JPS5890128A - Flowmeter - Google Patents

Abstract

PURPOSE:To improve a sensitivity of flowmeter, by disposing non-contact detectors at both ends of a cylinder so as to face members to be detected which are provided on both end surfaces of a piston, and composing outputs simultaneously generated from both detectors. CONSTITUTION:Non-contact displacement detectors 5, 6 to actuate by eddy current are attached to the inner surfaces of covers 2, 3 so as to face end plates 42, 43 of a piston 4 of a flowmeter and connected to signal converters, respectively. Fluid inlet/outlets 9, 10 communicating with front and rear chambers 7, 8 of a cylinder 1 defined by the piston 4 are opened in the side surfaces of the covers 2, 3, respectively. The outputs simultaneously generated from both detectors 5, 6 are composed to form a signal. Accordingly, the detection sensitivity is amplified for the movement of the piston. In addition, a satisfactory sensitivity is shown even if the piston displacement amount and its speed are small with respect to the piston diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flowmeter that measures the flow rate by detecting the displacement of a free piston that moves within a cylinder due to fluid delivery using a non-contact type detector. be.

The purpose of this free piston flowmeter is to improve sensitivity, which is essential for controlling minute flow rates.

That is, non-contact type detectors attached to the cylinder are placed at both ends of the cylinder, facing the detected material provided on both end faces of the piston, and the outputs generated simultaneously from both detectors are combined to obtain a measurement signal. The gist is what has been constructed.

The structure of the embodiment shown in the drawings will be explained below. 1 is a cylinder made of transparent glass, 2 and 3 are lids that close the openings at both ends of the cylinder 1, and 4 is a free piston that slides inside the cylinder 1, as shown in FIG. 2. A cylindrical body 410 made of a non-conductive material such as glass, ceramics, synthetic resin, etc. has openings at both ends as a material to be detected.

It is made hollow by lightly press-fitting or gluing end plates 42 and 46 made of a conductive material such as aluminum. The piston 4 may have a cylindrical portion and both end surfaces formed into a hollow integral piece, and a conductive material may be attached to the outside of each end surface.

Eddy current non-contact displacement detectors 5 and 6 are attached to the inner surfaces of the can lids 2 and 6 facing the end plates 42 and 46 of the piston 4, respectively, and are connected to a signal converter (not shown). .

Fluid inlet/outlet ports 9 and 10 are opened on the side surface of the can lid 2I+6, which communicate with the front chamber 7 and rear chamber 8 of the cylinder 1, which are partitioned by the piston 4, respectively.

The fluid inlet/outlet ports 9 and 10 are pipes 1 leading to the fluid source to be measured.
1 and a pipe 12 leading to the discharge side of a surge tank or the like via a four-way valve 16 so as to be alternately connectable.

When fluid is sent with the west valve 16 set to the solid line position 1k in FIG. 1, the fluid flows from the pipe 11 into the front chamber 7 of the cylinder 1, causing the piston 4 to retreat. The fluid previously contained in the rear chamber 8 is forced out by the piston 4 and flows into the pipe 12 via the four-way valve 13.

As the piston 4 moves backward, the voltage generated in the detector 5 on the front chamber side increases, and this voltage can be seen as the amount of displacement of the piston 4. At the same time, the voltage generated at the rear chamber side detector 5 decreases, but this is reversed to the positive side and the front side detector 5
In addition to the voltage, the combined output is used as a measurement signal, and the output representing the amount of displacement of the piston 4 is amplified twice. The flow rate is determined by the piston displacement lid and the time required for its displacement.

When the piston 4 reaches the retraction end, the four-way valve 13 is turned 90 degrees counterclockwise as shown in Figure 9, and the flow path inside the four-way valve 13 is switched as shown by the chain line. The inflow direction is reversed, and the piston 4 moves forward and returns to its original position. If the detectors 5 and 6 are operated when the piston 4 is returned to its original position, continuous reciprocating measurements can be made.

The present invention is a free piston type flow lid using non-contact detectors, in which non-contact detectors a5 and 6 are placed at both ends of the cylinder 1, facing the detected materials 42 and 46 on both end surfaces of the piston 740. Since it is configured to generate a signal by combining the outputs generated simultaneously from both detectors 5 and 6, the detection sensitivity for the movement of the piston is amplified, and the detection sensitivity for the piston diameter is amplified.

It exhibits sufficient sensitivity even if its displacement amount and displacement speed are small, and is particularly suitable for microflow meters that require high sensitivity.

Note that if the piston 4 is made hollow as in the embodiment, buoyancy is generated and friction with the cylinder 1 is reduced.

Furthermore, if both end faces of the piston 740 are made of thin plates of the material to be detected, it will be even lighter, and will move more sensitively even with minute flow rates, which is effective in improving sensitivity.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of the flowmeter of the present invention, and FIG. 2 is an exploded perspective view of the piston. 1 is a cylinder, 2 and 6 are lids, 4 is a piston, 5 and 6 are detectors, and 42 and 43 are materials to be detected. Patent applicant Honda Motor Co., Ltd. Figure 2

Claims (1)

[Claims] (1) In a flowmeter that measures the flow rate by detecting the displacement of a free piston that moves within a cylinder due to the supply of fluid with a non-contact detector. A flow rate characterized in that non-contact type detectors are arranged at both ends of the cylinder to face the detected material provided on both end surfaces of the piston, and the outputs generated simultaneously from both detectors are combined to obtain a measurement signal. Total.