GB617402A - Improvements in mine roof testing - Google Patents
Improvements in mine roof testingInfo
- Publication number
- GB617402A GB617402A GB29159/46A GB2915946A GB617402A GB 617402 A GB617402 A GB 617402A GB 29159/46 A GB29159/46 A GB 29159/46A GB 2915946 A GB2915946 A GB 2915946A GB 617402 A GB617402 A GB 617402A
- Authority
- GB
- United Kingdom
- Prior art keywords
- amplifier
- rock
- roof
- mine
- pick
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011435 rock Substances 0.000 abstract 6
- 230000006835 compression Effects 0.000 abstract 4
- 238000007906 compression Methods 0.000 abstract 4
- 230000005540 biological transmission Effects 0.000 abstract 2
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 abstract 1
- 239000005751 Copper oxide Substances 0.000 abstract 1
- 230000003321 amplification Effects 0.000 abstract 1
- 229910000431 copper oxide Inorganic materials 0.000 abstract 1
- 230000008878 coupling Effects 0.000 abstract 1
- 238000010168 coupling process Methods 0.000 abstract 1
- 238000005859 coupling reaction Methods 0.000 abstract 1
- 239000013078 crystal Substances 0.000 abstract 1
- 229960004643 cupric oxide Drugs 0.000 abstract 1
- 238000001514 detection method Methods 0.000 abstract 1
- 238000003199 nucleic acid amplification method Methods 0.000 abstract 1
- 238000009527 percussion Methods 0.000 abstract 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
- G01M5/0066—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by exciting or detecting vibration or acceleration
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F17/18—Special adaptations of signalling or alarm devices
- E21F17/185—Rock-pressure control devices with or without alarm devices; Alarm devices in case of roof subsidence
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
- G01M5/0041—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
- G01M5/0083—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by measuring variation of impedance, e.g. resistance, capacitance, induction
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Geophysics And Detection Of Objects (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
617,402. Testing the safety of mine roofs. GENERAL REINSURANCE CORPORATION. Sept. 30, 1946, No. 29159. Convention date, Oct. 25, 1945. [Classes 40 (i) and 118 (ii)] [Also in Groups XIX and XXXIX] In mine roof testing apparatus for measuring compression waves transmitted through rock from test stations, there is a low-frequency amplifier, a compression wave detector, and an indicating-device, the amplifier including a compensator comprising pre-calibrated means for changing the gain of the amplifier in a given number of steps corresponding to the differences in attenuation of compression wave transmission through the rock at the same given number of respective test stations located at predetermined distances from the detector, whereby the indications of the apparatus will be substantially constant when indicating waves originating at any of said stations at substantially equal amplitude and transmitted through rock of substantially uniform strength. An electric pick-up 4 of the piezo-electric or crystal type is placed in the rock roof in a known safe position, and is connected by a long cable 6 to an amplifier box, including a meter, which is strapped to the operator. The operator uses a percussion hammer to strike.a blow on the roof in the vicinity of the pick-up, adjusts the meter reading to a maximum, and then proceeds to other positions and notes the meter readings after striking the roof with blows of the same intensity. The amplifier is battery-operated and comprises three valves of the hearing-aid type, the valves V1 and V2 being double tetrodes, resistance-capacity coupled to provide substantially linear amplification of five stages. The valve V3 is a pentode, the output of which is connected to a resistor R15 connected through a coupling condenser C8 to a D.C. instrument 22 in circuit with a full-wave copper-oxide rectifier. Means may be provided for checking the output by an oscilloscope or telephone receiver. Values of the resistances and condensers are given for a typical amplifier. To suit the characteristics of the rock in the mine and to compensate for test distances from the pick-up 4, a compensator 27 is included comprising a variable resistor R6, R7, R8 connected in series between the slider of potentiometer resistor R5 and the first control grid of valve V2. At each point of switch S1 the gain of the amplifier will be increased to compensate for the attenuation in compression wave transmission through the rock between detection point and test stations at specified distances therefrom.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US617402XA | 1945-10-25 | 1945-10-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB617402A true GB617402A (en) | 1949-02-04 |
Family
ID=22037818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB29159/46A Expired GB617402A (en) | 1945-10-25 | 1946-09-30 | Improvements in mine roof testing |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB617402A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2869362A (en) * | 1954-07-08 | 1959-01-20 | Dunlop Tire & Rubber Corp | Machines for testing pneumatic tires |
| CN105781546A (en) * | 2016-04-19 | 2016-07-20 | 太原理工大学 | Wireless passive coal-rock interface recognition device |
-
1946
- 1946-09-30 GB GB29159/46A patent/GB617402A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2869362A (en) * | 1954-07-08 | 1959-01-20 | Dunlop Tire & Rubber Corp | Machines for testing pneumatic tires |
| CN105781546A (en) * | 2016-04-19 | 2016-07-20 | 太原理工大学 | Wireless passive coal-rock interface recognition device |
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