Trap Sizing

To traps, 0.2 psi/100 ft. From bucket traps, size on the basis of 2-3 times normal flow, according to pressure drop available. From continuous drainers, size on basis of design flow for 2.0 psi/100 ft... 

Fig. 8.8. Schematic illustration of the electrode structure of an antiproton catching and cooling trap. The dimension shown is approximate and is illustrative of the trap size used by Holzscheiter et at. (1996).

Select the trap size based on the load and steam pressure. Obtain a chart or tabulation of trap capacities published by the manufacturer whose trap will be used. Figure 6.8 is a capacity chart for one type of bucket trap manufactured by Armstrong Machine Works. Table 6.15 shows typical capacities of impulse traps manufactured by the Yarway Company. Be sure to use up-to-date vendor data. 

To traps, 0.2 psi/IOOft. From bucket traps, size on the basis of 2-3... 

Trap size is limited only by the materials on hand, since scientists haven t yet decided exactly what is too big or "too small. Naturally, larger traps will catch more pests. Commercial traps are available in a range of sizes from 3" X 5" and up. Long, narrow, rectangular, or oval shapes may attract the most pests. 

Sizing to include potential startup loads leads to oversizing in thermodynamic traps. A thermodynamic trap will handle a great deal more cold condensate than hot condensate and if a still greater rate is desired, the line can be manually blown down. For applications other than steam tracing, careful consideration should be given before introducing any startup allowance, especially if the addition requires an increase in trap size. 

For steam tracing applications, a flow rate of 100 pounds per hour gives the best balance between trap sizing and traced length of pipe. The allowable lengths at various temperatures stays within the realm of possibility while the unavoidable short runs do not cause the flow rate to fall into the trap s inefficient range. 

It is not easy to machine traps of such a small design and to retain the ideal hyperboloidal form. In addition, optical beam access becomes very restricted, when the trap size is diminished. Fortunately, millimeter-scale ion traps are well suited to store the particle in a very small volume (that is, of the dimension of the wavelength). In the region close to the center of the device, the conditions to obtain a quasi-pure quadrupole field are not too constraining. The goal consists essentially to realize a small trap, the geometry of which enables the creation of a suitable confinement field, and with a structure sufficiently open to permit illumination of the ion in the trap and efficient collections of photons emitted by the single atom. 

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