SU800656A1 - Level sensor - Google Patents

Description

(54) LEVEL SENSOR

one

The invention relates to the automation of chemical technology and can be used to control and automatically stabilize the level in environments of different viscosity, as well as to control the viscosity of the measured media.

A level sensor for bulk materials of the PUS-1800 type is known, which contains an electric motor with an impeller on the shaft, which mechanically acts on the nozzle-damper system when braking the impeller by the measured medium l.

However, this sensor does not have high reliability in view of the complex mechanical part, and also cannot be used in environments of different viscosity.

Closest to the proposed device is a level gauge of bulk materials containing a single-phase synchronous motor with a braking impeller on the shaft, a phase-shifting capacitor connected in series with one of the motor windings, a transformer, two rectifying bridges and switching device 2.

However, the relay does not allow its application in environments of different viscosity, as well as for monitoring the viscosity of the measured media.

The purpose of the invention is to expand the field of application of a level sensor in environments of different viscosity.

This goal is achieved by the fact that the level switch sensor is supplied with an additional two RC chains, and the transformer is equipped with an additional secondary winding, with the additional secondary winding of the transformer connected in parallel with the windings of the electric motor, one of the rectifying bridges connected in series with the winding of the electric motor and the phase-shifted capacitor, both rectification bridges are connected

0 with their second diagonals with RC-chains, and the sliders of the variable resistors of the RC-chains are connected to a switching device.

The drawing shows the implementation scheme of the proposed device.

The primary winding of the transformer 1 is connected to the power supply through terminals 2. The first secondary winding of the transformer 1 is connected to

0 windings 3 and 4 electric motors.

on the shaft of which there is a braking impeller (not shown).

A phase-shifting capacitor 5 and a rectifying bridge 6 are connected in series with the winding 4 of the electric motor, and the rectifying bridge 7 is connected to the second secondary winding of the transformer 1. The second diagonal of the rectifying bridges 6 and 7 are connected to the RC chains 8-11, and the sensitive relay 12 and a voltmeter 13, calibrated in viscosity units, is connected to sliders of variable resistors 9 and 10 included in the RC chains. ,

The voltage from the terminals 14 through the normally open contact of the relay 12 is applied to the load from the terminals 15.

A variable resistor 16 is connected in series with the primary winding of the transformer 1.

The principle of operation of the described sensor-relay is based on a comparison of the voltage drop on the winding 4 of the electric motor and the voltage taken from the second secondary winding of the transformer 1. When the level of the bulk material below the sensor impeller and the rotor of the electric motor rotates, the constant voltage removed from the winding electric motor 4 using a rectifying bridge b and KS chains 8 and 9, is balanced by the voltage removed from the second secondary winding of the transformer 1 using a rectifying bridge 7 and RC chains 10 and 11. At the same time e 12 is de-energized, the load is disconnected.

When the level of bulk material reaches the sensor impeller, the rotor of the electric motor is inhibited when exposed to a viscous medium on the impeller rigidly connected to the rotor. In this case, the voltage drop on the winding 4 of the electric motor decreases, which leads to the imbalance of the voltages taken from the resistors 9 and 10. Relay 12 operates to its normally open contacts, turns on the load through terminals 15.

When using a sensor to monitor the fluid's viscosity, the viscous fluid level is stabilized so that the fully braking impeller is immersed in the fluid. At the same time, the voltmeter 13 rotates the motor and shows the viscosity of the measured medium, which is uniquely associated with the braking torque on the shaft electric motor and, therefore, with the voltage drop across the winding 4.

In order to facilitate the adjustment of the sensor-relay in environments of different viscosity, the supply voltage of transformer 1 is made adjustable, for which purpose a variable resistor 16 is connected in series with the transformer primary winding.

Claims (2)

1. Mironov. K.A. and Shipetin LI. Thermal measuring instruments. Reference materials, M., 1954, p. 426-428. 2. USSR author's certificate number 483581, cl. G 01 F 23/00, 1973 (prototype).