JPS58902Y2 - Seiden Yoriyoshiki Level Switch - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a capacitive level switch that performs a switching operation by detecting the surface level of a fluid.

A circuit block diagram of a capacitive level switch is shown in FIG.

This detects the change in capacitance between the electrode rod 101 and the ground terminal 102 due to the positional relationship between the surface level of a liquid, powder, etc. and the electrode rod 101, and performs a switching operation at a predetermined surface level. However, this circuit section is assembled using printed wiring or the like and housed inside the case.

By the way, such capacitive level switches are used in various forms, such as detecting the water depth of water tanks installed on the rooftops of high-rise buildings, so the case has to meet certain conditions such as water resistance and robustness. It must satisfy all of the following.

By the way, die-cast aluminum has traditionally been used as a case material that satisfies these conditions for this case, but as the price of this die-cast has skyrocketed, the cost of level switches has skyrocketed, making it difficult to supply them at a low price. It has become.

The present invention has been made in view of the above circumstances, and aims to provide a capacitive level switch that can be supplied at low cost, is easily miniaturized, and is also easy to manufacture and assemble.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4.

Figure 2 is an external side view of a capacitive level switch, Figure 3
The figure is a cross-sectional side view, and FIG. 4 is a partially cutaway plan view of the main part.

In these figures, a cylindrical rod-shaped electrode 1 is fixedly supported by a fixture 3 with an insulator 2 in between.

This fixing fitting 3 has a hexagonal columnar screw head 31 and a screw portion 32.
It has

The screw head 31 has a cavity inside, and the circuit part 5 is housed in this cavity.

By rotating this hexagonal columnar screw head 31 with a spanner or the like, the screw portion 32 is screwed and fixed to the mounting plate 6 such as the wall surface of the water supply tank.

Further, a lid 4 is screwed onto the screw head 31, and the circuit section 5 for sealing the internal cavity is fixed on a printed wiring board 8, and banana plug-shaped connection plugs 81 and 82 are connected to this printed wiring board. 8 is fixed at a predetermined position.

The connection plug 81 is inserted into the plug jack 11 of the electrode 1 to establish an electrical connection.

The connection plug 82 is inserted into the plug jack 33 of the fixture 3, and is electrically connected to the mounting plate 6 through the fixture 3 and grounded.

In the capacitive level switch having the above configuration, the circuit section 5 is housed inside the screw head 31 of the fixture 3 and is shielded from external electrical noise.

Further, the grounding terminal of the circuit section 5 is electrically connected to the fixture 3 through the connection plug 82, and connected to a water tank or the like through the screw section 32 and grounded.

Therefore, the tank body and the electrode rod form a capacitor,
The capacitance C of this capacitor changes depending on the dielectric constant of the fluid and the amount of fluid.

Therefore, the level detection operation is performed only by the capacitance change corresponding to the amount of the fluid having the predetermined dielectric constant, and a stable level detection operation occurs without being affected by other conditions.

In addition, the electrical connection between the circuit section 5 and the electrode 1 or the fixture 3 can be made with one touch using the connection plugs 81 and 82.
Easy to assemble.

Furthermore, since the screw head 31 of the fixture 3 is used as a circuit case, a compact and inexpensive level switch can be provided without requiring an aluminum die-cast circuit case or the like as in the conventional case.

Note that the present invention is not limited to the above embodiments, and various configurations are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

Figure 1 is a block circuit diagram of a capacitive level switch.
2 to 4 show an embodiment of the present invention, in which FIG. 2 is an external side view, FIG. 3 is a sectional side view, and FIG. 4 is a partially cutaway plan view of the main part. 101.1...Electrode, 102...Grounding terminal, 2...Insulator, 3...Fixing metal fitting, 31...Screw head Part, 32...Screw part, 4...Lid, 5...Circuit part, 8...
...Printed wiring board, 81.82...Connection plug, 11.33...Plug jack.

Claims (1)

[Scope of utility model registration request] an electrode rod, a level switch circuit section that performs a switching operation by detecting a change in capacitance between the electrode rod and a ground terminal due to the surface level of the fluid, and a container for storing the fluid that houses this circuit section and is insulated from the electrode rod. A capacitive level switch, comprising: a fixing fitting that can be attached to the level switch; and a connecting plug connected to a ground terminal of the level switch circuit section, the connecting plug being in contact with the fixing fitting. .