I need help on extrusion of fish sinking feed .I reach 50:50 of sinking and i need 99 % but i just can not make feed to sink is it from formulation or from adjustments of the extruder.
I'm glad that with my problem we open something that is interested and good to share each of us
For any help that i can do and with my knowledge for extrusion please post and we can keep these channel open for discussion.
Happy Holidays
Denis
sinking feed use pelletmill or twinscrew extruder, for the latter one needs to count on serious investment
Urs is a highly respected expert in the industy, as such he is correct by mentioning that with 17 to 18% of water in a pelleting process good gelatinization is just not possible. There is not sufficient shear in this process to get better result.
here the expander technology can be of interest. Placing expander on top of pelletmill will provide shear and one still can do without dryer. Tests can be done at the FeedDesignLab (FDL) in Wanssum Netherlands where an Almex AL150 expanderi s available on top of pelletmill.
Dear all!
Many things are possible the target should always be that of sustainability first later would be profitability. For that R&D is required, new opportunities needs to be explored and discussed. If improved and affordable technology is an available option then multi culture and multi uses of machine to grow variety of food items would also generate more assured returns and that too at reduced risk factor.
Thanks
PP AMBALKAR
Dear All,
I like to have the details on suitable type of feed for Mangrove Crab.As you may please be aware that, mud crab require soft pellet and they initially chew the pellet and break the feed with mandibles .
The feed should not break and pale ability There are more potential for crab feed in many SE Asian countries such as India, Srilanka,Vietnam, Indonesia,Philippines etc., How to make such feed and what type of machinates required to make such feed
Dear Matteo
First of all let me thank you for your interest in the problem.
We use wary simple formula
wheat flower,………………….. 5 %
soya(44%)……………………… 48%
sunflower seed meal,………… . 3 %
Triticale……………………….. 25%
soya protein(65%)…………… 2%
fish meal(70%)…………………….. 3%
Oil(animal origin) ……………….. 2%
CaCo3 ……………………………. 1%
Salt ……………………. 0,5%
fine corn starch ………… 10 % because like i read that 10 % fine starch is for sinking and everything more than 20 is for floating?
Water is added in mixer (we don’t have steam generator)and is 35 to 40 %
The parameter of the extruder are like these
First heating zone 70 degree
Second heating zone 90 degree
Third heating zone 95 degree
Speed of the extruder 25 Hz(approximately 600 rpm)
Opening dice 6 mm(one hole)
Like these we have 80 % sinking and 20 slow sinking after 20 min we need fast sinking
The fish feed is for Carp
Thanks in advance
Here are a few key takeaways I see with your issue to create consistent sinking fish feed.
1. You still need to reduce starch in your overall diet formulation if you want the feed to sink. The replacement ingredient, triticale, you are using in place of wheat flour, is still almost all starch. Starch will assist in pelleting but also expands your pellet making it float. You can substitute for an ingredient that is low in starch and has a higher fiber content. I believe wheat bran was mentioned in previous posts.
2. You also will need to add more fat in the diet formulation. This will assist in the sinking of the fish feed. You can use mechanically extruded and pressed soybean meal, which has a higher residual oil content (5-9%). This is also a good source of energy in the diet, meaning you can reduce or replace other higher cost high energy ingredients.
3. Reducing the water in the formulation from 35-40% down to 20-25% will assist in several things. First, you will get a better cook and mixing of the ingredients during extrusion. Second, adding too much moisture will help to stabilize the pellet as well.
To comment further on the process itself, the temperature and amount of time the ingredients are cooked will make a difference . Many ingredients in your formulation have already been processed from their raw state and do not require too high of temperature to process, With that being said, the processing temperatures you are using seem a little low, meaning you will not get a sufficient cook. In addition, increasing dwell time may help with pellet expansion, which could be attributing to the floating versus sinking issue.
Overall, you should reduce the starch and moisture and increase the fat in your overall formulation and make proper adjustments to your process to achieve a more uniform sinking fish feed. It is important to both understand the nutritional quality of the end product and how extrusion affects this. If you have any additional questions, I would be happy to discuss this further with you.
I would also suggest that we dont have a detailed screw configuration, Denis has the configuration changed?
is this the same machine you have used for years?
are the screws and liners worn?
has the formula changed?
could you use hot process water say 60-70c ?
you mention 600rpm shaft speed, is this the input shaft at 25htz or the actual extruder shaft speeds?
my thoughts are that you seem to be only using mechanical energy to create cook it does not sound like you are using thermal energy which may be to aggressive. even a single screw would not turn anywhere near this speed to give 700g/L feed density.
Please, I would love to know what causes blockage while extruder is working.because we use single screw extruder and we do additional seiving before sending for extrusion but each time we produce it works for about 45mins then it stops coming out in pellets but in worms shape form and then blocks. How do I troubleshoot? What should I do?
NKWOCHA OBED what is the head temperature? What is the formulation? There are many blockage causing items and a suggestion would need more information.
The head temperature is 150 °C, for the formulation Fish-20,soya-20,corn-15,gnc-15, cassava-10,wheat-15 and the rest are the additives. But what's the effect of the temperature and formulation?
NKWOCHA OBED the temperature is probably far too hot. I would expect to see these kind of temperatures extruding cheetos or other light density products. Do you have the ability to cool the heads or add 1% oil into the conditioner? How much water are you using? It sounds like the cook is out of control. Can you use a less aggressive screw configuration or slow the extruder shaft?
I thought temperature at 150°C is ok to cook and kill what ever it needs to kill in the feed. The water 15-20% is used to mix the feed and a little into the conditional. I have never poured oil into the extruder, the oils are used for coating. I can regulate the shaft that controls the feeder but not the screw. What temperature do you suggest is ok? The water percentage and how can one control the screw?
If you don't mind me asking, what extruder are you using? Do you have water flow meters connected to the extruder water supply? Adding water to the mix is really old technology and not accurate enough as you will probably rehydrate the formula unevenly.
Are you trying to make floating or sinking? I would cool the extruder to give around 90 as a final head temp and see how you go. take 0.5% from coating and add into the conditioner close to the extruder inlet this will also help.
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