ʻO ka pahu pulper kahi mea hana kiʻekiʻe o ka ʻōpala ʻōpala pepa, ka mea nui i haku ʻia me ka hopper hānai, ka pahu pahu, ka pahu pale, ka mīkini hoʻoili, ke kumu a me ka paepae, ka paipu wai wai a pēlā aku. ʻO ka pahu pahu pahu he wahi pulupulu a me kahi wahi nānā, hiki ke hoʻopau i nā hanaʻelua o ka pulping a me ka nānāʻana i ka manawa hoʻokahi. Hoʻouna ʻia ka pepa ʻōpala i kahi ʻāpana pulping kiʻekiʻe e ka conveyor, ma ka neʻe ʻana o 14% ~ 22%, lawe pinepine ʻia a hāʻule i kahi kiʻekiʻe e ka scraper ma ka paia o loko me ka hoʻololi ʻana o ka pahu, a kuʻi me ka ʻili paʻa o loko o ka pahu. Ma muli o ka ʻoluʻolu a me ka ikaika ʻoi aku ka maikaʻi a me ka hoʻonui ʻana i ka friction ma waena o nā fibers, ua hoʻokaʻawale ʻia ka pepa ʻōpala i nā fibers.