Download manuals for APV pumps, heat exchangers and homogenizers here. As one of the most energy intensive processes used in the dairy, food and chemical .. The reader is referred to the APV Corrosion Handbook, as well as the. pigments to proteins, as well as minerals to dairy products. Because of the spectrum of duties required, there is a great variety of dryers available. The.

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This can result in reduced quality due to changes in color, taste or other functional properties. Recovered solvent is bled off at 16downstream from the scrubber recirculation pump 14 at wpv controlled rate based on scrubber liquid level.

APV Dryer Handbook

If deposits are seen on the lower walls or cone, the vane rairy may be too close to vertical. By using fluid bed drying and cooling of the formed agglomerates, it is possible to combine the entire agglomeration process into one continuously operating unit. The liquid leaves the outer edge of the disc radially into the hot air stream as a flat cloud of droplets.

Therefore, it is necessary to accurately determine the minimum fluidizing velocity for each product.

However, the thermal efficiency of the drum dryer is high in the region of 1. With both types of dispersion dryer, many configurations are available. These spray dryers usually incorporate one or two fluid beds — static and vibrating — for the final drying and cooling of the agglomerated powder. The two principle means of atomization are centrifugal and pressure nozzle — both have their advantages and disadvantages and the choice is dependent on both feed and powder properties of the specific application.

The spray dryer usually has a greater amount of water to remove by thermal methods than other types. On the smaller inspection doors, a special tool can be procured from APV. The operating handboik as described earlier, is extended, with exhaust gas from the baghouse being scrubbed and cooled in a condenser 13 using cooled solvent from an external plate heat exchanger 15 as the scrubbing dsiry.

During processing, air velocities are adjusted so that fine, unagglomerated powder is blown off the fluidized layer. Thermal dryers, therefore, are an important unit operation in many industries. This settling can be avoided by opening the secondary air inlet valve adjacent to the cyclone base. Generally speaking, the residence time in fluidized bed dryers is measured in minutes and in the pneumatic dryer in seconds.


The final drying can then be hancbook by a spin flash or pneumatic dryer. The rate of drying can affect the density, since the surface of the particle can either retain its initial shape case hardening or shrink as the internal water evaporates.

There are three other factors which can limit the inlet temperature: Wherever possible, through-air circulation is used as opposed handbiok transverse air flow.

All of these characteristics account for their increased demand in recent years. The simplified schematic shown in Figure 25 illustrates a possible configuration of a closed cycle Spin Flash dryer. Typical single pass dryers of modular construction are illustrated in Figures 11 and As a rule of thumb, for every degrees rise in inlet temperature, the outlet temperature should be raised by 12 degrees.

APV Dryer Handbook

This article describes the Spin Flash dryer, shown in Figure 21, as one option available for continuous powder production from pastes and filter cakes without the need for grinding. This generally permits high-rate drying, whereas in other types of dryers, lower temperatures would be necessary and correspondingly larger and more costly equipment would be required.

Here again, the nature of the feed is an important prerequisite for efficient drying. To raise the blend temperature, an automatic valve in the hot air mixing duct is opened by the controller. While the condition of the feed in the pneumatic dryer is somewhat less critical than that in the fluid bed dryer — owing to the fact that it is completely entrained — it is still necessary to use backmixing techniques, on occasion, to produce a suitable feed.

However, by its definition, a spray dryer requires a fluid feed material to allow its atomization device to be employed. For these powders, the optimum cyclone pressure drop is around 8 inches w.

To get a finer particle with a centrifugal atomizer, you need to run the wheel at a higher speed. Poor atomization can also be indicated by a narrow ring around the dryer wall level with the atomizer wheel, or by speckled deposits on the lower walls and cone of a nozzle spray dryer. Protein, pigments, iron oxide, crystals Inert: As it does so, it forms a thick, gel-like mass which resists further penetration of water. An alternative approach to agglomeration is referred to as the re-wet method.

Generally, these extruders operate with rubber covered rollers moving over a perforated die plate with feed in the form of pressed cakes, or more usually, as the discharge from a rotary vacuum filter. At the end of the production run, the total volume of liquid in each stage of the scrubber can be measured. A lower velocity will tend to reduce the final dried particle size carried out of the chamber.


This low pressure drop is not really detrimental to collection efficiency, since higher fat products tend to be easier to collect than low fat powders.

A very brief reduction in handbbook feed rate will result in overwetting of the material with consequent deposit formation in the chamber. Alternative configurations of spray dryers showing A tall form type and B conical As an alternative, the two-fluid nozzle with external mixing is used for a variety of abrasive materials.

It also should be remembered that standard fan arrangements are not equally suitable for a variety of materials of different densities. If dair air flow is reduced, either by choice or due to a problem, the handbbook rate of the dryer handblok also be reduced. The cooling air temperature is controlled automatically by mixing some air from the main air heater, with cold air taken from the upstream of the same heater.

Start-up, shut-down and operation of the fluid bed agglomerator are greatly simplified due to the stabilizing effect of the powder volume in the re-wet zone. This will retain the same relative humidity in the outlet air and hence, the same powder moisture.

This is achieved by a cascade control from a feed vat level sensor to the inlet temperature controller set-point. Feed solids content is another factor that impacts flow rate. This would make selection of a fluid bed dryer completely unrealistic and probably would suggest a conventional rotary dryer for the application. Typically, this duty would be performed in a large spray dryer.

This arrangement considerably increases the residence time within the dryer and is particularly useful where the product has poor diffusion characteristics. When the diffusion characteristics of the material or other process considerations call for extended residence times, these machines, no doubt, will continue to find application.

Dairy a;v Sweeteners Baby formula Detergents Calf milk replacer Enzymes Flavor compounds Herbicides Fruit extracts Egg albumin Maltodextrines Starch Corn syrup solids Cocoa mixes Natural gums Insecticides In most cases, the agglomeration can be accomplished using only water as a re-wet media. There is sufficient agitation handgook the bed to obtain a satisfactory distribution of the binder liquid on the particle surfaces and to prevent lump formation.