For a very thorough cleaning of Beans, Peas, and Grains for food processing, Shri Technology was invented by Vijai Gupta for his foods processing plant (JYOTI Natural Foods) in the USA. Among many shelf-stable cans and pouches, and refrigerated foods made by JYOTI are Mung Dal, Channa Dal, Punjabi Chhole and Madras Sambar, all of which use beans and all those beans have plenty of stones and other debris.
The basic concept of Shri technology is very simple and can be explained. Beans loaded into the machine may contain any or all of the following foreign materials:
- Stones, broken glass, metal parts like nails and screws
- Woody stems, pods, leaves, loose skin, plastic parts, and film
- Metal foil, insect infested beans, shriveled skin beans, bag fibers etc. is dropped into a tank of water, what happens?
The metal parts race to the tank bottom followed by stones and glass pieces. Good beans sink slowly but also get to the bottom. Floating debris such as woody stems, pods, leaves, loose skin, plastic film and fibers, and even insect infested beans float to the surface of the water. SHRI Technology utilizes these differences in the buoyancy of different particles to separate those. Air bubbles are used to help float such materials as shriveled skin beans, foil pieces, plastic bag filaments etc. which do not sink readily because of their shape or because of their overall density being very close to that of water.
The equipment, as seen to the left of the pilot plant, consists of a vertical column (product column), to the side of which away from either end, is attached a side arm turning vertical (feed column), looking like an inverted letter h. The open end of the feed column is slightly higher than that of the product column. The bottom end of the product column is closed with provision to be opened when needed. The top end of the product column is designed to discharge any flow from that column onto a separator screen. Water is introduced from the side of the product column at a point between the closed bottom end and the feed column joint. When water flow is started, water rises in both columns, but because the top end of the feed column is slightly higher, most of the flow goes out through the top of the product column, and a small fraction of the flow goes out through the top of the feed column. Air bubbles are introduced into the feed column at the lower end of the vertical section. Beans or grains with any kind of foreign impurities are dropped into the feed column from the open top where the sinkable particles (stones, glass, metal) and all the good beans sink through and into the product column. Water velocity in the product column is adjusted such that the beans coming in from the feed column get carried up the column by the flowing water, while the heavier particles (stones, glass, metal) sink to the bottom from where those are periodically removed. Floatable debris (twigs, loose skin, plastic parts etc.) float up and are discharged with the small flow of water into a screen basket, which collects the debris but allows the water to flow back into the water tank for recycling. Materials that do not sink easily (bag fibers, foil, insect infested beans or shriveled skin beans etc.) get floated up by the rising air bubbles and also get discharged into the screen basket that catches the debris while the water gets recycled. Thus, heavy debris collects at the bottom of the product column and is periodically removed from there. The floatable materials are removed from the screen basket. Good, thoroughly cleaned and washed beans and grains flow out with the overflow from the product column, are separated from water by a suitable screen and collected in vessels for processing, while the water is recycled.
Shri Technology has been used to make units as small as 50-100 g/min capacity for household use, midsize units of 200 – 1000 g/min suitable for institutional kitchen use and of course, large industrial units for food processors.
The scale up machine was rated for 5000 lb/hr, photo 6, but has been run at much higher rates with perfect performance. Nine stones recovered previously from the beans being used were painted yellow for visibility and were randomly mixed into a 1 ton batch of “Triple Cleaned” beans which were run through the machine. All nine stones were recovered and put back into a second 1 ton batch, recovered again and mixed into a third batch, processed and recovered in full count. One unpainted stone was recovered as well. A lot of loose skin, a handful of damaged beans and a piece of blue plastic were recovered in the basket collecting the floatables.
Shri Technology pilot plant (~ 600 lb/hr) in Philadelphia is made of heavy gauge glass for visibility of the operation and understanding of the technology for observers.
Manufacturers of kitchen appliances, restaurant equipment, and industrial food processing equipment are invited to license the technology for their own make machines. Licensees will be provided with full construction design and drawings, and assistance with design of their units. Custom made machines for specific capacity will be built to order, requiring about 4 months from order date.
The Shri Technology machines offer the following major advantages over the existing “destoners”:
- Complete removal of both – heavy and light impurities, Photos 4 and 5. Very clean, washed beans are produced from commercial quality stock.
- Lower priced commodity beans can be used instead of more expensive, “triple cleaned” beans, significantly reducing ingredient cost for food processors.
- Food produced has greatly reduced customer complaints about foreign debris and related liability issues.
- Almost zero yield loss. Only impurities, loose skin, and bad beans are removed.
- There are no moving parts (except a pump) and no lubrication points, making the machine maintenance free. Small floor space requirement. Photo 2. The operation is simple and fool-proof, so skilled labor is not required. Very small (for home kitchen), mid-size (for institutional use) and large machines for food processors can be built using SHRI Technology in any needed capacity.
While the concept is very simple, the actual design of a machine is more complex. The following problems can easily develop if not properly addressed in the design:
- Introduction of a large flow of water from the sides of a pipe can create a powerful vortex which can pick up the heavy particles trying to sink to the bottom like a tornado does. No vortex should be created by the incoming water.
- Water velocity is critical and must be controlled within a narrow range, as beans may settle to the bottom with the stones and metal, or stones may get carried up with the beans.
- A significant portion of the Beans and grains introduced into the feed column
for cleaning can
float out with the floating debris, resulting in yield loss.
- Air bubbles introduced to float out the floatable debris can also float out some good beans, causing yield loss. Size and volume of bubbles introduced is critical.
- The screen used to separate out the beans from carrying water has to be of a very special design so nearly all the water gets separated from the wet beans. Use of an ordinary screen allows water to bridge the space between screen wires by its surface tension and thus, letting it flow out with the beans instead of being separated for recycling. Photo 3.
A video of the glass pilot plant and one of the testing of a scale-up machine (5000+ lb/hr), while it was still in the machine shop where built, are available for viewing:
Vijai Gupta is a BHU (India) trained Chemical Engineer who received his Ph.D. from McGill University of Canada. He has invented 24 US Patented Process Technologies, all unrelated to each other, and has many more patents worldwide. He was invited this year to address the World Conference on Food Technology Innovations in Delhi on the subject of SHRI Technology. Later, he was a Golden Jubilee Visiting Fellow at the Institute of Chemical Technology, Mumbai where he lectured on “Process Problem Solving – A Methodology”. Last year, Dr. Gupta delivered the “Malviya Memorial lecture at the City University of New York on “Leadership and Creativity – a Different Perspective !”
Dr. Gupta served as an Advisor to the US Secretary of Agriculture on Technical Issues, 2005-2009 and currently sits on the Emerging Technologies Committee of the Grocery Manufacturer’s Association of the United States.
Vijai and his wife Jyoti, a US Registered Dietitian with an MS in Nutrition from the Texas Medical Center, reside in Philadelphia. Together, they have built and currently operate a modern food processing plant which is the mother of the invention of Shri Technology. The making of Madras Sambar at Jyoti Foods was recently filmed by the Food Network and includes a short segment of Toor Dal being run through Shri Machine. This short video can be seen here: