JPS61231416A - Galvanometer - Google Patents

Abstract

PURPOSE:To electrically accurately detect a flow amount without being affected by viscosity or the foreign matter in a fluid, by providing a sensor which is present in the downstream side of the electrode provided in the piping of an electric insulating fluid and detecting the charge of the charged fluid. CONSTITUTION:When a switch 3 is closed, predetermined voltage is applied between electrodes 2, 2 to charge the electric insulating fluid flowing through piping 1 and, at the same time, a gate circuit 11 is opened to allow a counter 12 to start the counting of the clock pulse from a clock pulse generator 10. When the charged fluid moves and the charge thereof is detected by the first charge detection terminal 7 of a charge detection sensor 5, charge having polarity inverse to that of a second charge detection terminal 8 is induced in said detection terminal 8 to output a gate closing signal to the gate circuit 11 from an amplifier 9. Therefore, the count value of the counter 12 corresponds to the time required in allowing the fluid to reach the sensor 5 from the electrodes 2, 2 and predetermined operation is performed in an operation circuit 13 to display a flow amount/min on a display device 14.

Description

[Detailed description of the invention] [Field of application of the invention] This invention relates to galvanometers, and more particularly.

This field relates to a galvanometer that electrically detects the flow rate of electrically insulating fluid such as lubricating oil used in machine tools and the like.

[Technical Background of the Invention] In conventional galvanometers, a mechanical floating resistor is generally inserted into the pipe, and the movement of the resistor due to the differential pressure between the primary pressure side and the secondary pressure side is controlled using, for example, a magnet. Detection is done using a combination of reed switches or a differential transformer. This kind of galvanometer.

When the flow rate is large or the fluid has high viscosity, a large force acts on the floating resistor to move it, so the flow rate can be detected very accurately.However, when the flow rate is small or the viscosity is high, is low.

Since the floating resistor moves slowly, it becomes difficult to accurately measure the flow rate. In order to solve this problem, it is possible to reduce the clearance between the inner diameter of the pipe and the floating resistor, but this also means that even extremely fine foreign objects of about 30 μm mixed in the fluid can become suspended. There is a high possibility that the resistor may malfunction.

Further, in cases where fluid is supplied intermittently, the floating resistor returns slowly when the supply pump is stopped, and a situation may arise in which it is not possible to respond accurately to the intermittent cycle.

Furthermore, the detection accuracy of this type of galvanometer is greatly influenced by the viscosity of the fluid. i.e. summer 40'C
Considering the temperature at 0°C in the winter, an oil with an ISO viscosity grade of VG68 will have a viscosity of 68 cSt in the summer and 1100 cSt in the winter, which means the viscosity will change by about 16 times.

Since the force acting on the floating resistor changes greatly, it works well in the summer, but it also has the problem of slow response in the winter.

[Object of the invention] This invention was made in view of the above-mentioned conventional drawbacks,
The purpose is to provide a galvanometer that can accurately electrically detect the flow rate without being affected by the viscosity of the fluid or the presence of foreign matter in the fluid.

[Structure of the Invention] That is, the galvanometer of the present invention includes an electrode provided in an electrically insulating fluid pipe, and a predetermined voltage applied to this electrode via a suitable switch means to charge the fluid. An output including a power source, a charge detection sensor located downstream of the electrode and detecting the charge on the fluid, and an amplifier connected to the charge detection sensor, and output from the amplifier. It is characterized in that the flow of fluid from the electrode to the charge detection sensor is detected based on a signal.

[Examples] Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings.

This detector is designed for use with electrically insulating fluids that do not lose a given charge, such as lubricating oil used in machine tools, and according to the embodiment shown in FIG. It comprises a pair of electrodes 2.2 arranged in the pipe 1 through which the electrically insulating fluid flows. In this case, each electrode 2, 2 is connected to a DC power source 4 via a suitable switch 3, and by closing the switch 3, a predetermined voltage is applied to each electrode 2, 2, and the fluid flowing therethrough is It is now electrically charged.

A charge detection sensor 5 is provided on the downstream side of each of the electrodes 2, 2 to detect the charges charged in the fluid as described above. As illustrated in FIG. 2, this charge detection sensor 5 has a first charge detection terminal 7 formed on the surface of a dielectric material 6 such as glass.

a second charge detection terminal 8 buried inside the dielectric 6, and each charge detection terminal 7, 8 is connected to a lead wire 7a,
8a to different input terminals of the amplifier 9.

In this embodiment, a clock pulse generator 10;
A counter 12 connected to the clock pulse generator 10 via a gate circuit 11, an arithmetic circuit 13 that calculates a flow rate based on the count counted by the counter 12, and a circuit connected to the output side of the arithmetic circuit 13. By controlling the gate circuit 11 with the closing signal of the switch 3 and the output signal from the amplifier 9,
I am trying to measure the flow rate.

That is, when the switch 3 is closed, a predetermined voltage is applied between each electrode 2°2 to charge the fluid, and at the same time, the gate circuit 11 is opened and the counter 12 receives the clock from the clock pulse generator 10. Pulse counting begins. The charged fluid moves and the charge is transferred to the charge detection sensor 5.
When captured at the first charge detection terminal 7 of the charge detection terminal 7, charges of opposite polarity are induced in the second charge detection terminal 8, thereby causing the gate circuit 11 from the amplifier 9 to close the gate. A signal is output. Therefore, the count value of the counter 12 is the time it takes for the fluid to reach the charge detection sensor 5 from the electrodes 2, 2. For example, the count value is t [sec
], the distance between the electrodes 2, 2 and the charge detection sensor 5 is Q, and the radius of the pipe 1 is r, then in the calculation circuit 13, for example ((π
The calculation r2XQ)/1)X60 is performed, and the display 1
4 displays the flow rate per minute.

Note that, especially when the flow rate of the fluid is high, it is expected that noise charges will be generated on the surface of the single load detection sensor 5 due to frictional resistance with the fluid. It is preferable to determine the function value of the amplifier 9 to prevent malfunction. It is also possible to automatically measure the flow rate at each time by turning on the switch 3 at predetermined time intervals using a timer (not shown).

FIG. 3 shows a modified embodiment of the invention. That is, in this modified embodiment, a pipe 1' made of a conductive material such as copper or iron is used, and in such a case, one electrode 2' is provided in the pipe 1' to For example, connect to the positive terminal side of the DC power supply 4, and
It is sufficient to connect the negative electrode side to the pipe wall of the pipe 1' and to the common wiring. Further, as the charge detection sensor, for example, a charge detection terminal 5' such as a mesh or a punching plate can be used, and this charge detection terminal 5' is connected to one input terminal of the amplifier 9, and the amplifier The other input terminal 9 is preferably connected to the pipe wall of the pipe 1'.

Furthermore, according to this modified embodiment, the output signal of the amplifier 9 is used to monitor, for example, whether lubricating oil is being properly supplied to the oil supply point of the machine tool.

That is, the output terminal of the amplifier 9 is connected, for example, to the clear terminal OL of the down counter 15, and by opening and closing the switch 3 at appropriate timing, the down counter 15 is controlled by the clock pulse input from the clock terminal CK. When performing a counting operation, the count is cleared before the count value becomes less than the reference count value. therefore.

If lubricating oil is not being sent, the clear signal is not output from the amplifier 9, so the count value reaches the reference count value and the down counter 15 outputs a stop signal for the machine tool, which prevents accidents such as seizure. We are trying to prevent this from happening.

[Effects] As is clear from the above description of the embodiments, according to the present invention, even extremely small flow rates can be accurately detected without being affected by the viscosity of the fluid or foreign substances contained therein. The present invention provides a galvanometer that is particularly suitable for lubricating oil supply systems for ultra-precision processing machines and the like.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is an enlarged sectional view of the charge detection sensor shown in FIG. 1, and FIG. 3 is a schematic circuit diagram showing a modified embodiment of the invention. In the figure, 1 and 1' are pipes, 2 and 2' are electrodes, 3 is a switch, 4 is a power supply, 5 is a charge detection sensor, 9 is an amplifier, 10 is a clock pulse generator, 11 is a gate circuit, and 12 1 is a counter, 13 is an arithmetic circuit, and 14 is a display. Patent applicant: Seiwa Yuuki Hanuri Co., Ltd. Agent: Patent attorney: Takuya Ohara Figure 1

Claims (1)

[Scope of Claims] A galvanometer for detecting the flow rate of electrically insulating fluid such as lubricating oil, comprising an electrode provided in a pipe through which the electrically insulating fluid flows, and a switch means on the electrode. a power source that charges the electrically insulating fluid by applying a predetermined voltage via the electrically insulating fluid; a charge detection sensor located downstream of the electrode that detects the electrical charge on the electrically insulating fluid; and an amplifier connected to the detection sensor, and detects the flow of the electrically insulating fluid from the electrode to the charge detection sensor based on an output signal output from the amplifier. vessel.