DE2814523C2 - Method and device for controlling a centrifuge for separating a two-phase suspension - Google Patents

Description

The invention relates to a method and a device for controlling a centrifuge for separation a two-phase suspension according to the preamble of claims 1 and 3, respectively. Such a method and such a device are known from DE-PS 86 414.

When using the known method, the centrifuge decreases when the sludge chamber is completely filled With the separated sludge, the proportion of the solid phase in the fugat increases, which is why its density increases.

With the device known from DE-PS 11 86 414 the discharge of the centrifuge when a given concentration of the heavy phase is reached controlled in the fugat, d. That is, the valve in the feed line is completely blocked, whereupon unloading takes place.

The invention is based on the object of a method and a device for controlling a centrifuge to indicate the separation of a two-phase suspension, the most effective automatic possible Enable control of the operational sequence.

This task is achieved in the generic method and the generic device by the characterizing features of claims I and 3 solved.

It becomes the change in the flow rate and the content of the solid phase in the starting suspension continuously monitored and the centrifuge only unloaded when the sludge chamber is completely

3 4

field filled and this is maximally compressed. The centrifuge is controlled as follows:

In the centrifuge 1, the starting suspension is ei: v

Furnishings are carried out in the characteristic parts of the pa- and the fugat, the thickened product

Tentanspruchs 2 or claims 4 to 7 are deposited in the sludge chamber of the centrifuge. Using the

give. 5 gauges 3, 2, 6, 5 are each feeding the

The advantageous embodiment of the method includes the starting suspension Q ₀ , the concentration C _{0 of} the

allows gradual contamination of the heavy Zen phase in the initial suspension, which

trifuge due to fixed precipitation to be taken into account- flow rate <? _{F of} the fugat and the concentration Cf of the

and rinse the centrifuge when a specified heavy phase is measured in the fugate. After the

ner minimum value of the performance of the centrifuge is reached io computing device 7 measured parameters

is. Amount of deposited precipitation VV is determined.

The in the characterizing part of claim 7 The value of the concentration Cf of the heavy phase im

described configuration of the device allows Fugat is in the controller 8 with the specified concentration

compared with the aid of the arithmetic unit according to the measured concentration C _p . Depending on this

the concentration of the heavy phase and the flow rate is the same, the feed of the starting suspension is

quantities of the initial suspension and the fugate that controls by the controller 8 on the actuating mechanism

Amount of accumulating precipitation independent of the valve tO for supplying the output

acted on by the physical properties of the working suspension. The amount of low

To determine the product. beat is in the comparison unit 11 with that for I

In the following, the following abbreviations 20 are the product in question more optimal; ..vlenge V _{n of} the Nie- |

used: the stroke compared, when exceeded a ~~

excessive compaction of the precipitation arise

Qo flow of the initial suspension, if it is in the centrifugal force field longer than the time

Qf flow rate of the fugate, T _mix is located As soon as the optimal amount V _{n is} reached,

Qmm specified minimum flow rate, 25 is c'jrch the counter 12 with the counting of the cycle

Qto flow-through of the heavy phase, time t the separation started. The time f is due

Qtf flow of the heavy phase of the fugate, the comparison unit 15 in the comparison unit 13 with

Qt amount of the separated heavy phase, the maximum time T _miI with simultaneous comparison

Co Concentration of the heavy phase in the range of VV and Vs equal to the maximum allowable amount of

gang suspension, 30 rainfall compared. By using the results in

Cf concentration of the heavy phase in the Fugat, summator 14 are added, the time instant becomes the

Cp specified concentration, discharge determined Then the supplied quantity

C _m " specified maximum concentration, ge Q ₀ with the minimum specified Q _min by the

Vr the amount of water in the sludge chamber of the centrifuge comparison unit 16 and the value of the concentration

ee collecting precipitation, 35 Cpder heavy phase in the Fugat with the given

Vs maximum permissible amount of precipitation, maximum value C _msx in the comparison unit Yi

V _n Amount of precipitation when it rises above it. According to the sum of the results of the comparison

Stepping in excessive compression on the summator 14 becomes beyond the need

Suffered when he flushed the centrifuge for more than a certain time after unloading.

T _m tx lingers 40 divorced in the centrifugal force field. The switching of the working cycles of the centrifuge takes place with the help of the control unit 19 by switching

One embodiment of the invention is to switch the valve block 4.

Shown in the drawing and will be explained in more detail below.

purifies it shows de for a centrifuge continuously -cyclic effec-

F i g. 1 a schematic circuit diagram for illustration purposes, compared to the known one, the quality

determination of the control process, characteristic values of the separation process in the centrifuge

Fig.2 control the block diagram of a control device.

for the centrifuge with transmitters for the flow rate. 2 device shown

and the concentration of the solid phase of the output for the automatic control of the centrifuge after the

suspension and the fugat received by a processing unit 50,

are connected, and the device includes encoders 20 and 21 (Fig. 2) for

3 shows the block diagram of the computing device recording the flow rate of the starting suspension and its connections with the sensors as well as the supply and Fugats Q ₀ and Q _F , sensors 22 and 23 for determining the individual parts of the computing unit under the concentration of the heavy Ph? se in the apart. 55 suspension and in the Fugat C ₀ or Cf, t / ei the Ma-

The device contains a centrifuge 1 (Fig. 1), ximum C _{max of} the concentration of the heavy phase in

a concentration meter 2 for measuring the Kon- Fugat, at the minimum Q _{mm of} the flow rate of the

concentration of the solid phase in the starting suspension, starting subject 'Jon, at the maximum Vs of the amount

a flow meter 3 for measuring the flow rate of the precipitate and for the relevant project

the starting suspension, a valve block 4, which addresses the 60 duct optimal amount V _{n of} the precipitate.

Pipes of the centrifuge 1 blocks, a concencing threshold members 24, 25, 26 or 27, corresponding

tration meter 5 for measuring the concentration of the corresponding valves in the pipelines of a centrifuge

heavy phase in the Fugat, a flow meter 6 to 28, a computing unit 29, a pulse generator 30 and

Measurement of the flow rate of the fugate, a computing unit, a pulse counter 31, a decoder 32, zv / ei

direction 7, a controller 8 for the feed, a control 65 OR circuits 33 and 34 for generating

mechanism 9, a control valve 10, comparison units are missing for the unloading and rinsing of the centrifuge

11, 13, 15, 16, 17, a counter 12, summators 14, 18 and a control unit 35 for the valves, a regulator

and a control unit 19 for the valves. 36 for the supply of the starting product and a

Control valve 37 for the supply.

The computing unit 29 is used to calculate the amount of deposited precipitation in the sludge chamber on signals from the sensors 20 and 21 for the flow rates Qc Qf and from the sensors 22 and 23 for the concentration C ₀ , Cr of the heavy phase in the initial suspension and fugate and for Calculation of the parameter according to which the feed of the initial suspension (degree of filling of the sludge chamber) is regulated. ίο

Here, the amount of deposited precipitate is determined by the relationship

V _r -l (C _u -Q "-G - Q _F ) dt

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calculated.

The arithmetic unit 29 is connected to the first input of the OR circuit 33 for generating a command for the discharge via a series circuit comprising the threshold element 27, pulse generator 30, pulse counter 3i and the decoder 32, the second input of which is connected to the arithmetic unit 29 via the threshold element 26 for the maximum amount Vs of the precipitation in the sludge space and whose output are connected to the control unit 35 for the valves.

The output of the transmitter 20 for the flow rate Qo of the output suspension is connected to the input of the threshold element 25 for the minimum flow rate Qmm of the output suspension, the output of which is coupled to the first input of the OR circuit 34 for generating a command for the flushing.

The second input of the OR circuit 34 is connected to the threshold element 24 for the maximum concentration C _{mix of} the heavy phase in the fugat (maximum for entrainment) and its output to the control unit 35

The setup works as follows.

The computing device 29 generates on signals from the encoders 20 and 21 for the flow rate Q _0, Q r of the initial suspension and the Fugats and of donors 22 and 23 for the concentration CC / the heavy phase in the initial suspension and the Fugate a to the quantity Vj of A signal proportional to the precipitate deposited in the sludge chamber of the centrifuge 28, which arrives at the inputs of the threshold elements 26 and 27, as well as a signal arriving at the controller 36 controlling the feed by means of the control valve 37 when the amount of precipitate reaches the value V _n Exceeding an excessive compression of the precipitation can occur if it stays in the centrifugal force field longer than a certain time Tm _1x (the time T _mx and the value V _n depend on the specific type of product), the threshold element 27 responds and switches the pulse generator 30, whose signals arrive at the pulse counter 31. In the decoder 32 there is a number equal to T _m ". The OR circuit 33 is triggered by the decoder 32 or the threshold element 26 for the maximum amount of precipitation in the sludge space, whereby the time of the discharge of the centrifuge is determined.

The signal from the transmitter 23 for the concentration Cr of the heavy phase in the fugate arrives at the threshold element 24 for the maximum entrainment of the heavy phase and the signal from the transmitter 20 for the flow rate Q _{0 of} the output suspension arrives at the threshold element 25 for the minimum flow rate Qnm of the output suspension. The OR circuit 34 responds to one of the threshold elements 24, 25 and sends a signal to the control unit 35 for the valves for rinsing the centrifuge. If a signal arrives at the unit 35 only from the OR circuit 33, a discharge cycle follows, but if a signal also comes from the OR circuit 34, the discharge cycle is followed by a flushing cycle.

The use of the device makes it possible to automatically control the separation process when the operating parameters change, such as feed Q _n , concentration C ₁ , the heavy phase in the starting suspension, flow rate Qr of the fugate, volume VV of the precipitate in the sludge chamber of the centrifuge.

Float flow meters, for example, are used as transmitters 20 and 21 for the flow rate or electromagnetic consumption meters in question.

As a giver for the concentration of the difficult phase vibration and other densitometers can be given a satisfactory level of change within the required range for concentration as well as opacimeter, radioisotope and laser concentration meter to be used.

To ensure an effective continuous quality control for the thickened product by calculation quantitative properties of the separation quality and through objective assessment of the separation process an arithmetic unit is provided, which will be discussed below.

F i g. 3 shows the circuit of the control device for the quality of the separation of liquid two-phase systems, the acts as such a computing unit.

The fluid two-phase separation quality control device includes flow meters 38 and 39 for the initial suspension or the fugate. Concentration meters 40 and 41 for the initial suspension or the Fugat and a unit for determining the key figures of the separation quality. which are made up of first and second multiplier blocks 42 and 43, respectively, an integrator 44 and a summer 45 composed.

The inputs are used to generate a signal proportional to the level of precipitation in the sludge chamber of the multiplier block 42 with the flow meter 38 for the starting suspension and with the concentration meter 40 for their heavy phase and the output via the summator 45 with the integrator 44 connected, the inputs of the second multiplier block 43 to the flow meter 39 and the Concentration meter 41 for the heavy phase of the fugate and the output via the summator 45 with Hern Integrator 44 are connected.

The device works as follows.

An initial suspension is fed into a system 46 via a pipeline 47 for separation

The flow meters 38 and 39 measure the flow rate Qo of the starting suspension and the flow rate Qf of the fugate flowing out of a pipe 48 and the concentration meters 40 and 41 the concentration of the heavy phase (C ₀ and Cf) of the starting suspension and in the fugate.

The signals from the flow meter 38 and the concentration meter 40 are fed to the multiplier block 42, the output of which is equal to the amount (Qto) of the heavy phase of the output system per second

The signals from the flow meter 39 and the concentration meter 41 are fed to the multiplier block 43 supplied, the output signal of which is equal to the amount

(Qtf) Act heavy phase of fugat per second is.

The signals from the multiplier blocks 42 and 43 are given different signs on the summa lor 4 * 5 ntliliiTl. where a signal glcirli ili-r Μι · ιι> τι · (Qi) i \ cr in the heavy phase separated in the appendix 4b is ei / eugl per second. This signal is integrated in the integrator 44 , at the output of which a signal is generated equal to the amount ^ Vr.-of the heavy phase separated from the moment of the beginning of the separation process in the precipitate. ι ο

For this purpose 3 sheets of drawings

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Claims (7)

Patent claims: 1. A method for controlling a centrifuge for separating a two-phase suspension, in which the precipitate is periodically emptied and the concentration (Cf) of the solid phase in the fugate is measured to determine the time of emptying of the precipitate from the centrifuge, characterized in that the Flow rate (Q ₀ ) AtT starting suspension, the flow rate (Qf) of the fugate and the concentration (C ₀ ) of the solid phase in the starting suspension are measured simultaneously and based on these measurements and the measurement of the concentration (Cf) of the solid phase in the Fugat the amount (Vr) of the accumulating precipitation in the sludge chamber is calculated and this amount (Vt) is chosen as the first control parameter that, starting with the achievement of a de? Precipitation permissible minimum amount of precipitation, the duration of the accumulation of the precipitation is measured and this duration is selected as the second control parameter and that the centrifuge either when the specified amount (Vs) of precipitation is reached or - if the specified amount of precipitation is not reached - after expiry the specified duration (T _m , _x ) is emptied. 2. The method according to claim I _1, characterized in that the flow rate (Q ₀ ) of the starting suspension by maintaining the predetermined concentration (C ^ of the remote phase in the Fugat regulated and when the flow rate of the starting suspension is reduced to a '3 minimum allows 3s gene value the centrifuge is rinsed after it has been emptied immediately. 3. Device for performing the method according to claim 1, with a control unit (35) for the Adjusting mechanisms of the centrifuge (28) to which a transmitter (23) for the concentration of the solid phase in the Fugat is connected, characterized by a transmitter (20) for the flow rate of the starting suspension, a transmitter (22) for the concentration of the solid phase in the starting suspension and a Transmitter (21) for the flow rate of the Fugat, and a computing unit (29) for continuous determination the amount of precipitation, at whose entrance all givers (20, 21, 22, 23) and at their Output a channel for controlling the centrifuge (28) according to the amount of precipitate that has accumulated and a channel for controlling the separator according to the duration of the accumulation of the precipitate are connected, and an OR circuit (33) for generating commands for discharge the centrifuge (28), the inputs of which are connected to the outputs of the channels mentioned and its output with the control unit (35) for the actuating mechanisms of the centrifuge (28) accordingly the selected parameters of the control is coupled. 4. Device according to claim 3, characterized in that the channel for control according to the Amount of precipitation contains a threshold member (26). 5. Device according to claims 3 or 4, characterized characterized in that the channel for control according to the duration of the accumulation of the precipitation a threshold element (27), a generator (30) for time pulses, a pulse counter (31) and a decoder (32) which are connected in series. 6. Device according to one of claims 3 to 5, characterized by a device for stabilization the concentration of the solid phase in the fugate by regulating the flow rate of the initial suspension, through one to the output of the transmitter (20) for the flow rate of the starting suspension connected threshold material (24) for the minimum flow rate of the starting suspension, through a with the output of the encoder (23) for the Concentration of the solid phase in the fugat connected threshold member (25) for the concentration of fixed phase in the Fugat and by an OR circuit (34) for generating commands for the immediate Unloading and rinsing of the centrifuge (28), at the inputs of which the outputs of the threshold members (24, 25) are connected and their output with the control unit (35) for the actuating mechanisms the centrifuge (28) is connected 7. Device according to one of claims 3 to 6, characterized in that the computing unit (29) Contains multiplier blocks (42,43), a summator (45) and an integrator (44), which are connected to one another are, the inputs of the first multiplier block (42) with the outputs of the encoder (38, 40) for the flow rate and the concentration of the solid phase in the starting suspension, the inputs of the second multiplier block (43) with the outputs of the sensors (39, 41) for the flow rate and the concentration of the solid phase in the fugate, the input of the summator (45) with the outputs the multiplier blocks (42,43) and the output of the summer (45) with the integrator (44) are connected.