GB1119487A - Water heater - Google Patents

Abstract

1,119,487. Water heaters. A. L. MILLER. 12 Sept., 1966, No. 40561/66. Heading F4A. A water heater comprises a number of horizontal parallel finned water tubes 23 arranged in a plurality of passes between front and rear manifolds 21, 22, and situated above fuel burners (14, Fig. 1) within a casing (12). Baffles 24 for the flue gases are situated between and above the water tubes. From inlet pipe 43 and inlet chamber 39, the water flows in a first pass of tubes 27 across the heater to reversing chamber 34, then in a second pass of tubes 28 back to the front of the heater to chamber 45. From the latter chamber, the water flows in a third tube pass 29 to chamber 35 and then through a fourth tube pass 30 to outlet chamber 46 and outlet pipe 49. Part of the water supply to the heater by-passes the first two water passes by flowing directly from inlet chamber 39 to chamber 45 through by-pass aperture 52 which is sized to provide a suitable by-pass flow. In a modification (Fig. 3) the flow through this aperture 52 is controlled by a thermostatic valve (62) sensitive to the water temperature leaving the second water tube pass. Additionally some water may completely by-pass all the water tubes by flowing from inlet chamber 39 to outlet chamber 46 through spring loaded valve controlled openings 53, thereby maintaining the flow through the water tubes 23 independent of variations in the water supply pressure. Alternatively, a thermostatic control valve dependent on the outlet water temperature may be used to control the flow through the openings 53. Due to the use of the by-pass aperture 52, the resultant slower flow rate through the tubes of the first two passes, reduces condensation on the outside of these tubes. In a modification (not shown) only the first tube pass is so by-passed.