Centrifugal pumps electric motors

Most rotating equipment includes electric motors or steam dryers that generate noise at a constant frequency. Air cooler fans are a source of noise that can be reduced by lowering the fan speed and increasing the number of blades. Pump motor noise can be reduced by including a shroud or fan cover that is accurately lined. Centrifugal compressor noise reduction can be achieved by blade design and the use of compressor pulsation noise reduction, silencers, and vibration isolation. 

Piping and pumps used for transfer of the butanols can be made of the same metal as tanks. Centrifugal pumps with explosion-proof electric motor drives are recommended (34). 

The centrifugal pump directly driven by a variable-speed electric motor is the most commonly used hardware comoination for adjustable speed pumping. The motor is operated by an electronic-motor speed controller whose function is to generate the voltage or current waveform required by the motor to make the speed of the motor track the input command input signal from the process controller. 

Example 2 Vibration Consider an electric motor rotating at 1800 rpm driving an 8-vane centrifugal pump rotating at 600 rpm. For this 3 1 speed reduction, assume a gear box having two gears of 100 and 300 tooth. Since 60 Hz is 1 rpm,... 

Applications include electric motor drives for conveyors and other material handling equipment such as stacker reclaimers, crushers, haulages, ball mills, cranes, hammer mills, rotary dryers, centrifuges, reciprocating pumps, winches, fans and wire drawing machines. 

No matter the duty (utilities excepted), most boiler plant systems employ electric motor-driven, single-stage or multistage centrifugal pumps to supply FW. These may be of conventional design or derivations such as a turbine pump. However, steam-driven reciprocating FW pumps (steam pumps) are still employed in some countries and for certain smaller applications. 

The nature of the power supply. If the pump is to be driven by an electric motor or internal combustion engine, a high-speed centrifugal or rotary pump will be... 

For the designer, the use of a standardised component size allows for the easy integration of a piece of equipment into the rest of the plant. For example, if a standard range of centrifugal pumps is specified the pump dimensions will be known, and this facilitates the design of the foundations plates, pipe connections and the selection of the drive motors standard electric motors would be used. 

Example 13.4 A centrifugal pump is required to deliver 100 m3 of water per hour with an increase in pressure of 5 bar. If the driver for the pump is to be an electric motor with an efficiency of 90%, electricity costs 0.06 KW h-1, operating for 8300 hours per year, estimate the annual cost of power. 

Electric motors are frequently used to drive small piston pumps that prime the main centrifugal pumps. 

A steam turbine is a machine with an ancient genealogy. It is a direct descendant of the overshot water wheel, used to kick off the industrial revolution in England, and the windmill still used in Portugal. Turbines are widely used in process plants to drive everything from 2-hp pumps to 20,000-hp centrifugal compressors. They are versatile machines, in that they are intrinsically variable-speed devices. Electric motors are intrinsically fixed-speed machines. It is true that there are a variety of ways to convert AC (alternating-current) motors to variable speed, but they are all expensive and complex. 

There are two general types of steam turbines extraction and condensing. The most common turbine with which the process operator comes into contact is used to spare an electric-motor-driven centrifugal pump. The three-phase, AC motors used in the United States and South America are either 1800 or 3600 rpm. The motors used in Europe are 1500 or 3000 rpm. Small steam turbines (20 to 500 hp) used to drive centrifugal pumps, are rated for the same speed as the electric motors that are used in that particular service. 

Process pump modular cost. Figure 8.8 reveals centrifugal pump cost, including both pump and electric motor driver. This cost figure is for 2001. These are general-purpose process pumps of API standard speci-... 

Part of the chemical manufacturing complex in Tennessee had been shut down, was idle, and there was no immediate intent to restart it. Some equipment had not yet been drained and washed. The system included a 50% sodium hydroxide (caustic soda) tank and the associated centrifugal pump. The pump was an ordinary 1750-rpm pump, driven by a 10-hp electrical motor. Both the suction and discharge manual block valves on this caustic pump were closed. However, the breaker box was still energized. [12]... 

Type of power supply. Rotary positive-displacement pumps and centrifugal pumps are readily adaptable for use with electric-motor or intemal-combus-tion-engine drives reciprocating pumps can be used with steam or gas drives. 

Figure 14-37 gives values that are suitable for design estimates of centrifugal-pump efficiencies. Because pump and driver efficiencies must both be considered when total power costs are determined, necessary design data on the efficiency of electric motors are presented in Fig. 14-38. 

Mixed acid and glycerine are stored externally in separate tanks and are transferred by means of centrifugal and gear pumps to small feed tanks. From the feed tanks the reactants are sent to the nitrator by means of two positive displacement pumps driven by the same electric motor. Two speed variators allow change in the total flow rate as well as the ratio between acid and glycerine. The glycerine feed pipe in the nitrator, fitted with a multi-nozzle distributing head is... 

Pumps.—Boiler-feed pumps are of the plunger (direct-steam or power-driven) or rotary (centrifugal) type the latter being driven by a steam turbine or electric motor. Steam-driven pumps are used when there is need of their exhaust for feed-water heating. Centrifugal pumps are generally more compact, and easier to maintain than plunger pumps. 

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