Abstract: A flexible tube pump, reference FIG. 2, having an elastic tube 1, compounded with a magnetically responsive material, stretched onto the surface of shaft 2 to provide a seal between the contacting surfaces. A magnetic field is applied concentrically to tube 1 which expands circumferentially away from shaft 2, but only locally to the field, the region outside the influence of the magnetic field however maintains the tube 1 to shaft 2 seal. The expansion of tube 1 forms volume 7. Repetitive movement of said magnetic field in direction of arrow 6 provides moving closed volumes giving pumping action, suitable as a dry, low pressure, pump, e.g. a vacuum pump.