INNOVATIVE

Rotary Valve

A rotary valve is a piece of bulk material handling equipment that regulates the flow of bulk solids by means of a rotating internal component that aligns with inlet and outlet ports.

Also known as an airlock feeder or airlock valve, it is used to regulate the flow of dry bulk solids from upstream equipment, such as storage silos, hoppers, and dust collection systems, to downstream systems like pneumatic conveying systems, belt conveyors, and screw feeders.
In this process, air pressure between the inlet and outlet is kept constant, which is achieved with the help of rotor blades. This sealing plays a critical role in systems where pressure differentials must be maintained, such as in pneumatic conveying or dust collection systems.

We manufacture rotary valves from durable materials such as cast iron, AISI 304 or AISI 316 stainless steel, and Hardox, ensuring resistance to abrasive, corrosive, or high-temperature materials.

Rotary valves are widely used across various industries, including food, chemicals, plastics, cement, agriculture, and others, for different bulk material handling processes.

Rotary Valves Components

Polimak’s product portfolio includes a variety of valve configurations designed to suit the properties of different bulk materials and the requirements of each application. The key components of the valve include:

• A valve body (housing) with an inlet port and an outlet port

• A rotor (shaft with blades)

• Two end plates (either outboard or inboard)

• A drive system

Housing

A rotary valve housing contains and secures the bulk material as it flows through the system during material handling. The housings are made from various materials, including cast iron, stainless steel, and Hardox.

We also provide special coatings for abrasive bulk materials and highly polished finishes for the food and dairy industries. The three housing configuration types available are flow-through, blow-through, and offset.

Rotor

Rotors operate as metering components in rotary valves, and their designs can vary. A rotor is also referred to as a rotor assembly, as it consists of a shaft and blades (also known as vanes) that are welded or cast together. It is the rotating component of the valve. Rotors can have different numbers of vanes, such as 6, 8, and so on.

The space between the vanes is called a rotor pocket. Generally, the lower the number of rotor pockets, the higher the pocket capacity.

End-plate

The rotary valve end plates prevent dry bulk material from flowing out of the rotor pockets and into the bearing area.

There are two types of end plate configurations: outboard and inboard bearing end plates.

Lip seals or gland packing are used to ensure the proper sealing and containment of the product.

Drive Systems

The valve’s drive system consists of a motor paired with a gearbox. Most rotary valves are driven by a reduction gearbox, which is powered by an electric motor. The reduction gearbox is used to receive a specific motor speed and produce a lower output speed.

Polimak offers three drive arrangements to accommodate different mechanical requirements and installation preferences:

• Worm gear reduction connection

• Chain gear connection

• Direct coupling connection

Bulk Materials Handled by Rotary Valves

The design of a rotary valve is tailored to suit the specific characteristics and properties of the dry bulk materials to be handled, ensuring an optimal and efficient process.

Different types of dry bulk solids demand specific valve designs. For materials that are corrosive, sticky, or cohesive, valves are often equipped with coated surfaces—such as non-stick coatings or polished stainless steel—to enhance performance and durability.

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ATEX Certified Rotary Valve

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Rotary Valve Drive Systems Polimak offers three different types of rotary valve drive connections, each suited to specific operational needs and installation requirements:• Worm Gear Reducer Connection• Direct Coupling Connection• Chain Drive ConnectionThese drive connections are implemented to a rotary valve by means of a rotary valve rotor. Worm Gear Reducer Drive Connection A worm […]

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Rotary Valve A rotary valve rotor is the rotating component within a rotary valve, a mechanical device used to regulate the flow of bulk materials from upstream to downstream equipment. The rotor’s rotation movement is powered by a drive motor connected to it. Various rotary valve drive connection options are available from Polimak to suit […]

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A rotary feeder is a type of valve whose primary function is to feed or meter dry bulk solids from an upstream device to a downstream device without necessarily maintaining a pressure differential. An airlock feeder is a valve that maintains a pressure differential while feeding or metering dry bulk materials into a downstream system.

• The blades of a rotary valve rotate inside the valve housing during operation.

• This rotation is driven by a motor.

• As the motor turns, the rotor pockets move through the valve.

• Dry bulk solids are supplied to the valve from upstream equipment through its inlet and settle in the pockets.

• The rotor continues to rotate and discharges the dry bulk solids through the outlet port.

• There are two types of rotation:

• Load side rotation: movement of the rotor pockets from the inlet to the outlet.

• Return side rotation: movement of the rotor pockets from the outlet port back to the inlet port.

Rotary valves find applications across numerous industries for a variety of industrial processes. They serve several key purposes, including:

• Controlling the flow of dry bulk solids

• Feeding downstream systems

• Maintaining a pressure differential between upstream and downstream equipment
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During the handling of bulk solids in powder or granule form, dust may be released into the atmosphere, which is harmful to both health and the environment. Dust collection systems and jet pulse filters are used to prevent these emissions from industrial processes. Storage silos, pneumatic conveying systems, mechanical conveying systems, production lines, and loading and discharging systems are key areas involved in handling powder and bulk solids. A wide range of filters and dust collection systems are available, depending on the physical properties of the dust and the characteristics of the bulk solid handling process…

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These valves are typically actuated by pneumatic actuators and are used to automatically open and close the product flow to discharge material to downstream equipment.
Installed below silos or hoppers, these valves are used for maintenance operations of equipment such as rotary valves, screw feeders, etc., that are positioned below the butterfly valve.
These valves are typically actuated by pneumatic actuators and are used to automatically open and close the product flow to discharge material to downstream equipment.
In this design, the butterfly valve is sandwiched between two flanges. Rubber sealing at both faces of the valve provides a tight seal between the flanges and the wafer butterfly valve.
One side of the valve has a bolted flange connection, while the other side features a built-in short pipe designed for fixing a flexible sleeve.
These valves have bolted flange connections on both sides, making them suitable for installation on silos, hoppers, screw feeders, and similar applications.
Bulk tanker trucks or open trucks can be filled with powdered materials delivered within FIBC bags. These systems generally consist of bulk bag discharging station, mechanical or pneumatic conveyor and loading bellow. Big bag discharge station transfers the bulk solid from big bag to conveying system. Conveying system transfers it to truck loading area. And loading bellow is used to fill tanker truck without any dust emission. Since truck loading operations are done within limited time, high capacity big bag discharge systems and bulk material conveying systems are used. For short distances, screw conveyors are preferred to transfer material from big bag discharge station to truck loading chute. For long conveying distances, pneumatic conveying systems provide better service. There may exist a storage hopper or silo above bulk truck loading bellow to compensate material flow between inlet and outlet. Bulk bag discharge and truck filling systems have automatic control system that monitors product level in truck and operates all equipment accordingly. Optional weighing system can be added to measure the amount of material that is filled to truck.
Big bag discharge systems can deliver dry bulk solids in powder and granular form to weighing and batching systems. The loading hopper of the weighing system should remain full during dosing and batching. Big bag discharge systems can monitor the product level in the loading hopper and maintain a constant level automatically. Depending on the dosing speed and conveying distance, mechanical conveying systems or pneumatic loading systems may be used. Dust collectors can be employed to prevent dust emissions during hopper loading, especially for materials with high dust content.
Dry bulk packaging systems are used to fill powdered or granular materials into bags, drums, jars, sacks, etc. Bulk materials delivered in big bags must be transferred to packaging machines without interruption. The loading hopper of the packaging system should remain full during the filling and packaging process. Big bag discharge systems can monitor the product level in the loading hopper and maintain a constant level automatically. Depending on the packaging speed, mechanical conveying systems or pneumatic loading systems can be selected. Dust collectors can be used to prevent dust emissions during hopper loading, especially for materials with high dust content.
Mixer automation systems are used to mix dry bulk solids according to specific recipes. Raw materials delivered in FIBC bags can be transferred to mixing units through a combination of conveying equipment and bulk bag discharge systems. Depending on the type of application, pneumatic conveying or mechanical feeding systems can be used to fill mixers. Big bag discharge stations can be manufactured with built-in dosing systems. The amount of raw material to be loaded into the mixer is automatically controlled with the help of a weighing and dosing system. Dust collectors can be used to prevent dust emissions during the mixer filling process.
Bulk material stored in big bags can be automatically filled into small bags. Big bag discharge systems come with optional built-in bag filling units. For low filling capacities, these units are installed below the big bag discharge hopper, providing a practical and cost-effective solution. Both big bag discharging and bag filling operations can be handled by a single, compact system. For higher bag filling needs, bag filling machines are installed near the bulk bag discharge stations. Pneumatic conveying systems or mechanical conveyors can be used to transfer bulk material from the FIBC bag discharge station to the bag or sack filling system.
Mechanical conveyors can be used for silo loading from big bag discharge stations. Screw feeders, bucket elevators, rotary valves, or chain conveyors are connected to big bag discharge stations to fill silos. The selection of conveying equipment directly depends on the conveying distance, height, transferred material, and capacity. Bucket elevators are preferred for high silos, while screw feeders are preferred for shorter silos and short distances. The big bag discharge system can be installed on top of the silo for faster filling. In this case, rotary valves or butterfly valves are better choices as they provide simple flow control. Dust collection systems may be required depending on the dust content of the bulk solid. During silo loading, air content in the silo escapes to the atmosphere and carries some dust along with it. Vacuum fans and jet filters in dust collectors prevent dust emissions into the environment. The collected dust is sent back to the silo, thus preventing product loss.
Pneumatic conveying systems installed after bulk bag discharge units transfer bulk material through conveying pipelines to fill silos. This configuration is useful in applications where high transfer rates and long conveying distances are needed. In production lines where raw materials are stored in warehouses far from storage silos, bulk bag discharge stations can be installed close to the warehouses, and pneumatic conveying systems are used to fill silos from long distances. This design reduces the need for forklifts and cranes for bulk material transfer on the production site and increases overall efficiency.

Pneumatic conveying systems used for silo loading utilize blower pumps or compressors. Motor power, pipeline diameter, and equipment selection depend on the type of bulk material, transfer distance, silo height, and transfer capacity. Level sensors, jet filters, and other equipment are installed on storage silos to ensure the proper operation of the silo filling system.
Pneumatic conveying systems installed after bag dump units transfer bulk material through pipelines to fill silos. This configuration is ideal for applications requiring high transfer rates and long conveying distances. In production lines where raw materials are stored in warehouses far from storage silos, bag dump stations can be installed close to warehouses, allowing pneumatic conveying systems to transport materials over long distances. This design reduces the excessive use of forklifts and cranes for bulk material transfer within the production site, improving overall efficiency.

Pneumatic transfer systems used for silo loading utilize blower pumps or compressors. Motor power, pipeline diameter, and equipment selection depend on factors such as the type of bulk material, transfer distance, silo height, and transfer capacity. Level sensors, jet filters, and other equipment are installed on storage silos to ensure the proper operation of the silo filling system.
Mechanical conveyors can be used for silo loading from bag dump stations. In this configuration, screw feeders, bucket elevators, rotary valves, or chain conveyors are connected to bag dump stations to fill silos. The selection of conveying equipment depends on factors such as conveying distance, height, material properties, and capacity. Bucket elevators are preferred for high silos, while screw feeders are ideal for shorter silos and short distances. Bag dump systems can be installed on top of the silo for faster filling. In such cases, rotary valves or butterfly valves are better choices as they provide simple flow control.

Dust collection systems may be required depending on the dust content of the bulk solid. During silo loading, air inside the silo escapes to the atmosphere, carrying dust particles with it. Dust collectors equipped with a vacuum fan and jet filter capture airborne dust. The collected dust is returned to the silo, preventing product loss and ensuring a cleaner environment.
The inlet skirt is an optional feature designed to extend the lifespan of the flexible connector sleeve. Its upper portion is attached to the outlet port of the upstream equipment and extends down into the bin activator’s inlet port. The primary function of the inlet skirt is to serve as a protective shield, safeguarding the flexible connector seal from wear and damage.
A vibratory motor is externally mounted to the bin activator. When powered, the motor generates vibrations that facilitate a steady flow of dry bulk materials within the system. Depending on the application requirements, one or two vibratory motors can be installed externally.
To accommodate a bin activator, the cone of a silo must be shorter than usual, resulting in a wider outlet. A flange supplied with the bin activator is separately welded to the silo’s outlet, slightly above the opening, at the production site. Once installed, the vibrating bin discharger is securely bolted to the flange, ensuring a stable and reliable connection.
Special spring suspension links and an engineered polymer seal work together to create a flexible connection between a vibrating bin discharger and the equipment positioned above it.

The proper design and installation of the polyurethane seal prevent it from slipping off and ensure a secure seal, eliminating the risk of dry bulk material leakage. Additionally, the seal offers high stress resistance and long-term durability, withstanding stresses caused by motor vibrations, pressure conditions, and other operational factors.

Externally installed spring suspensions provide full resilience to the vibrations of the cone head. They ensure that the generated vibrations affect only the cone itself rather than the upstream equipment structure.
An internally tapered, conical-shaped baffle plate is positioned at the center of the bin activator’s diameter. The baffle is rigidly attached to the equipment body using structural steel components. It facilitates bulk material flow from upstream equipment by directly inducing vibrations into the material.

A secondary deflector plate reduces the weight of the bulk material in the lower portion of the bin activator by acting as a wedge beneath the material, directing it around the areas adjacent to the cone’s surface.

Polimak baffle plates are available in various configurations, including convex and cone plates, and in different angles (15°, 30°, 45°, or even 60°) depending on the flow characteristics of the handled bulk material and the specific application requirements.