What Is Thermal Shock?
Thermal shock is caused by rapid temper change; this may be from hot to cold or cold to hot. Some of the glasses are made up of both thick pieces and thin pieces of glass. For example, the jugs, which are thick at the handle and base and thin throughout the trunk. When the thin pieces change temperature they expand or contract while the thicker pieces remain the same, this causes friction and the piece may crack. Another example of thermal shock is when candles are allowed to burn too closely to the rim of the candleholders causing rapid temperature change.
Thermal shock describes the way in which some materials are prone to damage if they are exposed to a sudden change in temperature. Glass and certain other materials are vulnerable to this process, in part because they do not conduct thermal energy very well. This is readily observed when a hot glass is exposed to ice water—the result is a cracked, broken, or even shattered glass. Thermal shock is a reaction to a rapid and extreme temperature fluctuation, but the process is somewhat more complicated than this. The shock is the result of a thermal gradient, which refers to the fact that temperature change occurs in an uneven fashion. Temperature change causes expansion of the molecular structure of an object, due to weakening of the bonds which hold the molecules in formation. The existence of the thermal gradient means this expansion occurs unevenly, and glass in particular is very vulnerable to this process. In the example of the hot glass, this means that the rapid temperature change
This is a condition that exists when metal, or other materials, are heated up and then cooled quickly. The materials expand from the heating process and contract rapidly when cooled. The drive casing is made of cast aluminum which can develop small stress cracks when subjected to thermal shock on a frequent basis. Also, the many bearings and gears inside the drive develop excess wear from the constant dimensional changes that occur during thermal induced expansion and contraction.
Many products expand and contract due to changes in environmental temperature or liquid temperature. The components in CAT PUMPS are designed to withstand normal temperature changes. However, with sudden and severe temperature changes in liquid temperature [hot to cold], damage to the ceramic plungers may occur. This is called thermal shock and will appear as a spider cracking or even splitting of the ceramic plunger. Plungers should be replaced as soon as any spider cracking is seen.
Most glass artists know that glass that breaks due to rapid, uneven temperature change is said to have suffered thermal shock. Why this happens may not be obvious. When solid glass is heated or cooled unevenly, the part of the glass that is heated will expand (or contract if cooled). The glass that isn’t changing temperature stays the same size. The uneven expansion creates a lot of stress inside the glass. If the stress is strong enough the glass will break. That is thermal shock. There are three key characteristics that determine a material’s potential to thermal shock: • First, is expansion rate. Materials that expand and contract quickly due to temperature change are more likely to thermal shock than materials with low expansion rates. • Second, materials that are brittle (i.e. do not stretch or bend far without breaking) are also more likely to thermal shock than flexible materials. • Third, materials that conduct heat well are less likely to thermal shock because, by transferring
