JPH0392687A - Motion confirming mechanism fop direction control valve - Google Patents

Abstract

PURPOSE:To facilitate confirmation of the motion of a flow by a method wherein a sensor having a detecting element to detect the presence of the flow of fluid is disposed between a direction control valve in an air pressure circuit and a drive device driven by the direction control valve. CONSTITUTION:A sensor 1 is disposed in a piping 2 with which a flow passage running between a direction control valve and a drive device driven by the direction control valve is formed. A detecting element 3 of the sensor 1 is formed of a resistance type temperature sensitive element, and is secured in a holder 4, formed of a material having excellent chemical resistance, by means of a securing material 5 having excellent thermal conductivity and insulating ability. A holder 4 is inserted in a screwing-in manner into the piping and secured by means of a nut 6, and the element 3 is caused to front on a flow passage in the piping 2. When air is fed in the piping 2 and the flow of air is generated, an amount of heat radiated through the holder 4 and the securing material 5 is increased, resulting in the change of the resistance value of the element 3. The change of the resistance value is measured to detect the presence of the flow of air.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the operation of a directional control valve in a pneumatic circuit, that is, the presence or absence of air flow downstream of the directional control valve, the flow rate,
This relates to an operation confirmation mechanism for confirming flow rate, etc.

[Prior Art] Pneumatic circuits in recent automated lines are often designed with high density as directional control valves, cylinders, etc. become smaller. Since such pneumatic circuits are extremely complex, it is necessary to check the operation of each component for maintenance management.

As a means of confirming the above-mentioned operation, magnetic sensors are often used for actuators such as cylinders, and their operation has been confirmed without any problems. However, for directional control valves, a fully satisfactory method has not been proposed. Not yet.

For example, a semiconductor switch using a silicon chip, etc.
Although it has high sensitivity, the structure is complex and it is difficult to miniaturize.
Furthermore, reed switches and diaphragm switches are also difficult to miniaturize, making them difficult to use for this purpose.

[Problems to be Solved by the Invention] The functions required of a means for confirming the operation of a directional control valve are basically that its confirmation output can be obtained as an electrical signal for various controls; It is necessary to detect the fluid flow itself on the output side, taking into account not only the movement of the valve element or its valve operating part itself, but also their failure. Moreover, with the increase in density mentioned above,
Recently, directional control valves have become increasingly manifold-based, and there is a need for an operation confirmation mechanism that is compact, long-life, and easy to structure and install.

A technical object of the present invention is to obtain an operation confirmation mechanism for a directional control valve that does not satisfy such requirements.

[Means for Solving the Problems] In order to solve the above problems, the operation check machine of the present invention is designed to check whether or not there is a fluid flow between a directional control valve in a pneumatic circuit and a drive device driven and controlled thereby. It is characterized in that a sensor is provided with a detection element for detecting the temperature, and the detection element is constituted by a resistance type temperature sensing element.

The above sensor is attached to the valve body of the directional control valve. 11 is attached to the valve body.

[Function 1] A detection element consisting of a resistance type thermosensor generates heat when a constant current is supplied, and the amount of heat generated and the amount of heat dissipation are stable in an equilibrium state, but the amount of heat dissipated is increases, and the temperature at equilibrium changes. On the other hand, the resistance value of a temperature sensing element varies depending on the temperature, and therefore, by measuring the resistance value of the temperature sensing element, it is possible to detect the presence or absence of a fluid flow, as well as the flow velocity and flow.

In addition, since a resistance type temperature sensing element is used particularly for detecting the flow of the fluid, it is possible to obtain an operation confirmation mechanism that is small, has a long life, and is simple in structure and installation.

[Example] FIG. 1 illustrates the basic configuration of an operation confirmation mechanism according to the present invention.

This operation confirmation mechanism confirms the operation of the directional control valve in the pneumatic circuit by detecting the presence or absence of air flow downstream of the directional control valve, the flow velocity, the flow rate, etc.
A sensor 1 for this detection is disposed in a pipe 2 that forms a flow path between the directional control valve and a driving device controlled by the directional control valve.

- The detection element 3 in the sensor 1 is formed of a resistance type temperature sensing element, and it is placed inside a holder 4 made of a material with excellent chemical resistance, and a fixing material 5 with excellent thermal conductivity and insulation properties. The holder 4 is screwed into the pipe 2 and fixed with nuts 1 and 6, so that the detection element 3 faces into the flow path inside the pipe 2.

As the resistance type temperature sensing element that constitutes the detection element 3, N
It is desirable to use either a TC thermistor, a PTC thermistor, or a platinum resistor. These are extremely simple and compact in structure and are ideal for checking the operation of pneumatic circuits.

In the operation confirmation mechanism having the above configuration, the detection element 3
When a constant current is supplied to the device in air, it generates heat depending on its resistance value, and stabilizes in a state where the amount of heat generated and the amount of heat dissipation are balanced. At this time, the amount of heat dissipated from the temperature-sensitive element varies depending on radiation, convection, etc., but in particular, the amount of heat dissipated changes due to the occurrence of convection due to the flow of the surrounding air, and accordingly, the amount of heat generated and the amount of heat dissipated change. The temperature at which equilibrium is reached changes.

On the other hand, it is known that the resistance value of this temperature-sensitive element varies depending on the temperature. Therefore, when measuring the resistance value of an element while supplying a constant current in the air, the resistance value gradually changes after the current is applied and soon reaches a constant value.

Such a temperature sensing element is placed in the piping 2 described above, and when air is supplied to the piping 2 by the force direction control valve and an air flow is generated, Q dissipates through the holder 4 and the fixing material 5. fJ increases, thereby detecting element 3
resistance value changes. Therefore, by measuring the resistance value of the temperature sensing element, it is possible to detect the focus of the air flow, as well as the flow velocity and flow rate.

[3 Figure 2A shows the output waveform of the pressure inside the piping when an NTC thermistor is used as the detection element and air flow is generated in the detection element, and Figure 2B shows the output waveform of the pressure in the pipe. This is the output waveform of the detection element that changes with the change. FIG. 3C shows a measurement circuit diagram when the above-mentioned NTC thermistor is used as the detection element 3.

31aA-C show similar waveforms and measurement circuit diagrams using a PrC thermistor as the detection element 3.

In this manner, since the temperature sensing element can easily convert changes in its resistance value into voltage or current, the presence or absence of flow can be easily detected as an electrical signal.

Furthermore, since the magnitude of the output of the temperature sensing element changes linearly depending on the magnitude of the fluid flow, the flow velocity and flow rate of the fluid can be detected.

Note that other resistance type temperature sensing elements can also be used within the range of simple structure and miniaturization, and similar detection in the pneumatic circuit can be performed using them as well.

The above-mentioned operation confirmation mechanism can be built into the directional control valve itself. FIG. 4 shows an example of the structure of the directional control valve.The valve main valve 10 is provided with a valve seat 13 that is opened and closed by a valve body 12 driven by a solenoid 1l, and the sensor 1 is attached to this valve seat. The detection element 3 is attached to the valve body 10 on the output side of the valve l3, and its detection element 3 faces the flow path within the valve body 10. Note that the configuration of the sensor itself is the same as that of the previously described embodiment.

When the directional control valve is configured in this way, when a fluid flow occurs on the output side of the valve seat 13 as the valve body l2 is driven,
As described above, the output of the detection element 3 changes, making it possible to confirm the operation of the directional control valve.

Note that the above sensor can be applied not only to directional control valves that perform on-off operations, but also to control valves that obtain a proportional output.

F. Effects of the Invention] As detailed above, according to the present invention, it is possible to obtain an operation confirmation mechanism that is compact, long-life, and easy to structure and install, compatible with manifolding of directional control valves, etc. As a result, it becomes possible to easily check the operation of the fluid flow by the directional control valve, and the equipment can be controlled reliably and stably.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts illustrating the basic configuration of the operation confirmation mechanism according to the present invention, and FIGS. 2A and B show NT as a detection element.
A waveform diagram of the pressure inside the pipe and the corresponding output of the detection element when a C thermistor is used, Figure C is a measurement circuit diagram when the above NTC thermistor is used, and Figures A to C are the detection element when the PTC thermistor is used. In this case, FIGS. 2A to 2C are waveform diagrams and measurement circuit diagrams, and FIG. 4 is a sectional view of a directional control valve incorporating an operation confirmation mechanism. 1...sensor, 3...detection element, 10...valve body, 12...valve body, 13...valve seat. Figure 2

Claims (1)

[Claims] 1. A sensor equipped with a detection element for detecting the presence or absence of fluid flow is disposed between the directional control valve in the pneumatic circuit and the drive device driven and controlled by the directional control valve, and the above-mentioned An operation confirmation mechanism for a directional control valve, characterized in that a detection element is constituted by a resistance type temperature sensing element. 2. The direction according to claim 1, characterized in that the valve body of the directional control valve is provided with a valve seat that is opened and closed by a valve body, and a sensor is attached to the valve body on the output side of the valve seat. Control valve operation confirmation mechanism.