Top-entry ball valve assembly having camming surfaces

#1. Field of the Invention

#The present invention relates to ball valves and, more particularly, to a wearless top-entry ball valve assembly with a pair of camming plates coupled to the top and bottom of the ball valve member to retract the valve seats as the ball valve is rotated between open and closed positions; and, the assembly also allows for automatic flushing, i.e., flushing without removing the bonnet.

#2. General Background

#For a further understanding of the nature and objects of the present invention, reference should be had to the following description taken in conjunction with the accompanying drawings in which like parts are given like reference numerals and, wherein:

#FIG. 1A illustrates an exploded view of the top-entry ball valve assembly of the present invention;

#FIG. 1B illustrates an exploded view of the ball valve member with its stem and the camming plates;

#Referring now to the drawings and in particular FIGS. 1A, 1B, and 2-9, the top-entry ball valve assembly of the present invention is generally referenced by the numeral 100. The top-entry ball valve assembly 100 of the present invention is generally comprised of a body 1 allowing flow therethrough and which removably houses a ball valve member 3 and stem 3a. The ball valve member 3 via stem 3a fit within a pair of spring-biased seats 7 and is adapted to rotate to selectively block flow through the bore 25 in ball valve member 3. The upper and lower surfaces or shoulders of ball valve member 3 have integral thereto upper and lower cam plates 46 and 48, respectively (alternatively, the plates 46, 48 can be welded to member 3). Therefore, the upper and lower cam plates rotate in unison about the longitudinal axis of stem 3a. With reference to FIGS. 3, 5 and 7, since the upper and lower cam plates 46 and 48 are essentially identical, only one such cam plate will be described in detail. Upper cam plate 46 is a quasi-square shaped plate. The use of the term “quasi-square” will be made apparent by the description provided herein.

#The quasi-square shaped plate includes two pairs of opposing parallel sides A1, A2 and B1, B2 which are essentially straight and are designed to abut in direct surface-to-surface contact with a forward annular flange 7a of the spring-biased valve seats 7 when the ball valve member 3 is in its open position (FIG. 2) or, alternately, closed position. However, the four corners of the quasi-square shaped plate are truncated and they do not have the same radius with respect to the center axis AX. The truncated corners provide paired opposing, camming corner-surfaces CS1 and CS2. While the corners are truncated, the truncation creates slightly curved camming corner-surfaces CS1 and CS2 having first and second arc-lengths AL1 and AL2 (FIGS. 5 and 7) so that as the ball valve member 3 is rotated about stem 3a, the camming operations are generally smooth and retraction of the spring-biased seats 7 is gradual.

#With reference to the paired camming corner-surfaces CS1, radius R1 is the distance measured from the center C1 of the arc-length AL1, as best seen in FIG. 7, of each camming corner-surface CS1 of the pair to the center axis AX. Moreover, the paired camming corner-surface CS2 (the “repair cams”) of the pair have a radius R2 measured from the center axis AX to the center C2 of the arc-length AL2 of such camming corner-surface CS2.