JPH0773520B2 - Crystal can control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to improvement in switching control of a plurality of bread tanks having different solution purities in an automatic crystallizer for producing a sugar or the like.

<Prior Art> An outline of an automatic crystallizer using a crystal can is described with reference to FIG. A solution F to be crystallized in an upright crystal can 1 having a heating part 2 is supplied into the can via a solution supply pipe 3 and a solution valve 4. The heating steam S is supplied to the heating unit 2 in the crystal can via the pipe 5 and the control valve 6.

The solution is heated to evaporate and concentrated, and the solution is replenished. When the crystallizing concentration at which crystals can be precipitated is reached, powder sugar is introduced into the can from the injector 7 via the sugar seed valve 8 when the solution reaches a crystallizing concentration. Put in and generate crystal nuclei suitable for each variety. There is also crystallization in which a crystal-containing slurry is grown as a base without adding powdered sugar.

After that, in order to prevent crystal nuclei from binding to each other and new generation of crystal nuclei (pseudocrystals) of undesired species, depending on the hardness of the slurry in the can, the pipe 9 and the differential valve 10 The water F or the solution F is supplied via the solution supply line 3 and the solution valve 4 through the solution W to continue the concentration and crystal growth.

When the crystal grows to a certain degree, the volume of the crystal in the slurry per unit volume becomes a certain value or more, and the crystals come close to each other, pseudo-crystals are relatively unlikely to occur, and further concentrated than this, When the crystal grows easily and the solution is supplied, the volume in the can increases to a certain value and the crystal grain size grows to the required size, the slurry B discharge valve
It is discharged from the can from 11. The discharged slurry is separated into crystals and a solution by a centrifuge, and the solution is repeatedly used for decoction.

The vapor evaporated from the slurry in the crystal can is vacuum pump 13
Is drawn by the condenser 12 to remove the non-condensable gas and re-condensed by the cooling water. Reference numeral 14 is a pipe for supplying cooling water to the condenser, and 15 is a discharge amount control valve of the pump.

The degree of vacuum in the can, that is, the pressure, is controlled by an air control valve 16 which controls the supply amount of the atmosphere A into the can.

Reference numeral 17 is a pressure sensor inside the can, and PV _P is its measured value, which is led to a pressure controller 18. This controller supplies an operation output MV _P, which is a control calculation of the deviation between the measured value PV _P and the pressure set value SV _P from the hardness program control function 191 in the control device 19, to the control valves 15 and 16, Adjust the internal pressure to SV _P.

20 is a rheometer for measuring the hardness of the slurry in the reactor, PV _R
Is the measured value. 21 is a level sensor that detects the level of the slurry in the can, and PV _H is the measured value.
These measured values PV _R and PV _H are input to the control device 19.

MV _F and MV _W are operation outputs supplied from the control device 19 to the solution valve 4 and the differential water valve 10 via the manual / automatic switching devices 22 and 23, respectively. 24 is a flow rate sensor inserted in the supply line 5 for the steam S, and PV _S is the measured value.

25 is a flow controller, which is an operation output M that controls and calculates the deviation between the measured value PV _S and the flow set value SV _S supplied from the control device 19.
Send VS to the control valve 6 to adjust the steam flow rate to the set value SV _S.

The normal control procedure in such a configuration is to open the solution valve 4 or the differential water valve 10 for a certain time at the timing when the measured value PV _R of the hardness reaches a certain set value to supply the solution or differential water into the can. After loosening the hardness, the solution is concentrated, and when the hardness reaches the set value higher than the previous set value, the same operation is performed, and the crystal is grown while gradually increasing the hardness and the level.

In this case, the physical quantity to be measured of the slurry can be controlled in the same manner not only by the hardness but also by the electric conductivity, the liquid concentration and the like.

The vacuum in the can is constantly controlled by the pressure regulator 18 during the crystal growth period.

26 ₁ , 26 ₂ , ..., 26 _n are a plurality of pan tanks that store solutions F ₁ , F ₂ , ..., F _n having different purities, and 27 ₁ , 27 ₂ , ... 27 _n are the solutions of each pan tank. Solution source valves which are switched and connected to the solution supply line 3, and operation signals mv ₁ , mv ₂ , ..., M given to each solution source valve.
Opened and closed by v _n .

<Problems to be Solved by the Invention> In such a structure, in order to obtain a predetermined volume and purity at the time of crystallization and during roasting, the operator puts a certain amount into a crystal can from pan tanks having different purities. It is determined by experience whether to suck it and the operation signal mv ₁ , mv ₂ ,
..., mv _n is sent to open and close the solution source valve.

Figure 2 shows the amount of solution suctioned from three pan tanks F ₁ , F ₂ and F _3.
FIG. 4 is a characteristic diagram showing the relationship between the switching sequence of Q ₁ , Q ₂ , and Q _{3 and} the integrated value of the total solution flow rate, which is from the start t _{0 of} infusion of sugar to the start of crystal
During the period t ₁ , the solution F ₁ is supplied from the pan tank 27 ₁ , and the accumulated flow rate is Q ₁ (before the start of crystal) at the timing t ₁
It switched to the _second solution F _2.

Furthermore, the suction flow rate is switched to pan tank 27 _third solution F ₃ at a timing t ₂ of the Q _2, the integrated flow rate is Iue at timing t ₃ of Q _3.

In order to obtain a high quality product by performing such a switching operation manually and keeping the grain size of the sugar crystals as the final product constant, it takes skill to judge the timing of the switching, and the product variation occurs. There is an easy problem.

An object of the present invention is to provide a crystal can control device that can solve such problems.

<Means for Solving the Problems> The structural feature of the present invention is that a solution or water is supplied through a solution valve or a differential valve based on a measured value of a specific physical quantity of a slurry in a can and a program set value thereof. In a crystal can control device which is intermittently executed by a plurality of pan tanks for storing the solutions having different purities, and the pan tanks for switching the solutions in the pan tanks and introducing the solutions into the cans are provided. Solution source valve, suction amount calculation means for calculating the suction amount from each pan tank based on the set values of volume, brix, purity and brix of each solution at the time of crystallization and roasting, and each pan tank And a sequence means for switching the pan tanks and supplying the crystallized cans when the integrated value of the amount of the supplied solution from (1) reaches the calculated value of the suction amount of each tank.

<Operation> The crystal can control device intermittently supplies the solution or water through the solution valve or the differential water valve based on the measured value of the specific physical quantity of the slurry in the can and the program set value thereof.

Solutions in a plurality of pan tanks that store solutions of different purities are switched via a solution source valve provided for each pan tank and guided into a can via the solution valve.

The suction amount calculation means calculates the suction amount from each bread tank based on the set values of the volume, the brix, the purity, the brix of each solution, and the purity at the time of crystallization and roasting.

The sequencer switches the pan tanks and supplies the solution to the crystal can when the integrated value of the supplied solution amount from each pan tank reaches the suction amount calculation value of each tank.

<Example> An example of the present invention will be described with reference to FIG. Since the hardware configuration is the same as the elements described in the section of the prior art, description thereof is omitted, and the control device 19 which is a characteristic part of the present invention is omitted.
The explanation about each function of setting, calculation and sequence in the section is added. For simplicity, the pan tank is 27 ₁ , 27
_{The number is 2} , 27 ₃ .

FIG. 3 is a block diagram showing the setting function 192 and the suction flow rate calculation function, the contents of which will be described below.

A setting function 192 sets the following items by man-machine means (not shown).

Volume during crystallization: Q _k (m ³ ) Brix during crystallization: B _k (%) Purity during crystallization: P _k (%) Volume during brewing: Q _t (m ³ ) Brix during brewing: B _t ( %) Iue when purity: P _t (%) solution Brix: B _e (%) solution purity: P ₁ ~P ₃ (%) where the Brix is the weight percent of solids in the solution, and purity Is the weight% of sugar in the solution. The solution brix is common Be (%) in each pan tank, and each pan tank is defined as the solutions F _{1 to} F _{3 having} different purities such as P ₁ , P ₂ , and P ₃ (%).

193 is a suction amount calculation function, and the solution F from each pan tank is
The suction amounts Q ₁ , Q ₂ , Q ₃ (m ³ ) of ₁ , F ₂ , F ₃ are calculated as follows.

Q ₁ = f ₁ (Q _k , B _k , P _k , P ₁ , P ₂ ) Q ₂ = f ₂ (Q _t , B _t , P _t , P ₁ , P ₂ , P ₃ , Be _e , Q ₁ ) Q ₃ = f ₃ (Q _t , Q ₁ , Q ₂ ) The specific gravity value, which is a parameter required for the calculation, has a unique proportional relationship with each Brix value, and is therefore known and determined by a table means.

Specific Gravity at Crystallization: γ _k = f (B _k ) Specific Gravity at Roasting: γ _t = f (B _t ) Solution Specific Gravity: γ _e = f (B _e ) The following items are assumed in the calculation.

1) The Brix value and the specific gravity of each pan tank solution should be the same.

2) Only the solutions F ₁ and F _{2 in the} pan tanks 271 and 272 are taken in until crystallizing.

3) P ₁ > P _k > P _t > P ₃ and P _k > P ₂ Next, the calculation process will be described.

First, assuming that the volume of the solution sucked up to the time of eutectic is V _k , Q _k · γ _k · B _k = V _k · γ _e · B _e ∴V _k = (γ _k · B _k / γ _e · B _e ) Q _k (1) Weight ratio W ₁ / W of solution F ₁ to be mixed by the time of crystallization and the total amount
₂ is W ₁ / W ₂ = (P ₂ −P _k ) / (P ₂ / P ₁ ) (2) From the equations (1) and (2), the solution F drawn from the pan tank 27 _1
1 volume Q _{1 is, Q 1 = (W 1 /} W 2) V k = {(P 2 -P k) / (P 2 -P 1)} × (γ k · B k / γ e · B e ) Q _k (3).

The volume V _t sucked in by the time of roasting is Q _t · γ _t · B _t = V _t · γ _t · B _t ∴V _t = (γt · Bt / γt · Bt) Qt (4) From the total volume balance, Q ₁ + Q ₂ + Q ₃ = V _t (5) From the total sugar balance, (Q ₁ · P ₁ + Q ₂ · P ₂ + Q ₃ · P ₃ ) γ _e = Q _t · P _t · γ _t (6) ( From the equations (3) to (6), Q ₂ = {(γ _t · P _t / γ _e −P ₃ ) V _t + (P ₃ −P ₁ ) Q ₁ }.
Become _{(7) Q 3 = Q t} -Q 1 -Q 2 (8). Therefore, the suction flow rates Q ₁ , Q ₂ , and Q ₃ are calculated by the equation (3),
It can be calculated by the equations (7) and (8).

Sequence function 194, a solution F ₁ of each pan tanks, F _2, a suction amount of F ₃ is Q _1, Q _2, Q operation signal mv ₁ Upon reaching _3, mv _2, mv ₃
Is transmitted to control the opening and closing of the main valves 27 ₁ , 27 ₂ , 27 ₃ to switch and supply each solution to the crystal can.

<Effects of the Invention> As described above, according to the present invention, even if the solution purities of a plurality of bread tanks are not constant, as a result, a sequence control for obtaining a predetermined amount of white shiroki of constant purity can be performed by an experienced veteran. It becomes possible to carry out by automatic operation without an operator.

As a result, it becomes possible to stably produce high quality sugar having a constant particle size.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is an operation explanatory diagram thereof, and FIG. 3 is a block diagram showing a setting function and a suction flow rate calculation function. 1 ... Crystal can, 2 ... Heating part, 3 ... Solution supply line, 4
... Solution valve, 5 ... Steam supply line, 6 ... Steam control valve,
7 ... Seed sugar injector, 9 ... Differential water supply line, 10 ... Differential water valve, 11 ... Discharge valve, 12 ... Condenser, 13 ... Vacuum pump, 14 ... Cooling water supply line, 15,16 pressure control valve, 17 ……
Pressure sensor, 18 ... Pressure regulator, 19 ... Control device, 20
...... Rheometer, 21 …… Level sensor, 24 …… Flow sensor, 25 …… Flow controller, 26 _{1 to} 26 _n …… Pan tank,
27 ₁ ~ 27 _n ...... Solution source valve, 281-28 _n ...... Valve open signal transmitter

Claims (1)

[Claims] 1. A crystal can control device for intermittently supplying a solution or water through a solution valve or a differential valve based on a measured value of a specific physical quantity of a slurry in a can and a program set value thereof. A plurality of pan tanks for storing the above-mentioned solution of purity, a solution source valve provided for each pan tank for switching the solution in these pan tanks and introducing the solution into the can, and at the time of crystallization and roasting Suction amount calculation means for calculating the suction amount from each pan tank based on the set values of volume, brix, purity and brix of each solution, and purity, and the integrated value of the amount of solution supplied from each pan tank is the above suction of each tank. A crystal can control device having sequence means for switching the pan tanks and supplying the crystal cans when the quantity calculation value is reached.