| 摘要 |
<p>A multistage evaporator 10 comprising evaporator stages 11, 12, 13 and 14 whereby liquor enters the first stage along two inlets 15 and 16 flowing to a manifold 17. The manifold 17 delivers the liquor to the underside of a bundle of 5 tubes (calandria) as represented by the circle 18 and the calandria is heated by delivery of steam/vapour to an outer jacket 19 defining a vapour space within the evaporator. The evaporator stages operate in the usual way to concentrate the liquor. The evaporator has a juice space divided in two (but could be futher divided) with the calandria in this case in two hemi cylindrical sections of tubes 10 with the whole juice space separated by a divider plate 20 which extends the full length of the evaporator effectively providing two parallel evaporator sections of the juice space fed by the selective operation of the three valves 21, 22 and 23 which are used to isolate a section for cleaning. Thus the whole of the calandria may be used which is normal operation or half operating while the other half is 15 cleaned. Regardless of whether cleaning is being carried out or not the vapour space is common to both sections of the calandria so heat is applied to both sections.</p> |
