Hollow paddle dryer

Hollow paddle dryer

Paddle dryer working principle:

The hollow blade dryer is mainly composed of a jacketed W-shaped housing and two hollow blade shafts and a transmission. Hollow blades are arranged on the shaft, and the rotary end of the heat medium is introduced at the shaft end. The heat required to dry the moisture is conducted to the material by the inner wall of the jacketed W-shaped groove and the hollow blade wall. During the drying process, the hollow shaft with hollow blades agitates the material while heating the material, thereby updating the heating surface. It is a continuous conduction heating dryer. The heating medium is steam, hot water or heat transfer oil. The heating medium is introduced into the casing jacket and the two hollow blade shafts, and the materials are heated and dried by conduction heating, and the hollow shaft structure of different materials is different. The material is added by the feeding port, and under the stirring action of the two hollow blade shafts, the interface is updated, and at the same time, the material is pushed to the discharge port, and the dried material is discharged from the discharge port.

During the drying process, the hollow shaft with hollow blades agitates the material while heating the material, thereby updating the heating surface. A continuous conduction heating dryer. The heating medium is steam, hot water or heat transfer oil. The heating medium is introduced into the casing jacket and the two hollow blade shafts to heat and dry the materials in a conductive manner, and the hollow shaft structure of different materials is different.

The heat sensitive material can also be dried under special conditions and the solvent can be recovered during the drying process. It is commonly used for drying or cooling materials such as carbon black, light calcium carbonate, barium carbonate, nitrile uric acid, gypsum, clay, manganese dioxide, nylon and polyester chips, polyethylene, polypropylene (recovery solvent). The machine is suitable for handling various materials with good thermal stability such as paste, granule and powder.


1. The device has a compact structure and a small footprint. It can be seen from the structure of the device that the heat required for drying is mainly provided by a plurality of hollow blade wall surfaces densely arranged on the hollow shaft, and the heat transfer amount of the jacket wall surface is only a small portion. Therefore, the heat transfer surface of the unit volume equipment is large, which can save equipment footprint and reduce capital investment.

2. High heat utilization rate. The heat required for drying is not provided by hot gases, reducing the heat loss carried away by the hot gases. Due to the compact structure of the device and the small number of auxiliary devices, the heat loss is also reduced. The heat utilization rate can reach 80%-90%.

3. The wedge-shaped blade has self-cleaning ability, which can improve the heat transfer effect of the blade. The dispersive force generated by the combined movement of the inclined surface of the rotating blade and the particle or powder layer makes it easy for the material attached to the heating ramp to be automatically removed, so that the blade maintains an efficient heat transfer function. In addition, due to the reverse rotation of the two-axis blades, the material is alternately segmented (when the two-axis blade is closest to each other) and the material is expanded (the farthest distance between the two-axis blades), so that heat transfer The material near the surface is stirred agly, improving the heat transfer effect. The wedge-type paddle mixer has a high heat transfer coefficient of 85-350W/(M2·K).

4, the amount of gas is small, can reduce or save some auxiliary equipment. Since no gas is required for heating, the amount of gas used in the drying process is greatly reduced. A wedge-shaped paddle dryer requires only a small amount of gas to carry the evaporated moisture. The amount of gas used is small, and it is only necessary to satisfy the drying system temperature, the drying system does not condense dew.
Due to the small amount of gas, the gas flow rate in the dryer is low, and the dust emitted by the gas is less. The gas dust recovery of the system after drying is convenient, the size of the cyclone separator can be reduced, and the bag filter can be omitted or reduced. Gas heaters, blowers, etc. can be scaled down, saving equipment investment.

5. The material has wide adaptability and the product is even and dry. The dryer is equipped with an overflow weir to adjust the amount of material retained in the dryer according to the nature of the material and the drying conditions. The material retention in the dryer can reach 70%-80% of the volume of the cylinder, and the residence time of the material can be increased to meet the drying requirements of the difficult-to-dry materials and the high-moisture materials. In addition, the feed rate, shaft speed and heat carrier temperature can be adjusted to arbitrarily select the material residence time between minutes and hours. Therefore, it is suitable for materials that are easy to dry and difficult to dry. The moisture content is only 0.1%, and there are industrial application examples. In addition, although there are many stirring blades in the dryer, the materials are uniformly mixed. However, the material flows in the dryer from the feeding port to the discharging port, and the piston flow flows substantially, the residence time is narrow, and the product is evenly dried.

6, suitable for a variety of drying operations. It has been mentioned that the wedge-shaped paddle drying can adjust the drying process conditions by various methods, and its operation is easier to control than the fluidized bed drying and airflow drying operations, so it is suitable for various operations.

7. Ruidao patent—The hollow blade dryer is equipped with the double-inserted air lock device produced by our company and can work continuously under vacuum.

8. According to the abrasiveness, compressibility, internal friction, external friction of the powder material and the continuous change of various properties of the material with continuous removal of moisture or solvent, the corresponding blade structure is the core of the hollow blade dryer. technology. For specific materials, special test methods are used to determine the corresponding blade structure. It is the proprietary technology of Ruidao Company, and the technology has not been transferred to the outside.

Hollow paddle dryer Application range:

The machine is suitable for processing various materials with good thermal stability such as paste, granule and powder. Under special conditions, the heat sensitive material can also be dried and the solvent can be recovered during the drying process. For example: “modified starch” has a water content of 30% before drying, and the water content of salt wastewater after drying is 5%, and the treatment amount is 1800 kg/h.

The project integrates drying, mixing and reaction into the integrated main machine, which realizes the technical breakthrough and innovation of the equipment structure development while meeting the needs of the owner’s process.

The technology research and development center of Ruidao (Luoyang) has developed a RD suitable for the environmental protection industry based on the hollow blade dryer after a small-scale drying test on various sludges. The technology and equipment of multi-layer multi-stage multi-effect dryer.

The hollow blade dryer test machine manufactured by our company is for users to do various material experiments. Welcome to visit the material drying process demonstration. Please refer to the following table for more application areas:

Contact Us

Luoyang Ruidao Drying Engineering Co., Ltd.Contact: Xu Manager
Mobile: 86-13849965155
Tel: 86-0379-60852881
Email: ganzaodao@163.com
Address: South Section of Dingding Road, Xigong District, Luoyang City

industry category

Material name






Chemical Industry

Humic acid

soda ash

NPK compound fertilizer



White carbon black

Carbon black


Oxidized sodium fluoride


Magnesium carbonate

Silicon carbide

Sodium cyanide

Aluminum hydroxide


Calcium sulfate


Molecular sieve



Petrochemical industry

Polyolefin powder

Polycarbonate resin

High and low density polyethylene

Polyphenylene sulfide


Polyacetal granule





Propylene-based resin

Engineering plastic

Polyvinyl chloride

Polyvinyl alcohol





Styrene-acrylonitrile copolymerization


Feed industry

Apple pomace

Soy sauce residue

Feed additives

Bone-based feed


Food scrap

Tangerine skin


Chicken bone feed

Fish me

Bioslag mud





Environmental protection industry

MSG factory waste

PTA sludge

Sugar factory waste

Electroplating sewage sludge

Boiler soot

Pharmaceutical factory waste

Fly ash

Food Industry

Modified starch


Cocoa beans

corn kernels







Technical Parameters:







Heat transfer area






Rotating speed














Effective volume






steam pressure







Water evaporation







Dimensions (2r*1)






Hollow paddle dryer spare parts: rotary joint

rotary joint

These rotary joints are specifically designed for the double cone drying equipment in the drying industry. It adopts a reliable spherical friction sealing structure, which can automatically adjust the center and automatically compensate, but it has the advantages of low rotation precision and poor concentricity; there are only four parts inside, this simple and effective structure makes it More convenient maintenance; reliable material assurance and polished spherical and bottom planes provide sufficient service life.

The paddle dryer consists of:

1. Power transmission part: mainly composed of motor, reducer, drive gear, driven gear, and inter-shaft gear. Its main function is to transmit the power of the motor to the agitating part of the main shaft to make it run within the rated speed range. It can also select the variable frequency speed regulation or electromagnetic speed regulation configuration for variable speed operation according to user requirements.

2. Spindle stirring part: mainly composed of two hollow shafts and several wedge-shaped hollow blades on the surface thereof. Heat transfer (heating or cooling) medium (steam, water, oil, etc.) return pipe is arranged in the hollow shaft, and rotary joints at both ends or single-end configuration are the interfaces for the medium to enter and exit. During the operation, the spindle agitating part stirs, pushes and heats or cools the material.

3. Bearing body part: At the two ends of the main shaft, a total of three or two bearing bodies are arranged, which are composed of bearing, bearing seat, bearing cover, sealing packing, packing gland and inspection cover. The power end is equipped with two main bearing bodies, the main bearing body is the main support point of the main shaft and serves as an axial moving point. The auxiliary bearing body is set to prevent the shaft head from being excessively deformed. The non-power end bearing body can freely expand and contract in addition to the bearing point of the main shaft. Each bearing body is provided with a cooling structure of the bearing.

4. The discharge adjustment mechanism is mainly composed of an adjustment plate, a rotating shaft and a positioning member.

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