Adjustable spray nozzle

Abstract

The invention is an adjustable spray nozzle useful in airless liquid spraying. The spray nozzle uses interchangeable spray orifice members which discharge against the beveled end of a cylindrical splash pin. The orifice member lines the cylindrical bore which receives the splash pin and the latter is axially adjustable in the spray nozzle body to permit an adjustably variable opening of the orifice, thereby permitting infinite adjustment of the volume of liquid and the area of the fan spray produced by the spray nozzle. The interchangeability of the orifice members provides a wide range of adjustability since interchangeable orifice members of varied orifice diameters can be readily substituted in the spray nozzle.1. Field of InventionThis invention relates to a spray nozzle and, in particular, relates to an adjustable spray nozzle useful in airless spraying of liquids such as paint.2. Brief Statement of the Prior ArtIn airless spraying, liquid is discharged through orifices of minute diameters under very high pressures. The resultant spray has a characteristic fan shape to achieve uniform coating of the liquid, such as paint on a surface. A long felt need in this application is an adjustment capability whereby the volume of liquid discharge and the area of the fan spray can be adjusted at will by the operator. Presently, most applications require replacing the spray nozzle assembly or orifice member with one having a different orifice diameter and this interrupts and delays the spraying operation. Furthermore, only limited adjustment is achieved with interchangeable orifice members since the spray from each separate orifice member cannot be adjusted.Some attempts have been made and in recent years to provide adjustable spray nozzles and these attempts have utilized quite complex mechanisms. One such attempt is disclosed in U.S. Pat. No. 3,414,196 in which several orifice members are permanently secured to a bar which is slideably mounted in the spray nozzle body to permit positioning any of the three orifice members into a spraying position. This attempt has not been successful commercially, partly because of great difficulties in sealing the slide bar sufficiently to prevent leakage under the high pressures encountered in airless spraying. Furthermore, the adjustment capability of this approach is still limited since there was no provision for adjustment of the spray from each individual spray member, but only provision for facilitating the interchange of differently sized orifice members.Other approaches are shown in U.S. Pat. Nos. 3,936,002 and 4,126,272, both issued to John D. Geberth. The first of these patents shows a valve member in the form of a cylindrical rod which is moved along a slot in the cylindrical bore receiving the pin to uncover a variable area of the slot. This approach was acknowledged as unsatisfactory by the inventor in the latter of the two above-identified patents. In the latter patent, the patentee states that the difficulties experienced with the device of his former patent can be cured by positioning the pin at a 45 degree angle to the direction of the liquid discharged from the slot in the cylindrical wall. The resultant spray nozzle, however, still has disadvantages. The spray nozzle provides only a limited range of spray adjustment. The orifice members cannot be interchanged in the nozzle and, the adjustment is thus limited by the size of the orifice (slot) of each nozzle. The user must purchase several nozzle assemblies and replace these assemblies at a significant expense and time deiay, to obtain a wide range of adjustment. A relatively ancient patent, Bowers U.S. Pat. No. Re. 13,366 of 1912, (long before the advent of the liquid airless spraying), discloses the use of a flat slide plate having a beveled edge as a valve member to be moved over a orifice of spray nozzle. Despite its obvious simplicity, this approach has been disregarded in favor of the more complex mechanisms disclosed in the aforementioned recent patents. The approach shown in this ancient patent is not readily adaptable to airless spraying because it does not produce the desirable fan spray pattern necessary for airless spraying of paints.BRIEF STATEMENT OF THE INVENTIONThis invention comprises an adjustably variable high pressure spray nozzle having a body with mounting means to secure it to a spray gun and a fixedly adjustable spray discharge orifice valve member that permits a close control of the volume and the area of the resultant spray. The spray nozzle uses interchangeable orifice members, so orifice members of different diameter orifices can be interchanged in a rapid and facile manner. To this end, the body of the nozzle has a receptacle from the orifice member and locates the orifice member along a cylindrical bore that receives a cylindrical splash pin. The orifice member has a arcuately concave face, conforming to the contour of this cylindrical bore. The orifice spray member is secured in its receptacle by a removable plug. The cylindrical splash pin has a beveled end surface, which is positioned opposite the orifice of the orifice spray member, and is slideably mounted in the spray nozzle body so that it can be moved into a position covering or uncovering a variable area of the orifice whereby the volume and area of the resultant spray can be fixedly adjustable.

Description

Claims

1. A spray assembly comprising:

(a) a body having a through bore and a partial bore intersecting said through bore adjacent one end thereof;

(b) fluid inlet port means and a fluid passageway in said body communicating between said inlet port means and said intersecting bore;

(c) spray gun attachment means operatively secured to said body to permit the discharge of fluid into said inlet port means;

(d) a cylindrical splash pin having a beveled end slideably inserted into said through bore and retaining means associated therewith for fixed adjustability of its position in said through bore, with its beveled end positioned at the intersection of said through bore and partial bore; and

(e) an orifice spray nozzle member having an arcuately concave discharge face with a small diameter orifice received in said partial bore and secured at the intersection of said through bore and intersecting bore by orifice member retaining means also received in said partial bore.

2. The spray assembly of claim 1 wherein said through bore and partial bore are orthogonal.

3. The spray assembly of claim 1 wherein said partial bore is threaded and said orifice member retaining means is a retainer plug threadably engaged in said partial bore.

4. The spray assembly of claim 3 wherein said orifice member retainer plug has a reduced-diameter, apertured, hollow stem to form an annular chamber in said partial bore surrounding said stem and wherein said fluid passageway discharges into said annular chamber.

5. The spray assembly of claim 4 wherein said orifice member has a central passageway communicating with the hollow stem of said retainer plug.

6. The spray assembly of claim 4 including seal means to seal said annular chamber.

7. The spray assembly of claim 4 including first and second O-rings, one each at opposite ends of the reduced-diameter stem portion of said retaining plug.

8. The assembly of claim 1 wherein the beveled end surfaces of said splash pin are formed of a wear-resistant material.

9. The assembly of claim 1 wherein said splash pin has a reduced-diameter end and a cylindrical sleeve having a beveled end and formed of a wear-resistant material is received over and permanently affixed to said reduced-diameter end of said splash pin.

10. The assembly of claim 1 wherein said splash pin has a distal flange and said splash pin retaining means comprises an externally threaded retainer sleeve having an annular inner lip to slideably receive and capture said splash pin.

11. The assembly of claim 10 where said means to fixedly adjust the position of said splash pin in said through bore comprises a set screw threadably received in said retainer sleeve.

12. The assembly of claim 11 including key means in said body and cooperative groove means in said splash pin to orient the beveled end of said pin to the discharge orifice of said spray member.

13. The assembly of claim 1 wherein said spray gun attachment means comprises a retainer cap nut and a distally flanged sleeve captured therein with its opposite end threadably received in said body and in communication with said fluid inlet port means.

14. The assembly of claim 13 including a low-frictional-coefficient seal washer in said retainer cap nut to seal against the end of a spray gun while permitting rotation of said body.

15. In an adjustably variable high pressure spray nozzle having a body with mounting means to secure it to a spray gun and a fixedly adjustable spray discharge orifice valve member permitting a close control of the volume and the area of the resultant spray, the improvement permitting a wide range of adjustability which comprises:

a plurality of orifice spray members, each having a flow-limiting, small-diameter spray orifice, and receptacle means in said body for the removable reception of any one of said plurality of spray members; and

orifice spray member retaining means removably secured in said body independently of said orifice valve member whereby orifice spray members can be interchanged to expand the range of variable adjustability of said spray head without removing said spray nozzle from the spray gun and without moving the position of said valve member.

16. The nozzle of claim 15 wherein said valve member is a cylindrical splash pin having a beveled end slideably inserted into a bore in said body with retaining means also in said bore for fixed adjustability of its position in said bore, with its beveled end positioned opposite the orifice of said spray member.

17. The nozzle of claim 16 wherein said orifice spray members have a concave cylindrical discharge face and said receptacle means is a bore intersecting said through bore and said spray members are secured at the intersection of said through and intersection bores by orifice member retaining means also received in said intersecting bore.