Oval Corporation

Hirokazu Kitami

Hideki Shimada

Yuichi Nakao

Norio Sukemura

Seiji Kobayashi

Takashi Endo

Kenichi Matsuoka

Shingo Gomi

Toshihiro Abe

Toshiyuki Satoh

Kimihiro Ichinose

Kazuhide Kobayashi

Shunji Saitoh

Osamu Futagawa

Hiraku Kawaoto

A signal processing method for a Coriolis flowmeter including: performing frequency conversion to combine an oscillation frequency to each of two flow rate signals obtained by A/D conversion on input signals of the phase difference and/or the vibration frequency proportional to the Coriolis force acting on the at least one flow tube; measuring a frequency of a composite waveform associated with at least one of the vibration detection sensors; transmitting a control signal based on the measured frequency; controlling so that a sum frequency component or a difference frequency component of a composite component of a composite frequency signal is constant; and measuring phases from a sum signal or a difference signal of each of controlled converted composite frequencies, to thereby obtain a phase difference signal component.

Signal processing method, signal processing apparatus, and Coriolis flowmeter

A signal processing method, a signal processing apparatus, and a Coriolis flowmeter are capable of always performing measurement with constant precision and performing phase measurement with high filtering performance and a small amount of computation even when a temperature of a fluid to be measured changes, air bubbles are mixed into the fluid to be measured, or the fluid to be measured rapidly changes from a gas to a liquid. The Coriolis flowmeter detects at least one of a phase difference and a vibration frequency proportional to a Coriolis force acting on at least one flow tube or a pair of flow tubes.

A signal processing method for a Coriolis flowmeter, the signal processing method including: measuring a frequency of a first digital signal obtained by converting a first input signal from one of a pair of vibration detection sensors into the first digital signal; transmitting a modulatable frequency signal based on the measured frequency of the first digital signal; performing frequency conversion to add or subtract the frequency of the modulatable frequency signal to or from the frequency of the first digital signal; performing frequency conversion to add or subtract the frequency of the modulatable frequency signal to or from the frequency of a second digital signal obtained by converting a second input signal from the other one of the pair of vibration detection sensors into the second digital signal; and measuring a phase difference between (i) the frequency converted first digital signal and (ii) the frequency converted second digital signal.

A signal processing method for a Coriolis flowmeter including: performing frequency conversion of a first digital signal, the frequency conversion performed on the first digital signal modulating the frequency of the first digital signal so that the frequency of the first digital signal after the frequency conversion is 1/Nth of the frequency of the first digital signal before the frequency conversion, where N is an integer; performing frequency conversion of a second digital signal, the frequency conversion performed on the second digital signal modulating the frequency of the second digital signal so that the frequency of the second digital signal after the frequency conversion is 1/Nth of the frequency of the second digital signal before the frequency conversion; and measuring a phase difference between (i) the frequency converted first digital signal and (ii) the frequency converted second digital signal.

Signal processing method, signal processing apparatus, and coriolis flowmeter

A hierarchical structure display device according to the present invention includes operation condition output means for outputting operation condition information for a switch operation condition of a first switch or a second switch to cause an operator to recognize the operation. condition information, and screen transition means for operating only when a detected switch operation of the first switch or the second switch satisfies the switch operation condition related to the operation condition information output from the operation condition output means to carry out a screen transition of a display screen. Further, the operation condition information is a display image which is displayed within the display screen and repeatedly inverted at predetermined timing during a switch operation, and a necessary number of times of inversion for the switch operation condition is displayed as the display image.

Hierarchical structure display

A processing method for an operation system which performs operation processing in accordance with a detection amount detected by detection means and pulse output processing in which an operation result from the operation processing is transmitted as a pulse output, including: controlling transmission of the pulse output performed in the pulse output processing to make the transmission of the pulse output asynchronous with a timing of an end of the operation processing; and transmitting, by repeating the controlling, a pulse train having time-series continuity.

Processing method in operation system, flow rate converter, and coriolis flow meter

In order to extract a part of a three-phase flow from a pipe line, a pair of communication pipes, which are connected to upstream and downstream sides of an orifice provided in the pipe line, and a gas-liquid extraction tank are used. Flowing of a slag flow or the like into the pipe line causes a periodical change in a pressure difference between input and output sides of the orifice. This causes extraction of gas-liquid and discharge mainly of gas to be simultaneously effected in the pair of communication pipes and the gas-liquid extraction tank. Within the gas-liquid extraction tank, the gas-liquid is forcibly shaken horizontally, vertically, etc. for agitating, whereby gas-liquid of high liquid-phase rate remains. Then, the gas is removed from this gas-liquid of high liquid-phase rate to thereby extract mixture liquid, which is accumulated in a liquid storage tank. The mixture liquid flows from the liquid storage tank in an amount required at a Coriolis meter. As a result, high precision density measurement is performed at the Coriolis meter.

Multiphase flowmeter for measuring each phase flow rate of a three-phase flow consisting of gas and two kinds of liquid

A first inlet portion, a second inlet portion, a first outlet portion, and a second outlet portion are fixed to a fixing member, and a connecting tube portion is provided between the first outlet portion and the second inlet portion. Further, the first inlet portion and the second inlet portionare arranged in a non-parallel state such that the distance between the two increases as they depart from the fixing member. The first outlet portion and the second outlet portion are similarly arranged in a non-parallel state, the first inlet portion and the second inlet portion and the first outlet portion and the second outlet portion being arranged symmetrically. Further, the first outlet portion, the second inlet portion, and the connecting tube portion are arranged such that their three tube axes are in a straight line.

Coriolis flowmeter having a fixing member with non-parallel inlet and outlet portions

Converter for flowmeter

A flow tube composed of a bent tube having a shape symmetrical with respect to a first axis is supported at its both ends by support portions having an outlet and inlet respectively. A drive device for alternately driving the flow tube rotationally about a second axis connecting the positions where the flow tube is supported is disposed on the vertical axis of a Coriolis flowmeter. A Pair of second drive devices for alternately driving the flow tube rotationally is disposed at positions laterally symmetrical with respect to the drive device. The paired second drive devices are driven in phase; the drive device is driven with the opposite phase to those of the second drive devices. A pair of vibration detecting sensors is disposed between the drive device and one of the second drive device and between the drive device and the other respectively. The sensors detect vibrations with phases the difference between which is in proportion to the Coriolis force acting on the flow tube disposed laterally symmetrically with respect to the drive device.

Coriolis flowmeter having a drive device driven in reverse phase to pair of second drive devices

A first inlet portion, a second inlet portion, a first outlet portion, and a second outlet portion are fixed to a fixing member, and a connecting tube portion is provided between the first outlet portion and the second inlet portion. Further, the first inlet portion and the second inlet portion are fixed so as to be in a non-parallel state such that the distance between the two increases as they depart from the fixing member, and the first outlet portion and the second outlet portion are similarly arranged in a non-parallel state. The first and second inlet portions and the first and second outlet portions are fixed so as to be arranged symmetrically. Further, the first outlet portion, the second inlet portion, and the connecting tube portion are arranged such that their tube axes are in a straight line. Further, the distance between driven portions is made small.

Coriolis flowmeter

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 mass flowmeter converter detects a Coriolis force acting on a flow tube driven at a constant frequency as a time difference .DELTA.T between two displacement signals detected at symmetrically opposed positions. A mass flow proportional to the time difference .DELTA.T is determined. Sine-wave signals differing in phase and at a constant amplitude are detected paired detecting coils and provide input signals which are pulses having specified pulse width values equal to a leading time (T+.DELTA.T) and a lagging time (T+.DELTA.T). N number of pulses (T+.DELTA.T) and N number of pulses (T-.DELTA.T) are sampled simultaneously by respective integrators having the same time constant, and by using a reference power source a time difference of zero-crossing voltages and a time difference signal enlarged by 2N times is detected. Furthermore, a small time measurement error due to drifts of the charging-discharging circuit is compensated by alternating respective integrators.

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Tokyo, Japan

Hirokazu Kitami