CHAPTER 1: INTRODUCTION
WATER;
Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients.
MECHANISM FOR PULLING WATER;
1.2 MACHINE DESIGN
and
Engineering Drawing
It may also involve the application of other subjects, such as electrical theory, thermodynamics
and hydraulics as in the design of electric motors and geaeotors, LC Engines and Steam engines
and turbines, gas turbines, water pups, water (urbines and other hydraulic machines, ec,
1.1.1. SOME DESIGN DEFINITIONS
I. Empirical Design: The design based on pust experience and existing practice is known
as the ‘Empirical Design’. In this, various dimensions are set out as a proportion of certain main
dimension, e.g, the various dimensions of a flange coupling are given as proportions of the shaft
diameter. The conditions under which certain machine elements serve are many and varied and, therefore,
are not subject 0 accurate and detailed evaluation. Because of this, machine designers widely use
approximate formulas and empirical relations. The centre distance of belt drives is taken in terms
of diameters of the (wo pulleys, and so on.
2. Rational Design : (tis purely a mathematical design and it is based upon principles of
mechanics, etc. In this design, the different relations developed/studied in the mechanics of solids
are used (0 decide the different dimensions of a product.
3. Combined Rational and Empirical Design : As the heading indicates, it is a combination
of rational and empirical approach for doing a design. In this, the design of a component is based on
solid mechanics, but in no case the individual dimension is to be less than the existing or past practice,
For example, the various dimensions of a knuckle joint are initially taken in proportion to the diameter
of the rods to be joined. These dimensions are then checked for strength with the help of appropriate
relations.
4. Design by Evolution : In the past, the technology development was slow. The society
was not eager or impatient for new engineering designs. The designs tended to evolve over a long
span of time. The designing was thought to be an activity of grey haired persons who will obediently
translate practical needs into drawings of products. Devices or technical systems changed gradually,
each change making a small improvement on the previous model. The designs were without adequate
reasons. The leisurely pace of technological changes reduced the risk of making major errors. This
was design by evolution.
5. Designby Innovation : These days the competition has widened. The slow pace of technological
changes is not the need of the day. Present circumstances require bolder, faster improvements. A new
design is based on ideas and concepts not tried earlier. So the technical risks which the designers
must face today are very great. The need of evaluating information in the face of uncertainty and
to analyze complicated interactions of components is immense. So the products are to be designed
de-novo. This is design by innovation.
6. New Design : These designs are created from a scratch through the application of scientific laws, technical ability and creative thinking. In order to venture successfully into new design fields,
personal qualities of high order are needed in the designer. Locomotive, aeroplanes, steam engines,motor car, etc. are some of the examples of the same. It is of course quite difficult to make a newd design.
New design is also called as ‘Inventive or creative design’. A designer's work may border
on invention. If a problem arises that suggests a machine for the solution and no suitable machine
exists, a designer will have to create it. He is, at this stage, more, interested in how the job is to
be done than what materials he should use and how the parts should be proportioned. Here, we give
1.2 MACHINE DESIGN
and
Engineering Drawing
It may also involve the application of other subjects, such as electrical theory, thermodynamics
and hydraulics as in the design of electric motors and geaeotors, LC Engines and Steam engines
and turbines, gas turbines, water pups, water (urbines and other hydraulic machines, ec,
1.1.1. SOME DESIGN DEFINITIONS
I. Empirical Design: The design based on pust experience and existing practice is known
as the ‘Empirical Design’. In this, various dimensions are set out as a proportion of certain main
dimension, e.g, the various dimensions of a flange coupling are given as proportions of the shaft
diameter. The conditions under which certain machine elements serve are many and varied and, therefore,
are not subject 0 accurate and detailed evaluation. Because of this, machine designers widely use
approximate formulas and empirical relations. The centre distance of belt drives is taken in terms
of diameters of the (wo pulleys, and so on.
2. Rational Design : (tis purely a mathematical design and it is based upon principles of
mechanics, etc. In this design, the different relations developed/studied in the mechanics of solids
are used (0 decide the different dimensions of a product.
3. Combined Rational and Empirical Design : As the heading indicates, it is a combination
of rational and empirical approach for doing a design. In this, the design of a component is based on
solid mechanics, but in no case the individual dimension is to be less than the existing or past practice,
For example, the various dimensions of a knuckle joint are initially taken in proportion to the diameter
of the rods to be joined. These dimensions are then checked for strength with the help of appropriate
relations.
4. Design by Evolution : In the past, the technology development was slow. The society
was not eager or impatient for new engineering designs. The designs tended to evolve over a long
span of time. The designing was thought to be an activity of grey haired persons who will obediently
translate practical needs into drawings of products. Devices or technical systems changed gradually,
each change making a small improvement on the previous model. The designs were without adequate
reasons. The leisurely pace of technological changes reduced the risk of making major errors. This
was design by evolution.
5. Designby Innovation : These days the competition has widened. The slow pace of technological
changes is not the need of the day. Present circumstances require bolder, faster improvements. A new
design is based on ideas and concepts not tried earlier. So the technical risks which the designers
must face today are very great. The need of evaluating information in the face of uncertainty and
to analyze complicated interactions of components is immense. So the products are to be designed
de-novo. This is design by innovation.
6. New Design : These designs are created from a scratch through the application of scientific laws, technical ability and creative thinking. In order to venture successfully into new design fields,
personal qualities of high order are needed in the designer. Locomotive, aeroplanes, steam engines,motor car, etc. are some of the examples of the same. It is of course quite difficult to make a newd design.
New design is also called as ‘Inventive or creative design’. A designer's work may border
on invention. If a problem arises that suggests a machine for the solution and no suitable machine
exists, a designer will have to create it. He is, at this stage, more, interested in how the job is to
be done than what materials he should use and how the parts should be proportioned. Here, we give
FILTER;
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