A __________ evaporator employs an annular downtake.

ANS:A - basket type

A basket type evaporator is a type of evaporator commonly used in the food and beverage industry for the concentration of liquid products such as juices, syrups, and dairy products. Here's an explanation of how a basket type evaporator works:

1. Basket Design: The evaporator consists of a cylindrical vessel with a perforated basket suspended inside it. The liquid to be concentrated is pumped into the basket, which holds the product during the evaporation process.
2. Heating Medium: Steam or another heating medium is used to heat the liquid in the basket. The steam is usually supplied through a jacket surrounding the vessel or through coils immersed in the liquid.
3. Evaporation: As the liquid is heated, water evaporates from the surface, leaving behind a concentrated product. The evaporated water vapor escapes from the basket through the perforations and rises to the top of the vessel.
4. Separation: The vapor rises through the evaporator vessel and is typically condensed in a separate condenser unit. The concentrated liquid product remains in the basket until the desired concentration is achieved.
5. Continuous Operation: Basket type evaporators are often operated in a continuous mode, with fresh feed continuously introduced into the basket and concentrated product continuously discharged.
6. Cleaning: The basket type evaporator is designed for easy cleaning and maintenance. The basket can be removed from the vessel for cleaning or replacement of components.

Basket type evaporators offer several advantages, including efficient heat transfer, ease of operation, and versatility for processing a variety of liquid products. They are particularly well-suited for small to medium-scale production facilities in the food and beverage industry.