WEEK 7

Title of activity

- Research on sensor

Objective

- To find the suitable sensor for Intelligent Fire Fighting System.

Content

- Do some research in internet to find about temperature sensor.
- Study and understand the function of temperature sensor.
- Type K (chromel{90 percent nickel and 10 percent chromium}–alumel)(Alumel consisting of 95% nickel, 2% manganese, 2% aluminium and 1% silicon) is the most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C, chromel positive relative to alumel. It is inexpensive, and a wide variety of probes are available in its −200 °C to +1350 °C / -328 °F to +2462 °F range. Type K was specified at a time when metallurgy was less advanced than it is today, and consequently characteristics may vary considerably between samples. One of the constituent metals, nickel, is magnetic; a characteristic of thermocouples made with magnetic material is that they undergo a deviation in output when the material reaches its Curie point; this occurs for type K thermocouples at around 350 °C .
-  Applications of Type K thermocouples are used for measurements in many different types of environments such as water, mild chemical solutions, gases and dry areas. Engines, oil heaters and boilers are examples of places where they may be found. They are used as thermometers in hospitals and the food industry.
-  The problems may be minimized by using them within the recommended temperatures and environments. Careful calibration, installing them with the proper connectors and wires, and using compensation circuits also serve as aids. K types constructed to reduce the errors include those that are well insulated, pre-aged or are annealed above their operating temperatures. Some users also take care to replace them often. Others switch to type N, which was specifically constructed to be an improvement over K.