JP3052442B2 - Liquid level detection switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detection switch used for detecting the liquid level of an oil tank for a bearing lubrication device of a rotating device.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of an essential part of an oil tank to which a conventional liquid level detection switch is attached, for example for a bearing lubrication device of a rotating device. Lubricating oil 12 in oil tank 11
And 13 indicates the liquid level. The liquid level detection switch 10 includes a float 6 and a cylindrical permanent magnet 1 whose inner hole is inserted into and fixed to a rod 3 standing upright on the float 6.
Is housed in an outer cylinder 7 having an upper part thinner and a thicker lower part corresponding to the diameters of the permanent magnet 1 and the float 6 and a flange 7A provided at the center thereof. A magnetic switch 5 operated by one magnetic field is provided. The liquid level detection switch 10 penetrates the upper surface of the oil tank 11 and is fixed by a flange 7A.

The float 6 floats on the lubricating oil 12, and its position indicates the level of the liquid level 13. FIG. 4 shows a case where the liquid level 13 is higher than a predetermined minimum liquid level 13 L. The permanent magnet 1 fixed to the rod 3 of the float 6 is at a position higher than the magnetic switch 5 and is separated from the magnetic switch 5. Therefore, the magnetic switch 5 is off. If the liquid level 13 of the lubricating oil 12 decreases from this state due to wear of the lubricating oil or the like, the float 6 and the permanent magnet 1 also lower. When the permanent magnet 6 drops and approaches the magnetic switch 5,
The magnetic switch 5 operates and is turned on by the magnetic field. By setting the mounting position of the magnetic switch 5 to, for example, a position that operates corresponding to the minimum liquid level 13L, it is possible to detect that the liquid level 13 has dropped to the minimum liquid level 13L.

[0004]

In the above-described liquid level detection switch, when the liquid level drops to, for example, the minimum liquid level, the magnetic switch is turned on, and it can be detected that the liquid level has reached the minimum liquid level. When the liquid level further drops, the permanent magnet drops with the liquid level, so that the magnetic switch is turned off by separating from the magnetic switch. On the contrary, even if the liquid level rises, the permanent magnet separates from the magnetic switch and the magnetic switch turns off.Therefore, from the operation of the magnetic switch, after the liquid level reaches the minimum liquid level, the liquid level further decreases or recovers There was a problem that it was not possible to determine whether it had risen.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid level detection switch capable of determining whether the liquid level has further decreased after the liquid level has reached the minimum liquid level or has recovered and increased.

[0006]

In order to achieve the above object, a liquid level detecting switch according to the present invention comprises a float floated on a liquid at a liquid level to be detected, and a rod arranged vertically on the float. An axially movable permanent magnet, a first stopper provided on the rod so that the permanent magnet does not fall below a predetermined position of the rod, and a magnetic field of the permanent magnet provided around the rod. An operating magnetic switch and a second stopper provided so that the permanent magnet does not fall below the position of the magnetic switch.

[0007]

The liquid level detection switch according to the present invention comprises a float floating on the liquid at the liquid level to be detected, a permanent magnet movable in the axial direction along a rod standing upright on the float, and the permanent magnet comprising: A first stopper provided on the rod so as not to be lowered below a predetermined position of the rod, a magnetic switch provided around the rod and operated by a magnetic field of the permanent magnet, and the permanent magnet is positioned below the position of the magnetic switch. The permanent magnet supported by the first stopper provided on the float rod is lowered with the liquid level when the liquid level is lowered because the second stopper is provided so as not to be lowered. When the liquid level drops to, for example, the minimum liquid level, the permanent magnet approaches the magnetic switch 4 and the magnetic switch is turned on to detect that the liquid level has dropped to the minimum liquid level. When the liquid level further decreases, the float decreases as the liquid level decreases. However, the permanent magnet is held at the position of the magnetic switch by, for example, a second stopper provided on the magnetic switch. As a result, it is detected that the magnetic switch is kept on and the liquid level is further lowered. When the liquid level recovers and rises, the float also rises according to the liquid level, and when it rises to the lowest liquid level, the permanent magnet previously supported by the second stopper is supported by the first stopper and rises according to the float. Thereby, the magnetic switch is turned off and it is detected that the liquid level has risen.

[0008]

FIG. 1 is a sectional view of an essential part of an oil tank for a bearing lubrication device of, for example, a rotating device to which a liquid level detection switch according to an embodiment of the present invention is attached. The difference between the liquid level detection switch 10 of the present invention shown in FIG. 1 and the conventional liquid level detection switch shown in FIG. 4 is that the permanent magnet 1 has an inner hole inserted into the rod 3 of the float 6 and moves along the rod 3. The permanent magnet 1 is movable in the axial direction.
The permanent magnet 1 is supported by a first stopper 2 attached to a rod 3 so as not to fall below the predetermined position of the magnetic switch 5 or the outer cylinder 7 so as not to fall below the position of the magnetic switch 5. The point is that the second stopper 4 is provided.

FIGS. 2 and 3 show the operation of the liquid level detection switch 10 of the present invention shown in FIG. 1, and FIG.
The permanent magnet 1 decreases according to the float 6 which decreases according to the liquid level 13 and approaches the magnetic switch 5. When the permanent magnet 1 approaches the magnetic switch 5, the magnetic field causes the magnetic switch 5 to operate and switch on. As a result, it is detected that the liquid level 13 has dropped to the minimum liquid level 13L. The operation so far is the same as the operation of the conventional liquid level detection switch shown in FIG. FIG. 3 shows a case where the liquid level further decreases. The float 6 decreases as the liquid level 13 decreases, but the permanent magnet 1 is held at the position of the magnetic switch 5 by the second stopper 4. Thereby, the magnetic switch 5
Is kept on, and it is detected that the liquid level 13 is further lowered.

When the liquid level 13 recovers and rises, the float 6
The permanent magnet 1 also rises according to the liquid level 13 and rises to the lowest liquid level 13L, and the permanent magnet 1 supported by the second stopper 4 until then is supported by the first stopper 2 and the float 6
Rise according to. As a result, the permanent magnet 1 is separated from the magnetic switch 5, the magnetic switch 5 is turned off, and the liquid level 13
Is detected to have risen. This state is similar to the state shown in FIG.

In the above description, the magnetic switch 5 is provided at a position where it operates in accordance with the minimum liquid level 13L.
However, it is a matter of course that an arbitrary liquid level can be detected by providing the position of the magnetic switch 5 at a position corresponding to an arbitrary liquid level.

[0012]

According to the liquid level detection switch of the present invention, for example, after the liquid level has reached the minimum liquid level, it is possible to determine whether the liquid level has further decreased or has recovered and increased. In a bearing lubrication device for a rotating device using a switch, an alarm is continuously generated when the liquid level of the oil tank falls below the minimum liquid level, thereby preventing damage to the bearing metal of the rotating device.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of an oil tank to which a liquid level detection switch according to an embodiment of the present invention is attached.

FIG. 2 is a sectional view of a main part of an oil tank for explaining the operation of the liquid level detection switch of the present invention shown in FIG.

FIG. 3 is a sectional view of a main part of an oil tank for further explaining the operation of the liquid level detection switch of the present invention shown in FIG.

FIG. 4 is a sectional view of an essential part of an oil tank to which a conventional liquid level detection switch is attached.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet 2 1st stopper 3 Rod 4 2nd stopper 5 Magnetic switch 6 Float 11 Oil tank 12 Lubricating oil (Liquid of liquid surface to be detected) 13 Liquid surface (Liquid surface to be detected) 13L Minimum liquid level

Claims (3)

(57) [Claims] A float floated on a liquid on a liquid surface to be detected;
A permanent magnet movably in the axial direction along a rod erected perpendicular to the float, a first stopper provided on the rod so that the permanent magnet does not fall below a predetermined position of the rod, A liquid level detection switch comprising: a magnetic switch provided around a rod and operated by a magnetic field of the permanent magnet; and a second stopper provided so that the permanent magnet does not fall below the position of the magnetic switch. . 2. The liquid level detection switch according to claim 1, wherein the magnetic switch is provided at a position corresponding to a predetermined minimum liquid level. 3. A liquid level detecting switch according to claim 1, wherein said liquid level detecting switch is used for detecting a liquid level of an oil tank for a bearing lubricating device of a rotating device.