Patent GB-615615-A (GB)
Title: Improvements in the automatic control of heat supply and distribution systems
IPC: F24D19/10
Filed: 1944-07-05
Abstract: 615,615. Automatic temperature-controlling systems. SCHRAMM, F. B. July 5, 1944, No. 12875. Convention date, May 13, 1943. [Class 38 (iv)] A heat supplying or distributing system, more particularly a radiator system for the separate rooms of a building has a temperatureresponsive regulating or controlling device associated with each radiator arranged to control the supply of the heating medium, e.g. steam, hot water, or hot air, in such manner that one regulator can take over control from another to control the heat supply when the temperature of the former exceeds a predetermined maximum or falls below a predetermined minimum value. The generation of the heat may be controlled by opening or closing a damper flue, or operating a blower to control the production of steam. As applied to a steamheated radiator system for different rooms or points 23-25 of a building, the invention may comprise three or more radiators such as 12- 14 connected by a steam supply pipe 15 to a boiler 11, the radiators being associated with thermostats 26-28 respectively. The generation of heat is controlled by a reversible twophase motor 36 which operates a draught damper 37 and check damper 38 of a conventional solid fuel fired boiler. The motor is of the induction type with a pair of oppositely wound main stator windings 41, 42 and a quadrature winding 43, and the control system involves three line conductors 31-33, whereby the winding 43 and one of the windings 41, 42 may be energized. A transformer 44 provides current. Overriding control may be exercised by the thermostats 27, 28 in rooms 24, 25, but extension or contraction of the system is provided for by switches 91, 89. Thermostat 27 controls the operation of a relay switch 34 with contact arms 62-64, of which 62 is normally open and controls the energization of a holding coil, 63 is normally closed and controls a normally closed shut-off valve 21 which is opened by the de-energization of a solenoid 75, while 64 operates alternatively between two contacts 67, 68 in the line circuit between the motor field windings and the corresponding switch arm 87 and contact 99 associated with the relay switch 35 of room 25. Relay switch 35, controlled by thermostat 28, is similar to switch 34 and has a contact arm 104 which controls the operation of the shut-off valve 22 of radiator 14. In the arrangement shown, the thermostat 26 in room 23 has " on " and " off " contacts connected to the field windings 41 and 42 of the motor, and a bimetallic strip 49 connected over a line 86 to one contact 95 of a two-way switch, so that when the switch arm 94 is in the position shown, the thermostat 26 can operate through the lines 85, 84 and switch arms 87 and 64, when the latter are in their lower position, to exercise a controlling effect directly on the motor. Alternatively, thermostat 26 can be cut out by closing switch arm 94 on to contact 96, whereby the system is controlled by thermostats 27, 28, in which case, with radiator 13 shut off by valve 21, and the switch arm 64 in its lower position due to an " off " movement by thermostat 27, the thermostat 28 shown in the " on " position will effect the energization of motor field 41 and the opening of the damper until room 25 attains the requisite temperature. Relay switch 35 is then short-circuited by movement of thermostat 28 to the " off position, whereupon valve 22 is closed by the energization of its solenoid and switch arm 87 drops to its lower position, thereby completing the circuit over lines 84, 85 and switch arm 94 on contact 96 to energize field winding 42 to close the damper. Instead of employing a damper regulator, an " on " and "off " heat control may be provided by a blower 107 driven by a motor 108 controlled by a relay 109; this system may be used as an alternative by providing a threeway change-over switch between its leads 113-115 and those to the damper system. The thermal-responsive switch 26 may be located either within the boiler 11 or within an aquastat 106 connected thereto. The system may be modified by employing thermal responsive switches having a single stationary contact. The Specification as open to inspection under Sect. 91 refers to the adaptation of the invention to the control of ultra-high-frequency or micro-wave energy through tubular waveguides provided with movable dampers or reflectors, and includes a reference to U.S.A. Specification 2,206,923. This subject-matter does not appear in the Specification as accepted.