JPH06103200B2 - Flowmeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a tubular body in which a vapor phase such as steam and a liquid phase such as condensate flow in layers. The present invention relates to a flow meter that measures each flow rate of a gas phase and a liquid phase.

<Prior Art> Generally, steam and condensate flow through the same pipe, but sometimes it is necessary to measure the flow rates of both steam and condensate. In such a case, as shown in FIG.
Pipe 2 for steam only in the middle of pipe 1 through which steam and condensate flow
And a pipe 3 dedicated to condensate, a flow meter 4 for steam is arranged in the pipe 2, and a flow meter 5 for condensate is arranged in the pipe 3 to measure both flow rates. It was

<Problems to be Solved by the Invention> However, in such a technique, dedicated pipes 2 and 3 are required for steam and condensate, and although not shown in FIG. Since a device such as a separator is required, there is a problem that the entire device becomes large.

The present invention is to be able to measure each flow rate of a gas phase and a liquid phase without separating the gas phase and the liquid phase.

<Means for Solving the Problems> The technical means of the present invention taken to solve the above technical problems is a tubular body in which a gas phase and a liquid phase flow in layers, and A vortex generator that is a vertically arranged electrode, a vibration sensor that detects the vibration generated by this vortex generator, and a gas-phase filter and liquid that allow only the vibration signal due to the gas phase to pass through among the signals from this vibration sensor. A liquid phase filter that allows only the vibration signal due to the phase to pass, and a means for calculating each flow velocity of the gas phase and the liquid phase from the respective transmitted signals.
Means for calculating the liquid level from the electric signal between the vortex generator and the pipe, and the respective flow rates of the gas phase and the liquid phase based on the liquid level and the respective flow velocities of the gas phase and the liquid phase. It is in a flowmeter consisting of means for calculating.

<Operation> The operation of the above technical means is as follows.

Karman vortices are regularly generated on the downstream side of the vortex generator placed in the flow, and the number of occurrences (frequency f) and the flow velocity u have the relationship of the following formula (1). Therefore, by multiplying the flow velocity u by the passage cross-sectional area S as in the following equation (2),
The flow rate Q can be obtained.

f = st ・ (u / d) ・ ・ ・ (1) Q = S ・ u ・ ・ ・ (2) where st is the Strouhal number, u is the velocity of the fluid passing through the vortex generator, and d is the vortex. It is the width of the generator (the diameter in the case of a cylinder).

According to the flow meter of the present invention, the vortex frequencies of the gas phase and the liquid phase are extracted from the combined vortex frequencies of the gas phase and the liquid phase generated by the vortex generator, and the gas phase is calculated by the equation (1). Calculate each flow rate of the liquid phase. Further, by detecting the liquid level as a change in resistance or capacitance between the electrode and the tube, it is possible to obtain the cross-sectional areas of passage of the gas phase and the liquid phase flowing in the tube. Each flow rate of the gas phase and the liquid phase can be calculated and calculated from the flow velocity and the step area thus obtained.

<Example> An example showing a specific example of the present invention will be described. (See FIG. 1).

Reference numeral 10 denotes a tubular body in which a gas phase 12 flows at a flow rate u1 and a liquid phase 14 flows at a flow rate u2 from left to right in the figure. A vortex generator (16) is arranged at the center of the inside of the tube (10) perpendicularly to the tube (10) and fixed from the outside of the tube (10) with a bolt (18). The vortex generator 16 is a ceramic outer cylinder having a bottomed cylindrical shape and a flange formed at the upper end.
It is composed of 20 and an electrode rod 22 press-fitted therein.

The electrode rod 22 and the tubular body 10 are connected to a calculator 24 via conductors, respectively, and the calculator 24 calculates the liquid level from the change in electrostatic capacity, and the vapor phase is calculated.
Calculate the cross-sectional area of passage of each of 12 and the liquid phase 14.

The vibration sensor 26 is attached to the upper surface of the electrode rod 22. The signal from vibration sensor 26 is coupled to amplifier 28 via a conductor.
Reference numeral 30 is a heat insulating member, and 32 is a cover.

The gas-phase flow 12 and the liquid-phase flow 14 that flow in the tube body 10 separate on both sides of the vortex generator 16 and are entrained in the vortex, and generate an oscillating wake downstream of the vortex generator 16. This wake is the emission frequency f of the Karman vortex.
It vibrates at and attenuates due to viscosity as it goes downstream, returning to a steady flow. The frequency f is a combination of vibrations generated by the gas-phase flow and the liquid-phase flow, and is detected by the vibration sensor 26.

The vibration signal detected by the vibration sensor 26 is amplified by the amplifier 28 and flows to the gas phase filter 34 and the liquid phase filter 36. Here, the relationship between the vortex frequency and the flow velocity in the gas phase and the relationship between the vortex frequency and the flow velocity in the liquid phase are known in advance. analyse. That is, only the range of the vortex frequency that can occur in each phase is left and the other vortex frequency regions are removed. The counter 38 counts the vortex signals output from the gas phase and liquid phase filters 34 and 36, respectively, and the calculator 24 calculates the vortex signals (1).
The gas phase flow rate u1 and the liquid phase flow rate u2 are calculated based on the equations.

Then, the calculator 24 further calculates the flow rate of each phase from the flow velocity and the cross-sectional area of each phase based on the equation (2).

<Effects of the Invention> Since the flowmeter disclosed in Japanese Patent Laid-Open No. 51-99561 determines each flow rate assuming that the flow rates of the gas phase and the liquid phase are the same, the flow rates of the gas phase and the liquid phase are If they are different, an accurate flow rate cannot be obtained. In the present invention, since the respective flow velocities of the gas phase and the liquid phase are calculated, each flow rate can be accurately obtained.

Therefore, if the flow meter of the present invention is provided, for example, between the steam using device and the steam trap, particularly on the side close to the steam trap, the amount of steam used in the device using steam (amount of condensed water)
Also, the amount of steam leak in the steam trap can be accurately measured. Further, if it is provided on the inlet side of the steam using device, the amount of steam used and the amount of condensate mixed in can be accurately measured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a flow meter according to the present invention, and FIG. 2 is a piping diagram of a conventional flow meter. 10: Tube, 12: Gas phase 14: Liquid phase, 16: Vortex generator 20: Outer cylinder, 22: Electrode rod 24: Calculator, 34: Gas phase filter 36: Liquid phase filter

Claims (1)

[Claims] 1. A tube body in which a gas phase and a liquid phase flow in layers,
A vortex generator that is an electrode that is arranged perpendicularly to this tube, a vibration sensor that detects the vibration generated by this vortex generator, and a Between the vortex generator and the tubular body, a liquid phase filter for transmitting only the vibration signal due to the phase filter and the liquid phase, a means for calculating the respective flow velocities of the gas phase and the liquid phase from the respective transmitted signals. A flow meter comprising means for calculating the liquid level from the electric signal of 1. and means for calculating the respective flow rates of the gas phase and the liquid phase based on the liquid level and the flow rates of the gas phase and the liquid phase.