| 摘要 |
594,953. Filters. PETERSON, C. L., and PETERSON, C. J. Aug. 8, 1944, No. 15052. [Class 46] Liquid to be filtered is supplied to a chamber formed by two rotating filtering drums D, D<SP>1</SP>, Figs. 1 and 2, and side plates 53, the drums, which are in contact with each other, being provided with radial sections formed by partitions 20 extending from the vicinity of the centre of each drum to the circumference, and a pressure medium being applied to the sections near the line of tangency to expand the filtering medium thereat and prevent or reduce leakage of the liquid B. The sections of each drum are connected by ports 21 with a valve 22 having connections 23, 24, 25 for low vacuum, high vacuum and compressed air or steam, respectively. With the drums in the position shown, section 12 of drum D is subjected to pressure, section 14 to neither pressure or vacuum, and sections 16, 18 to low vacuum. The sections of drum D<SP>1</SP> are similarly affected as they come into similar positions. The filter cake formed on the drums is washed by means of spray pipes 43 near to which the sections are subjected to high vacuum. Spray pipes 63 are also provided. The filter cake is removed by scrapers S. A drip pan 56 is provided to collect any liquid that may leak from the space above the drums. The liquid to be filtered is uniformly distributed along the chamber above the drums by means of a spreading plate, a well and an overflow trough. The filtering medium is secured to the drums by means which include straps 39 extending around the drums, the straps of one drum being staggered with respect to the straps of the other drum. In a. modification shown in Fig. 6 the drum D only is a filter drum, the drum R being imperforate. This drum acts as an overflow to provide a constant depth of liquid above the drums. |
