The 6-inch ANSI Class 600 Fabri-Valve Knife Gate Valve (METC SOA Test Valve No. A-11) accumulated 313 cycles in the Valve Static Test Unit (VSTU) and 684 cycles in the Valve Dynamic Test Unit (VDTU). Following modifications, METC SOA Test Valve No. A-11R accumulated 1699 cycles in the VSTU and 1392 cycles in the VDTU. The test valve satisfactorily completed all static test runs conducted at 70/sup 0/F (ambient), 300/sup 0/F, and 600/sup 0/F. During the initial dynamic tests using limestone as the test medium, internal leakage rates exceeded the maximum allowable rate. Excessive leakage occurred due to solids accumulation in the seat area, preventing proper closure. Following the addition of the seat purge system, this problem was eliminated. However, subsequent testing in the VDTU revealed excessive leakage rates once again. The problem appeared to have been caused by improper alignment of the gate and seat. With appropriate modifications, the Fabri-Valve Knife Gate Valve could have potential for use in solids-discharge lockhopper service.