Oval Corporation

Yuichi Nakao

Seiji Kobayashi

Norio Sukemura

Yasushi Ito

Hirokazu Kitami

Yasuichi Shiraishi

Naoki Matsubara

Yutaka Ogawa

Masao Misumi

Kenichi Matsuoka

Shingo Gomi

Katsuichi Uchida

Satoru Nihei

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

A tertiary mode vibration type Coriolis flowmeter includes a flow tube, a drive device driving the flow tube, and a pair of vibration detecting sensors detecting a phase difference in proportion to a Colioris force acting on the flow tube. The drive device drives the flow tube by bending vibration in a tertiary mode. The flow tube further comprises an approximately loop-shaped body part. A pair of parallel leg parts deflected in a direction approximately orthogonal to the vibrating direction of both end parts of the body part, namely, to the outside of the both end parts are formed continuously with the both end parts of the body part. Fixed end parts supporting the flow tube are formed at the leg parts.

Tertiary mode vibration type coriolis flowmeter

A Coriolis flow meter () with a vibrating direction restriction means includes flow tubes (), a drive means () for driving the flow tubes (), and phase difference detection means () for detecting a phase difference in proportion to a Coriolis force. The Coriolis flow meter further includes plate springs () functioning as vibrating direction restriction means, and a flow tube fixing member () also functioning as a vibrating direction restriction means and serving to fix the flow tubes () in position.

Coriolis flow meter with vibrating direction restriction means

A straight tube type Coriolis flowmeter is equipped with a straight-tube-type flow tube, a drive device for driving by a tertiary mode vibration, a pair of detection unit for detecting a phase difference proportional to a Coriolis force, a pedestal having rigidity, and elastic connection members having elasticity. Assuming that an axial direction of the flow tube is a Z-axis, that a driving direction of the drive device is an X-axis, and that a direction orthogonal to the Z-axis and the X-axis is a Y-axis, the elastic connection members are of a structure exhibiting lower rigidity in the Z-axis direction than in the X-axis direction and the Y-axis direction, and exhibiting lower rigidity in a direction of rotation around the Y-axis than in a direction of rotation around the Z-axis and a direction of rotation around the X-axis.

Straight tube type Coriolis flowmeter for tertiary mode vibration with elastic connection member and pedestal

A start tube section () of a first bent tube () has a first parallel subsection () substantially parallel to a start tube section () of a second bent tube () or to a continuous section () between a return tube section () of the first bent tube () and the start tube section () of the second bent tube (), a first bent subsection () continuous with the first parallel subsection (), and a first start tube section body subsection () extending gradually away from the start tube section () of the second bent tube () due to presence of the first bent subsection (). A return tube section () of the second bent tube section () has a second parallel subsection () substantially parallel to the return tube section () of the first bent tube () or to the continuous section (), a second bent subsection () continuous with the second parallel subsection (), and a second return tube section body subsection () extending gradually away from the return tube section () of the first bent tube () due to presence of the second bent subsection ().

Coriolis flow rate meter with flow tube of double loop structure

In order that a flow tube of a Coriolis flowmeter may be vibrated in a tertiary mode using one drive device, the drive device is arranged at an antinode in the center of tertiary mode vibration, and vibration detecting sensors are arranged at two antinodes other than the antinode in the center of tertiary mode vibration. Moreover, the displacement polarity of the drive device is opposite to that of the vibration detecting sensors so that the vibration phases of the flow tube are in a relation of mutually opposite phases. Furthermore, in a positive feedback loop of an excitation circuit portion for exciting tertiary mode vibration of the flow tube and the vibration detecting sensors , the excitation circuit portion is structured so that the relation between the displacement polarities where the vibration phases of the flow tube are opposite to one another is converted to the relation where the vibration phases of the flow tube are in phase.

Tertiary mode vibration type Coriolis flowmeter

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

The Coriolis mass flow meter of this invention comprises two parallel curved flow tubesanda drive unitand a pair of vibration sensorsandAn inlet-side manifolddividing the flow of a fluid being measured into the two flow tubesandfrom the inlet thereof, and an outlet-side manifoldjoining the fluid flows flowing in the two flow tubesandto discharge from the fluid outlet thereof are mechanically connected to a meter bodyonly at the inlet side of the inlet-side manifoldand at the outlet side of the outlet-side manifoldrespectively. With this arrangement, the effects of vibration transmitted from the meter bodyand all structures connected thereto can be reduced at the joint parts between the inlet-side and outlet-side manifoldsandthat serve as vibration fulcrums.

Coriolis mass flowmeter

Two flow tubes and of a Coriolis mass flow meter are formed into an arch shape, with the tubes bent in only one direction. Entry-side and exit-side manifolds are smoothly bent from the inlet of the entry-side manifold and the outlet of the exit-side manifold to joints connecting the two flow tubes to the manifolds, and connected to the flow tubes and at the joints at a predetermined angle in the same direction. By making the flow tubes into a parallel arched tube structure having good stress distribution and shock resistance, effects on the flow meter of external oscillations, installation conditions, piping stresses and thermal stresses can be reduced.

Coriolis mass flow meter

Each of two flow tubes assumes an arcuate shape consisting of a central arcuate segment and two linear segments located on opposite sides of the central arcuate segment. The inside diameter of the flow tubes and the linear distance between end points of each of the flow tubes are determined on the basis of a target pressure loss arising from passage of a fluid to be measured through a manifold and the flow tube at the maximum flow rate, a target time phase difference between sine wave outputs from vibration sensors at the maximum flow rate, and a target natural frequency of the flow tubes. The length of the linear segments is selected so as to reduce thermal stress induced from an abrupt change in the temperature of the fluid to be measured, and the shape of the flow tubes is determined so as to reduce the vertical height of the flow tubes, so long as the thermal stress is substantially constant even when the length of the linear segments is varied. Thus, the shape of the flow tubes is determined in such a manner as to suppress, to a predetermined low value, stress arising upon abrupt change in the temperature of the fluid to be measured and as to be most compact.

Arch-shaped tube type coriolis meter and method for determining shape of the coriolis meter

A Coriolis mass flowmeter of a type in which a fluid to be measured is caused to flow in series by forming two parallel flow tubes and which are obtained by bending one conduit. The inlet portion of conduit between an external connecting portion connected to inlet piping and the inlet of one flow tube is bent in the shape of the letter L and bent in another direction in combination, and the outlet portion of conduit between an external connecting portion connected to outlet piping and the outlet of the other flow tube is bent in the shape of the letter L symmetrically with respect to the above inlet portion of conduit and bent in another direction in combination. The external connecting portions and are arranged on the same axis. The present invention simplifies the construction of connection to external piping, simplifies the assembling of the Coriolis mass flowmeter itself, and permits a high-accuracy measurement of mass flow rate by reducing the vibrations of external piping, etc.

Coriolis mass flowmeter and method of making same

A vortex flow meter capable of operating with minimum piping effect is disclosed. A stream-lined protrusion , extending toward the upstream side is disposed at the upstream surface 2 of a vortex generator joined to the inner wall 1 of a flow pipe in order to remove thereat horseshoe vortexes produced in front of the vortex generator. Therefore, the possible affection of horseshoe vortexes, that may considerably depend upon the piping conditions, can be eliminated.

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Tokyo, Japan

Yuichi Nakao