Other Designs

Perkin-Elmer (now PerkinElmer) (PE) Corporation designed several types of tilt-compensated interferometers for their FT-IR spectrometers. All of these interferometers operate on a similar principle, which was first described by Sternberg and James in 1964 [22]. In these interferometers, two or more mirrors are mounted on a common base plate which is rotated to give rise to the path difference in two arms of the interferometer. 

In an excellent paper [23], Kauppinen et al, discuss a series of related interferometers in which complementary reflections from two flat mirrors in each arm 

A successM variant of this principle where the OPD is introduced by rotating a refractive element has been designed by Mold and Tlimer of PerkinElmer Ltd. [24,25]. When tested in comparison with several other tilt-compensated interferometers, this instrument had better resistance to the effects of tilt and shear than that of any other instrument tested. For example, the modulation efficiency of this interferometer in the near infrared did not change by more than 0.1% when the temperature was changed by more than 5°C [26]. This instrument has one fairly important disadvantage, however, in that it is far more expensive instrument to build than competitive designs and has not been introduced commercially. 

000 rpm are possible with this instrument, enabling up to 1000 scans per second to be measured in principle. In its current manifestation, the infrared and laser inter-ferograms are sampled simultaneously at 4 MHz, so that 6-cm resolution spectra are measured once every 5 ms, the speed of the ADC being the main factor that limits the rate at which interferograms can be acquired. Since advances in ADC technology are made every year, it seems only a matter of time before this instrument will be able to measure 1000 scans per second. 

Maintaining accurate positioning of the prism over the entire length of a scan required to yield a 1-cm resolution spectrum presented a real problem in stability. The base of the interferometer had to be constructed of granite and the optical carrier was made of stainless steel and invar, the low-expansion coefficient of which is close to that of granite and quartz. Nonetheless, the sensitivity of measurements of extended sources made with this type of interferometer could be up to 20 times 

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Other designs of kilns use static shells rather than rotating shells and rely on mechanical rakes to move solid material through the reactor. 

If the distillation column will not fit either above or below the pinch, then other design options can be considered. One possibility is... 

Other designs squee2e the cake between two permeable belts or between a screw conveyor of diminishing diameter, or pitch, and its permeable enclosure. The available filters which use mechanical compression can be classified into four principal categories, ie, membrane plate presses, tube presses, belt presses, and screw presses. 

Failure Cause. The failure cause is the physical, chemical, electrical, thermal, or other design deficiency which caused the failure. The agent, physical process, or hardware deficiency causing the failure mode must be identified, ie, what caused the failure for each failure mode. There may be more than one cause. Failure Fffect. The failure effect is the local effect on the immediate component/subsystem and the global effect on system performance/operation. In commercial products, the effect on the customer, ie, the global effect, must be addressed. 

In other designs, a diffused siUcon sensor is mounted in a meter body that is designed to permit caUbration, convenient installation in pressure systems and electrical circuits, protection against overload, protection from weather, isolation from corrosive or conductive process fluids, and in some cases to meet standards requirements, eg, of Factory Mutual. A typical process pressure meter body is shown in Figure 10. Pressure measurement from 0—746 Pa (0—3 in. H2O) to 0—69 MPa (0—10,000 psi) is available for process temperatures in the range —40 to 125°C. Differential pressure- and absolute pressure-measuring meter bodies are also available. As transmitters, the output of these devices is typically 4—20 m A dc with 25-V-dc supply voltage. 

Several descriptions have been pubUshed of the continuous tar stills used in the CIS (9—11). These appear to be of the single-pass, atmospheric-pressure type, but are noteworthy in three respects the stills do not employ heat exchange and they incorporate a column having a bubble-cap fractionating section and a baffled enrichment section instead of the simple baffled-pitch flash chamber used in other designs. Both this column and the fractionation column, from which light oil and water overhead distillates, carboHc and naphthalene oil side streams, and a wash oil-base product are taken, are equipped with reboilers. 

Mineral species Other designations Main producers Wodd production, 1988, %... 

Fig. 4. Specific properties of reinforcing fibers for composite materials. K-29 and K-49 represent Kevlar aramid fibers. Other designations are explained...

Both Mitsubishi and Mitsui TLEs differ drastically from other designs. Mitsubishi offers a TLE with an integral steam dmm and cyclone for vapor—hquid separation. The pyrolysis gas flows in the shell side, and is claimed to accomplish the decoking of the furnace and the transferline exchanger in one operation. The Mitsui quench cooler uses three concentric tubes as the tube element, and requires steam—air decoking to clean the TLE (58,59). 

TEMA-style shell-and-tube-type exchangers constitute the bulk of the unfired heat-transfer equipment in chemical-process plants, although increasing emphasis has been developing in other designs. These exchangers are illustrated in Fig. 11-35, and their features are summarized i n Table 11-11. 

Most of the analytical treatments of center-fed columns describe the purification mechanism in an adiabatic oscillating spiral column (Fig. 22-9). However, the analyses by Moyers (op. cit.) and Griffin (op. cit.) are for a nonadiabatic dense-bed column. Differential treatment of the horizontal-purifier (Fig. 22-8) performance has not been reported however, overall material and enthalpy balances have been described by Brodie (op. cit.) and apply equally well to other designs. 

A basic stirred tank design is shown in Fig. 23-30. Height to diameter ratio is H/D = 2 to 3. Heat transfer may be provided through a jacket or internal coils. Baffles prevent movement of the mass as a whole. A draft tube enhances vertical circulation. The vapor space is about 20 percent of the total volume. A hollow shaft and impeller increase gas circulation (as in Fig. 23-31). A splasher can be attached to the shaft at the hquid surface to improve entrainment of gas. A variety of impellers is in use. The pitched propeller moves the liquid axially, the flat blade moves it radially, and inclined blades move it both axially and radially. The anchor and some other designs are suited to viscous hquids. 

The surface area of a spill should be minimized for materials that are highly toxic and have a significant vapor pressure at ambient conditions, such as acrylonitrile or chlorine. This will make it easier and more practical to collect vapor from a spill or to suppress vapor release with foam. This may require a deeper nondrained dike area than normal or some other design that wilfminimize surface area, in order to contain the required volume. It is usually not desirable to cover a diked area to restric t loss of vapor if the spill consists of a flammable or combustible material. 

Despite the use of explosion-pressure-resistant equipment for the full explosion pressure or other design measures outlined later, everything possible must be done to prevent effective ignition sources, because loss of product and interruption of production are equally undesirable. 

Figure 2.7 Other designs of a few double cage slots...

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