Ball valve with angled flow ports for a reciprocating piston pump

Abstract: A reciprocating piston pump is provided with angled flow ports to provide enhanced flow and reduced wear characteristics.

Description: BACKGROUND OF THE INVENTION Reciprocating piston pumps have been well known for many years for paint and other viscous materials. While current designs are generally satisfactory for their intended use, users are always desirous of increased packing life so as to prevent interruption of jobs and productivity. US Patent No. 2,181,748 discloses a reciprocating piston pump in which flow ports are provided in a cylindrical rod (12, 17). The axial height of the ports, increases as one proceeds radially outwards. SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a piston port design reduces turbulence, Eddy currents, and loading in the piston area of the pump. It is further an object of this invention to provide increased overall pump efficiency and performance and to eliminate the need for a piston ball stop as the invention creates its own from the rod material. It is further an object of this invention to provide a sight window for ball wear inspection and thus eliminate the need to remove the piston head and damage the packing stack. According to the present invention, there is provided a reciprocating piston pump comprising a cylindrical rod, the rod comprising flow ports therein located between the ends of the rod, the flow ports being generally tapered to increase in diameter in a radially outward direction. Depending on the pump sizing, the countersink hole will be in an optimum flow state which thereby reduces eddy currents and fluid traps by being machined to an angle within a range of 20-80 degrees. This angle also reduces potential wear patterns in the cylinder wall which can serve to reduce pump life. The countersinks allow for a sight window that not only reduces restriction and blockage but allows visual inspection to review ball wear without removing the piston head. This countersink further provides radial and angular flows which serve to reduce side load to a minimum during the down stroke. A flat from the flat bottom drilling provides a precise ball stop limiting ball travel tolerance to a desired distance. The angle must also be related to a dimension "A" as shown in the accompanying drawings and which is determined by the relationship between dimensions X, Y, Z and the 20-80 degree angle. With the two holes meeting at an angle, the pin for a ball stop is able to be removed and replaced with material from the rod thus reducing parts and assemblies. In addition it provides precise ball travel dimension when combined with a one piece fixed head for the piston. The ball head force pressure is in a direct line of the ball to enhance speed and direct line for seating. A key feature in making this design work is the internal ball guides machined into the piston to allow full ball guide alignment and full side exposure without allowing the ball to block the exit ports or escape through the ports. 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. A BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view detailing the instant invention. Figure 2 is a cross-sectional view of the pump incorporating the instant invention. Figure 3 is an exploded view of the pump incorporating the instant invention. DESCRIPTION OF THE PREFERRED EMBODIMENT In a reciprocating piston pump generally designated 10, a rod 12 is provided with a countersunk flow port 14. Depending on the pump sizing, the countersink hole 14 will be in an optimum flow state which thereby reduces eddy currents and fluid traps by being machined to an angle within a range of 20-80 degrees (from the horizontal - total included angles will be from about 40 to 160 degrees). The preferred embodiment utilizes an included angle of about 40 degrees. This angle also reduces potential wear patterns in the cylinder wall 16 which can serve to reduce pump life. The countersinks allow for a sight window that not only reduces restriction and blockage but allows visual inspection to review ball 18 wear without removing the piston head. This countersink further provides radial and angular flows which serve to reduce side load to a minimum during the down stroke. A flat from the flat bottom drilling provides a precise ball stop 20 limiting ball travel tolerance to a desired distance. The angle must also be related to a dimension "A" as shown in the accompanying drawings and which is determined by the relationship between dimensions X, Y, Z and the 20-80 degree angle. With the two holes meeting at an angle, the pin for a ball stop is able to be removed and replaced with material from the rod thus reducing parts and assemblies in addition it provides precise ball travel dimension when combined with a one piece fixed head for the piston. The ball head force pressure is in a direct line of the ball to enhance speed and direct line for seating. A key feature in making this design work is the internal ball guides machined into the piston to allow full ball guide alignment and full side exposure without allowing the ball to block the exit ports or escape through the ports. It is contemplated that various changes and modifications may be made to the port design without departing from the scope of the invention as defined by the following claims.

Claims: A reciprocating piston pump (10) comprising a cylindrical rod (12), the rod (12) comprising flow ports (14) therein located between the ends of the rod (12), the flow ports (14) being generally tapered to increase in diameter in a radially outward direction. A reciprocating piston pump (10) according to claim 1, wherein said ports (14) have an included angle of between about 40 and 160 degrees. A reciprocating piston pump (10) according to claim 2, wherein said ports (14) have an included angle of about 40 degrees. A reciprocating piston pump (10) according to claim 1 further comprising a ball stop (20) formed of material integral with said rod (12).

Inventors: THOMPSON DAVID J, THOMPSON, DAVID J.
Applicants: GRACO INC, GRACO INC.
Application year: 1998
Main classification: F04B53
IPC codes: F04B53, F04B1, B05C11