JPH11167850A - Float switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical float switch capable of detecting water level without malfunction. SOLUTION: An aperture is formed in the lower end face 7 of a pipe 2 vertically attached to a wall face of a tank 1 and an air hole 9 equipped with an externally opening type valve 10 is installed in the upper part, a cylinder 3 is installed in the center of the pipe 2, a reed switch 4 is built in near the lower end face 7 of the cylinder 3, and a float 6 containing a magnet 5 is fitted in the cylinder 3. Consequently, when water level rises, air in the pipe 2 is pushed out and when the water level lowers, the inside of the pipe 2 becomes negative pressure, so that the float 6 is kept constant and only at the time when the water level is lowered to the lower end face 7 of the pipe 2, air flows into the pipe 2 from the lower end face 7 and the float 6 descends to operate the reed switch 4 by the magnet 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a float switch for detecting a water level in a liquid container such as a tank.

[0002]

2. Description of the Related Art Conventionally, a float switch as shown in FIG. 3 has been used to detect a drought in a tank or the like. This float switch is a cylinder 13 in which a reed switch 12 is incorporated.
And a float 15 fitted into the outside of the cylinder 13 and incorporating a magnet 14, and attached to a wall surface of a tank 16.

The reed switch 12 and the magnet 14
Constitutes a proximity switch, and when the water level falls and the float 15 descends to the height position of the reed switch 12, the magnet 14 activates the reed switch 12 and sounds a buzzer or the like.

The float switch described above has a problem that when the liquid level in the tank 16 fluctuates due to vibration or the like, the float 15 moves up and down due to the fluctuation, and the switch is repeatedly turned on and off. To cope with this problem, a timer or the like is conventionally used, and a buzzer or the like is sounded when the float switch continues to be turned on for a predetermined time.

An object of the present invention is to provide an inexpensive float switch capable of detecting a water level without malfunction.

[0006]

In order to solve the above-mentioned problems, a float switch according to the present invention is mounted vertically in a liquid container and has an opening at a lower portion thereof. A configuration in which an arranged switch and a float that moves up and down in the pipe and has a switch operating means are provided, and an air hole is provided in an upper portion of the pipe, and a valve that opens to the outside of the pipe is attached to the air hole. It was adopted.

That is, when the water level rises, the float rises with the water level due to the liquid flowing from the lower opening of the pipe, and at this time, the air in the pipe rises due to the rise in the liquid level in the pipe, and the air in the air hole rises. The valve is opened and pushed out. When the water level drops, the valve is closed by the air that is going to flow into the pipe, and the inside of the pipe becomes negative pressure,
The liquid level in the pipe does not drop and the float remains in its original position. When the water level further lowers and reaches the lower opening position of the pipe, air flows into the pipe from this opening, and the liquid in the pipe flows out to lower the float.

Therefore, the float switch according to the present invention does not operate when the liquid surface is wavy, but only when the water level has dropped to the lower opening position of the pipe, the float having the switch operating means has the opening function. Activate the switch that is located in position.

An inexpensive float switch can be provided by using the reed switch and the magnet incorporated in the float as the switch and the operating means of the switch, respectively.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a float switch. In this float switch, a cylinder 3 is disposed at the center of a pipe 2 vertically mounted on a wall of a tank 1, a reed switch 4 is incorporated near a lower end of the cylinder 3, and a magnet 5 is incorporated in the cylinder 3. Float 6
Is fitted.

The pipe 2 has an open lower end surface 7.
Is mounted in accordance with the limit water level at which the tube 3 is detected, and the cylinder 3 is fixed to the closed upper end surface 8. An air hole 9 is provided near the upper end surface 8, and a valve 10 that opens outward is attached to the air hole 9. The valve 10 is made of an elastic body such as a rubber sheet, and normally closes the air hole 9. Further, a retaining ring 11 for preventing the float 6 from dropping is attached to a lower end of the cylinder 3.

Next, the operation of the float switch will be described with reference to FIG. Figure 2 (a) when the water level rises
As shown in the figure, the liquid 6 flowing from the lower end face 7 of the pipe 2 causes the float 6 to rise with the water level. At this time, the air in the pipe 2 rises due to the rise in the liquid level in the pipe 2 and the air holes 9 The valve 10 is opened and pushed out.

When the water level falls, as shown in FIG.
0 is closed and the inside of the pipe 2 becomes a negative pressure, so that the liquid level in the pipe 2 does not drop and the float 6 remains at the original position. When the water level further lowers and reaches the lower end face 7 of the pipe 2, as shown in FIG. 2C, air flows into the pipe 2 from the lower end face 7, and the liquid in the pipe 2 flows out. The float 6 is lowered, and the magnet 5 comes close to the reed switch 4 to activate the float switch.

In the above embodiment, the lower opening is provided on the lower end surface 7 of the pipe 2 and the air hole 9 is provided on the side surface near the upper end of the pipe 2. However, the lower opening is provided on the side surface near the lower end of the pipe 2.
May be provided on the upper end surface 8 of the pipe 2.

In the above-described embodiment, a proximity switch combining a reed switch and a magnet is employed. However, a contact type limit switch and a non-contact type photoelectric switch can also be employed. For example, in the case of a limit switch, a micro switch can be installed at the lower end of a pipe, and its operating lever can be pressed with a float.In the case of a photoelectric switch, a light emitter and a light receiver are opposed to the lower end of the pipe. It is possible to arrange such that the space between the light emitter and the light receiver is blocked by a float.

[0016]

As described above, according to the float switch of the present invention, an opening is provided at a lower portion of a pipe vertically mounted in a liquid container, and an air hole having an open valve is provided at an upper portion. By disposing a switch near the lower opening of the pipe and incorporating a float having the switch operating means inside the pipe, the air in the pipe is pushed out when the water level rises, and the pipe is pushed when the water level falls. Use the negative pressure inside to hold the float,
Only when the water level reached the limit water level at the lower opening position of the pipe, air flowed into the pipe from this lower opening, the float descended, and the switch was operated, so
An erroneous operation of the float switch due to waving of the liquid surface in the liquid container can be prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a state in which a float switch according to an embodiment is mounted in a tank.

FIGS. 2A, 2B and 2C are cross-sectional views illustrating the operation of the float switch of FIG. 1;

FIG. 3 is a longitudinal sectional view showing a state in which a conventional float switch is mounted in a tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tank 2 Pipe 3 Tube 4 Reed switch 5 Magnet 6 Float 7 Lower end surface 8 Upper end surface 9 Air hole 10 Valve 11 Retaining ring 12 Reed switch 13 Tube 14 Magnet 15 Float 16 Tank

Claims (2)

[Claims] 1. A pipe vertically mounted in a liquid container and having an opening at a lower part thereof, a switch arranged near the opening of the pipe, and a vertically moving pipe.
A float having actuation means for the switch,
A float switch in which an air hole is provided at an upper portion of the pipe, and a valve that opens to the outside of the pipe is attached to the air hole. 2. The switch and a switch operating means,
The float switch according to claim 1, wherein each of the float switch and the magnet is a magnet incorporated in the float.