. Design and operation of a carbon-14 biosynthesis chamber. Carbon; Growth (Plants); Growth cabinets and rooms. Figtjke 8.—A schematic diagram of the chamber, showing the water recirculation equipment. ENVIRONMENTAL CONTROLS Temperature For temperature control of the room in which the chamber is located, a 10-horsepower, water- cooled air-conditioning compressor was installed in the equipment room with the cooling tower located outside the building. Two 5-ton capacity evaporator coils are located in opposite ends of the room, and the temperature is controlled by adjustable thermostats. Safety


. Design and operation of a carbon-14 biosynthesis chamber. Carbon; Growth (Plants); Growth cabinets and rooms. Figtjke 8.—A schematic diagram of the chamber, showing the water recirculation equipment. ENVIRONMENTAL CONTROLS Temperature For temperature control of the room in which the chamber is located, a 10-horsepower, water- cooled air-conditioning compressor was installed in the equipment room with the cooling tower located outside the building. Two 5-ton capacity evaporator coils are located in opposite ends of the room, and the temperature is controlled by adjustable thermostats. Safety controls turn off the lights in case the air conditioners cease func- tioning, which prevents high-temperature damage to the plants. Temperature is controlled in the biosynthesis chamber by a 34-horsepower compressor installed in the equipment room and an evaporator coil in the chamber. A large-bulb thermostat controls a solenoid in the liquid Freon line, and the com- pressor is operated on back-and-head pressure controls. Temperature in the chamber is main- tained within ±° F. A 500-watt strip heater is operated continu- ously in the chamber to increase the heat load for the compressor to reduce humidity. Lighting The biosynthesis chamber is illuminated by a bank of 80 fluorescent 96-inch tubes and 24 incan- descent 60-watt lamps. These produce a light intensity in excess of 1,000 foot-candles at the floor of the chamber. Readings of about 1,500 foot-candles at the horizontal midline and be- tween 2,500 and 3,000 foot-candles at the top inside the chamber have been observed. These values are sufficiently high to give excellent growth of soybeans, wheat, corn, and tobacco. The controls for the lighting and refrigeration are installed in the machinery room. The ballasts for the fluorescent lights are mounted on a rack and covered with a vented hood. A thermostati- cally controlled exhaust fan removes excess heat. Carbon Dioxide Radioactive carbon (C-14) is available at mo


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Keywords: ., bookauthorunitedstatesdepartmentofagriculture, bookcentury1900