Search results
Results From The WOW.Com Content Network
This was the cause of the Gettysburg Railroad firebox explosion [22] near Gardners, Pennsylvania, in 1995, where low water allowed the front of the crown sheet to overheat until the regular crown stays pulled through the sheet, releasing a great deal of steam and water under full boiler pressure into the firebox. The crown sheet design included ...
The Reactor Protection System (RPS) is a system, computerized in later BWR models, that is designed to automatically, rapidly, and completely shut down and make safe the Nuclear Steam Supply System (NSSS – the reactor pressure vessel, pumps, and water/steam piping within the containment) if some event occurs that could result in the reactor entering an unsafe operating condition.
The total carryover is the sum of the two. Vaporous carryover generally increases with increasing steam pressure. In low pressure boilers, mechanical carryover prevails, possibly with the exception of more volatile impurities, such as silica. Impurity carryover can cause corrosion and fouling of steam turbines, reheaters, and superheaters.
A steam boiler evaporates liquid water to form steam, or gaseous water, and requires frequent replenishment of boiler feedwater for the continuous production of steam required by most boiler applications. Water is a capable solvent, and will dissolve small amounts of solids from piping and containers including the boiler.
If a steam explosion occurs in a confined tank of water due to rapid heating of the water, the pressure wave and rapidly expanding steam can cause severe water hammer. This was the mechanism that, in Idaho, USA, in 1961, caused the SL-1 nuclear reactor vessel to jump over 9 feet (2.7 m) in the air when it was destroyed by a criticality accident ...
On a steam locomotive, the cutoff is controlled by the reversing gear. The point at which the inlet valve closes and stops the entry of steam into the cylinder from the boiler plays a crucial role in the control of a steam engine. Once the valve has closed, steam trapped in the cylinder expands adiabatically. The steam pressure drops as it expands.
Although the definitions are somewhat flexible, it can be said that older steam generators were commonly termed boilers and worked at low to medium pressure (7–2,000 kPa or 1–290 psi) but, at pressures above this, it is more usual to speak of a steam generator. A boiler or steam generator is used wherever a source of steam is required.
This cut-off allows the steam to then expand within the cylinder. [1] This expanding steam is still sufficient to drive the piston, even though its pressure decreases as it expands. [i] As less steam is supplied in the shorter time for which the valve is open, use of the expansion valve reduces the steam consumed and thus the fuel required. [2]