FIG. 7E illustrates that the inlet device 15 can have a plurality of inlet apertures 15a. Although shown as three apertures 15a, more or fewer apertures 15a may be used, e.g., 2, 4, 5, 6, 7, 8, 9 or 10, for example. The plurality of inlet apertures 15a can each merge into a respective one of a plurality of inlet channels 15c. Alternatively, two or more inlet apertures 15a may merge into a shared elongate channel 15c.
FIGS. 8A-8D illustrate another embodiment of the inlet device 15. In this embodiment, the axial extent of the channel 15c is similar to the diameter of the aperture 15a. The inlet device 15 can have a planar body 15p (e.g., a relatively thin plate). The planar body 15p can have a thickness of between about 0.100 mm to about 5 mm, more typically between about 0.100 mm to about 0.50 mm. In some embodiments, the thickness can be between about 0.125 mm and about 0.30 mm, such as about 0.125 mm, about 0.150 mm, 0.200 mm, about 0.250 mm, and about 0.30 mm. The aperture 15a can have a diameter that is between about 0.01 mm and 0.150 mm, for example. In some embodiments, the axial extent or length of the channel 15c through the body of the plate 15p is about the same or no more than about 50% greater in size relative to the diameter (or maximum cross-sectional dimension for non-circular shapes) of the inlet aperture 12a (where one aperture is used) or one of the inlet apertures 12a (where more than one are used).
