SU627341A1 - Level indicator - Google Patents

Description

one

The invention relates to instruments and means of automation, namely IJ to the level detector of any electrically conductive medium, such as water in a steam boiler drum.

A known level indicator of an electrically conductive medium, which contains an electrode sensor, an amplifier, and an output electromagnetic relay.

The reliability of a known level alarm device is that it does not. signals the occurrence of a short ekgakayii on the body of the probe, and a short test leads to a failure of the device.

The closest in technical essence to the proposed level detector is a level detector comprising an electrode sensor, an amplifier, a input relay and a power source.

However, measurement reliability is insufficient.

The aim of the invention is to improve the measurement reliability.

The goal is achieved by the fact that the level indicator is additionally equipped with a short circuit signal generator, made in the form of two series-connected inverters connected between the amplifier and power supply, and a resistor, one end of which is connected; to the input of the first inverter and the other the input of the second inverter.

The drawing schematically shows a level indicator.

l

The level indicator of the electrically conductive medium in the vessel 1 includes an electrode sensor 2, a short circuit signal conditioner consisting of a resistor 3, an inverter 4, an inverter 5, an amplifier b, an output electromagnetic relay 7, a power supply 8 with a storage filter capacitor 9.

Claims (2)

The operation of the proposed detector is that with an acceptable level of the electrically conductive medium, i.e. when the electrode sensor is in contact with an electrically conductive medium, the metal vessel body is electrically conductive through the circuit; the electric sensor is an electric current that charges the accumulating filtering capacitor of the power source. In this case, a single negative voltage signal appears at the input of inverter 4. After the inverters 4 and 5 double invert, a single negative voltage signal is applied to the input of the amplifier. The amplifier goes into saturation state, turns on the output electromagnetic relay, opens its normally closed contact in the alarm circuit. When the electrode sensor comes in contact with an electrically conductive medium, a resistor is flowing through one resistor to one of the inputs OR of the inverter 5 (insufficient to put the inverter 5 into saturation mode5, which does not affect the steady state of the inverter 5. When the level of the conductive medium drops below the installed electrode sensor the metal case of the vessel is torn - electrically conductive - medium, - electrode sensor, no electric current flows, a single negative signal is removed from the input of the inverter 4 voltage. After double inversion, a zero signal is supplied to the amplifier input (i.e., a single negative voltage signal is removed), the booster amplifier is in the cut-off state. The output electromagnetic relay is turned off, including the alarm signaling by its trip contacts. to the body of the electrode sensor or its line of communication, both when the electrode sensor is in contact with an electrically conductive medium, and in the case when the electrode electrode is in contact with the Hpfl electrostatic (no medium (medium below The permissible level monitored by the electrode sensor), at the input of inverter 4, there is a single signal of negative voltage. 6 After inverting by inverter 4, a zero signal is applied to one of the outputs of inverter 5. In this case, the output electromagnetic relay should be turned on through the amplifier. However, due to a short circuit, a significant electric current flows through the resistor and a different negative voltage signal is supplied to the other input: inverter 5, which sets inverter 5 to saturation (the output of inverter 5 is zero), while the amplifier goes to cut-off, disconnecting the output electromagnetic relay, which by its own contact, turns on the alarm. Thus, in the proposed signaling device, a short circuit to the housing is signaled in the circuit of the electrode sensor of its communication line. After switching on the time delay element between inverters 4 and 5 (in order to prevent false triggering of the Level indicator), the proposed analyzer can be used to signal the water level, for example, in a ship's steam boiler. Invention The level indicator containing an electrode sensor, amplifier, output relay and a power source, about tl and cussed by the fact that, in order to increase the reliability of the measurement, it is additionally equipped with a short circuit shaper, made in the form of two Inverters connected between the amplifier and the power supply, and a resistor, one end of which is connected to the input of the first inverter and the other to the single input of the second inverter. Sources of information taken into account in the examination 1. UK Patent 1272398, cl. Q- IH, 1972. 2. Authors certificate of the USSR W 169817, cl. Q 01 R 23/24, 1964.