| 摘要 |
The temperature of bakery products is reduced immediately after the discharge thereof from the oven, by means of vacuum, by first subjecting the bakery products to a substantially linear pressure reduction as a function of time at a rate of not more than 60 mm Hg per second through at least half of the total pressure drop to be achieved. The pressure reduction rate is then allowed to increase substantially for a terminating vacuum treatment. At least one vacuum chamber is provided and is adapted to be connected to a source of vacuum through a vacuum conduit and a valve, and has a closeable opening for bringing bakery products into and out of the chamber. In the vacuum conduit, in parallel to a servo-valve serving to apply a full vacuum effect from the source of vacuum during the remaining portion of the total pressure drop, there is inserted a by-pass conduit having a permanently open cross-section which can be adjusted to provide the substantially linear pressure reduction.
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