GB1155886A - Flow Control For A Multiple-Effect Evaporator - Google Patents

Abstract

1,155,886. Evaporators, multiple-effect type. MOJONNIER BROS. CO 30 Sept., 1966. No. 43861/66. Heading B1B. [Also in Divisions G1 and G3] In a multiple-effect evaporator for concentrating liquids, such as milk, the feed liquid is delivered via line 68 (Fig. 1) to a tank 70 from which it is delivered by pump 72, constant flow unit 74 and pump 76 to a preheater 38. From the latter the liquid passes via a regenerative heater 52, final heater 60 and holding tube 78 to the inlet valve 82 of a first evaporator effect, which is of the flash/falling film type. Partial or complete recirculation to tank 70 is permitted .by valve 80. The concentrate from the first effect passes to a sump 34 therebelow from which it is delivered by pump 86 to the second effect. There are four such evaporators effects, and the final concentrate is discharged via line 20 whilst the steam and vapours are condensed at 18 after flowing through preheater 38. The steam supply to the first and second evaporators effects is from a thermo-compressor 66 and there is a supply at 64 to heater 60. The condensate from heaters 38, 60 and from the evaporators passes via line 50 to heater 52. Valve 94 allows recirculation of the final concentrate. The flow control unit 74 maintains a constant adjustable flow (see Division G2-3). Feed line 68 leads from tank 152 (Fig. 2c) which is supplied by line 176. The latter includes a valve 180 which is controlled by a float-operated pilot Valve 178 in tank 152 to maintain a constant level in the latter. When the system requires cleaning, water from tank 156 (with acid from tank 166) is supplied to tank 152 and is circulated through the heaters and evaporators, unit 74 being adjusted to allow a large flow rate of water. Valve-controlled sprays (194) are located at strategic points in the evaporators to ensure adequate cleaning.