The Elpro Hotbox BKT4 datalogger is designed for four-channel continuous recording of temperature with type K thermocouples. The measured values are stored in the internal memory and can be read at any time, printed as graphics or tables.
Wika Instruments South Africa recently carried out a test on the Hotbox datalogger. Measured values can be read directly by a PC through a built-in interface with a simple data cable. The robust aluminium housing permits use of the module in harsh environments.
The measuring interval can be set from 1 second to 2 hours per reading giving a logging period from 2,2 hours to 500 days resulting in 16 000 stored values. The module can physically handle an operational temperature of -10 to 70°C however; can still operate in environments of up to 85°C for 2-3 hours. Battery life is 1-3 years (battery changeable) depending on log interval. The type K thermocouples are connected to the Hotbox by means of standard type K mini plugs. This means that temperature probes, designed to the customer's requirements, can be manufactured by Wika Instruments' temperature factory in Denver, Johannesburg.
The test to be carried out was at a factory specialising in powder coating. The oven continuously feeds the powder-coated products ranging from special fabricated brackets to garden and office furniture. The Hotbox was to be passed though the oven so a profile could be obtained of bottom, middle and top temperatures.
The oven is set to approximately 220°C so the Hotbox had to withstand this temperature. To achieve this, an insulation box was used which can handle temperatures to 300°C. This insulation box is a standard accessory to the Hotbox. The test also had to be carried out without interruptions in the process, as client profit is dependent on high production rates. The oven on test is heated by means of a gas burner and controlled by a SHINKO controller also supplied by Wika Instruments.
The results of this test can be seen in Figure 2. The Hotbox was set up for one reading every second starting immediately. The Hotbox entered the oven at approximately 9:30 in the morning and it can be seen that the test took place over a 15 minute period.
It can be seen that the red trend, which was the lowest point in the oven and was the lowest temperature as can be expected with the green trend being the highest and hottest point in the oven. Between 09:36 and 09:37 the Hotbox passed over the burner situated at the bottom of the oven resulting in the bottom temperature becoming the highest temperature over a one-minute period with temperature inside the oven not exceeding 227°C. With so much information available and printed in table format, further analysis of the entire oven is possible.
What was interesting to Wika Instruments is the pink trend, which was the temperature monitored inside the insulated box with the datalogger. It can be seen that during the entire test this temperature did not exceed 27°C. Wika thanks Brighter Colours Powder Coating for the use of its oven for the duration of this test. All Elpro dataloggers are supplied with a certificate of calibration and have aftermarket support.
For more information contact Paul Giffen, Wika Instruments, 011 621 0000, [email protected], www.wika.co.za
| Tel: | +27 11 621 0000 |
| Email: | [email protected] |
| www: | www.wika.co.za |
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