JPS5925177B2 - Soutai Shitsudokei - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a relative humidity meter that obtains relative humidity from signals corresponding to a basket bulb temperature and a wet bulb temperature, respectively.

By utilizing the fact that the relative humidity ψ has a predetermined relationship with the temperature difference 5 (5=Td-Tw) between the basket bulb temperature Td and the wet bulb temperature Tw, the basket bulb temperature Td and the wet bulb temperature Circuits have already been proposed that calculate relative humidity from signals corresponding to Tw using various calculation means.

However, although the Td-Tw characteristic is approximated to a straight line, it is not a straight line, so in the conventional method of calculating on the assumption that this relationship is a straight line, even if there are no errors due to other causes, The relative humidity values obtained are only approximations and inherently contain errors. The purpose of this invention is to create a function corresponding to the relationship between temperature difference S and relative humidity ψ, and to perform calculations using this function to obtain a relative humidity value with higher accuracy. The aim is to provide a measurement system.

An embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a detection terminal such as a temperature measuring resistor that detects the wet bulb temperature Tw and 2 detects the basket bulb temperature Td and generates a corresponding electric signal. The output of detection end 1 is
It is used by the preamplifier 3 to generate a voltage Ew corresponding to the wet bulb temperature, and a voltage Ed is likewise obtained from the output of the detection terminal 2 by the preamplifier 4. The voltages Ew and Ed are expressed by the following equations. Ew=aTw+b Ed=aTd+b (where a and b are constants) The outputs of preamplifiers 3 and 4 are input to a subtracter 5 including an operational amplifier, where Ed-Ew=a(Td-Tw)
An operation expressed as =a5=Es is performed.

This voltage Es is supplied to one input terminal Z of the divider 10 and at the same time to the other input terminal X via the resistor R2. On the other hand, the voltage Ed is also supplied to the input terminal X via the resistor R1, and is input as the voltage Ex to the human power terminal x of the multiplier 6, which has a large input impedance. The voltage Ex is expressed as Ex=-Ed+Es R1+R2R1+R2 If we do this, the above equation becomes as follows〇Ex=KlE
d+K2Es Multiplier 6 calculates Iz=CExEy (where c is a constant) as a current 1z proportional to the product of voltages Ex and Ey from output terminal Z when voltages Ex and Ey are applied to input terminals X and y, respectively. The output voltage Ey of the 0 operational amplifier 7 is configured to send out a signal, and its output terminal Z is connected to the inverting input of the operational amplifier 7. Since the output voltage Ey of the operational amplifier 7 is negatively fed back via the multiplier 6, it can be used as the operational amplifier 7. By using one with high input impedance and high amplification, i.e. 0, the divider 10 has voltages Ex and E at inputs X and Z, respectively.
When z is applied, it operates to generate a voltage at the output terminal Y.

Output voltage Ey of divider 10 and voltage −E from DC power supply 9
a is manually input to the operational amplifier 8 via a resistor, and its output is EO=Ey-(-Ea) =Ea+Ey. This equation has the form, and the constants K, Kl, K2, K3 can be arbitrarily determined by appropriately selecting circuit constants such as voltage Ea and resistors Rl, R2, R3. Figure 2 shows the relationship between temperature difference S and relative humidity ψ at each dry bulb temperature Td. It shows the correspondence between a curve determined in advance regarding the relationship and an actually obtained output voltage EO.

Note that the constant in equation (1) is 0K = 1, which is determined as follows.
0 K1= 0.3 K2= 4.5 K3= 0.31 As is clear from Figure 2, ψ=30~100%, Td
= Obtained output EO over a wide range of 5 to 60°C
The value of is in good agreement with the relative humidity ψ〇

[Brief explanation of the drawing]

Claims (1)

[Claims] 1. A relative hygrometer having a first element whose electrical properties change in response to atmospheric temperature and a second element whose electrical properties change in response to the amount of water vapor contained in the atmosphere. , one input terminal receives a voltage signal (Ed
) and the voltage signal (Ew) corresponding to the above amount of water vapor (
A voltage (Ez) proportional to Es) is used at the other input terminal, and a voltage (Ex) proportional to k_1Ed+k_2Es (k_1 and k_2 are coefficients) is used at the other input terminal, and Ex/E
A relative hygrometer comprising a divider circuit for dividing z, and configured to measure relative humidity using the output voltage of the divider circuit.