JPH0317225Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a flowmeter that calculates the fluid flow rate based on the displacement of a movable valve body that displaces the constriction part of the variable orifice flowmeter according to the fluid flow rate. It can be used in displacement detection type flowmeters, etc.

Prior Art To explain the prior art, a fixed valve seat is provided in a fluid flow path of a valve body, and a movable valve body is arranged in correspondence with the fixed valve seat to form a constriction portion. A technique is already known in which the amount of displacement of a movable valve body due to the flow rate of fluid flowing through a constriction part is read and calculated using a sensor placed outside the valve body and provided in the direction of displacement of the movable valve body. As the diameter of the valve body becomes larger, the amount of displacement of the movable valve element also increases, resulting in the sensor itself becoming larger, heavier, and more expensive. As a method to solve this drawback (for example, disclosed in Japanese Utility Model Publication No. 36-6577), the amount of displacement of the pressure receiving plate of the spring corresponding to the movable valve body connected to the movable valve body is determined by the displacement of the cam. A flowmeter that detects a scale display on a flow rate reading device through rotation, or (for example,
It is disclosed in Publication No. 18187. ) A flowmeter is known in which the displacement of the pressure receiving plate is electrically converted and displayed via a potentiometer by arranging a support shaft on the pressure receiving plate and connecting a rotating cam to the support shaft. be.

In these cases, the scale flow rate reading device using the former technology has difficulty in detecting small amounts due to its accuracy, and the latter has problems such as play between the support shaft and rotating cam, backlash, or hysteresis. The drawback was that it was difficult to adjust. In addition, there is a known flowmeter in which a differential displacement transformer is arranged, in which a movable iron core is brought into contact with a tapered part provided on the pressure receiving plate, and the minute displacement of the pressure receiving plate is detected by the output signal of a secondary coil. It has the disadvantage that it is easily influenced by magnetism, and its characteristics tend to change when there is a large difference between the liquid temperature and the ambient temperature.

Problems to be Solved by the Present Invention The present invention was developed in view of the above points, and its purpose is to improve the accuracy of detecting minute displacements of the movable valve body, and to avoid being affected by external magnetic effects. Another object of the present invention is to provide an inexpensive flow meter that can detect a fluid flow rate without being affected by the difference between liquid temperature and ambient temperature.

Means for Solving the Problems The present invention provides a fixed valve seat in a fluid flow path, and arranges a movable valve body corresponding to the fixed valve seat to form a constriction portion. In a flow meter that calculates the fluid flow rate based on the displacement of a movable valve body that is displaced in accordance with the fluid flow rate flowing through the section, the movable valve body is formed into a multistage taper plug, and a differential valve that reads the displacement of the movable valve body is used. A coil-type displacement sensor is disposed on the fixed wall contact side of the fluid flow path, and the movable core of the displacement sensor is brought into contact with the final taper portion 1a forming the fully open portion of the constricted portion of the multistage taper plug. It is characterized by:

Function: A fixed valve seat is provided in the fluid flow path, and a movable valve body is arranged in correspondence with the fixed valve seat to form a constriction part, and the movable valve body, which is displaced according to the fluid flow rate, is arranged in multiple stages. A differential coil type displacement sensor for reading the displacement of the movable valve body is disposed on the liquid contact side of the fixed wall of the fluid flow path, and the movable iron core of the displacement sensor is connected to the constricted portion of the multistage taper plug. By contacting the final tapered part forming the fully open part of the differential coil type displacement sensor, the displacement measurement part of the differential coil type displacement sensor becomes near the maximum flow velocity and is self-cleaned.
Hysteresis does not occur, improving the detection accuracy of minute displacements, and the valve body is closed and is not affected by external magnetic fields.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2. A fluid flow path communicating from a fluid inflow chamber 10 to an outflow chamber 11 passes through the valve body 9, and there is a fluid flow path in the fluid flow path. A fixed valve seat 12 is arranged to partition an inflow chamber 10 and an outflow chamber 11.

A pressure receiving plate 3 that moves integrally with the movable valve body 1 is provided on the upper part of the movable valve body 1 facing the fixed valve seat 12. A spring 4 that resists valve opening is connected to the pressure receiving plate 3.
A fixed wall side 16 that is brought into contact with and communicates with the outflow chamber 11
The pressure receiving plate forms a leak portion 17 with the fixed side walls 9a and 9b of the valve body 9.
The movable valve body 1 is fixed to a valve body 9, and is arranged to be vertically slidable using a central fixed guide shaft 5 disposed so as to pass through the fixed valve seat 12 as a guide, and is a multistage taper plug. The size of the diaphragm formed with the seat 12 is controlled to be variable.

Furthermore, the movable valve body 1 is attached to the fixed wall liquid contact side 6 of the valve body 9.
That is, a differential coil type displacement sensor 2 is installed to read the amount of displacement due to vertical sliding of a multistage taper plug (hereinafter referred to as multistage taper plug 1), and a movable iron core 13 made of a magnetic material of the differential coil type displacement sensor 2 is installed. is brought into contact with the taper portion 1a that forms the fully open portion of the multi-stage taper plug 1 after the final taper stage, that is, the constricted portion, and the displacement amount of the multi-stage taper plug 1 is detected from the direction perpendicular to the axis. It is located.

The differential coil type displacement sensor 2 includes the movable iron core 13 and a primary coil 7 and a secondary coil 8 disposed close to the movable iron core, and is movable by connecting an AC constant power supply circuit 14 to the primary coil. The displacement of the iron core is detected by the output signal of the secondary coil, and the fluid flow rate is calculated by the calculation circuit 15 based on the amount of displacement of the movable iron core.

To explain the operation of the embodiment, fluid pressure is applied to the upper and lower sides of the pressure receiving plate 3 according to the flow rate of fluid passing from the inflow chamber 10 to the outflow chamber 11, and the fluid is applied to the pressure inside the upper part of the pressure receiving plate and the resistance of the spring. When the pressure prevails, the multi-stage taper plug 1 is displaced relative to the fixed valve seat 12, and this displacement causes the movable core 13 of the differential coil type displacement sensor 2 to directly contact the multi-stage taper plug 1.
The fluid flow rate is calculated as the displacement amount. When a constant AC voltage is applied to the primary coil 7 by the AC constant power supply circuit 14, when the movable core is displaced, an induced electromotive force is induced in the secondary coil 8 for detection, and the amount of displacement of the movable core is determined by this voltage. It is calculated by .
(It is well known that the fluid flow rate is calculated from the amount of displacement and is not the gist of the present invention, so a detailed explanation will be omitted.) Effects of the Idea As described in detail above, the present invention uses a fixed valve in the fluid flow path. A throttle portion is formed by providing a seat and arranging a movable valve body corresponding to the fixed valve seat, and
The movable valve body that is displaced according to the fluid flow rate is a multistage taper plug, and a differential coil type displacement sensor that reads the displacement of the movable valve body is arranged on the liquid contact side of the fixed wall of the fluid flow path, and the displacement sensor is movable. Since the iron core was brought into contact with the final taper part 1a forming the fully open part at the constricted part of the multistage taper plug,
The flow rate is close to the maximum flow rate of the constriction part, so foreign matter does not accumulate and is self-cleaned, and the flow rate is geared to prevent hysteresis, increasing the accuracy of detecting minute displacements.Furthermore, the detection part detects the flow rate with the shortest stroke of the movable valve body. can. In addition, the valve body serves as a magnetic shield and is not affected by external magnetic fields.

Furthermore, the primary coil of the differential coil type displacement sensor,
Since the dynamic temperature of the flow itself acts uniformly on the secondary coil, there is no change in the sensor output due to the difference in heat transfer with the ambient temperature difference, especially in the case of high-temperature fluid, and this has no effect on accuracy.

The differential coil type displacement sensor as a whole is small and lightweight, making it inexpensive, and has a low movable weight and low friction, so changes in flow rate and displacement due to differences in mounting direction are extremely small.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the flowmeter of the present invention, and FIG. 2 is a vertical sectional view taken from FIG. 1. 1...Movable valve body, 2...Differential coil type displacement sensor, 6...Fixed wall liquid contact side, 12...Fixed valve seat.

Claims (1)

[Claims for Utility Model Registration] (1) A fixed valve seat is provided in the fluid flow path, and a movable valve body is disposed corresponding to the fixed valve seat to form a constricted portion, and the constricted portion In a flowmeter that calculates the fluid flow rate based on the displacement of a movable valve body that is displaced in accordance with the flow rate of fluid flowing through the flowmeter, the movable valve body is formed into a multistage taper plug, and a differential coil that reads the displacement of the movable valve body is used. A mold displacement sensor is disposed on the fixed wall contacting side 6 of the fluid flow path, and the movable iron core of the displacement sensor is brought into contact with the final taper portion 1a forming the fully open portion at the constricted portion of the multistage taper plug. A flow meter. (2) The flowmeter according to claim 1, wherein the differential coil type displacement sensor is arranged to read the displacement of the movable valve body in a scaleable manner.