Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing liquid or solid sample
Reexamination Certificate
1999-03-29
2002-11-12
Alexander, Lyle A. (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing liquid or solid sample
C422S082010, C436S023000, C436S150000, C119S014010, C119S014140, C119S014170
Reexamination Certificate
active
06479017
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention refers to a device for measuring an electrical parameter in the milk during the milking of an animal, comprising a transportation member, arranged to transport the milk from a teat of said animal to a milk collecting member of a milking machine and forming a passage for the milk to be transported, and at least two electrodes provided to be in contact with the milk flowing through the passage and connected to an evaluation unit.
2. Description of the Prior Art
It is known that the electrical conductivity of the milk is changed when the milk is infected because of mastitis or milk fever, for instance. In particular, the number of ions increases in these cases, resulting in an increase of the conductivity of the milk . By measuring the conductivity of the milk, it is thus possible to determine whether the milk is infected. An acute inflammation of an udder gives a relatively great change of the conductivity of the milk and is thus relatively easily detected by means of such a measurement. Theoretically, it is however a precondition that such a measurement of the conductivity is performed on a known volume and in practice this means that in order to obtain comparable conductivity values a certain quantity of milk has to be located between the measurement electrodes. If this quantity is not determined in a secure manner or is not equal at each milking occasion, merely a value of the conductance of the actual unknown milk quantity is obtained. In particular, in connection with latent inflammations of the udder, it is important that the measurement is performed on a certain quantity of milk since such a latent inflammation merely results in a small change of the conductivity of the milk.
EP-A-397 274 discloses a mastitis detector having electrodes for measuring the conductivity of the milk from a teat. The detector is provided in a milk conduit and comprises a cup shaped chamber which is open upwardly against the direction of the milk flow. The electrodes are provided in the bottom surface of the chamber. When the milk is flowing through the milk conduit a quantity thereof will be collected in the chamber and be in contact with the electrodes. Thereby, a measurement of the conductivity of the milk may be performed. However, the detector disclosed does not guarantee a flow through the chamber but at least a part of the collected milk quantity present in the chamber remains therein irrespective of how much milk is flowing through the milk conduit. This means that also when the milk flow has ceased the detector will provide a conductivity value for the milk which still may be present in the chamber.
GB-A-2 124 877 discloses a device for indicating a milk flow through a milk conduit of a milking machine. The milk conduit is provided between a claw and a collecting member of the milking machine. The milk conduit comprises two electrodes provided one after the other in the direction of the milk flow and each consisting of an open cylinder abutting the inner wall of the milk conduit. A voltage is applied to the electrodes and thus the variations in the conductance of the milk flowing through the milk conduit is measured. The result of these measurements are utilized for interrupting the milking when the mean value of said measurements falls below a certain value. However, by means of the device disclosed it is not possible to know how much milk there is between the two electrodes and therefore no reliable value of the conductivity of the milk may be obtained.
EP-B-137 367 discloses a milking device comprising measurement equipment for detecting the milk flow from an individual teat. The value detected may be utilized for determining when the milking from this teat is to be interrupted. The measurement equipment comprises two electrodes for each milk flow to be detected. According to a first embodiment, a milk conduit for a milk flow comprises a main passage and a secondary passage in which two electrodes are provided. At the end of the secondary passage there is a small hole permitting the milk to flow from the secondary passage back into the main passage. In such a manner a flow through the secondary passage is obtained. However, the small hole is very sensitive for dirt particles or fat agglomerations, which may be present in the milk and which tend to stop up the small hole. In such a manner the flow through the secondary passage is interrupted and no proper conductivity value for the milk is obtained. According to another very simple embodiment, the milk conduit comprises a throttling, and upstream of the throttling two electrodes. By this simple device it is merely possible to determine whether milk has been collected in the area above the throttling. It is to be noted that the throttling of course has to be provided in such a manner that it permits a relatively large milk flow therethrough. According to a third embodiment, the milk is conducted from each teatcup to a claw having a main passage. In addition, for each teatcup a secondary passage is provided in the claw in such a manner that a certain quantity of the milk from a teatcup will be conducted into a respective secondary passage. The secondary passage comprises two electrodes for measuring the conductivity of the milk being present in the secondary passage. In the same way as in the first embodiment, there is a small hole at the end of the secondary passage connecting the secondary passage to the main passage. In such a manner, a flow through the secondary passage is ensured. Also in this case the risk of stopping up the hole is significant.
U.S. Pat. No. 4,325,028 discloses a device for measuring the conductivity of the milk from each individual teat in a milk conduit between the teatcup and the claw. The measurement equipment comprises a receiving device, provided in each such milk conduit and having electrodes located therein, and an electronic evaluation device. The construction of the receiving devices are not described more closely. The aim of the device disclosed is to enable the determination whether the conductivity value of the milk from an individual teat is abnormal and thus whether any udder part is inflamed.
WO 83/03305 discloses an electrical conductivity device for detecting mastitis in the milk from a cow by measuring the conductivity of the milk. The device is intended in the first place for manual use although it is mentioned that it may be provided near a claw of a milking machine. The device is adapted to collect a minor secondary milk flow of the main milk flow and conduct this secondary milk flow through a testing passage in the form of a flexible tubing comprising two electrodes. The flexible tubing is relatively thin and there is a risk that dirt particles or fat agglomerations may stop up the milk flow therethrough.
WO 95/22888 discloses a claw for a milking machine having means for measuring the complex impedance, such as the electrical conductance and/or the capacitance, of the milk in order to detect mastitis. The claw comprises four inlet members and four chambers provided beneath a respective inlet member for collecting a part of the milk flowing through the inlet member into the claw. In the bottom wall of the chamber there is a small opening permitting the milk collected therein to slowly drain away. Also this known device provides a risk that dirt particles and fat agglomerations stop up the milk flow through the small opening.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy the problems mentioned above and provide an improved device for measuring an electrical parameter of the milk. In particular, the invention aims at a device permitting the measurement of small milk flows and simultaneously ensuring a continuous milk flow through the measurement location.
This object is obtained by the device initially defined and characterized in that the transportation member comprises a wall member provided in the passage and forming a groove being open towards the passage, said electrodes being provide
Alexander Lyle A.
DeLaval International AB
Williams LLP Hovey
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