Power horsepower

Power input to impeller, ft-lb/sec (see Equation 5-19) or if in a ratio can be as horsepower Power, horsepower used b impeller mixing system... 

Hp = Power, horsepower L = Effective length of key, inches RPM = Revolutions per minute Ss = Shear stress, psi Sc = Compressive stress, psi... 

Electrical Energy Requirement Compressor Power (Horsepower)... 

Energy or work calories, ergs, joules, BTU, foot pound, inch ounce, gram centimeters, newton meters Power horsepower, watts. 

Power horsepower (hp) kilowatt (kw) metric horsepower (mhp) kilowatt (kw)... 

Pot flow rate in fP /min and power in brake horsepower, a correction factor of 0.157 must be appHed to each equation. 

Typically, the power iaput ranges from W/kg (0.25—0.75 horsepower units/gal) of processed mass. Hydraulic drives, mechanical, and electronic controls are also used to achieve variation in speed of the blades for efficient processing. 

Power, P, defiaed as the rate at which work is performed, is expressed ia terms of energy divided by time and is most commonly given in units of horsepower, as for the power suppHed by mechanical devices such as diesel engines, or in the SI units of watts, especially when measuring electrical power. One horsepower is equivalent to the amount of power needed to lift 33,000 pounds (14,982 kg) one foot (30.5 cm) in one minute. One watt is equivalent to the power required to perform one joule of work per second. In a simple direct-current circuit where potential is represented by E ... 

Power. There are two main ways to measure the power deUvered by the driver to the pump. The first method is to install a torque meter between the pump and the driver. A torque meter is a rotating bat having a strain gauge to measure shear deformation of a torqued shaft. Discussion of the principle of torque meter operation is available (16). The benefit of this method is direct and accurate measurements. The power deUveted to the pump from the driver is calculated from torque, T, and speed (tpm) in units of brake horsepower, ie, BHP (eq. 4a) when Tis in lbs-ft, and kW (eq. 4b) when T is N-m. 

If the pump manufacturer uses motors for pump power measurement, these motors ate caUbrated to determine the horsepower from the electric power reading and caUbration curves. Such test motors ate recaUbrated periodically, ensuring the same degree of accuracy as shown by the torque meters. 

When arriving at the performance of a pump, it is customary to calculate its power output, which is the product of (1) the total dynamic head and (2) the mass of liquid pumped in a given time. In SI units power is expressed in kilowatts horsepower is the conventional unit used in the United States. 

Figure 10-123 shows a typical power consumption in thrust bearings as a function of unit speed. Tne total power loss is usually about 0.8-10 percent of the total rate power of the unit. New vector lube bearings reduce the horsepower loss by as much as 30 percent. In large vertical pumps, thrust bearings take not only the load caused by... 

Drive motors should be of the high-starting-torque type and selected for 1.33 times maximum rotational speed. For two- or three-diameter Idlns, the brake horsepower for the several diameters should be calculated separately and summed. Auxiliaiy drives should be provided to maintain shell rotation in the event of power failure. These are usually gasohne or diesel engines. 

Loop Reactors For some gas-hquid-solid processes, a recirculating loop can be an effective reactor. These involve a relatively high horsepower pumping system and various kinds of nozzles, baffles, and turbulence generators in the loop system. These have power levels... 

FIG. 18-42 Typical application and power for doiihle-arm kneaders. To convert horsepower per gallon to kilowatts per ciihic meter, multiply hy 197.3. [Farket] Chem. Eng. 72(18) 125 (1965) excerpted hy special pomission of the copytight owner, McGraw-Hill, Inc.]... 

When maldug any economic analysis, care should be taken to be certain that the efficiency ratings of all motors being considered are on the same basis. While this should not be a problem for motors rated 1 to 500 horsepower as covered by the NEMA Standards for efficiency marldug, it is common practice for several different test methods to be used when measuring the efficiency of motors rated over 500 horsepower. A particular test method may need to be selected by the test facility on the basis of available test equipment and power supply. All test methods that may be used to test any one motor will not necessarily give the same result for efficiency. 

The potential for power recovery from liquid streams exists whenever a liquid flows from a high-pressure source to one of lower pressure in such a manner that throttling to dissipate pressure occurs. Such throtthng represents a system potential for power that is the reverse of a pump—in other words, a potential for power extraction. Just as in a pump, there exists a hydraulic horsepower and a brake horsepower, except that in the recoveiy they are generated or available horsepowers. 

Development The following discussion relates specifically to the use of what could be called radial-inflow, centrifugal-pump power-recovery turbines. It does not apply to the type of unit nurtured by the hydroelecti ic industry for the 1 ge-horsepower, large-flow, low- to medium-pressure differential area of hydraulic water turbines of the Felton or Francis runner type. There seems to have been little direct transfer of design concepts between these two fields the major manufacturers in the hydroelectric field have thus far made no effort to sell to the process industries, and the physical arrangement of their units, developed from the requirements of the hydroelectric field, is not suitable to most process-plant applications. 

Example 2 Units for a Power Recovery System The scheme of Fig, 29-52 and the actual units supplied (Figs, 29-58 and 29-59) will he used for purposes of illustration. Since this case has the recovery unit as the sole driver, the balance point is set hy speed and horsepower. 

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