Mechanical Engineering as a Discipline

Mechanical Engineering is a discipline concerned with the application of knowledge in solving real-world problems. Study of calibration techniques is considered as one of the most crucial topics in the field of engineering as it links accuracy as well as quality in instruments thus providing an output with an acceptable amount of error. Calibration is the process of configuring an instrument to provide a result for a sample within an acceptable range. Eliminating or minimizing factors that cause inaccurate measurements is a fundamental aspect of instrumentation design (What is Calibration?).

The results obtained help formulate a relationship between the known values and the values obtained with the use of the measuring technique thus providing a more accurate output. The experiment performed in the lab is based on the calibration of a pressure gauge using a dead weight tester. A deadweight tester is a calibration standard that uses the principle of a pressure balance to calibrate pressure measuring instruments. It uses calibrated weights to apply known pressures to a device under test for a simple and cost-effective solution that covers a wide range of pressure calibrations (Deadweight Testers). A dead weight tester works on the principle of Pascal’s law which states that “In a fluid at rest in a closed container, a pressure change in one part is transmitted without loss to every portion of the fluid and to the walls of the container” (Pascal's principle).

A dead weight tester consists of a pumping piston with a screw that presses it into the reservoir containing a fluid oil, a primary piston that carries the dead weight, W, and the pressure gauge or transducer to be calibrated (How a Dead Weight Tester Works). The primary piston is then loaded with a certain amount of weight W to finalize the desired calibration pressure. It is also noted that the pumping piston pressurizes the whole system by allowing more fluid into the cylinder. In this experiment, the Bourdon Gauge is connected to a dead weight tester. It contains a clear dial through which the mechanism is observed. The Bourdon pressure gauge operates on the principle that, when pressurized, a flattened tube tends to straighten or regain its circular form in cross-section. The Bourdon tube comes in C, helical, and spiral shapes—although most gauges employ the C shape (Flow Control Network). One end of the bourdon tube is held tightly to introduce pressure while the other end, which is linked to a dial and pointer is enabled to move freely.