An HZS120 concrete plant can operate reliably for 15 years or more with proper maintenance — daily visual checks, weekly lubrication, monthly inspections, and timely replacement of wear parts such as mixer liners and screw conveyor sections. Neglecting any one of these shortens the plant's working life significantly.
A five-minute walk-around before the first batch of the day catches most developing problems early. Start at the mixer: listen for unusual noise from the gearbox, check the oil level sight glass, and inspect the main shaft seals for leakage. Move to the weighing hoppers — make sure the load cells are clean and free of concrete buildup that could affect accuracy. Check the belt conveyor for mis-tracking, worn edges, or material spillage around the tail pulley. Look at the air compressor's moisture drain valve (open it briefly to release any water). Finally, test all emergency stop buttons and the mixer door interlock. Document anything unusual in the plant logbook. This routine takes no more than five minutes and it is the single most effective way to prevent unexpected breakdowns.
Lubrication is the cheapest form of maintenance and the most commonly skipped. The HZS120's twin-shaft mixer uses an automatic grease lubrication system that injects grease into the main shaft bearings every 30-60 minutes of operation. Check the grease reservoir level daily and refill with the manufacturer-recommended lithium-based grease (NLGI Grade 2). Manual grease points — such as the discharge door hinges, screw conveyor hanger bearings, and belt conveyor idler rollers — should be greased every 40 operating hours with a hand grease gun. Never mix different grease types in the same bearing, as incompatible bases can liquefy and flow out, leaving the bearing dry.
The mixer liners (wear-resistant steel plates that line the mixer drum) and mixing arms are the HZS120's most frequently replaced wear parts. Under typical production of 8-10 hours per day, mixer liners last 8-12 months and mixing arms last 6-9 months. Replace them when the liner thickness is worn to less than 10 mm (check with a thickness gauge monthly) or when the gap between the mixing arm tip and the liner exceeds 12 mm. Running with excessively worn liners or arms reduces mixing quality, increases cycle time, and can damage the mixer drum body — a much more expensive repair.
The belt conveyor that feeds aggregates from the ground hopper to the upper bins is a common failure point. Inspect the belt daily for cuts, frayed edges, or delamination. Check belt tension by ensuring there is no visible sag between idler rollers while the belt is loaded. The conveyor's drive pulley lagging should be examined monthly — worn lagging reduces friction and causes belt slip. For plants with a bucket elevator, inspect the buckets for wear and the chain for elongation every 200 operating hours. A stretched chain that jumps a tooth on the sprocket can cause a catastrophic jam that requires a full strip-down to repair.
The control panel is the plant's nervous system. Keep cabinet doors closed and sealed to prevent dust ingress — fine cement dust is conductive and can short-circuit PLC boards. Open the cabinet monthly and inspect all terminal blocks for tightness; vibration from the plant can loosen connections over time. Use a compressed-air blower (not a wet cloth) to clean dust from VFD heatsinks and relay contacts. Check that the emergency stop circuit functions correctly by testing each E-stop button in turn. Back up the PLC program at least once per quarter — a corrupt PLC without a backup means weeks of downtime while a new program is written.
The HZS120 is built for demanding conditions, but climate still matters. In hot climates (above 35°C ambient), change the hydraulic oil and gearbox oil to a higher viscosity grade to prevent thinning and leakage. Inspect the air-conditioning unit in the control cabin if fitted — overheating PLC racks cause intermittent faults that are hard to diagnose. In cold climates, use winter-grade lubricants and ensure the air compressor's auto-drain valve operates correctly. Silo filter cartridges should be inspected monthly in dusty environments and replaced when the pressure differential across the filter exceeds the manufacturer's limit. A simple adjustment of maintenance intervals based on local conditions can add years to the plant's life.
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