JP3259075B2 - Intermediate storage tank for coating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate storage tank provided mainly between a paint supply source and a coating gun in a coating apparatus for electrostatically coating a conductive paint.

[0002]

2. Description of the Related Art When a conductive paint is electrostatically applied, the insulation resistance of a paint supply system is reduced, and it becomes difficult to apply a high voltage to a paint gun. As an apparatus for solving such a problem, an intermediate storage tank is provided between a paint supply source and a coating gun according to JP-A-63-310671, and an intermediate storage tank is provided via a supply path from a grounded paint supply source. After supplying the paint to the storage tank, at least a part of the supply path is emptied to insulate the intermediate storage tank from the ground potential, and in this state, the paint is supplied from the intermediate storage tank to the coating gun via the delivery path. Things are known. And in this thing, the intermediate storage tank is composed of a cylinder with a built-in piston driven forward and backward,
One of the chambers in the cylinder partitioned by the piston is used as a paint chamber, and the paint is supplied to the paint chamber via a liquid supply path formed in a piston rod and a piston and connected to a supply path,
In the forward movement of the piston to the paint chamber side, paint is delivered through a delivery path connected to the end wall of the paint chamber, and further,
When the paint is switched, a cleaning liquid is injected into the paint chamber from the liquid supply path to clean the paint chamber. Further, in this apparatus, a liquid supply passage formed in the piston is opened to the paint-side end surface of the piston so as to be inclined outward, and the cleaning liquid is discharged with a velocity component directed toward the inner wall surface of the cylinder.

[0003]

As described above, the cleaning liquid is discharged with a velocity component directed toward the inner wall surface of the cylinder.
In order to enhance the cleaning effect of paint remaining on the inner wall surface of the cylinder, the liquid supply passage is opened at the end face of the piston. It is difficult for the cleaning liquid to enter the gap formed between the surface and the inner wall surface of the cylinder, so that the paint tends to remain in this portion. Further, the paint tends to remain on the end face of the piston, and it takes a long time for cleaning. SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an intermediate storage tank capable of reliably cleaning a paint chamber in a cylinder including a piston in a short time.

[0004]

In order to achieve the above object,
The present invention is an intermediate storage tank provided between a paint supply source and a coating gun, which is constituted by a cylinder having a built-in piston driven forward and backward, and supplies one chamber in a cylinder partitioned by the piston to a paint supply tank. In a paint chamber connected to a supply path connected to a source and a delivery path connected to a coating gun, a liquid supply path for a cleaning liquid is formed in a piston, and the liquid supply path is formed in a piston for a seal member. And a cleaning liquid discharge port for discharging a cleaning liquid toward an end surface of the piston toward the paint chamber is provided in an end wall of the paint chamber.

[0005]

The piston end face is cleanly cleaned in a short time by the cleaning liquid discharged from the cleaning liquid discharge port toward the piston end face, and the liquid supply path is opened on the outer peripheral surface of the land portion of the mounting groove of the seal member. The cleaning liquid is injected into the paint chamber through the gap between the inner wall surface and the land, and the inner wall surface of the cylinder including the paint remaining in the gap is also cleanly cleaned. In addition, if the piston is rotatable, even if the cleaning liquid is not discharged uniformly from the outer peripheral surface of the land portion to the entire circumference thereof, the inner wall surface of the cylinder can be uniformly washed over the entire circumference by the rotation of the piston. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a paint switching valve, 2 denotes a coating gun, an intermediate storage tank 3 is provided between the coating switching valve 1 and the coating gun 2, and a supply connected to the paint switching valve 1. The paint is supplied to the intermediate storage tank 3 via the path 4, and the paint is supplied from the storage tank 3 to the coating gun 2 via the delivery path 5.

The paint switching valve 1 includes a plurality of paint valves 1a for supplying paint from various paint tanks (not shown), a cleaning valve 1b, and an air valve 1c. Various paints are supplied via the cleaning valve 1b, and when the paints are switched, the cleaning liquid is supplied through the cleaning valve 1b and the air is supplied through the air valve 1c to clean the supply path 4.

The supply path 4 includes first to third
Are divided into four passages 4a, 4b, 4c, and 4d by the three switching valves 41, 42, and 43. The passages are all connected to supply the paint to the intermediate storage tank 3. Is connected to the delivery path 5 by the third switching valve 43 so as to prepare for the delivery of the paint to the coating gun 2. If the paint is conductive, the intermediate storage tank is used. after the paint supply to 3 by the second switching valve 42 to its downstream end with connecting an upstream end of the passage portion 4b to the cleaning unit valve 6 by the first switching valve 41 to switch connection to the first drainage path ₇₁ After flowing the cleaning liquid from the cleaning valve 6a of the unit valve 6 to the passage portion 4b, air is flown from the air valve 6b of the unit valve 6 so that the paint tank at the ground potential and the coating gun 2 applied to the high voltage are connected. Electrical disconnect between The securing at the passage portion 4b.

The intermediate storage tank 3 comprises a vertically long cylinder 32 having a built-in piston 31 which is vertically moved via a rod 31a by a driving source 8 comprising an air cylinder. The passage section 4d, which is a common passage for the path 4 and the delivery path 5, is connected, and the lower chamber of the piston 31 in the cylinder 32 is configured as a paint chamber 33. When the paint is supplied, the drive source 8 is set in a free state. The piston 31 is pushed up with the paint flowing into the paint chamber 33, and the drive source 8 pushes down the piston 31 at the time of feeding the paint.

A cleaning liquid supply path 9 is connected to the upper end of the cylinder 32, and a chamber above the piston 31 in the cylinder 32 is formed as a cleaning liquid chamber 34. The paint remaining on the inner wall surface of the cylinder 32 is removed by air. To prevent solidification by exposure to water. A reserve tank 91 is provided in the supply path 9 of the cleaning liquid, and a switching valve 92 is provided between the tank 91 and the cleaning liquid chamber 34. The switching valve 92 allows the reserve tank 91 and the cleaning liquid chamber 34 to communicate with each other. And the cleaning liquid chamber 34 is moved to the second
It was freely switched between a state of connection to the liquid discharge path 7 _2. Then, the liquid supply valve 9 on the upstream side is provided in the reserve tank 91.
When a required amount of the cleaning liquid is supplied through 3 and the supply and the supply of the paint to the paint chamber 33 are repeated with the same paint,
The reservoir tank 91 and the cleaning liquid chamber 34 are communicated with each other so that the cleaning liquid reciprocates between them.

As shown in FIG. 2, the piston 31 has
A seal member 31 b formed by laminating a plurality of V packings is mounted.
A liquid supply passage 31c is formed to communicate the liquid supply 4 with the lower paint chamber 33, and a check valve 35 for preventing the flow from the paint chamber 33 to the cleaning liquid chamber 34 is provided in the liquid supply passage 31c. And
When the paint is switched, when the communication between the reserve tank 91 and the cleaning liquid chamber 34 is cut off after the previous paint is delivered and the drive source 8 pulls up the piston 31, the check valve 35 is opened and the cleaning liquid in the cleaning liquid chamber 34 is supplied. The liquid was injected into the paint chamber 33 through the passage 31c.

The liquid supply passage 31c has a land 31d at the lower end of a mounting groove of a seal member 31b formed in the piston 31.
The annular groove 31e is formed on the outer peripheral surface of the land portion 31d.
e so that the liquid supply path 3 communicates with the e.
A plurality of 1c was formed, and the cleaning liquid was discharged almost uniformly over the entire circumference of the land 31d. According to this,
The cleaning liquid is injected into the paint chamber 33 through the gap between the outer peripheral surface of the land portion 31d and the inner wall surface of the cylinder 32, and the inner wall surface of the cylinder including the paint remaining in this gap is cleaned in a short time. You. In addition, although each discharge hole connected to each liquid supply path 31c may be opened on the outer peripheral surface of the land portion 31d, in this case, the piston 31 is made rotatable, and the discharge amount of the cleaning liquid is adjusted by turning the piston 31. It is desirable to equalize in the circumferential direction. In order to rotate the piston 31, for example, a screw rod inserted into a fixed nut may be connected to the piston rod 31a, and the screw rod may be rotated by a drive shaft such as a motor.

A plurality of cleaning liquid discharge ports 12 for supplying a cleaning liquid from a second supply path 10 of the cleaning liquid via a liquid supply valve 11 are provided at an end wall portion of the paint chamber 33, that is, at a lower end of the cylinder 32. ing. When the paint is switched, the piston 31 is pulled up as described above, and the land 3 at the lower end is pulled up.
When the cleaning liquid is discharged from 1d to clean the inner wall surface of the cylinder 32, the cleaning liquid is discharged from the cleaning liquid discharge port 12 toward the lower end surface of the piston 31, so that the lower end surface of the piston 31 can be efficiently cleaned. . The cleaning liquid in the paint chamber 33 is discharged through the passage 4d by pushing down the piston 31, and then the next paint is supplied to the paint chamber 33, and the switching of the paint is completed.

In the above embodiment, the chamber opposite to the paint chamber 33 in the cylinder 32 is defined as a cleaning liquid chamber 34, and the cleaning liquid in the cleaning liquid chamber 34 is supplied to the paint chamber 33 via the liquid supply passage 31c of the piston 31. Although it was made to inject, the cleaning liquid was injected into the coating chamber by connecting the liquid supply path to the cleaning liquid supply path through a passage formed in the piston rod, making the chamber opposite to the coating chamber empty. In this case, the supply path of the cleaning liquid and the supply path of the paint may be selectively connected to the passage of the piston rod, and the paint may be supplied to the paint chamber via the supply path of the piston.

[0015]

As is apparent from the above description, according to the present invention, the paint remaining on the piston between the land of the seal mounting groove and the inner wall surface of the cylinder and the paint remaining on the end face of the piston are reduced. These paints can be efficiently washed away by directly applying the cleaning liquid, and the paint chamber including the piston can be reliably washed in a short time.

[Brief description of the drawings]

FIG. 1 is a cutaway side view of an example of the apparatus of the present invention.

FIG. 2 is an enlarged view of the main part.

[Explanation of symbols]

2 Coating gun 3 Intermediate storage tank 31 Piston 31b Seal member 31c Liquid supply path 31d
Land 32 Cylinder 33 Paint room 4
Paint supply route 5 Paint delivery route 12 Cleaning liquid discharge port

Claims (2)

(57) [Claims] An intermediate storage tank provided between a paint supply source and a coating gun, comprising a cylinder having a built-in piston which is driven forward and backward, wherein one of the chambers in the cylinder partitioned by the piston is coated with a paint. In the paint chamber connected to the supply path connected to the supply source and the delivery path connected to the coating gun, a liquid supply path for the cleaning liquid is formed in the piston,
The liquid supply passage is opened on the outer peripheral surface of the land on the paint chamber side of the mounting groove for the seal member formed in the piston, and the cleaning liquid is discharged toward the end wall of the piston on the paint chamber side at the end wall of the paint chamber. An intermediate storage tank of a coating apparatus, wherein a cleaning liquid discharge port is provided. 2. The intermediate storage tank according to claim 1, wherein said piston is rotatable.