JPH0810384Y2 - Return valve with leakage small hole - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is used in a simple airless spray paint applicator, has a high pressure inlet and a low pressure outlet communicating with a valve chamber, and opens and closes the valve. It relates to a rod-type return valve.

(Prior Art) Conventionally, a return valve is of a type that flows in from a lower high pressure port and escapes from a horizontal low pressure port, and the amount of the relief is adjusted by the opening / closing amount of a valve rod provided inside. there were.

In addition, the publication of August 5, 1977, Kosuke Shobo published by Junsuke Ishiwatari and 3 others, the latest industrial coating technology, pp. 584 to 585, see Fig. The coating circulation device used is described, and in particular, a pressure difference occurs between the upstream side and the downstream side of the monoflow joint.

(Problem to be Solved by the Invention) In the conventional return valve, the high pressure side can be released or returned from the low pressure side by opening and closing the valve rod. However,
In order to reduce the pressure on the high pressure side to a certain level or maintain it at a constant pressure, it is difficult to open the valve stem, and it takes time to adjust the opening of the valve stem, and it is a high pressure especially in a coating machine for airless spray. Therefore, delicate adjustment was required.

(Means for Solving the Problem) Used in a simple airless spray paint applicator, at least the lower high-pressure inlet (14) communicating with the valve chamber (11a) in the return valve body (11) and the side Side low pressure discharge port (15) is bored, and in the return valve (9) equipped with a valve rod (13) that moves up and down in the valve chamber (11a), the valve rod (13) has a , A small hole (13a) extending vertically from the lower end and a small hole (13a) penetrating from the side
A lateral hole (13b) having a larger diameter than the small hole (13a) is also provided.

(Operation) First, paint is put in the paint tank (1), and then the handle (17) of the return valve (9) is turned to open the valve rod (13). Next, when the airless pump (4) is operated, the paint is discharged to the high pressure section pipe (6) and the accumulator (5) through the suction strainer (2) and the suction pipe (3), and at the same time the valve is opened. After passing through the return valve (9) side, enter the return pipe (10) and return to the paint tank (1). After turning the valve for a while in this state to reach a steady state, turn the handle (17) of the return valve (9) to close the valve rod (13), and the pressure in the accumulator (5) and the high pressure section pipe (6) will be Ascending, paint pressure is also applied to the spray gun (7). Here, when the spray gun (7) is opened, the paint is sprayed and applied in a fan shape from the nozzle (8). In this case, while the spray gun (7) is closed and the injection is stopped, the pressure in the high-pressure pipe (6) rises, but the paint is applied to the small holes provided in the valve rod (13) of the return valve (9). A small amount is always leaked to the return pipe (10) through the (13a) and the lateral hole (13b), and the pressure increase is appropriately suppressed. That is, the difference between the pressure at the start of spraying and the pressure during spraying is small, and during spraying, the uneven coating is eliminated and the recoil generated in the spray gun (7) is reduced.

Also, the lateral hole (13b) formed in the valve rod (13) is a small hole (13a).
By making it several times larger than the caliber and making it orthogonal, the paint injection pressure that is injected at high pressure from the small hole (13a) is received by the orthogonal horizontal hole (13b), and the speed of exiting from the horizontal hole (13b) is greatly reduced. Therefore, the surrounding components touched by paint other than the valve stem (13), that is, the retainer fitting (16),
There is little influence on the material of the return valve body (11), it does not require wear resistance for these materials, and general metal materials can be used sufficiently. Only the valve rod (13) can be made of highly durable material. It will be possible.

(Example) An example of the present invention will be described with reference to the drawings.

1 is a block diagram of a simple airless spray paint applicator using the return valve of the present invention, FIG. 2 is a side sectional view of the return valve of the present invention, and FIG. 3 is a sectional view of a valve stem of the present invention. Is.

In FIG. 1, (1) is a paint tank, (2) is a suction strainer placed in the paint tank (1),
(3) is a suction pipe connected to the suction strainer (2),
(4) is an airless pump connected to one of the suction pipes (3), (5) is an accumulator, (6) is a high pressure pipe connected to the discharge side of the airless pump (4), (7) is a high pressure pipe A spray gun connected to (6), (8) a nozzle of the spray gun (7), (9) a return valve of the present invention, (10) a return pipe, and a return valve (9).
Except for this, the description is omitted because it is already known.

Next, the return valve (9) will be described in detail with reference to FIG. 2. The return valve (9) is composed of a valve chamber (11a).
A return valve body (11) having a lower high-pressure inlet (14) and a lateral low-pressure outlet (15) communicating with the cap, and a cap nut (12) screwed onto the return valve body (11).
A valve rod (13) for opening and closing the valve chamber (11a) in the return valve body (11), a holding metal fitting (16) for holding the valve rod (13) at the upper part, and a holding metal fitting (16). A handle (17) provided on the upper part and a valve seat (18) provided directly below the valve rod (13)
And the cap nut (12) at the top of the return valve body (11)
Since it is composed of a packing (19) provided between the valve rod and the valve rod, and is basically the same as the known one except these valve rods (13), the valve rod (13) will be described in detail with reference to FIG. To describe,
The valve rod (13) is provided with a small hole (13a) in the shape of a blind, which is bored vertically from the center of its lower end, and a horizontal hole (13b) which penetrates from the side and communicates with the small hole (13a) in an orthogonal manner. There is. That is,
The valve rod (13) is formed with a flow path that enters from the lower end and flows out to both sides, and the lateral hole (13b) has a diameter several times larger than that of the small hole (13a).

Further, since the valve rod (13) is severely worn, a material having high wear resistance is used. For example, conventionally used tungsten carbide is preferable. Furthermore, the diameter of the small hole (13a) may be set to a size that provides an optimum leak amount for the characteristics of the airless pump (4) used.

(Effects of the Invention) The present invention thus configured has the following effects.

By forming the small hole (13a) and the lateral hole (13b) in the valve rod (13), the valve rod (13) is in contact with the valve seat (18) even from the initially opened state, that is, the valve rod ( By closing 13), the optimum leak amount (relief amount) for the characteristics of the airless pump (4) to be used becomes possible, and it is possible to leak due to the opening degree of the valve stem (13) as in the past. In comparison, it does not require fine adjustment of the opening of the valve stem (13) due to its personality.

Also, the horizontal hole (13b) is orthogonal to the small hole (13a) and has a diameter several times larger, so that the high pressure flow flowing in from the small hole (13a) hits the horizontal hole (13b) and is decelerated and decompressed for a long time. Return valve body (1
The influence of abrasion and the like on 1) and the holding metal fitting (16) is extremely reduced, and the durability of the return valve (9) itself is improved as compared with the conventional use in which the valve rod (13) is opened.

[Brief description of drawings]

FIG. 1 is a block diagram of a simple airless spray type paint applicator using the return valve of the present invention, FIG. 2 is a side sectional view of the return valve of the present invention, and FIG. 3 is a sectional view of a valve rod. . (9) …… Return valve, (11) …… Return valve body (11a) …… Valve chamber, (13) …… Valve rod (13a) …… Small hole, (13b) …… Horizontal hole (14) …… High pressure inlet, (15) …… Low pressure outlet

Claims (1)

[Scope of utility model registration request] 1. A low-pressure high-pressure inlet (14) and a low-pressure discharge outlet on the side, which are used in a simple airless spray coating machine and communicate with at least a valve chamber (11a) in a return valve body (11). (15) and a return valve (9) having a valve rod (13) that moves vertically in the valve chamber (11a), the valve rod (13) has a vertical direction from its lower end. The small hole (13a) facing in the direction, and the small hole (1a
A return valve having a leakage small hole, characterized in that a lateral hole (13b) communicating with the small hole (13a) and having a larger diameter than the small hole (13a) is provided.