Designing thought 1 – Low flow rate at high pressure
The spray dry interaction necessitates that a moderately low flow pace of liquid is sprayed into the hot air stream so the important dissipation can happen. Assuming a lot of liquid is sprayed; it will basically tumble to the floor of the chamber and wet any powder that has been stored. Simultaneously it is alluring to have an all around atomized liquid as this boosts the surface region in touch with the drying hot air thus improves vanishing rates.
The issue is that these two attractive variables are in strain with one another. The capacity of an immediate pressure nozzle to atomize the liquid is relative to the pressure the liquid is being sprayed at. The higher the pressure the more prominent the atomization, but additionally the higher the pressure the higher the flow rate.
This problem has prompted the improvement of expert spray drying nozzles that give high atomization at low flow rates. The liquid is separated in a twirl chamber before exit from the opening. With specific spray drying nozzles the twirl chamber is intended to boost atomization to the detriment of flow rate. In this manner significantly more of the motor energy of the liquid is utilized to atomize the spray than in a typical pivotal spin plan nozzle.
By need these nozzles work at exceptionally high pressures, as this is the thing that gives the liquid the fundamental energy to get atomized. Working at such high pressures presents various difficulties as far as nozzle wear.
Designing Consideration 2 – Droplet size
The warmth move, and thus evaporative force, of any system will be an immediate capacity of the surface region introduced to the warming component. On account of spray drying this implies that the more noteworthy the surface space of the liquid being sprayed the faster the water will be vanished from the slurry.
The surface space of a given volume of liquid is contrarily corresponding to average drop size that makes up that liquid. On the off chance that one parts the normal drop size of a liquid, and keeps the general volume of liquid the equivalent, the added surface space of the multitude of drops will twofold. All in all, the more modest the bead size the more noteworthy the surface region and subsequently the more prominent the drying force of the spray drying system.
Thus spray drying nozzles are intended to frame fine drops. They do this by working at high pressures and utilizing the high inner energy of the slurry under such pressures to split it up into a fine spray.
Consistency of drops
It is likewise essential to guarantee that the drops shaped are genuinely uniform in size. Numerous nozzles will create a wide range of bead measures yet this is unwanted in spray drying applications, as bigger drops might not have fluid eliminated and consequently neglect to dry. More medium drops will have their dampness taken out however the leftover powder molecule might be harmed by exorbitant warmth. Therefore spray drying nozzles are intended to give a high level of consistency of droplet size. They have a low relative range of particles – for additional subtleties on relative range and how it is estimated and controlled kindly visit our designing asset segment.
Designing Consideration 3 – Control of Spray Properties
Each unique liquid that will be dried will have an ideal equilibrium of bead size, flow rate and spray plot for proficient spray drying. In addition to the fact that it is imperative to get the equilibrium directly from an energy effectiveness viewpoint, it is likewise significant not to add a lot of warmth to the system as it can, plainly on account of food items, overcook the spray.
The ideal arrangement can fluctuate even between various clusters of a similar liquid. The exact best arrangement just accompanies cozy experience of the cycle and item. The plan is measured thus these can be arranged to change the flow qualities. There are a huge number of various mixes giving a high degree of power over the spray drying measure.
Designing Consideration 4 – Wear and Tear
The disadvantage of spraying at high pressures is that wear on the nozzle is high. This is combined with the way that the liquid being sprayed is for the most part thick or “uneven”. By the actual idea of the cycle the liquid being sprayed is water with particles suspended in it. This implies that the suspended particles are being crushed into the nozzles at high pressure – unavoidably this implies they destroy rapidly.
To counter the issue of quick wear most spray dry nozzles will have tungsten carbide compound whirl chambers however even this just slows the issue. The secluded idea of the nozzles assists keep with bringing down the expense of substitutions, as though a hole is worn then just that part need be supplanted instead of the entire gathering.