Centrifugal compressor capacity control

The two principal elements of evaporator control are evaporation rate a.ndproduct concentration. Evaporation rate in single- and multiple-effect evaporators is usually achieved by steam-flow control. Conventional-control instrumentation is used (see Sec. 22), with the added precaution that pressure drop across meter and control valve, which reduces temperature difference available for heat transfer, not be excessive when maximum capacity is desired. Capacity control of thermocompression evaporators depends on the type of compressor positive-displacement compressors can utilize speed control or variations in operating pressure level. Centrifugal machines normally utihze adjustable inlet-guide vanes. Steam jets may have an adjustable spindle in the high-pressure orifice or be arranged as multiple jets that can individually be cut out of the system. [Pg.1148]

Probably the most widely used capacity control for the centrifugal compressor is speed control. The capacity curve when used with speed control covers a wide range. While electric variable speed motors offer a continuation to the speed control practice, there are some other alternatives available. Suction throttling has been widely used and offers a r sonable control range for a relatively low cost. [Pg.220]

Head coefficient, 156 Head equation, adiabatic, 3 t Head equation, poly tropic, I Head, centrifugal, 156 Head, reciprocating, 58 Heat run test (dry), 413 Helical compressor, 5, 7 adiabatic efficiency, Itil applicalion mnge, 7. ly asymmetric profile, 96 bearings, 116 capacity control, 95 casings, 114 circular profile, 95 cooling, I i 1 discharge temperature (dry), I 17... [Pg.546]

As mentioned previously, a large centrifugal compressor with a gas turbine as a driver is typically a multi-million dollar investment. A dedicated computer control system is usually employed to monitor multiple operating parameters, and that is specifically designed for the purpose. Such a control system is shown in Figure 7.27. The control of a centrifugal compressor involves the control of capacity, the prevention of surge and the protection of equipment. [Pg.171]

Induction motors are the most frequent in use because of their simple and rugged construction, and simple installation and control. They are constant speed devices available as 3600 (two-pole), 1800, 1200, and 900 rpm (eight-pole). Two speed models with special windings with 2 1 speed ratios are sometimes used with agitators, centrifugal pumps and compressors and fans for air coolers and cooling towers. Capacities up to 20,000 HP are made. With speed... [Pg.61]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...