Patent GB-749574-A (GB)
Title: Improvements in or relating to heating and hot water supply systems
IPC: F24D1/00
Filed: 1952-02-05
Abstract: 749,574. Heating buildings; hot water supply systems; feedwater heating systems; heating air. AKTIEBOLAGET SVENSKA MASKINVERKEN. Feb. 5, 1952 [Feb. 6, 1951], No. 3051/52. Classes 64(1), 64(2) and 64(3). In a heating or hot water supply system, a fluid flowing in a closed primary circuit is continuously heated in that circuit and gives up heat in two heat exchangers 10, 10a to a fluid flowing in a secondary system. An automatically regulated part of the fluid heated in one heat-exchanger 10a is passed into the other  heat-exchanger 10, the regulation being dependent on the temperature of the fluid leaving the second heat exchanger 10. In each of the forms shown, the primary system comprises two heat exchangers 1, 2 forming part of a boiler, a drum 5, a pump 8, and two heatexchangers 10, 10a, the heat exchangers 1, 10 being in parallel with the heat-exchangers 2, 10a. In the secondary system, a pump 12 circulates water first through the heat-exchanger 10a and then through the heat-exchanger 10 and its by-pass 17, the flow through which is regulated by a valve 19 actuated by a temperature-responsive element 20 in the outlet pipe 16a. A by-pass 32, controlled by a valve 33 also actuated by the element 20, may be provided for the heat-exchanger 10 in the primary system. The flow of water through the heatexchanger 10a in the primary system is controlled by a valve 28 actuated by a temperatureresponsive element 29. Other systems combine two boilers and their associated primary and secondary circulating systems. The secondary systems have a common inlet and a common outlet. The primary systems may be quite separate from one another, or may have a common steam and water drum. In the latter case, valves actuated by elements responsive to temperatures in the drum and in the return pipes to it, control the water flow from the pump to the secondary systems. Heating air. The water flowing in the primary system may also be used to heat air in a heatexchanger 37, Fig. 5, connected either between the junction 21 and the heat-exchanger 10a or, as shown, connected in parallel with the heat-exchanger 10a. The flow of water through the heat-exchanger 37 is regulated by a valve 38 actuated by a temperature-responsive element 40 in the air passage. In a modification, the heat-exchanger 37 is connected to a third boiler heat-exchanger, which is connected to the inlet of the boiler heat-exchanger 2, and in another modification the heat-exchanger 37 receives its heating water from a point adjacent to the inlet of the boiler heat-exchanger 1. Heating feedwater. The water flowing in the primary system may also pass through a coil 48, Fig. 8, to heat make-up feedwater for the boiler. The feedwater is evaporated in the container 51, and condenses in the condenser 56, in which it heats the water in the secondary system, before flowing to the reservoir 59. The outlet of the coil 48 may, as in Fig. 9 (not shown), be connected to a point between the heat-exchangers 10a and 2. A valve 65 actuated by the level of water in-the reservoir 59 controls the flow through the coil 48. The supply of feedwater to the container 51 is controlled by a valve 53 actuated by a float 54.