JPS62108135A - Chemical emission type analyzer - Google Patents

Abstract

PURPOSE:To discriminate the leakage from a piping and the deterioration of a vacuum pump by detecting the vacuum degree in a chamber at all times and judging the abnormality of the vacuum degree. CONSTITUTION:The vacuum degree in the chamber is detected at all times by a vacuum gage 16. The upper limit Vu and lower limit Vl of the vacuum degree in the chamber during the normal operation as well as the reference vacuum degree Vy when the supply of a measuring gas and ozone is stopped are then set in a vacuum degree setting part 22b. The vacuum degree in the chamber is compared with the set value of the vacuum degree setting part 22b in a relational judging part 22a. The clogging in the piping is detected when the vacuum degree during the operation increased to the upper limit Vu or above. A signal to close stop valves 18, 20 for checking when the vacuum degree during the operation decreases to the lower limit Vl or below. The leakage from the piping is announced upon increasing of the ultimate vacuum degree in the stage when the valves 18, 20 are closed to the reference vacuum degree Vy or above. The deterioration of the vacuum pump is announced when the ultimate vacuum degree is lower than the reference vacuum degree Vy. The abnormality relating to the pressure in the chamber is thus correctly detected and the quick dealing with such abnormality is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to a chamber under reduced pressure using a vacuum pump.
N using chemiluminescence from nitrogen oxide No and ozone O3
This invention relates to a chemiluminescent analyzer such as a chemiluminescent No. meter (Chemiluminium No. meter) that measures O concentration.

(Prior Art) In a reduced pressure type chemiluminescent No. meter, chemiluminescence is measured by supplying a measurement gas and ozone through piping to a chamber whose pressure is reduced by a vacuum pump.

A reduced pressure type chemiluminescent No. meter is characterized by much higher sensitivity than a normal pressure type.

(Problems to be Solved by the Invention) The reduced pressure type chemiluminescence analyzer has the following drawbacks due to the use of a vacuum pump.

(1) Ozone flowing into the chamber together with the measurement gas has a strong oxidizing power, which accelerates the deterioration of the oil in the vacuum pump, lowers the degree of vacuum, and eventually lowers sensitivity.

(2) Since a thin capillary or a needle valve with a very small orifice is used to flow the measurement gas and ozone into the chamber, the capillary is likely to become clogged with dust, resulting in a decrease in flow rate and therefore sensitivity.

(3) Even a slight leak in the piping system will cause a large error in the instructions.

Additionally, there are conventional chemiluminescent analyzers that measure and indicate the degree of vacuum in a chamber, but since the pressure is indicated, experience is required to judge whether the analytical value is correct. In addition, the user needs to check the pressure indication from time to time, and if he or she neglects to do so, he or she will not notice the measurement error, and will only know that there is some abnormality in the device when the No concentration value becomes an abnormal value.

SUMMARY OF THE INVENTION An object of the present invention is to provide a chemiluminescence analyzer that allows the user to use the analyzer without being aware of the pressure state within the chamber, and which can notify the user of the type of abnormality if an abnormality occurs. That is.

(Means for Solving the Problems) As shown in FIG. 1, the chemiluminescent analyzer of the present invention has a check stop valve 18. 20, the degree of vacuum in the chamber is constantly detected by a vacuum gauge 16, and the upper limit Vu and lower limit VQ of the degree of vacuum in the chamber during normal operation, and the standard when the supply of measurement gas and ozone is stopped. Vacuum degree setting section 2 that sets the ultimate vacuum degree vy
2b, the degree of vacuum in the chamber is compared with the set value of the vacuum degree setting part 22b, and when the degree of vacuum during operation exceeds the upper limit Vu, a piping clogging is notified, and the degree of vacuum during operation falls below the lower limit ■Ω. It outputs a signal to close the check stop valves 18 and 20 when the check stop valve 1
Comparison in which a piping leak is notified when the ultimate vacuum level when 8, 2.0 is closed is higher than the standard vacuum level Vy, and a notification of vacuum pump deterioration is notified when the ultimate vacuum level is lower than the standard vacuum level Vy. The judgment unit 22a is provided.

(Example) FIG. 2 represents one embodiment of the invention.

Reference numeral 2 denotes a chamber, and the chamber 2 is provided with a sample line piping 4 for supplying a measurement gas and an ozone line piping 6 for supplying ozone. 10 are provided. The flow rate control needle valves 8 and 10 open slightly to send the i+lI constant gas and ozone to the chamber 2. A vacuum pump 12 is provided at the exhaust port of the chamber 2, and the chamber 2 is constantly supplied with measurement gas and ozone, and is evacuated by the vacuum pump 12 to maintain a certain degree of vacuum inside the chamber 2. There is. The light emitted from the chamber 2 is photometered by the detection unit 14, converted to a degree, and a concentration output signal is sent to the outside.

Additionally, a vacuum gauge 16 checks the pressure within the chamber 2. The above configuration is also commonly provided in conventional reduced pressure type chemiluminescent No. meter.

In this embodiment, stop valves 18 and 20 for leakage checking are further provided in the pipes 4 and 6 between the needle valves 8 and 10 for flow rate control and the chamber 2, and these stop valves 18 and 20 are microscopic. A computer 22 controls opening and closing operations.

The microcomputer 22 implements the comparison/judgment section 22a and vacuum degree setting section 22b in FIG. The microcomputer 22 inputs the signal from the vacuum gauge 16, compares it with the set vacuum degrees Vu and VQ, and determines whether the pressure inside the chamber 2 is normal or abnormal.The microcomputer 22 also operates the stop valves 18 and 20 to check for abnormalities. In addition to outputting a close signal,
An abnormal location is determined by comparing the set vacuum degree vy and the output of the vacuum gauge 16. The details of the abnormality are sent to and displayed on the display unit 24 to inform the user.

Next, the operation of this embodiment will be explained according to the flowchart shown in FIG.

The microcomputer 22 constantly checks the degree of vacuum (step SL). Now, when the stop valve 18.20 is open and gas is being measured, if the degree of vacuum rises above the set upper limit Vu (if the pressure decreases), it is impossible for the pump capacity to increase, so the sample line or ozone line or both piping 4
, 6 should be considered to mean that the gas becomes difficult to flow and the degree of vacuum increases. Therefore, a message indicating that the pipe is clogged is displayed (steps S2→S3).

Also, while measuring the measurement gas, the degree of vacuum is Vx (V
x≦vQ) (if the pressure rises), the capacity of the vacuum pump 12 has decreased due to oil deterioration (Cause a), or the flow rate control needle valve 8. This is considered to be because ambient gas (atmosphere) leaked into the pipes 4 and 6 after the IO, and the total flow rate to the chamber 2 increased (cause b). FIG. 3 shows the relationship between the flow rate of gas supplied to the chamber 2 and the degree of vacuum. 30 is a case where the capacity of the vacuum pump 12 is low, and 32 is a case when the vacuum pump 12 is normal. Voa
, Vob is the degree of vacuum reached by each vacuum pump when the supply gas flow rate is set to O. If it is due to a decrease in the capacity of the vacuum pump 12, the degree of vacuum decreases as shown by an arrow 34, and if it is due to pipe leakage, the degree of vacuum decreases along a curve 32 as shown by an arrow 36. Therefore, if the stop valves 18 and 20, which are located close to the chamber 2, are closed, there is no need to consider leakage from the pipes 4 and 6 (if the flow rate approaches 0).
The degree of vacuum within the chamber 2 increases and reaches a degree of vacuum Voa or Vob, which varies depending on cause a or cause a. If the ultimate vacuum degree at this time is Vob, the vacuum pump 12 is normal, and it is considered that there is a leak in the piping system.

Further, if the ultimate vacuum degree is Voa, the capacity of the vacuum pump 12 has decreased, and it is considered that the cause is oil deterioration or the like.

Therefore, when the degree of vacuum during measurement falls below the set value VQ, the stop valves 18 and 20 are closed in response to a signal from the microcomputer 22 (steps S4→S5), and the ultimate degree of vacuum vc is input. The microcomputer 22 compares the ultimate vacuum degree vc with the standard ultimate vacuum degree Vy set between Voa and Vob, and determines that the ultimate vacuum degree Ve is Vy.
If it is above, it will be displayed as a pipe leak. Step S6→s7→
58) If -Vc does not reach vy, it is displayed that the vacuum pump has deteriorated (steps S6→S7→S9).

In addition, the stop valves for checking leaks in the pipes 4 and 6 are not limited to the case where one valve is provided for each pipe 4 and 6 as in the embodiment, but they may be provided at multiple key points for the pipes 4 and 6 to prevent leakage in the pipes. It is also possible to narrow down the leakage location in certain cases.

(Effects of the Invention) In the chemiluminescence analyzer of the present invention, the degree of vacuum in the chamber is constantly detected, and abnormalities in the degree of vacuum are determined based on the degree of vacuum.
In addition, the stop valve on the piping was closed so that leaks in the piping and deterioration of the vacuum pump could be determined. Therefore, even an unskilled person using a chemiluminescent analyzer can correctly grasp abnormal conditions related to the chamber internal pressure. Additionally, since the cause of the pressure abnormality can be identified, it is possible to respond quickly and correctly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the present invention, FIG. 2 is a schematic diagram showing one embodiment, FIG. 3 is a diagram explaining the operation of one embodiment, and FIG. 4 is a flowchart showing the operation of one embodiment. be. 2...Chamber, 4.6...Piping, 12...Vacuum pump, 16...Vacuum gauge, 18.20...Stop Valve, 22...Microcomputer, 22a...
. . . Comparative judgment section, 22b . . . Vacuum degree setting section.

Claims (1)

[Claims] (1) In a reduced-pressure type chemiluminescence analyzer that measures chemiluminescence by supplying a measurement gas through piping to a chamber whose pressure has been reduced by a vacuum pump, a check stop valve is provided in the piping, and a check stop valve is provided in the piping, A degree of vacuum that constantly detects the degree of vacuum with a vacuum gauge, and sets an upper limit Vu and a lower limit Vl of the degree of vacuum in the chamber during normal operation, and a standard attainable degree of vacuum Vy when the supply of gas to the chamber is stopped. A setting section compares the degree of vacuum in the chamber with a setting value of the vacuum degree setting section, and notifies a pipe clogging when the degree of vacuum during operation exceeds the upper limit Vu, and when the degree of vacuum during operation is equal to or lower than the lower limit Vl. output a signal to close the check stop valve when the check stop valve is closed, and notify a pipe leak when the ultimate vacuum level when the check stop valve is closed becomes higher than the reference vacuum level Vy, A chemiluminescent analyzer comprising: a comparison judgment section that notifies vacuum pump deterioration when the ultimate vacuum degree is lower than the reference vacuum degree Vy.