Fabrication of an Optical Cell Dryer for the Spectroscopic Analysis Cells

The main advantage of this technique is that it reduces the drying time which can shorten the time spent on that experiment. This method could be helpful in the field of spectroscopic analysis, such as when performing infrared absorption, or other luminescence measurements. Experiments can be delayed waiting for optical cells to dry.

To reduce drying time design and manufacture a drying device. This device uses three millimeter thick acrylic board to create a case with a partially open top. Machine the board at the front of the case to accommodate the device controls.

Similarly, machine the board at the rear to accommodate four blowers for drying, operated in pairs for the left and right side. Support an acrylic lattice above the case in order to hold optical cells in place. Beneath the lattice, attached to the case is nylon netting to support the cells and allow airflow.

Inside the case are the electronics. Additional acrylic boards shield them from fluids and redirect airflow. A schematic of the electronics reveals the microcontroller at its core.

These connectors on the schematic represent the device controls and indicators. Operation of the completed device is straightforward. Begin by turning the main power switch on.

Here are the power switch and power indicator light represented on the schematic. Next, place optical cells in the mesh of the device, concentrating them on one side if not all spaces are required. When done, select either two blower or four blower operation.

The panel lights will reflect the choice. In the schematic, the fan controls and indicator lights are clustered on a single connector. When operation starts, a pulse with modulation signal from the microcontroller goes to a transistor, which activates the blowers.

The blower output is determined by a preset 10 kilo-ohm variable resistor. Now, set the drying time with an adjustable variable resistor. The selected value is displayed on the OLED.

Once the resistance value is selected, the voltage output is converted by the microcomputer. The microcontroller transfers the converted value, via the inter-integrated circuit protocol to an OLED for display. Press the start button to start the fans and the drying process.

In the schematic, the start button is on the same connector as the power button. Airflow from the fans helps dry the optical cells that are in the dryer. Prepare to measure the natural drying time.

For this, arrange thick absorbent paper on a surface. Get a thoroughly washed, undried, optical cell. Place the optical cell on one part of the paper briefly.

Then move it to a dry part of the paper. Start measuring the drying time when the cell is in the second position. To use the optical cell dryer, also arrange thick absorbent paper on a surface.

Take a washed cell and place it on the paper briefly. From there, place the optical cell in the dryer at the chosen measurement position. Turn on the power, select all four blowers.

Set the time. Then start the dryer. Measure the time in the dryer until the cell is dry.

This diagram represents the different positions in the optical cell dryer. The squares along the bottom row are toward the front of the device. The numbers represent the average of three measured drying times.

The average over all positions is 106 seconds, versus 426 seconds for natural drying. Using the blowers, optical cells can be dried simultaneously and drying time can be considerably reduced. Drying can be same result with a timer, or especially with par-blower.

The measurement of drying time distribution revealed no significant difference in drying time due to the location of the optical cells in the dryer. A critical step is the design of the casing. The challenge is to make the casing compact.

It is also important to prevent ethanol or water from dropping into the device. To reduce drying time the wind volume of the blowers can be increased. But a potential problem is that the optical cells may be brought out of the device.

Other ways to reduce the drying time include increasing the in depth air temperature of blowers, vibrating cells, or both. However, these are future projects, and involve more complicated devices and controlled circuit.

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Journal (Engineering)

Fabrication of an Optical Cell Dryer for the Spectroscopic Analysis Cells

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