Foods and beverages: apparatus – Mechanical – fluid or heat treatment of dairy food – With temperature or atmosphere modification
Reexamination Certificate
2000-03-21
2001-02-20
Simone, Timothy F. (Department: 1761)
Foods and beverages: apparatus
Mechanical, fluid or heat treatment of dairy food
With temperature or atmosphere modification
C099S452000, C099S453000, C099S470000, C099S483000
Reexamination Certificate
active
06189440
ABSTRACT:
BACKGROUND OF THE INVENTION
Dairy farmers feed calves colostrum, transitional milk, milk and/or formula for the first six to twelve weeks of a calf's life. Throughout this article, “milk” will refer to all milk except formula. Cow's milk has economic value and therefore, farmers that feed milk typically use milk that does not meet the quality requirement for human consumption. This milk is referred to as “non-saleable” or waste milk. Waste milk does not meet the quality standards because it comes from a cow that either has a disease or is being treated with antibiotics to rid the cow of a disease. On average, 2% of a dairy herd carries a disease that make the milk produced by the diseased cows non-saleable. Pasteurization is one method of improving the quality of waste milk by reducing the potential for disease transmission to the calf.
Formula is used as a food source for calves because it is free from disease, easy to prepare and costs less to feed than saleable milk. Unfortunately, it is still expensive and does not provide the same level of nutrition as cow's milk.
A pregnant cow will not give milk for the last 45-60 days of pregnancy. The first milk produced by the cow after giving birth is colostrum. Colostrum contains antibodies and other important nutritional components critical for the newborn calf. The next couple of milkings after colostrum are referred to as transitional milk. Transitional milk has fewer antibodies and less fat than colostrum.
University research indicates that if colostrum is pasteurized before it is fed to the calf, the calf will weigh more and therefore, is worth more when it goes to market. The antibodies and proteins in colostrum and transitional milk are very sensitive to heat. Colostrum can be pasteurized but the temperature and heating duration must be controlled to limit the damage to proteins and antibodies. The temperature and time that has been demonstrated to be most effective is 161° F. for 15 seconds.
This temperature and time relationship is common in the pasteurizing industry and is referred to as High Temperature Short Time (HTST) pasteurization. Nearly all pasteurized milk consumed by humans today is pasteurized using HTST.
Onsite pasteurization has not been economically feasible up to now because of the complexity and therefore, cost of pasteurizing systems. Pasteurizing systems that were originally designed for pasteurizing products other than cow's milk are being sold to dairy farmers as pasteurizers for milk destined for calves. These pasteurizers are very expensive and have not been designed with the dairy farmer in mind.
Dairy farmers are very busy. A pasteurizer built for today's dairy farmer needs to perform quickly, be easy-to-use, cost effective and require low maintenance. Other systems use water heat or large metal plates for heat exchange. These systems heat up slowly, and therefore, increase the amount of time required to process a batch of milk. Other systems also require multiple operator steps and depend on additional accessories, like tanks, for effective operation.
Consequently, an affordable, convenient way to pasteurize the milk that dairy farmers feed their calves is needed. Such a pasteurizer can give the dairy farmer a means for significant economic benefit through decreased dependence on formula and increased calf health and market value.
SUMMARY OF THE INVENTION
The pasteurizer of the present invention is self-contained and pasteurizes fluids such as milk in a continuous manner. The pasteurizer may be a stationary unit but is preferably mounted upon a mobile cart or the like. In its simplest form, this pasteurizer comprises a first, raw milk tank and a second, pasteurized milk tank. These tanks are fluidically connected by a pasteurization conduit that has a first section where the milk is heated to its pasteurization temperature, a second section which holds the temperature of the milk substantially at its pasteurization temperature for a specified length of time and a third section that acts to cool the milk down to a more useable temperature. A single pump is connected inline with the pasteurization conduit immediately adjacent the raw milk tank and pumps fluids from the first tank to the second tank through the pasteurization conduit at a substantially constant flow rate.
At least one heating element for heating the fluids flowing through the heating section is arranged substantially parallel to the heating section of the pasteurization conduit. The heating elements are preferably retained in a heat transfer structure that has a first channel constructed and arranged to receive therein the heating section of the pasteurization conduit and a second channel that is constructed and arranged to receive therein the heating element. The heat conducting structure positively locates the heating element with regard to the heating section of the pasteurization conduit and acts to thermodynamically couple the heating element to the heating section of the pasteurization conduit.
The temperature hold section of the pasteurization conduit is situated such that the fluids flowing therethrough are subject to substantially no heating or cooling. In order to ensure that the fluids flowing through the temperature hold section are held at their pasteurization for the required length of time, the length of the temperature hold section is based on the flow rate of the fluids flowing therethrough.
In order to conserve space, the heating and temperature hold sections of the pasteurization conduit are preferably arranged circumjacent to the raw milk tank.
The cooling section of the pasteurization conduit is passed through a cooling mechanism such that the fluid flowing therethrough is cooled below its predetermined temperature before being deposited in the second tank. One suitable cooling mechanism is a water bath that is maintained at a relatively lower temperature than the predetermined temperature of the fluids flowing from the temperature hold section to the cooling section.
In order to ensure that the fluids being pumped through the pasteurization conduit reach the desired pasteurization temperature, a diversion valve is connected in line with the pasteurization conduit between the heating section and the temperature hold section. The diversion valve has a first position in which fluids flowing through the heating section pass through the diversion valve and into the temperature hold section. The diversion valve also has a second position in which fluids flowing through the heating section pass through the diversion valve and into a recirculating conduit that directs the fluids back into the first tank. A control means for actuates the diversion valve between its first and second positions based on the temperature of the fluids exiting the heating section of the pasteurization conduit. When the fluids are below the desired temperature, the control means actuates the diversion valve to recirculate the fluids back into the first tank. Fluids that have reached the desired pasteurization temperature are allowed to pass from the heating section, through the diversion valve, and into the temperature hold section of the pasteurization conduit.
In the preferred embodiment of the present invention, the heating section of the pasteurization conduit brings the fluid flowing therethrough to the pasteurization temperature of substantially 161° F. and the temperature hold section of the pasteurization conduit maintains the fluid at its pasteurization temperature of substantially 161° F. for substantially 15 seconds.
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Moore & Hansen
Simone Timothy F.
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