JP2001027595A - Steam dryness measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a steam dryness measuring apparatus having a wide measurable range of dryness and capable of simply measuring dryness. SOLUTION: An ultrasonic transceiver 2 is attached to the outer surface of the bottom portion of a steam piping 1 through which steam to be measured flows down and a pressure sensor 4 for detecting steam pressure is attached to the steam piping 1 and both of the transceiver 2 and the pressure sensor 4 are connected to a control operator 3. The pressure of the steam piping 1 detected by the pressure sensor 4 is inputted to the control operator 3 and a relation between the specific vols. and steam pressures of saturate steam and saturated water is preliminarily stored in the control operator 3. The control operator 3 controls the ultrasonic transceiver 2 at every predetermined time to emit ultrasonic waves upwardly from the outer surface of the bottom portion of the steam piping 1 and detects the water level of the steam piping 1 from the time required until ultrasonic waves are reflected from the surface of the water to return. The vols. of steam and drain are calculated from the detected water level and the dryness of steam is calculated from the calculated volms. and the preliminarily stored specific vols. of saturated steam and saturated water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the moisture content in a steam pipe, that is, the dryness of steam indicating the ratio of the mass occupied by steam to the total mass per unit volume. In various boilers, equipment using steam power, and drying equipment, it is necessary to measure the dryness of steam for heat management. This is because the enthalpy of the steam varies depending on the water content.

[0002]

2. Description of the Related Art As a conventional steam dryness measuring apparatus, there is an aperture dryness meter for measuring the dryness of steam by using a change in isenthalpy of steam. This is achieved by injecting wet steam into the measuring vessel through the nozzle and adiabatic expansion (equal enthalpy change) to produce superheated steam, and detecting the pressure upstream of the nozzle and the pressure and temperature in the measuring vessel to form the Moliere wire. The dryness is measured by using a diagram or a saturated steam table and a superheated steam table.

[0003]

The conventional dryness meter described above has a problem that the range of measurable steam pressure and dryness is limited, and only a part of wet steam can be measured. That is, when the pressure and the dryness of the wet steam to be measured are low, the superheated steam state does not occur after the adiabatic expansion. Therefore, a technical problem of the present invention is to provide a steam dryness measuring device that has a wide range of measurable dryness and can easily measure the dryness.

[0004]

Means for Solving the Problems The technical means of the present invention which has been taken to solve the above technical problem includes an ultrasonic transceiver mounted on the outer surface of the bottom of the steam pipe, and Water level detecting means for detecting the water level in the steam pipe from the time until the ultrasonic waves radiated toward the surface are reflected and returned, and volume calculating means for calculating the volume of steam and drain from the detected water level And a dryness calculating means for calculating the dryness of the steam from the calculated volumes of the steam and the drain and the specific volumes of the saturated steam and the saturated water stored in advance. In the device.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An ultrasonic wave radiated upward from an ultrasonic transmitter / receiver attached to the bottom outer surface of a steam pipe through which steam to be measured flows is reflected from the surface of the water and returned from the time until the ultrasonic wave returns. Detects the water level in the steam pipe. The areas of the steam section and the drain section are calculated from the detected water level, and the volumes of the steam and the drain at a unit length of the steam pipe are calculated from the calculated areas. The weights of the steam and the drain are calculated from the calculated volumes and the specific volumes of the saturated steam and the saturated water stored in advance, and the dryness of the steam is calculated from the calculated weights.

As described above, the present invention detects the water level in a steam pipe through which the steam to be measured flows, calculates the volumes of steam and drain from the detected water levels, and calculates the calculated volume and the saturated steam. Further, since the dryness of the steam is calculated from the specific volume of the saturated water, it is not necessary to bring the steam into a superheated steam state. Therefore, the range of the measurable dryness is wide, and the dryness can be easily measured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment showing a specific example of the above technical means will be described (see FIGS. 1 and 2). An ultrasonic transmitter / receiver 2 is attached to the bottom outer surface of the steam pipe 1 through which the steam to be measured flows,
Connected to the control computing unit 3. In addition, steam pipe 1
The pressure sensor 4 for detecting the pressure of the pressure sensor 4 is attached and connected to the control arithmetic unit 3. A temperature sensor may be attached to the steam pipe 1 instead of the pressure sensor 4, and the pressure of the steam pipe 1 may be obtained by the control calculator 3 from the detected temperature. When the pressure of the steam pipe 1 is known, the pressure may be directly input to the control calculator 3 without attaching a pressure sensor or a temperature sensor. The control calculator 3 receives the pressure of the steam pipe 1 detected by the pressure sensor 4 and stores in advance the relationship between the specific volume of saturated steam and saturated water and the steam pressure.

The control arithmetic unit 3 controls the ultrasonic transmitter / receiver 2 at predetermined time intervals to radiate ultrasonic waves upward from the bottom outer surface of the steam pipe 1 until the ultrasonic waves are reflected by the water surface and returned. The water level of the steam pipe 1 is detected from the time, the area S1 of the steam section and the area S2 of the drain section are calculated from the detected water level, and the unit length of the steam pipe 1 is calculated from the calculated area S1 of the steam section and the area S2 of the drain section. Then, the volume V1 of the steam and the volume V2 of the drain are calculated.

The arithmetic and control unit 3 calculates the steam weight M1 by multiplying the calculated steam volume V1 by the reciprocal of the specific volume of the saturated steam based on the pressure of the steam pipe 1, and calculates the calculated drainage M1. The volume V2 is multiplied by the reciprocal of the specific volume of the saturated water based on the pressure of the steam pipe 1 to calculate the weight M2 of the drain. From the calculated weight M1 of the steam and the weight M2 of the drain, the dryness X of the steam is calculated as X = M1 / (M1 + M2)
Is calculated and output.

[0010]

As described above, according to the present invention, the dryness can be measured without overheating the steam by calculating the dryness from the water level in the steam pipe. As it becomes wider, an excellent effect that the dryness can be easily measured is produced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a steam pipe showing a configuration of a steam dryness measuring apparatus according to the present invention.

FIG. 2 is a cross-sectional view of a steam pipe showing a configuration of a steam dryness measuring apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Steam piping 2 Ultrasonic transceiver 3 Control arithmetic unit 4 Pressure sensor

Claims (1)

[Claims] An ultrasonic transmitter / receiver attached to an outer surface of a bottom of a steam pipe, and an ultrasonic wave radiated upward from the ultrasonic transmitter / receiver is reflected from a surface of the water and returned to the inside of the steam pipe. Water level detecting means for detecting the water level of the water, volume calculating means for calculating the volume of steam and drain from the detected water level, and the ratio of the calculated steam and drain volume to the previously stored saturated steam and saturated water. A dryness calculating means for calculating dryness of steam from a volume.