Process for the production of bulked and crimped yarn

A method of producing bulked and crimped yarn of substantially constant quality by the use of a bulking and crimping device of the type incorporating means arranged to receive yarn and propel it forwardly so as to form an elongated package extending in a direction away from the receiving and propelling means, the yarn being added to one end of the package and being taken off from the other end of the package in a bulked and crimped state, comprising sensing the deviation of the position of the take-off end of the package from a predetermined datum position, generating a signal containing information about the magnitude of the said deviation and using said signal to control the temperature of the yarn being fed to the package so that the temperature of the yarn is a function of the deviation of the position of the take-off end of the yarn package from the predetermined datum position.