1. General description of Sludge Hollow Paddle Dryer
Hollow Paddle Dryer is a horizontal stirring and heat conduction type drying equipment that can work continuously. Its stirring blade is like ship paddle, so it is called paddle dryer. In foreign countries, it is also called slot dryer or stirring dryer.
Needed heat of the dryer relies on heat conduction to heat indirectly, so during the drying period it doesn't need air or little air to take the moisture away. It greatly reduces the heat loss that took away by air flow and the use ratio of heat is improved, so it is a kind energy saving type drying equipment. Paddle dryer is widely used in petrochemical, chemical, metallurgy, foodstuff, pharmaceutical, pesticide industrials and so on for drying powder, granules, filter cake and seriflux materials.
On the basis of a wide research, absorption and digestion of domestic and foreign advanced technology, our company  improved and optimal designed the wedge hollow paddle dryer. It can indirectly heat or cool paste shape, granules, powder and seriflux materials. It can achieve the operation of drying, cooling, heating, sterilization, reaction and low temperature calcinations, etc. In the equipment, the wedge-shape stirring and heat transfer paddle has high heat transfer efficiency and the heat transfer surface self-clean function






2. Structure of Sludge Hollow Paddle Dryer
Take double shafts type for example to introduce the structure (paddle dryers include single shaft, double shafts, and four shafts). It consists of W-shape shell with jacket, upper cover, two hollow shafts with paddles, covers of two ends, swivel joint, flexible metal tubing and transmission mechanism that including gears and chain wheel, etc.
The cores of the equipment are the two hollow shafts and the hollow paddles welded on the shafts. The shape of paddle is wedge-shape hollow hemicycle, inside it can be input heating medium. Except the stirring function, it also is the heat transfer device. Two main heat transfer surfaces of paddle are slope surfaces. When material contacts with the slope surface, granules will slip away from the slope surface with the rotary of paddle. It can make the heat transfer is renewed continuously, so the heat transfer is strengthened. At the triangle bottom of paddle there is scraper blade, it can sweep the material that deposits at the bottom, so it can avoid the dead corner.
There are some requirements for the distribution of paddle and the size of its each part. And at the feeding area, drying area and discharging area, there are not only paddles but also complementary unit, it can ensure the machine works stably, and dry uniformly. Moreover, residence time can be regulated.



3. Working Principle of  Hollow Paddle Dryer

The Hollow Paddle Dryer has a metal wall which separates the process mass from the heat source (steam or hot oil). High thermal efficiency is obtained because the heat from the thermal medium goes directly into the process mass. As the material comes into contact with the heated through and agitators, the process mass is heated via conduction. With an insulated dryer, very little heat is lost. To evaporate 1kg of water only requires about 1.2kg of steam for slurry materials. Exhaust gas is minimal and at a low temperature. Therefore, the volume of non-condensable gas from the dryer, which might require treatment, is minimal.

The dryer is an indirect heat transfer device which utilizes a high degree of mechanical agitation to enhance contact with the product being dried. Evaporation rates per square foot of heat transfer surface are maximized through self-cleaning paddles and the mixing effect. Movement of the process material between the slanting surfaces of the revolving wedge-shaped paddles generates shearing forces, which clean the paddle surfaces and maximize conductivity. Counter rotating shafts move the material away from the walls, cleaning the walls by means of the tab on each paddle. This results in higher heat transfer rates than disc or single shaft designs.

The wedge-shaped paddles, and the intermeshing of the dual agitators, create a localized mixing effect around the paddle. This allows more individual particles in the bed to be exposed directly to the heat transfer surface, thereby increasing the heat transfer rate, allowing the use of smaller equipment.

4. Company Profile
Changzhou Welldone Machinery Technology Co., Ltd is a technical researching & Package solution integrating company based on two real factories (one dryer factory and one granulator factory) which has over 20 years manufacturing experiences. We are now also associating with other factory such as extractor factory, crystallization tank factory, evaporator factory, package machine factory etc to become a business league. We are able to provide more than just a single equipment, but becoming a package solution provider. Our products are widely used in pharmaceutical industry, food industry, chemical industry, environmental protection industry and so on.

Welldone actively participates in international competition, products has been exported to USA, UK, Canada, Russia, Australia, Italy, France, Spain, Japan, Korea, Indonesia, India, Sri Lanka, Malaysia, Viet Nam, Bangladesh, Phillippines, Pakistan, Thailand, Columbia, Ecuador, Mexico, Brazil, Tajikistan, Turkey, Ukraine, Tunisia, Egypt, Algeria, South Africa, Nigeria and so on. We have won the praise of our customers with good quality and high quality service, and established a long-term win-win relationship with our customers

Welldone focuses on technology, institution and cultural precipitation. In new historical time, Welldone will continuously unfold far seeing plan, unceasingly deepen strategic idea and strongly propel production management. Based on the development of enterprises, the growth of multi-security growing way and the wisdom of the workers, Welldone will rapidly upgrade comprehensive competitive power and struggle unremittingly to create itself an innovative and cultural enterprise.