Conical pipe connection

Figure 12.18 Conical pipe connection (a) typical standard cone-type seal (DN1.6-DN4.76, PN4137) (b) details oftu be end (tube outside diameter = 6.35-14.3 mm) (c) details of sealing [22].

An example of an agitated vessel in which compressed air is used is the Pachuca tank, shown in Figure 10.8. This is a cylindrical tank with a conical bottom, fitted with a central pipe connected to an air supply. Continuous circulation is obtained with the central pipe acting as an air lift. Additional air jets are provided in the conical portion of the base and are used for dislodging any material which settles out. 

Venturi Meters The standard Herschel-type venturi meter consists of a short length of straight tubing connected at either end to the pipe line by conic sections (see Fig. 10-15). Recommended proportions (ASME PTC, op. cit., p. 17) are entrance cone angle Oti = 21 2°, exit cone angle Cto = 5 to 15°, throat length = one throat diameter, and upstream tap located 0.25 to 0.5 pipe diameter upstream of the entrance cone. The straight and conical sections should be joined by smooth cui ved surfaces for best results. 

A well point system consists of several individual well points spaced at 0.6 m to 1.8 m intervals along a specified alignment. A well point is a well screen (length 0.5 to 1.0 m) with a conical steel drive point at bottom. Individual well points are attached to a riser pipe (diameter 2.5 to 7.5 cm) and connected to a header pipe (diameter 15 to 20 cm). At the midpoint, the header pipe is connected to a centrifugal pump. As yield at different well points may vary, a valve at the top of each riser pipe is used to control the drawdown so that the screen bottom is exposed. The pump provides 6 to 7.5 m of suction, but friction losses reduce the effective suction to 4.5 to 5.4 m. 

This includes orifice plates, ISA nozzles, conical inlets and venturi tubes, all of which depend on the measurement of the pressure drop across a restriction through which the whole of the flow is passed. Figure 11.10 shows a sketch of a typical orifice meter which consists of a concentric square edged circular hole in a thin plate, which is clamped between the flanges of the pipe. The minimum section of the stream tube occurs downstream from the orifice with the formation of a vena contracta at section 2. A typical connection would be one diameter... 

Zg—distance from the conic dissector to an irrigation connecting pipe, m ... 

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