Working Principle

After fed continuously to the top drying plate in the dryer by the feeder, the material is turned and stirred continuously by harrows when the harrow's arm rotates. Then it flows through the surface of the drying plate along the exponential helical line. The material on the small drying plate is moved to its exterior edge and drops down to the exterior edge of the large drying plate underneath, where it will then be moved inward and falls from the central hole to the small drying plate on the next layer. Small and large drying plates are arranged alternately so that the material can go through the whole dryer continuously. The heating media, which can be saturated steam, hot water or thermal oil, is introduced into hollow drying plates from one end and come out from the other. The dried product drops from the last layer of the drying plates to the bottom layer of the shell, and finally is sent to the discharge outlet by harrows. Moisture escapes from the material and is discharged from the humidity outlet on the top cover (or sucked out by the vacuum pump on the top cover if the drying equipment is a vacuum plate dryer). The dried product discharged from the bottom layer can be packed up directly. The drying capability can be raised if the dryer is equipped with supplementary devices such as finned heater, condenser for solvent recovery, bag dust filter, return and mix mechanism for dried materials and suction fan etc. The paste-like and heat-sensitive materials can have their solvents easily recovered and have thermal decomposition and reaction carried out.

Characteristics

(1) Easy control and great adaptability:

1. The dryer can have the best drying process by regulating thickness of materials, rotating speed of main shaft, number of harrow's arms, style and size of harrows.

2. Materials can be heated up or cooled off in each layer of drying plates independently by introducing heat medium or cold medium with exact and easy control of material temperature.

3. Dwell time of materials can be accurately adjusted.

4. Single flowing direction of materials without return flowing and mixing, uniform drying and stable quality. No re-mixing is required. 

(2) Easy and simple operation:

1. Simple starts or stops of the dryer;

2. After material feeding is stopped, the material in the dryer can be discharged quickly by harrows.

3. Careful cleaning and observation of the inner equipment can be carried out through the large viewing window. 

(3) Low energy consumption

1. Low power and energy consumption is required of materials transport system due to the thin layer of materials and low speed of main shaft.

2. The drying by conducting heat has high heat efficiency and requires low energy consumption. 

(4)Good operation environment, recoverable solvents and powder discharge in conformity with standards.

1. Normal pressure type: Due to low speed of air flow inside the equipment and moisture being high in upper part and low in lower part, dust powder couldn't float to the equipment, so there is almost no dust powder in tail gas discharged from the moist discharge port on the top.

2. Closed type: This type of dryers is equipped with solvent recovery device that can recover organic solvents easily from the moist-carrier gas. The solvent recovery device has simple structure and high recovery rate. Nitrogen can be used as moist-carrier gas in closed circulation for flammable, explosive poisonous and oxidizable materials for safety. The dryer is especially suitable for drying flammable, explosive and poisonous materials.

3. Vacuum type: The vacuum plate dryer operating in vacuum is particularly suitable for drying heat-sensitive materials. 

(5) Easy installation and small occupied area:

1. As the dryer is manufactured and delivered as a whole, it can be easily installed and fixed at site only by hoisting.

2. As the drying plates are arranged by layers and installed vertically, the dryer can have large drying area while occupies small area.

Material to be dried

It is suitable for the drying, heat decomposition, combustion, cooling, reaction, and sublimation of the following:

1. Organic chemicals

2. Inorganic chemicals

3. Pharmaceuticals and foodstuff

4. Feed and fertilizers

Technical Parameters

Technical Characteristics:

1. Drying plates

(1). Design Pressure: generally 0.4MPa, Max. 1.6MPa.

(2). Maximum Working Pressure: generally less than 0.4MPa, Max. 1.6Mpa.

(3).Heating Medium can be steam, hot water or conducting oil. Hot water acts as medium when the temperature of drying plates is 100℃; saturated steam of less than 0.4Mpa or steam-gas as the medium when the temperature is 100℃~150℃; conducting oil for temperature of 150℃~320℃; and electricity, oil or fused salt when the temperature is over 320℃. 

2. Material transmission system

(1) Speed of Main Shaft: 1~10 rpm with electromagnetism or frequency stepless conversion timing.

(2) Harrow Arms: 2 to 8 arms are fixed on the main shaft on every layer of drying plates.

(3). Harrow's blades: the blades are linked to the harrow arms and can float together with the surface of the plate to keep contact. There are various types.

(4). Rollers: for the products which easily agglomerate, or require grinding, the heat transfer and drying process might be reinforced by installing roller(s) at the appropriate place(s). 

3. Shell

There're three types for option: normal pressure, sealed and vacuum.

(1) Normal pressure: cylindrical shell or octagonal prism shell with entirety and opening out as the structure. The main pipe for heat medium inlet and outlet can be installed inside the shell or outside.

(2) Sealed: The sealed dryer can bear the interior pressure of 5KPa and is of cylindrical shell. The main pipe for heat medium inlet and outlet can be installed inside the shell or outside.

(3) Vacuum: Of cylindrical shell, the vacuum dryer can bear the exterior pressure of 0.1MPa. The main pipe for heat medium inlet and outlet is inside the shell. 

4. Air heater:

It is usually applied at times of great evaporation requirement to increase drying efficiency.