274. The area indicated by the letter «L» of the device shown in the illustration is properly called the __________

The injection chamber (choice D) is the lower space that receives operating water to actuate the sliding bowl bottom. This chamber, located directly below the sliding bowl bottom, is specifically designed to receive injected water and lift the bottom, opening discharge ports. The operating water reservoir is a separate storage area, and 'pre-injection chamber' and 'channeling chamber' are not standard terms for this function.