Patent GB-694350-A (GB)
Title: Device for determining and regulating the temperature and depth of ash in gas producers and like furnaces
IPC: C10J3/42
Filed: 1951-11-09
Abstract: 694,350. Automatic temperature control systems. GAZ DE FRANCE (G.D.F.) SERVICE NATIONAL. Nov. 9, 1951 [Nov. 10, 1950; July 4, 1951], No. 26334/51. Class 38 (iv). [Also in Group XII] The operating condition of a gas-producer or like furnace fed with solid fuel is regulated by one or more thermocouples, immersed in the ash or residue in the lower part of the container, and connected with relay means adapted to start, stop or vary the speed of a motor driving a revolving grate, and to operate indicator or alarm devices according as the temperature reaches upper or lower limits, the thermocouple being enclosed in a case and situated in the axis of the revolvable grate. As shown in Fig. 2, the gasproducer 22 is fed with solid fuel from above, and with air and steam from below through a revolvable grate 21 driven by a motor 24. At the upper part of the stepped grate two thermocouples 26, 27 are supported within a protective cover 25. The thermocouples are connected to two relay devices 28, 29 arranged to control indicator or alarm devices 33, 34, and to regulate the motor 24. The relay circuits, Fig. 3, comprise supply lines 40, 41 across which is connected the relay 28 comprising a temperature-indicating pointer 35 associated with the thermocouple 26 and moving between limit contacts 36, 37. When either of these contacts is reached, one or other of two normally-closed switches 38, 39 is opened and a normallyenergized relay 47 is disconnected from the mains, thus opening the circuit of a lamp 60 at the contact 47a, and closing the circuit of a lamp 67 and sound alarm 34 at the contact 47b. The second thermocouple 27 controls a pointer moving between contacts of the relay 29 set to narrower limits than those of the relay 28. If temperature is too low, a relay is energized to close the normally-open contact 81, thus connecting the relay 63 across the supply through a normally-closed contact 78. The relay 63 closes a holding-contact 63b shorting the contact 81, a contact 63a to light an indicator lamp 64, and a contact 63c to start the motor 24. The consequent removal of ash from the grate raises the temperature of the thermocouples and causes the pointer of the relay 29 to move towards the upper limiting contact. This movement is accelerated owing to the contact 63a switching into circuit a heater 85 associated with a further thermocouple 27a. When the limit contact is reached, contact 78 is opened to de-energize the relay 63 and stop the motor 24. A separate fuse 68 is provided in the circuit supplying the grate-control relay 63, the fuse 43 protecting the remaining circuits. An excess current relay switch 49 protects both relays 47, 63. A manual switch 70 normally on contact 75, gives manual control of the grate-control relay 63 and of the grate motor 24, when thrown to the contact 72. The relays 28, 29 controlled by the thermocouples are of the type in which impulses are given automatically to their movable members. Specifications 670,464, [Group XII], and 694,336 are referred to.