Patent GB-1225487-A (GB)
IPC: G21C15/253
Filed: 1967-05-23
Abstract: 1,225,487. Gas-cooled reactors. ENGLISH ELECTRIC CO. Ltd. 23 May, 1968 [23 May, 1967], No. 23844/67. Heading G6C. A concrete pressure vessel 10 enclosing the reactor core space 11 has a number of vertical cylindrical holes 13 in its side wall each containing a boiler 14 and gas circulator unit 15. Each circulator unit consists of a gas blower 16 connected by a drive shaft 17 to an electric motor 18 and is supported in a steel liner 20 by a removable ring 28 engaging a liner groove 34. The motor 18 has a casing 25 closed at its upper end by a plate assembly 24 connected to the blower casing 16A, the lower end of the casing being closed by a diaphragm 26 having a sealing flange 26A resting on the ring 28. To remove the unit 15 the reactor is partially depressurized and the space between the diaphragm 26 and a pressure plate 21 is reduced to atmospheric pressure. A ring 33 is disengaged from its groove 33 in the liner 20 and the plate 21 is removed into a service space 23; also, electric leads 30 and water-cooling pipes 29 for the motor 18 are disconnected. A flask (not shown) is brought into the space 23 and coupled to the bottom of the hole 13, the reactor gas pressure being resisted by the diaphragm 26. Equipment within the flask then removes the ring 28 and enables the unit 15 to slide under the control of jacks through the liner 20 into the flask. Finally, a temporary pressure plate is attached to the bottom of the hole 13 and the flask is removed. 1,225,522. Road traffic signalling apparatus. LABORATORY FOR ELECTRONICS Inc. 21 Feb., 1968 [21 Feb., 1967], No. 8416/68. Heading G4Q. Signals 24 controlling entry of traffic to a motor way 10 from a road 18 via a slip road 16, are energized when signals from a vehicle detector D1 indicate that there is a sufficient gap in the traffic, after a delay such that a vehicle passing the signal 24 will reach the merging area 20 at the same time as the gap occurs at that point. Detectors D1 and D2 may be sonic or inductive loop detectors and provide outputs indicative of vehicle presence and of vehicle speed. Absence of a signal from D1 starts a resistance-capacitance timing circuit (Fig. 3, not shown) in gap detector 48; the permissible gap reduces as the speed of vehicles on road 16 increases, and this speed is measured by detector D2 and speed computer 56, classified into ranges in unit 58, and used to alter the charging resistance in the gap detector 48. Alternatively, the speed of traffic on the motorway may be measured by detector D6 and used to vary the required gap length. Detector 48 provides an output on line 49 when there is a gap sufficient for one vehicle to emerge, and an output on line 51 when the gap is sufficient for more than one vehicle to emerge. The signals on lines 49 and 51 pass to the gap projector 50 which produces corresponding outputs on lines 52 and 54 after a delay corresponding to the time taken for the gap to move from detector D1 to the merging area 20. Line 54 is connected directly to the signal controller 44 and line 52 is connected to the controller through a gate 53 which is open if a vehicle is detected by detector D4 in front of the signal point 24. Gate 53 is inhibited if a vehicle has waited in the zone of detector D2 for longer than the period of timer 60. If the queue of vehicles extends back to detector D5 for longer than the period of timer 68, a call is made on the controller 44 provided AND gate 62 is not inhibited by the output of timer 60. A detector D3 provides a signal to the controller 44 on line 64 to indicate that a vehicle has passed so that the signal may revert to STOP if the gap is sufficient for only one vehicle to pass. The signals may be switched to GO by a signal on line 42 if the traffic on the motorway is sufficiently sparse and fast moving, as measured by volume detector 36 and level monitor 38 and by speed detector 30 and level monitor 34. Gap projector 50, Fig. 4. Cessation of a signal on line 47 from detector D1 (Fig. 1) provides a pulse which sets bi-stable 194 which feeds an input into shift register 200. This is driven by pulses from a multivibrator 208 operating at a frequency corresponding to the speed of traffic on the motorway which is classified into ten ranges to provide signals on one of the lines L1-L10. If the gap is insufficient, a fresh signal on line 47 resets the bistable 194 and the register 200. If the gap signal G1 on line 49 from the gap detector arrives before this, the contents of the register are transferred to register 202 which is also driven by the multivibrator 208. When the signal reaches the end of the register an output signal G1<SP>1</SP> is provided on line 52. If the gap detector provides a signal G2 on line 52, indicating a gap suitable for more than one vehicle, this is transmitted to the output line 54 when the signal G1<SP>1</SP> is generated. Since traffic at signal 24 (Fig. 1) must be released earlier if traffic on the motorway is moving faster, the output of the register 202 is taken from AND gates 206 which are opened by the speed signals L1-L10. Signal controller.-Fig. 5 shows a system employing traffic lights, but the system may alternatively employ a barrier. When there is an input on line 66 indicating that a single vehicle may pass, then provided a minimum red period timed in 270 has expired, AND gate 246 passes a signal through OR gate to set bistable 256, which operates a green signal light and to re-set bi-stable 254 and extinguish the red light. When the vehicle has passed the signal an input on line 64 (from detector D3, Fig. 1) is fed through gates 259 and 261 to end the green period and start a short amber period which is timed by unit 280, gate 284 being open due to the setting of bi-stable 290 by the original signal on line 66. If the vehicle does not pass the detector D3, the green period is ended by the timer 276. If there is an input on line 54 indicating that more than one vehicle may proceed, AND gate 261 is inhibited so that the green period lasts as long as the input on line 54 lasts; at the end of this period a long amber period is timed by timer 278, gate 282 being opened and gate 284 closed as a result of the input on line 54. A signal on line 42 (when traffic is light) similarly provides a GO signal as long as this input is present. A signal on line 70 (indicating a long queue) actuates a delay circuit 252 after which a green period is provided which is ended by the vehicle passed signal on line 64 or by the timer 276.