JPS5999240A - Device for measuring moisture - Google Patents

Abstract

PURPOSE:To improve the performance in measurement with a simple operation by calculating the signals from two detectors, which detect the oxygen concn. in gas before and behind a dehumidifier, in an arithmetic circuit having a delay circuit. CONSTITUTION:The 1st oxygen concn. detector 15 measuring the concn. of the gas in a furnace wall 16 transmits a concn. signal Z1 of the oxygen in the state contg. moisture, then the 2nd oxygen concn. detector 20 measuring the gas dehumidified with a dehumidifier 18 transmits a concn. signal Z2 in the state contg. no moisture. The signal Z1 is introduced into an arithmetic circuit with a delay by the delay time when the measuring gas arrives from the detector 15 at the detector 20 in a delay circuit 13. Said circuit calculates the concn. of the moisture in the gas from the signals Z1, Z2. The selection of the delay time is thus possible from the flow rate of the measuring gas and the capacity of the dehumidifier 18 and since the selection of a constant for the delay circuit is easy, the performance in measurement is improved by the simple operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling the oxygen concentration in a gas containing moisture;
The present invention relates to a moisture measuring device that measures moisture by determining the difference between the oxygen concentration in the gas after moisture has been removed.

FIG. 1 shows a schematic configuration diagram of a moisture measuring device that has already been filed by the applicant of the present invention. In the figure, it consists of a hot air dryer, a drying container 2, a blower 3, a burner 4 that burns gas or oil, and the like.

Air is blown by the blower 3, and this air is heated by the burner 4 and sent to the drying container, and the material to be dried 5 in the drying container 2 is heated.
After drying, exhaust. At this time, an inlet oxygen concentration detector 6g and an outlet oxygen concentration detector 7 are placed at the inlet and outlet of the drying container 20 to detect the inlet oxygen concentration z1 and the outlet oxygen concentration z2, respectively. This inlet and outlet oxygen concentration detector 6゜7 has an inlet? and outlet oxygen concentration Z 1
A fixed electrolytic oxygen concentration detector capable of measuring +22 at a temperature equal to or higher than the dew point temperature, such as a known zirconia oxygen concentration detector, is used. The outputs of the oxygen concentration detectors 6 and 7 are amplified by amplifiers 8 and 9, respectively.

By the way, the inlet oxygen concentration z1 in the heated gas is not necessarily constant and may vary over time. For this purpose, the oxygen concentration z detected by the inlet oxygen concentration detector 6
1 for the heated gas to pass between the inlet and outlet oxygen concentration detectors 6 and 7 before it passes through the drying container 2 and is detected by the outlet oxygen concentration detector 7 at the outlet of the drying container 2. There is a delay of transit time t. Therefore, a delay circuit 13 is connected to the amplifier 8, and by delaying the inlet oxygen concentration signal Zl by the passage time t of the heated gas, the inlet oxygen concentration signal Zl is compared with the outlet oxygen concentration signal z2, and the output from the division circuit 11 and the subtraction circuit 12 is The water concentration y is calculated by the arithmetic circuit 10.

However, according to this method, the oxygen concentration detector 6.7 must be installed at a location separate from the inlet and outlet of the drying container 20. Further, the flow rate of the heated gas flowing through the drying container 2 changes depending on the operating conditions. Therefore, there is a problem in that accurate measurements cannot be obtained unless the delay time is changed in accordance with the transit time t each time.

In view of the above-mentioned points, it is an object of the present invention to provide a moisture measuring device that eliminates the drawbacks of the prior art, is easy to handle, and can improve measurement performance. a first oxygen concentration detector that detects the oxygen concentration and transmits an oxygen concentration signal zl in a state in which moisture is contained; and a first oxygen concentration detector that detects the oxygen concentration in the dry gas from which moisture in the measurement gas has been removed and in a state in which it does not contain moisture. a second oxygen concentration detector that transmits an oxygen concentration signal z2, a delay circuit that delays the oxygen concentration signal z1 by a delay time caused to remove moisture in the measurement gas, and a second oxygen concentration signal z2 that is delayed by the delay circuit; This is achieved by comprising a calculation circuit that calculates the water concentration y contained in the measurement gas from the oxygen concentration signal z1 and the oxygen concentration signal z2 based on a predetermined calculation formula.

Next, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 shows a schematic configuration diagram of an embodiment of the present invention.

In the figure, the first oxygen concentration detector 15 is installed, for example, on the furnace wall 16 on the rear side of the hot air dryer, and measures the gas to be measured in the furnace at a high temperature higher than the dew point temperature by directly inserting it into the gas to be measured. This is a zirconia oxygen concentration detector. This first oxygen concentration detector 15 transmits an oxygen concentration signal z1 in a state where the measurement gas contains moisture. This first oxygen concentration detector 1
The measurement gas is branched from 5 by a suction pump 19 through a connecting pipe 17 and introduced into a dehumidifier 18 to be dehumidified, and then this dehumidified gas is introduced into a sample container 21. This sample container 2
A second oxygen concentration detector 20Fi installed in the dehumidified gas 1 detects the oxygen concentration in this dehumidified gas and transmits an oxygen concentration signal z2 in a state containing no moisture.

To measure the moisture concentration y in the measurement gas using this oxygen concentration signal ZIvZ2, as shown in FIG. 3, if the volume of the measurement gas is Vo and the volume of oxygen in this measurement gas is 2, then The following formula holds true.

Further, for the & elemental concentration signal z2 detected by the second oxygen concentration detector 20, the following equation (2) holds true, assuming that the volume of water in the measurement gas is 1.

Note that the water concentration y at this time is expressed by the following equation.

Next, v2 is obtained from equation (2), substituted into equation (1), and transformed as shown in equation (5).

This equation (5) is transformed to obtain equation (6).

As is clear from this equation (6), the water concentration y is expressed by a constant relational expression with the oxygen concentration signal ratio Zl/z2, and the water concentration y can be calculated by calculating this oxygen concentration signal ratio Z1/z2. You can ask for it.

However, the oxygen concentration signal z1 transmitted by the first oxygen concentration detector 15 is delayed due to the time required for the measurement gas to reach the second oxygen concentration detector 20 from the first oxygen concentration detector 15 via the dehumidifier 18. The oxygen concentration signal z1 is delayed by the delay circuit 13 by the amount of time.

This delay causes the oxygen concentration signal z1. Z2 is synchronized,
It is introduced into the arithmetic circuit IO. In the arithmetic circuit 10, the division circuit 11 divides the oxygen concentration signal Z in the measurement gas containing moisture by the oxygen concentration signal z2 in the dehumidified gas, and then the subtraction circuit 12 divides the oxygen concentration signal Z from the constant 1. By subtracting, the accurate water concentration y is calculated.

Next, FIG. 4 shows a schematic configuration diagram of another embodiment of the present invention. Components in the figure that have the same functions as those in FIG. 2 are given the same reference numerals. A gas sampling tube 22 is inserted into the furnace wall 16 adjacent to the first oxygen concentration detector 15 . The measurement gas is introduced into the sample container 21 by the suction pump 19 through the gas sampling pipe 22, the dust removal filter 23, and the dehumidifier 18.

A second oxygen concentration detector 20 installed in this sample container 21
detects the oxygen concentration in the dehumidified gas and transmits an oxygen concentration signal Z2. Therefore, similarly to FIG. 2, the time delay required for the measurement gas to reach the second oxygen concentration detector 20 from the gas sampling pipe 22, through the dust removal filter 23, and the dehumidifier 18, causes the first oxygen concentration detector 15 to The oxygen concentration signal Zl is delayed by the delay circuit 13. Due to this delay, the oxygen concentration signal Zl+Z2 is synchronized, and is therefore inputted to the arithmetic circuit 10 to calculate the water concentration y. Although it is desirable that the first oxygen concentration detector 15 and the gas sampling tube 22 be installed as close together as possible, even if they are separated, the gas sampling tube 22 is connected to the first oxygen concentration transmitter 15 so that the measurement gas flow is It is preferable to place it on the upstream side of the system to reduce the delay time.

As described above, according to the present invention, the first oxygen concentration detector detects the oxygen concentration of the high-temperature measurement gas and transmits the m-line concentration signal Z1 containing moisture; a second oxygen concentration detector that detects the oxygen concentration in the removed dehumidified gas and transmits an oxygen concentration signal z2 in a state that does not contain moisture; The oxygen concentration signal z1 is
Conventionally, oxygen concentration detectors were installed at the inlet and outlet of the drying container, the delay time between these points was measured, and the constant of the delay circuit was calculated based on this measured value. Due to the complexity of handling operations for determining
By determining the flow rate of the measurement gas introduced into the second oxygen concentration detector and the capacity of the dehumidifier, sample container, etc., it is possible to select the delay time, and the constants of the delay circuit can be easily selected, making it easy to handle and operate. At the same time, it has advantages such as improved measurement performance.

By adding a dehumidifier, the present invention can be applied not only to a drying container such as the heating dryer described above (as an example), but also to a wide range of general applications for measuring moisture in exhaust gas. Of course.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the moisture measuring device that has already been proposed.
FIG. 2 is a schematic block diagram of one embodiment of the present invention, FIG. 3 is a diagram explaining the principle of water concentration measurement, and FIG. 4 is a schematic block diagram of another embodiment of the present invention. 10: Arithmetic circuit, 11: Division circuit, 12: Subtraction circuit, 1
3: delay circuit, 15: first oxygen concentration detector, 18: dehumidifier, 2o: second oxygen concentration detector, 21: sample container. Patent applicant Fuji Electric Manufacturing Co., Ltd. ■0 3rd Tm Figure 4

Claims (1)

[Claims] (1) A first oxygen concentration detector that detects the oxygen concentration in the measurement gas at a temperature equal to or higher than the dew point temperature and transmits an oxygen concentration signal z1 in a state in which moisture is contained; a second oxygen concentration detector that detects the oxygen concentration in the dehumidified gas and transmits an oxygen concentration signal z2 in a state that does not contain moisture; a delay circuit that delays z1, and a calculation that calculates the moisture concentration y contained in the measurement gas based on a predetermined calculation formula from the oxygen concentration signal zl and the oxygen concentration signal z2 delayed by the delay circuit. A moisture measuring device characterized by comprising a circuit.