JP2000207029A - Flow rate controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive flow rate controller capable of controlling the flow rate of fluid by a simple signal. SOLUTION: Plural orifices 4 set so as to obtain different flow rates against the set pressure of an air pressure source 1 are mutually parallelly connected to the source 1. Plural valves 5 in an opening/closing operation shape are respectively serially connected to the orifices 4. A spray nozzle 7 is connected to the valves 5, and the fluid of a flow rate decided by the combination of orifices 4 selected by the opening operation of the valves 5 is supplied to the nozzle 7. When the flow rate needed by the nozzle 7 is inputted to the an operation control part 8, the part 8 controls the opening and closing of the respective valves 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control device for controlling a flow rate of a fluid.

[0002]

2. Description of the Related Art Conventionally, in an air flow control device for a two-fluid spray nozzle that pulverizes and atomizes a liquid with air, the pressure of air supplied to the spray nozzle is reduced by a manual pressure reducing valve from a set pressure of an air pressure source. The air flow is controlled by changing the air flow.

In this conventional apparatus, since the flow rate of air is controlled by pressure control using a manual pressure reducing valve, the air flow rate cannot be controlled by an electric signal.

For this reason, for example, in a spray fluxer or the like, the application conditions for each substrate to which the flux is applied are stored in an electric storage device, and this is automatically applied to each substrate production. Alternatively, it is impossible to change the air flow rate over time.

[0005] On the other hand, there is a commercially available pressure reducing valve that changes the secondary pressure thereof according to the voltage or current applied to the pressure reducing valve. If this is used, the air flow rate can be controlled by an electric signal.

[0006]

However, when this is used in a spray fluxer or the like, a voltage or current is output as a control value to a pressure reducing valve, so that a sequencer often used for controlling this type of apparatus is used. In addition, it is necessary to incorporate or attach an expensive D / A conversion circuit as a component of the device, and there has been a problem that the marketability of the device is deteriorated. In addition, in such a method, the obtained air flow rate control has high accuracy, but the air flow rate control of the spray nozzle is excessively accurate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an inexpensive flow control device which can control the flow rate of a fluid by a simple signal.

[0008]

SUMMARY OF THE INVENTION According to the first aspect of the present invention, there are provided a plurality of orifices which are set so as to obtain different flow rates with respect to the same fluid pressure and which are connected in parallel with each other; A flow control device comprising: a plurality of valves of an opening / closing operation type, each of which is connected in series and controls a flow rate of a fluid by a combination of orifices selected by an opening operation.

By controlling the opening and closing of a plurality of valves by simple ON / OFF signals, the combination of a plurality of orifices having different flow characteristics is changed, and the flow rate of the fluid is controlled in multiple stages.

According to a second aspect of the present invention, there is provided the flow control device according to the first aspect, further comprising an arithmetic control unit that controls opening and closing of each valve by inputting a required flow rate.

When the required flow rate is input to the arithmetic and control unit, the arithmetic and control unit automatically controls the opening and closing of each valve and automatically changes the combination of orifices.

According to a third aspect of the present invention, there is provided a fluid pressure source, a plurality of orifices set so as to obtain different flow rates with respect to a set pressure of the fluid pressure source, and connected to each other in parallel. A plurality of open / close-operated valves respectively connected in series to the orifices, a spray nozzle that supplies a fluid at a flow rate determined by a combination of the selected orifices by opening these valves, and a spray nozzle that is required. And a calculation control unit that controls the opening and closing of each valve according to the input of the flow rate.

When the flow rate required by the spray nozzle is input to the arithmetic and control unit, a plurality of valves are respectively controlled to open and close by a signal from the arithmetic and control unit, and the fluid supplied from the fluid pressure source opens the valve. The spray is supplied to the spray nozzle through a combination of orifices selected by operation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS.

As shown in FIG. 1, an inlet manifold 2 is connected to an air pressure source 1 as a fluid pressure source having a pressure setting portion 1a, and a plurality of, ie, n, passages 3 ₁ are connected to the inlet manifold 2. , 3 ₂ , 3 ₃ , 3 ₄ ,..., 3 _n are connected in parallel.

The inlet-side manifold 2, the air as a fluid which is supplied from the air pressure source 1 is controlled flow rate, each of the passages 3 _1, 3 _2, 3 _3, 3 _4, distributed evenly ...... 3 _n I do.

Each of these passages 3 ₁ , 3 ₂ , 3 ₃ , 3
₄ ,..., 3 _n include a plurality of orifices 4 ₁ , 4 ₂ , 4.
4 ₃ , 4 ₄ ,... 4 _n (hereinafter, simply referred to as the orifice 4) and a plurality of open / close-operated valves 5 interposed in each passage.
₁ , 5 ₂ , 5 ₃ , 5 ₄ ,... 5 _n (hereinafter simply referred to as valve 5) are arranged in series.

Each of the orifices 4 is, under a predetermined set pressure of the air pressure source 1, sequentially Q.1, Q.2, Q.4,
Q · 8,... Q · 2 ⁿ (n is an arbitrary integer, Q is a unit flow rate), are set to different opening areas so as to obtain different flow rates.

Each of the valves 5 controls the flow rate of the fluid by a combination of the orifices 4 selected by the opening operation, and is connected to an outlet manifold 6 for collecting air from each of the valves 5. The manifold 6 is connected to a two-fluid spray nozzle (hereinafter, simply referred to as a spray nozzle) 7 that pulverizes and atomizes the liquid with air.

Further, each valve 5 is electrically turned on / off.
An electrical operation unit such as a solenoid that is turned off includes an arithmetic control unit 8 that controls opening and closing of a valve 5 corresponding to an arbitrary orifice 4 in accordance with an input value of an air flow required by the spray nozzle 7, and an electric wire 9 _1. , 9 ₂ , 9 ₃ , 9 ₄ ,... 9 _n .

When a flow rate command is given to the arithmetic and control unit 8, the arithmetic and control unit 8 determines the opening and closing of each valve 5 so as to obtain the flow rate in response to the set flow rate command of Q · 2 ^n. Then, an open command or a close command is output to each of the n valves 5.

Thus, a flow of air determined by the combination of the orifices 4 selected by the opening operation of the plurality of valves 5 is supplied to the spray nozzle 7.

As described above, by opening and closing each valve 5 connected to each orifice 4 in response to a signal from the arithmetic and control unit 8, the minimum unit for setting the flow rate is Q, which is an integral multiple of two. An appropriate air flow is discharged from the outlet of the outlet side manifold 6.

In short, in the control of the atomizing air flow rate of the spray nozzle 7 for pulverizing and atomizing the liquid with air,
A plurality of orifices 4 connected in parallel to the pneumatic pressure source at a flow rate of Q · 2 ⁿ (n is an arbitrary integer, Q is a unit flow rate) and a valve 5 connected in series to each orifice 4 And an arithmetic and control unit 8 that controls the opening and closing of each valve 5 according to the input value of the air flow rate, thereby controlling the air flow rate.

In the above-described apparatus, the air flow control is performed by setting each of the valves 5 to a fully opened state or a fully closed state. Therefore, the purpose of the air flow rate control is achieved by an on / off signal from the sequencer. It is not necessary to use an expensive D / A conversion circuit to provide the same function, and the cost for the apparatus can be saved.

In place of the plurality of orifices 4 having different flow characteristics as described above, a plurality of orifices having the same amount of air flow characteristics are used in parallel, and the number of valves in the open state is changed. but, although the air flow control is possible, in such a case, in order to control the flow rate of 2 ⁿ stages air requires 2 ⁿ pieces of orifices and valves, but costly, as described above By using a plurality of orifices 4 having different flow characteristics in combination, it is possible to perform a very multi-stage flow control of 2 ⁿ stages including fully closed by n orifices 4 and valves 5 in detail. The cost of the apparatus can be reduced.

[0027] Figure 2, the flow rate under a set pressure of the pressure source 1 of the orifice 4 ₁ connected to the left end of the valve 5 ₁ 1,
The relationship between the opening and closing of each valve 5 and the flow rate when the number of each valve 5 and orifice 4 is 5, that is, when n = 5, is shown.

In the spray nozzle 7 generally used in a spray fluxer to which the present apparatus is mainly applied, fine particles discharged from the spray nozzle 7 are controlled by controlling the flow rate of supplied air. It is possible to change the particle size of the flux.

By applying this apparatus to a spray fluxer, the return shower onto the component mounting board to be soldered is disliked, and the flow rate of air supplied to the spray nozzle 7 is increased in order to obtain the finest possible flux particles. In some cases, such as when soldering to a through hole of a substrate is required and a relatively large particle diameter is obtained, the flow rate of air supplied to the spray nozzle 7 is reduced, and in some cases, an electric signal is used to manually operate the pressure reducing valve. The desired application state can be obtained by changing the air flow rate without any operation.

During the application of the flux, the spray nozzle 7
If the flow rate of the supplied flux and the flow rate of the supplied air are simultaneously or individually changed, it is possible to apply a suitable flux to a part of the substrate.

In a conventional apparatus in which the flow rate of air is controlled by a manual pressure reducing valve, it is impossible to automatically change the coating conditions and arbitrarily change the coating conditions during coating.

When a spray nozzle having a self-priming property by air supply is used in the spray fluxer, the liquid supply line of the spray nozzle 7 is connected to the IPA (iso-propyl alcohol) from the flux supply pipe at any time. ), The maximum flow rate of air is given to the spray nozzle 7 by controlling the air flow rate by the present apparatus, and the cleaning liquid is guided to the spray nozzle 7 by the self-priming property of the spray nozzle 7. Can also be washed.

[0033]

According to the first aspect of the present invention, by controlling the opening and closing of a plurality of valves by a simple on / off signal, the combination of a plurality of orifices having different flow characteristics is changed to increase the flow rate of the fluid. An inexpensive flow control device that can be controlled in stages can be provided.

According to the second aspect of the present invention, only by inputting the required flow rate to the arithmetic and control unit, the arithmetic and control unit automatically controls the opening and closing of each valve to automatically set the combination of orifices. Can be changed.

According to the third aspect of the present invention, when the flow rate required by the spray nozzle is input to the arithmetic and control unit, a plurality of valves are controlled to open and close by signals from the arithmetic and control unit. By combining a plurality of orifices with different flow characteristics selected by operation, it is possible to provide a flow control device capable of controlling the flow rate of the fluid supplied from the fluid pressure source to the spray nozzle in multiple stages and at low cost.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a flow control device according to the present invention.

FIG. 2 is a graph showing a relationship between opening and closing of a valve and a flow rate in the flow rate control device.

[Explanation of symbols]

 Reference Signs List 1 Air pressure source as fluid pressure source 4 Orifice 5 Valve 7 Spray nozzle 8 Operation control unit

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Fujikawa 591-11, Kamihirose, Oaza, Sayama-shi, Saitama F-term in the Tamura FA system (reference) 4F035 AA04 BA05 BC06 5H307 AA20 BB02 CC12 DD12 EE04 EE36 ES02 GG03 HH01 HH06

Claims (3)

[Claims] 1. A combination of a plurality of orifices set to obtain different flow rates for the same fluid pressure and connected in parallel with each other, and orifices each connected in series to each of these orifices and selected by an opening operation. A flow control device comprising: a plurality of open / close-operated valves for controlling a flow rate of a fluid. 2. The flow control device according to claim 1, further comprising an arithmetic and control unit for controlling the opening and closing of each valve by inputting a required flow rate. 3. A fluid pressure source, a plurality of orifices set so as to obtain different flow rates with respect to a set pressure of the fluid pressure source, and connected in parallel with each other; and respectively connected in series to these orifices. A plurality of on-off operated valves, a spray nozzle to which a fluid of a flow rate determined by a combination of orifices selected by opening these valves is supplied, and each of the valves by inputting a flow rate required by the spray nozzle A flow control device, comprising: an arithmetic control unit that controls the opening and closing of the device.