Oval Corporation

Tamura Electric Works, Ltd.

Kazuhide Kobayashi

Shingo Gomi

Kimihiro Ichinose

Osamu Futagawa

Seiji Kobayashi

Takashi Endo

Takehiko Ishii

Hirokazu Kitami

Osamu Kai

Kenichi Matsuoka

A double-tube type Coriolis flow meter is provided for measuring mass flow. The flow meter includes a straight flow tube ( ) through which the fluid being measured flows, a hollow outer tube ( ) secured at both ends thereof to act as a counterbalance, a drive unit ( ), and a pair of sensors. The flow tube ( ) is caused to vibrate by the drive unit ( ) so that the mass flow of the fluid is measured by detecting a phase difference proportional to Coriolis force acting on the flow tube ( ) by the sensors. Sheet members (coupling plates ) secure the flow tube ( ) to both ends of the outer tube ( ) and integrally form the coupling plate ( ) with tube-assembly supporting leaf springs ( ) in the double-tube type Coriolis flow meter. By connecting the flow tube to the outer tube via the sheet members in this manner, stresses produced between the tubes are absorbed and a uniform temperature distribution is maintained in the outer tube and manufacturing costs are reduced.

Straight double-tube type coriolis flow meter

A resonantly drivable straight tube type Coriolis flowmeter which is capable of correcting instrumental errors caused by a change in density and temperature of measurable fluid. A coaxial double tube body that is composed of an inner tube wherein fluid to be measured flows and an outer tube with a balance weight attached thereto for equalizing natural frequencies of the inner and outer tubes is driven at a resonant frequency having a constant amplitude. A change of fluid density causes a change of amplitude ratio of the inner tube and the outer tube, resulting in shifting of an instrumental error. At this time, a resonant frequency detecting circuit detects a resonant frequency without detecting the amplitude ratio. An instrumental error detecting circuit stores a relation between resonant frequencies and fluid densities and a relation between fluid densities and instrument errors and conducts correction of an instrumental error according to the detected resonant frequency. An instrumental error caused by thermal deformation of the inner tube and the outer tube which are different from each other in material and shape can be also corrected by using similar correcting means.

Error correcting Coriolis flowmeter

A power source control circuit for a telephone set, includes a power source switch, a detecting circuit, a power hold circuit, and a control circuit. The power source switch supplies an external power to the telephone set. The detecting circuit detects an off-hook operation of the telephone set or an incoming signal arriving at a line. The power hold circuit holds the power source switch in an ON state for a predetermined time period on the basis of an output from the detecting circuit. The control circuit is activated by supply of the external power and transmits an extension signal for extending the ON state of the power source switch within the predetermine time period.

Power source control apparatus for telephone set

Growing community of inventors

Tokyo, Japan

Kazuhide Kobayashi