Ferromagnetic object detection device and method for detecting tubing coupling

A ferromagnetic object detection device, comprising:

• a support tube, comprising a space penetrating therethrough in a first direction;
• a magnetic field generating device, located on an outer sidewall of the support tube and configured to generate a magnetic field;
• and
• a magnetic field detection device, comprising a first magnetic field detection element, a second magnetic field detection element and a third magnetic field detection element,
• wherein the first magnetic field detection element, the second magnetic field detection element and the third magnetic field detection element are all located on the outer sidewall of the support tube and within a range of the magnetic field generated by the magnetic field generating device;
• the first magnetic field detection element is configured to detect the magnetic field and obtain a first magnetic field signal to obtain a moving speed of a ferromagnetic object passing through the space in the first direction, the second magnetic field detection element is configured to detect the magnetic field and obtain a second magnetic field signal to obtain a size of the ferromagnetic object in a second direction perpendicular to the first direction, and the third magnetic field detection element is configured to detect the magnetic field and obtain a third magnetic field signal to obtain a position of the ferromagnetic object.