Thermowells: Overview

Thermowell Overview

Immersion Length ("U" Dimension"- For best teamperature measurement accuracy, the "U" dimension should be long enough to permit the entire temperature sensitive part of the measuring instrument to project into the medium bearing measured. Liquid temperature measurement: A properly designed thermowell will extend into the fluid an amount equal to the length of the temperature sensitive zone plus one inch or greater. Gas temperature measurement: A properly designed thermowell will extend into the fluid an amount equal to the length of...

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Selecting the Right Sensor

Selecting The Right Temperature Sensor

Imagine that you are an Instrumentation Engineer. You are looking at the prints for a new plant, and you see the many locations marked out for temperature transducers. You ask yourself; What has been specified to fill each space? RTD for their high accuracy and linearity? Or thermocouples because of their lower cost and familiarity? Has anything been specified to fill these spaces? The selection of what type of temperature tranducer to be used affects many other aspects of the...

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Temeprature Scales: In-Depth

Temperature Scales In Depth

The Farenheit scale is used by the Unitied States to define temperature. The common temperature points are 32 and 212 F To test a thermometer, distilled water is cruched into 1mm particles, is put into a beaker and filled with distilled water. The perfect scientific method is one which when the top of the ice pack is pushed down inside the beaker, the water braely rises to cover the ice pack. A saturated snow cone effect is what your...

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Selecting Elements

How to Select a Temperature Sensor Element

RTD elements are used to manufacture temperature sensors. A resistance element is the temperature sensing component at the heart of an RTD or resistance thermometer. Typically, they cannot be used in their bare form, but may be built into a probe or assembly which will enable them to withstand various conditions of their application. Each has a pre-specified resistance value at a known temperature which changes in a predictable fashion. In this way, by measuring the resistance of the element, the...

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Selecting Thermowells

How to Select a Suitable Thermowell

How to Select a Suitable Thermowell In many pressurised processes it is often not possible or advisable to insert the temperature instrument directly into the media being measured. A thermowell protects the temperature instrument, permits the instrument to be exchanged or calibrated, and keeps dangerous or expensive media within the process installation. To make a proper selection of a thermowell one must also take into account the thermal lag (response time), the sensing accuracy as well as the service condition, i.e....

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Safe Food Handling

Safe Food Handling Procedures

Safe Food Handling Procedures- Today we'll look at the safe food handling procedures that you need to follow – from the grocery store to the table. These will help you save money, because you will understand why food spoils and when you do or don't need to throw it away. It will also help you make your buying decisions when your supermarket suddenly has a "special" on meat because their refrigeration broke down. Is it worth the risk? You wonder. Understanding...

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RTD Theory

RTD Theories and Standards

Theory of Operation A basic physical property of a metal is that its electrical resisivity changes with temperature. All RTDs are based on this principle. The heart of the RTD is the resistance element. Several varieties of semi-supported wire-wound fully supported bifilar wound glass, and thin film type elements are shown here. Some metals have a very predictable change of resistance for a given change of temperature; these are the metals that are most commonly chosen for fabricating an RTD....

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Roller Bearings: In-Depth

Roller Bearings In Depth

A rolling-element bearing is a bearing which carries a load by placing round elements between the two pieces. The relative motion of the pieces causes the round elements to roll with very little rolling resistance and with little sliding. One of the earliest and best-known rolling-element bearings are sets of logs laid on the ground with a large stone block on top. As the stone is pulled, the logs roll along the ground with little sliding friction. As each log...

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Blind Flanges

In Depth: Blind Flanges

Blind Flange A Blind Flange has no bore, and is used to close ends of piping systems. A blind flange also permits easy access to a line ones it has been sealed. The blind flange is sometimes machined to accept a pipe of the nominal Size to which reduction is being made. The reduction can be either threaded or welded. Stainless Steel : ASTM A 182, A 240 Grade : F304, 304L, 304H, 316, 316L, 316Ti, 310, 310S, 321, 321H, 317, 347,...

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Bearing Temperature

Bearing Temperature

The stabilized operating temperature of a bearing is the result of many factors. The key influences on operational temperature are bearing style, lubrication type, operational factors, environmental conditions and level of maintenance The particular bearing style (ball, roller, sleeve, etc.), the shaft mounting style (slip fit, adapter mounted, press fit, etc.) and auxiliary items (housings, seals, shields, flingers, etc.) all contribute to a final operating temperature. For a given set of application conditions, a particular bearing type will generate...

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