Over 10,000+ customers' choice, Focus on screening industry 40+ years
1. Caking – the primary cause of screen blinding. Cocoa powder readily absorbs moisture and forms lumps during storage and transport. Industry standards require cocoa powder moisture content to be below 5%, but if humidity control in actual storage and transport conditions deviates even slightly, hard lumps will form on the powder surface. Once these lumps enter the screening process, they either block the mesh openings and reduce screening efficiency, or are rejected as impurities, causing raw material waste.
2. Shell impurities – the "invisible killer" of purity. After crushing and grinding, small amounts of incompletely ground shell fragments and fibre particles may remain mixed in the powder. These shell particles are coarser than cocoa powder and, if not removed in time, will directly affect the solubility and mouthfeel of the cocoa powder.
3. Electrostatic adhesion – the "screen‑sticking effect" of fine powder. Cocoa powder tends to accumulate static charge during grinding and conveying. Charged fine powder is strongly attracted to the wire surfaces of the screen by electrostatic forces, forming a dense "powder film" that continuously reduces the effective screening area and causes screening efficiency to drop rapidly.
4. Fat adhesion – the "paste‑up" risk of oily materials. Cocoa powder contains approximately 10%‑20% fat. During screening, the fat components tend to adhere to the screen surface, forming a sticky film together with the fine powder, further aggravating screen blinding.
These four challenges overlap – lumps block mesh openings, shell particles contaminate the product, static electricity makes fine powder stick to the screen, and fat accelerates screen pasting – making cocoa powder a recognised "difficult‑to‑screen" material.
The Gaofu S49 series rotary vibrating sieve for cocoa powder uses a vertical vibration motor as the excitation source. Eccentric weights installed at the upper and lower ends of the motor shaft convert the rotational motion into a horizontal, vertical and tilting three‑dimensional compound motion – known as "three‑dimensional vibration". This compound motion is then transmitted to the screen deck, causing the material to move on the screen surface in a spiral outward trajectory.
This three‑dimensional motion has two direct benefits for cocoa powder screening:
First, thorough material dispersion. The three‑dimensional vibration causes the cocoa powder to continuously tumble and disperse on the screen surface. Lumps are naturally broken up during the motion; fibre and shell particles do not concentrate and accumulate; and oily material does not form an adhesive layer locally on the screen surface.
Second, more thorough screening. Every cocoa powder particle, along its spiral outward path, has more opportunities to contact the screen, resulting in a higher passage rate and more complete separation of fine powder from impurities.
The S49 series rotary vibrating sieve supports 1 to 5 screen decks, allowing a single feed to complete multiple steps simultaneously – coarse screening removes large shell particles and lumps, while fine screening obtains the target‑size finished cocoa powder. Screening accuracy can reach up to 600 mesh (0.02 mm) and filtration precision down to 5 microns, fully covering the full range of cocoa powder screening requirements from conventional to ultra‑fine.
1. Efficient Removal of Lumps – Solving Screen Blinding at the Source
Cocoa powder caking is the primary cause of screen blinding. The three‑dimensional vibration trajectory of the Gaofu rotary vibrating sieve for cocoa powder itself has a de‑agglomerating effect – the material continuously tumbles and moves on the screen surface, and slight lumps are naturally broken up before reaching the screen. For harder lumps, the high‑frequency, low‑amplitude vibration effectively shakes them apart, giving individual particles the opportunity to pass through the screen. This not only reduces screen blinding but also prevents lumpy material from being rejected as waste, avoiding raw material loss.
Screening accuracy can reach over 95%, and impurity removal accuracy over 98%. After screening, the cocoa powder has uniform particle size, meeting the strict fineness requirements of chocolate production, baking ingredient processing and other applications.
2. Precise Interception of Shell Impurities – Safeguarding Product Purity
Cocoa powder raw materials may contain incompletely ground shell fragments, fibre particles and other foreign matter. Through precise screen mesh configuration and stable three‑dimensional vibration, the Gaofu rotary vibrating sieve for cocoa powder effectively intercepts all impurities larger than the mesh openings. The standard screen mesh range covers 20 to 300 mesh, with 30 to 60 mesh perfectly matching the particle size requirements for conventional cocoa powder screening.
Intercepted impurities and oversize material automatically move along the screen surface to the reject port and are discharged without manual intervention, enabling continuous operation.
3. Food‑Grade Stainless Steel – Maintaining Food Safety Standards
Cocoa powder is used directly in food processing, so the equipment material that contacts it must meet strict hygiene requirements. All material‑contact parts of the Gaofu rotary vibrating sieve for cocoa powder are made of food‑grade 304 stainless steel. The surfaces are finely polished, with no hygiene dead corners, easy to clean, with no material residue, complying with food safety production standards. For production lines requiring even higher cleanliness, 316L stainless steel is also available.
4. Multiple Anti‑Blinding Mechanisms – Addressing Electrostatic Adhesion and Fat Pasting
To address the electrostatic and high‑fat adhesion characteristics of cocoa powder, the Gaofu rotary vibrating sieve for cocoa powder offers multiple anti‑blinding solutions:
Bouncing ball cleaning system: Food‑grade silicone balls are placed under the screen deck. During screening, the balls continuously bounce against the screen cloth, dislodging adhering oily material and fine powder, keeping the screen clear.
Ultrasonic cleaning system (optional): For severe electrostatic adhesion or ultra‑fine cocoa powder screening, an ultrasonic system can be added. The high‑frequency vibration generated by the ultrasonic transducer is superimposed on the screen surface, so the material on the screen is subjected to high‑frequency ultrasonic vibration in addition to low‑frequency vibration. This effectively solves the problem of mesh blockage caused by agglomeration, static electricity and strong adhesion. Screening accuracy can be improved by over 80%, and throughput increased by 2 to 5 times.
5. Fully Enclosed Sealed Structure – Dust, Moisture and Contamination Protection
During cocoa powder screening, dust escape causes both material loss and workshop contamination. The Gaofu rotary vibrating sieve for cocoa powder has a fully enclosed sealed structure, with screening taking place inside a sealed chamber and no powder escape. The fully enclosed design provides three assurances: first, it prevents dust escape, improving the workshop environment; second, it effectively blocks external moisture, preventing secondary moisture absorption and caking of the cocoa powder during screening; third, it prevents foreign matter from entering the screening system, ensuring the purity of the cocoa powder. The equipment operates with a noise level of below 60dB, making it suitable for clean food processing workshops.
6. Quick Screen Change – Reducing Downtime
Different cocoa powder products require different particle sizes. The Gaofu S49 series rotary vibrating sieve uses a separate mother‑child screen frame structure, allowing screen changes in just 3 to 5 minutes. The mother screen provides structural support, while the fine screen (working screen) is responsible for screening. When the fine screen wears out or a different mesh size is needed, only the fine screen needs to be replaced; the mother screen can be used for a long time. This design reduces consumable screen costs while shortening production line downtime.
About Gaofu
Xinxiang Gaofu Machinery Co., Ltd. was originally founded in the 1980s. After more than 40 years of development, the company has become a "National Specialized and Sophisticated 'Little Giant' Enterprise", a "National Green Factory", a "National High-tech Enterprise", a "National Intellectual Property Advantage Enterprise", and the "President Unit of the Vibration Association". It also hosts the "Henan Provincial Industrial Design Center", the "Henan Provincial Engineering Technology Research Center for Intelligent Online Screening Systems", and the "Xinxiang Municipal Engineering Technology Research Center for Fine Screening". The company has been granted more than 500 invention, utility model and design patents, has received the "Science and Technology Achievement Award" issued by the Ministry of Industry and Information Technology, and has participated in drafting four "National Standards".
Gaofu's product portfolio covers several series and hundreds of varieties, including vibrating screening equipment, conveying equipment, coal crushing equipment, filtration equipment, and automated material handling systems. Its main products include vibrating screens, screening machines, vibrating sifters, rotary vibrating screens, ultrasonic vibrating screens, linear screens, air flow screens, gyratory screens, roller screens, dewatering screens, bar screens, vacuum feeders, dust-free feeding stations, ton bag feeding stations, feeding systems, automatic powder feeding systems, automatic slag discharge filters, leaf filters, clay filters, toothed roll crushers, coal crushers, and other equipment. These are widely used in many industries such as food, pharmaceuticals, chemicals, metallurgy, building materials, mining, thermal power, and environmental protection, earning the trust and praise of over 10,000 customers worldwide.
Gaofu products are not only popular in Greater China but are also exported to more than 100 countries and regions, including Russia, Canada, the United States, New Zealand, Japan, Brazil, South Africa, etc. The company adheres to its mission: "Enhance material quality and efficiency, meet customer needs", walking side by side with customers for harmonious and win-win cooperation. Today, Gaofu has become an approved supplier to many Fortune 500 companies, including CNPC, Sinopec, Sinochem Group, China Resources Group, Sinopharm Group, COFCO Group, China National Building Material Group, China Aerospace, and Jinchuan Group.
Gaofu Machinery – Global No.1 in Vibrating Screen Sales. In May 2024, Frost & Sullivan, an international authoritative advisory firm, based on its research on the global vibrating screen market and calculated according to global vibrating screen sales volume in 2023, issued a market position confirmation certificate to Gaofu Machinery.
