Nozzle block

Nozzle block Establish steam High tensile carbon... 

We could shut down the turbine and unbolt the steam chest, to expose the nozzle block, which is the wall that separates the steam chest from the turbine case. We could unscrew the existing nozzle, and replace it with a smaller nozzle. A nozzle of 20 percent less diameter would reduce the nozzle cross-sectional area by 36 percent ... 

The majority of bubble-jet printer problems are quality problems. Ninety-nine percent of these can be traced to a faulty ink cartridge. With most bubble-jet printers, the ink cartridge contains the print head and the ink. The major problem with this assembly can be described by If you don t use it, you lose it. The ink will dry out in the small nozzles, blocking them if they are not used at least once a week. 

If a number of cutoff switches are used, they must be installed on separate nozzles and be completely independent. Otherwise, if the nozzle is plugged or the nozzle block valve inadvertently shut, all switches will simultaneously become inoperative. In such cases, they cannot be relied on to lower column relief requirements. The switches must also be regularly tested to be reliable. 

The heart of the process lies in the special nozzle block which is, in effect, a composite shut-off nozzle consisting of two nozzles, one inside the other, and actuated by separate hydraulic cylinders. 

When steam enters a turbine through the nozzle block, its pressure energy is converted to velocity energy. This is an isoentropic expansion, in that the potential of the steam to do work is preserved. When a turbine runs too fast, it may be slowed down in one of two ways. First, allow the governor steam inlet valve to reduce the flow of steam. Not only is the steam flow reduced, but the pressure of the steam flowing into the nozzle block, hence its ability to do work, is diminished. The other way is to reduce the nozzle block cross-sectional area by closing one or more hand valves. This simply reduces the flow of steam but does not impair the ability of the steam to do work. 

If reduced driver steam pressure is to be a long-term condition, a larger nozzle block on the turbine steam inlet may be available at a relatively small price. Sometimes the turbine governor can be adjusted to open wider. Turbine hand valves, used to reduce nozzle block cross-sectional area, should be wide open when trying to maximize horsepower. 

The nozzle block is an internal part o( the turbine. When steam pases through it, the steam s pressure head is converted to velocity head. 

Nozzle blocks Carbon steel ASTM A212 grade A... 

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