Rhewum

RHEWUM GmbH is a German manufacturer of high‑precision screening equipment and particle separation technologies, headquartered in Remscheid. Established in 1927 as Rheinische Werkzeug- und Maschinenfabrik, the company has grown into a global supplier of screening and sorting solutions for industries including solid chemicals, fertilizers, minerals, food processing, and recycling.^[1]

The company has developed direct‑excitation and double‑frequency screening technologies, which achieve separations even with challenging materials such as sticky, hygroscopic, or fine powders.^[2] Rhewum machines are used in fertilizer production, including calcium ammonium nitrate and phosphate granules^[3] in mineral industries such as potash and silica sand,^[4] and in food processing sectors including sugar and salt.^[5] The company also provides large‑scale systems for industrial projects, such as biomass screening for renewable energy.^[6]

Its equipment is employed by producers including Yara^[2] and Dubai Aluminium (DUBAL).^[7]

Alexander Gassinger & Co. AG was a tool and machinery manufacturer based in Remscheid, Germany, active in the early 20th century. Known for precision engineering, the company was part of the German mechanical industry before and during the interwar period.^[8] In 1927, it was reorganized as Rheinische Werkzeug- und Maschinenfabrik, creating the foundation for what would later become Rhewum GmbH.^[9] After World War II, the company used its facilities to produce turbines and cookers, and lantern production became a major activity until the mid‑1960s. Efforts to compete with established lantern manufacturer Feuerhand proved unsuccessful, and lantern production ended around 1964.^[8]

By the 1960s, Rhewum had entered the screening technology sector. In 1967, it delivered its 1,000th screening machine.^[10]

Two innovations defined this period, RHEmoto (known as WAU until 2021), screens that applied high‑frequency vibrations directly to the mesh; ^[11] and RHEsono (known as WA until 2021), driven by external electromagnetic systems, these machines were especially effective at processing sticky or difficult materials like sugar, salt, and agrochemicals.^[10][12]

In July 1967, longtime managing director Karl Favorke stepped down, succeeded by Albert Kellerhoff.^[13] In 1968, physicist Rudolf Krause joined management,^[14] and in the mid‑1980s, engineer Wolfram Blachetta assumed leadership, further professionalizing the company’s technical direction.^[15]

In the 2000s, Rhewum advanced digitalization efforts by introducing optical measurement systems including RHEsize (2005), FlowChecker (2013), and the ScreenSpector app (2014, later renamed ScreenCheck). The opening of a Technology Center in 2014 allowed for on‑site testing and customized machine solutions.^[16]

Following Wolfram Blachetta’s tenure, Sigurd Schütz, who had worked as Sales Director since 2004, was appointed Managing Director on April 1, 2007.^[17][18]

The company also pursued international expansion, opening subsidiaries in India and the United States to provide local customer support and expand its global presence.^[19]

RHEWUM specializes in designing and manufacturing advanced screening machines and conveyors for industrial use. Its products include high‑frequency vibratory screeners, double‑frequency machines, linear vibrating screens, and wet/dewatering classifiers.^[20][21]

High‑frequency and direct‑excitation screens apply vibration directly to the mesh while the housing remains static, achieving accelerations up to ~15 g.^{[22][23][24][25]}

Double‑frequency (DF) screening machines are designed for medium to coarse separations (about 1–25 mm), and use two unbalanced motors running at different speeds. One motor loosens material with large amplitudes, while the other applies high‑frequency vibration to refine separation.^[21][26]

For simpler classification and protective screening, RHEWUM produces low‑maintenance linear vibrating screens.^[20] Its wet and dewatering systems are designed to remove water from slurry feeds, achieving low residual moisture and effective separation even under cohesive conditions.^[20] The company also supplies dust‑tight conveying systems for energy‑efficient bulk transport and dosing.^[20]

In 1967, the company was granted a patent for "Screen with vibration‑isolated vibration generator" (US3325007A), which introduced a vibration‑isolated generator that improved energy transfer while reducing screen wear.^[27] Additional patents followed, including "Vibrating feeder" (US4221306, 1980), "Beater‑type vibratory screen" (US4469592, 1984), and "Beater‑type power sieve" (US4575420, 1986), all of which enhanced feeding uniformity, vibration stability, and equipment longevity.^[28][29][30]

In the mid‑1980s, the British patent "Screening machine" (GB2139317B) enabled more precise multi‑deck screening.^[31] In 1991, the "Analytical sieve apparatus" (US5059310) introduced automated weighing funnels and cleaning cycles.^[32]

In 2008, Rhewum patented a cross‑flow classifier integrated into a vibratory screen, allowing simultaneous dedusting and ultra‑fine classification.^[33]

GeniusDrive is Rhewum’s in‑house engine brand, producing vibration motors designed for screening and conveying systems.^{[34][35][36][37]}

Founded in 2017 as a Rhewum spin‑off, polymesh is polyurethane screen media, including tensioned mats and modular panels for both wet and dry screening.^[38][39]

Rhewum India was founded in 2017 in Pune and relocated in November 2024 to a technical center and warehouse facility in Bengaluru.^[40] The facility includes test machines for material trials, an on‑site spare parts inventory, and structured service support.^[40]

Established in 2021 and headquartered in Davie, Florida, Rhewum America provides support across North America for dry and wet screening systems, vibrating feeders, and optical sorting technologies.^[41] The subsidiary serves industries such as fertilizers, chemicals, food, mining, and recycling. Services include retrofits, spare parts, wear inspections, and process optimization tailored to U.S. plant schedules, including major summer maintenance campaigns.^[41][42]