JP4011473B2 - Steam dryness measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring so-called dryness: X, which indicates the moisture content in steam, that is, the ratio of the mass of dry saturated steam to the total mass per unit volume of steam. Thus, when the dryness is X, the wetness can be obtained as (1-X). In various boilers, equipment using steam power, drying equipment, etc., it is necessary to measure the dryness of steam for heat management. This is because, for example, the dry state changes depending on the moisture content in the steam.
[0002]
[Prior art]
In this, the first flow meter and the first pressure sensor, the throttle mechanism, the second flow meter and the second pressure sensor are attached to the steam pipe through which the steam flows down. A vapor dryness measuring apparatus for measuring the dryness of flowing steam is disclosed.
[0003]
[Problems to be solved by the invention]
In the above conventional steam dryness measuring device, in addition to a plurality of flow meters attached to the steam pipe, a throttle mechanism and a second pressure sensor are necessary, and the number of members increases and the device becomes complicated and expensive. There was a problem.
[0004]
Accordingly, an object of the present invention is to provide a vapor dryness measuring apparatus that can omit members such as a throttle mechanism, has a simple structure, and is inexpensive.
[0005]
[Means for Solving the Problems]
The means of the present invention devised to solve the above problem is that a plurality of flow meters are arranged in a steam pipe through which steam flows and a pressure sensor or temperature sensor for detecting the pressure or temperature of the steam is attached, For measuring the dryness or wetness of steam, a volumetric flow meter that detects the volumetric flow rate of the flowing steam and a mass flowmeter that detects the mass flow rate of the flowing steam are arranged in series, respectively. From the detected value from the flow meter and the pressure value or temperature value of the steam, the volume flow value of the steam in the positive flow meter: A and the mass flow value of the steam in the mass flow meter: M to A / M = V From the equation, V, that is, the specific volume of the mixed fluid of steam and water droplet condensate is obtained, the specific volume of saturated water is V1, the specific volume of saturated steam is V2, and the dryness of steam is X. , V = V1 + X (V2-V1) Based, are those provided with the arithmetic control unit for calculating the dryness fraction or wetness of the steam flow.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The volumetric flow rate value A of the steam is detected by the volumetric flow meter, while the mass flow rate value M of the steam is detected by the mass flow meter, and V is obtained from the A / M = V formula, that is, the steam and water droplets are restored. The specific volume of the mixed fluid with water is obtained. Further, if the specific volume of saturated water is V1, the specific volume of saturated steam is V2, and the dryness of steam is X, the relational expression V = V1 + X (V2−V1) holds, and V1 and V2 are obtained from the steam table. The dryness of steam: X can be obtained by reading and inputting, or by reading from a steam table stored in advance in the arithmetic control unit.
[0007]
【Example】
In FIG. 1, a steam pipe 1 through which steam flows, a volumetric flow meter 2 and a mass flow meter 3 attached in series to the steam pipe 1, and a pressure attached to the steam pipe 1 between both flow meters 2 and 3. The sensor 4, the temperature sensor 5, and the calculation control unit 6 constitute a vapor dryness measuring device.
[0008]
As the volumetric flow meter 2, a conventionally known one such as a vortex flow meter using an Karman vortex, an ultrasonic flow meter, a throttle flow meter, or an area flow meter can be used. Similarly, a Coriolis flow meter or the like can be used as the mass flow meter 3.
[0009]
A pressure sensor 4 for detecting the pressure of steam in the pipe and a temperature sensor 5 for detecting temperature are attached to the steam pipe 1 between the flow meters 2 and 3. When reading the specific volume of saturated water and the specific volume of saturated steam from the steam table, when reading based on the steam pressure, use the detected value from the pressure sensor 4, while when reading based on the steam temperature A detection value from the temperature sensor 5 is used. Therefore, in order to read the specific volume of saturated water and saturated steam, it is only necessary to know either pressure or temperature.
[0010]
The flow meters 2 and 3 and the sensors 4 and 5 are electrically connected to the calculation control unit 6. The arithmetic control unit 6 incorporates a storage unit (not shown) and stores in advance at least the specific volume for each pressure and temperature in the steam table. The entire steam table can be stored in advance in the storage unit.
[0011]
In order to measure the dryness: X or the wetness: (1-X) of the steam flowing down in the steam pipe 1, first, the volumetric flow rate value: A of the steam is detected by the volumetric flow meter 2, while the mass flow rate is detected. The mass flow rate value M of the steam is detected by a total of 3 and V is calculated from the A / M = V equation, that is, the specific volume of the mixed fluid of steam and condensate is obtained by the arithmetic control unit 6, and then the arithmetic control unit From the specific volume of saturated water: V1 and the specific volume of saturated steam: V2 which are stored and read in FIG. 6, the dryness of the steam using the relational expression V = V1 + X (V2−V1) stored in the same way : X can be obtained.
[0012]
In the present embodiment, the example in which the volumetric flow meter 2, the mass flow meter 3, the pressure sensor 4 and the temperature sensor 5 are separately attached to the steam pipe 1 is shown, but these are integrated as a sensing unit. Thus, by changing a part of the existing steam pipe, the steam dryness measuring device unit can be easily attached or detached.
[0013]
【The invention's effect】
As described above, according to the present invention, by disposing the volumetric flow meter and the mass flow meter in series, members such as a throttle mechanism can be omitted, and a vapor dryness measuring device that has a simple structure and is inexpensive. Obtainable.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vapor dryness measuring apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steam piping 2 Volumetric flow meter 3 Mass flow meter 4 Pressure sensor 5 Temperature sensor 6 Calculation control part

Claims (1)

In a system that measures the dryness or wetness of the flowing steam by installing a plurality of flow meters in the steam piping where the steam flows and attaching a pressure sensor or temperature sensor that detects the pressure or temperature of the steam. A volumetric flow meter that detects the volumetric flow rate of the steam and a mass flowmeter that detects the mass flow rate of the flowing-down steam are arranged in series, and the detected value from each flowmeter and the pressure value or temperature value of the steam From the volumetric flow rate value of the steam in the volumetric flow meter: A and the mass flow rate value of the steam in the mass flow meter: M to A / M = V from the formula V, that is, mixing of steam and water-drop condensate The specific volume of the fluid is obtained, and further, the specific volume of saturated water is V1, the specific volume of saturated steam is V2, and the dryness of steam is X, based on the relational expression V = V1 + X (V2−V1). , calculated dryness fraction or wetness of the steam flowing down Dryness measuring device of the steam, characterized by comprising a that arithmetic control unit.

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