The most common techniques for detaching clogged powders, in addition to compressed air, are mechanical methods such as vibrating and impacting/hammering.

Where the bulk material flow is disrupted or irregular, putting the silo outlet (hopper) into vibration often is the only applicable solution. This has to be done carefully in order to avoid damage to the silo hopper and can be achieved by using pneumatic knocker,
The pneumatic knocker is used for bulk goods with material flow problems such as bridge, siphon and residue formations, when high speed shakers and vibrators with soft sine-shaped oscillations are no longer effective. The effect of the knocker is comparable to that of the famous “silo hammer”, but without distorted silo spouts additionally impeding the material flow.
position by means of a spring.
https://news.bulk-online.com/bulk-solids-handling-archive/so...

The present device relates to an air knocker that strikes wall surfaces of a powder storage tank such as a silo, hopper, etc. to prevent the function of the powder storage tank from being degraded.
Le dispositif de l'invention concerne un marteau pneumatique qui frappe des surfaces de paroi d'un réservoir de stockage de matière pulvérulente tel qu'un silo, une trémie, etc. afin de prévenir une dégradation de la fonction dudit réservoir.
production - wipo.int
https://fr.techdico.com/traduction/anglais-francais/air knoc...

By applying pneumatic vibrators in the problem area, it will provide the best solution. Pneumatic vibrators will shake off the clogged or attached material and eliminate friction during automatic production.
https://www.sentronic.com/data/product_datasheets/FINETEK__A...

The difference between choosing a continuously operated vibrator and an intermittently pulsed hammer or impactor lies in the nature of the application and material.
For those applications where you want to clear every last bit of sticky or clinging material from a container such as a weigh batch hopper, cyclone, or a spray dryer, a pneumatic or electromagnetic impact device is often your best choice.
https://www.decavibrator.com/product-type/pneumatic-electric...

PS model pneumatic hammers are part of the product range assisting with silo and hopper flow. They are used to destroying arches. The energy released at periodic intervals upon impact is transmitted directly to the wall. Hammers cause a highly violent impact on the wall. They are suitable for all types of silos and hoppers.
https://www.palamaticprocess.com/bulk-handling-equipment/pne...

"vibrator" "hopper" About 20.100.000 results (0,51 seconds)
"pneumatic vibrator" "hopper" About 14.900 results (0,43 seconds)

"hammer" "hopper" About 15.200.000 results (0,54 seconds)
"pneumatic hammer" "hopper" About 410.000 results (0,61 seconds)
"silo hammer" "hopper" About 2.390 results (0,45 seconds)

"knocker" "hopper" About 1.130.000 results (0,69 seconds)
"air knocker" "hopper" About 4.230 results (0,39 seconds)
"pneumatic impactor" "hopper" About 1.400 results (0,52 seconds)

"impactor" "hopper" About 237.000 results (0,45 seconds)
"pneumatic knocker" "hopper" About 1.340 results (0,38 seconds)