Generally, the web seat/stem guided valve design maximizes bearing area because the valve flange is designed to bear on top of the webs in addition to the seating bevel on the inside of the seat, as illustrated in the drawing to the right. While there are several different web seat/stem guided valve designs by different manufacturers, the TRW Mission web seat/stem guided valve design had evolved into the best performing design in the industry.
The performance of this design is due to the maximization of the seat bearing area and the heavy-duty design of the 4-web seat. The success of this design had resulted in the design becoming the de facto standard in the industry, now copied by most all manufacturers.
Previous full open valve and seat designs have suffered from a lack of bearing area. Primarily because the valves of these designs used guide legs that were forged into the main valve body as shown on the valve at the left. Because of forging limitations, these types of guide legs are large and thus restrict flow area. To recover the necessary flow area, the throat in the seat is increased, which reduces bearing area and thus limits the performance of this style of valve & seat. |
KERR
