Description
Hangzhou Ever-Power Sprocket Co., Ltd.
A paper mill’s bleach plant runs on an annual shutdown cycle. Every component in the chlorine-dioxide and hypochlorite environment must last 12 months between planned stops — or force an unplanned intervention that shuts down the whole pulp line.
The Annual Shutdown Interval: What It Demands from a Drive Component
Large continuous-process plants — paper mills, chemical manufacturers, fertiliser facilities — operate on annual or biannual planned shutdown (turnaround) schedules. Every day of unplanned downtime between scheduled turnarounds is a production loss that has no recovery path in the annual plan. The maintenance engineering team’s job, in the interval between turnarounds, is zero unplanned stops. This means specifying drive components whose realistic service life exceeds the turnaround interval, not just meets it on paper. A carbon steel #80 sprocket in the bleach plant of a paper mill — exposed to chlorine dioxide (ClO₂) or hypochlorite (NaOCl) solution mist at elevated temperatures — will not last 12 months. In most cases it corrodes to the point of compromised function within 90 days. The Ever-Power #80 Stainless Steel Sprocket in 316 SS is the correct specification for this interval: its passive oxide layer regenerates after each chemical exposure, its chloride resistance prevents the pitting that afflicts 304 SS in bleach-plant atmospheres, and its machining precision ensures that after 12 months of operation in a corrosive atmosphere, the tooth profile is still within the ANSI replacement limit — because the only failure mechanism that has been active is mechanical wear, not corrosion.
Turnaround Planning: What the Maintenance Team Needs at Year-End Inspection
During an annual turnaround, the drive inspection checklist for a bleach-plant conveyor includes tooth profile wear, bore fit condition, hub integrity, and pitch circle accuracy — all measured against the as-new dimensional record. The maintenance decision — replace or continue service — requires that the as-new data exists to compare against. Our standard documentation package, which includes the CMM dimensional record for pitch diameter, bore, and tooth form, provides exactly this baseline. At turnaround time, your metrology team re-measures against our CMM record and the decision is objective, not a judgement call. Sprockets that are within tolerance go back in. Those at or approaching the replacement limit are replaced with the next pre-ordered set.
Technical Specifications
| Parameter | Value |
|---|---|
| Chain No. | ANSI 80 |
| Pitch | 25.4 mm (1″) |
| Recommended Grade | 316 SS (bleach plant, ClO₂, NaOCl environments) |
| Tooth Range | 8T – 60T (larger on request) |
| Pitch Accuracy | ±0.025 mm tooth-to-tooth, class A |
| Documentation | MTR + CMM dimensional report, standard |
Chemical Resistance in Bleach Plant Atmospheres
The bleach plant is the most aggressive chemical environment in a paper mill. Chlorine dioxide (ClO₂) used in elemental chlorine-free (ECF) bleaching is a powerful oxidising agent at elevated temperatures; sodium hypochlorite (NaOCl) in the chlorine stage provides additional chloride exposure; and the peroxide (H₂O₂) stage in ECF/TCF sequences adds an oxidising/bleaching chemistry layer. 316 SS resists all of these reliably at the concentrations and temperatures used in standard bleach-plant operation. The key is that passivation treatment is applied before installation — citric acid passivation removes any free-iron from machining tooling and maximises the oxide layer before the sprocket is exposed to the chemical environment. We include passivation at no additional charge for all chemical plant and bleach plant orders.
Drive System Components for Chemical Plant Environments
Build a complete turnaround-interval chemical plant drive from one supplier with consistent grade documentation throughout. Our large stainless steel sprocket systems include:
- ANSI 80 316 SS Roller Chain — passivated on request, with MTR
- 80H Heavy Series SS Chain — for drives at peak capacity in the chemical environment
- Passivated Turnaround Kits — pre-kitted driver/driven sprocket pair + chain, ready for shutdown installation
- QD Taper Bushing Sets — for rapid replacement during the turnaround window
- Dimensional Baseline Package — CMM report for new installation, for comparison at next turnaround inspection
What Chemical and Paper Mill Engineers Report
“Bleach plant conveyor — 316 SS #80 sprockets through a full 12-month interval between turnarounds. At the shutdown inspection, tooth wear was within tolerance and the dimensional report matched our as-installed baseline. Went straight back in for another year.”
“We pre-order turnaround kits from Ever-Power 3 months before shutdown. They arrive on schedule, documentation is complete, and the team can do the changeout during the turnaround window without hunting for parts or approvals.”
“Replaced Rexnord carbon #80 sprockets with Ever-Power 316 SS in our chlorine stage. Carbon units lasted 6–8 weeks. We’re now at 11 months on the first set of SS units and they passed inspection. Remarkable difference.”
Pre-Order Your Turnaround Kits 3 Months Ahead
+86-571-88220653 | [email protected] | SHENHUA ROAD, HANGZHOU, CHINA
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