Reciprocating motion

Reciprocating Screens These screens have rnanv applications in chemical work. An eccentric under the screen supplies oscillation, ranging from gyi atoi-v [about 0,05-m (2-in) diameter] at the feed end to reciprocating motion at the discharge end, Freqiiencv is 8 to 10... 

Glycol powered pumps are inexpensive and easy to repair in the field. They have many moving parts and because of their slamming reciprocating motion require constant attention. One spare pump should always be installed. 

Figure 11-10. The croMheod converls the rotating motion of the connecting rod to 0 linear, reciprocating motion, which drives the piston. [Courtesy of Dresser-Rand Company.)...

Wechsel-bewegung, /. reciprocating motion, -beziehung, /. correlation interrelation ... 

Such a reciprocal motion of the kinetic chain (or back reaction) results in the decomposition of hydroperoxide groups without any interruption of kinetic chains and leads to the decrease in hydroperoxy groups. It has... 

The reciprocating motion of the piston is transformed into rotaiy motion on the crankshaft by two of the links in the slider-crank mechanism—the connecting rod and the crank (hidden from view in this cross section). The connecting rod joins the piston pin to the crank pin. The crank connects the crank... 

In the compression ignition cycle, the air is compressed and the fuel is injected into the compressed air at a temperature sufficiently high to spontaneously ignite the fuel. The heat released is converted to mechanical work by expansion within each cylinder and, by means of the reciprocating motion of the piston, is converted to rotary motion at the crankshaft. 

The compressing and displacing element (piston or diaphragm) has a reciprocating motion. The piston... 

Time-domain plots must be used for all linear and reciprocating motion machinery. They are useful in the overall analysis of machine-trains to study changes in operating conditions. However, time-domain data are difficult to use. Because all the vibration data in this type of plot are added together to represent the total displacement at any given time, it is difficult to directly see the contribution of any particular vibration source. 

Few machines involve linear reciprocating motion exclusively. Most incorporate a combination of rotating and reciprocating linear motions to produce work. One example of such a machine is a reciprocating compressor. This unit contains a rotating crankshaft that transmits power to one or more reciprocating pistons, which move linearly in performing the work required to compress the media. 

If a rapid, reciprocating motion of relatively short amplitude is applied to the liquid contents of an extraction column, the column is said to be pulsed. The agitation thus provided has been found to give improved extraction rates. Devices of this sort were suggested as early as 1935 (VI), but it was not until the atomic energy programs in the United States and Great Britain developed a need for efficient extractors of low... 

It is especially difficult to seal pistons with reciprocating motion. Piston rings are suitable as piston seals in piston compressors up to 1500 bar. Above 200 bar, lubrication is generally required. 

A rapid reciprocating motion imparted to the liquid in a tower results in improved mass transfer. This action can be accomplished without parts and bearings in contact with the process liquids and consequently has found favor for handling hazardous and corrosive liquids as in nuclear energy applications. Most of the applications still are in that industry, but several other installations are listed by Lo et al. (1983, pp. 345, 366). Packed columns up to 3 m dia and 10 m high with throughputs in excess of 200 m3/hr are in use. 

Desirable motion can be imparted to the liquids by reciprocating motion of the plates rather than by pulsing the entire liquid mass. This mode employs much less power and provides equally good extraction efficiency. A 30 in. dia tower 20 ft high is sufficiently agitated with a 1.5 HP motor. Some arrangements of such extractors are shown in Figure 14.13. 

Oscillating motion of the conveyer causes reciprocating motion of the material which is unloated at the upper point of the conveyer. The granules are cooled and dried by clod air supplied by the fan. Thecooling air temperature iscontrolled within 20-40 °C. 

Chatter, simmer or flutter Abnormal, rapid reciprocating motion of the movable parts of a PRV in which the disc makes rapid contacts with the seat. This results in audible and/or visible escape of compressible fluid between the seat and the disc at an inlet static pressure around the set pressure and at no measurable capacity, damaging the valve rapidly. 

Chatter The abnormal rapid, reciprocating motion of the movable parts of a pressure relief valve in which the disk contacts the seat. 

Figure 6.21 illustrates a cell that is useful for the circulation of an electroactive gas through a solution.66 Such a system is particularly desirable when the supply of gas is so limited that it cannot be continuously bubbled through the solution. The gas is pumped by means of a loosely fitting Teflon-coated piston that is driven with a reciprocating motion by an external magnet. 

Reciprocating sieve-plate columns, where a reciprocating motion is imparted to the plate assembly, have been suggested by Karr and Lo (1976). In such columns, a baffle plate can be employed to minimize axial mixing, and reciprocation speed can be varied over a wide range. Karr and Lo have discussed procedures for scale-up and have tested this procedure with columns up to 90 cm in diameter. HETS increases with column diameter and shows an optimum with respect to reciprocation speed. For a column 90 cm in diameter,... 

The reciprocating bioreactor is a slim cylindrical vessel with a height/ diameter ratio of the order of 4 to 5 (Brauer and Sucker, 1979). The reactor contains a package of sieve plates attached to five rods. In the reactor of Brauer and Sucker (1979), the plate spacing is 42 mm, the diameter of the holes in the plates is 12 mm, and the hole spacing is 29 mm. This element undergoes a reciprocating motion up and down the reactor with an amplitude of 100 mm. 

The reciprocating motion of the sieve plate generates vortices in the biosuspension. Each vortex region represents the elementary volume of the bioreactor. When the gas dispersion element moves upwards, the biosuspension is forced to pass through the holes of the sieve plates From each hole, a jet of biosuspension flows downward into the space between two sieve plates. The jet reverses direction as the element reverses direction. Very effective dispersive action is due to the periodic generation of bubbles, which renews the larger interfacial area on each reversal of direction. The important design characteristics of this reactor are summarized in Table XXV. 

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