Tube pressure filters

In a tube pressure filter which comprises a pair of coaxial, generally tubular inner and outer assemblies arranged one within the other and adapted to be supported in a generally upright position, an impermeable elastic sleeve disposed within and secured to the outer tubular assembly, a filter element disposed around and supported by the inner tubular assembly, outlet means for the discharge from the interior of the inner tubular assembly of filtrate (i.e. liquid) which has passed through the filter element and through apertures in the inner tubular assembly, and means for displacing the tubular assemblies axially relative to one another between first and second positions, the arrangement being such that in the first position of said tubular assemblies they co-operate with each other to define a closed chamber of annular cross-section which is divided into coaxial and non-intercommunicating inner and outer compartmenets by said impermeable elastic sleeve, the inner compartment having an inlet for a feed material comprising a mixture of a liquid and a particulate solid to be separated and the outer compartment having an inlet for a hydraulic fluid under pressure, and in the second position of said tubular assemblies said chamber of annular cross-section is open to enable the particulate solid to be discharged from the inner compartment, the improvement which comprises providing the inlet of the inner compartment in an upper end section of the inner tubular assembly, said inlet including a feed distribution system which comprises a substantially annular aperture extending around the upper end section of the inner tubular assembly and debouching into the inner compartment of said tube pressure filter, said substantially annular aperture being (a) constructed and disposed so that, in use, feed material debouching therefrom has a downward component of velocity and (b) in communication with an antechamber formed in the upper end section of the inner tubular assembly, into which antechamber a mixture to be pressure filtered can be introduced under pressure through a feed conduit.