JPS63111963A - Coating agent feeder - Google Patents

Abstract

PURPOSE:To supply a coating agent at a fixed flow rate by using a rotary pump such as a gear pump, etc., as the metering pump, and regulating the pump when the variations in the pressure difference between the suction side and the delivery side of the pump are caused. CONSTITUTION:The coating agent supplied from a coating agent supply source 1 at a specified pressure is supplied to an applicator 4 at a specified pressure through a pressure regulator 5. Besides, a rotary pump 7 to be driven at preset r.p.m. is provided between the pressure regulator 5 and the applicator 4. Furthermore, the coating agent supply pressure on the delivery side of the rotary pump 7 is detected by a pressure control unit 9, and the set pressure of the pressure regulator 5 is adjusted so that the pressure difference between the suction side and the delivery side of the rotary pump 7 is controlled to a specified value. As a result, the flow rate of the coating agent to be supplied can be kept constant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coating agent supply device that maintains and supplies a coating agent at a predetermined flow rate to a coating machine such as an electrostatic coating machine or an air spray gun.

[Prior art and its problems]

Painting machines such as air spray guns are connected to a paint circulation system and are designed to supply paint at a predetermined pressure.
Since the supply pressure from the paint circulation system changes depending on the level of the paint in the paint tank and the operating conditions of other coating machines connected to the paint circulation system, the supply pressure from the paint circulation system is usually The supply pressure of the paint is lowered to a predetermined set pressure via a pressure regulator such as a paint regulator, and is maintained at a constant level before being supplied to the coating machine.

However, when strict flow rate control is required, for example when supplying a main component and a curing agent for a two-component paint, strictly speaking, the flow rate cannot be maintained constant using the paint regulator alone.

Therefore, in order to maintain a constant supply amount of paint, a rotary pump such as a gear pump is interposed as a metering pump between the paint circulation system and the coating machine, and the rotary pump is rotated at a preset rotation speed. We decided to supply paint at a constant flow rate to the paint sprayer by driving it.

However, in this case, if a pressure difference occurs between the suction port side and the discharge port side of the rotary pump, internal leakage will occur in the rotary pump, and if the pressure on the discharge port side increases, the paint will flow backwards. On the other hand, the pressure on the discharge port side decreases and the pressure on the suction port side becomes relatively high (this causes more paint to be fed than necessary, so if the pressure difference between the suction port and the discharge port changes, the paint There was a problem that it was not possible to maintain a constant flow rate.

[Purpose of the invention]

Therefore, the present invention uses a rotary pump such as a gear pump as a metering pump, and adjusts the pressure difference when it occurs between the suction port and the discharge port of the pump to control the supply flow rate of the coating material. It is an object of the present invention to provide a coating agent supply device that can be maintained constant.

[Structure of the invention]

In order to achieve this object, the present invention provides a coating agent which is adapted to supply a coating agent fed at a predetermined pressure from a coating agent supply source to a coating machine at a predetermined set pressure via a pressure steel moderator. In the agent supply device, a rotary pump driven at a predetermined rotation speed is interposed between the pressure regulator and the coating machine, and the coating agent feeding pressure on the discharge port side of the rotary pump is detected. The rotary pump is characterized in that a pressure control device is provided to adjust the set pressure of the pressure regulator so that the pressure difference between the suction port side and the discharge port side of the rotary pump becomes a predetermined value.

[Action of the invention]

According to the present invention, since the coating agent fed from the coating agent supply source is supplied to the applicator via the rotary pump driven at a predetermined rotation speed, the coating agent fed from the coating agent supply source is Even if there is some variation in the supply pressure, a substantially constant flow rate of the coating agent is discharged from the rotary pump, and the flow rate of the coating agent supplied to the coating machine is maintained substantially constant.

Further, a pressure sensor detects the coating agent feeding pressure on the discharge port side of the rotary pump, and a pressure control device adjusts the set pressure of the pressure regulator according to the output of the pressure sensor. Since the pressure difference between the rotary pump and the suction side is adjusted to a predetermined value, it is possible to maintain a constant supply flow rate by preventing flow fluctuations due to internal leakage of the rotary pump caused by fluctuations in pressure difference. .

In addition, a pressure sensor detects the coating material feeding pressure on the discharge port side of the rotary pump, and a pressure regulator is set so that the pressure difference between the discharge side and the suction side of the rotary pump becomes a predetermined value according to the output of the pressure sensor. Since a pressure control device is installed to adjust the set pressure of The supply flow rate of the agent can be maintained constant.

[Example I]

Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

The figure is a flow sheet showing an example of a coating agent supply device according to the present invention.

In the figure, reference numeral 1 denotes a paint circulation system (coating material supply source) that circulates and supplies the paint in a paint tank 2 at a predetermined pressure using, for example, a pump 3, and a spray gun (painting machine) 4 is connected to the paint circulation system 1. A gear pump (rotary pump) 7 as a metering pump driven by a motor 6 is interposed between the atomizer 4 and the paint regulator 5 and connected via a regulator 5 .

Reference numeral 8 denotes a drive control device that controls the rotation speed of the motor 6 that drives the gear pump 7, and by setting the paint supply flow rate in the control device 8, the motor is controlled to rotate at a predetermined rotation speed according to the supply flow rate. 6, so that the paint supplied from the paint circulation system 1 at a predetermined pressure can be discharged at a desired flow rate by means of a gear pump 7.

9 is a setting of the paint regulator 5 so that when a pressure difference fluctuates between the suction lower A side and the discharge lower B side of the gear pump 7, the pressure difference becomes a predetermined value (for example, O). It is a pressure regulating device for adjusting pressure, and a pressure sensor 10 for detecting the paint supply pressure at the discharge lower B of the gear pump 7 is connected to its input side, and a gear pump from the paint circulation system 1 is connected to its output side. A paint regulator 5 is connected to adjust the feeding pressure of the paint fed to the paint regulator 7.
A control signal C for adjusting the set pressure of the paint regulator 5 is output in accordance with the output signal of the pressure sensor 10.

1) is a piston valve linked to a trigger (not shown) of the spray gun 4, which supplies paint from the gear pump 7 to the spray gun 4 when the trigger is pulled; When not in use, the paint discharged from the gear pump 7 is returned to the paint tank 2 of the paint circulation system 1.

The above is an example of the configuration of the present invention, and its operation will be explained next.

First, the pump 3 of the paint circulation system 1 is started to pump paint at a predetermined pressure (for example, 3 kg/cd), and the initial setting pressure of the paint regulator 5 (for example, 1 kg/aa) is input to the pressure control device 9. .

When the gear pump 7 is driven by setting the desired paint supply amount in the drive control device 8, the gear pump 7 is driven at a predetermined rotation speed according to the paint supply amount, and the paint is pumped from the paint circulation system 1 at a rate of 3 kg/cd. The applied paint is reduced in pressure to 1 kg/c1) by the paint regulator 5, and then discharged from the gear pump 7 at a desired flow rate.

At this time, since the trigger of the spray gun 4 has not yet been pulled, the paint discharged from the gear pump 7 is being returned to the paint circulation system 1 via the piston valve 1).

Here, when the trigger of the spray gun 4 is pulled in order to paint an object to be painted (not shown), the piston valve 1) is switched and paint is supplied to the spray gun 4 at a constant flow rate.

When the feeding pressure on the discharge lower B side of the gear pump 7 changes due to the usage condition of the spray gun 4, for example, the position (height) of the spray gun 4, the degree of bending of the paint hose, etc., the change in pressure Detected by sensor 10.

Now, if the feed pressure on the discharge lower B side increases from 1 kg/d to 1.1 kg/aJ, the pressure sensor 10 detects this, and the pressure control device 9 outputs the control signal C. The set pressure of paint regulator 5 is 1.0 kg/
cal to 1.1 kg/cJ.

Therefore, the paint pumped from the paint circulation system 1 at a rate of 3 kg/cd is changed to +r/cd by the paint regulator 5 at 1.1 kg/cd.
Since the pressure on the suction lower A side and the discharge lower B side of the pump 7 becomes equal, the gear pump 7 can send paint at a constant flow rate without causing backflow due to internal leakage. can be provided.

Conversely, when the feed pressure on the discharge lower B side decreases from 1.1 kg/- to 0.9 kg/aa, the pressure sensor 10 detects this, and the pressure control device 9 outputs the control signal C. The set pressure of paint regulator 5 is 1.1 kg/cf
ll to 0,9 kr/crl.

Therefore, the paint, which has been fed under a reduced pressure of 1.1 kg/-, is further reduced in pressure to 0.9 kg/cd and fed to the gear pump 7, so that the pressure on the suction lower A side is reduced to the discharge lower B. The pressure is lowered to the side pressure, and the flow rate will not exceed the set flow rate due to internal leakage.

In this way, even if the pressure on the discharge lower B side of the gear pump 7 changes, the pressure sensor 10 detects this and adjusts the set pressure of the paint regulator 5, so that a balanced state of pressure can be maintained. As a result, no internal leakage occurs in the gear pump 7, and the paint supply flow rate is maintained constant.

[Example ■]

FIG. 2 is a flow sheet showing the main part of another embodiment of the present invention.

Note that parts that overlap with those in FIG. 1 are given the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, pressure sensors IOA and IOB are disposed on both the suction lower A and discharge lower B sides of the gear pump 7, and the pressure control device 9 controls the pressure difference detected by the pressure sensors IOA and IOB. A predetermined value (for example, 0.
2kg/cnl) Outputs a control signal C to adjust the set pressure of the paint regulator 5 so that Q is maintained.

That is, a closed loop is formed in which the pressure adjusted by the paint regulator 5 is confirmed by the pressure sensor IOA and fed back, and the pressure difference between the suction lower A side and the discharge lower B side of the gear pump 7 is maintained at a predetermined value. being done.

As described above, according to this embodiment, the paint feeding pressure not only on the discharge lower B side of the gear pump 7 but also on the suction lower A side is measured, so that more reliable pressure control can be performed.

[Example ■]

FIG. 3 is a flow sheet showing the main part of yet another embodiment. Note that parts that overlap with those in FIGS. 1 and 2 are given the same reference numerals, and detailed explanations are omitted.

In this embodiment, a gear pump 13 driven by an electric motor 12 is used instead of the paint regulator 5 as a pressure regulator, and a pressure difference is created between the suction lower A side and the discharge lower B side of the gear pump 7 as a metering pump. If this occurs,
A control signal C for increasing or decreasing the rotation speed of the electric motor 12 is output from the pressure control device 9 to the inverter 14, and the discharge pressure (set pressure) of the gear pump 13 is adjusted.

And the suction lower A of the gear pump 7 as a metering pump.
When pressure fluctuation occurs between the side and the discharge lower B side, this is detected by pressure sensors IOA and IOB, and when the pressure on the suction lower A side becomes relatively higher than the pressure on the discharge lower B side, In this case, a control signal C is outputted from the pressure control device 9 to lower the rotation speed of the motor 12, the discharge amount of the gear pump 13 as a pressure regulator is decreased, the pressure on the suction lower A side of the gear pump 7 is lowered, and the discharge is reduced. It becomes equal to the pressure on the lower B side.

Conversely, when the pressure on the suction lower A side becomes relatively lower than the pressure on the discharge lower B side, a control signal C is sent from the pressure control device 9 to the inverter 14 to increase the rotation speed of the motor 12. Gear pump 1 as output and pressure regulator
Gear pump 7 can be used as a metering pump by increasing the discharge amount of 3.
The pressure on the suction lower A side increases and becomes equal to the pressure on the discharge lower B side.

In this way, according to this embodiment, the rotation speed of the gear pump 13 as a pressure regulator is controlled so that the pressures on the suction lower A side and the discharge lower B side of the gear pump 7 as a metering pump are equalized. Therefore, internal leakage due to the pressure difference between the suction lower A side and the discharge lower B side does not occur in the gear pump 7 as a metering pump, and therefore the discharge amount of the gear pump 7 as a metering pump is always constant. It will be maintained.

Note that in the above embodiment, only the case where the gear pump 7 is used as the rotary pump has been described, but the present invention is not limited to this, and any rotary pump such as a vane pump or a screw pump can be used.

Furthermore, the pressure regulator is not limited to the paint regulator 5 and the gear pump 13, but any other regulating valve or continuous discharge pump can be used as desired.

Furthermore, in the examples, only the case where paint was used as the coating agent was explained, but the base coating oil, dye,
It can be applied as a supplying device for any coating agent such as ink, and when used as a supplying device for a main component and a curing agent for a two-component mixed paint, the main component supplying device and curing agent supplying device that can be used throughout the present invention are applicable. They may be arranged in parallel, and the supplied main agent and curing agent may be mixed in a mixer and then supplied to the spray gun 4.

〔Effect of the invention〕

As described above, according to the present invention, the coating agent fed from the coating agent supply source is supplied to the coating machine via the rotary pump driven at a predetermined rotation speed, so that the coating agent can be coated easily. Even if there is some variation in the supply pressure of the coating agent, a constant flow rate of the coating agent is discharged from the rotary pump, and the flow rate of the coating agent supplied to the coating machine can be maintained constant.・Even if there is a pressure difference between the pump's discharge port and suction port, the pressure sensor detects it and adjusts the set pressure of the pressure regulator to maintain the pressure difference between the discharge port and suction port. Since the flow rate is maintained at the same value, it has the excellent effect of being able to eliminate fluctuations in flow rate due to internal leakage of the rotary pump.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an example of the coating agent supply device according to the present invention, FIG. 2 is a flow sheet showing another embodiment, and FIG. 3 is a flow sheet showing still another embodiment. Explanation of symbols 1-Paint circulation system (coating agent supply source), 2-Paint tank,
3...-pump, 4--spray gun (applicator), 5
- Paint regulator (pressure regulator), 7 - Gear pump (rotary pump), 8 - Drive control device, 9 - Pressure regulator, 10.10A, 10B - Pressure sensor, 12 - Electric motor, 13 - Gear pump (pressure regulator) vessel).

Claims (4)

[Claims] (1) In a coating agent supply device configured to supply a coating agent at a predetermined pressure from a coating agent supply source to a coating machine at a predetermined set pressure via a pressure regulator, the pressure regulator and the coating agent A rotary pump driven at a predetermined rotation speed is interposed between the rotary pump and the rotary pump, and detects the coating agent feeding pressure on the discharge port side of the rotary pump and connects the suction port side and discharge side of the rotary pump. A coating agent supply device characterized in that a pressure control device is provided to adjust the set pressure of the pressure regulator so that the pressure difference on the outlet side becomes a predetermined value. (2) The pressure control device detects a pressure difference between the discharge side and the suction side of the rotary pump, and adjusts the set pressure of the pressure regulator according to the pressure difference. The coating agent supply device according to item 1. (3) The coating agent supply device according to claim 1, wherein the pressure regulator is a regulator. (4) The coating agent supply device according to claim 1, wherein the rotary pump is a gear pump.