PLC Based Food Dehydrator

Project Title

PLC Based Food Dehydrator

Project Area of Specialization RoboticsProject Summary

Foods can be spoiled by food microorganisms or through enzymatic reactions within the food. Bacteria, yeast, and molds must have a sufficient amount of moisture around them to grow and cause spoilage. Reducing the moisture content of food prevents the growth of these spoilage-causing microorganisms and slows down enzymatic reactions that take place within food. The combination of these events helps to prevent spoilage in dried food.

Drying (dehydrating) food is one of the oldest and easiest methods of food preservation. Dehydration is the process of removing water or moisture from a food product. Removing moisture from foods makes them smaller and lighter. Drying food is also a way of preserving seasonal foods for later use.

Hot-air dehydration was developed in France in 1795. Modern dehydration techniques have been largely stimulated by the advantages dehydration gives in compactness; on the average, dehydrated food has about 1/15the bulk of the original or reconstituted product. The use of automation within the food processing industry, has allowed for the continual improvement in production and quality control, including that for dried fruit products.

By monitoring and controlling process variables within a commercial fruit dryer (dehydrator), quality control features such as moisture-content, texture, and colour etc, can be attained. The three minimum process variables within most commercial fruit dryers to achieve successful drying are air-temperature, air-velocity, and relative-humidity.

This project investigates the control of air-temperature in a fruit dehydrator by implementing a PID controller using PLC.

In northern areas of Pakistan food is being dried using an old method (using sun light) which takes weeks for the whole process. While bad weather can also increase the process period and food contamination can spoil the food too. There is a need of such project which can reduce the process period and prevent the contamination on the other hand maintaining its quality.

We have proposed this project to do all the above mentioned work.

Project Objectives

A fully automated commercial food dehydrator which will dehydrate almost any kind of food within hours while on the other hand we will also maintain the quality, color and texture of food. There are alot of domestic food dehydrators are being used in Pakistan market and people are using them to dehydrate and store small quantity of food while we are giving design and prototype of commercial dehydrator which can dehydrate food on large scale and can be used for trading and business purpose. As dehydration is being done by old methods and also risk of food contamination involved. This prototype will replace the old method of dehydration.

Project Implementation Method

This is just the prototype of our mega project. To clarify how it is going to replace the old methods of dehydration of food. We are using small quantity of food for dehydration as a sample or testing purpose to check the efficiency and accuracy of our unit but our mega project design can produce tonnes of dehydrated food within a day. Which includes large heaters and fans including pre processing area for food and large conveyor belts. 

Benefits of the Project

Following are some benefits of our project but are not limited to.

1. Quality dehydrated food production.
2. No food contamination risk involved.
3. Dehydrated food production on large scale.
4. Same quantity of food will be produced but in much less time than method being used by people now a days.
5. A new development in food processing area.
6. Helps improve economic growth of country.

Technical Details of Final Deliverable

https://bit.ly/2VEwSEo

Process control diagram of our project is shown in above given link. There are 3 close loops (Air flow, temperature and humidity) in our project which are being controlled by PLC. There are also 2 open loops only for indication purpose. As it is controlled environment unit we will maintain the temperature of chamber between 50 to 70 degree C.As long as humidity is below given setpoint hot air will circulate in the unit through provided duct due to which less power will be consumed by the unit. When humidity crosses setpoint damper valves will be open for fresh air inlet and hot air outlet both at the same time. After a given time unit will stop its operation and 2 trays with dehydrated food will automatically come out for new batch of food to dehydrate.

Final Deliverable of the Project Hardware SystemType of Industry Agriculture , Food Technologies OthersSustainable Development Goals Decent Work and Economic Growth, Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	34300
PLC	Equipment	1	10000	10000
RTD (Pt 100)	Equipment	2	600	1200
Temperature Transmitter (SRK-2460)	Equipment	2	1800	3600
DC fan	Equipment	1	1500	1500
Damper Valves	Equipment	2	1500	3000
Tray driving motors	Equipment	2	1000	2000
Humidity Sensor	Equipment	2	2500	5000
Hardware	Miscellaneous	1	8000	8000