JPS5890127A - Flowmeter - Google Patents

Abstract

PURPOSE:To maintain the inside of a cylinder clean at all times for keeping an excellent sensitivity, by previously filling the inside of the cylinder with a fluid which will hardly diffuse into a fluid to be measured. CONSTITUTION:Fluid inlet/outlets 8, 9 communicating with front and rear chambers 6, 7 in a cylinder 1 defined by a piston 4 are opened in the side surfaces of covers 2, 3 of a flowmeter, respectively. The inlet/outlets 8, 9 are connected through a four-way valve 12 so as to be able to alternately connect to a pipe 10 communicating with the source of a fluid to be measured and a pipe 11 communicating with the discharge side of a surge tank or the like. The cylinder 1 is filled with a clean fluid B which will not corrode the cylinder 1, the piston 4 and so forth and will hardly diffuse into a fluid A to be measured, e.g., water for gasoline, and alcohol for lubricating oil. By this constitution, the inside of the cylinder can be maintained clean at all times, so that it is possible to keep an excellent sensitivity.

Description

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

In order to maintain good sensitivity of this free piston type flow needle, it is necessary to keep the inside of the cylinder clean at all times.

The present invention was proposed in view of the above.

The gist is that the cylinder is filled in advance with a fluid that is difficult to diffuse against the fluid to be measured.

The volume of fluid that is difficult to diffuse, which is filled before and after the above-mentioned screws, is larger than the stroke volume caused by the displacement of the piston.

The structure of the embodiment shown in the drawings will be explained below. 1 is a transparent glass cylinder, 2 and 6 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. An end plate 41 made of a conductive material such as aluminum is bonded or lightly press-fitted into the end opening of a cylinder made of a non-conductive material such as resin as a detection target material. The piston 4 can also be hollow by closing both end faces.

A non-contact displacement detector 5 using eddy current is attached to the inner surface of one lid 2 facing the end plate 41 of the piston 4, and is connected to a signal converter (not shown).

On the sides of the can lids 2 and 3, there are fluid inlets and outlets 8 and 8 that communicate with the front chamber 6 and rear chamber 7 of the cylinder 1, respectively, which are partitioned by the piston 4.
9 is open.

The fluid inlet/outlet ports 8 and 9 are connected to a pipe 10 leading to the source of the fluid to be measured.
and a pipe 11 leading to the exit side of a surge tank or the like through a four-way valve 12 so as to be connectable alternately.

In the cylinder 1, there is a fluid 1 that is difficult to diffuse with respect to the fluid to be measured A, for example, water compared to gasoline.

The lubricating oil is filled with a clean fluid B that has no risk of damaging the cylinder 1 or piston 4 containing alcohol.

The filling amount of fluid B in front of the piston 4 and at the ridge is greater than the maximum stroke volume due to the displacement of the piston 4.

When the fluid A to be measured is sent with the four-way valve 12 set to the solid line water position, the fluid B in the front chamber 6 is pushed by the fluid A, causing the piston 4 to retreat. Fluid B in the rear chamber 7 and fluid A in the tube 11 are pushed out by the piston 4.

As the piston 4 retreats as described above.

The voltage generated in the detector 5 increases, and the voltage is transferred to the piston 4.
can be seen as a displacement lid. Therefore, the flow rate can be determined based on the amount of displacement and the time required for the displacement.

When the piston 4 reaches the retraction end, the four-way valve 12 is turned 90 degrees counterclockwise in the figure, and the flow path within the four-way valve 12 is switched as shown by the chain line, causing fluid A to flow into the cylinder 1. The direction is reversed and the piston XX\4 moves forward and returns to its original position.

The present invention is a free piston type flowmeter using a non-contact drop detector, in which the cylinder 1 is filled in advance with a fluid B that is difficult to diffuse with respect to the fluid A to be measured. Even if the fluid A is a chemical, an erosive fluid, a polluted fluid, etc., it can be measured.

In addition, since the filling amount of the fluid B that is difficult to diffuse before and after the piston 4 is made larger than the stroke volume caused by the displacement of the piston 4, the fluid A to be measured is filled into the cylinder 1.
can be reliably prevented from entering.

Therefore, the sliding portion between the piston 4 and the cylinder 1 is always kept clean, the sensitivity is improved, and accurate measurements can be made, making it suitable for measuring minute flow rates.

In the figure, reference numerals 16 and 14 are chambers for separating foreign matter, air bubbles, etc. in the fluid A, which are provided in the container pipes 10 and 11 between the cylinder 1 and the switching cock 12.

[Brief explanation of the drawing]

The figure is a longitudinal sectional front view of the flowmeter of the present invention. 1 is a cylinder, 2 and 3 are lids, 4 is a piston, 41 is a material to be detected, 5 is a detector, A is a fluid to be measured, and B is a fluid that is difficult to diffuse.

Claims (2)

[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 inflow of fluid using a non-contact detector. A flowmeter characterized in that a cylinder is filled in advance with a fluid that is difficult to diffuse against the fluid to be measured. (2) In a flowmeter that measures the flow rate by detecting the displacement of a free piston that moves within a cylinder due to the inflow of fluid using a non-contact detector. The cylinder is filled in advance with a fluid that is difficult to diffuse compared to the fluid to be measured, and the amount of the fluid that is difficult to diffuse before and after the piston is made larger than the stroke volume caused by the displacement of the piston. Flow meter.