I. Overview of internal thread internal thread spool valve plunger without maintenance, is run, run, drip, leak killer. The principle is driven rotary piston by a hand wheel through the stem in the hole down the middle frame to complete the opening and closing function reciprocates. Internal thread spool valve in operation between the plunger and the sealing ring with an interference fit, adjusting stud by adjusting the valve cover flange, the seal ring compression lateral force in the valve body and the plunger cylindrical bore surface produced seal. Due to elasticity, abrasion resistance, non-toxic high new sealing material with any changes due to thermal expansion caused by automatic compensation, thus ensuring the valve seal, put an end to the internal and external leakage. At the same time internal thread spool valve open torque, large sealing area, wide media adapt high temperature, sealing reliable, long life, easy maintenance. Widely used in petroleum, chemical, power, pharmaceutical, food and other industries. Second, the internal thread spool main connection, the structure size DN (mm) Size (mm) UJ11-UJ11SM-15,25,40C, P, R 15 20 25 32 40 50 L 90 100 120 140 170 200 H 120 140 165 175 195 213 H1 148 175 205 215 246 268 W 80 100 120 140 160 180 G 1/2 '' 3/4 "1" 11/4 "11/2" 2 "L1 14 16 18 20 22 24 S 32 36 46 556 580 Weight (kg) 1.5 2.5 3.5 5.5 8.5 12