GB1269128A - Method of operating a heating system and apparatus therefor - Google Patents

Abstract

1,269,128. Central heating systems. ZENTRA ALBERT BURKLE K.G. 13 Nov., 1969 [13 Nov., 1968], No. 55750/69. Heading F4U. [Also in Division F2] In a heating system in which a heat transfer fluid (e.g. water) circulates from a heat source (e.g. a boiler) to heat transmitting means (e.g. radiators 4) and back to the heat source, arrangement is made to ensure a return flow of adequate temperature to the boiler in order to minimize corrosion therein by condensate from the boiler flue gases. The arrangement comprises mixing in a device 7 return water from the radiators 4 with primary flow water from the boiler such that the proportion of return flow water so mixed, at least over a range of temperature, decreases as its temperature falls, the arrangement also comprising a mixing manually or ambient-temperature actuated device 3 in which return flow from the radiators is mixed with boiler water flowing to the radiators. The two mixing devices may be combined in a single 4-way valve unit (Figs. 3 and 4 or Fig. 5), or as shown, the two devices may be separate. The system shown also includes a circulating pump 19. Fig. 2 shows one form of the device 7 having an inlet duct 11 for relatively cold water from the radiators and an inlet 13 for hot water from the boiler. The mixture which passes out through an outlet duct 14 is controlled by a bimetallic throttling element 17 which when the radiator return water is at its hottest assumes the position indicated at 23 and when at its coldest e.g. on starting up, assumes the position indicated at 21, so that the boiler return flow through the outlet 14 is always relatively hot. On the side facing the boiler primary flow, the bimetallic strip 17 may have a heat insulating 20 coating of plastics material so that it tends to assume the temperature of the radiator return flow. Fig. 3 shows a unit incorporating both the devices 3 and 7. A valve cock 41 (corresponding to device 3) operable either manually or automatically in accordance with ambient temperature, controls the proportions of boiler water (inlet 36) and radiator return water (inlet 38) passing through outlet 37 to the radiators; and the bimetallic throttle member 53 mounted either on a fixed bar 49 or on the partition wall 35 of the cock 41 (Fig. 5), and corresponding to the device 7, controls the proportions of boiler water (inlet 36) and radiator return water (inlet 38) being returned to the boiler through outlet 39.