	US 7,584,065 B2
	Doppler ultrasonic flowmeter, and processor and method thereof with quantization error correction
Kazuyuki Yamada, Tokyo (Japan); Yoshinori Ohmuro, Tokyo (Japan); Noritomo Hirayama, Tokyo (Japan); and Masami Kishiro, Tokyo (Japan)
Assigned to Fuji Electric Systems Co., Ltd., Tokyo (Japan)
Filed on Feb. 25, 2005, as Appl. No. 11/66,730.
Claims priority of application No. PA 2004-054264 (JP), filed on Feb. 27, 2004.
Prior Publication US 2005/0209793 A1, Sep. 22, 2005
Int. Cl. G01F 1/00 (2006.01)

U.S. Cl. 702—54 [73/861.25]

7 Claims

1. A Doppler ultrasonic flowmeter for measuring, using an ultrasonic Doppler shift, a flow rate of fluid flowing inside a conduit, comprising:

ultrasonic wave transmission/reception means for transmitting to the fluid an ultrasonic pulse with an arbitrary pulse repetition frequency, and for receiving a resulting ultrasonic echo to extract a Doppler shift component through a predetermined process;

flow velocity distribution calculation means for calculating a flow velocity distribution of the fluid based on the Doppler shift component extracted by the ultrasonic wave transmission/reception means; and

flow rate calculation means for calculating a flow rate of the fluid based on the calculated flow velocity distribution of a predetermined integration range and a quantization error occurring to a spatial resolution

wherein the flow rate calculation means calculates the flow rate (Q) based on the following equation:

where

is a flow rate coefficient of a starting channel,

(r_i·Δr_i)·v_iis a flow rate conversion factor,

is a flow rate coefficient of an end channel, and

where v is the flow velocity of the respective channel, r is the distance from the center of the conduit to the center of the respective channel, Δr is the width of the respective channel.