Food and agro processors produce wet by-products every day: spent grain, starch cake, rice bran, fish meal and distillery residue. They spoil quickly, smell and cost money to move. Drying turns them into stable products that can be stored, sold or used as feed.
What the food and feed industry asks of a dryer
- Temperature control. Proteins, starch and fats can be damaged by too much heat.
- Hygiene. Surfaces that touch the product must be easy to clean, and the material of construction matters.
- Odour. Fish meal and spent grain smell strongly while drying. The vapour must be captured, not vented.
- Even drying. Uneven moisture inside a batch invites mould in storage.
- Sticky feed. Many of these materials turn tacky in the middle of drying.
How a paddle dryer addresses them
Heat reaches the product through jacket and shaft surfaces, so the heating medium, which may be steam, thermic fluid or hot water, never touches the food. Hot water or low-pressure steam can keep surface temperatures moderate. The machine is enclosed, so vapour goes to a condenser or scrubber and not into the plant. Slowly turning, self-cleaning paddles mix the product continuously, and a plug flow design keeps material moving from inlet to outlet without back-mixing, which helps evenness.
For food duty, AS Engineers offers stainless steel in SS304 and SS316, with surface finish options up to electropolishing, and can build vacuum versions where lower temperatures are needed.
Materials AS Engineers lists
In agriculture and animal feed: DDGS (dried distillers grains with solubles), rice bran and fish meal. In food and beverage: starch. Spent grain also appears in its food, pharma and starch group. Which of these suits a given installation depends on moisture, fat content and the quality target, so each project is checked on the actual material.
Things to settle early
| Question | Why it matters |
|---|---|
| Final moisture target | Decides storage life and how far to dry |
| Maximum product temperature | Protects quality and nutrition |
| Fat or oil content | Affects stickiness and fire safety |
| Hygiene standard | Sets the finish, seals and documentation |
| Where the vapour goes | Decides the condenser and scrubber design |
| Throughput and operating hours | Sets the size |
What a food line looks like
A typical line has a feed hopper and screw feeder, the paddle dryer, a condenser or scrubber for the vapour, a conveyor to take the dried product away, and optional bagging. A heat source such as a steam boiler, thermic fluid heater or hot water generator supplies the heating medium.
Test before you buy
Food products are sensitive to how they are dried, so a trial pays for itself. AS Engineers runs pilot trials on a 25 kg/hr paddle dryer, at its works or at your site, for a nominal fee that is waived on order. Request a pilot trial.
Related guides: starch and food residue drying approach, paddle dryer selection criteria and paddle dryer vs rotary dryer.
Related reading
- Sludge dryer manufacturer
- Materials we dry
- Sludge Treatment Equipment Buyer Guide
- Sludge Volume Reduction Guide | Paddle Dryer
- Paddle Dryer for PET Chips, Polymers and Resins
- Industries we serve
More from AS Engineers
See the full range on paddle dryers for the food industry at theasengineers.com.
For wider sludge background, read the industrial sludge management guide on sludgedryer.in, AS Engineers’ sludge drying resource.
- B.E. Mechanical · GTU (2018)
- PGDBA, Operations · Symbiosis
- With AS Engineers since 2019
- Writes on paddle dryers, sludge drying & blowers
Karan Dargode leads operations and environmental health & safety at AS Engineers, an Ahmedabad-based manufacturer with over 25 years of experience in centrifugal blowers, industrial fans, paddle dryers, sludge dryers, and air pollution control equipment. He joined AS Engineers in July 2019 and has spent over six years building operational systems that support the company's engineering and manufacturing work.
