Rotary blancher for processing food product

Abstract

A method and rotary blancher for processing food product using a heat transfer medium and directed flows of a fluid that can comprise a liquid, a gas, a vapor or a combination thereof. The directed flows can be discharged from orifices or banks of orifices that are distributed around the food products in the blancher. The flows are discharged at a high flow rate, a high pressure, or a combination of both. Where a liquid is discharged, it preferably is discharged at a flow rate of at least 20 gpm and at least 30 psi. Where a gas is discharged, it is discharged at a flow rate of at least 60 CFM at a pressure of at least 2 psi or at a flow rate of at least 10 CFM at a pressure of at least 80 psi. If desired, discharged fluid can be recirculated to save energy. To help increase agitation and help break up clumps of food products in the blancher, direct-contact mechanical agitation devices, such as baffles, can be used. Such a blancher and method can be used to process food product by blanching, cooking and pasteurizing, is suited for processing relatively heavy food products having a density of at least 55 lbs / ft3 using discharged liquid and gas, and is suited for processing food products having a lesser density using only discharged gas.

Description

FIELD OF THE INVENTIONThe present invention relates to rotary blanchers and more particularly to a method and rotary blancher for processing food products that comprises introducing a fluid into the heat transfer medium in the blancher to more efficiently and more uniformly heat the food products in the blancher and which can be used to blanch, cook or pasteurize the food products.BACKGROUND OF THE INVENTIONA wide variety of food products, such as pasta, beans, corn, peas, and other vegetables and fruit, are processed every day around the world by blanching or heating. For many years, the basic rotary blancher consisted of an elongate cylindrical perforate drum received in a tank filled with heated water. Food products are continuously introduced through an inlet in one end of the drum and heated by the water in the tank. During operation, flights of a helical auger in the drum rotate and urge the food products from the drum inlet toward a drum outlet.However, food products tend to ...

AI Technical Summary

Benefits of technology

The patent describes a rotary blender and method for processing food products by heat transfer. The blender includes a housing with an inlet and an outlet, a rotary food product transport mechanism, and a heat transfer medium. The heat transfer medium can be a liquid or gas, and can be heated to blanch, cook, or pasteurize the food products. The blender has a plurality of orifices that discharge fluid into the heat transfer medium, which helps break up food products and prevent them from clumping together. The fluid can be discharged at high flow rates and pressures. The patent also describes a method for processing food products using the rotary blender.

Problems solved by technology

However, food products tend to clump together as the drum rotates resulting in poor heat transfer and uneven heating, especially for those food products in the middle of the clump.

It is believed that greater pressures and flow rates of directed water flows have not been tried before because the lower pressures and flow rates previously tried did not increase efficiency so dramatically as to predict a correspondingly greater efficiency increase.

Moreover, the cost of bigger and more powerful pumps and other equipment needed to deliver greater flow rates, particularly at higher pressures, was thought to be so cost prohibitive that any possible performance advantage was believed not to be worth it.

It has always been very difficult for rotary blanchers to process food products that are relatively heavy, typically having a density greater than 55 pounds per cubic foot (lbs / ft3).

While baffles have been used to help turn over and agitate food products during operation, heavier food products tend to clump together on the bottom and along the side of the rotating drum where the drum leaves the water.

This is believed to be caused, at least in part, by the increased weight of the food products causing them to sink and by the increased friction between the food products and the rotating drum.

Other experiments have shown that these lower turbulence (i.e. lower volume and pressure) flows of air and water used in the past, even if the blancher is equipped with agitating baffles, will not break up and agitate heavy food products enough to achieve the desired level of heat transfer needed to make blanching of heavy food products commercially viable.

Pasta, however, is relatively fragile and must be handled much more carefully during blanching than most other types of food products, which has limited attempts in the past to increase heat transfer.

As a result, throughput for a 72-inch diameter blancher has been heretofore limited to about 3500 pounds of pasta per hour, making production undesirably slow.

Thus, there has been a move to not only heat the food products until they are cooked, but to pasteurize the food products which takes longer, requires more heat, and thus is more costly.

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