Patent Publication Number: US-2011048554-A1

Title: Sprayer pressure relief valve

Description:
This application claims the benefit of U.S. Application Ser. No. 61/051,919, filed May 9, 2008, the contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     1. Background Art 
     Pressure relief valves are well known for use with sprayers that operate at elevated pressures. Such a valve is required to open when exposed to a pressure in excess of a predetermined minimum. Prior art valves tend to be very prone to packing out when used with materials having a high solids content such as various types of texture material. When this happens, the solids form a blockage in the outlet or other passage of the pressure relief valve. 
     2. Disclosure of the Invention 
     The pressure relief valve of the instant invention allows automatic operation when over pressurization occurs and also allows the user to operate manually when required. Passages within the valve are minimized in length and specialized geometry is used to ensure that operation of valve is not hindered by dried material after initial use. A shield is also incorporated to ensure safe discharge in case of over pressurization. The pressure relief valve may be activated repeatedly. Also the valve allows for manual operation in case the hose is packed out and pressure cannot be relieved in the system at the spray valve. 
     These and other objects and advantages of the invention will appear more fully from the following description made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows a cross-section of the pressure relief valve of the instant invention. 
         FIG. 2  shows a cross-section of the pressure relief valve of the instant invention as incorporated in the outlet of a reciprocating piston pump. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     The pressure relief valve  10  of the instant invention is shown in detail in  FIG. 1  and as attached to the outlet  12  of a reciprocating piston pump  14  in  FIG. 2 . Valve  10  is comprised of a housing  16 , a seat holder  18  threadedly retained therein, a seat  20  located in seat holder  18 , a valve stem  22  having a ball  24  in the end thereof. A spring  26  is located between valve stern  22  and cap  28  to bias valve  10  into the closed position wherein ball  24  seats against seat  20 . Cap  28  is threadedly attached to housing  16  and the end is covered by cap  30 . 
     In the preferred embodiment, valve  10  is threaded directly into the outlet passage  12  of pump  14  minimizing the amount of space that can contain material. Valve outlet passage  32  increases in cross-section as the distance from the ball 24-seat  20  area increases. Put another way, the proximal end  32   a  of passage  32  is smaller in cross-section than the distal end  32   b.  A shield  34  may be used to deflect high pressure material released by the valve  10  so that the energy contained therein may be dissipated. 
     It is contemplated that various changes and modifications may be made to the pressure relief valve without departing from the spirit and scope of the invention as defined by the following claims.