output. A direct coupling drive connection offers some of the following benefits; the absorption of mounting errors (shaft misalignment), vibration absorption during operation etc.

Chain Drive Connection

Chain Drive Connection

A chain drive is used for transmitting mechanical power from an electric drive motor to a driven shaft. It consists of a chain and two or more sprockets (two sprockets are typically used with rotary valves). The sprockets are attached to the drive motor shaft and the driven shaft (valve rotor shaft). The chain holes (pitches) fit over the sprocket teeth. Power is transmitted through the chain during operation. A worm gear reducer is used with chain drive connections because they cannot reduce the output rotating speed of a motor.

Direct Coupling Drive Connection


What is a drive system?

A drive system or sometimes called drive connection refers to a type of system or connection driving a machine during its operational duration.

What is Coupling?

A shaft coupling is a mechanical device that connects two rotating shafts for torque transmission from a driving shaft to a driven shaft.

How does a worm gear reducer work?

A worm gear consists of a shaft with spiral threads known as a worm and a toothed wheel known as a worm wheel (spur gear). A worm gear reducer is formed when the threads of a worm perpendicularly align to fit the teeth of a worm wheel. Torque is applied to the gear assembly via a worm pinion. As an electric motor applies a rotation force to the assembly, the worm’s threads push against the teeth of the worm wheel causing it to rotate. The rotation of the worm wheel applies a torque to the driven which turns at a speed related to the reduction ratio of the gear assembly.