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 Invention This 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 Art In 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. This 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.
Metadata
Assignee
- Graham; Phyllis
Inventor
- Oliver J. Calder