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Visual interface creation with the software LEA: Application to a fermentor automation.

This page shows the basic principles of the software LEA with an exemple.

Step 1: open an new window

An empty window appears (figure 1)

Figure 1 A new ‘Synoptic’ window

Step 2: Import an image

It can for exemple show the installation to automate (figure 2).

Figure 2 A ‘Synoptic’ window with a bitmap image

Step 3: Add visual components to the window

These visual components are selected in an object toolbox (figure 3).

Figure 3 The visual object toolbox

The component is first selected in the toolbox and appears in the window on the place where the user clicks (figure 4). This object can be moved or deleted as long the configuration mode is activ.

Figure 4 Add a visual component to a window

Step 4: link a channel to this component

To link a channel (actual value, setpoint, etc…) from a device (like a balance, an A/D converted, etc…) to a visual component, the user cliks on the component with the left mouse button. A popup menu appears (figure 5).

Figure 5 Menu popup permettant le choix du canal à visualiser

By clicking on Channel choice, a new window appears. The user can select the channel he wants to link with the component (figure 6).

Figure 6 List of channels wich can be linked to the component

Step 5: Configuration of the linked channel

The linked channel has a default configuration. To check it and to modify it, the user has again to click on the component with the left mouse button. By clicking on Channel configuration in the popup menu, a new window (figure 7) appears. The user can for exemple modify the channel name and calibrate the channel.

Figure 7 Dialog for the configuration of an analog input (here for exemple the Tecon 239 interface box)

Step 6 and following: repeat the same operation for every component to display (step 3 to 5)

The device (here the Tecon 239 interface box) can then be connected and the communication can be started.

An exemple is presented below (Figure 8). It is also very easy to create windows with curves.

Figure 8 An exemple: fermentor automation

These configuration can be modified or completed later. The software offer here a high degree of flexibility, for exemle to add new devices like balances, new probes, etc…

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Cyclone calculation

This example shows how to use the software Cyclone to calculate a cyclone. With a few known parameters, the software will calculate the unkown parameters, like the cyclone dimension and the efficiency for different particles size.

Known parameters air flow rate: 3 m3/s

pressure: 1 bar

gas is air at room temperature: 293 °K

solid density is : 1500 kg /m3

solid distribution is:

particule diameter (micron) inferior cumulated frequency
80.07
120.13
240.3
320.5
480.86
640.94
780.99
961

overall efficiency should be: 0.92

Parameters to calculate

cyclone dimension

efficiency depending on the particule size

pressure drop in the cyclone

Calculation

Step 1
. Enter the gas parameters

Step 2. Enter the solid parameters
Step 3
. Choose an included geometry or entry your own geometry
Step 4
. Choose the known variables combination

Step 5. Choose a model in the list. Here the simualtion has been made with the Lorenz model. Eventually it is possible to enter a particule diameter distribution to calculate the efficiency for every particule size class (not possible with the Barth model).

Then press the simulation button.

The software give you in this case the cyclone dimension, the cut diameter and the pressure drop.

The efficiency for every particules size is available in the parameters window.

Conclusion. With the software Cyclone, you can easily calculate the dimension of a cyclone, without to enter one formula. The software calculations are very quick wich allow you to compare different cyclone parameters in a short time.

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Monitoring the amount of liquid added during a reaction

In many processes it is necessary to know the amount of a component which was added. The Lambda Integrator integrated now in the Preciflow pump, can monitor the amount of liquid added.
1. Presentation of the installation (figure 1)
During a fermentation, maintainance of the pH value is necessary, wich is achieved by addition of acid. A pH controller measures the pH and gives a signal to the pump if addition of acid is necessary. The input of the Lambda integrator is coupled with the pump and the output of the integrator gives an electric signal that is proportional to the amount of liquid that has been added. In summary by use a voltmeter, a recorder or a datalogger, it is possible to visualize on line the amount of acid added.

figure 1

2. Result (figure 2)

Keeping the pH value constant during a whole fermentation. The green line visualises the pH value in the fermenter and the red curves shows the amount of acid added. At the beginning the addition of the acid is slow. With the time the biomass grows wich leads to a increase of the addition of acid. At the end of the biomass growth decrease and so does the amount of acid added.

The Integrator can also be used to monitor enzyme activity ( amidase,…).

figure 2
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Doser system for powder

We present here a set of devices wich connected together permit to add a defined amount of powder in a flask, fully automatically.

Material and methods

A PID controller ist connected to a balance trough a serial RS232 interface (fig. 1 and 2). The doser, wich contains the powder ist controlled by a 0-10 V signal. With 0 V the doser ist stopped, with 10 V it has maximal speed.

figure 1 The devices
figure 2. The connection between the devices
The user enter the amount of powder he want and the duration of the dosing. He press then the start button. The controller calculate at each time the amount of powder which should be added (set point). It compare this value with the weight measured at the scale, and control the speed of the doser.

This configuration has been used to add 3 time 5 g, and 3 time 20 g of NaCl powder. The controller parameter P=2 (proportional) and D = 0 (differential) have been used for this experiment.

Results

The results are reported in the table below. The figure 3 shows set point profile calculated from the controller (red) and the added powder (blue) in fonction time. On this curve you can see how the controller adjust the added amount to the calculated setpoint, wich follows a line.

Set point (g) 5 5 5 20 20 20
Dosing time (min) 2 2 2 3 3 3
Powder amount measured (g) 4.8 5.2 5.3 20.4 20.1 20.0
figure 3. Amount of powder added in function of time

Conclusion

The addition of powder with the doser has a good reproductibility , and a good precision (better then 0.5 g) The same construction can be made for liquid by replacing the doser with a peristaltic pump.

A new controller is in preparation. It will accept set point with 0.1 g precision.