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Showing posts from July, 2012

DIMENSIONS

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What is Dimensioning             A drawing describes the shape and size of a machine part and also furnishes details regarding the material, manufacturing processes, surface finish, and any other instructions required for the final assembly. The shape description of the part is made by drawing its orthographic views with the necessary sections. The size description of the part is made by furnishing details such as the distance between the two surfaces, location of holes, machining operations like drilling and tapping with their sizes, materials, number required, and etc. supply of these details on the drawing for the correct function of the part using lines, figures, symbols, notes, etc, is called dimensioning.          It should be noted that the dimensions shown on a drawing of a machine part should be those that are essential for its production, inspection and correct functioning in the final assembly and should not be misunderstood as those that required to make t

Drafting Technology

 Creation and the Creator : The scientists explore what is, and the engineers create what has never been. A Product Manufactured for the first time may have complicated construction and also may be discarded on the grounds that its production cost is prohibitive. This needs improvement with respect to the cost structure as well as functional simplicity of the structure too. Therefore the creator or the design engineer with his knowledge of the art of production and understanding of the sciences must be constantly engaged in implementing the scientific principles to create new products and also to improve the existing ones. How designs are engineered into reality? To create a new product or to improve the existing one the design engineer must have in His mind a complete picture of its working principles, functional requirements and the production processes involved in its manufacture. His thinking of the product must be conveyed to the workman so as to enable him to

BOILER FEED REGULATOR AND CHECK VALVE

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The boiler feed regulator and check valve shown in  is an improved form of the feed check valve described in art it is assembled from the parts shown in It con sists of two valves, viz, a regulator valve and a check valve, former mounted above the latter. A cast iron elbow  is fitted with a valve seat  to mount the check valve and is bolted to the bottom of the valve body- part no.4 using eight bolts , washers  and nuts a moushroom type of check valve  rests on the check valve seat. The valve has a long stem and is guided well during its lift. The regulating valve seat  is fitted into the valve body . the regulating valve  which is connected to the valve spindle  by means of sleeve nut  the regulating valve has a long cylindrical projection below it to control the upward movement of the check valve. The valve spindle is coupled to the top spindle with help of a coupler a collar 1 and a taper split pin  this joint permits the rotation of the top spindle independent of the valve