Tub Grinder Output Size and First-Pass Throughput Checks for C&D Wood

Tub grinder output size and throughput for C&D wood should be judged by first-pass accepted output, not by everything leaving the conveyor. A controlled test keeps the incoming wood fraction traceable, records oversize and contamination separately, and relates screen choice to the destination’s actual acceptance method.

Release a recoverable wood fraction

Define which clean offcuts, pallets, crates or other approved wood may enter. Unsorted demolition debris, unknown treated wood, loose metal, concrete, masonry, cable, wire and soil-rich sweepings need separate handling. Grinding cannot convert an uncontrolled mixture into verified biomass.

Use the construction and demolition application page as process context, then write project-specific receiving, quarantine and destination rules.

Define output acceptance before choosing a screen

State the intended outlet, sampling frequency, sample mass or volume, oversize rule, fines observation, visible contamination check and who may release the pile. The same output may be acceptable for one downstream process and unsuitable for another. Keep every assumption dated and attributable.

Do not equate screen opening with assured particle size. Feed geometry, screen condition, wear, recirculation, moisture and sampling all affect observed output. Use the exact machine documentation to confirm approved screen options.

Measure the first-pass mass balance

Stream	Record	Why separate it
Released input	Scale and lot identity	Defines tested feed
Accepted first-pass output	Passed sample and mass	Supports useful throughput
Oversize	Mass and disposition	Shows recirculation burden
Rejected contamination	Type, mass and source	Tests receiving control
Unprocessed remainder	Mass at test end	Closes the balance

First-pass recovery (%) = accepted first-pass output / released input × 100

First-pass throughput = accepted first-pass output / total elapsed hours

Report measurement error and unexplained difference. Do not force a mass balance to equal 100 percent by assigning missing material to accepted output.

Use a representative timed trial

Run identified lots with the same loader, preparation, screen, timing definitions and sampling method. Record productive grinding time and total elapsed time, including sorting, loader gaps, stops, cleaning, recirculation and output handling. Repeat enough stable runs to show variation rather than publishing one peak interval.

Compare the planned work cell with the tub grinder product range. A product page supports configuration discussion but cannot validate an uncontrolled project stream.

Sample output across time and position

One convenient sample may miss coarse surges or fines. Collect according to a written method at several intervals, combine or report them as defined, and preserve the lot, run and time. Photograph output with a scale reference and record moisture method when it affects the destination.

Keep output piles separated until their samples are released. If runs with different screens or material classes are mixed, the project loses the evidence needed to choose a configuration.

Investigate variation before raising feed rate

If accepted throughput falls, compare loader gaps, feed geometry, moisture condition, screen loading, oversize, discharge restriction and stops. Change one controlled variable at a time. Feeding faster into an unstable work cell can increase recirculation, bridging or unplanned stops without increasing acceptable output.

For an engineering variable-isolation method, review the feed-size, moisture and screen test structure and create a distinct C&D wood lot record.

Apply clear stop rules

Stop for suspected loose metal or stone, smoke, abnormal heat, unusual noise or vibration, damaged guarding, blocked discharge or lost communication. Use the exact isolation, inspection and restart procedure for the selected machine. Record the event against the incoming lot and sequence.

Output-and-throughput release checklist

• Incoming material boundary and destination are written.
• Screen identity and condition are recorded.
• Output sampling and acceptance are agreed before the run.
• Accepted output, oversize, rejects and remainder are weighed separately.
• Productive and total elapsed time are both reported.
• At least several representative runs show variation.
• Every exception has an owner and disposition.

Prepare evidence for configuration review

Send lot photographs, geometry, moisture method, contamination exposure, target output, sample results, screen record, loader and timed-run data through the TubGrinderCN contact page. For buyer-side capacity planning, the WeiDong site-test guide provides a compatible gross-time framework. Final selection must follow the actual material, destination and site.

Calculate useful yield together with throughput

A project can raise conveyor rate while lowering first-pass recovery. Report both accepted tons per elapsed hour and accepted output as a share of released input. Add recirculation time and rejected material to the record. This prevents a coarse setting from appearing commercially superior when the destination requires extra processing.

Compare scenarios with the same destination rule. If the outlet changes, start a new comparison. Record the output pile identity so accepted and pending material are not mixed before release.

Preserve evidence for regional support

Keep photographs, lot records, sample results, screen identity, event logs and maintenance observations in a shared project pack. When remote support is needed, send the time sequence and verified machine information rather than a conclusion such as “low capacity.” This helps separate feed, configuration, output and work-cell causes.

List training language, service contacts, initial spares, technician travel basis and the responsibilities for site preparation, unloading and commissioning. Use dated quotations for cost or lead-time inputs; where evidence is missing, assign an owner instead of inventing a value.

Review the decision with all process owners

Receiving confirms the released feed class, operations confirms loader and timing records, maintenance confirms configuration and event observations, and the destination owner confirms output sampling. Record disagreements and missing evidence rather than averaging unlike assumptions into one throughput number.

Close the review only when each stream has a documented disposition and the output record can be traced to its incoming lot.