JPH1066906A - Pressure regulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure regulator in which coating pressure supplied to, for example, a spray gun is kept constant and in which aluminum foils in metallic paint is prevented from being collapsed. SOLUTION: A paint supply path 2 is branched into first and second branches 2a, 2b in mid-way thereof. In the first and second branches 2a, 2b, first and second boosters 8a, 8b are arranged, and also an inflow switching valve 4 and an outflow switching valve 5 are arranged at the branching point of the fluid supply pass 2 and the confluence thereof, respectively. While the first booster 8a discharges paint at a constant pressure, the second booster 8b accumulates paint to be supplied, and this operation is alternately repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a pressure regulating device for adjusting a pressure of a paint supplied to a paint gun, for example.

[0002]

2. Description of the Related Art Conventionally, as a pressure regulator used in a painting process of an automobile, for example, an on-off valve device such as Japanese Utility Model Publication No. 2-25493 has been known. This on-off valve device is
As shown in FIG. 4, the valve body 51 is provided with a paint inflow hole 52, a paint outflow hole 53, and a circulation hole 54, while a valve rod 55 that is movable toward and out of the outflow hole 53 is provided to open and close the outflow hole 53. And a valve portion 5 provided at an intermediate portion of the valve rod 55.
The flow path leading to the circulation hole 54 can also be opened and closed by 5a. Further, at a position facing the inflow hole 52, a diaphragm 57 that operates according to the relationship between the air pressure supplied from the air supply hole 56 and the paint pressure is provided.
The inflow hole 52 is made openable and closable by a pressure adjusting valve 58 which moves forward and backward in conjunction with the pressure sensor 7.

In such an on-off valve device, when the paint is supplied to the coating gun communicating with the outflow hole 53, the air supply hole 56 is used.
The pressure regulating air is supplied from the opening to open the inflow hole 52, the valve rod 55 is retracted to open the outflow hole 53, and at the same time, the flow path on the circulation hole 54 side is closed by the valve portion 55a. Then, the paint regulated by the diaphragm 57 is sent from the outflow hole 53 toward the painting gun. When the coating is to be interrupted, the valve rod 55 is advanced and the outflow hole 53 is stopped.
And at the same time, the paint is guided to the circulation hole 54 by opening the valve portion 55a side and circulated. The circulation of the paint is important especially when the aluminum foil or the like in the paint tends to settle and harden when it stays, such as a metallic paint.

[0004]

However, in the case of the pressure regulating device as described above, there is a limit in keeping the pressure of the paint supplied to the coating gun constant. In such a case, when the opening and closing of the inflow hole 52 is repeated by the pressure regulating valve 58, the flow of the paint is repeatedly flowed and stopped on the upstream side, and the aluminum foil in the paint tends to be crushed. When the flow path between them becomes narrower, the tendency of the aluminum foil to be crushed further increases, and as a result, there is a problem that the coating color becomes dark. The black color change caused by the forward and backward movement of the pressure regulating valve 58 is as follows.
Since the aluminum foil is circulated so as not to settle and harden even when it is not painted, it becomes remarkable with time, and the color is different between the first time and the last time of the production rod even with the same color.

Therefore, there has been a demand for a pressure regulating device which can supply the paint to the coating gun at a constant pressure as much as possible, and which does not cause a black color change especially in the case of metallic paint containing aluminum foil.

[0006]

According to the present invention, in order to solve the above-mentioned problems, the present invention is characterized in that, in the first aspect, a branch point is connected to a supply portion of a fluid such as paint and is branched into first and second branch paths at a branch point on the upstream side. After that, the fluid supply path merging at the downstream merging point and the first and second fluid accumulating / discharging sections disposed in the first and second branch paths.
Discharge means, flow path switching means disposed at a junction and a junction of the fluid supply path, and control means for controlling each fluid accumulation / discharge means and flow path switching means, provided by the control means,
While the first fluid accumulating / discharging means ejects the fluid at a constant pressure, the second fluid accumulating / discharging means accumulates the supplied fluid, and controls so as to repeat the same alternately.

[0007] The fluid sent from the fluid supply unit is alternately sent to the first branch and the second branch by the flow path switching means at the branch point, and the sent fluid is stored in the fluid storage / discharge means on the corresponding side. When the fluid is discharged at a constant pressure by the fluid storage / discharge means on the other side while controlling the flow path switching means at the junction, the discharged fluid pressure can be kept constant.

In addition, since the fluid always circulates without staying in the fluid supply path, even in the case of metallic paint containing aluminum foil, for example, the problem that the aluminum foil is crushed is eliminated and the black color change can be suppressed.

According to the second aspect of the present invention, the switching between the discharge and accumulation of the fluid by each fluid accumulation / discharge means is performed on one side of the fluid accumulation / discharge means.
After a lapse of a predetermined time from the time when the discharging means starts discharging, the control is performed so that the fluid accumulation / discharge means on the other side performs fluid accumulation.

[0010] The predetermined time is a time sufficient to prevent pressure loss at the time of switching of the flow path switching means, and is, for example, about several seconds. By thus overlapping the discharge timings of the respective fluid accumulation / discharge means, pressure loss at the time of switching is prevented, which is more effective in preventing pulsation.

According to a third aspect of the present invention, the first and second fluid accumulating / discharging means are configured such that the piston is retracted by the supply of air pressure or the fluid pressure to accumulate fluid in the filling chamber, and the piston is supplied by the supply of air pressure. A pneumatic actuator that discharges fluid by moving forward. That is, accumulation of the fluid is performed by the retraction of the piston by the supply of the air pressure or by the action of the fluid pressure itself, and the discharge of the fluid is performed by the advance of the piston by the supply of the air pressure. , So that the fluid is discharged at a uniform air pressure by a constant air pressure. Also, by using a pneumatic actuator,
It becomes a simple configuration.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is an overall view showing a configuration example in which the present pressure adjusting device is applied to a coating device, and FIG.
FIG. 3 is a state diagram when the first and second boosters as the second fluid accumulation / discharge means rise, and FIG. 3 is a state diagram when the first and second boosters enter a circulation cycle.

The pressure adjusting device of the present invention is applied to a coating device for supplying a metallic paint containing aluminum foil to a coating gun, for example, as shown in FIG. A paint supply passage 2 connects the paint supply unit 1 and the paint gun G, and a pump 3 for feeding paint.

The paint supply path 2 is branched from a branch point in the middle into a first branch path 2a and a second branch path 2b, and merges at a downstream junction. An inflow switching valve 4 as switching means is provided, and an outflow switching valve 5 as flow switching means is also provided at the junction. Further, a paint switching valve 6 is provided in the paint supply path 2 further downstream.

The inflow switching valve 4 is provided with a first
An inflow switching valve 4a and a second inflow switching valve 4b are provided to switch between flowing the paint into the first branch 2a and flowing into the second branch 2a. It comprises a 1 outflow switching valve 5a and a 2nd outflow switching valve 5b, and switches between flowing out the paint in the first branch 2a and flowing out the paint in the second branch 2b. The coating switching valve 6 includes a circulation valve 6a and a coating valve 6b, and switches between circulating the coating through the circulation path 7 and guiding the coating to the coating gun G.

The first branch 2a and the second branch 2b are provided with a first booster 8a and a second booster 8b as fluid storage / discharge means, respectively. The first and second boosters 8a and 8b are controlled by control means (not shown) so as to repeat the accumulation and discharge of the paint, and the boosters 8a and 8b have the same configuration.

That is, each booster 8a, 8b includes a paint chamber 10, a cylinder 11, and a detector 12, and a rod 14 extending downward from a piston 13 provided in the cylinder 11 is coated with a paint. The paint chamber 10 is inserted into the cylinder, and the space inside the cylinder at one end of the paint chamber 10 is divided into an inflow hole 10a and an outflow hole 10b in the form of a flute.
0a and the outflow hole 10b communicate with each of the branch paths 2a and 2b. The cylinder section 11 is provided with a first port 11a and a second port 11b for introducing pressurized air, and the piston 13 is operated by the pressurized air. The second port 11b may be provided with a function of only exhausting air without introducing pressurized air, and when the rod 14 receives paint pressure, the piston 13 may be raised by the paint pressure.

When the piston 13 is raised with the paint flowing into each of the branch passages 2a and 2b, the paint chamber 10
The space inside the cylinder is filled with paint, and the piston 13 rises.
Is lowered, the paint in the in-cylinder space of the paint chamber 10 is discharged. Incidentally, even at the lower limit position of the piston 13, the inflow hole 10a and the outflow hole 10b can maintain the communication state.

A detection rod 15 extends upwardly above the piston 13, and a detection section 15 a provided at the tip of the detection rod 15 faces the inside of the detection section 12. An upper limit switch 16 and a lower limit switch 17 are provided in the detector 12. The upper and lower positions of the piston 13 are detected by the limit switches 16, 17 and the detector 15a.

Regarding the operation of the pressure regulator as described above,
A description will be given mainly of the movement of the first and second boosters with reference to FIGS. 2 and 3. First, when the apparatus is started, the inflow switching valve 4 is opened, the outflow switching valve 5 is closed, and pressurized air is introduced into the first and second boosters 8a and 8b on the second port 11b side. Then, the piston 13 is raised to fill the paint chamber 10 with paint (FIG. 2A).

The detection units 12 of both boosters 8a, 8b
When the upper limit position of the piston 13 is detected, the inflow switching valve 4 is closed, and among the outflow switching valves 5, the first outflow switching valve 5a is opened while the second outflow switching valve 5b is closed. As shown in (B), pressurized air is introduced from the first port 11a of the first booster 8a to start lowering the piston 13. When the piston 13 of the first booster 8a is lowered at a constant speed, the paint in the paint chamber 10 is fed at a uniform discharge pressure.

Next, as shown in FIG. 2 (C), at the same time when the detection unit 12 of the first booster 8a detects the lower limit position of the piston 13, the second outflow switching valve 5b is switched to the open state, and at the same time, The introduction of pressurized air from the first port 11a of the second booster 8b is started. For this reason, the piston 13 of the second booster 8b starts descending at a constant speed, and the paint in the paint chamber 10 starts to be fed under a uniform discharge pressure.

From this point, the first and second boosters 8a and 8b enter a circulating cycle in which charging and discharging are alternately repeated. That is, about one second after the start of the discharge of the paint by the second booster 8b, the first outflow switching valve 5a is closed, and at the same time, the first inflow switching valve 4a is opened, and the first booster 8a is closed. 2 ports 11
b, pressurized air is introduced, the piston 13 starts to rise, and the filling into the paint chamber 10 is started (FIG. 3).
(A)).

Then, while the discharge of the second booster 8b is performed, the filling of the first booster 8a is completed as shown in FIG. 3 (B). Next, as shown in FIG. 3C, the detection unit 12 of the second booster 8b detects the lower limit position of the piston 13 and at the same time, the first outflow switching valve 5a
Is switched to the open state, and at the same time, pressurized air is introduced from the first port 11a of the first booster 8a, and the paint in the paint chamber 10 starts to be fed under uniform discharge pressure.

About one second after the discharge of the paint by the first booster 8a is started, the second outflow switching valve 5b is closed, and at the same time, the second inflow switching valve 4b is opened. Pressurized air is introduced from the second port 11b, the piston 13 starts to rise, and the filling into the paint chamber 10 is started (FIG. 3 (D)).

Then, in a similar manner, FIGS.
The circulation cycle is repeated as (F) to (A). Also,
The coating switching valve 6 closes the circulation valve 6a to open the coating valve 6b when supplying coating material to the coating gun G, and closes the coating valve 6b to stop the coating when stopping coating. Open and circulate paint.

In the circulation of the paint, for example, the inflow switching valve 4 is opened, and the boosters 8a, 8
The piston 13 of b is set to the lower limit position, the first outflow switching valve 5a of the outflow switching valves 5 is opened, and the second outflow switching valve 5b is closed to circulate the paint.

In the above-described pressure regulator, the paint supplied to the coating gun G can be supplied at a uniform pressure by the uniform discharge by the boosters 8a and 8b, and the boosters 8a and 8b When switching
Since the discharge operations are overlapped for about one second, pressure drop during switching can be prevented, and pulsation can be prevented.

In addition, during coating and during circulation, the coating flows without stagnating in the coating supply path 2, and the aluminum foil is not crushed, so that black color change can be prevented. As described above, in the above embodiment, the boosters 8a and 8b may be raised not by pressurized air introduced from the second port 11b but by paint pressure.

[0030]

As described above, in the pressure regulating device of the present invention, the fluid supply passage is branched into the first and second branch passages, and the first and second fluid accumulation / discharge passages are formed in the first and second branch passages. Means is provided, and a flow path switching means is provided at a junction and a junction of the fluid supply path, and the control means controls the first fluid accumulation / discharge means to discharge the fluid at a constant pressure while the second fluid accumulation / discharge means discharges the fluid at a constant pressure. The fluid storage / discharge means stores the supplied fluid and controls the fluid to alternately repeat, so that the pressure of the discharged fluid can be always kept constant. Further, since the fluid can be constantly circulated, for example, even when the fluid is a metallic paint containing an aluminum foil, there is no problem that the aluminum foil is crushed, and black change can be suppressed. In addition, the timing of fluid discharge by each fluid accumulation / discharge means is overlapped, and after a predetermined time has elapsed from the time when the fluid accumulation / discharge means on one side starts discharging, the accumulation of fluid by the fluid accumulation / discharge means on the other side is performed. Is performed, pressure loss at the time of switching can be prevented, which is more effective in preventing pulsation.

[Brief description of the drawings]

FIG. 1 is an overall view showing a configuration example in which the present pressure adjusting device is applied to a coating device.

FIG. 2 shows first and second fluid accumulation / discharge means as first and second fluid accumulation / discharge means;
State diagram when the second booster rises

FIG. 3 is a state diagram when a circulation cycle of the first and second boosters is entered.

FIG. 4 is a conventional diagram of a pressure adjusting device.

[Explanation of symbols]

1: paint supply section, 2: paint supply path, 2a: first branch path,
2b: second branch, 4: inflow switching valve, 5: outflow switching valve, 8a: first booster, 8b: second booster, 13: piston.

Claims (3)

[Claims] A first fluid supply path connected to a supply portion of a fluid such as paint and branching at an upstream branch point into first and second branch paths, and then joining at a downstream junction point; First and second fluid accumulating / discharging means disposed in the second branch, flow switching means disposed at a junction of the fluid supply path and a junction, and each fluid accumulating / discharging means And control means for controlling the flow path switching means. The control means controls the fluid supplied by the second fluid accumulation / discharge means while the first fluid accumulation / discharge means discharges the fluid at a constant pressure. A pressure regulating device, wherein the pressure is accumulated and controlled so as to be alternately repeated. 2. The pressure regulator according to claim 1, wherein the switching between the discharge and accumulation of the fluid by each of the fluid accumulation / discharge means is performed for a predetermined time from the time when the fluid accumulation / discharge means on one side starts ejection. After the lapse of time, the pressure control device is controlled so that the fluid is accumulated by the fluid accumulation / discharge means on the other side. 3. The pressure regulating device according to claim 1, wherein the first and second fluid accumulating / discharging means are configured such that a piston is retreated by air pressure supply or fluid pressure to move the piston into a filling chamber. A pressure regulator, wherein the pressure regulator is a pneumatic actuator that accumulates a fluid and causes a piston to advance by a supply of air pressure to discharge the fluid.