GB1111951A - Mine gas determination apparatus including radio transmitting and receiving equipment for sending monitoring signals - Google Patents

Abstract

1,111,951. Radio and inductive signalling. R. HœBNER. 10 Jan., 1966 [21 Jan., 1965], No. 1052/66. Headings H4L and H4U. [Also in Division G1] Mine gas determination apparatus comprising a mobile instrument with a coupled radio transmitter and in which reception of a signal by a receiving unit causes an associated transmitter to send a " message received" signal on another frequency to the transmitting unit concerned, where it operates an indicator, is described with reference to the forwarding to a control centre of the readings taken along mine workings by the instrument. A deputy carries an instrument 2, Fig. 1, a transmitting unit 1, and a receiver 3. The operation of a key starts the determination of gas content and switches on the radio equipment. The results may be transmitted as frequency variations of the unit 1. A visual or audible indicator is operable by the receiver 3. Reception of signals from the deputy's portable unit is effected by stationary receiving units 5 which are spaced along the mine workings so as to give continuous coverage, and which are linked together and to the control centre by leads 8, which may also serve as aerials. Each receiving unit 5 has a confirmation transmitter 6 adapted to send a " message received " signal to the deputy. In another embodiment, each stationary unit acts as a radio relay station and comprises a relay transmitter (9), Fig. 2 (not shown) in addition to the receiving unit (5) and the confirmation transmitter (6), no leads between stations then being required.