US Patent 10190896 Ultrasonic flow sensor and method of attaching the same

To position first and second sensor units easily at adequate positions simply by an operation for fixing a fitting to given piping. A first fitting for a first sensor unit and a second fitting for a second sensor unit are provided. The first and second fittings include a pair of arm portions configured to regulate relative position between the first sensor unit and the second sensor unit in a circumferential direction of the piping, and a guide portion formed at least on the arm portions, and configured to guide relative positioning between the first fitting and the second fitting in an axial direction of the piping according to a diameter of the piping.