Wiped Film Still Components Part I – General Overview of a Wiped Film Still

At its core, a wiped film still is very simple.  A wiped film still is a vertical cylinder made of steel or glass (or exotic metal) whose outside can be heated.  The material to be distilled is fed into the still body at the top of the cylinder.  The material runs down the inside of the cylinder and is wiped into a thin film by the wipers that are fixed inside the cylinder.  These are run by an overhead motor that seals to the top of the still body. 

The material that is volatile evaporates from the still body, and the rest of the material runs out of the still at the bottom.  This material, the heavy or non-volatile material, is known as the residue.  The vapors condense on a condenser and are collected as distillate.  Heat is applied to make the distillation happen on the outside of the cylinder, and a vacuum system is attached to the still to provide the desired vacuum to drive the distillation.  The material is fed into the still at a continuous rate, creating a continuous distillation, where material is constantly entering and exiting the still body.  This is wiped film distillation.

That said, let’s dive into a detailed description of the wiped film still.  In this series we will talk about the nuts and bolts of the system.  Gaining an understanding of each piece of the equipment will help in understanding how they work.

Wiped film still systems can be configured as complicated or as simply as desired.  However, at their core, they are a very simple and incredibly efficient evaporation system.

A wiped film still system consists of the following components:   feed system, still body, condensers, wiping system, still heating system, distillate and residue collection systems,  cold trap, vacuum system and digital control systems.

This series will feature a post on each of these components, fully explaining them in detail.