Centrifugal pump classification

Another centrifugal pump classification is whether the pump is a single-stage pump (the pressure head is developed by a single impeller) or a multistage pump (the pressure head is developed by two or more impellers). 

There are four (4) major types of pumps (I) positive displacement, (2) dynamic (kinetic), (3) lift, and (4) electromagnetic. Piston pumps are positive displacement pumps. The most common centrifugal pumps are of dynamic type ancient bucket-type pumps are lift pumps and electromagnetic pumps use electromagnetic force and are common in modern reactors. Canned pumps are also becoming popular in the petrochemical industiy because of the drive to minimize fugitive emissions. Figure 10-24 shows pump classification ... 

Reference should be made to specialist texts on pumps where classifications of pump types as a function of specific speed are presented. A centrifugal pump is suggested here. 

Basically, pump can be classified into two groups, centrifugal (or rotodynamic) pump and positive displacement pump. Positive displacement pump can be further classified into reciprocating pump and rotary pump. These are rhe pumps, which will be discussed in this chapter. See Figure 1 for the general pump classification. 

Production and Shipment. Estimated adiponitrile production capacities in the U.S. in 1992 were about 625 thousand metric tons and worldwide capacity was in excess of lO metric tons. The DOT/IMO classification for adiponitrile is class 6.1 hazard, UN No. 2205. It requires a POISON label on all containers and is in packing group III. Approved materials of constmction for shipping, storage, and associated transportation equipment are carbon steel and type 316 stainless steel. Either centrifugal or positive displacement pumps may be used. Carbon dioxide or chemical-foam fire extinguishers should be used. There are no specifications for commercial adiponitrile. The typical composition is 99.5 wt % adiponitrile. Impurities that may be present depend on the method of manufacture, and thus, vary depending on the source. 

There are three main classifications for pumps used in the chemical industry centrifugal, reciprocating, and rotary. 

The centrifugal slurry pump is the workhorse of slurry flows. Chapter 7 briefed the reader about some important slurry circuits, and it was explained that the grinding circuits consume a fair portion of the power of a concentrator. One particular pump at the discharge of the SAG, ball, or other mills is called the mUl discharge pump. Wear in these pumps is particularly harsh, leading to frequent replacement of impellers and liners, because a fair portion of the solids remain fairly coarse until recirculated back through the classification circuit. 

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