GB732977A - Improvements in and relating to heat exchangers - Google Patents

Abstract

732,977. Heating air for combustion; platetype heat-exchangers. PARSONS & CO., Ltd., C. A. Sept. 10, 1952 [June 19, 1952], No. 15431/52. Classes 64 (1) and 64 (3). In an air-gas recuperator incorporating a number of matrix elements 11 each consisting of a plurality of cells having flow passages of small cross-section, e.g. as described in Specification 718,991, means are provided to maintain clean the flow passages of the matrix, in particular those passages through which flows the heating gas, by causing said gas to pass through a filter 16 before entering the matrix, and by providing an intermittent blast of cleaning fluid through the gas passages of the matrix to blow off deposits of dust. The cleaning fluid, which may comprise air with or without the addition of a further cleaning fluid, is supplied by a double-acting pump 22 which forces the said fluid through a pipe 26 to passages 19 formed within the matrix element and thence outwardly through the matrix passages to carry away the dust &c. At the same time the pump withdraws, through pipe 24, dust, &c. deposits which have collected at the hot gas entrance 17 of the element, which entrance is closed by a valve 23 for the short period when the cleaning blast is operating. Some of the cleaning fluid carries away dust &c. deposits to the cooled gas exit ports 18 of the matrix element being cleaned. As shown, two matrix elements 11 are contained in a casing 13 the valve 23 being synchronized with the pump 22 such that one element receives the blast of cleaning fluid whilst the second element remains operative. The valve 23 then operates to cut off the heating gas stream from the latter element whilst at that same time allowing the first element to operate normally. Other pipes similar to pipes 24, 26 are connected to each element 11 and the arrangement is such that cleaning fluid is supplied only to that element having its hot gas inlet port 17 closed by the valve 23, the pump operating continuously. The individual cells constituting an element are each subdivided into a plurality of flow passages by two corrugated strips which are spaced apart in the direction of gas flow to form the passage 19 for the cleaning fluid. The corrugations 19d of the strip may be larger than those 19c of the other strip to induce the cleaning fluid to flow more easily towards the zone 17 and hence to the pipe 24.