Select a suitable measuring sensor for the following situati

Select a suitable measuring sensor for the following situations and justify why it would be suitable.

(a) An accurate displacement sensor for measuring strain (very small displacements) in tensile test specimens (eg in Tensile testing machine to determine Elastic modulus). (b) A sensor for measuring vibrations on a large item of machinery.

(c) A temperature sensing device that could be used as a switch eg in an over-temperature safety cut-out situation.

(d) A temperature sensor for measuring furnace (~1300°C) temperatures.

(e) A pressure indicator for a steam line.

(f) A simple level indicator for showing tank level in a water supply tank.

(g) A flow meter to measure total amount of water consumed by a household.

(h) A flow meter for measuring mass flow directly (rather than volume flow).

Solution

(a) An extensometer is a device that is used to measure changes in the length of an object. It is useful for stress-strain measurements and tensile tests. Its name comes from \"extension-meter\". It was invented by Charles Huston who described it in an article in the Journal of the Franklin Institute in 1879. Huston later gave the rights to Fairbanks & Ewing, a major manufacturer of testing machines and scales.

(b) A shock data logger or vibration data logger is a measurement instrument that is capable of autonomously recording shocks orvibrations over a defined period of time. Digital data is usually in the form of acceleration and time. The shock and vibration data can be retrieved (or transmitted), viewed and evaluated after it has been recorded.

(c) A thermal cutoff is an electrical safety device that interrupts electric current when heated to a specific temperature. These devices may be for one-time use or may be reset manually or automatically.

(d) A pyrometer is a type of remote-sensing thermometer used to measure the temperature of a surface. Various forms of pyrometers have historically existed. In the modern usage, it is a device that from a distance determines the temperature of a surface from the spectrum of thethermal radiation it emits, a process known as pyrometry and sometimes radiometry.

(e) The most obvious gauge accessory is a shutoff valve between it and the process, which allows blocking while removing or performing maintenance. A second valve is often added for one of two reasons: draining of condensate in vapor service (such as steam), or, for higher accuracy applications, to allow calibration against an external pressure source

(f) Water Level Indicator with Alarm : Basically the unit is made up of various sensors acting as a switch. Let me explain in a simple way. What happens is when you turn on you water pump, the water starts to get pumped from your underground reservoir or from your underground water supply from the pipes to your water tank. In the tank there is a set of sensors ( to be precise there are 7 sensors), in the water tank.

(g) Displacement water meters : This type of water meter is most often used in residential and small commercial applications and homes. Displacement meters are commonly referred to as Positive Displacement, or \"PD\" meters. Two common types are oscillating piston meters and nutating disk meters. Either method relies on the water to physically displace the moving measuring element in direct proportion to the amount of water that passes through the meter. The piston or disk moves a magnet that drives the register.

(h) Flowmeters are devices that measure the amount of liquid, gas or vapor that passes through them. Some flowmeters measure flow as the amount of fluid passing through the flowmeter during a time period (such as 100 liters per minute). Other flowmeters measure the totalized amount of fluid that has passed through the flowmeter (such as 100 liters).Flowmeters consist of a primary device, transducer and transmitter. The transducer senses the fluid that passes through the primary device. The transmitter produces a usable flow signal from the raw transducer signal. These components are often combined, so the actual flowmeter may be one or more physical devices.