JPH0329707Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a liquid level meter that detects changes in liquid level by converting them into electrical signals by vertical movement of a float.

(Prior art) The remaining amount of oil, etc. stored in a tank can be determined, for example, by floating a float in the tank and transmitting the vertical movement of the float to the sliding resistance, as shown in Japanese Utility Model Application Publication No. 56-61420. It is measured using a float-type liquid level gauge that converts the signal into an electrical signal.

However, since the sliding piece moves on the surface of the resistance board by sliding motion, the frictional force is large, and hysteresis occurs between changes in the liquid level and the detector output, resulting in low measurement accuracy and minute level changes due to leaks, etc. There was a problem in that not only was it impossible to detect, but also that the indicated value was likely to fluctuate due to the float oscillating due to ripples in the liquid surface.

(Objective) In view of such problems, the present invention aims to provide a liquid level gauge that can accurately convert minute changes in the liquid level into electrical signals.

(Means for Achieving the Object) That is, the present invention is a liquid level gauge for achieving the above object, which has a large number of liquid passage pores in the lower part, and which are fitted together so that a gap is formed between them. A float with a rod long enough to reach the inside of the displacement detector is installed in the float guide tube, which is made up of double inner and outer tubes. In addition to fixing a detected object equipped with a roller that rolls into contact with the detected object, an adjustment mechanism that moves and adjusts the roller in the radial direction is provided on the detected object to adjust the contact pressure between the roller and the electric resistor. This is what I did.

(Function) With this configuration, fluctuations in the liquid level transmitted to the float are attenuated and absorbed by the gap formed between the liquid passage hole provided at the bottom and the inner and outer tubes, and the contact pressure is also reduced. By rolling a roller that is adjusted to a constant value on an electric resistor, the float faithfully follows the liquid level and transmits the information to the displacement detector with high precision.

Therefore, details of the present invention will be explained below based on illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, in which reference numeral 1 denotes a float guide whose upper part protrudes from an oil tank T, a stand 2 is provided at its lower end, and which is disposed vertically within the tank. A tube made of two tubes 3 and 4 of different diameters with a large number of small holes 3a and 4a bored in the lower part, arranged coaxially with an interval in the radial direction, and a rod 5 is implanted. It is constructed by accommodating a float 6 so as to be movable up and down. Reference numeral 7 denotes a displacement detector that converts changes in the liquid level into electrical signals, and is attached to the upper part of the float guide tube 1 by fitting a cylindrical base 8 into it. Grooves 9, 9 (FIG. 2 A) are formed, and an electric resistor 10 is provided on the inner surface of the grooves with an electric insulating layer 10a interposed therebetween.
A detection object 11 is attached to the upper part of the float 6 and is configured to move while rolling on the surface of the electric resistor 10 in accordance with the vertical movement of the float 6.

FIG. 2 shows an embodiment of the displacement detector 7 described above, and the reference numeral 12 in the figure is a case housing a crank mechanism, which will be described later.
It is horizontally attached to the rod 5 by a, and is configured with guide holes 13, 13 bored at two locations symmetrical about the central axis. 14 is the above-mentioned crank mechanism, and a disk 16 is attached to the lower part of the adjusting screw 15 whose surface is protruded from the center of the case 14.
A pair of crank pins 17, 17, crank 18,
18, guide hole 1 via crank pins 19, 19
Crank cylinder 20 movably inserted into 3,
20. The crank cylinders 20, 20 have coil springs 21,
21 is accommodated, and one end of push rods 22, 22 is inserted so as to be freely slidable in the radial direction. At the other ends of the push rods 22, 22, rollers 23, 23 formed of a conductive material such as metal are mounted on bearings 2.
4 and 24 so as to be rotatably attached.

Returning to FIG. 1 again, a contact terminal 25 is provided at the upper end of the electric resistor 10 to connect a lead wire, and a coil lead 26 is connected to the push rod 22 to set the fixed resistances R ₁ and R ₂ and the reference value. Resistance Rs
Together with Wheatstone Bridge. In addition, the reference numeral 27 in the figure indicates a potentiometer connected to the Wheatstone bridge, and 28 indicates a cover plate.

In this embodiment, when the adjusting screw 15 is rotated from above with a tool such as a screwdriver with the detected object 11 housed in the cylindrical base 8, the crank cylinders 20, 20 are rotated via the crank mechanisms 14, 14. moves in the radial direction, and the pressing force of the coil springs 21, 21 housed inside changes in the outer radial direction. This pressing force is
It acts on the rollers 23, 23 via 2, 22, and changes the contact pressure with the electric resistors 10, 10. In this state, while moving the slider 11 up and down, the adjusting screw 15 is fixed at a location where the roller smoothly moves in the axial direction.

When the apparatus is operated after such adjustment is completed, the detected object 11 is moved by the float 6 to a position corresponding to the liquid level, and outputs a resistance value corresponding to the liquid level. At this point, while watching the potentiometer 27, adjust the reference value setting resistor Rs to balance the Whiston bridge.

In such a state, tank T or
If a minute leak occurs in the conduit extending from now on, the liquid level in the tank T will gradually drop as time passes, and the float 6 will follow this and descend. At this time, the conductive rollers 23, 23 forming the detected object 11 smoothly descend while rolling on the surfaces of the electrical resistors 10, 10, and the output resistance value changes. This causes the bridge to become unbalanced, activating an alarm (not shown) to prompt inspection. In this state, when mechanical vibration is applied to the tank and the liquid level moves up and down, the change in the liquid level tends to propagate into the guide tube 1, but the pores 3a formed in the guide tube 1 , 4a, and between pipe 3 and pipe 4
As a result, the float 6 is sufficiently damped by the damping, and the liquid level does not fluctuate, and the float 6 remains stationary at the liquid level.

In addition, if the electrical resistor or conductive roller becomes worn due to long-term use, the adjustment screw 15 can be rotated to increase the pressing force to remove looseness and restore it properly. The surface of the electrical resistor 10 can be moved smoothly with a sufficient contact pressure.

In the embodiment described above, the rotation of the adjusting screw 15 is converted into a movement in the radial direction by the crank mechanism, but a cam plate is attached to the adjusting screw and the cylinder is pressed through the cam follower. The same effect can be obtained even if

Furthermore, in the above-described embodiments, the leakage of the tank and the pipe extending therefrom was explained as an example, but it goes without saying that it can also be used as a monitor to constantly monitor the liquid level of the tank.

It goes without saying that the resistor shown in FIG. 2 can be used not only for detecting the displacement of a float floating on the liquid surface, but also as a converter for detecting the displacement of any moving object as an electrical signal.

(Effects) As described above, according to the present invention, the guide tube of the float is composed of two inner and outer tubes that are fitted together with a gap between them, and a large number of tubes are arranged at the bottom of these tubes. Because liquid passing pores are provided, even if the liquid level fluctuates during liquid supply or due to vibrations applied to the tank, this movement is attenuated by the frictional resistance when the liquid passes through the pores. This movement can be absorbed by the damper effect provided by the gap between the tubes, so that only level fluctuations based on changes in the amount of liquid in the tank are properly transmitted to the float.

Furthermore, since a roller is provided on the object to be detected so that it rolls into contact with the electric resistor on the inner surface of the displacement detector, it is possible to accurately transmit the displacement of the liquid level converted by the float to the displacement detector. Not only is this possible, but the adjustment mechanism provided on the detected object adjusts the movement of the roller to apply a constant contact pressure to it, so by adjusting the contact pressure appropriately, it can be used for a long period of time. It is possible to detect minute changes in the liquid level with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a device showing an embodiment of the present invention, and FIGS. 2A and 2B are a top view and a sectional view, respectively, showing an embodiment of a displacement detector used in the same device. . 1...Float guide pipe, 3, 4...Pipe, 3
a, 4a... Pore, 5... Rod, 6... Float,
10... Electric resistor, 11... Slider, 23...
Laura, T...Tank.

Claims (1)

[Scope of utility model registration request] A float guide tube consisting of an inner and outer double tube, which has a large number of liquid passage pores at the bottom and which are fitted together so as to form a gap between them, has a length that reaches the tip end into the displacement detector. A float equipped with a rod is installed inside the float, and a detected object equipped with a roller that rolls into contact with the electrical resistor on the inner surface of the displacement detector is fixed to the tip of the rod, and the roller and the detected object are fixed to the tip of the rod. A liquid level gauge provided with an adjusting mechanism that moves and adjusts the roller in a radial direction to adjust the contact pressure with the electric resistor.