(一)概况 昆明市研制空心砖的历史,可追溯到五十年代后期。一九五七年,新建昆明发电厂烟囱需要用一种扇形空心砖。当时昆明地区及云南省内尚无厂家生产,向省外购买,运到昆明后,含运费在内每块砖将近合一元多,势必加大工程造价。权衡之后,决定在昆明市生产,并将此项任务交给昆明市砖瓦厂,拨给该厂试制费5000元,该厂在D30真空挤出机上研制成功,共生产了三万块。其规格尺寸如图1。 (1) Overview The history of the development of hollow bricks in Kunming City can be traced back to the late 1950s. In 1957, a chimney-shaped hollow brick was used to build the chimney of the Kunming power plant. At the time, there were no manufacturers in Kunming and Yunnan provinces. They purchased from outside the province and shipped them to Kunming. Nearly one dollar was included in each block, including freight, which would inevitably increase the project cost. After the trade-offs, it was decided to produce in Kunming City, and this task was handed over to the Kunming brick and tile factory, and the factory was allocated a trial production fee of 5,000 yuan. The plant was successfully developed on the D30 vacuum extruder and produced a total of 30,000 pieces. Its size is shown in Figure 1.