JPS60133323A - Infrared-ray analyzer - Google Patents

Abstract

PURPOSE:To perform highly accurate analysis, by providing a fixing plate having slits, providing a movable plate, which is supported by two points on a straight line passing the center of gravity and can be rotated, detecting the difference in pressures, thereby making it hard to receive the effect of vibration noises and posture change. CONSTITUTION:Infrared rays, which have passed a sample cell 1 and a comparing cell 2, are inputted to light receiving chambers 51 and 52, and pressures P1 and P2 are generated. Said pressures P1 and P2 are supplied to a pressure measuring means 6, and the pressure difference P1-P2 is detected. The measuring means 6 is provided with a fixed plate 70 having slit holes and a movable plate 92, which is arranged so as to face the fixed plate and supported by a supporting port 93 at two points on a straight line passing the center of gravity. In this constitution, the movable plate 92 is slanted by an angle proportional to the pressure difference P1-P2. The displacement of the movable plate 92 is measured as the change in electrostatic capacity. Thus the difference between the pressures P1 and P2 can be detected. Since such a pressure measuring means is hardly affected by vibration noises and attitude change, highly accurate analysis can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an infrared analysis needle that analyzes the concentration of various gases by utilizing absorption characteristics in the infrared wavelength range. More specifically, the present invention allows infrared light flux from a light source to enter the gas to be measured, and also directs the infrared light flux that has passed through the gas to be measured into a part that absorbs infrared rays and expands. This invention relates to an infrared analyzer that can determine the concentration of a gas to be measured by measuring the pressure generated in the gas.

[Description of prior art]

FIG. 1 is a sectional view showing an example of a conventional infrared analysis needle of this type. This infrared analyzer consists of a measurement cell 1 through which a gas to be measured flows continuously, a comparison cell 2 filled with an inert gas (for example), a collar 5, and a condenser microphone type infrared ray filled with measurement gas components. a detection unit 6; an amplification unit 61 that amplifies the detection signal of the infrared detection unit 6;
It consists of an instruction recording section 62, a trimmer 35 that adjusts the amount of light from the measurement cell 1 side, and a trimmer 36 that adjusts the amount of light from the comparison cell 2 side.

This kind of crab beam infrared analyzer is affected by fluctuations in the power source of the light source (normally, light sources 5 and 4 are powered by the same power source) and by the atmospheric gas at the location where the analyzer is installed (comparison cell 2 is Otherwise, it will be affected by moisture in the air)
It has the characteristics of reducing the amount of water and providing stable characteristics.

However, in such conventional devices.

A condenser microphone is used as the infrared detection section 6, and this condenser microphone is composed of a metal film that receives pressure and a fixed electrode placed opposite to this metal film.The metal film detects the displacement of the metal film due to pressure. This method detects changes in capacitance between a fixed electrode and a fixed electrode, and there is a problem in that the entire surface is covered with a metal film. Furthermore, since the detection sensitivity is high, there is a drawback that it is easily affected by vibration noise and changes in posture.

For this reason, if the device was installed in a place with vibrations or in a non-horizontal place, highly accurate analysis could not be performed.

[Object of the present invention]

The present invention has been made in view of these drawbacks of conventional devices, and aims to realize an infrared analyzer that has a simple configuration and is less susceptible to vibration noise and changes in posture.

[Summary of the invention]

The present invention provides an apparatus for analyzing the concentration of a gas to be measured using absorption characteristics at an infrared wavelength range, and a fixed plate having a slit hole therein as a means for measuring the pressure generated in relation to the concentration of the gas to be measured. A movable plate that is placed opposite the fixed plate and applies the pressure to be measured, a support that supports the movable plate at two points on a straight line passing through the center of gravity so that the movable plate can rotate, and the displacement of the movable plate. It is characterized in that it uses a detection means for detecting torque.

〔Example〕

FIG. 2 is a sectional view showing an example of a device according to the present invention. In this figure, 1 is a measurement cell into which the gas to be measured is introduced, 2 is a comparison cell filled with a reference gas such as ijN, and 3 is a comparison cell filled with a reference gas such as ijN.
is an infrared light source, and infrared light from this is reflected by the concave mirror 3O and enters the measurement cell 1 and comparison cell 2. 5 is measured as 1. The light transmitted through the comparison cell 2 is intermittent at regular intervals, and as in the device shown in Fig. It is filled with gas that absorbs infrared energy and expands.

6 is a pressure measuring means for detecting the difference in pressure generated in the light receiving chambers 51 and 52, and the pressures P□ and p2 are measured through pipes 53 and 54.
FIG. 4 is a cross-sectional view showing an example of the step 6, FIG. 4 is a perspective view of a main part showing a part in cross-section, and FIG. 5 is an assembled view of the main part. In these figures, 60 is a container, and 61 and 62 are partition walls that partition the inside of this container into two parts. Pressure introduction holes 63 and 64 are provided in each of the rooms 6a and 6b partitioned by partition walls 61 and 62.
The pressure P to be measured generated in the light receiving chamber 51 and 52 from
p2 has been introduced.

This is a pressure detection unit manufactured by Company 7, and is composed of a fixed plate 70 fixed to partition walls 61 and 62, and a movable part 9 disposed opposite to the fixed plate 10 with a spacer 8 interposed therebetween.

The fixed plate 70 is provided with a plurality of slits (here, five slits) 71 for guiding the pressure in the chamber 6b. The movable part 9 includes a frame 91 and a movable plate 92 supported by the frame 91 via a support part 93 and installed to face the fixed plate 70. A plurality of slits (here, five slits) 94 are provided in positions not facing the plurality of slits and the door 1 on the fixed plate 7O. Here, the movable plate 92
The support part 93c that supports the movable plate also functions as a spring, and in order to allow the movable plate to rotate, a straight line passing through the center of gravity P of the movable plate 92 (see Fig. 5) is connected to the upper two points of the movable plate. 92 is supported.

Note that in this example, the movable plate 92 has two supporting parts 93.
It is provided only on the left side with respect to the straight line t (corresponding to the rotation axis) K connecting the two.

75 is an electrode plate provided on the fixed plate 7O, and 76 is an electrode plate provided on the movable plate 92 opposite to the electrode plate 75, and these constitute displacement detection means for the movable plate 92.

The operation of the pressure measuring means 6 constructed in this way will be explained next. When the pressures p□ and P2 generated in the light receiving chambers 51 and 52 are equal, and therefore the pressures in the chambers 6a and 6b are equal, the movable plate 92 is spaced from the fixed plate 70 by a small distance equal to the thickness of the spacer 8. d is maintained.

When the force introduction holes 64 are introduced into the chambers 6a and 6b, respectively, the pressure p2 in the chamber 6b passes through the plurality of slit holes 71 provided in the fixed plate 7o as shown by the arrows, and the pressure p2 in the chamber 6b passes through the plurality of slit holes 71 provided in the fixed plate 7o as shown by the arrows, and the force is transferred to the movable plate 9.
It is added to the back side of one side without the slit hole of No.2. Also.

The pressure p□ in the chamber 6a is applied to the entire surface of the movable plate 92, and is also applied to the rear surface of one side of the movable plate 92 through the merit hole 94 where the groove hole 94 is provided. FIG. 6 shows the pressure applied to the movable plate 92 in this state.

Therefore, in the movable plate 92, the pressure between the front side and the back side through the slots and holes 94 becomes p, and no torque is generated on one side where the slots and holes 94 are provided.

On the other hand, on the other side where the slotted hole 94 is provided, pressures P1 and P2 are applied to the front side and the back side, respectively, so that a torque proportional to the difference between p□ and p2 is applied to the support part 93. join. The support portion 93 also functions as a spring, and is twisted by this torque, causing the movable plate 92 to incline by an angle corresponding to the difference between p□ and p2.

Note that the movable plate 92 is provided with slots and holes 94, and since the movable plate 92 and the frame 91 are separated, the fluid (gas) in the chambers 6a and 6b is Although it leaks through the slit holes 71 and 9
4, the gap width d□ between the movable plate 92 and the frame 91, and the distance d between the fixed plate 70 and the movable plate 92, the fluid resistance at each part is increased. 92 can be sloped to correspond to the pressure difference.

The displacement (inclination angle change) of the movable plate 92 is caused by the electrode plates 75 and 76.
This is a change in the capacitance between P and P, and by measuring this capacitance change, the pressure difference between P and P can be determined from K.

The pressure measuring means configured in this way is such that the movable plate 92 is supported at two points on a straight line passing through its center of gravity and detects the torque (or inclination of the movable plate) of the movable plate based on the pressure. Acceleration due to external vibration (translational motion component)
does not produce a force (torque) that rotates the movable plate 92, and the difference between the pressures p□ and P2 generated in the light receiving chambers 51 and 52 can be measured without being affected by vibration noise or attitude change (gravity). Therefore, the apparatus according to the present invention can perform highly accurate analysis even in places with vibrations or in non-horizontal places.

FIGS. 7 and 8 are a plan view and a sectional view of main parts showing other examples of the pressure sensing section 7 in the pressure measuring means 6. FIG.

In the embodiment shown in FIG. 7, in the movable plate 92, the rotation axis t
, on the left side 92a, t7 covers the entire surface with a plurality of (nine in this case) slots and holes 94a with the hitch p1.
92t) on the right side as well as above and below! A slit hole on the M edge! ', the same number of slit holes 94b as 4a and the same shape are formed.

The axis of rotation t can be easily taken from this movable plate 92.
can be brought to a symmetrical position.

In the embodiment shown in FIG. 8, instead of forming slots and holes in the movable plate 92, a recess 74 is formed in the fixed plate 70 on one side to the left with respect to the rotating shaft, and the movable plate and the fixed plate K is set so that the distance between the two ends is d2 (d2>d).

In this embodiment, the pressure near the recess 74 of the fixing plate 7O is close to p□ or pl because the distance d2 in this area is larger than the distance dK in other parts.
It is possible to generate torque according to the differential pressure between the movable plates 92KP1 and P2.

In each of the above embodiments, the displacement or torque of the movable plate 92 is detected as a change in capacitance between the electrodes, but other means, such as using an optical signal or using a nozzle flapper and Any method may be used to detect strain or stress in the support portion 93.

FIG. 9 shows yet another embodiment of the device according to the present invention. σ) woodknノνsutsui
In this case, the comparison cell filled with the reference gas is not included.

The infrared light source 3 is driven intermittently by a pulse circuit 30 and generates an intermittent infrared beam in two directions through infrared transmission windows 31,32. Light receiving chamber 5.1 [.

The light receiving chamber 52 receives the infrared light flux that has passed through the gas to be measured in the measurement cell 1 , and directly receives the infrared light flux that has passed through the infrared transmission window 32 . A measurement gas component that absorbs incident infrared rays and expands is sealed in each light receiving chamber 51, 52, and a pressure pp of 1' 2 corresponding to the incident infrared energy is generated in each light receiving chamber 51, 52. This pressure is applied via conduits 53, 54 to pressure measuring means 6 constructed as shown in FIG. 5, where the pressure difference within each light receiving chamber 51, 52 is detected.

The output signal of the pressure measuring means 6 is amplified by an amplifier 61 and then indicated by an indicator 62.

The basic operation of the device having such a configuration is the same as that of the conventional device. According to the device of this embodiment, since a comparison cell whose characteristics change over time is provided in the optical path, stable characteristics without zero drift can be obtained.

However, each chamber 6a of the pressure measuring means 6.

An infrared beam may be incident on 6b.

[Effects of the present invention]

As described above, according to the present invention, it is possible to realize an infrared analyzer that has a simple configuration and is less susceptible to vibration noise and posture changes.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional device, FIG. 2 is a sectional view showing an example of a device according to the present invention, and FIG. 3 is a sectional view showing an example of a device according to the present invention.
Figure 4 is a cross-sectional view showing an example of the pressure measuring means used in the device, Figure 4 is a perspective view of the main part showing a part of it in cross section, Figure 5 is an assembled configuration diagram of the main part, and Figure 6 is An explanatory diagram showing the state of the pressure applied to the movable plate in the pressure measuring means, FIGS. 7 and 8 are a plan view and a cross-sectional view of the main part showing another example of the pressure detection section, and FIG. 9 is according to the present invention. FIG. 7 is a cross-sectional view showing a configuration of yet another embodiment of the device. DESCRIPTION OF SYMBOLS 1...Measurement cell, 2...Comparison cell, 3...Infrared rays 51, 52...Light receiving chamber, 6...Pressure measuring means,
eo... Container, 70... Fixed plate, 8... Spacer, 9... Movable part, 91... Frame, 92...
Movable plate-93...Support part, 75.76...Electrode plate. Claw 7 figure JB figure Claw figure 9

Claims (1)

[Claims] (1) In an apparatus that analyzes the concentration of a gas to be measured using absorption characteristics in the infrared wavelength region, a fixed plate with slit holes and a a movable plate placed opposite to the fixed plate and to which the pressure to be measured is applied; a supporting portion supporting the movable plate at two points on a straight line passing through its center of gravity so that the movable plate can rotate; An infrared analysis needle comprising a detection means for detecting displacement or torque.