Rotating racks

Rack ovens have central rack which is rotated around a vertical pivot (Figures 8 and 9). The rack accepts trays of products. The rotating rack evens out the flow of heat to the products. As the rack rotates hot air is blown over the products so that a very even heat distribution is obtained. Some rack ovens are equipped to blow steam over the product, either to give crisp baguettes or to steam products like Christmas puddings. 

The temperature within our oven was controlled by a multielement air heater and proportional energy input control. Fluctuations were within =t0.5oC. and the samples were mounted on a rotating rack. To accelerate the aging, very thin specimens were used. In fact, the first goal... 

In addition to the reactor core, several irradiation facilities are shown a rotating rack for 40 samples with a tube of access to these irradiation positions, a pneumatic tube, and a central irradiation tube. The neutron flux at a typical nominal power of 100 kW amounts to 4 X 10 s cm in the central irradiation tube. The ionization chamber shown allows for a measurement of the neutron flux (the reactor power). 

Rotating racks for adhesive jumbo rolls in a temperature-regulated storage hall (Photo tesa Werk Offenburg)... 

Screening. A 100-g sample of mica is usually used for this test, plus a rack of six Tyler sieves and a pan. The stack of sieves containing the sample is rotated, and after screening, the mica remaining on each screen is weighed and the percentage retained is calculated. A combination of wet and dry screening may also be used to determine particle size distribution of fine mica (<0.147 mm ( — 100 mesh)). 

When the fuzed bomb is dropped, the arming wire is retained in the bomb rack in order to free the arming vane assembly, thus causing it to rotate in the airstream. After traveling thru the air at a predetermined distance, the arming of delay mechanism is completed and further rotation unscrews the arming mechanism from the fuze... 

In the old CT unit, the detectors are stationary in a particular view and the collimators move by a desired angle to obtain projections for various chords. The intensity of radiation as detected by the detectors is not uniform it is maximum when the collimator passes the center of the detector and minimum at the two edges. To overcome this non-uniformity in the new setup, the collimator position has been fixed at the center of the detector and the whole detector-collimator rack is rotated (Fig. 3a). 

In a recent experiment, translational and rotational motion of a single molecule was driven and monitored by the STM tip at 7 K in a sort of rack-and-pinion device.67 The pinion consists of a 1.8 nm diameter molecule acting as a six-toothed wheel interlocked at the edge of a self-assembled molecular island functioning as a rack. The rotation of the pinion molecule tooth by tooth along the rack could be monitored owing to the presence of a chemical tag attached to one of its cogs. 

The holder for the work piece or pieces consists essentially of a metal rack or jig, on which the articles can be held by means of clips or other such accessories it may be used stationary, or in more elaborate forms with rotary or planetary movement in such cases the drive is by means of an electric motor mounted externally on the chamber, with the shaft led into the chamber through a vacuum-tight seal. Planetary movement of the work holder in particular requires further description typically, the articles are clipped to individual cages (called planets ), which are attached to the main frame of the holder. The frame is driven and by means of gearing and inter-connecting drive chains the planets in turn can be made to rotate in a selected ratio to their speed of rotation (the usual ranges of ratios are from 5 1 to 10 1). 

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