Rotary valves are applied for powder discharge and therefore an important component in the drying plant. GEA Process Engineering has developed an extensive range of standard designs to meet the various industry specific requirements.

Design highlights
Rotary valves are designed for a continuous discharge operation of powders and granulates. The valves consist of tapered housing and rotors with gear and motor drive. The tapered design allows for quick and precise adjustment of clearances between the rotor and housing. The required clearance depends upon the nature of the particulate material (e.g. powder, granules, pellets, and agglomerates), operating temperatures and pressures.

The special design allows for easy access for cleaning and no special tools are required for maintenance. The rotary valves are suitable for applications designed for the discharge of particulate matter from dryers and solids handling equipment.

Two sizes – four designs
The valves are manufactured in two sizes (200 and 347 mm) with four different designs as stated below:

  • Standard design
    The rotor can be quickly accessed and removed by opening the side-hinged end cover. The cover facilitates easy access for cleaning all powder contact areas.

  • Air-purged (AP) design
    In addition to the above mentioned standard design, AP design also permits a small amount of air or inert gas into the double oil seal ring to purge the gap between the sealing lip and shaft. This design is used when extra precautions must be taken to prevent any trace of a lubricant passing down the shaft from the gearbox. 

  • Gastight (GT) design
    Based on the AP design, this gas-tight design is fitted with a fixed end cover (fastened by Allen screws) for additional safety. This design is pressure tested at 0.5 bar and is used in closed-cycle (inert gas) spray dryers and fluid bed dryers.

  • Sanitary (SA) design
    For sanitary applications, the drive of the standard design is modified so that the drive unit is separated from the product contact area. It is impossible for lubricant to contaminate the product. Oil seals can be inspected during operation, since the shaft between drive and valve housing is visible from the outside. All product contact seals can be replaced without removing the drive unit from the valve housing. Product contact surfaces are self-draining for a better CIP operation , and the finish is at least Ra 1.6 Ám.

Standard features:

  • Compact, modular design
  • No lodgment points
  • Constructed of cast 316 stainless steel body and end covers
  • All internals surfaces are fully machined with all welds ground smooth and polished to a Ra 2.5 Ám finish
  • All external surfaces are fully machined with polished finishes available upon request
  • Quick-release stainless steel rotor for fast and easy accessibility and cleaning
  • Direct-coupled drive, making the unit more compact and minimizing external cleaning
  • Outboard bearings for non-contamination
  • Food grade seals and packing
  • Sizes 200 and 347 mm


  • For use with granular products and pellets
  • For gravity discharge and metering
  • For feeding pneumatic conveying systems

Drive specifications:

  • Flanged motor (6 pole, 0.37 kW) special design: 920 rpm at 50 Hz or 1100 rpm at 60 Hz
  • Foot-mounted motor with above specification (optional supply)
  • Motor speed control via frequency control equipment (optional supply)
  • Gear box is a planetary design, rotor speed 25 rpm at 50 Hz and 30 rpm at 60 Hz

Materials of construction:
The rotary valves are supplied in two material combinations as stated below:

Material code

Material specification





Stainless steel



Stainless steel

Stainless steel

Rotary valve specifications:

Rotary valve application type Material code-valve size


Air-purged (AP) SST-200/AP
Gas Tight (GT) SAT-200-B/GT
Sanitary (SA) SST-347-B/SA

B: Bracket for foot mounted motor
T: Taper Housing


  • Body & End Covers: Stainless Steel AISI 304, AISI 316, AISI 904L
  • Flanges: Round, Square
  • Rotor: Teflon Coated, other stainless steel material such as AISI 304, AISI 316, AISI 904L
  • AISI 304, AISI 316, AISI 904L
  • Shaft Seals: Air Purge
  • Motor: Foot mounted, Flange mounted