Patent GB-190212786-A (GB)
Title: Improvements in Indicating at a Distance Displacements of Solid and Fluid Bodies
Inventor: BECK FRANZ
Filed: 1902-06-04
Granted: 1903-05-28
Abstract: 12,786. Beck, F. June 4. Speed indicators; pressure gauges; liquid levels, indicating; indicating at a distance electrically and pneumatically; indicating relative motion; indicating observations by instruments.-Relates to a method of obtaining the quantitative indication, at a distance, of displacements of solid or fluid bodies. A point, the movements of which are controlled at a distance electrically or pneumatically, is sent along a path of known length into contact with another point travelling towards it in the same path. An electric signal announces the fact of their meeting, and, knowing the distance travelled by the first point, that travelled by the second point is deduced. Fig. 2 shows the arrangement applied to measure expansion by heat, and hence temperature. 6, 7 are pivoted insulated needles having platinum tips 9, 8, which make electrical contact on meeting. The movements of the needle 6 are controlled by a bent bimetallic strip 12, to which it is attached, and the movements of the needle 7 by an ordinary Bourdon pressure gauge 13. The gauge 13 is connected to a compressed-air reservoir 16, and to a second gauge 15 at the observation station at a distance. Cocks 18, 19 are used to adjust for greater loss of pressure between the reservoir 16 and gauge 13 than between the reservoir and gauge 15, because of the greater length of tube involved between the reservoir and gauge 13. A valve 20 is controlled by means of an electromagnet 11, included with a battery in the circuit finally closed by the needle 6 meeting the needle 7. As the temperature at the needles rises, the strip 12 expands, causing the needle 7 to move towards the needle 6, and simultaneously the pneumatic apparatus is set working, causing the needle 6 to advance through the medium of the gauge 13, till it meets the needle 7. Completion of the circuit through the electromagnet results, and the valve 20 is thereby actuated, shutting off the gauge 15 from the reservoir 16. The reading of the gauge 15 thus corresponds to the reading of the gauge 13, and by means of an empirical scale of temperature gauge 15 can be made to read temperature directly. Fig. 3 illustrates the method applied to a liquid thermometer. A double U-tube has the part 23 filled with an expansible liquid like alcohol, which is also a poor conductor of electricity. Mercury fills the rest of the tube on both sides, terminating at 24 in communication with compressed-air apparatus as described above. A cylinder 29 can be moved by a screw so as to slightly adjust the mercury levels at 27, 26. When the mercury in 26 is in contact with the wire 30 electrical communication with the electromagnet before described is made through the mercury and wire 31. Rise of temperature causes expansion of the alcohol and consequent depression of the level of mercury at 26. Compressed air from the reservoir before described connected at 14 forces up this same level 26 until it reaches terminal 30 when the circuit containing the electromagnet is completed, and the valve 20, Fig. 2, is thus closed. The amount of air supplied for this purpose furnishes a measure of the displacement, and the temperature may be read off upon the gauge 15, empirically graduated. A further modification is described adapted to measure temperature by means of a pneumatically-controlled elastic disc, which actuates levers connecting with the electrical arrangement through a bent metal bar expansible by heat. Another modification indicates at a distance the extent of opening of a door or valve by means of two needles which are the terminals of the usual electric circuit, one attached to the door, and the other to a pneumatically-controlled elastic disc. Analogous arrangements may be used to find the velocity of an air current, level of liquid in a reservoir, rotational speed through the medium of a centrifugal apparatus, pressure and depression, and the like.