JPS5937455B2 - Flow rate difference detection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a flow rate difference detection device used for monitoring, for example, leakage of cooling water from a blast furnace tuyere.

The tuyere of a blast furnace is cooled and protected from burnout by a large amount of freshwater or seawater, but if cooling water leaks into the furnace, it may lead to a major accident and cause significant damage. It will be done.

For this reason, monitoring of cooling water leakage at the blast furnace tuyeres has become essential. Recently, water leakage has been monitored by using a flow rate difference detection device to detect the difference between the flow rate on the inflow side and the flow rate on the outflow side of the tuyere. In this case, the reliability of the measuring equipment that makes up the device is extremely important;
No matter how reliable a measuring instrument is, it is affected by various types of fluid noise, and may generate erroneous signals due to shifts in the zero point or variations in span. Therefore, if the measurement equipment can be quickly calibrated when a flow rate difference signal is detected, the reliability of the device will be further improved. In order to achieve such an object, the present invention provides a flow rate difference detection device that is provided with a means for quickly calibrating a measuring device. FIG. 1 is a block diagram showing one embodiment of the apparatus of the present invention.

In the figure, A is a monitored device such as a blast furnace tuyere, P is a fluid inflow path to the monitored device A, P2 is a fluid outflow path, P3 is a bypass path on the fluid inflow side, and P4 is an outflow path. side bypass path, P5 is a bypass path provided in parallel with the monitored device A, V1, V,' are valves provided in the inflow path P, V2, V2' are valves provided in the outflow path P2,
V3, V4, and V5 are bypass paths P3, P4, and P, respectively.
5, F1 is a flow rate detector provided in the inflow path P, and F2 is a flow rate detector provided in the outflow path P2. For example, electromagnetic flowmeters are used as the flow rate detectors F1 and F2c. OP is an arithmetic unit that calculates the difference between the outputs of the flow rate detectors F4 and F2, and constitutes a flow rate difference detector F with the flow rate detectors F7 and F2. In the device of the present invention configured in this way, in normal measurement conditions, the valves V,,V,,V,
is closed, valves 1, V1', V2, and V2' are opened, the flow rate Q1 in the inflow path P1 of the fluid to the monitored device A is detected by the flow rate detector F1, and the flow rate Q2 in the outflow path P is detected.
is detected by the flow rate detector F2, and converted into a signal ΔQ proportional to the flow rate difference (Q1-Q2) by the arithmetic unit 0P.

This flow rate difference signal ΔQ becomes zero if there is no water leakage in the device A to be monitored. Therefore, by monitoring the flow rate difference signal ΔQ, it is possible to detect whether water leakage has occurred in the monitored device A. However, the flow rate difference signal ΔQ obtained in this way
In order to ensure that this always occurs due to water leakage from the monitored device A, it is necessary to calibrate the flow rate difference detector F. Therefore, in the present invention, when the flow rate difference signal ΔQ occurs, first the valve Vl
, Vl', V2, V2' are closed and the flow rate detectors Fl, F2 are
Reduce the flow rate to zero. At this time, the zero point can be checked depending on whether the output of the flow rate difference detector F is zero, and if the output of the flow rate difference detector F is generated, either flow rate detector Fl or F2 is detected. The zero point of one (for example, F2) is adjusted so that the output of the flow rate difference detector F becomes zero. At this time, if the valves V, , V are left open, the zero point can be checked and adjusted without stopping the fluid supply to the device A to be monitored. Next, valves 1' and V2' are kept closed, and valves Vl and V2' are kept closed.
V2, V are opened and equal flow rates are supplied to the flow rate detectors Fl, F2 via the bypass path P5.

Therefore, a punch check can be performed depending on whether the output of the flow rate difference detector F is zero or not, and if the output of the flow rate difference detector F is generated, one of the flow rate detectors Fl and F2 (
For example, the span of F2) is adjusted so that the output of the flow rate difference detector F becomes zero. At this time, valves V,,, are opened, and valves V,...
, the span can be checked and adjusted without stopping the fluid supply to the device A to be monitored.
As described above, according to the present invention, the zero point and span of the flow rate difference detector can be easily checked and adjusted by simply operating the valve, so that the flow rate difference detector can be quickly calibrated. In addition, in the above,
Although the case where the flow rates of the fluid inflow path and outflow path are detected by separate detectors has been exemplified, for example, as shown in FIG. 2, a flow rate difference detector F housed in the same case may be used. Further, although an electromagnetic flowmeter is exemplified as a flow rate detector, other flow rate detectors such as a Karman vortex flowmeter can be used as necessary. Note that during calibration, as shown in Figure 3, the fluid supply to the flow rate detectors Fl and F2 and the fluid supply to the monitored device A may be separated; If the supply is not required, the bypass paths P, , P, can be omitted as shown in FIG. As explained above, in the present invention, valves are provided in the inflow and outflow paths of the fluid to the monitored device, and a bypass path with a valve is provided in parallel with the monitored device, so that the detector can be detected by simply operating the valve. Since the zero point check is performed, it is possible to obtain a flow rate difference detection device in which the detector can be calibrated quickly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the apparatus of the present invention, and FIGS. 2 to 4 are block diagrams of other embodiments of the system of the present invention. A...Monitored device, Fl, F2...Flow rate detector,
P1...Inflow path, P2...Outflow path, P, ~P5...
・Bypass path, 1 to V5, l', V2t...valve,
0P...Calculator, F...Flow rate difference detector.

Claims (1)

[Claims] 1 In a device that detects the difference between the flow rate on the inflow side and the flow rate on the outflow side by providing flow rate detectors F_1 and F_2 in the inflow path P_1 and the outflow path P_2 of fluid to the monitoring target device A, respectively, the flow rate of the inflow path P_1 Detector F_1
Valve V_1 is provided on the input side of the valve and closes when checking the zero point.
and a valve V_1' provided on the output side of the flow rate detector F_1 and closed during zero point and span checks, and a valve V_1' provided on the input side of the flow rate sensor F_2 of the outflow path P_2 and closed during zero point and span checks. The flow path consisting of the valve V'_2, the valve V_2 provided on the output side of the flow rate detector F_2 and closed during zero point check, the valve V'_1, the monitored device A, and the valve V_2' are parallel. Bypass path P_
5 and a valve V_5 which is closed during measurement,
A flow rate difference detection device characterized in that by operating these valves, the flow rate to both flow rate detectors F_1 and F_2 is made zero during a zero point check, and the flow rate to both flow rate detectors F_1 and F_2 is equalized during a span check.