JPH06221983A - Wetness measuring device - Google Patents

Abstract

PURPOSE:To make it possible to perform measurement in a broad range by providing flowmeters in a steam separator, whose steam separating efficiency is known. CONSTITUTION:A steam separator 2 is attached to a steam pipe 1. Flowmeters 3 and 4 are arranged at the input side and the output side of the steam separator 2. The flowmeters 3 and 4 and an operating part 5 are connected. The separating efficiency of the steam separator 2 can be expressed as the ratio between the amount of water content, which is drained to the outside of the system from the steam separator 2 and the amount of water content flowing into the steam separator 2. The amount of the water content, which is discharged to the outside of the system from the steam separator 2 can be converted with the flow-rate values, which are measured with the flowmeters 3 and 4 provided at the input side and the output side of the steam separator 2. The amount of the water content flowing into the steam separator 2 can be detected with the product of the flow-rate value of the flowmeter 3 on the input side of the steam separator 2 and a dryness X. Therefore, the dryness X can be obtained with this relationship when the separating efficiency of the steam and water is known beforehand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the wetness of steam or the like flowing through a gas pipe. In various boilers and equipment utilizing steam power, the moisture content in the steam, that is, the dryness X indicating the ratio of the mass occupied by the dry saturated steam to the total mass per unit volume of the steam flow, or the wetness (1-
X) needs to be known. This is because the enthalpy of steam differs depending on the water content.

[0002]

2. Description of the Related Art A conventional wetness or dryness measuring device for steam is a squeezing dryness meter. In this method, the wet steam to be measured is injected through a nozzle into a measuring container equipped with a thermometer and a pressure gauge for adiabatic expansion to bring it into a superheated steam state and measure the wetness. As another wetness measuring device, the measured wet steam is flowed in the inner pipe of the double pipe,
There is a method in which the same amount of superheated steam is caused to flow in the outer pipe, the wet steam is heated by this superheated steam flow to be converted into superheated steam, and the measured steam is sampled to measure the wetness.

[0003]

SUMMARY OF THE INVENTION In the former case described above,
There is a problem that the range of wet steam that can be measured is limited. That is, when the pressure of the steam is low, it is necessary to make the pressure very low in order to bring it into the superheated steam state in the container, and when the steam has a high degree of wetness, it does not become the superheated steam state after expansion. is there. Further, the latter one requires superheated steam as a heating source, and it is practically difficult to flow the same amount of superheated steam as the measured wet steam and to sample the measured wet steam. Therefore, the technical problem of the present invention is to provide a wide range of measurable wetness and to easily measure the wetness.

[0004]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problems is to separate water in a gas, and to separate the water from the water. And a flow meter for measuring the amount of fluid at the inlet side and the outlet side of the steam-water separator are provided, and the wetness is calculated based on the separation efficiency of the steam-water separator and the flow rate value measured by both flow meters. The calculation unit is provided.

[0005]

The operation of the above technical means is as follows.
The separation efficiency of the steam separator is expressed as the ratio of the amount of water discharged from the steam separator to the outside of the system and the amount of water flowing into the steam separator. Then, the amount of water discharged from the steam separator to the outside of the system can be converted by the difference between the flow rate values measured by the flowmeters installed on the inlet side and the outlet side of the steam separator. The amount of water flowing in can be detected by the product of the flow rate value of the flow meter on the inlet side of the steam separator and the dryness X. Therefore, if the separation efficiency of air and water is known in advance, the dryness X can be obtained from these relationships.

[0006]

EXAMPLE An example showing a concrete example of the above technical means will be described (see FIG. 1). In this embodiment, an example of an apparatus for measuring the wetness or dryness of steam, which is widely used as a heat source in various factories and plants, is shown. Attach the steam separator 2 to the steam pipe 1. A flow meter 3 is arranged on the inlet side of the steam separator 2 and a flow meter 4 is arranged also on the outlet side. The flow meters 3 and 4 are connected to the calculation unit 5. Further, a steam trap 6 for discharging drainage as condensed water in the steam pipe 1 is attached, and a discharge pipe 7 for discharging separated water to the outside of the system is connected to the steam separator 2. Although not shown, the steam separator 2 has a steam trap function of discharging only the separated water to the discharge pipe 7.

As the flowmeters 3 and 4, well-known ones such as a vortex type, a differential pressure type, a hot wire type, a flapper type, an ultrasonic type and a Coriolis type can be used. In the present embodiment, the vortex type flowmeter is used. An example using is shown. Further, as the steam separator, a well-known separator such as a swirl type, a collision type or a filter type utilizing centrifugal force can be used.

The drain located under the steam flowing in the steam pipe 1 is discharged to the outside of the system by the steam trap 6. However, the steam contains a minute amount of water-like drain as water, and the wetness of the steam changes depending on the amount of this water.

The vortex flowmeters 3 and 4 can measure the volumetric flow rate of steam, and can be converted into the mass flowrate by multiplying the volumetric flow rate by the specific weight of steam.
When the dryness is X, the specific weight of steam: r is r = r1
It can be represented by xr2 / {X * r1 + (1-X) * r2}. In this case, r1 is the specific weight of saturated water, and r1
2 is the specific weight of dry saturated steam, which can be read from the steam table.

Assuming that the volumetric flow rate of steam measured by the flow meter 3 is Q1, the dryness of steam is X1, and the mass flow rate is W1,
W1 = r1 × r2 × Q1 / {X1 × r1 + (1-X1)
Xr2} holds, and if the volumetric flow rate of the steam measured by the flow meter 4 is Q2, the dryness of the steam is X2, and the mass flow rate is W2, then W2 = r1 × r2 × Q2 / {X2
The relational expression xr1 + (1-X2) xr2} holds.
Since the separation efficiency of the steam separator 2 can be expressed by the ratio of the amount of water discharged to the outside of the system and the amount of water flowing in, the separation efficiency: K is K = (W1−W2) / {W1 × (1-X
1)}. Furthermore, since the moisture that has not been separated by the steam separator 2 is measured as the mass flow rate by the flowmeter 4 on the outlet side, W1 × (1-X1) × (1-
The relational expression K) = W2 × (1−X2) holds. Of these four relational expressions, Q1 and Q2 can be measured by the flowmeters 3 and 4, and r1 and r2 can be read from the steam table, so they must be stored in the calculation unit 5 or input. It turns out by. Therefore, if the separation efficiency: K of the steam separator 2 is known in advance, the unknowns X1, X
The drynesses X1 and X2 can be calculated by solving the above four relational expressions for 2, W1 and W2 in the calculation unit 5.

In this embodiment, the drynesses X1 and X of the vapors passing through the flowmeters 3 and 4 are vortex type flowmeters.
Although an example of a dryness or wetness measuring device capable of calculating 2 has been shown, by using a mass flowmeter for the flowmeters 3 and 4, the separation efficiency: K flows into the steam separator 2 from the relational expression. The dryness of steam: X1 can be calculated. In this embodiment, the steam / water separator 2 has a steam trap function for discharging only the drain, but the separator and the drain discharge valve may be separately arranged, or When the drain amount is small, a drain reservoir can be provided instead of the drain discharge valve.

[0012]

The present invention produces the following unique effects. As described above, according to the present invention, a gas containing water is brought into an overheated state, or superheated steam is not required, so that the measurable wetness range is widened and the dryness or wetness can be easily measured. it can. Further, since the flow rate flowing through the gas pipe can be known, it is possible to obtain data for improving the operating efficiency of the equipment connected to the gas pipe and judging the abnormality of the gas pipe.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a wetness measuring apparatus of the present invention.

[Explanation of symbols]

 1 Steam piping 2 Steam separator 3 Inlet side flow meter 4 Outlet side flow meter 5 Computational unit 6 Steam trap 7 Discharge pipe

Claims (1)

[Claims] 1. A steam separator for separating moisture in a gas, the separation efficiency of which is known in advance, and a flow meter for measuring the amount of fluid at the inlet side and the outlet side of the steam separator. A wetness degree measuring device provided with a calculation unit for calculating the wetness degree based on the separation efficiency of the steam separator and the flow rate values measured by the both flowmeters.