The invention relates to a pump which comprises a tube ( 4 ) through which a fluid is delivered, and a device ( 2 ) for producing transverse oscillations in the fluid. On the inlet side ( 5 ), the tube ( 4 ) has a first section ( 1 ) with an invariable delivery cross-section and on the outlet side ( 6 ) a second section ( 3 ) with a variable delivery cross-section. The inventive pump functions according to the following principle: the fluid, when induced to oscillate, performs transverse oscillations in the second section ( 3 ) with the variable delivery cross-section and can thereby expand or flow in said oscillating system, while in the first section ( 1 ) with the invariable delivery cross-section the fluid oscillates not at all or only to a much lesser extent depending on the compressibility of the medium. The waves caused by the oscillation produced in the fluid therefore substantially expand in the direction of the second section ( 3 ) with the variable delivery cross-section so that the fluid inevitably flows from the first section ( 1 ) to the second section ( 3 ).
1. A pump comprising:
a pipe through which material is conveyed between an inlet and an outlet, said pipe having an upstream segment with a fixed delivery cross section, and a downstream segment with a variable delivery cross section;
a rigid partition that divides said upstream segment lengthwise;
an elastic partition that divides said downstream segment lengthwise and that has a downstream distal end that is attached to said outlet; and
means for producing transverse oscillations in the material, said means for producing being located in an area in which said upstream segment is connected to said downstream segment,
wherein lateral movement of said elastic partition is caused by oscillations of the material, and
wherein said upstream segment has a length so that oscillations in the material in said downstream segment are reflected on the material in said upstream segment.
2. The pump of claim 1 , wherein said means for producing transverse oscillations comprises a plate that is moved laterally in said pipe, said plate having an upstream edge flexibly attached to a downstream end of said rigid partition and having a downstream edge attached to an upstream distal end of said elastic partition.
3. The pump of claim 2 , wherein only one said plate is between said rigid partition and said outlet.
4. The pump of claim 1 , wherein said upstream segment is at least as long as said downstream segment.