Description

Rotary Valve for Powder Discharge

The Rotary Valve transfers powders, granules and collected dust from storage or processing equipment into a downstream conveying or receiving system. A multi-vane rotor carries material through the housing in successive pockets, providing continuous discharge while the shaft rotates.

The YJD series includes two connection arrangements: YJDA with square flanges and YJDB with round flanges. Both use the same basic rotary feeding principle, with different mounting dimensions to suit the equipment interface.

An electric gearmotor drives the rotor through a reduction assembly. The valve is suitable for compatible dry bulk material applications beneath silos, hoppers, cyclones and dust collectors. Where pressure separation is also required, the rotor clearance and sealing construction must be matched to the intended airlock duty.

YJDA and YJDB Connection Designs

The choice between YJDA and YJDB begins with the equipment connection rather than the motor or rotor appearance.

Both configurations use a pocketed rotor inside an enclosed housing. Their flanges, mounting dimensions and available installation envelopes differ, so a similar internal opening does not guarantee that the two types are directly interchangeable.

For a replacement unit, the existing flange layout should be checked before selecting the model.

Technical Specifications

The final rotor design, material-contact components, gearmotor and sealing arrangement should be selected according to the material and operating requirements.

Rotor and Gearmotor Operation

The rotor is divided into pockets by a series of vanes. As the shaft turns, material enters the pockets beneath the inlet, moves around the housing and is released through the lower outlet.

The gear reducer lowers the motor speed to the rotational speed required by the rotor. The drive must provide sufficient torque to overcome resistance from the material and internal moving components.

Discharge capacity depends mainly on rotor pocket volume, rotational speed, material bulk density and how effectively the pockets fill and empty.

A larger valve or faster rotor does not automatically produce a proportional increase in throughput. Fine powders, cohesive materials and larger particles can behave differently during filling and discharge.

For this reason, the required feed rate should be considered alongside the actual bulk material rather than estimated from flange size alone.

YJDA Square-Flange Dimensions

The YJDA type uses square mounting connections. The dimensions below identify the corresponding model geometry, including flange dimensions and the overall installation envelope.

All dimensions are in millimeters. Symbols correspond to the YJDA dimensional drawing.

Additional YJDA Dimensions

The two 400×600 configurations have different external dimensions. The full installation measurements should be used to distinguish them.

YJDB Round-Flange Dimensions

The YJDB configuration uses circular flange connections for corresponding equipment outlets.

Its flange diameters differ from the square mounting arrangement used by YJDA. The overall drive dimensions must also be checked when replacing an existing valve.

All dimensions are in millimeters. ØA, ØB and ØC indicate diameter dimensions.

Additional YJDB Dimensions

Dimensional Note: Flange dimensions, drilling patterns and installation clearances should be checked against the final drawing for the selected configuration before ordering.

Rotary Feeding and Airlock Requirements

A Rotary Valve can be selected for continuous material feeding or for an application that also requires a degree of air separation.

The distinction matters.

In a gravity discharge arrangement, material passes from a silo or hopper into the rotary pockets and then into the equipment below.

In a dust collection or pneumatic conveying system, the valve may operate between sections with different pressures. Air movement through the rotor clearances can then become an important part of the operating conditions.

For applications requiring airlock performance, the valve should be selected according to:

• System pressure differential

• Permitted air leakage

• Material characteristics

• Rotor-to-housing clearance

• Shaft sealing arrangement

• Required discharge capacity

A standard rotary feeder should not automatically be treated as a pressure-rated or completely airtight valve.

Where positive material isolation is required for maintenance, a separate shut-off device, such as a suitable VFS Butterfly Valve, may be included in the system.

Material Compatibility and Installation

The material being handled affects the rotor, housing and sealing requirements.

Cement, fly ash and fine mineral powders may require particular attention to shaft sealing and material accumulation. Abrasive particles can increase wear on the rotor and housing surfaces, while moisture-sensitive materials may become difficult to discharge if they begin to cake.

The valve should be configured around the actual material characteristics rather than assuming that one rotor and sealing arrangement is suitable for every powder.

Typical installation applications include:

• Cement and fly ash discharge systems

• Dust collector and cyclone outlets

• Powder storage silos and hoppers

• Mineral processing equipment

• Chemical powder handling systems

• Grain and flour handling where appropriate construction and hygiene requirements are met

• Compatible pneumatic conveying systems

During installation, the inlet and outlet connections should align with the adjoining equipment without applying unnecessary stress to the valve housing.

Enough clearance must also remain around the electric motor, gear reducer and end covers for inspection and maintenance.

Model Selection and Ordering

The correct YJDA or YJDB configuration depends on both the material-handling requirement and the mechanical connection.

For a new installation, the expected discharge rate, bulk density, material characteristics and equipment connections should be established before selecting the rotor and drive arrangement.

For replacement work, the existing valve dimensions and motor position must also be considered.

TONGJINJIN supplies Rotary Valves for dry bulk material feeding and discharge equipment.

YJDA and YJDB configurations provide different connection arrangements for silos, hoppers, dust collectors and related systems. Rotor construction, drive requirements and material-contact components can be matched to the selected application.

OEM and ODM services are available for equipment manufacturers, bulk material handling suppliers, distributors and maintenance projects.

Frequently Asked Questions About Rotary Valves

How do I choose between a YJDA and YJDB Rotary Valve?

Start with the equipment connection. YJDA uses square flanges, while YJDB uses round flanges. Check the opening dimensions, bolt-hole arrangement and available installation space before selecting the model. Similar opening sizes do not guarantee interchangeable mounting dimensions.

What information is needed to select the discharge capacity?

The most useful information is the required material flow rate, bulk density and material characteristics. Rotor pocket volume and rotational speed affect volumetric discharge, but actual output also depends on how completely the material enters and leaves the pockets.

Can a Rotary Valve operate beneath a dust collector under negative pressure?

It can be considered for this duty when the construction is suitable for the system conditions. The expected pressure difference, allowable air leakage, material and discharge rate should be provided so the rotor clearances and sealing arrangement can be evaluated.

Can a Rotary Valve handle abrasive or moisture-sensitive powders?

It depends on the rotor and housing materials, internal clearances and operating conditions. Abrasive materials may increase wear, while moisture-sensitive powders can accumulate or bridge inside the rotor pockets. The actual material characteristics should be checked before selection.

Does stopping the gearmotor completely isolate the material and airflow?

No. A stopped rotor should not be considered a guaranteed positive shut-off. Material or air may still pass through internal clearances depending on the valve construction and system conditions. A separate isolation device may be necessary where complete shut-off is required.

What should be checked when replacing an existing Rotary Valve?

Compare the flange dimensions, mounting-hole positions, overall installation height, drive orientation and available maintenance space. The replacement must also suit the required discharge capacity and material. Existing drawings or photographs are useful when the original model cannot be identified.