Axial pumps

BS 5316 Part 1 1976, (ISO 2548) Acceptance Tests for Centrifugal, Mixed Flow and Axial Pumps. 

The centrifugal pump operates over a very wide range of flows and pressures. For low heads but high flows the axial pump is best suited. Both the centrifugal and axial flow pumps impart energy to the fluid Iw the rotational speed of the impeller and the velocity it imparts to the fluid. 

Figure 6.10 An example of a recirculating straight open-channel design flume. The components are a = head box, b = collimator, c = open channel, d = weir, e = tail box, f = motor, g = axial pump, h = return pipe and cooling coil, and i = electric jacks. (Modified from Khalili et al., 2001.)...

Several pump-mix combinations have been developed by industry to simplify overall plant layout and minimize the number of pumps, at the expense of more expensive mixer design or complexity. The IMI axial pump-mix and draft tube (Fig. 15-55a) has the pumping... 

In this coaxial mixer, the primary role of the anchor is to clean up the wall from any accumulated solid lumps and reincorporate them back in the bulk. It also acts as a moving baffle, hampering the creation of a vortex at the liquid free surface. The purpose of the pitched blade turbine is to provide axial pumping so as to promote the resuspension of the solids, and radial dispersion to avoid solids reagglomeration. Finally, the aim of the wetting rods is to ease hydrophobic pigment incorporation by avoiding the creation of surface lumps. ... 

Turbines are a common feature on process plant, where they provide economical drives for rotating machinery, particularly centrifugal and axial pumps and compressors, as well as electrical generators in power stations. They use the expansion of hot, high-pressure gas or steam to produce mechanical power. 

Applying dimensional analysis to centrifugal and axial pumps... 

A draft tube may be used with the axially pumping impellers . 

The primaiy coolant circulation pumps are typically internal, canned axial pumps, of the glandless, vertical mixed-flow type. Some alternate IPWR arrangements have the pumps located on nozzles or "stems" attached to the lower portion of the RPV, as in the NS Otto Hahn design, and often in the cold leg of the primaiy circuit. 

Pumps force the recirculation of the coolant. Originally, an external recirculation line system was installed which, for larger plants, was then supported by internal jet pumps. In the KWU 69 and 72 designs, external recirculation was replaced by internal axial pumps operating inside the reactor pressure vessel. The KWU 72 reactor is equipped with 8 internal axial pumps at rated speed, each of these pumps has a recirculation capacity of about 8700 mVh. 

Occasionally, changes in the design of the plant effect more a reduction of personnel radiation exposure than of the contamination levels on the surfaces of the piping and components. As an example, the replacement of the external recirculation systems by internal axial pumps has to be mentioned from Fig. 4.18. the benefits of this measure can be clearly seen (Reitzner et al, 1993). 

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