PRESSURE TIGHT ELECTRICAL FITTING 



,_ 1" PIPE THD. 



— l"HEX /* sae thd - 



-r* 



t K 



|-t'Hfk jj'HEX 



4 SAE THD. 



->ii M — hft-* 



DRILL HOLE 

 FOR NO. 12 WIRE 





Figube 5. — Pressure-tight electrical fitting, showing machine work detail and dimensions. 



PRESSURE TIGHT FITTINGS FOR 

 REFRIGERATION TUBING 



THERMOREGULATOR FITTING 



FOR CHAMBER EVAPORATOR 



!^3 



FACE THIS SURFACE 

 WITH HARD PERMATEX 



I FITTING- SOLID 

 2- GLANO - SOLID 

 3. INNER GLAND - SPLIT 



4 SOAP STONE BUSHING - ! 



5 FOLLOWER GLAND - SPLI" 



6 NUT 



7 WASHER 

 8. LEAD GASKET 



SEAL (NO. 3) WITH 



QUICK HARDENING PERMATEX 



HEX NUT SLEEVE CONNECTION 

 O.D. OF TUBES V AND |" 

 Figure 6. — Pressure-tight fitting for refrigeration tubing. 



Facilities for Plant Growth 



For simplicity of operation, plants were grown 

 in hydroponic culture in the biosynthesis cham- 

 ber. Soil was not used because of two problems : 

 (1) maintenance of constant specific activity with 

 soil carbon dioxide being released, and (2) recov- 

 ery of roots at harvest, A uniform nutrient solu- 

 tion was used for growing each crop. This sim- 

 plified watering of the plants, because water that 

 was lost through transpiration or evaporation was 

 condensed and reused. Water was condensed 



8 



Figure 7. — Thermoregulator mounting fitting for passing 

 a large bulb thermostat through the chamber wall and 

 sealing around the small tube leading from the sensing 

 bulb to the thermostat switch. 



from the air as it contacted the cold air-condition- 

 ing coil, was passed through an ion exchanger 

 to remove dissolved metals, and was redistributed 

 to all the pots by siphon ( fig. 8 ) . 



All liquid and air service inlet valves were 

 modified from standard miniature brass body, 

 stainless steel stem valves. The valves had a short 

 nipple soldered into the inside end for connecting 

 tubing. Forty of these valves were prepared for 

 air and solution handling and were mounted in 

 the channel at the midline and in the lower angle 

 below the windows on both ends of the chamber. 



i 



