Patent GB-1170772-A (GB)
Title: The Control of Hydraulically-Operated Equipment in Underground Mines
Inventor: MONKS HARRY
IPC: F16H43/00
Filed: 1966-02-18
Abstract: 1,170,772. Fluid logic and switching circuits. COAL INDUSTRY (PATENTS) Ltd. Feb. 10, 1967 [Feb.18, 1966], No.7278/66. Heading F1P. [Also in Division F2] A power pack P2 at the tail gate end of a mine face conveyer comprises a hydraulic drive motor (not shown) supplied by two pumps (not shown) in parallel each of which delivers through independently operated control valves V3, V4 each having a neutral by-pass position and thence through a directional control valve D2 whereby the hydraulic motor may be driven at half or full speed in either direction, and the power pack P1 at the main gate end includes a similar electric motor, two pumps, control valves V1, V2 and a directional control valve D1 together with an air compressor 10 driven by the electric motor and delivering into low and high-pressure lines 15, 16; the highpressure in line 16 and in several branches thereof serving to actuate the starter of the tail end electric motor and valves V1 to V4, D1 DL through relays operated by signals in the low-pressure line and branches thereof and which low-pressure signals are themselves controlled by fluid logical devices. By a fluid logic device is meant a fluidflow on/off valve having no mechanically moving parts, e.g., a turbulence amplifier, comprising a low-pressure air supply nozzle spaced by a laminar flow gap from a receiving aperture and provided with a low-pressure air input ductnormal to the direction of laminar flow which latter is destroyed when a signal is present in the input duct whereby the output from the receiving aperture ceases. In operation and assuming the main gate electric motor and compressor 10 and the two pumps to be running whilst valves V1, V2 are in neutral the tail gate electric motor is energized by pressing a button 23 thereby admitting lowpressure air through a branch 22 of line 15 to actuate a step-up relay 24 to admit high-pressure air from a branch 20 of line 16 to a line 25 thereby opening a step-up relay 27 to admit high-pressure air from a branch 29 of line 16 through the relay 27 to a piston 30 which energizes the starter of the tail gate motor. Operation of the starter actuates a solenoid valve 31 to admit air from a branch 29 into a line 32 leading to a visual indicator 33. The directional control valves Di, D2 are then positioned simultaneously into one or other of their two positions by manual operation of a lever to close one or other blocking means 47, 48 in branches 41, 43 of the low-pressure line 15 leading to the input sides of amplifiers 45, 46 thereby allowing low-pressure air from one or other branch 42, 44 to flow through its associated amplifier 45, 46 to actuate step-up relay 49 or 56 say 49 thereby admitting high-pressure air from branch 20 into a line 50 and branch 52 to actuate step-up relays 51, 53 which latter allow air from branches 54, 55 of line 16 to position valves D1, D2. To run the two hydraulic motors at half speed valves V2, V3 are opened simultaneously whilst V1, V4 remain closed. This is effected by pressing a button 60 in a branch 61 of line 15 which results in low-pressure air passing through an amplifier 62 to open a step-up relay 63 thereby allowing high-pressure air from a branch 64 to depress a piston 65 and so block two branches 67, 68 of line 15 connected to the inputs of amplifiers 75, 69. A signal in a branch 70 of line 15 is then transmitted through amplifier 69 to actuate a relay 71 and admit high-pressure air from a branch 72 of branch 20 to a whistle 73.which indicates that the conveyer is about to start. At this time a signal from the downstream side of amplifier 69 is admitted through a line 74 to a second input of amplifier 62 thus reclosing relay 63 and withdrawing piston 65 so that line 67 is opened to block an amplifier 75 in a branch 76 of line 15 and allow passage of air through an amplifier 77. A step-up relay 79 is thus opened and allows passage of high-pressure air from branch 20 through lines 80, 85 leading to relays 81, 88 which when actuated allow passage of highpressure air from branches 84, 89 of line 16 to open valves V2, V3. The actuators of valves V2, V3 are linked to normally closed valves 89, 90 which open with valves V2, V3 to allow highpressure air to pass through lines 91, 94 to visual indicators 92, 96 and to a step-down relay 97 which gives a low-pressure output whenever a highpressure input is absent. To run the hydraulic motors at full speed valves V1, V4 are opened simultaneously by pressing a button 110 in a branch 111 of line 15 to block the same and thus relieve one of the two inputs to amplifier 99; the other input which is connected by a line 98 to step-down relay 97 also being relieved. Amplifier 99 thus passes a signal from a branch 113 of line 15 to actuate a step-up relay 114 which connects a branch 115 of line 20. Pressure in branch 115 opens step-up relay 116 to connect a branch 119 of line 16 to the actuator of valve V1. V4 is similarly opened in response to air in a branch 89 and in a branch 160 which is opened by a relay 120 in response to a signal in branch 121 of branch line 115. To stop the conveyer a button 130 in a normally blocked branch 131 of line 15 is pressed to open said branch 131 and thereby block an amplifier 132 and thus interrupt the signal in a branch 133 of line 15 and open an amplifier 134 to pass a signal in a branch 135 to the second input of amplifier 77. The signal in branch 78 is thus blocked resulting in closure of the step-up relays 79, 81, 88 together with valves V2, V3. Closure of Vz, Vs results in closure of valves 89, 90 which interrupts lines 91, 94 and closes valve 93. The signal in line 95 thus ceases and relay 97 gives an output which interrupts the signal in branch 113 to close relay 114. This interrupts signals in branches 115, 121 thereby closing relays 116, 120 and allowing valves V1, and V4 to close. Alternatively the conveyer may be stopped by manually actuating any one of a plurality of valves 18 in a portion of line 15 extending along the length of the conveyer thereby venting the line to atmosphere.