GB944651A - Improvements in or relating to water heaters - Google Patents

Abstract

944,651. Electric water heaters. T. B. NELSON, E. NELSON, H. NELSON, and F. NELSON. Jan. 20, 1960 [Jan. 24, 1959], No. 2661/59. Heading H5H. [Also in Division F4] A water heating system includes a closed boiling water tank fed by a supply conduit having a non-return or back-pressure valve; heating means having both a thermostat adjusted to a predetermined temperature below boiling point and a switch for optionally rendering the heating means operative to boil the water; a vapour withdrawal conduit connected above the normal water level and having a control valve; and a boiling water withdrawal conduit connected below the normal water level; whereby, if the water is boiled and the control valve closed the operated steam pressure forces water out of the boiling water withdrawal conduit. Boiling water tank 10 is fed from cold water supply 13 via warm water tank 11 and non-return valve 18, and includes a thermostatically controlled heating element 20, and two further heating elements 22 and 23 which are energizable by manual operation of a switch to boil the water. Hot water can be withdrawn from tank 10 via conduit 25, and boiling water via conduit 40 by closing valve 31 in the vapour withdrawal conduit 30 which leads to a heat exchanger consisting of coaxial tubes 32, 33 mounted in, and heating, the warm water tank 11, tube 33 being in communication with the atmosphere by way of the loose fitting cap 35. Steam may be withdrawn via conduit 45 by opening valves 31 and 44. The boiling water withdrawal conduit 40 projects into a longer bore tube 42, and extends therein below the level of an air inlet 43, to prevent syphoning. The operating lever 51 of valve 31 may be arranged automatically to switch off the additional heaters 22 and 23 when it is operated to close the valve in order to withdraw boiling water. A modification (Fig. 3, not shown) dispenses with the hot water withdrawal conduit 25, but has a mixing vessel connected in conduit 17 between the warm water tank and the valve 18, which in this case is of back-pressure type, whereby water drawn off through a hot water withdrawal conduit from the mixer consists of a mixture of water from tanks 10 and 11. Specifications 944,652 and 944,653 are referred to.