JPS60105920A - Supply water amount measuring apparatus - Google Patents

Abstract

PURPOSE:In dispense with a thermostatic chamber, by providing a calculator having a means for correcting the output of a supply water transmitter corresponding to the output of an open air temp. sensor and a means for operating a supply water flow amount from the corrected value and the output of a supply water temp. sensor. CONSTITUTION:The output value of a transmitter 1 is read in a calculator 3 from a process input/output apparatus 2 while the value of an open air temp. sensor 6 is read in the calculator 3 from the input/output apparatus 2. If there is no shift between the read temp. and a reference temp., the value of the transmitter 1 is outputted as it is while converted to a flow amount value and, if there is shift over a predetermined value or more, the shift with a proper temp. value is calculated and correcting calculation is performed on the basis of an experimentally calculated correction formula and the corrected value is outputted after converted to a flow amount. By this method, the transmitter can be provided without using a thermostatic chamber and maintenance can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a water supply flow rate measuring device used in a supervisory control computer system.

[Technical background of the invention and its problems]

In nuclear power plants, changes in the feed water flow rate have a large effect on burnup and electrical output, and accurate measurement of the feed water flow rate is an important issue.

Water is pressurized because it has to overcome the pressure inside the reactor to supply water to the reactor. In order to precisely measure the water supply flow rate, the temperature and differential pressure of the fluid flowing through the pipes are measured, the density of the fluid is calculated, and corrections are made for thermal expansion of the flow orifice due to temperature.

By the way, the characteristics of the water supply transmitter vary greatly depending on the outside temperature, and the error with the output calibrated at a certain reference temperature of the water supply transmitter becomes large.
It is placed in a constant temperature bath for constant temperature.

As a result, maintenance work becomes difficult, such as removing soot from the constant temperature chamber during maintenance.Furthermore, the constant temperature chamber itself often breaks down, posing a problem in plant maintenance management.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water supply flow rate measuring device that can accurately measure the flow rate of water supply without placing a flow rate transmitter in a constant temperature bath.

[Summary of the invention]

The present invention detects the outside air temperature of a flow rate transmitter with an external temperature sensor, inputs it to a computer using a process input/output device, and corrects the input value by taking into account changes in characteristics due to the temperature of the flow rate transmitter, and adjusts the temperature of the input value for the flow of fluid flowing through one pipe. The feature is that the differential pressure, that is, the flow rate can be adjusted correctly.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings.

Figure 1 shows a conceptual diagram of the water supply flow rate measuring device.
is the transmitter, and 2 is the process personnel equipment (hereinafter referred to as PI).
3 is a computer, 4 is an output device, 5 is a fluid temperature sensor, 6 is a transmitter outside air temperature sensor, and 7 is a storage unit.

With this configuration, temperature correction of the transmitter 1 is performed in accordance with the procedure shown in FIG. That is, the output value of the transmitter 1 is read into the computer 3 from the P-engine 10 device 2 (A), and is stored in the storage section 7. Next, read the value of the transmitter ambient outside air temperature sensor 6 from the PI10 device 2 to the computer 3 (
B). If there is no difference between the read temperature and the reference temperature (c), the value of the transmitter 1 is directly converted into a flow rate value and output (step).

However, if there is a deviation of more than a predetermined value between the outside air temperature surrounding the transmitter and the reference temperature (c), the deviation from the appropriate temperature range of the reference temperature range stored in advance is calculated.

Next, a correction calculation is performed (e), and the flow rate is converted and output (f).

For example, if the appropriate temperature range is TI <T
l, and the transmitter input storage value is 3'o (m
mHg), when Tt < To < Tz,
When the temperature is within the appropriate temperature range, the stored value '10 is converted to a flow rate value and then output.Ts>To or 'ro
>Tt, the correction value to be added to the temperature measurement value in the case of temperature difference Δ'r='ro -TI is determined by the function f(ΔT), then the output value y is y=31o+f(
ΔT), which is output from the computer after converting the value of y into a flow rate value. However, here, f(ΔT) is an inverse function of the transmitter output voltage e=e(ΔR(T)). Basically, it can be explained as follows.

That is, in order to calculate the correction value f(ΔT), for example, the water supply transmitter should have a structure as shown in FIG. The resistance value of the sensor 12 is changed.

The change in resistance value of the differential pressure sensor 12 is detected by the bridge circuit 13 in FIG. 4, amplified by the amplifier 14, and output as a differential pressure. Note that 15 in FIG. 4 indicates a power source.

In this case, the resistance R of the differential pressure sensor 12 changes depending on the temperature T as shown in FIG. Based on the data and the reference output value, calculate the correction value f(ΔT). For example, when f(ΔT) is approximated by a polygonal line as a linear function of temperature, the output data when changing the environmental temperature close to the transformer Z ivy input data is 01, the temperature at that time'! If the rTAx reference output value is 02, the temperature at that time is T1zF, and the temperature at the time of transmitter input data measurement is To, then the correction value f(ΔT) is 1) T'
1>ToS or T6) If Tt then It) To <
When To < Tt, f(ΔT)=0.

By detecting the environmental temperature and correcting the output value of the transmitter 1 in this way, even if the outside temperature changes significantly, the transmitter 1 can be installed without a constant temperature bath. will improve. In addition, by inputting processes such as sensor outside air temperature, differential pressure, and fluid temperature into the computer side, temperature correction can be realized without complicating the sensor structure, improving maintainability and speed.
- Significant advantages can be obtained on the sfactoractor.

Moreover, measures to deal with changes in the correction amount over time can be easily handled by simply changing the stored correction amount.

Incidentally, instead of the pI device 2 and the divider 3 in the above embodiment, a φ converter 20 and a microcomputer 30 may be used as shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, since the feed water transmitter output is temperature-compensated, it is possible to measure the feed water flow rate with high precision without placing the transmitter in a constant temperature bath as in the past. The effect is that the maintenance and inspection work of the transmitter becomes easier.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of a water supply flow rate measuring device according to an embodiment of the present invention, FIG. 2 is an operation flowchart of FIG. 1,
Figure 3 is a structural sectional view of the transmitter in Figure 1, Figure 4 is a circuit diagram of the transmitter in Figure 1, and Figure 5 is a cross-sectional view of the transmitter in Figure 1.
FIG. 6 is a temperature characteristic diagram of the differential pressure sensor shown in FIG. 6, and FIG. 6 is a block configuration diagram of a water supply flow rate measuring device according to another embodiment of the present invention. l...Transmitter, 2...Process staffing device,
3... Calculator, 4... Output device, 5... Fluid temperature sensor, 6... Transmitter outside air temperature sensor,
7...Memory section. Figure 1 6 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] A water supply transmitter, an outside air temperature sensor that measures the ambient outside air temperature at a location where the water supply transmitter is installed, a water supply temperature sensor that measures the temperature of the water supply, and means for correcting the transmitter output according to the output of the outside air temperature sensor, and correction thereof. A water supply flow rate measuring device comprising: a calculator having means for calculating the water supply flow rate from the calculated value and the output of the water supply temperature sensor.