JP2534989Y2 - Liquid level sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a liquid level sensor that electrically detects a liquid level.

(Prior Art) As shown in FIG. 4, a conventional liquid level sensor includes a liquid level sensor provided inside a cylinder 1 made of a non-magnetic metal material such as copper or aluminum and arranged vertically in the liquid. Substrate 3 to which a plurality of reed switches 2 are connected corresponding to the surface level detection position
Are covered with a heat-shrinkable insulating tube 4 and are inserted and fitted. A plurality of annular floats 5 having magnetism for operating each reed switch 2 are fitted to the outside of the cylindrical body 1 so as to be vertically movable. And an E-ring 7 is provided in a fitting groove 6 provided on the outside of the cylindrical body 1 corresponding to the lower position of each reed switch 2.
The vertical movement range of the float 5 is regulated by the E-ring 7.

A lid 8 made of the same material as the cylinder 1 is liquid-tightly fixed to the lower end of the cylinder 1 by brazing or the like, and a rubber cap 9 is fitted to the upper end of the cylinder 1. Have been.

Then, each float 5 moves up and down according to the liquid level, and in a downward movement state where the float 5 is outside the reed switch 2, the reed switch 2 receiving the magnetic action of the float 5 is turned on. Float 5
In the ascending movement state in which the reed switch 2 is disengaged upward from the reed switch 2, the reed switch 2 which is no longer affected by the magnetic action of the float 5 is turned off, and the liquid level is electrically controlled based on the on / off operation of each reed switch 2. Is detected.

(Problem to be Solved by the Invention) In the conventional liquid level sensor as described above, since the cylindrical body 1 made of a metal material is used, the cylindrical body 1 is cut into a predetermined length, and the fitting groove 6 is formed. Many processing steps are required, such as cutting, brazing of the lid 8, cleaning and plating, and inspection of the brazing portion leakage. In addition, the insulating tube 4 covering the substrate 3 is thermally shrunk to insulate it from the cylinder 1. Or E in the fitting groove 6 of the cylinder 1
The assembly is troublesome, such as fitting the ring 7, and the number of assembly steps is large.
Further, there is a problem that the number of parts is large, such as the necessity of using the E-ring 7 and the lid 8, and the production cost is extremely high.

The present invention has been made in view of the above points, and by integrally molding a cylindrical body with a synthetic resin, it is possible to reduce the number of processing steps and the number of parts, improve assemblability, and reduce manufacturing costs. It is an object to provide a liquid level sensor.

(Means for Solving the Problems) The present invention relates to a synthetic resin cylinder arranged vertically and a reed switch arranged inside the cylinder corresponding to a liquid level detection position. An annular float that has a magnetic action to actuate a reed switch and is fitted to the outside of the cylinder so as to be vertically movable, and at a plurality of locations on the outer peripheral surface corresponding to the liquid level detection position of the cylinder, A plurality of projections each having a substantially triangular shape and having an upper surface substantially in a horizontal plane and a lower surface formed as an inclined surface that rises in the distal direction to allow forcible upward movement of the float and restrict a range of downward movement of the float. The stopper is integrally formed.

(Operation) In the present invention, the float fitted to the outside of the cylinder moves up and down according to the liquid level, and the reed switch operates according to the up and down movement of the float, thereby detecting the liquid level. Done.

When the float is fitted to the outside of the cylindrical body, a plurality of stoppers are integrally formed on the outside of the cylindrical body. Since the lower surface is formed as an inclined surface that rises in the direction of the tip, the float easily moves upward from below the cylindrical body, so that the float easily gets over the stopper and fits above the stopper. Are combined.

Further, since the upper surfaces of the plurality of stoppers are formed substantially in a horizontal plane, the range of downward movement of the fitted float is restricted.

(Embodiment) Hereinafter, the configuration of an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

In the figure, reference numeral 11 denotes a cylindrical body integrally formed of a synthetic resin, an end plate 12 for closing a lower end face, and a flange portion 1 on an outer periphery of an upper end.
3, outer stopper 14 corresponding to each liquid level detection position
Are integrally formed. The stopper 14 has a substantially triangular projection 15 projecting from four circumferential positions at each liquid level detection position. The upper surface has a substantially horizontal surface, and the lower surface has an inclined surface that is inclined upward in the distal direction. I have.

A board 16 is inserted and fitted into the inside of the cylindrical body 11 from above, and a plurality of reed switches 17 are connected and arranged on the board 16 corresponding to the respective liquid level detection positions. A predetermined lead wire 18 connected to and pulled out from the upper end of the wire 16 is connected by wiring.

A plurality of floats 19 are vertically movably fitted to the outside of the cylindrical body 11 corresponding to the respective liquid level detection positions.
The float 19 is made of a synthetic resin foam containing magnetic powder and integrally molded in an annular shape, and magnetized to actuate the reed switch 17 on the magnetic material. As shown in the figure, the float 19 is fitted from below the cylindrical body 11 and is pushed in while elastically deforming the stopper 14 upward, so that the stopper 14 returns to the original state after passing through the float 19, so that the float 14 moves downward. The stopper is prevented from falling off, and the vertical movement range is restricted between the upper and lower stoppers 14, and between the liquid stopper level detection positions between the uppermost stopper 14 and the cap body 20 described later.

Further, a rubber or metal cap body 20 is fitted and fixed in a liquid-tight manner on the outer periphery of the flange portion 13 at the upper end of the cylindrical body 11, and a rubber seal 21 from which a lead wire 18 is drawn out inside the cap body 20 is provided. An epoxy seal layer 22 filled with an epoxy resin is formed on the rubber seal 21 while being fitted, and is sealed in a liquid-tight manner. In addition, this cap body 20
Before fitting the float 19 to the outside of the cylinder 11,
Outside.

Then, the liquid level sensor configured as described above is mounted according to the liquid level detection height in the liquid layer containing the liquid.

Each float 19 according to the fluctuation of the liquid level in this liquid layer
Moves up and down, that is, if the liquid level rises, it rises in order from the lower float 19, and if the liquid level goes down, it descends in order from the upper float 19.

Then, in a state where the float 19 is lowered and is engaged with the stopper 14 and the lowering is restricted, the float 19 faces the outside of the reed switch 17 in the cylindrical body 11, and the magnetic action of the float 19 causes the reed switch to move. 17 turns on.

When the float 19 rises, the float 19 moves to the cylindrical body 11.
The reed switch that has deviated upward from the position facing the reed switch inside, and the magnetic action of this float 19 has stopped working
17 turns off. The upward movement of the uppermost float 19 is restricted by contacting the cap body 20, and the other upward movement of the float 19 is restricted by the upper stopper 14.
Is regulated in abutment.

Then, if the uppermost float 19 rises and the uppermost reed switch 17 is turned off, it can be detected that the liquid level is the highest, and only the uppermost float 19 lowers,
When the uppermost reed switch 17 is turned on, it can be detected that the liquid level is one step lower. Also, when the float 19 in the middle part is lowered and the reed switch 17 in the middle part is turned on, the liquid level is further increased. If the lowermost float 19 can be detected and the lowermost reed switch 17 is also turned on, it can be detected that the liquid level is the lowest, and therefore the liquid level can be detected in four steps. Can be detected separately.

As described above, by integrally molding the cylinder 11 having the stopper 14 with a synthetic resin, the number of processing steps and the number of parts can be reduced, and the float 19 is simply press-fitted to the outside of the cylinder 11. Easy to assemble, about 1/2 ~ 1
Cost can be reduced to / 3. Also, about 1 / compared to metal
The weight can be reduced to 5 to 1/10, and packaging and transportation costs can be reduced.
Furthermore, the insulating property can be ensured without covering the substrate 16 inserted and fitted inside the cylindrical body 11 with an insulating tube.

(Effects of the Invention) According to the present invention, since the stopper is integrally formed on the outer peripheral surface corresponding to the liquid level detection position of the synthetic resin cylindrical body, the number of processing steps and the number of parts can be reduced, and the cylindrical body can be reduced. When the float is fitted on the outside of the cylinder, a stopper is integrally formed on the outside of the cylinder, but the stopper is not formed on the entire circumference of the cylinder, but is substantially triangular at a plurality of locations on the outer peripheral surface of the cylinder. Since the upper surface of the stopper is formed in a substantially horizontal plane and the lower surface is formed as an inclined surface that rises in the distal direction, the float is forcibly moved upward from below the cylindrical body, so that the stopper is formed above the stopper. It can be easily fitted, the assemblability is improved, and the manufacturing cost can be reduced.

[Brief description of the drawings]

1 is a sectional view showing an embodiment of the liquid level sensor of the present invention, FIG. 2 is a bottom view thereof, FIG. 3 is a partial sectional view showing an assembled state, and FIG. 4 is a conventional liquid level sensor. It is sectional drawing of a level sensor. 11 ... Cylinder, 14 ... Stopper, 17 ... Reed switch,
19 ... Float.

Claims (1)

(57) [Scope of request for utility model registration] A synthetic resin cylinder disposed vertically, a reed switch disposed inside the cylinder corresponding to a liquid level detection position, and a magnetic action for operating the reed switch. An annular float fitted to the outside of the cylindrical body so as to be vertically movable, and having a substantially triangular projection shape at a plurality of locations on the outer peripheral surface corresponding to the liquid level detection position of the cylindrical body; The upper surface is substantially horizontal, and the lower surface is formed as an inclined surface that rises in the direction of the tip. A plurality of stoppers are formed integrally to allow forcible movement of the float upward and restrict the range of movement of the float downward. Liquid level sensor.