A diverter valve does one job: take a single stream and send it down one of two or more routes. Most of the time the specification is written quickly, and most of the problems in service trace back to that. Plate, plug, ball and flap designs seal differently, wear differently and suit different products. Here is how they compare.

Three requirements, and they conflict. It must seal the inactive port so product does not cross-contaminate or leak. It must not obstruct the active path, or capacity drops and wear accelerates. And it must survive thousands of cycles in a stream that may be abrasive, hot or sticky.

The KFB plate diverter is the default for dry powder and granules at moderate pressure. A flat plate swings or slides to cover one port. It is compact and cheap to actuate, which makes it the usual choice for gravity and light pneumatic duty.

The weakness is that the sealing face is in the stream. With abrasive product the plate edge erodes, and once the face is no longer flat the seal degrades. Where the product is mildly abrasive but the budget is tight, it is still often the right answer — just plan the plate as a wear part.

The KFZ plug diverter drives a tapered plug into the port to seal it. The sealing surface is not swept by the stream in the same way, so it survives abrasive product better than a plate, and it seals more firmly under differential pressure. The trade-off is actuation torque and physical size.

The KFQ ball diverter rotates a machined ball with a bore through it. When the bore aligns with a port, product passes cleanly; rotating the ball moves the solid surface across the port. Sealing is very good and leakage is minimal, which is why ball diverters are used where cross-contamination genuinely matters — food, pharmaceutical and multi-product lines.

The cost is weight, size and price, plus a cavity around the ball where product can accumulate. In sticky or caking materials that cavity needs attention.

The VAB flap diverter is built with an aluminium body. That makes it the lightest option, which is exactly what pneumatic conveying lines and mobile equipment need. It suits light dry powder, granules and air-conveyed product. It is not the design for high pressure, heavy abrasion or aggressive chemistry — for those, move to stainless and to a plug or ball design.

See also the flap diverter valve application guide and the flap diverter range.

Sealing design is one decision; material is another. In our range the KFB, KFZ and KFQ are supplied in stainless steel, which covers food, pharmaceutical and mildly aggressive duty. The VAB is aluminium, chosen for weight. If the application is hygienic, stainless is not optional — every wetted part must be 304.

Tell us the product, the pressure and the routing and we will specify the design. Browse the diverter valve range or read the pneumatic conveying valve guide.