Abstract: A transporter includes at least one elongated transporting element (1) which is made of a material capable of changing its volume in response to the application of voltage or magnetic fields thereacross. The transporting element, optionally together with a further transporting element or some other part of the transporter, defines an elongated transporting channel (7). Means are provided for generating fields in predetermined regions along the transporting element (1) and in a given order of sequence, such as to impart substantially peristaltic motion to the element. These means include at least three mutually adjacent conductors (3, 4, 5) which extend substantially helically in relation to the transporting element (1) and to which different phases of a multi-phase alternating voltage or alternating current source are applied.