RU28917U1 - Fluid level sensor - Google Patents

Abstract

A liquid level sensor containing a housing, inside the cylindrical part of which a reed switch is located coaxially with it, a float covering the cylindrical part of the housing with an annular magnet pressed along the inner surface, which can freely move along the generatrix of the cylindrical part of the housing, a contact connector and means for mounting the sensor to the tank with liquid located in the upper part of the housing, made detachable, characterized in that a permanent resistor is inserted inside the housing, the last connected consistently with the reed switch in the transmitter circuit.

Description

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LIQUID SENSOR

The inventive utility model is prepared for level indicators and can be used in numerous fields of technology, in particular in the automotive industry, to indicate the level of coolant, glass washer fluid, etc.

Known liquid level sensors, containing magnetically controlled contacts and a float with a magnet 1, 2. The design solution of the sensors is based on a reed switch, which is triggered by the movement of a permanent magnet fixed in a float located on the surface of the liquid, the level of which is to be indicated.

The closest in its features is a liquid level sensor (DLL) -1 3, containing a housing, inside the cylindrical part of which there is a reed switch, a float with a magnet hardened into it, coaxially covers the housing and can freely move along the generatrix of the cylindrical part of the housing along with a changing liquid level , which leads to the operation of the reed switch and the issuance of an indicator signal. The upper part of the sensor housing is detachable, contains a contact connector and means for attaching the sensor to the liquid tank.

A disadvantage of the known liquid level sensor is its low reliability, due to the fact that the sensor does not have a protective circuit, in the absence of which through closed contacts of the reed switch due to a very low transient coE5)

Karabanov C.M. Cedilin N.G. Laushkina M.B.

- no more than 0.1 Ohm) a considerable current may flow.

The absence of a protective circuit reduces the reliability of the reed sensors.

The inventive utility model solves the problem of creating a sensor that is reliable in operation.

This problem is solved by the fact that in series with the reed switch, a constant resistor is included in the sensor circuit, which is a limiting element that does not allow to exceed the limit value of the current flowing through the contact parts of the reed switch.

The resistor is located inside the level sensor housing and is connected to the sensor circuit. The necessity of introducing a resistor is caused by the possibility of accidentally getting the battery voltage directly onto the sensor contacts (for example, when u) both of the elements of the signaling and koshrol unit). In this case, the battery voltage (13.7 V) is supplied directly through the sensor connecting wires directly to the contact details of the reed switch, which have a resistance of not more than 0.1 ohms in the contact zone. The current flowing in this case through this zone significantly exceeds the maximum permissible value (0.25 A):

Imax U / R 13.7 / 0.1 137 A.

A resistor connected in series with the reed switch is a limiting element, which allows you to exceed the limit value of the current flowing through the contact parts. For example: with a resistor value of Ohm, the maximum current through the contact zone will be equal to

U. and check / R 13.7 / (100HH), 1) 0.137 A.

The current value of this value is in the zone of the operating currents of the reed switch and is quite safe for it.

The inventive utility model solves the problem of creating a liquid level sensor, reliable in operation.

This problem is solved in that in a liquid level sensor containing a housing, inside the cylindrical part of which a reed switch is located coaxially with it, a float covering the cylindrical part of the housing with an annular magnet pressed on the inner surface, which can freely move along the generatric cylindrical part of the housing, contact a connector and means for attaching the sensor to the liquid reservoir located in the upper part of the housing made detachable, a constant resistor is inserted inside the housing connected in series with the reed switch in the sensor circuit.

The distinguishing feature of the claimed dgggsh is the reliability of operation, since the constant resistor is a limiting element that does not allow to exceed the limit value of the current flowing through the contact parts of the reed switch.

The essence of the claimed utility model is disclosed in the drawing: FIG. 1 - liquid level sensor, section, side view; top view - figure 2.

The liquid level sensor has a housing 1 on a cylindrical section 2 of which the float 3 is coaxially placed, which can freely move along the generatrix of the cylindrical part of the housing between the plate 4 and the restrictive protrusion 5. A permanent ring 6 is pressed along the inner perimeter of the float. A reed switch 8 is located parallel to the ring magnet inside the housing on the holder 7. The sensor is inserted into the fluid reservoir and fastened to it with the help of a shaped nut 9 with longitudinal ribs on the external cylindrical surface. The contact connector 10 is mounted directly on the housing 1 with three screws 11. The housing is sealed by a gasket 12. To seal the tank with liquid, use splicing 13. The electrical contact of the contacts of the reed switch 8 with the electrodes 14

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pin 10 is carried out through a limiting resistor 15 and wires 16 located inside the sensor housing.

The sensor is screwed into the reservoir with the liquid and operates as follows. With a large amount of liquid in the tank, the float is in its highest position, and the reed switch is open. When the liquid level decreases below the controlled level, the float 3 moves down along with magnet 6, the reed switch breaks and closes the electric circuit, thereby signaling a drop in the liquid level in the tank to a certain 5 degrees.

The liquid level at which the signal is issued depends on the geometric dimensions of the sensor, in particular on the distance from the lower edge of the gasket 13 to the upper edge of the plate 4, assuming that the relative position of the float, magnet and reed switch is selected so that the reed switch operates when float in 1faynom lower position. The indicated distance depends on the overall dimensions of the sensor, in particular, on the length of the sensor housing.

The sensor is easily manufactured in an industrial environment using well-known technological methods.

The body, contact connector, nut, holder are made of plastic, the float is made of porous ebonite or foamed epoxy foam with a pressed ring ferrite magnet. As a reed switch, a commercially available KEM-2 is used. As a resistor, a commercially available C2-23 is used.

Sources of information taken into account during the examination:

1. The author's certificate of the USSR No. 538236, publ. 12/05/76., Bull. No. 45.

2. The author's certificate of the USSR No. 1569568, publ. 06/07/90., Bull. No. 21.

3. Certificate for utility model No. 972, stated. 08/25/93., Publ. 10.16.95., Bull. No. 10.

Claims (1)

A liquid level sensor containing a housing, inside the cylindrical part of which a reed switch is located coaxially with it, a float covering the cylindrical part of the housing with an annular magnet pressed along the inner surface, which can freely move along the generatrix of the cylindrical part of the housing, a contact connector and means for mounting the sensor to the tank with liquid located in the upper part of the housing, made detachable, characterized in that a permanent resistor is inserted inside the housing, the last connected consistently with the reed switch in the transmitter circuit.