JPS6021443A - Automatic measurement of concentration of hydrofluoric acid of surface treatment liquid for food can made of aluminum - Google Patents

Abstract

PURPOSE:To enable speedy and accurate detection of concentration of hydrofluoric acid, by measuring and operating the voltage proportional to densities of two kinds of standard liquid subjected to measurement in ppm of the hydrofluoric acid and the sample. CONSTITUTION:A memory unit M stores densities of hydrofluoric acid CA, CB of two standard liquids in ppm which have the same composition and concentration as a surface treatment liquid of aluminum food-stuff can, but with a different kinds of hydrofluoric acid. A controlling unit C supplies alternatedly and in due order samples of the standard liquid, treatment liquid to a measuring tank. A detecting unit is incorporated in the measuring tank and delivers voltages EA, EB, EX expressing hydrofluoric acid concentration of each liquid of the standard liquid and the sample. An operating unit A operates the hydrofluoric acid concentration CX of the sample from voltages EA, EB, EX obtained by the detecting unit and CA, CB stored in the unit M and a display unit displays the concentration CX in ppm through calculation.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an apparatus for automatically measuring the concentration of hydrofluoric acid in a solution for treating the surface of aluminum food irons containing hydrofluoric acid.

BACKGROUND OF THE INVENTION In order to perform surface treatment on aluminum food containers, an acidic treatment solution containing hydrofluoric acid is used. In this type of surface treatment process, aluminum food iron is treated at high speed and in large quantities, so it is necessary to maintain a constant hydrofluoric acid concentration in the surface treatment solution, which requires measurements to be carried out quickly and frequently. It has started to be done.

However, there is no known automatic measuring device for the hydrofluoric acid concentration in surface treatment solutions of this type, and it relies on manual analysis, which is extremely inefficient and the analysis work process is cumbersome. So I couldn't process it.

In the above-mentioned manual analysis method, hydrofluoric acid a degree gold is measured by an ion electrode method based on Nernst's theoretical formula, which uses both a fluorine ion selective electrode and a reference electrode (hereinafter referred to as an electrode).

Then, under the same composition and concentration as the acidic treatment solution in the treatment process, using two known standard solutions with hydrofluoric acid concentrations, an electrode potential proportional to the hydrofluoric acid concentration generated between the electrodes was measured. (hereinafter referred to as mV value) is measured, and a calibration curve is created using a semi-logarithmic graph sound, with the hydrofluoric acid concentration on a semi-logarithmic scale and the mV value equally divided.

Therefore, when calculating the hydrofluoric acid concentration from the mV value of the sample using the above-mentioned calibration curve, the higher the hydrofluoric acid concentration, the more
The scale of the semi-logarithm for the hydrofluoric acid concentration becomes smaller and coarser, resulting in individual differences in reading and poor accuracy.

That is, there is a problem that the viscosity of controlling the hydrofluoric acid concentration in the treatment process also deteriorates.

Purpose of the Invention The present invention has been made to solve all of the above-mentioned problems, and it is an object of the present invention to provide a measuring device M that can fully automatically measure the concentration of hydrofluoric acid in a surface treated sample containing hydrofluoric acid with surface accuracy. purpose.

Summary of the Invention In this invention, as shown in FIG. 1, the hydrofluoric acid concentration CA of the first standard solution and the second standard, which have the same composition and concentration as the aluminum food iron surface treatment solution but differ only in the hydrofluoric acid concentration, are The hydrofluoric acid concentration CB of the liquid is stored in the memory M of the microcomputer in units of ppm (100 parts), and at the time of measurement, the first standard voltage EA proportional to the degree of hydrofluoric acid a of the liquid and the second The voltage EB, which is proportional to the hydrofluoric acid concentration of the standard solution, and the voltage EX, which is proportional to the hydrofluoric acid concentration of the sample to be analyzed, are micro-
It is read into the computer, and the calculation section A is
CA and CB in the Pm unit are units of the antilogarithm of the molar concentration (hereinafter referred to as 1), which is called the F unit. )CAl, C84, and then the PF small unit hydrofluoric acid concentration CX of the sample to be analyzed.
is calculated, and finally, CX is inversely calculated to CX in PPm units, and CX is displayed as a PPm value.

The suppressor C controls the opening and closing of various valves V so that the first standard solution, the second standard solution, and the sample are automatically and sequentially alternately supplied to one measuring tank. .

Examples of the invention The present invention will be described in detail with reference to FIG.

1 is filtered in a pot containing an acidic processing solution containing a small amount of hydrofluoric acid. The acidic treatment liquid in tank 1 is led through Nuprey pump 2,
Surface treatment iM is performed by spraying onto the aluminum food pan from a number of spray nozzles (not shown). The acidic treatment membrane used here is “Ridrin $12 O” manufactured by Nippon Paint Co., Ltd.
As typified by the degreasing solution A/#120EJ, it is an aqueous solution containing sulfuric acid as a main ingredient and hydrofluoric acid as an accelerator.

Sample C, which is an acidic processing solution containing a small amount of hydrofluoric acid, is hereinafter referred to as the measurement solution. ) is led to a tube 4 branched from the middle of the piping 3 on the discharge side of the sougere pump 2.

Then, it passes through the pulp 5, flows into the bottom of the measurement tank 6, overflows from the top of the measurement tank 6, and is discharged.

7 is a storage tank containing cleaning water (for example, pure water) for cleaning the measurement tank 6. The washing water passes through the pulp 8 and is supplied to the measuring tank 6 under gravity flow.

9 is prepared in a storage tank of the first standard solution A, in which the concentration of the base agent is prepared at a known concentration that is the same as the concentration of the measurement solution, and the concentration of the accelerator is prepared at a known concentration that is lower than the concentration of the measurement solution. . here,
An aqueous solution containing sulfuric acid as the main ingredient and a concentration of 1-ridorine #1204J as the main component of 1% and 5 (pprr+) of hydrofluoric acid as the accelerator was used. The first standard solution AfC passes through the valve IO and is supplied to the measurement tank 6 under gravity flow.

11, the concentration of the base agent is a known concentration that is the same as the concentration of the measurement liquid;
The concentration of the accelerator hydrofluoric acid concentration basin measurement solution was also mixed at a known concentration (-).The second standard solution B was $17.

Here, 1-ridrine@1 whose main ingredient is saccharic acid is used.
A water bath containing 20 AJOL (total 1%) and 20 (ppm) of 1 JA of hydrofluoric acid as an accelerator was used. Second
4 passes through the pulp 12 and is supplied to the measurement tank 6 in the same flow.

Reference numeral 13 denotes a pulp for discharging the measurement liquid, l or washing water, or first standard solution A in the measurement tank 6.

14. The washing tank 6 was washed by completely stirring 0e + 'l + water, and it was stirred when measuring the concentration of hydrofluoric acid contained in the first standard solution A and the second standard solution B. There is a stirring machine for stirring.

The measurement tank 6 includes a fluorine ion selective electrode 15 for measuring the concentration of free fluorine ions contained in the measurement solution, the first standard solution A, and the second standard solution B, and a comparison electrode. electrode 16
．． Three 'electrodes of the temperature compensation electrode 17 are immersed.

Measurement solution or first standard solution A, second standard solution B
The electrode potential 18 generated between the fluorine ion selective electrode 15 and the reference electrode 16, which is proportional to the free fluoride ion concentration in the fluorine ion a-degree conversion amplifier (hereinafter referred to as PF conversion amplifier) 19 Enter.

Since the electrode potential 18 is a high impedance DC potential difference signal, the PF conversion amplifier 19 includes an impedance conversion circuit 20 that converts the electrode potential 18 into a low impedance signal, and an analog-to-digital converter (hereinafter referred to as an A-D converter). ]2
The signal converting concave path 21 converts the signal level into a signal level for input to 4.

In addition, the PF conversion intensifier 19 has the following features:
By the method disclosed in No. 781, the measurement liquid, the first standard solution A, and the second standard solution are
An automatic temperature compensation circuit 22 is provided which detects the temperature of the standard solution B and automatically corrects changes in the electrode potential 18 due to temperature changes by adjusting the amplification degree of the impedance conversion circuit 20.

The output signal 23 of the PF converter 19 is input to the AD converter 24 .

The A-D converter 24 converts the analog output signal 23 into a binary code digital signal 25, and converts the analog output signal 23 into a binary coded digital signal 25.
25'f: Input to microcomputer 26.

The microcomputer 26 includes a storage device (ROM+RAM) 27 that stores the contents of a control and calculation program and parameters necessary for the program, and a central processing unit that executes control and calculations based on the contents of the control and calculation program. (It is composed of a CPU 928, and a human power device 29 and an output device 30 that send and receive signals to and from external devices.

31 is a keyboard for controlling the microcomputer 26 and setting parameters necessary for the calculation program. The set numerical values of the parameters set on the keyboard 31 are recorded to the microcomputer 26 through the encoder 32f.1. α is done.

A first output signal 33 of the microcomputer 26 is input to a driver 34 .

The driver 34 has pulp 5. 8. It is comprised of a contact relay circuit (not shown) that operates the opening/closing of the 10.12.degree. The opening/closing state of the pulp 5.8.10.degree. 12.13 and the activation of the agitator 14 are determined by the position of the contact of the corresponding contact relay.

The second output signal 35 of the microcomputer 26 is
Input to driver 36.

The driver 36 has a built-in contact relay (not shown) for warning the outside of abnormalities in the electrodes 15 and 16, and the excitation and demagnetization of this contact relay is controlled by the second output signal 35. Then, the driver 36 emits an alarm signal 37 that conveys the position state of the contact of the contact relay to the outside, and using this alarm signal 37, a
When the alarm beeps, an indicator light (not shown) is lit.

The third output signal 38 of the microcomputer 26 is
The entire decoder 39 is inputted to the display 40.

The display 40 is composed of a seven-segment, three-digit light-emitting diode (LED), and digitally displays the hydrofluoric acid concentration of the measurement liquid in hundredth percent units (hereinafter referred to as PPm units).

The fourth output signal 41 of the microcomputer 26,
It is input to a digital-to-analog converter (hereinafter referred to as a DA converter) 42.

Since the fourth output signal is a binary coded digital signal, the D-A converter 42 converts it into an analog signal, and also has a signal level that allows easy connection of devices such as a controller and a recorder, e.g. The 1 to 5 controllers 44 have a setting device 46 configured with a potentiometer circuit, and an amplifier circuit 45 for operating a contact relay 47. The signal corresponding to the hydrofluoric acid concentration managed by the preset setting device 46 and the output signal 43'f corresponding to the hydrofluoric acid concentration of the measurement solution are compared and amplified only when a positive potential deviation occurs. contact relay 4
7 is excited. Then, an output signal 48 that conveys the positional state of the contact of this contact relay 47 to the outside is generated.

Note that this controller 44 may be a controller having adjustment functions of P (proportional action), P■ (proportional integral action), PD (proportional integral action), and PID (proportional integral differential action). .

The output signal 48 of the controller 44 is “Ridorin #120A/
Under the hydrofluoric acid concentration in the degreasing solution of #120EJ, the setting device 46 adjusts the hydrofluoric acid degree to 0.
When a potential difference corresponding to a decrease of 1 to 0.5 (ppm) occurs, the pump 50 is fully operated through the pump operating section 49.

The pump operation unit 49 turns on an electromagnetic switch (not shown) for starting the electric wjer of the pump 50. Opening and closing of this electromagnetic switch is operated by the output signal 48.

The pump 50 replenishes the tank 1 with concentrated hydrofluoric acid, which is an acidic treatment solution used for surface treatment of aluminum food pans.

Next, the control of the microcomputer 26 and the internal code of the calculation program will be explained with reference to FIG.

From the keyboard 31, ■ Hydrofluoric acid concentration CA (PPm
) ■ Hydrofluoric acid concentration CB (pp.
m) ■ Upper limit value EH of the electrode potential 18 of the first standard solution A (mV
) ■ Lower limit value EL of the electrode potential 18 of the first standard solution A (m
V) ■ Difference in electrode potential 18 between the first standard solution A and the second standard solution B, that is, potential gradient hs (rnV) ■ Measuring tank 6 for cleaning water, first standard MA, and second standard solution B supply time, that is, the opening time of pulps 8 and 10.
Opening time T2 [seconds] ■ Washing time with washing water in the measuring tank 6, that is, operation time of the agitator 14 T3 [seconds].

41 [f51 (in manual operation, the state of the contact position of a pushbutton switch (not shown), or in automatic operation, the state of the contact position of a contact relay (not shown) = pulse) to the microcomputer 26 input, step S
If YES is determined in step 2, the following calibration operation is performed. (Step S3) ■ The display 40 holds the displayed numerical value immediately before the calibration signal 51 is input.

■ Close the pulp 5 and completely stop supplying the measurement liquid to the measurement tank 6.

■ The pulp 13 is fully opened for T2 (seconds) to drain the measuring liquid in the measuring tank 6. After T2 (seconds) has elapsed, the pulp 13 is closed.

■ Pulp8. 'tT, C seconds] is opened to supply cleaning water to the measuring tank 6. -rl (seconds), close the valve 8.

■ Operate the stirrer 14 for a total of T3 [seconds] to wash and clean the inside of the measuring tank 6 while stirring the washing water. After T3 [seconds] has elapsed, the agitator 14 is stopped.

■ Open the valve 13 for T2 [seconds] and drain all the cleaning water in the measurement tank 6. After T2 (seconds) has elapsed, the valve 13 is closed.

(2) Open the valve 8 for T1 [seconds] and supply the first standard solution A to the measurement tank 6. After T1 (seconds) has elapsed, valve 8 is closed.

■ Operate the stirrer 14 to completely stir the first standard solution A in the measuring tank 6.

■ Electrode potential of the first standard solution A 18 EA (mV) 7
111I, read all the values and write them down.1. I will.

[Stocks] Stop at agitator 14'.

(Ll) EA (mV)) SEH (mV, 14 or E
Confirm that A C111V, 1:>EL (mV) is obtained.

If EACmv] does not meet the conditions of Section 111,
A second output signal 35 is generated to notify abnormality of the electrodes 15 and 16.

(2) Open the valve 13 (c-T (seconds) to discharge the first standard solution A from the measuring tank 6. After T2 (seconds) has elapsed, close the valve 13.

■ Open the valve 8'kTl (I seconds) to supply cleaning water to the measuring tank 6. After T□ [seconds] has passed, close the noklup 8.

@ The agitator 14 is operated for T3 [seconds] to completely clean the inside of the measuring tank 6 while stirring the cleaning water. After T [seconds] have elapsed, the agitator 14 is stopped.

■ Open the valve 13 for T2C seconds to drain the cleaning water in the Narimirisakiso 6. After T2 (seconds) has elapsed, the valve 13 is closed.

■ 7 < ) Open the v 12 for 11 [seconds] and hold the tears (
15f of the second standard solution is supplied into the soda 6. Tl [seconds] Ma
After that, close No.71/P12.

The O stirrer 14 is operated to stir the second standard solution B in the measurement tank 6.

(2) Measure the electrode potential of 18EB (mV) of the second standard solution B, read and store the value.

■ Stop stirring iso 14.

QD EA (mV) - En (mV) ≧ E 5 (m V
, check that it appears.

If EA (mV, l-EB (mV) does not meet the conditions described in itJ, the second output signal 35 is generated and 'rljJ
Notifies abnormalities of M 15 and 16.

When the calibration operation is completed, the process proceeds to step S4, where the valve 5 is opened and the measurement liquid is supplied to the measurement tank 6.

Then, in step S5, the electrode potential 18Ex (
mV), the values are sequentially read, and the hydrofluoric acid concentration in the measurement liquid is calculated in PPm using the following 7 calculation formulas i, fl, III, and JY.

■ The hydrofluoric acid concentration of the first standard solution in PPm units, that is, the CAC, is stored in the storage device 27 of the microcomputer 26.
PPm) and the unit of the antilogarithm of the molar concentration (hereinafter referred to as
It is called IF unit. ), that is, C;A'(P F
) to be converted by equation 1. (Step S6) ■ Next, read the hydrofluoric acid concentration of the second standard solution in ppm from the storage device 27, that is, cBCppm], and
Convert to the unit CB' (, P'I; ) using the formula. (Step S7) ■ Calculate the concentration of hydrofluoric acid contained in the measurement liquid in PI7 units, that is, Cx'[PF] by the following formula.

(Step S8) ■ From CX'[PF] in ppm unit, that is, CX(p
pm) by the IV formula. (Step 59) 9000 CX-...1v e 'i < P (2,303 A digital signal with a binary code corresponding to the acid concentration is supplied as the third output signal 38 and the fourth output signal 41 to the display 40 and the controller 44, and the a degree of hydrofluoric acid contained in the acidic treatment liquid in the tank 1 is determined. is displayed in PPm, and
Replenishment of concentrated hydrofluoric acid to tank 1'ff: Controlled to keep the hydrofluoric acid concentration constant.

Effects As explained above, this invention automatically calculates and displays the hydrofluoric acid concentration of the sample as a PPm value based on the potential of the electrode immersed in the sample of the surface treatment solution for aluminum food iron. The hydrofluoric acid a degree can be quickly and accurately determined without creating a calibration curve as in the above method, and the hydrofluoric acid a degree of the surface treatment solution can also be quickly managed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an outline of the present invention, FIG. 2 is a block diagram showing a simple embodiment of the present invention, and FIG. 3 is a flow chart showing the operation of the apparatus shown in FIG. 2. 1...Castle, 6...Measuring tank, 15,16.17...
・Electrode, 5, 8.10, 12.13...Valve, 26
...Microcomputer. Patent applicant: Nippon Paint Co., Ltd. Representative Patent Attorney Aoyama Sogai 1 Figure 3 (0) The star is Hokusai 4 Bin A's f degree Ca (typ 笥) Marker Jren β's 91 degree Ca (pp beg) Husk rs (FIVn Grain Fixed Squeezing A1 Medical Potential θ EL Partial Hind Leg ε Pulp LLO, rZ, n Mon T1 (什) 1981 Patent Application No. 12'9939 2 Title of Invention Automatic Acid Concentration Measuring Device 3 Person who makes the correction 4, agent and drawing 7 Contents of the amendment (1) The scope of the claims is corrected as shown in the attached sheet. (2) Line 2 of page 6 of the specification states “Discharge side” 1 discharge side.”
0AJ” [Main ingredient [Ridorine #120AJ
Corrected to 1. (4) On page 7, line 1, ``I mixed it. The second'' was corrected to ``I mixed it, the second.'' (5) On page 10, line 17, “Buzee” is replaced with “Buzze-”
Corrected. (6) Same line 11 @ 9th line ``4th output signal''.
Output signal 41 is corrected to ``. (7) On page 15, lines 10 and 12, "Valve 8" was corrected to "Valve 10." (8) Page 19, line 2 “4th output signal 41 and display 40
"and" was corrected to "as the fourth output signal 41 and the display 40." (9) Figure 1, Figure 3 (, ), Figure 3 (b), Figure 3 (
(Corrected as shown in the attached sheet. Attachment Claims (1) The 7-acid concentration CΔ and the The hydrofluoric acid concentration cB of the standard solution in 2 and 1) l) I
a storage means for storing information in units of fl (hundredth fractions); a first standard solution; a second standard solution; ! 2. A control means for sequentially and alternately supplying samples of the standard solution and aluminum food surface treatment solution to one measurement tank; a first standard solution provided in the one measurement tank and supplied to the measurement tank; A detection means for outputting voltages EΔ, EB:Ey, representing the hydronic acid concentration of the second standard solution and each sample solution, and voltages EA, EB obtained from the detection means.
, EX and C8 and CB stored in the storage means, a calculation means for calculating the hydrofluoric acid concentration CX of the sample, and a display means for displaying the concentration Cχ obtained from the calculation means in l) l) m units. An automatic measuring device for measuring the concentration of 7-acid in an aluminum food iron surface treatment solution. Figure 1

Claims (1)

[Claims] (1) Same composition as aluminum food surface treatment, a)
! The hydrofluoric acid concentration CA of the first standard solution and the hydrofluoric acid concentration CB of the second standard solution, which differ only in the hydrofluoric acid concentration under i, 'r:
a storage means for storing in units of ppm (percentage per hundred);
a control means for sequentially supplying the standard solution, the second standard sample, and the sample of the aluminum surface treatment solution to one measuring tank in an alternating manner; a detection means for outputting voltages EA, l!, B, and EX representing the fluorine concentration of the supplied first standard, second standard solution, and sample; and a voltage EA obtained from the detection means;
EB, EX and CA, C1 whose "L" is recorded in the storage means
An automatic measuring device for the hydrofluoric acid concentration of an aluminum food surface treatment solution, which is characterized in that the hydrofluoric acid concentration of the sample is from 0 to 0.