Electrostatic transducer for length measurement system

An electrostatic transducer adapted for use in a length measurement gauge measuring lengths of elongated material moving along a measurement path, said transducer comprising:

• a metallic tunnel radially surrounding a predetermined axial length of said measurement path;
• said tunnel having a separable top portion which, when opened, permits unobstructed access to the measurement path;
• a corona discharge electrode mounted within said tunnel;
• and
• a charge sensing electrode mounted within said tunnel at a predetermined axial distance downstream from said corona discharge electrodes.

An electrostatic transducer adapted for use with a mark/sense length measurement gauge measuring the length of material moving along a measurement path, said transducer comprising:

• a pointed corona discharge electrode disposed a substantially constant distance out of contact with the path of relatively moving material to be measured;
• a reference electrode disposed downstream of said corona discharge electrode,
• said reference electrode substantially surrounding the intended path of moving material and having an aperture formed therein;
• and
• a charge sensing electrode also substantially surrounding the intended path of moving material and disposed within said aperture at a predetermined distance from said corona discharge electrode.

An electrostatic transducer adapted for use with a mark/sense length measurement gauge measuring the length of material moving along a measurement path, said transducer comprising:

• a pointed corona discharge electrode disposed a substantially constant distance out of contact with the path of relatively moving material to be measured;
• a reference electrode disposed downstream of said corona discharge electrode,
• said reference electrode having an aperture formed therein;
• a charge sensing electrode disposed within said aperture at a predetermined distance from said corona discharge electrode
• said electrodes substantially surrounding the path of relatively moving material to be measured;
• and
• an elongated tunnel member housing all of said electrodes, said tunnel member having a separable top portion;
• and
• said electrodes also having a separable top portion whereby the material to be measured can be placed into the measurement path without threading an open end therealong.

An electrostatic transducer adapted for use with a mark/sense length measurement gauge measuring the length of material moving along a measurement path, said transducer comprising:

• a pointed corona discharge electrode disposed a substantially constant distance out of contact with the path of relatively moving material to be measured;
• a charge sensing electrode disposed a predetermined distance downstream of said corona discharge electrode, said charge sensing electrode substantially surrounding said measurement path;
• and
• an elongated tunnel member housing all of said electrodes, said tunnel member hoving a separable top portion;
• said sensing electrode also having a separable top portion whereby the material to be measured can be placed into the measurement path without threading an open end therealong.

An electrostatic transducer adapted for a length measurement system used to measure the length of material moving along an intended measurement path said transducer comprising:

• a corona discharge electrode disposed to be out of contact with said material;
• a reference electrode;
• and
• a charge sensing electrode disposed a predetermined distance from said corona discharge electrode and substantially surrounded by said reference electrode, both said sensing and reference electrodes also being disposed out of contact with the path of relatively moving material,
• said charge sensing and reference electrodes each being physically separable in at least one place to permit easy entry thereinto of the material to be measured.

An electrostatic transducer adapted for a length measurement system used to measure the length of material moving along an intended measurement path said transducer comprising:

• a corona discharge eletrode disposed to be out of contact with said material;
• a reference electrode;
• and
• a charge sensing electrode disposed a predetermined distance from said corona discharge electrode and substantially surrounded by said reference electrode, both said sensing and reference electrodes also being disposed out of contact with the path of relatively moving material,
• said charge sensing and reference electrodes including conductive areas laminated to a dielectric substrate.