Tea Processing Factory

Tea processing factory — process automation

A tea factory in the Kenyan highlands ran its withering, CTC and drying lines on ageing relay-logic starters. Operators had no visibility of line state, quality depended on manual timing, and a single starter fault could stop the whole line for hours.

The challenge

Withering fans, conveyors and dryers each had their own vintage of starter, with no interlocking between stages and no records for the factory’s quality audits. Power interruptions forced full manual restarts, and reject rates climbed whenever experienced operators were off shift.

What NPE built

• ✓A new motor control centre with segregated starter sections for withering, CTC, fermentation and drying lines
• ✓VFD control on withering fans and dryer feeds so airflow and feed rate follow the recipe, not the operator’s judgement
• ✓PLC sequencing with stage interlocks and automatic staged restart after a supply interruption
• ✓An operator HMI showing line state, alarms and batch timers at a glance
• ✓Batch logging wired into the factory’s quality system for full traceability

The results

With recipe-driven control replacing manual timing, reject rates fell by nearly two-thirds and throughput rose without any new process machinery. Every batch is now logged end to end, and staged auto-restart means a mains dip no longer costs a shift. NPE continues to support the factory under a planned maintenance schedule.