JPS583669A - Liquid distributor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to liquid dispensing devices, and more particularly to devices for dispensing relatively high viscosity materials such as adhesives, hot melt compositions, sealants, and the like.

There are many application fields for dispensing devices (dispensers).
What is desired or needed is that after the nozzle of the dispensing device is closed, the liquid does not spread, drip, or become stringy from the nozzle. This will stop the liquid from flowing out. For this purpose, there has long been a need for a dispensing device in which the liquid exiting the nozzle splatters when the valve of the nozzle is closed. An example of such an attempt to improve drainage is U.S. Patent Nos. 3 and 9.
No. 23,252.

This patent discloses that draining can be improved by retaining the conical needle valve of the dispensing device centrally within the frusto-conical valve seat of the device. To achieve this purpose, a centering bush is arranged in the device, and the needle valve is
f is designed to pass through.

Another example that recognizes the desirability of minimizing liquid dripping and stringing from nozzle holes is U.S. Pat. No. 3,841;
There is a specification of No. 567. According to the disclosure of this patent, by minimizing the volume of the space between the shutoff valve and the nozzle hole, the sticky liquid does not drip from the nozzle hole after the flow of liquid is cut off. , it is possible to minimize the occurrence of stringing.

The inventor has discovered that by eliminating any void space between the isolation valve and the nozzle hole, better drainage of the liquid exiting the nozzle of the dispensing device can be achieved. One aspect of the present invention is based on this discovery. To this end, the present invention provides a "void-free" distribution device, ie a distribution device with zero void volume between the isolation valve and the nozzle bore. Such a void-free dispensing device comprises a needle valve having a conical tip seatable in a frusto-conical valve seat disposed in the nozzle of the device and terminating in the nozzle bore. use. Immediately above this frusto-conical valve seat is a cylindrical valve seat portion that is engageable with the cylindrical portion of the needle valve, so that the cylindrical portion of the valve is initially Liquid is blocked from flowing through the nozzle before the conical portion seats on the frusto-conical valve seat.

In this way, when the valve is completely closed, there will be no drop of liquid in the nozzle dripping or spitting from the nozzle hole.

The present inventor further provides improved seating for the needle valve with the effect of reducing liquid dripping and spitting from the nozzle by providing a needle valve guide surface in the nozzle adjacent to the nozzle valve seat. We found that it can be configured as follows. To this end, the nozzle of the invention includes a plurality of longitudinally extending valve guide surfaces within the nozzle. The guide surface is spaced along the inner bore of the nozzle and is defined between a plurality of longitudinal liquid passageways extending the length of the nozzle.

A first advantage of the invention is that as soon as the valve of the dispensing device is closed, the liquid flowing out of the nozzle is stopped.

Therefore, no liquid will drip from the dispensing device after closing the valve. When this device is used to dispense highly viscous materials such as adhesives and sealants, the unique nozzle and needle valve configuration eliminates the threads that form between the nozzle hole and the substrate to which the viscous material is applied. The pulling phenomenon can be substantially reduced.

These and other objects will become more apparent from the following description of the invention with reference to the accompanying drawings.

FIGS. 1 and 2 illustrate one embodiment of the present invention in a liquid dispensing gun.

The gun 10 includes a cylindrical body 11, an end cap 12, and a nozzle 13. These end caps 12
, body 11, and nozzle 13 all have longitudinally extending bores. In this inner hole, there is a hole 16 of the nozzle 13.
An axially movable needle valve 14 is provided for controlling the flow of liquid out of the valve.

A valve body 11 has an axial inner hole 2 (including l,
Its large diameter portion 21 is located at the forward end of the valve body. This large diameter portion 21 intersects a lateral passageway 22 through which fluid is supplied to the gun.

Furthermore, a vent hole 23 intersects a small diameter portion 24 of the bore 20. Furthermore, an air intake passage 25 is provided that connects the rear end of the valve body and the air intake port 26 .

A bushing 27 is located within the bore 20 of the body 11 and has a bore 28 extending longitudinally therethrough.
A seal assembly 29,30 is supported therein.

In order to prevent liquid from flowing around the bushing 270, an annular groove is provided on the outer peripheral surface of the bushing, and a zero
Fit the ring seal 31. Furthermore, the O-ring seal 321 is fitted into the annular groove formed on the inner peripheral surface of the valve body 11.

The needle valve 14 is fitted with a stopper piston assembly 35 which controls the movement of the valve. The piston assembly includes a nut 36 threaded into the threaded portion 37 of the needle valve and a piston retainer ring 38 sealingly secured to the circumferential surface of the nut 36.0. This retainer ring carries a pair of piston rings 39, 40, between which an elastic gas stud 41 is sandwiched. The outer edge of this gasket is adapted to contact the inner surface of the cylindrical section 42 formed within the end cap 12 to form an air seal between the lower side of the piston and the surface of the cylindrical section 42. There is.

End cap 12 is bolted to the upper end of valve body 11 by bolts (not shown). in this case,
Preferably, a resilient gasket seal 44 is provided at the interface between the end cap and the body.

In communication with the cylindrical portion 42 formed in the end cap 12,
A stepped axial bore 45 is provided that extends axially within the end cap. The upper small diameter portion 46 of this stepped bore is threaded and accommodates an adjustment stud 47. A lock nut 48 secures the stud 47 in the axial adjustment position.

Between the bottom of the stud 47 and the top of the piston assembly 35 is a compression spring 50. The upper end of the compression spring 50 contacts the bottom surface of the stud 47, and the lower end contacts the top surface of the spring retainer 51. The spring retainer is supported on the top surface of the piston assembly nut 36. The axial position of stud 47 within bore 46 is adjusted to adjust or vary the force that holds the needle valve closed.

The dispensing device described above is known except for the shapes of the needle valve 14 and the nozzle 13, and as such does not constitute a feature of the present invention. Therefore, unless otherwise specified,
A feature of the present invention lies in the configuration of the needle valve 14 and nozzle 13.

Next, referring to FIGS. 2 and 3, the nozzle 13 extends forward from its rear end to a portion where it intersects with a frusto-conical valve seat 61 located at the front end within a cylindrical axial direction. It can be seen that it contains pores. This truncated circular conical valve seat 61
further communicates with a small diameter cylindrical nozzle hole 16,
Liquid exits the nozzle through this hole.

At its forward end, the needle valve 14 is connected to the nozzle 1
a cylindrical portion 65 slidably received within a bore 60 of 3;
has. For this slidable fit, the inner hole 60
should be slightly larger than the cylindrical portion 65 of the nozzle, but the gap between the bore and the needle valve should be within approximately 0.002 inch (0.05 wm), preferably 0.001 inch (0.025 tm). ).

Four longitudinal grooves 63 are arranged on the inner surface of the inner hole 60 at equal intervals. This groove extends the entire length of the bore 60, but extends approximately 1/16 inch (1.5 inch) from the bottom of the bore.
9) Since it ends at the top, a short cylindrical portion in which no groove is formed exists at the bottom of the inner hole 60.

At its forward end, the needle valve 14 is connected to the nozzle 1
3, terminating in a conical valve portion 66 which is engageable with a frustoconical valve seat 61 in 3. .

The conical end of the nozzle forms a bevel angle (B) of approximately 36°, and the valve seat 61 forms a bevel angle (B) of approximately 40°. Therefore, a slight gap is created between the conical portion of the needle valve 65 and the rear end of the valve seat 61.

The nozzle 13 has a cylindrical portion 70 that is tightly fitted into the large diameter portion 21 of the cylindrical bore 20 in the valve body 11 . The forward end of the nozzle terminates in a flange 71.

This flange is a known threaded connector (bolt) 73.
It is bolted to the front end of the valve body 11. In this case, the O-ring seal 74ft distribution device main body 11
It is preferable to fit it into a groove 75 formed in the front end of. This seal 74 prevents liquid leakage between the nozzle 13 and the main body 11.

To prevent movement of bushing 27 within bore 20, a spring 76 is disposed between the rear end of nozzle 13 and the forward end of bushing seal assembly 29. The spring 76 biases the bushing rearwardly and pushes against the shoulder 78 formed in the bore 20.
It serves to hold the flange portion 77 of the bushing in engagement with the bushing.

In operation of the device, pressurized liquid is supplied to the liquid inlet 80 of the device. This inlet communicates with the inner bore 21 of the body 10 via a passage 22, and the liquid supplied to the inlet 80 flows into a liquid reservoir 81 formed within the device. The liquid storage chamber 81 further communicates with a longitudinal passage 63 within the nozzle 13 .

The device is actuated to transfer liquid from the liquid storage chamber 81 to the passageway 6.
3 and the valve seat 61 to the nozzle hole 16, high-pressure air is supplied to the air intake port 26. This high pressure air resists the biasing force of the spring 50 and moves the piston assembly 3
5e, move it upward together with the needle valve 14. The upward movement of the needle valve causes the conical portion 66 of the valve to be pulled away from the valve seat 61. Also, as the cylindrical portion 65 of the needle valve moves rearwardly through the forward-most end of the passageway 63, liquid is transferred from the reservoir chamber 81 to the passageway 63.
The water passes through the valve seat 61 and flows to the nozzle hole 16.

This fluid flow continues as long as air pressure is applied to the air intake 26. Control air valve (not shown)
When the air pressure is released, such as by actuating the spring 50, the spring 50 performs a closing movement of the valve. This closing movement is performed sequentially in two stages.

First, upon closing, the forwardmost end 83 of the cylindrical portion 65 of the needle valve passes through the forwardmost end of the passageway 63, and furthermore, the "X"
It passes through a first sealing area indicated by . When the edge 83 of the cylindrical part passes through the forward-most part of the passage 63, the flow of liquid from the reservoir 81 contained within the device is blocked to the nozzle hole 16. Thereafter, during the continuation of the forward movement of the needle valve, until the second sealing stage (or zone) Y completely closes the nozzle hole 16 and completely stops the outflow of liquid, the needle valve is forced into its conical shape. part 6
6 and the frusto-conical valve seat 61 is pushed forward and discharged from the nozzle hole 16. This second seal area Y
is defined by the contact surface of the forward-most end of the conical portion 66 of the needle valve and the forward-most end of the frusto-conical valve seat 61.

The amount of liquid captured and accumulated in the nozzle between these two areas is very small, and since it is not pressurized, this remaining liquid will not leak from the nozzle hole 16 and drip or spit. This is because there is actually no liquid between the valve seat and the nozzle hole 16.

Such two-stage closure with a needle valve and nozzle is often referred to as a "zero cavity" nozzle.

An important advantage of this invention is that there is no void in the nozzle between the valve seat and the valve hole where the liquid is stored.

Therefore, there is no liquid dripping or spitting from the nozzle hole. This minimizes liquid leakage from the nozzle and completely blocks liquid outflow from the nozzle when the valve is moved periodically (several times per second).

Another advantage of the invention is that a ridge 84 defined within the bore 60 between each liquid passageway 63 over the entire length of the nozzle forms a needle valve guide surface in close proximity to the valve seat of the nozzle. At the point. These guide surfaces keep the needle valve concentric with the valve seat so that valve 5. more completely block liquid outflow from the

Although this invention has been described above with reference to a single embodiment, those skilled in the art will recognize that changes and modifications can be made as appropriate without departing from the spirit of the invention. Accordingly, it is not intended that the invention be limited other than as described in the appended claims.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a distribution device embodying the present invention. 2 is an enlarged longitudinal cross-sectional view of the nozzle and nozzle hole of the dispensing device shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along line 3--3 in FIG. 2. [Explanation of symbols of main parts] 10...Distribution gun 11...Cylindrical valve body 12
... End cap 13 ... Nozzle 14 ... Needle valve 16
... Nozzle hole 28 ... Bush inner hole 35 ...
piston assembly

Claims (1)

[Claims] 1. A nozzle having an axially inner hole; a needle valve having a conical portion at its tip and capable of moving in the axial direction; the nozzle inner hole having a truncated conical portion; and an adjacent cylindrical portion, said conical head portion terminating in the outlet aperture of the nozzle and defining a valve seat within said nozzle; the conical portion is adjacent to a cylindrical portion, the cylindrical portion of the needle valve is engageable with the cylindrical portion of the nozzle bore to close a first section of the valve; The conical portion of the valve is engageable with the frusto-conical valve seat to close a second section of the valve following closure of the first section. Liquid distribution device with valve. 2. The liquid dispensing device according to claim 1, wherein the nozzle has a needle valve guide surface located adjacent to the cylindrical portion of the nozzle bore. 3. The liquid according to claim 2, wherein the nozzle guide surface includes a plurality of longitudinally extending ridges formed inside the nozzle. distribution device. 4. The liquid dispensing device according to claim 2, wherein the needle valve guide surface extends over the entire length of the nozzle in the axial direction. 5. A body having an axial bore; a liquid storage chamber defined at least in part by the bore; a nozzle having a full axial bore; and a nozzle having a conical portion at its tip and extending in the axial direction; a movable needle valve; an inner bore of the nozzle communicates with the inner bore of the body for displacing liquid; the inner bore of the nozzle includes a frusto-conical portion and an adjacent V-cylindrical portion; said conical portion terminating an outlet hole of the nozzle and defining a valve seat within said nozzle; and said conical portion of said needle valve being adjacent to a cylindrical portion. the cylindrical portion of the needle valve is engageable with the cylindrical portion of the nozzle bore to close a first section of the valve, and the conical portion of the needle valve is After closing the first area,
A liquid dispensing device, said liquid dispensing device being engageable with said frustoconical valve seat to close a second section of said valve. 6. A liquid dispensing device according to claim 5, including pneumatic drive means for axially moving said needle valve. 7. A main body having a completely blind inner hole in the axial direction; an inner hole attached to one end of the inner hole and extending in the axial direction, and a socket formed in the inner hole and terminating in an outlet hole disposed at the front end. a nozzle having a truncated conical valve seat; a needle having a Y-conical valve portion engageable with the valve seat and movable in an axial direction in both inner holes of the main body and the nozzle; a valve; a liquid motor means mounted in the inner bore of the body for moving the needle valve into and out of engagement with the valve seat; disposed within the nozzle and concentric with the valve seat; a guide means engageable with a cylindrical portion intermediate the needle valve to guide movement of the needle valve along a longitudinal axis of the valve; supplying liquid to the nozzle in front of the guide means; passage means provided in said nozzle for said liquid dispensing device. 8. The liquid dispensing device according to claim 7, wherein the guide means includes a guide surface that can be engaged with the needle valve over the entire length of the nozzle in the axial direction. 9. The liquid dispensing device of claim 8, wherein the guide surface includes a plurality of longitudinally extending ridges formed in the inner bore of the nozzle. 10. The liquid dispensing device of claim 9, wherein said passage means includes a plurality of longitudinally extending grooves disposed between said ridges.