Switching a dense-phase conveying line between destinations is harder than it looks. The material moves slowly and at high pressure, the line carries abrasive product, and any leakage at the diverter bleeds conveying air and degrades the whole system. The valve has to seal properly under pressure and tolerate abrasion without frequent attention.

In dense-phase conveying, material moves as a plug or a slowly moving bed rather than as a dilute suspension. Pressures are higher, velocities are lower, and the material is in intimate contact with every component in its path. Two consequences follow for the diverter: it must seal against real pressure, and it must resist abrasion from a continuously renewed supply of particles.

The flap diverter is the classic dense-phase solution, and the reason is elegant: it uses the conveying pressure itself to hold the flap against the outlet that is not in use. There is no separate sealing force to engineer and no actuator torque to fight the line pressure. The harder the system pushes, the more firmly the flap seats.

See the VAB flap diverter valve and the VAB application article. The VAB body is aluminium.

If the product is sharp-edged or highly abrasive, a flap or plate design presents a thin edge to the stream and that edge will wear. A plug diverter rotates a substantial plug into position instead, presenting a smooth, self-supporting face that spreads the wear and resists erosion far better.

See the KFZ plug diverter valve for low-wear abrasive duty. The KFZ body is stainless steel.

Where the line must be cleaned, pigged or emptied completely between products, the diverter needs a full-bore passage with no recessed cavity to trap material. A ball diverter with a ported ball gives exactly that, and its self-cleaning geometry suits product changeovers and food or pharmaceutical duty.

See the KFQ ball diverter valve — a full-bore, self-cleaning design in stainless steel.

A diverter in a gravity chute has a much easier job than one in a pressure conveying line. In gravity duty the material simply falls and the valve only has to divert it, which is where a compact plate design makes sense — see the KFB plate diverter valve. Do not put a gravity-rated design into a pressurised line and expect it to seal.

With those six answers we can specify a type and a material in one reply. See the diverter valve range, the pneumatic conveying valves overview, or the full product list.