Abstract: A flow meter using digital signals constructed in a small size and outputting an electric signal of a position of a float in a tapered tube with high accuracy is provided. A first reflecting means 6 has a ray 20 entered from the entering means 5 and reflected, and a second reflecting means 7 reflecting the ray 20 reflected from the first reflecting means 6 toward the first reflecting means 6 at least once. An emitting means 8 has the ray 20 entered and emits it, and an image sensor 9 has the ray 20 from the emitting means 8 entered and outputs an image of the float 3 in the tapered tube 1, while a control portion executes input processing of an image and outputs an electric signal S1 indicating the flow rate of a fluid 2 by detecting the position of the float 3.

Abstract: A flow meter using digital signals constructed in a small size and outputting an electric signal of a position of a float in a tapered tube with high accuracy is provided. A first reflecting means 6 has a ray 20 entered from the entering means 5 and reflected, and a second reflecting means 7 reflecting the ray 20 reflected from the first reflecting means 6 toward the first reflecting means 6 at least once. An emitting means 8 has the ray 20 entered and emits it, and an image sensor 9 has the ray 20 from the emitting means 8 entered and outputs an image of the float 3 in the tapered tube 1, while a control portion executes input processing of an image and outputs an electric signal S1 indicating the flow rate of a fluid 2 by detecting the position of the float 3.

Abstract: A flow meter outputs an electric signal of a position a float within a taper-shaped tube precisely. A taper-shaped tube is made of an approximately transparent material, is mounted approximately vertically, and circulates a fluid such as water or the like, and a float is arranged within the taper-shaped tube so as to displace in a vertical direction in correspondence to a flow rate of the fluid. An LED irradiates a light ray to the taper-shaped tube and the float, makes the light ray to transmit through the taper-shaped tube, and generates a transmitted light ray. The image sensor outputs a digital image of the float within the taper-shaped tube, and a control portion 11 executes an input process of the digital signal detects the position of the float, and outputs an electric signal showing a flow rate of the fluid.