Cooling hinges

HoUow mol ding as the name implies is a molded product with a hoUow center such as Easter eggs, bunny rabbits, and Santa Claus. The molds used in hoUow mol ding are divided in two halves and connected by a hinge. Chocolate is deposited into one half of the mold. The mold is then closed and rotated so that the Uquid chocolate completely coats the inside surface of the mold. After cooling the molds are opened and the piece removed. 

Hinged louvers actuoted by height of pellets in column Cool oir in... 

Close the hinged cap on the dropping bottle and immediately remove the bottle from the hot water. Cool the bottle by immersing it in another 1000-mL beaker containing tap water. 

The helium supply seemed secure, but then scientists discovered a whole new application for the gas. Helium boils at the lowest temperature of any substance (-269°C) and it never solidifies. Liquid helium is therefore the ideal substance to cool electrical wires and reduce their resistance to the flow of the current. It has allowed us to manufacture superconducting magnets, which have diverse applications, but probably none more useful than in magnetic resonance imaging. This technology affords doctors a noninvasive look inside the human body, and it Is probably the most important medical diagnostic tool ever developed. The future of mri, however, hinges on the availability of helium. Think about that the next time you fill those birthday balloons with the gas. 

On the cathode side, on the other hand, the primary purpose of gas purge is to remove water from the cathode compartment, particularly in preparation for cold start from subzero temperatures. As gas purge defines the initial condition of water distribution in a cell, it is a crucial step in PEFC cold start. Recent experimental studies have amply shown that not only performance but also material durability of PEFC hinges strongly upon the gas purge process prior to cool down and cold start. This is because an effective gas purge can remove water from the catalyst layer and membrane, thereby creating space for water produced in cold start to be stored. 

The apparatus (Fig. 9) consists of a 50-ml. flask A sealed to a 30-mm. p3rrex tube B 66 cm. long through the center of which passes tube C, 8 mm. in diameter. Cold water is conducted through this by means of a 4-mm. tube D. The apparatus is so placed in a 33-cm. hinged-type electric furnace, slightly tilted, that the end of the cooling tube is at the center of the furnace. 

When the plastic melt flows across the small hinge gap, frictional heat will be generated. There should be sufficient cooling of the mold around the hinge area. 

In a practical sense, enclosure designs often require some accommodation. For ease of maintenance, enclosures can be constmcted to rise upward and away from the machinery by overhead cranes. Access openings can be provided by tunnels lined with acoustically absorbent material (in effect, mnfflers). Access for controls can be designed with hinged covers that lift easily, or the controls can be relocated. Some enclosure panels can be lifted automatically at the correct point in the machine cycle to provide access. Ducts can be provided with small ventilating fans to prodnce a controlled cooling airstream and, if combined with filters, can allow a controlled environment for some operations. 

In Illustration 7.9 it was tacitly assumed that the product compositions and operating pressure of the column were given, or at least easily specified. The common conception is thaf these parameters are determined either by market demand — the customers wants a certain pimty—or by the obvious desire to maximize recovery and minimize cost. In actual fact, they often hinge on quite different and mundane factors, such as the quality of available steam or the exit temperature of the cooling medimn. The chemistry of the system often intrudes as well, sometimes in unexpected ways. 

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