FEEDWATER HEATING METHODS Steam-Plant Feedwater-Heating cycle Analysis 5.1 Direct-Contact Feedwater Heater Analysis 5.2 Closed Feedwater Heater Analysis and Selection 5.3 Power-Plant Heater Extraction-Cycle Analysis 5.8 Feedwater Heating with Diesel-Engine Repowering of a Steam Plant

STEAM GENERATION EQUIPMENT AND AUXILIARIES Determining Equipment Loading for Generating Steam Efficiently 4.2 Steam Conditions with Two Boilers Supplying the Same Line 4.6 Generating Saturated Steam by Desuperheating Superheated Steam

Combustion Calculations Using the Million BTU (1.055 MJ) Method 3.1 Savings Produced by Preheating Combustion Air 3.4 Combustion of Coal Fuel in a Furnace 3.5 Percent Excess Air While Burning Coke 3.8 Combustion of Fuel Oil in a Furnace 3.9 Combustion of Natural Gas in a Furnace 3.11 Combustion of Wood Fuel in a Furnace 3.17 Molal Method of Combustion Analysis 3.19 Final Combustion Products Temperature Estimate 3.22

STEAM CONDENSING SYSTEMS AND AUXILIARIES Design of Condenser Circulating-Water Systems for Power Plants 2.1 Designing Cathodic-Protection Systems for Power-Plant Condensers 2.7 Steam-Condenser Performance Analysis

MODERN POWER-PLANT CYCLES AND EQUIPMENT CYCLE ANALYSES 1.4 Choosing Best Options for Boosting Combined-Cycle Plant Output 1.4 Selecting Gas-Turbine Heat-Recovery Boilers 1.10 Gas-Turbine Cycle Efficiency Analysis and Output Determination 1.13 Determining Best-Relative-Value of Industrial Gas Turbines Using a LifeCycle Cost Model 1.18 Tube Bundle

Rolling contact bearings are also called anti-friction bearing due to its low friction characteristics. These bearings are used for radial load, thrust load and combination of thrust and radial load. These bearings are extensively used due to its relatively lower price, being almost maintenance free and for its operational ease.

Brief overview of bearings Bearings are broadly categorized into two types, fluid film and rolling contact type. Fluid Film bearings In fluid film bearing the entire load of the shaft is carried by a thin film of fluid present between the rotating and non-rotating elements. The types of fluid film bearings are as follows, Sliding contact type Journal bearing Thrust bearing Slider bearing Rolling contact bearings In rolling contact bearings,

V - Belt Drives Among flexible machine elements, perhaps V-belt drives have widest industrial application. These belts have trapezoidal cross section and do not have any joints. Therefore, these belts are manufactured only for certain standard lengths. To accommodate these belts the pulleys have V shaped grooves which makes them relatively costlier. Multiple groove pulleys are available to accommodate number of belts, when large power transmission is required.

Flat belts drives can be used for large amount of power transmission and there is no upper limit of distance between the two pulleys. Belt conveyer system is one such example. These drives are efficient at high speeds and they offer quite running. A typical flat belt drive with idler pulley is shown in Fig. 13.2.1. Idler pulleys are used to guide a flat belt in various manners, but do not contribute to power transmission. A view of the flat belt cross section is also shown in the figure.

Flexible Machine Elements Belt drives are called flexible machine elements. Flexible machine elements are used for a large number of industrial applications, some of them are as follows. 1. Used in conveying systems Transportation of coal, mineral ores etc. over a long distance 2. Used for transmission of power. Mainly used for running of various industrial appliances using prime movers like electric motors, I.C. Engine etc.

The operating principle of this type of brake is the following. A flexible band of leather or rope or steel with friction lining is wound round a drum. Frictional torque is generated when tension is applied to the band. It is known (see any text book on engineering mechanics) that the tensions in the two ends of the band are unequal because of friction and bear the following relationship:

Brakes are devices that dissipate kinetic energy of the moving parts of a machine. In mechanical brakes the dissipation is achieved through sliding friction between a stationary object and a rotating part. Depending upon the direction of application of braking force, the mechanical brakes are primarily of three types • • • Shoe or block brakes – braking force applied radially Band brakes – braking force applied tangentially. Disc brake – braking force applied axially.

Variable loading in mechanical joints: Machine parts are often subjected to variable loading. In many cases pulsating or intermittent loads are applied from outside, for example, in punching press forces of very large magnitude is applied for a short while (impulsive force), in crank shafts variable loads act due to nature of force arising from combustion cycle in cylinders

At the end of this lesson, the students should be able to understand: • • • Ways in which eccentric loads appear in a welded joint. General procedure of designing a welded joint for eccentric loading. How to avoid eccentric loading in simple cases.. There are many possible ways in which an eccentric loading can be imposed on a welded joint. A few cases are discussed below. 1.

At the end of this lesson, the students should be able to understand: • • • Meaning of eccentricity in loading. Procedure for designing a screw/bolted joint in eccentric loading. Procedure for designing riveted joint under eccentric loading.

If the load is not very large adhesive joints become very useful in joining metallic or non–metallic dissimilar materials. No special device is needed. But the disadvantage of this joint is that the joint gets weakened by moisture or heat and some adhesive needs meticulous surface preparation. In an adhesive joint, adhesive are applied between two plates known as adherend.

.Design of transverse fillet joint: Consider a single transverse joint as shown in figure 10.4.2. The general stress distribution in the weld metal is very complicated. In design, a simple procedure is used assuming that entire load P acts as

Welded joints and their advantages: Welding is a very commonly used permanent joining process. Thanks to great advancement in welding technology, it has secured a prominent place in manufacturing machine components. A welded joint has following advantages: (i) Compared to other type of joints, the welded joint has higher efficiency. An efficiency 95 % is easily possible. (ii)Since the added material is minimum, the joint has lighter weight.

.Strength of riveted joint: Strength of a riveted joint is evaluated taking all possible failure paths in the joint into account. Since rivets are arranged in a periodic manner, the strength of joint is usually calculated considering one pitch length of the plate.

Rivets as permanent joints: Often small machine components are joined together to form a larger machine part. Design of joints is as important as that of machine components because a weak joint may spoil the utility of a carefully designed machine part. Mechanical joints are broadly classified into two classes viz., nonpermanent joints and permanent joints. Non-permanent joints can be assembled and dissembled without damaging the components.