Process Vacuum Supply

Redundant 28 cfm vacuum pumps located in the Zone. 1 filter room of the MER, shown in Figure 2.5-10, evacuate a 80-gallon (10.7-cubic feet) tank to supply system vacuum. The pumps are configured to automatically start to maintain system vacuum at a prescribed level. The exhaust from the pumps is routed into the Zone 1 exhaust upstream of the Zone 1 charcoal filters. Two-inch welded stainless steel piping is routed from the vacuum tank in the MER through the overhead in Rooms 112 and 111 into the Zone 2A canyon. In the canyon, the vacuum line is routed to a cold trap that will condense radioactive effluents that are drawn into the vacuum system. Two-inch welded stainless steel tubing is used to route process vacuum to each SCB. While the pumps themselves are not identified as important to safety, the routing of the pump exhaust to the Zone 1 exhaust is so identified, because it assures appropriate filtration of the effluent in the event that hazardous constituents are drawn into the system. 

Vacuum supply line from MER to Zone 2A (Transports vacuum for chemical processing.) Broken or plugged line Mechanical malfunction or worker error Control and monitoring system indications and periodic maintenance inspections None Loss of all vacuum for controlling noble gas and halogen releases and for moving process fluids. 

FIG. 18-75 Eqi lipment prices, FOB point of fabrication, for typical crystallizer systems. Prices are for crystallizer plus accessories including vacuum equipment. (Data supplied hy Swenson Process Equipment, Inc., effective Januaiy, 1.9.95.)... 

Vacuum systems are typically used when flows do not exceed 6800 kg/h (15,000 Ib/h), the equivalent conveyor length is less than 305 m (1000 ft), and several points are to be supplied from one source. They are widely used for finely divided materi s. Of special interest are vacuum systems designed for flows under 7.6 kg/min (1000 Ib/h), used to transfer materials short distances from storage bins or bulk containers to process units. This type of conveyor is widely used in plastics and other processing operations where the variety of conditions requires flexibility in choosing pickup devices, power sources, and receivers. Capital investment can be kept low, often in the range of 2000 to 7000. 

If VQ > 0, then the threshold for photoionization into a vacuum Eva( = -Ee(ls). If VQ < 0, then that additional energy has to be supplied. Delahay (1976) has summarized this process, but the actual mechanism is still debatable. If AH and Evac are experimentally known, one can get an experimental measure of the medium rearrangement energy in the ground state, EM(ls) = E - AH. On that basis, since EM is always positive, Kestner (1976) prefers the lower experimental value of AH for e. ... 

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