Pet Food Dryer

The pet feed drying machine is a continuous drying equipment used in mass production. It is used for drying sheet, strip and granular materials with good air permeability. It is especially suitable for dry and heat-sensitive materials with high moisture content.

This series of pet animal feed dryers has the advantages of high drying rate, high evaporation intensity, and good product quality. Let’s take a look at its working principle and form.

(1) Dryer structure:

The mesh belt pet food dryer consists of an organic head, drying section, tail, mesh belt, transmission device, feeding and distributing equipment, air inlet duct, air outlet duct, fan, heat source equipment, conveying equipment, etc.

(2) Working principle of pet food dryer:

Dryers are currently divided into single-layer and multi-layer, single-stage and multi-stage types, but the working principles are basically the same.

• The materials in the hopper are evenly spread on the mesh belt by the feeder and move forward with the conveyor mesh belt.
• The hot air in the drying unit passes vertically through the material layer to dehydrate the material.
• The thickness of the material layer on the mesh belt is determined by factors such as material properties, cloth methods, and dry explosion temperatures.
• The thickness is generally adjusted within the range of 20-100mm. The mesh belt is 12-16 mesh and is made of imported PET woven material. Three-dimensional mesh belts can also be used as needed. It is driven by the transmission device to move in the drying box.
• The drying section is composed of several modular units, and the hot air in each modular unit circulates independently.

During the use of the pet food dryer, the following factors will affect the drying quality of pet feed:

• Operating temperature (as high as possible within the allowable range of the product, and uniform)
• Air humidity (air as dry as possible without reducing the efficiency of the entire system)
• Air distribution (even distribution)
• Drying time (appropriate drying time)
• Product distribution (uniform material layer thickness)
• Product type and quality (physical and chemical properties, shape and size, product ingredients, fat content, bonding state, bulk density)
• The relative relationship between air flow rate, air flow speed and air flow
• . . .

Overall, all pet food dryers work the same way. But in order to let you better understand the working principle of the four-layer dryer, RICH will describe it to you here:

1. The working principle of the four-layer pet food dryer is that the wet feed is evenly spread on the four material layers, and the cold air enters the dryer from the air inlet; driven by the circulating fan, the cold air passes through the heat exchanger and is heated;
2. Then it enters the drying room through the left air duct. The hot air penetrates the four material layers in three ways.
3. Some of the hot air penetrates upwards through the 1st and 4th layers of feed, and part penetrates downwards into the 2nd and 3rd layers of feed. During the process, heat exchange occurs with the feed, and the hot air becomes cold and takes away the moisture in the feed;
4. Finally, from the right air duct, part of it is discharged from the air outlet, and the other part enters the cycle again, while fresh air enters from the air inlet, thus keeping the total amount of air inside the pet food drying machine remains unchanged. (Find RICHI on YouTube)

1. The moisture of the host material should be reduced as much as possible (less than 24% as much as possible), but the puffing degree and appearance quality should be ensured; the host material has less moisture, which can reduce steam consumption;
2. The moisture after drying should be controlled as much as possible (as high as 11%), but the moisture of the finished product must not exceed 10.5%; the higher the moisture after drying, the more steam consumption will be saved;
   • It should be noted that the moisture difference of the materials cannot exceed 2% (the lower, the better to control the moisture after drying, and the more steam can be saved);
   • Pay attention to the thickness of the material layer (preferably no more than 30mm), and it must not be higher than 80mm, as energy consumption will increase significantly;
   • The distributor should distribute the material evenly; ensure that the material layer is uniform, so that the moisture after drying by pet food dryer can be easily controlled and energy consumption can be saved;
   • The air volume must be controlled reasonably and cannot be too small. If the hot air is too small, the hot air cannot penetrate the material and the drying effect will be poor; if it is too large, the material may accumulate in piles, resulting in uneven drying and large moisture differences; both will waste heat energy, it cannot save steam.

Analysis of process control of steam

• The materials entering the pet food dryer should be as high as possible and the hot materials should be dried to avoid the waste caused by cooling the materials before drying. If the temperature of the materials is low, heat energy will be wasted to heat the materials with steam; resulting in waste of heat energy. ;
• Use low-temperature drying as much as possible during the drying process. Low-temperature drying not only saves steam, but also ensures product quality;
• Extend the drying time as much as possible, preferably more than 30 minutes. The longer the drying time, the more steam is saved;
• The process arrangement must not create bottlenecks in other places, causing downtime to wait for materials or packaging, resulting in increased steam consumption;
• The screening effect should be good (at least a 24-mesh screen, preferably a 30-mesh screen) to avoid mold blockage or fiber hanging, which may cause downtime and increase steam consumption;
• The warehouse to be expanded must be made of stainless steel, otherwise rust will cause mold blockage, affect the continuity of production, and increase steam consumption of pet food dryer.

Analysis from the perspective of operation:

• Pay attention to steam leakage, especially steam leakage from traps, to avoid wasting steam. Many pet food production companies do not pay attention to this problem, and the proportion of waste is also large. please pay attention to it;
• Pay attention to controlling the air volume of the dehumidification fan (the hot air must be able to penetrate the material, but not cause the material to fly) and the dehumidification temperature (control it at around 65 degrees);
• Pay attention to the tightness of the inner doors of each drying area, and do not allow the hot air in each working area to short-circuit (which many pet food companies do not pay attention to), resulting in a waste of steam;
• Pay attention to the speed of the chain crawler to ensure that the drying time and the thickness of the material layer are reasonable; hot air can not only penetrate the material layer, but also ensure a reasonable drying time and reduce waste of heat energy;
• Do a good job in sealing the pet food dryer to reduce the waste of hot air, thereby saving steam heat energy;
• The production plan is to produce in large quantities as much as possible to reduce the time for changing varieties and reduce the loss of steam;
• Improve one-time production rate, reduce the number of re-productions, and reduce steam energy consumption;
• Full-load production, improve production efficiency and reduce steam energy consumption;
• Accumulate production process parameters. Different pellet diameters, different production capacities, different puffing degrees, and different lengths control the drying temperature of pet food dryer. The smaller the particle diameter, the lower the production capacity, the higher the puffing coefficient, and the longer the pellet length. The shorter the time, the lower the drying temperature needs to be, and the moisture of the finished product should be controlled to about 10% as much as possible to avoid excessive drying, resulting in low yield and increased steam consumption; the higher the moisture of the finished product, the more steam energy consumption can be saved;
• Improve the skills of operators, reduce the number of materials at the beginning and end, reduce the time for changing varieties, reasonably control the moisture content of the mold, reasonably control the temperature of the mold, reasonably control the puffing degree, improve production efficiency, and reduce steam energy consumption;
• Clean the heat exchanger frequently to ensure normal heat exchange and avoid waste; generally clean it at least once a week;
• Frequently clean the miscellaneous materials and powder in the pet food dryer to reduce the heat energy absorbed by the miscellaneous materials and cause waste;
• When changing varieties, pay attention to controlling the opening and closing time of the dehumidifier to reduce waste of heat energy;
• When changing varieties, pay attention to controlling the opening and closing time of the circulation fan to reduce waste of heat energy;
• When changing varieties, the steam valve must be closed in time and there must be an advance amount to reduce waste of heat energy;
• Pay attention to the steam pressure. We need high pressure, dryness and stability, at least 6 pressures. The lower the steam pressure, the higher the energy consumption;
• Pay attention to cleaning the puffing conditioner once a week to remove some agglomerated hard debris and fibers to avoid clogging the mold and hanging the knife, which will cause shutdown and cleaning and increase steam consumption;
• Pay attention to configure the corresponding molds and cutter heads, quickly change molds and clean them, improve efficiency and reduce energy consumption;

Analysis from formula design:

• Using fresh fish meal with good water solubility, the material is easy to puff and evenly puffed, which can reduce the steam consumption of the dryer;
• Use protein raw materials that have good water solubility and are helpful for the expansion rate. The materials are easy to expand and expand evenly, which can reduce the steam consumption of the pet food dryer;
• The formula design is reasonably matched with the starch source; it is conducive to uniform puffing without being too hard, and it can also save drying steam.

If the pet feed factory can do the above work well, I believe it can save heat energy to the maximum extent. It is estimated that the steam energy consumption of your company’s pet extruded feed will achieve unexpected results; I believe that the energy consumption of the pet feed you produce per ton is only about 230 kilograms of steam; greatly saving your production costs.

1. When discharging materials from the multi-layer pet food dryer, be sure to block the discharging opening. The dry materials contain a large amount of water and can easily stick together. If the materials stick together when feeding, the materials will block the inlet, causing the dry materials to not come down and enter the dryer, making the drying operation impossible. In addition, in addition to paying attention to the usual feeding, the operator needs to adjust the dryer accordingly. The feeding port is equipped with a stirring device, which can effectively prevent materials from sticking together and blocking the mouth of the bin.
2. When feeding, pay attention to the quantity requirements. The quantity requirements are mainly determined based on the output of the dry material dryer. If the output is not enough, feeding too much material is not conducive to the work of the pet food dryer.
3. Humidity control. The humidity of different dry materials is different, some are high and some are low. When drying materials, check the humidity of the dry materials and select the corresponding release standards according to materials with different humidity.
4. In order to ensure normal operation, it is necessary to check that the components and fixed parts of the multi-layer pet food dryer are not loosened, with or without abnormal sounds, and troubleshoot them promptly if any faults are found. Check whether the V-belts, chains and other transmission mechanisms are deformed, loosened and worn, and remove them in a timely manner. Adjust the chain fastness, check the electrical safety start and stop, and the device is sensitive, accurate and reliable.

Drying is a very important step in the processing of puffed pet food. Through proper drying with pet food dryer, puffed pet food can achieve better results. So, what should you pay attention to when drying?

(1) Temperature control

In the drying process, temperature control is very important. Generally speaking, the drying temperature of puffed pet food is controlled between 75℃-100℃, subject to the specific pet food formula and drying effect. At the same time, you need to pay attention to temperature changes during the drying process, and try to control the temperature fluctuation range within 3°C.

(2) Time control

Drying time is also very important. If the time is long, the puffed pet food will easily gelatinize, while if the time is too short, the pet food will not be fully puffed. Generally speaking, it is more appropriate to control the time within 20-30 minutes. But the details need to be experimentally determined.

In addition to controlling temperature and time, there are also the following points to note:

• Frequent stirring is required during the drying process to fully dry the pet food.
• The external environment needs to be kept dry to reduce moisture absorption of pet materials.
• Processing and packaging equipment need to be cleaned and disinfected to ensure the hygiene of pet materials.
• After drying, it needs to be left to rest for a period of time to achieve the best taste and extrusion effect.

These are very important links when making puffed pet food. As long as you master these key points, making high-quality pet food will become easy.