Sampling and measuring device with calibrating piston

A method of obtaining calibrated measurements of a physical characteristic of a product in a container, comprising the steps of:

• selecting a calibration material having at least one physical characteristic that provides an expected sensor output;
• placing a sampling tube under an aperture at the bottom of said container, at least part of said sampling tube being within the sensory area of a sensor;
• moving a piston inside said sampling tube, said piston having at least a layer made from said calibration material, to a position such that said layer is within the sensory area of said sensor, wherein said layer forms an integral body with the rest of said piston and whereby no piston structure is positioned between the side surface of the layer and sampling tube;
• sensing said layer, thereby obtaining a signal representing a measured sensor output of said layer;
• comparing the measured sensor output of said layer to said expected sensor output;
• determining a calibration factor, using the results of said comparing step;
• moving said piston to a position such that said sampling tube receives a sample of said product via said aperture;
• sensing said sample, thereby obtaining a signal representing a measured sensor output of said sample;
• and
• adjusting said measured sensor output of said sample, using said calibration factor.

A method of calibrating a sampler that measures a physical property of a product in a container, comprising the steps of:

• selecting a calibration material having physical characteristics that provide an expected sensor output;
• placing a sampling tube under an aperture at the bottom of said container, at least part of said sampling tube being within the sensory area of a sensor;
• moving a piston inside said sampling tube, said piston having at least a layer made from said calibration material, to a position such that said layer is within the sensory area of said sensor, wherein said layer forms an integral body with the rest of said piston and whereby no piston structure is positioned between the side surface of the layer and sampling tube;
• sensing said layer, thereby obtaining a signal representing a measured sensor output of said layer;
• comparing the measured sensor output of said layer to said expected sensor value;
• and
• adjusting the output of said sensor, based on the results of said comparing step.

A sampling and measuring system for obtaining a sample of a product from a container having a sampling aperture, and for measuring a physical property of the sample, comprising:

• a sampling device having a sampling tube for attachment to said container, such that it receives said sample via said sampling aperture, said sampling tube having a port end in communication with said sampling aperture and having a stopper end opposite said port end;
• a piston moveable within said sampling tube, having a substantially sealed relationship with the inner walls of said sampling tube such that said piston may be moved upwardly within said sampling tube to provide an upward force at the bottom surface of said sample to return said sample to said container via said sampling aperture, said piston having at least a layer of calibrating material that is an integral part of said piston;
• and a sensor for sensing said physical characteristic of said sample while said sample is within said sample tube;
• wherein said layer has at least one physical characteristic that provides a known expected output of said sensor and whereby no piston structure is positioned between the side surface of the layer and sampling tube;
• a calibration mode selector for initiating a calibration mode of said sampler;
• a piston control processor in communication with said calibration mode selector, for placing said piston in a calibration position, such that said calibration layer is within the sensory area of said sensor;
• and
• a calibrator in communication with said calibration mode selector, for receiving a measured signal from said sensor while said piston is in said calibration position and for comparing said measured signal with a reference signal.