An ultrasonic flow meter device (100, 200), comprising: a piping arrangement (101, 201) comprising a tubular body (102, 202) extending along a longitudinal axis from a first end (103, 203) to a second end (104, 204) and including a measurement section (105, 205) disposed intermediate the first end (103, 203) and the second end (104, 204), the tubular body (102, 202) defining a fluid passage (108, 208) extending along the longitudinal axis through the tubular body (102, 202) from the first end (103, 203) to the second end (104, 204); at least two ultrasonic transducers (120a, 120b, 220a, 220b) disposed on opposing sides (111, 112, 211, 212) of the tubular body (102, 202) and spaced apart along the longitudinal axis; and at least two reflective elements (130a, 130b, 230a, 230b) disposed on the opposing sides (111, 112, 211, 212) of the tubular body (102, 202) and spaced apart along the longitudinal axis, wherein the at least two ultrasonic transducers (120a, 120b, 220a, 220b) are configured to generate and/or receive an ultrasonic sound wave and the at least two reflective elements (130a, 130b, 230a, 230b) are configured to direct the ultrasonic sound wave through the fluid passage (108, 208) in the measurement section (105, 205) of the tubular body (102, 202) from one of the at least two ultrasonic transducers (120a, 120b, 220a, 220b) to another of the at least two ultrasonic transducers (120a, 120b, 220a, 220b) in a travel path (150, 250) that is substantially Z-shaped, wherein the fluid passage (108, 208) includes an inlet (109, 209) defined at the first end (103, 203) of the tubular body (102, 202) and an outlet (110, 210) defined at the second end (104, 204) of the tubular body (102, 202), the fluid passage (108, 208) having a first width at the inlet (109, 209) and the outlet (110, 210) and a second width in the measurement section (105, 205) of the tubular body (102, 202), wherein the first width of the fluid passage (108, 208) is larger than the second width, and wherein the fluid passage (108, 208) in the measurement section (105, 205) has an oblong circular shape, configured to create an elliptical flow of liquid through the measurement section (105, 205), characterized in that a cross-sectional area of the fluid passage (108, 208) at the inlet (109, 209) and the outlet (110, 210) is the same as a cross-sectional area of the fluid passage (108, 208) in the measurement section (105, 205), each of the at least two reflective elements (130a, 130b, 230a, 230b) is disposed on a respective bracket (131, 231) inserted in the fluid passage (108, 208), the brackets (131, 231) being configured to support the reflective elements (130a, 130b, 230a, 230b) such that the reflective elements (130a, 130b, 230a, 230b) block a minimal area of the fluid passage (108, 208). a piping arrangement (101, 201) comprising a tubular body (102, 202) extending along a longitudinal axis from a first end (103, 203) to a second end (104, 204) and including a measurement section (105, 205) disposed intermediate the first end (103, 203) and the second end (104, 204), the tubular body (102, 202) defining a fluid passage (108, 208) extending along the longitudinal axis through the tubular body (102, 202) from the first end (103, 203) to the second end (104, 204); at least two ultrasonic transducers (120a, 120b, 220a, 220b) disposed on opposing sides (111, 112, 211, 212) of the tubular body (102, 202) and spaced apart along the longitudinal axis; and at least two reflective elements (130a, 130b, 230a, 230b) disposed on the opposing sides (111, 112, 211, 212) of the tubular body (102, 202) and spaced apart along the longitudinal axis, wherein the at least two ultrasonic transducers (120a, 120b, 220a, 220b) are configured to generate and/or receive an ultrasonic sound wave and the at least two reflective elements (130a, 130b, 230a, 230b) are configured to direct the ultrasonic sound wave through the fluid passage (108, 208) in the measurement section (105, 205) of the tubular body (102, 202) from one of the at least two ultrasonic transducers (120a, 120b, 220a, 220b) to another of the at least two ultrasonic transducers (120a, 120b, 220a, 220b) in a travel path (150, 250) that is substantially Z-shaped, wherein the fluid passage (108, 208) includes an inlet (109, 209) defined at the first end (103, 203) of the tubular body (102, 202) and an outlet (110, 210) defined at the second end (104, 204) of the tubular body (102, 202), the fluid passage (108, 208) having a first width at the inlet (109, 209) and the outlet (110, 210) and a second width in the measurement section (105, 205) of the tubular body (102, 202), wherein the first width of the fluid passage (108, 208) is larger than the second width, and wherein the fluid passage (108, 208) in the measurement section (105, 205) has an oblong circular shape, configured to create an elliptical flow of liquid through the measurement section (105, 205), characterized in that a cross-sectional area of the fluid passage (108, 208) at the inlet (109, 209) and the outlet (110, 210) is the same as a cross-sectional area of the fluid passage (108, 208) in the measurement section (105, 205), each of the at least two reflective elements (130a, 130b, 230a, 230b) is disposed on a respective bracket (131, 231) inserted in the fluid passage (108, 208), the brackets (131, 231) being configured to support the reflective elements (130a, 130b, 230a, 230b) such that the reflective elements (130a, 130b, 230a, 230b) block a minimal area of the fluid passage (108, 208).