Interlocks centrifuges

Gas pressurized Monitor tank level and provide interlock for feed feed shut-off overpressurizes, alternate fluid delivery system (e.g., pump) centrifuge system when feed vessel delivery gas pressure to maximum safe empties working pressure of downstream system (e.g., pressure regulation) Restrict feed flow rate to be consistent with vent capacity Ensure adequate vent capacity for maximum possible gas flow ... 

Blockage of liquid Monitor pressure drop across vent system (e.g., effluent line due local indication, alarm or interlock) to closed valves,, Interlock valve in feed line to centrifuge results in flooding of basket and Equipment/line-up checks overflow from Remove unnecessary valves basket to solid col-. 5, lection system in base. Possibility of liquid spill. ... 

Interlock so that it is not possible to operate centrifuge if lids and/or inspection ports are open... 

Liquid feed con- Interlock feed to bowl rotation tinues after basket of centrifuge stops spinning. ... 

An interlock is provided through a centrifugal type of pressure switch (PS) to trip the engine in the case of low lube (lubricating) oil pressure during a run. Since during a. start oil pre.s.sure has not built up, a timer, 7 j is introduced to bypass the trip interlock and avoid a false trip. A relay (contactor), d], is used to provide lube oil pressure interlock. 

There are trade-offs for magnetic drive and canned pumps versus centrifugal pumps with double-mechanical seals. The former have no seals to leak, but need active interlocks to prevent high temperature for temperature sensitive materials. Similarly, diaphragm pumps, that have... 

Complex interlocks required for large complex equipment such as large compressors, centrifuges, kilns, etc. ea 4,100 200... 

The maximum speeds of basket centrifuges with cake discharge filter bag pullout or manual digging vary from 1200 to 2100 rpm (some have two-speed drives), and basket diameters are in the range from 500 to 1250 mm. A 1200 mm diameter, 750 mm long basket may handle as much as 200 kg of cake in one charge. Interlocks and inert gas blanketing may be used. 

Swirling of liquid or slurry inside the centrifuge is one frequent cause of imbalance. Introducing the feed at the proper rate during acceleration is the best way to avoid this. Under no circumstances should feed begin before the rest of e system is ready to accept and process it. When the centrifuge is instrumented, interlocks are required. 

Fig. 13.12 Centrifuge with two interlocking switches closed in the run mode.

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