STANDARD CAST IRON ROTARY AIRLOCK VALVE

Industrial pneumatic isolation unit with a high-density GG25 grey-cast-iron body

A high-precision pressure barrier that, on the pneumatic conveying, filtration and silodischarge lines of flour, semolina and feed mills, separates from the air the bulk raw materials (flour, semolina, bran, grain, etc.) conveyed by a pressure or vacuum stream and transfers them to the next process. Owing to its high-strength GG25 grey-cast-iron body, it keeps the static and dynamic air losses across the system to a minimum, ensuring stable pneumatic-line operation with maximum energy saving.

WORKING PRINCIPLE

Sub-pneumatic-line and sub-cyclone integration — reception under pressure: mounted beneath the lower outlets of a cyclone, bag filter or silo, the airlock receives the dense rawmaterial mass from the upper hopper through a sealed cast inlet. Precise-tolerance rotor pockets — isolated circular conveying: the inner rotor turned by the drive motor fills the geometric pockets with product and carries it down in a circular motion; the tight tolerances between the heavy-duty cast body and the precisely machined rotor vanes limit air blowby in the reverse direction. Air-isolated flow discharge — loss-free mechanical discharge: the product in the rotor pockets is shed by gravity at the lower point onto the next conveyor or pipeline, while the airlock continues to hold the pressure difference (vacuum or pressure regime) between the top and bottom of the line.

KEY ADVANTAGES

• High-density GG25 grey-cast-iron design. The body and rotor are made of high-castingquality grey cast iron (GG25) with a homogeneous internal structure; the high graphite structure inherent in cast iron acts as a natural lubricant during raw-material flow and reduces friction.

• Minimum air leakage via precise CNC machining. Machined in a single operation on highprecision horizontal CNC centres, the body interior and rotor vanes offer flawless axial concentricity; by means of this precision, air leaks are kept to a minimum and line pressure is preserved.

• Economical operation and easy maintenance cost. The standard grey-cast-iron design maximises spare-part availability and serviceability; industry-standard spare-part and component compatibility keeps operating maintenance costs at the most economical level.

• Wide model and capacity variations. It is made in various volume and capacity options to suit the mounting-position design, the pipelines’ pressure/vacuum values and the hourly target output of the product processed.

ENGINEERING NOTE

The standard grey-cast-iron airlock is the most rational, proven sealing solution in industrial flour and feed plants. The high wear resistance and machinability of GG25 grey cast iron ensure the critical rotor-body radial clearance is preserved throughout operation. Combined with correctly selected speed and motor power, it prevents the static-pressure fluctuations that could clog pneumatic pipes and guarantees a stable line flow plant-wide.