With the growth of the fishing farming businesses, establishing the right and appropriate equipment for processing fish feed that can produce feed of high-quality that will help grow fish is essential to encourage the sustainable growth of the fish farming.
Fish Feed Crushing Technology and Equipment
Based on the biological characteristics and requirements for living conditions, in order to ensure the best efficiency of feed conversion and lessen the pollution of the water that is caused by the fish food, the fish’s feed must be simple to digest and absorption by fish. Similar to the feed material smaller particle size indicates the large area of contact with the digestive enzyme which increases the digestion of nutrients. Therefore, creating digestible feed using a small particles is one of the best ways to increase the utilization rate. Different species of fish in different growth stages have different requirements for the size of feed particles so, choosing the correct crushing equipment and technology is vital.
1. Crushing Technology
The crushing process consists for crushing prior to dosing, that is called pre-grinding. It also includes crushing following dosing that is post-grinding or a combination of both. The method of crushing prior to dosing is mostly used for freshwater fish feed production of adults and the crusher machine is able to be used according to what the material is of good quality used to get the most economical use.
But, pre-grinding comes with the following insufficient
- Exchange of materials consume some time, and will impact the crushing capacity of a unit.
- Small particle size can increase areas of the raw material’s surface which makes the materials less pliable and moist and causing them to cak and affecting the efficiency of dosing.
- In the formula of fish feed there are a variety of raw materials that are made up of high protein as well as high fat. The fat can block the crusher.
Post-grinding technology is a solution to the issues that pre-grinding faces. Grinding is a great mixing process of materials that eliminates the possibility of feed materials clogging. The grinding machine used to crush after dosing needs been designed to crush the hardest feed material.
The combination of post-grinding and pre-grinding is particularly beneficial when it comes to materials that require micro-grinding. Coarse grinding is the primary process; mixing the ingredients is the next step of process, which allows for even mixing raw materials as well as micro-grinding. The final step in processing involves transferring the materials that have been well mixed into the micro-crushing machine for the crushing process. Since lots of heat will be generated during the micro-grinding process the material with heat sensitivities must be included when mixing after grinding. Also, the different density and speed of suspension of materials could cause to gradate and cause unevenness. As a result it is essential following the grinding.
2. Crushing Equipment
There are a variety of crushing equipment for grinding fish feed such as hammer mill vertical hammer mill water-drop crushing machine disk mill, micro-grinding machines and ultrafine grinding. Hammer mill is highly efficient by using its 2 4mm sieve to turn feed material into pieces with an average size of 1200 um and its 1 mm pores can turn materials into pieces with a diameter of 500-600 um , which is the perfect particle size for adult freshwater fish. However, the hammer mill does not work well for grinding fine and processing raw materials with high moisture.
Vertical hammer mills have a greater efficiency of operation than a the hammer mill because it is equipped with a rotor that functions as a fan. However it’s not as efficient for fine grinding.
Water-drop crushing machine features an crushing chamber that utilizes a double-grinding. It can finish fine, coarse and micro-grinding with an increase of 15% in capacity and a particle sizes of 100 to 500um. It is the most suitable machine to crush fish feed in general.
To get an amount of particle that is smaller then 500ums, both a mill and a grading screening screen can be utilized together. 60 to 100 um of particle size could be achieved using a micro-grinder that air-grades The minimum particle size for fish’s first feed is 10-20 um, which is milled by a colloid grinder.
Fish Feed Mixing Technology and Equipment
In order for fish to get complete nutrition, particularly young fish, food ingredients must be properly mixed. A proper mixing technique along with the right equipment can be of vital importance.
- Horizontal-type, helical blade mixer and double-shaft paddle mixers are utilized in feed mills that are all-around for their compatibility.
- In the post-grinding method it is recommended to have two sets of mixing equipment. One is used prior to crushing, while the second is used following crushing to ensure a uniform mixing of the final powders.
- The moisture content of pellets has a major influence on pellet feed processing capacity, quality, and stability in the water therefore, the water-addition device is essential during the mixing process to mix water uniformly into feed materials in a form of atomazation.
- The friction motion during mixing feed materials are prone to carrying electrostatic charge, which will affect the mixing uniformity. Fortunately, the ground connection as well as anti-static agent will solve the issue effectively.
Fish Feed Conditioning Technology and Equipment
The purpose of conditioning fish feed is used to gellate the starch, reduce proteins as well as soften raw materials with heating-moisture treatment in order to ensure the highest quality of pellet fish feed, with high digestibility and stability. There are two types of methods for conditioning that are used: conditioning prior to fish feed pelleting, and conditioning following fish pelleting. The conditioning equipment comes with multiplex conditioners, curing tanks extruding conditioner (conditioning prior to the pelleting process) as well as stabilizer (conditioning after pelleting) and so on.
- Multiplex conditioner: It employs an organized arrangement of three or two double-jacketed conditioners in order to increase the duration of conditioning the powder material in order to increase the performance, however, it is essential that a certain amount of water in powders must be provided. The curing tank follows the same operating principle as the multiplex conditioner. But they all consume too much space and the product is not able to achieve the efficiency of the first-in, last-out.
- Extruding conditioners use high temperatures and high pressure to create an increase in the resistance to water of fish pellets. This type of conditioning has no need in terms of feed particle size and formula, but at simultaneously, this method allows you to make use of low-cost raw materials, and decrease costs. It is a great treatment process for mills that feed fish, with a excellent prospects.
- Stabilizer condition: after the pelletization of fish feed the pellet is heated and is then placed in an insulation vessel, which uses its own heat and moisture as well as the heat created by steam within the jacket to increase digestibility of fish feed pellets as well as durability in the water.
Fish Feed Pelletizing Technology and Equipment
Technology and machinery for Pelletizing are a major aspect that affects the quality of fish feed.
1. Fish feed pellet mill
The efficiency of a fish feed pellet mills is vital to high-quality fish feed pellets. With regard to die size and compression ratio, the mill for fish feed should be equipped with an extremely thick die and a high compression speed.
2. Fish pellet feed extruding machine
Extruded feed is a type of premium fish feed. Fish feed extruding machine can be used to make floating pellets of fish feed and sinking fish pellet feed as well as floating-sinking fish pellets to meet the different needs of different fish species for their food.
3. Fish feed pellet cooler
The process of cooling the pellets that are made for feed with high temperatures and high humidity is important for efficient for pellet storage and packing. However, the quick cooling is not possible as it can cause cracks to the pellet’s surface which weakens the water resistance property in pellets. Horizontal and counter-flow pellet coolers are the two kinds of cooling equipments that provide the best cooling properties.
Fish Feed Liquid Coating Technology and Equipment
In addition to the fat present that is present in feeds, this extra fat has to be added to the pellets for fish feed in order to provide enough fat acid to the facility production and growth of fish. The coating of fat for pellets for fish feed is possible prior to the pelleting process or after. However, heat-sensitive ingredients, like amino acids, vitamins enzymes, amino acids etc. are to be added to pellets of fish food by liquid coating equipment immediately after the pelleting process to ensure their effectiveness.
Technology for coatings has developed significantly to ensure high quality fish pellets for feed and prevent pollution of water. Based on the principle of operation the liquid coating machine is classified by vacuum infusion coater spraying atomization coater, and a centrifugal coating machine for atomization.
- Vacuum-infusion coater The coater has a vacuum inside the coater. During the time that dried material starts rolling and moving the heat-sensitive substances that get sprayed onto the coater are absorbed into the an unsecured structure of the dry material.
- The coater spraying the atomization process: fat and nutrients are micro-granulated with the sprayer, and then spraying onto the fish feed surface.
- Centrifugal atomization coating machine This kind of machine makes use of the centrifugal force to micro-granulate the additives that coat the pellets of fish food.
- Electrostatic coating is a different technology for coating pellets of feed that was developed by food processing technology. It helps the liquid to atomize to completely coat pellets quickly.