Patent GB-703793-A (GB)
Title: Hydraulic damper control
IPC: F01P7/12
Filed: 1951-09-27
Abstract: 703,793. Fluid-pressure servomotor-control systems; valves. VAPOR HEATING CORPORATION. Sept. 27, 1951 [Oct. 5, 1950], No. 22610/50. Class 135 A hydraulic damper control system suitable for the cooling system of two Diesel-electric locomotive engines comprises a pair of main dampers 10, 11, and an auxiliary damper 12 for delivering attemperating medium, e.g., cooling air to selected locations and means including separate fluid-pressure motors 26-28 controlled by means including a pair of thermostats 13, 14, for adjusting the dampers, and two pairs of electrical relays, each associated with one thermostat, for controlling the main damper motors, and electrical circuit means connected in parallel through the pairs of relays so that the pairs are selectively effective to control the auxiliary damper motor, one pair being selected when its thermostat is first to control its main damper. If the first engine is running at normal temperature so that mercury in thermostat 13 is as shown, solenoid 62, connected to contacts 51, 52, is short circuited so that switch 79 is closed and energizes solenoid 82 to close a motor exhaust valve 32. Solenoid 56 connected to the contacts 52, 53, is energized so that switch 63 for the pump 16 and motor 17 is open and switch 67 is open so that solenoid 69 is de-energized to allow a motor inlet valve 22 to close. Thus, the fluid motor 26 holds the damper 10 in a set position. If the second engine runs hot, then both solenoids 108, 110 are short-circuited respectively at contacts 103, 104 and 102, 103, so that switches 112, 114, 119, close to respectively drive the pump-motor, energize solenoid 117 and open inlet valve 24, and energize solenoid 76 and open inlet valve 23, and switches 123, 128, close to respectively energize solenoid 126 to close motor exhaust valve 34, and energize solenoid 87 to close motor exhaust valve 33. Pump pressure then moves the pistons of fluid motors 27, 28 downwards against springs to open the dampers 11, 12. When the contacts 103, 104 open due to cooling action of the open dampers, solenoid 108 is energized to close switch 130 to heat a coil 133 which makes the mercury in thermostat 14 again bridge the contacts so that motors 27, 28 actuate the dampers step by step. Similarly when the temperature of the second engine falls and contacts 102, 103 open, solenoid 110 is energized to open switches 123, 128, which respectively de-energize solenoids 126 and 87 to open exhaust valves 34, 33 and allow the springs to move the pistons and close the dampers 11, 12. But when the energized solenoid 110 closes switch 137, the coil 133 heats up to twice the previous extent, the mercury bridges the contacts again and the dampers close step by step. Dampers 10, 12, fluid motors 26, 27, inlet valves 22, 23, exhaust valves 32, 33 and heater switches 89, 97 for the thermostat heater 94 are similarly controlled by thermostat 13 through the relays 46, 47. The auxiliary damper inlet and exhaust valve-operating solenoids 76, 87, are respectively connected in parallel with the switches 72, 119 and 84, 128 so that if the second engine is calling for cooling air, the thermostat 14 controls both its main damper 11 and the auxiliary damper, and if the first engine requires cooling, its thermostat 13 controls its main damper 10 and the auxiliary damper 12.