JP4428985B2 - Analyzer with self-diagnosis function - Google Patents

Description

  The present invention relates to an analysis apparatus that analyzes a sample using a detection signal (light reception signal) of a light receiving unit via the sample, and particularly enables self-diagnosis of the operation of a sample introduction member for introducing a sample into the detection unit. The present invention relates to an analyzer with a self-diagnosis function.

  FIG. 4 is a configuration diagram of a detection unit of an SS densitometer as an analyzer that measures the concentration of suspended solids (SS) in a liquid sample, and FIG. 5 is a cross-sectional view taken along line AA in FIG. It is. Here, an SS concentration meter for low concentration which has an SS concentration of 1000 ppm or less and performs measurement using transmitted light and scattered light will be described.

  In these drawings, the main body 1 is formed in a cylindrical shape having a through hole in the center, and further, accommodation holes 1a are formed in three places. The housing hole 1a communicates with the central through hole through the light emitting part window 1b, the scattered light receiving part window 1c, and the transmitted light receiving part window 1d.

The transparent measurement cell 2 is a glass cylinder and is inserted through the central through hole of the main body 1. Since the cell 2 is made of glass, light is transmitted through the light emitting portion window 1b, the scattered light receiving portion window 1c, and the transmitted light receiving portion window 1d.
The cylindrical part 3 is a cylinder made of metal and having an inner diameter and an outer diameter substantially equal to those of the transparent measurement cell 2, and is connected to the upper side of the transparent measurement cell 2 through a hermetic seal (not shown).

The piston 4 as the sample introduction member is formed in a columnar shape, and is configured to be inserted into the transparent measurement cell 2 and the cylinder of the cylinder portion 3 so as to move up and down by a lifting device (not shown).
The piston wiper part 5 is attached in the vicinity of the tip of the piston 4. When the piston 4 moves up and down, the piston wiper unit 5 moves up and down while contacting the inner peripheral surface of the transparent measurement cell 2, and algae attached to the cylinder of the transparent measurement cell 2. Clean it by scraping off the adhering substances. It also has a function to prevent air leakage.

  When the piston 4 is raised, the sample is sucked and introduced from the lower side of the through hole of the main body 1 and filled in the internal space of the transparent measurement cell 2 (hereinafter referred to as the detection unit 2a). Further, when the piston 4 is lowered, the piston 4 is lowered to the bottom dead center in FIG. 4 (indicated by a dotted line in the drawing), and the sample is discharged from the detection unit 2a to the outside.

  The light emitting unit 6 is configured by, for example, an LED (Light Emitting Diode), and irradiates the sample in the detecting unit 2a with light through the light emitting unit window 1b and the transparent measurement cell 2. As shown in FIG. 4, the lead wire 6 a connected to the light emitting unit 6 is drawn out through the lid unit 9.

  As shown in FIG. 5, the scattered light receiving unit 7 receives scattered light, which is scattered by the suspended particles among the light rays emitted from the light emitting unit 6, via the transparent measurement cell 2 and the scattered light receiving unit window 1 c. A detection signal proportional to the amount of received light is output. Although not shown, the cable connected to the scattered light receiving unit 7 is drawn out through the lid.

  The transmitted light receiving unit 8 receives the transmitted light transmitted between the floating particles and the like among the light beams emitted from the light emitting unit 6 through the transparent measurement cell 2 and the transmitted light receiving unit window 1d. Outputs a proportional detection signal. The lead wire 8 a connected to the transmitted light receiving part 8 is drawn out through the lid part 9.

  The lid portion 9 is provided to seal the accommodation hole 1a from the outside, and prevents water from flowing in even in water such as rivers, lakes, and aeration tanks. Further, the lead wires 6a and 8a can be pulled out without water entering.

  In the SS densitometer having the above configuration, the main body 1 is immersed in a river, a lake, an aeration tank or the like, and measurement is performed at a predetermined cycle. That is, when the piston 4 is driven and raised by the lifting device, the liquid sample to be measured is introduced from the water and flows into the detection unit 2a. In this state, a control circuit (not shown) causes the light emitting unit 6 to emit light, and calculates a ratio between the scattered light amount and the transmitted light amount based on detection signals from the scattered light receiving unit 7 and the transmitted light receiving unit 8 at this time. The SS concentration corresponding to the ratio is calculated.

  The main part of the SS densitometer as shown in FIG. 4 is described in, for example, Non-Patent Document 1 below.

Electrochemical Instruments Co., Ltd., TECHNICAL INFORMATION, NO.27-14, “SS Densitometer”, p.3, Fig. 3, July 1995

In this type of densitometer, sample introduction / discharge operation by vertical movement of the piston, light emission operation of the light emitting unit, SS concentration calculation processing using the detection signal of the light receiving unit, etc. are repeatedly executed at a predetermined cycle by a series of measurement sequences. is doing. For this reason, if an abnormality occurs that causes the piston 4 to stop for some reason, a series of measurement operations including the introduction and discharge of the sample becomes impossible. Therefore, a proximity sensor, a position sensor, etc. are arranged in the vicinity of the piston 4. Thus, an abnormal operation of the piston 4 is detected in advance.
However, in the case of using the dedicated sensor described above, the parts cost and wiring cost increase, and the arrangement space of the sensor and the lead wire for wiring must be taken into consideration. There has been a problem that maintenance work such as replacement becomes complicated.

  Accordingly, the present invention can reliably detect abnormal operation of a sample introduction member such as a piston without using a dedicated sensor, reducing the number of parts and cost, reducing the size and weight of the apparatus, and facilitating maintenance and inspection work. It is intended to provide an analyzer with a self-diagnosis function that can be realized.

In order to solve the above problem, the analyzer with a self-diagnosis function described in claim 1 includes a detection unit into which a sample to be analyzed is introduced,
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
When the level change amount of the detection signal within the piston drive cycle is equal to or less than a predetermined range, an abnormality determination unit is provided that determines that the operation of the piston is abnormal .

The analyzer with a self-diagnosis function described in claim 2 includes a detection unit into which a sample to be analyzed is introduced,
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
Piston when the detection signal when in the top dead center is not the maximum value is, Ru der which operation of the piston with an abnormality determination unit that determines as abnormal.

The analyzer with a self-diagnosis function described in claim 3 includes a detection unit into which a sample to be analyzed is introduced,
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
When the detection signal does not become the minimum value when the piston is at the bottom dead center, an abnormality determination unit that determines that the operation of the piston is abnormal is provided .
Further, the analyzer with a self-diagnosis function described in claim 4 includes a detection unit into which a sample to be analyzed is introduced,
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center,
The detection signal when the piston is at the top dead center is compared with the detection signal when the piston is at the bottom dead center, and the detection signal when the piston is at the top dead center is When the detection signal is smaller than a certain detection signal, an abnormality determination unit that determines that the operation of the piston is abnormal is provided.

  According to the present invention, without using a proximity sensor, a position sensor, or the like, a light-emitting unit and a light-receiving unit provided in advance in the analyzer are used, and the sample introduction member is changed based on the level change of the detection signal by the light-receiving unit. Abnormal operation can be detected. For this reason, the number of parts and the cost can be reduced compared to the case where a dedicated sensor is used, and it is possible to reduce the size and weight of the device without securing the mounting space and wiring space of the sensor. Maintenance inspection work can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of the self-diagnosis apparatus according to this embodiment. As shown in FIG. 1, the self-diagnosis apparatus includes a central processing unit 10, which includes the light emitting unit 6, the scattered light receiving unit 7 and the transmitted light in the SS densitometer shown in FIGS. It is connected to the light receiving unit 8. Then, a control drive signal is output from the central processing unit 10 to the light emitting unit 6, and detection signals (light reception signals) from the respective light receiving units 7 and 8 are input to the central processing unit 10, and an SS concentration calculation process is executed.
Although not shown, the central processing unit 10 includes a control circuit for driving the piston 4 at a predetermined cycle.

Here, the principle of self-diagnosis of the operation abnormality of the piston 4 in this embodiment will be described.
As described above, in this type of densitometer, the piston 4 that reciprocates to introduce / discharge the sample periodically opens / closes the optical path of the light emitting unit 6 and the light receiving units 7 and 8. . When the piston 4 is lifted and is at the position indicated by the solid line in FIG. 4, the light path is opened, and the amount of light received according to the SS concentration of the sample is detected by the light receiving portions 7 and 8, and the piston 4 is shown in FIG. When the light path is lowered to the position indicated by the dotted line and the light path is interrupted, the amount of light received by the light receiving portions 7 and 8 is zero or nearly zero. That is, a periodic level change synchronized with the vertical movement of the piston 4 at the normal time appears in the detection signals from the light receiving units 7 and 8.

However, when the operation of the piston 4 is stopped for some reason, such as a failure of the lifting device that drives the piston 4 or its control circuit, the periodic level change of the detection signal should not appear. For example, when the piston 4 rises and stops at a position where the light receiving optical path of the light receiving unit is opened, an unspecified detection signal corresponding to the SS concentration of the sample is continuously obtained, and the piston 4 is lowered. When stopping at a position where the light receiving optical path of the light receiving unit is blocked, a detection signal that is zero or nearly zero is continuously output, and in any case, a periodic level change does not appear in the detection signal.
Therefore, in the present embodiment, it is determined that the operation of the piston 4 is abnormal when the above-described periodic level change does not appear in the detection signal of the light receiving unit.

The abnormality determination operation described above is executed by the central processing unit 10 in FIG. 1, and its functional block diagram is shown in FIG.
In FIG. 2, reference numeral 11 denotes an abnormality determination unit to which detection signals S7 and S8 from the scattered light receiving unit 7 and the transmitted light receiving unit 8 and a normal piston drive cycle T are input. Reference numeral 12 denotes an alarm output unit that receives an abnormality determination signal from the abnormality determination unit 11 and generates an appropriate alarm. As this alarm, an alarm by voice or visual display, a transmission output, or the like can be considered.

The abnormality determination unit 11 determines whether or not the piston 4 is operating abnormally by detecting the presence or absence of a level change in the detection signals S7 and S8 synchronized with the driving cycle T of the piston 4. Here, in the illustrated example, both the detection signals S7 and S8 from the scattered light receiving unit 7 and the transmitted light receiving unit 8 are input to the abnormality determination unit 11, but at least one of the detection signals (for example, S7) is used. Use it. In the following description, it is assumed that the presence or absence of a level change of the detection signal S7 is detected.
Further, the drive cycle T of the piston 4 input to the abnormality determination unit 11 is a value set in advance by a control circuit in the central processing unit 10 that controls the lifting device of the piston 4.

FIG. 3 shows the relationship between the operation of the piston 4 and the level of the detection signal S7 by the scattered light receiving unit 7, where P is the position of the piston 4 and I is the detection signal S7.
In the same figure, when the operation of the piston 4 is normal, the drive cycle T is increased from the time when the piston 4 is at the bottom dead center (state before sample introduction) to the top dead center (state after sample introduction). This is a series of periods T1, T2, T3, and T4 until the piston 4 is further lowered to reach the bottom dead center and thereafter the piston 4 starts to rise again.
Further, the level of the detection signal S7 changes as shown in the figure corresponding to these periods T1, T2, T3, and T4. Needless to say, the maximum value of the detection signal S7 varies depending on the SS concentration of the sample.

Now, it is assumed that an abnormality occurs in the operation of the piston 4 for some reason. For example, when the piston 4 stops at a position near the top dead center (a position where the light receiving optical path of the light receiving unit 7 is opened) P1, The detection signal of the light receiving unit 7 is, for example, as indicated by I1 in FIG. 3, and is an unspecified value (maximum and constant value in the illustrated example) corresponding to the SS concentration.
If the piston 4 stops at the bottom dead center position P2 (a position where the light receiving optical path of the light receiving unit 7 is blocked), the detection signal of the light receiving unit 7 at this time is as shown by I2 in FIG. A value close to zero is continuously output.

  In any case, when the piston 4 is stopped at a position other than the above (top dead center or other intermediate position), in any case, when the piston 4 is stopped, the detection signal of the light receiving unit 7 is cyclic. Level changes will not appear.

Therefore, the abnormality determination unit 11 in FIG. 2 can detect an abnormal operation of the piston 4 when the level change amount of the detection signal of the light receiving unit is within a predetermined range at least within the original drive cycle T of the piston 4. it can.
Here, even if the operation of the piston 4 is normal, when the SS concentration of the sample is extremely low, the detection signal of the scattered light becomes an extremely small value regardless of the position of the piston 4, but even in this case, the transmitted light A difference depending on the position of the piston 4 should appear in the detection signal. Also, by reducing the value in the predetermined range (for example, zero), even when a low-concentration sample is to be measured, the piston 4 It is possible to determine abnormal operation.

Further, as apparent from FIG. 3, since the detection signal of the light receiving portion should take a minimum value and a maximum value at least in a half period (T1 + T2 or T3 + T4 period) of the driving period T of the piston 4, detection during this period It is also possible to perform abnormality determination by detecting the amount of change in the signal with a differential circuit or the like.
Furthermore, since the level of the detection signal during the period T2 when the piston 4 is at the top dead center should be larger than the level of the detection signal during the period T4 when the piston 4 is at the bottom dead center, An abnormality determination may be performed by detecting the case where they are equal.

  In the above-described embodiment, the SS densitometer whose measurement target is a liquid sample has been described. However, the present invention can be applied to various types of analyzers regardless of a liquid sample or a gas sample.

It is a block block diagram of the analyzer with a self-diagnosis function which concerns on embodiment of this invention. It is a functional block diagram of a part of central processing unit in FIG. It is a timing chart which shows abnormality judging operation by an embodiment of the present invention. It is a block diagram of the principal part of SS densitometer as a prior art. It is AA sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Main-body part 1a: Accommodating hole 1b: Light emission part window 1c: Scattered light receiving part window 1d: Transmitted light light receiving part window 2: Transparent measurement cell 2a: Detection part 3: Tube part 4: Piston 5: Piston wiper Part 6: Light emitting part 6a: Lead wire 7: Scattered light receiving part 8: Transmitted light receiving part 8a: Lead wire 9: Lid part 10: Central processing part 11: Abnormality judgment part 12: Alarm output part

Claims (4)

A detection unit into which a sample to be analyzed is introduced ;
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
An analyzer with a self-diagnosis function, comprising: an abnormality determining unit that determines that the operation of the piston is abnormal when a level change amount of the detection signal within a piston driving cycle is not more than a predetermined range. . A detection unit into which a sample to be analyzed is introduced;
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
An analyzer with a self-diagnosis function, comprising: an abnormality determination unit that determines that the operation of the piston is abnormal when the detection signal does not reach a maximum value when the piston is at top dead center . A detection unit into which a sample to be analyzed is introduced;
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center ,
An analyzer with a self-diagnosis function, comprising: an abnormality determining unit that determines that the operation of the piston is abnormal when the detection signal does not become a minimum value when the piston is at bottom dead center . A detection unit into which a sample to be analyzed is introduced;
A piston that causes the sample to be introduced into the measurement cell and to be discharged from the measurement cell by moving up and down at a predetermined drive cycle set in advance in the detection unit;
A light emitting unit for irradiating the sample introduced to the detection unit with light;
A light receiving unit that receives light from the light emitting unit through the sample;
Processing means for analyzing the sample by a detection signal corresponding to the amount of light received by the light receiving unit,
In the analyzer configured to open the light receiving optical path of the light receiving unit when the piston is at the top dead center, and to block the light receiving optical path of the light receiving unit when the piston is at the bottom dead center,
The detection signal when the piston is at the top dead center is compared with the detection signal when the piston is at the bottom dead center, and the detection signal when the piston is at the top dead center is An analyzer with a self-diagnosis function, comprising an abnormality determination unit that determines that the operation of the piston is abnormal when the detection signal is smaller than a certain detection signal.

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