JPH0450514Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a liquid level detector that is attached to the side wall of a liquid tank to detect the liquid level in the liquid tank, and in particular, a liquid level detector that is attached to the side wall of a liquid tank and uses a magnet attached to a float. This invention relates to a liquid level detector in which a reed switch is opened and closed by movement.

[Conventional technology and problems]

Conventionally, as shown in FIG. 5, for example, such a liquid level detector is installed on the side wall A of a liquid tank that receives the liquid whose liquid level is to be detected, by means of a male threaded part or the like provided on the circumferential surface of the side wall A. A stopper 1 made of metal, synthetic resin, etc. is attached, a stem 2 extends horizontally inward from the inner end surface of the stopper 1, and a normally open lead built into the stem 2. A switch 3 and a horizontally oriented hollow cylindrical float 4 that is fitted to the stem 2 with some play.
and a ring 5 fixedly arranged at the tip of the stem 2 so that the float 4 does not fall off the stem 2. Furthermore, a magnet or a magnet and a ring 5 are arranged above or below the inner surface of the float 4. A weight (not shown) is buried to keep the floating attitude constant.

According to the liquid level detector having such a configuration, when the liquid level to be detected is lower than a predetermined level, the float 4 is descending due to gravity, and the magnet and reed switch 3 are far apart or close to each other. When the liquid level rises and becomes higher than a predetermined level, the float 4 rises according to the liquid level due to buoyancy, and the magnet turns the reed switch 3 on or off. By approaching or moving away from the reed switch 3, the reed switch 3 is turned off or on, thus detecting the liquid level.

However, in the liquid level detector configured as described above, the positions where the magnets, weights, etc. are buried inside the float are not necessarily precisely designed in order to easily manufacture the float molded product. In addition, in cases where the liquid level fluctuates or there is large friction between the end surface of the plug 1 and the end surface of the ring 5 that contact the float,
The float 4 is inclined with respect to the liquid level and cannot be raised or lowered horizontally. Furthermore, even if the magnet and weight are designed to be located at the center of the float 4, positional errors during mass production or fluctuations in the liquid level during operation may cause the float 4 to move up and down horizontally with respect to the liquid level. Not easy to operate.

In this way, when the float 4 moves up and down on the liquid level, that is, while being inclined with respect to the stem 2, the edges of both end surfaces of the float 4 simultaneously contact both end surfaces of the stopper 1 and the ring 5, thereby causing , because it is held between the end faces of the plug 1 and the ring 5, and may get caught on both end faces, causing non-operation or malfunction of the liquid level detector.

Furthermore, even if the float 4 moves horizontally up and down, the float 4 may
Surface contact with the end face of the sensor may cause detection errors or operation delays due to adsorption.

On the other hand, by widening the distance between the end faces of the plug 1 and the ring 5, the pinching and catching of the float 4 can be avoided, but in this case, the play in the axial direction of the float 4 increases, so that the float 4 The center of the magnet embedded in the inner surface of the stem 2 may deviate significantly from the center of the reed switch in the stem 2, resulting in a decrease in the detection accuracy of the liquid level detector.

[Purpose of invention]

In view of the above points, the present invention has been developed so that even when a float whose center of gravity is biased and is tilted or a float that is moving horizontally moves up and down in an inclined state due to shaking, etc., the end surfaces of the float are opposed to each other so as to sandwich the end surfaces. An object of the present invention is to provide a liquid level detector that operates normally without being caught by the end faces of a stopper and a ring.

[Means and actions for solving the problems]

According to the present invention, the stem extends horizontally inward from the inner end surface of the stopper to be attached to the side wall of the liquid tank and has a built-in reed switch; It includes a horizontal hollow cylindrical float formed to have a lighter specific gravity and fitted with play to the stem, and a magnet buried above or below the inner surface of the float. This is achieved by providing at least one protrusion protruding outward in the axial direction on the end face of the float, at least on the side where the center of gravity is eccentric, in the horizontal liquid level detector.

According to this invention, a protrusion protruding in the axial direction is provided on the end face of the float, at least on the side where the center of gravity is eccentric, so that even when the float is lowered, the tip of the protrusion is attached to the stopper or the end surface of the float. By contacting the end surface of the locking member that restricts the float from falling off in the axial direction, the end surface of the float does not directly contact the end surface of the plug or the locking member, and the contact area with these end surfaces is significant. As it decreases,
The float is not attracted to the end face of the stopper or the locking member due to wetting, and the amount of movement of the float in the axial direction is reduced, thereby improving the vertical movement characteristics of the float.

Moreover, even when the float moves up and down at an angle, the float does not contact both end surfaces of the stopper and the locking member at the same time before the lower edge of the inner surface of the float contacts the stem.

Therefore, when the liquid level becomes higher than the predetermined level again, the float can float up in conjunction with the rise in the liquid level, so the float can become caught on both end surfaces of the stopper and the locking member, and as a result, It will not be pinched, and thus the liquid level detector will not be inoperable, malfunction, delay in operation, or other inconveniences.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows an embodiment of a normally open type liquid level detector according to the present invention. A plug body 1 made of, for example, metal, synthetic resin, etc., attached by a male thread provided on the circumferential surface.
1, a stem 12 extending horizontally inward from the inner end surface of the stopper 11, and a normally open reed switch 13 built into the stem 12.
, a horizontally oriented hollow cylindrical float 14 that is fitted with some play into the stem 12, and a float 14 that is fixedly arranged at the tip of the stem 12 so that the float 14 does not fall off the stem 12. It is composed of a ring 15. In addition, the above float 1
4 is made of a material such as a buoyant resin foam so that the specific gravity is lighter than that of the liquid whose liquid level is to be detected.

The above configuration is similar to that of a conventional horizontal liquid level detector.

According to the present invention, the float 14 further includes at least one (in this embodiment, a third) which protrudes in the axial direction on the end surface (both left and right end surfaces in the illustrated case) on the side where the center of gravity is eccentric. As shown in Figure 3, there are two protrusions 1 on each end surface.
4a and 14b are formed, and a magnet (not shown) and a weight for keeping the floating attitude of the float constant are buried below the inner surface. The protrusions 14a and 14b protrude horizontally with the liquid level, that is, with the stem 12, near the center in the vertical direction on both left and right sides or one side of the float end surface.

The embodiment of the liquid level detector according to the present invention is constructed as described above, and when the liquid level to be detected is lower than a predetermined level, the float 14 is lowered by gravity, and the magnet and reed switch 13 are connected to each other. The reed switch 13 is off due to the large distance between the two, but when the liquid level rises and becomes higher than a predetermined level, the float 14 rises according to the liquid level due to buoyancy, and the magnet approaches reed switch 13, reed switch 1
3 is turned on and liquid level detection is thus performed.

Here, if the liquid level is lower than the predetermined level,
The protrusion 14 formed on the end surface of the float 14
Since a or 14b comes into contact with the end surface of the plug 11 or ring 15, the end surface of the float 14 does not come into close contact with the end surface of the plug 11 or ring 15. If the liquid level fluctuates above a predetermined level from this state, if the float 14 rises horizontally,
The float 14 is in contact with the end surface of the stopper 11 or the ring 15 only through its protrusion 14a or 14b with a small contact area, and the end surface of the float 14 is caused by the surface tension of the liquid to cause the stopper 1 to
Since the float 14 is not attracted to the end face of the ring 1 or the end face of the ring 15, the float 14 rises as the liquid level rises without being tilted. At this time, since the amount of movement of the float 14 in the axial direction is reduced by the protrusions 14a and 14b, the protrusion 14a
Alternatively, by the contact of the float 14b with the end faces of the stopper 11 or the ring 15, the float 14 is guided along these end faces, improving the operating characteristics in the vertical direction.

On the other hand, as shown in FIG. 3, when the center of gravity of the float 14 is eccentric toward the plug 11 side, as the liquid level rises, first the upper edge 14c or the protrusion of the inner surface of the float 14 on the plug 11 side The ring 15 side (left side in the figure) of the float 14 rises with 14b as a fulcrum, and as a result of this rise, the ring 14 of the float 14 is only lifted when the inner lower edge 14d of the float 14 on the ring 15 side comes into contact with the lower surface of the stem 12. The lower edge 14e of the end face on the 15 side comes into contact with the ring 15,
Subsequently, the plug 11 side of the float 14 rises using the inner lower edge 14d or the protrusion 14a on the ring 15 side as a fulcrum. Therefore, after the raising operation on one end side of the float is completed, the other end side starts the raising operation, so that during the raising, the float 1
4 is not held between the stopper 11 and the ring 15 at the same time in an inclined state, and the float 14 rises smoothly. Furthermore, when the float 14 descends, smooth descent is achieved in the same manner.

In this way, the liquid level detector 10 can operate accurately without malfunctioning or malfunctioning.

Further, if both end surfaces of the float 14 are chamfered, the vertical movement of the float 14 can be performed even more smoothly.

In the above embodiment, the protrusions 14a and 14b provided on both end faces of the float 14 are formed in a shape that protrudes in the axial direction from the end face of the float 14, but the shape is not limited to this. As shown in FIG. 4, the protrusions 1 are formed so that the entire end surface of the float 14 is inclined in the vertical direction so that the entire end surface protrudes most near the approximately central portion in the vertical direction.
Similar effects can be obtained even with 4a' and 14b'.

[Effect of idea]

As described above, according to the present invention, there is provided a stem that extends horizontally inward from the inner end surface of the stopper to be attached to the side wall of the liquid tank and has a built-in reed switch, and a stem that is to be used to detect the liquid level. It includes a horizontal hollow cylindrical float formed to have a specific gravity lower than that of the liquid and fitted with play to the stem, and a magnet embedded above or below the inner surface of the float. In the horizontal liquid level detector, at least one protrusion protruding outward in the axial direction is formed on the end face of the float at least on the side where the center of gravity is eccentric.
Even when the float is lowered, the tip of the protrusion comes into contact with the stopper or the end face of the locking member that restricts the float from falling off in the axial direction, so that the end face of the float does not directly contact the stopper or the stopper. The float does not come into contact with the end surfaces of the locking member, and the contact area with these end surfaces is significantly reduced, and the float is not attracted to the stopper or the end surface of the locking member due to wetting. Moreover, by reducing the amount of movement of the float in the axial direction, the operating characteristics of the float in the vertical direction are improved.

Furthermore, even when the float moves up and down in an inclined state, the end surface of the float does not come into contact with both end surfaces of the stopper and the locking member at the same time.
When the float is in contact with both end surfaces, the raising and lowering operation of one end surface of the float has already been completed. Therefore, since both end surfaces of the float do not perform the raising and lowering operation at the same time, the float is not engaged with the stopper. There is no possibility of getting caught on the end face of the member.

Therefore, according to the liquid level detector of the present invention, inoperation,
without causing inconveniences such as malfunctions or operation delays.
Smooth vertical movement is achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an embodiment of the liquid level detector according to the present invention, FIG. 2 is a schematic sectional view of the float portion in FIG. FIG. 4 is a schematic side view showing another embodiment. Fifth
The figure is a schematic cross-sectional view showing an example of a conventional liquid level detector. 10...liquid level detector, 11...stopper, 12...
Stem, 13...Reed switch, 14...Float, 14a, 14a', 14b, 14b'...Protrusion, 15...Ring.

Claims (1)

[Claim for Utility Model Registration] A stem extending horizontally inward from the inner end surface of a stopper to be attached to the side wall of a liquid tank and having a built-in reed switch; A horizontal type comprising a horizontal hollow cylindrical float formed so as to be light and fitted with play to the stem, and a magnet buried above or below the inner surface of the float. A liquid level detector, characterized in that at least one protrusion protruding outward in the axial direction is provided on the end face of the float on the side where at least the center of gravity is eccentric.