If you aren’t performing maintenance regularly on your equipment, this story is a good reason to start.
During a recent AZO tech call, the facilities manager let us know they hadn’t kept up with maintenance for their four screeners, and several bearings were worn out. We got to work on rebuilding two screeners at the facility, but weren’t able to work on the others due to a lack of production downtime.
Unfortunately, those worn-out bearings had already set off a cascade effect, and the subsequent vibrations caused the screeners on their other lines to fail. Skipping a regular maintenance schedule cost this plant somewhere between $15,000 and $20,000 per replacement, plus the production they lost along the way.
The takeaway: Preventive maintenance would have caught the first bad bearing early. Instead, those worn parts turned into a full teardown.
We’ve talked about the importance of safety in maintenance before, and now we’re getting specific. Here’s what to check on each component in an AZO system — and how often — so a small problem stays small.
The checks below come from the operator's manual for each component. They're a starting point for building a maintenance routine around your specific equipment. Always follow the manual for your exact model because intervals and limits may vary.
Screeners pull out agglomerates, foreign material, and oversized particles before they reach production. Given the failure story we’ve shared, they should earn close attention.
Inspect for holes, cracks, wear, incorrect mounting, and product buildup. Clean as needed and replace a damaged screen right away. Inspect the screen cylinder daily.
Check rotating parts for wear, damage, unusual noise, vibration, or looseness. This is where the four-screener failure started. Inspect the shaft seals and bearings, and use only the specified food-grade lubricant when lubrication is called for.
Test the safety switches and guards, verify earthing (especially after removing a conductive component), and check the product inlet and outlet connections and gaskets for dust leakage.
Safety note: Empty and depressurize the screener, isolate and lock out electrical and pneumatic supplies, and confirm the machine can't restart before you begin.
Screw feeders handle dosing, from coarse bulk additions down to fine micro-ingredients. AZO builds several models to choose from. Here’s what to check.
Clear product buildup and inspect the screw flights, housing, inlet, outlet, and quick-release clamps for rubbing, wear, cracks, deformation, or contamination. AZO designs in quick-release clamps and removable screw assemblies specifically to make this easier.
Inspect the geared motor, mounting fasteners, vibration hardware, and screw connection for looseness, abnormal noise, excess heat, or vibration. Confirm the screw runs smoothly at both coarse- and fine-dosing speeds. Follow the drive manufacturer's manual for gearbox lubrication; don't assume a lubricant or an interval.
Inspect the outlet shutoff valve, air tubing, fittings, and actuator for leaks or incomplete closing. Confirm the valve stops product from trickling after the dosing cycle. On gravimetric AZODOS models, also verify stable weighing and dosing.
Safety note: Apply lockout/tagout, stop and isolate product flow, relieve compressed-air pressure, and verify zero mechanical energy before opening clamps or reaching the screw. Treat the screw, agitator, drive, and shutoff valve as pinch-point and stored-energy hazards.
Filters separate product from the conveying air and keep dust contained. AZO's AF filters are built so the upper section moves aside for filter-hose inspection.
Check filter hoses, cartridges, or bags for product buildup, blockage, tears, or heavy wear. Clean or replace damaged elements to keep airflow and product separation where they should be.
Verify the pulse-cleaning valves, nozzle bars, pressure regulator, and compressed-air supply are working. Watch differential pressure closely. A rising pressure difference usually means clogged elements or pulse cleaning that isn't doing its job.
Drain moisture from the compressed-air chamber. Check seals, clamps, connections, and the housing for air leaks, damage, or loose parts.
Safety note: Isolate the conveying system, shut off the compressed-air supply, and depressurize the equipment before opening the filter.
The blower is what moves material through the whole pneumatic conveying system. Three things to stay on top of:
Inspect oil level and condition in gearboxes, bearings, and oil-lubricated pump sections. Change the oil and oil filter on the recommended schedule. Check the housing, seals, drain plugs, and connections for any sign of leakage.
Inspect inlet filters and screens for dust and product buildup. Replace exhaust or oil-mist filters on applicable vacuum pumps. Clean cooling fins, ventilation openings, and heat exchangers so the unit doesn't overheat or lose capacity.
Listen and feel for abnormal noise, vibration, temperature, pressure, or vacuum. Check the drive, coupling, and mounting hardware for smooth operation. On blowers, inspect the safety valve, unloading device, and check valve.
Safety note: Shut down and lock out the unit, vent connected piping to atmospheric pressure, and let hot surfaces cool before you start. Exact service intervals depend on the model and how hard the unit runs.
Rotary valves meter product into the conveying line, which means constant contact with the material and steady wear. Rotary valve manufacturers typically recommend these checks every three months or 2,500 operating hours, whichever comes first.
Confirm the valve turns smoothly, with no scraping, binding, unusual noise, or excess vibration.
Look for product or air leaking past the seals. Verify the purge-air system is working and readjust it if needed.
Inspect the chain and sprockets for wear and alignment. Correct the tension and lubricate the chain.
Safety note: Before removing guards or touching the valve, stop the equipment, apply lockout/tagout, isolate purge-air pressure, and verify zero energy. Never service a valve while it's running.
Dehumidifiers keep moisture out of hygroscopic products and out of the conveying air.
Inspect the process-air and reactivation-air filters for dust and blockage. A restricted filter cuts airflow and dehumidification efficiency, and it can trigger overheating alarms.
Confirm the desiccant wheel turns whenever the unit runs. Check the rotor for dirt, blockage, moisture damage, or physical damage. Inspect the rotor seals, drive belt or chain, motor, and support rollers for wear or misalignment.
Verify process and reactivation airflow against the unit's specified values. Check the reactivation outlet temperature, and inspect the heater or burner, blowers, motors, electrical connections, and alarms for anything abnormal.
Safety note: Shut down the unit, let the heater and internal parts cool, and isolate and lock out all electrical, gas, steam, or other energy before starting. Intervals and temperature limits vary by model, so follow the manual for your specific unit.
A diverter valve routes product between a straight and an angled piping path when the system needs to send material somewhere else. AZO installs dual-pipe diverters most frequently with alternative styles when the application warrants.
Check the internal seals and the plug or rotor for wear, air leakage, or material buildup. Worn seals cost you conveying efficiency and can cause cross-contamination between product streams.
Cycle the valve to confirm it switches smoothly and completely between positions. Inspect the pneumatic or electric actuators, limit switches, and position indicators.
Make sure product isn't accumulating inside the housing or on the sealing surfaces. Buildup leads to jamming, poor sealing, and faster wear.
Safety note: Isolate the air supply and depressurize the system before maintenance. These checks matter even more with abrasive or sticky materials.
AZO hose switches direct material between conveying lines and seal off the line that isn't in use. They go in with nearly every blower. Three types show up most often:
All three use a sliding hose connection for a smooth product path with minimal directional change, which helps hold down pressure loss and buildup. Here’s the maintenance across all hose switches:
Clear buildup from the slide plate, hose connectors, mating surfaces, and internal passage. Check the conveying hoses and connections for abrasion, cracking, blockage, or looseness. On SLD units, the slide assembly comes out for cleaning.
Check the sealing surfaces, and the inflatable seals on SLD models, for wear, damage, or air leakage. Inspect the pneumatic tubing, fittings, regulators, and pressure switch. AZO calls for clean compressed air and a system supply pressure of 4 to 8 bar on the listed models.
Cycle the pneumatic cylinder and confirm the slide moves freely and sits flush with each connection. Check the adjustable stops, mounting hardware, and position or pressure feedback so the selected line seals completely.
Safety note: Isolate and depressurize the conveying and compressed-air systems before maintenance. Empty the conveying pipe before changing position; AZO requires this specifically for SLS units.
Butterfly valves shut off and control flow at transfer points. AZO most commonly installs seated wafer type butterfly valves. In sanitary applications, soft-seated clamp type butterfly valves are used.
Check the seat liner, disc, and shaft seal for wear, damage, or leakage. Replace worn seals if you find leakage.
Run the valve through its full open and close travel to confirm smooth movement. Verify the actuator, gearbox, or handle works and that the valve reaches fully open and fully closed.
Check flange bolts for tightness, look for external leaks or corrosion, and clear any debris that could score the sealing surfaces.
Safety note: Isolate and depressurize the pipeline before any maintenance.
Every component we’ve outlined feeds the next: a worn rotary valve drags down conveying efficiency and a clogged filter makes the blower work harder. And as the four screeners story showed, one neglected bearing can spread damage throughout the entire line.
We recommend planning maintenance across the system, not component by component in isolation. Some quick tips on that process:
If you'd rather have AZO's team handle it, that's what aftermarket services are for. We provide scheduled maintenance, rebuilds, spare parts, and on-site support from the people who engineered the system. Explore AZO Aftermarket Services to keep your equipment running the way it was designed to.