D21H 23/00

Processes or apparatus for adding material to the pulp or to the

Official title: Processes or apparatus for adding material to the pulp or to the paper (applying liquids or other fluent material to surfaces, in general B05; processes for making continuous lengths of paper D21F11/00)

D21H23/00 (Processes or apparatus for adding material to the pulp or to the) appears on 1,856 US grants and 1,505 published applications in this corpus.

Search patents in D21H

Granted patents: 1,856
Published applications: 1,505
Assignees: 811
Inventors: 3,724
Latest grant: 6 Oct 2026

Filings by year

D21H 23/00: granted patents and published applications per publication year
Year	Granted patents	Published applications
1976	24	0
1977	16	0
1978	13	0
1979	3	0
1980	12	0
1981	18	0
1982	23	0
1983	23	0
1984	12	0
1985	25	0
1986	13	0
1987	16	0
1988	36	0
1989	40	0
1990	40	0
1991	29	0
1992	37	0
1993	30	0
1994	29	0
1995	28	0
1996	40	0
1997	53	0
1998	68	0
1999	71	0
2000	74	0
2001	59	12
2002	63	47
2003	60	81
2004	55	106
2005	29	88
2006	30	65
2007	46	60
2008	31	68
2009	21	53
2010	36	51
2011	46	47
2012	32	38
2013	47	62
2014	37	59
2015	36	50
2016	35	66
2017	52	51
2018	43	51
2019	38	54
2020	43	79
2021	40	57
2022	60	54
2023	40	60
2024	29	80
2025	46	38
2026	29	28

By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.

Processes or apparatus for adding material to the pulp or to the

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