Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Reexamination Certificate
2002-01-07
2004-05-25
Barlow, John (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
Reexamination Certificate
active
06741942
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a free-flow fluid measurement meter for metering the flow of liquids, particularly milk, and a method for employing such an apparatus.
BACKGROUND OF THE INVENTION
Free-flow milk meters are known. They provide a valuable tool in monitoring milk production on an individual animal basis. One of their benefits is that milk volume or mass can be measured without batching the milk. Thus, a reading of the milk produced by a cow can be obtained while the milk is being delivered to storage vats directly from the cow.
The measurement of milk produced by animals is a difficult task because the milk being measured is actually a two-phase, gas-liquid system. In modern milking installations, the milk coming from the cow is pumped in a pulsed fashion, permitting the entry of often large amounts of air. Physical properties used to measure milk flow rate, volume, or mass are generally dependent on the percentages of milk and air present. Milk that contains substantial amounts of air, often leads to spurious readings of the parameters used to track the volume, mass, or flow rate of the milk.
In the case of milk flow meters, the formation of froth or foam on top of the air-laden milk can never by avoided completely. In order to minimize the formation of froth or foam and diminish turbulence, the cyclical flow fluctuation caused by the pulsations of the required vacuum apparatus are typically smoothed as much as possible before the milk flows through the measuring chamber of the meter. Both the milk froth or foam and the turbulence cause measuring difficulties by impairing the signal of the sensor used in the milk meter. In addition, most milk meters are subject to milk spray when the milk enters the meter. As a result, during and after use, at least some, if not all, of the meter will be covered by a residue of sprayed milk. An unacceptable film of this milk residue, formed after each milking, must be removed by an adequate cleaning operation. Cleaning is generally effected after milking all members of a herd with the purpose of preventing the growth of microbial organisms.
Typical, free-flow milk meters which can be used to measure the flow rate of milk being delivered and/or the volume and/or mass being measured, without the use of batch measurements are described in U.S, Pat. Nos. 4,452,176, 4,476,719, and 4,346,596, to Hoeflmayer et al., Millar et al. and Diament et al., respectively. All of these meters have complex structures with recessed, partially hidden, surfaces, which make cleaning these meters relatively difficult. Moreover, since they all use direct measurement of a parameter indicative of milk level in the meter, they are dependent on the amount of air present in the milk.
The problems related to milk meters are also encountered in other industrial and laboratory settings. Whenever there is a two-phase, gas-liquid system, measurement of the flow rate, volume, or mass of the liquid in the system is difficult. All these applications require meters that are relatively insensitive to the amount of gas present and which permit easy cleaning.
In what is discussed herein, “flow rate” is liquid rate of flow in mass per unit time e.g. kg/min while “total mass” relates to the integration of flow rate over the measurement duration.
SUMMARY OF THE PRESENT INVENTION
The present invention relates to a liquid measuring device, which has been developed, particularly, though not solely, for use as a milk meter which measures the flow and quantity of milk obtained from individual cows in a herd.
It is an object of the present invention to provide a free-flow liquid meter, particularly one for use with milk, that has a simple construction, is cheap to manufacture, and is easy to maintain.
It is a further object of the invention to reduce the air in the liquid being measured, thereby increasing the accuracy of the measurements.
It is an object of the present invention to provide a free-flow liquid metering apparatus that is easy to clean.
It is yet another object of the present invention to provide a method for reducing the effect of entrained gases or air when measuring the flow rate of a free flowing liquid.
The present invention provides a free-flow liquid metering apparatus that consists of a block of sensors, typically electrodes, usually conductivity electrodes, in a specific configuration for precision measurement of the level of liquid in the meter. The measurement sensors are positioned in a helical configuration, a staircase configuration or an otherwise generally stepped configuration. The sensors are positioned between a separation wall containing a slot through which the liquid freely exits and a baffle. The baffle prevents liquid entering the measurement chamber from splashing the electrodes, while freeing entrained gases.
According to one aspect of the present invention, the invention provides a method of measuring flow or volume or mass of a liquid. The method includes the steps of causing the liquid being measured to flow through a slot of generally narrow width but long verticality so that a pool of liquid is maintained upstream of the slot such that the level of the liquid in the pool is a function of the flow rate of the liquid. The flow rate is indicated by measuring the level of liquid in the pool. In addition, the method requires the normalization of the parameter being measured, the parameter typically being conductivity.
According to another aspect of the invention, a baffle is taught where the baffle extends from an upper portion of the free-flow liquid meter's housing to a lower portion of the meter. The baffle thereby provides a continuous flow surface from the upper portion of the meter's housing into the lower portion of the housing, preventing splashing on the electrode by the entering liquid.
There is thus provided in accordance with the present invention an apparatus for measuring the flow rate of a liquid tending to froth. The apparatus includes a flow-through housing having an interior and a floor. The housing further includes a separation wall which divides the housing into a measurement chamber and a discharge chamber. The separation wall has a slot in it which allows the liquid to freely flow from the measurement chamber into the discharge chamber. The housing has an inlet communicating with the measurement chamber through which liquid enters the housing. The housing also has an outlet communicating with the discharge chamber through which liquid exits the housing. The apparatus also includes electrical sensor apparatus for sensing the level of the liquid in the measurement chamber. The electrical sensor apparatus includes a reference sensor and a common sensor both positioned proximate to the floor, and a plurality of measurement sensors, These sensors are positioned within the measurement chamber. The measurement sensors are spaced apart in a generally vertical stepped continuum stretching from the floor of the housing to a height substantially equal to the top of the separation wall at predetermined measurement intervals. The apparatus also includes a processing apparatus for evaluating a flow rate, according to a preprogrammed process, based on readings received from the sensors.
Further, in accordance with another embodiment of the measuring apparatus, the processing apparatus includes a microprocessor which receives readings from sensors, and converts the readings to a flow rate by using a look-up table stored in a memory or storage unit. The look-up table correlates the readings to a flow rate. In other embodiments of the measuring apparatus, the processing apparatus includes a microprocessor which receives readings from sensors, and converts the readings to a flow rate by using a function which is stored in a memory or storage unit. The function correlates the readings to a flow rate.
Additionally, in accordance with a preferred embodiment of the measuring apparatus, during use of the processing apparatus, the common and reference sensors measure an electrical parameter of the liquid proxi
Andrei Rony
Herman Zvi
Kapitulskiy Alexander
Pinsky Niv
Barlow John
Lau Tung
Lilling & Lilling P.C.
S.A.E. Afikim
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