Pipe, fittings and valves

Impervious graphite centrifugal pumps, pipe fittings, and valves were developed because most chemical processes require the movement of Hquids. Graphite pipe and fittings in sizes ranging from 25 to 635 mm ID are used to convey corrosive fluids. 

Other Types of Piping Joints Packed-gland joints (Fig. 10-135) require no special end preparation of pipe but do reqmre careful control of the diameter of the pipe. Thus the suppher of the pipe shoiild be notified when packed-gland joints are to be used. Cast- and ductile-iron pipe, fittings, and valves are available with the bell cast on one or... 

Push -on joints (Fig. 10-137) require diametral control of the end of the pipe. They are used for brittle materials. Pipe, fittings, and valves are furnished with the bells cast on one or more ends. Considerable force is required to push the spigot through the O ring this is reduced by the extension on the O ring, which causes the friction of the pipe to elongate the cross sec tion of the main portion of the O ring. 

Chemical-Porcelain Pipe Made of dense, nonporous material and fired at 1230°C (2250°F), chemical-porcelain pipe, fittings, and valves are inert to all acids except hydrofluoric but are not usually recommended for alkalies. Surfaces, except when ground for gasketing, are usually glazed for easy cleaning. Working pressures of 0.3 to 0.7 MPa (50 to 100 Ibftin") are recommended for valves and piping. Temperatures of 200°C (400°F) or more can be used, but sudden thermal shocks must be avoided. 

Scope, 52 Basis, 52 Compressible Flow Vapors and Gases, 54 Factors of Safety for Design Basis, 56 Pipe, Fittings, and Valves, 56 Pipe, 56 Usual Industry Pipe Sizes and Classes Practice, 59 Total Line Pressure Drop, 64 Background Information, 64 Reynolds Number, R,. (Sometimes used Nr ), 67 Friction Factor, f, 68 Pipe—Relative Roughness, 68 Pressure Drop in Fittings, Valves, Connections Incompressible Fluid, 71 Common Denominator for Use of K Factors in a System of Varying Sizes of Internal Dimensions, 72 Validity of K Values,... 

Valves, see pipe, fittings, and valves Vapor cloud explosions, 520 Velocities, fluid flow, 85, 89, 90 Vacuum lines, 133 Velocity head, 71... 

Table 5.3. Pressure loss in pipe fittings and valves (for turbulent flow)...

As the process model is made more accurate and complicated, you can lose the possibility of obtaining an analytical solution of the optimization problem. For example, if (1) the pressure losses through the pipe fittings and valves are included in the model, (2) the pump investment costs are included as a separate term with a cost exponent (n) that is not equal to 1.0, (3) elevation changes must be taken into account, (4) contained solids are present in the flow, or (5) significant changes in density occur, the optimum diameter will have to be calculated numerically. 

ASTM A338 Malleable iron flanges, pipe fittings, and valve parts for railroad, marine, and other heavy duty service at temperatures up to 650°F (345°C) G5702... 

Industrial fermentors, as well as pipings, pipe fittings, and valves, and all parts that come into contact with the culture media and sterilized air are usually constructed from stainless steel. All ofthe inside surfaces should be smooth and easily polished in order to help maintain aseptic conditions. All fermentors (other than the glass type) must incorporate glass windows for visual observation. Naturally, all fermentors should have a variety of fluid inlets and outlets, as well as ports for sampling and instrument insertion. Live steam is often used to sterilize the inside surfaces of the fermentor, pipings, fittings, and valves. 

Ithough liquids particularly can be transported by operators carrying buckets, the usual mode of transport of fluids is through pipelines with pumps, blowers, compressors, or ejectors. Those categories of equipment will be considered in this chapter. A few statements will be made at the start about piping, fittings, and valves, although for the most part this is information best... 

Consider again Eq. (6.11). Each valve and pipe fitting is to receive an independent pipe size resistance coefficient K. A number of works have been published that derive these coefficients for every type and size of pipe fitting and valve. Proposed here is a new variable we shall call ft. Referring to the Crane Technical Paper No. 410 [10], these ft variables are given in Table 6.1. 

The following K value equations are listed for various pipe fittings and valves. All use the ft factor of Table 6.1. 

Sum the K values. Using Table 6.1, find the f value of 2-in pipe, which is 0.019. Note that Table 6.1 ft values are intended for all pipe fittings and valves. 

Step 7. Calculate the pressure drop due to acceleration or pipe fittings APA, psi. This is usually relatively small compared to the other two, APf and APe- In some cases, however, where numerous pipe fittings are involved, it can be very significant. The following equations provide the calculations required for the two-phase flow pipe fittings and valve APA losses. 

The distribution systen for pure gases and liquids is a classical example of a network system described by large and weakly non-linear systans of algebraic equations. The network comprises pipes, fittings and valves, pumps and compressors, turbines etc., and is subject to boundary conditions at the terminal inlet and outlet points. At these points, the pressure or flow or both are specified. 

FIGURE 6.5 Equivalent length of pipe fittings and valves. (Crane Co.)... 

Table 5.3. Pressure Loss in Pipe Fittings and Valves (for Turbulent Flow)...

Water is pumped into a pipe at the rate of 250 kg/hr at 950 kPa and 175°C. Because of friction in the pipe, pressure losses due to pipe fittings and valves, the pressure at the exit of the pipe drops to 760 kPa. Is the entering water liquid, vapor, or a mixture of both Determine the fraction of each. Is the exit water liquid, vapor, or both Determine the fraction of each. From the steam tables or similar source, determine the density of the overall mixture in the pipe at both locations. How many degrees of freedom exist according to the phase rule at each location ... 

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