DEVELOPMENT IN TANGENTIAL MIXERS Through extensive experience in the repair and overhauling of mixers, Carter Bros observed a number of ways in which the design of tangential rotor mixers could be enhanced. This has given rise to the introduction of a wider tip rotor which the company builds into its own mixer units or which can be supplied as part of a retrofit package. Customer experience indicates highly favourable results with benefits including low power consumption and better mixing characteristics. Without the invention of the tangential type mixer in the early part of the 20th century, the mixing of rubbers may well have developed in a very different way. It is true that many companies around the turn of the century were making machinery for the mixing of rubbers, as a brief study of the books and papers by Professor James White1,2 and others indicate. Since the time when patent protection of the tangential type mixer ceased, many mixers working on similar principles have been designed. Some of these are based directly on the original design, as some manufacturers previously had licences to produce this machine. Others, such as the Carter mixers, have been designed from experience and knowledge gained by repairing and overhauling internal mixers over many years. This experience has allowed an open-minded view of mixer design, which is not always so easy when a particular design has been historically invented by, or licensed, to a company.