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Numerous industrial applications require a hard wear-resistant surface called the case, and a relatively soft, tough core. This is achieved by case hardening. Information above various case hardening methods is given in this article. The first three methods change the chemical composition, carburizing by the addition of carbon, nitriding by the addition of nitrogen and cyanidingcarbonitriding by the addition of both carbon and nitrogen. The last two methods do not change the chemical composition of the steel and are essentially shallow-hardening methods. In flame and induction hardening the steel must be capable of being hardened and therefore, the carbon content must be about 0.30 percent or higher.

The information contained in this booklet represents a significant collection of technical information on Fundamentals, Troubleshooting & Maintenance of Ash Handling Plants and Pneumatic Conveying Systems for Bulk Materials. This information will help to achieve increased reliability at a decreased cost. Assemblage of this information will provide a single point of reference that might otherwise be time consuming to obtain. Most of information, given in this booklet is taken from various sources listed in the references list given at the, end of this booklet. For more information, please refer them.

The information contained in this booklet represents a significant collection of technical information on construction, working, operation and maintenance of electrostatic precipitators (ESPs). This information will help to achieve increased reliability at a decreased cost. Assemblage of this information will provide a single point of reference that might otherwise be time consuming to obtain. Most of information given in this booklet is mainly derived from the literature on the subject indicated in the reference list given at the end of this booklet. For more information, please refer them. All information contained in this booklet has been assembled with great care. However, the information is given for guidance purposes only. The ultimate responsibility for its use and any subsequent liability rests with the end user

In pneumatic conveying systems handling fine or dusty material, the method of filtration that has become almost universally adopted is a bag type fabric filter. These filters are commonly called baghouses. Most baghouses use long, cylindrical bags (or tubes) made of woven or felted fabric as a filter medium.During cleaning, dust that has accumulated on the bags is removed from the fabric surface and deposited in the hopper for subsequent disposal. Depending on the typeconstruction of baghouse, cleaning can be carried out while the baghouse is on-line (filtering) or is off-line (in isolation).Standard fabric filters can be used in pressure or vacuum service, but only within the range of about ± 640 millimeters of water column (25 inches of water column). Well-designed and operated baghouses have been shown to be capable of reducing overall particulate emissions to less than 0.05 gm3 (0.020 grft3 ), and in a number of cases, to as low as 0.002 to 0.011 gm3 (0.001 to 0.005 grft3).

As shown in above figure, all pneumatic conveying systems, whether they are of the positive or negative pressure type mainly consist of a feeding system and a separation system. The system requires gas, usually air to convey materials. For hygroscopic materials, dry air can be used and for potentially explosive materials, an inert gas such as nitrogen can be employed. Information on fundamentals for conveying material pneumatically is given in this chapter.

When there is only one gear on each shaft, as shown in above figure, the assembly is known as simple gear train. The gears are represented by their pitch circles.When the distance between two shafts is small, gear 1 and gear 2 are made to mesh with each other to transmit motion from one shaft to the other, as shown at (a) in above figure. Since gear 1 drives gear 2, gear 1 is called the driver and gear 2 is called the driven or follower. It may be noted that the motion of the driven gear is opposite to the motion of driving gear. If