| 摘要 |
1,210,025. Electric selective signalling. GENERAL DESCALING CO. Ltd. 22 May, 1969, No. 26266/69. Heading G4H. [Also in Division G1] Apparatus for plotting one parameter against another comprises a strip chart recorder 40 including a chart drive and a recording pen movable across the chart 18 in response to an applied signal and a counter 30 receiving first and second signals corresponding to increments in each parameter respectively, the counter counting the second signals to generate an analogue signal proportional to the magnitude of the count and being reset to zero by the first signals. The apparatus may be used in the pressure testing of pipes &c., a pump 2 being connected by a tube 4 to the pipe whilst a conventional pressure gauge 22 and a deadweight pressure gauge measure the changes in pressure in the pipe due to the pumping of water into the pipe. Each stroke of the pump increases the volume of the pipe by a fixed amount, the number of strokes being registered on a counter 8 connected to a transmitter 26 in the form of a pair of contacts which are closed at each stroke of the pump. Volume signals are thus fed to the counter 30 and to a storage register 32 in the form of a uniselector switch, each signal stepping the uniselector forward by one contact. The uniselector switch contacts are connected between a chain of resistors which form a digital/analogue converter 34 connected to a range selector switch 38 and a stabilized power supply 36. The output from the converter 34 is applied to the pen drive of the recorder. Pressure signals corresponding to predetermined fixed movements in the pressure are applied to a triggering unit 42 either manually by a push-button PB2 operated each time an additional weight is placed on the gauge 24 or by a detector 28 transmitting a signal in response to the weight increments. On receipt of a signal the triggering unit 42 resets the register 32, the counter 30 and hence the recorder pen to its zero position. The triggering unit also actuates a chart drive control 44 to step the chart by an amount determined by a selector 46. The pen thus plots a graph of the increase in volume of the pipe for each pressure increment. An independent reset 52 in the form of a pushbutton is provided for the counter 30 whilst the recorder has a pen overtravel alarm 48 and an alarm acknowledge switch 50.
|
