Australian Pipeline Valve - Installation, Operation and Maintenance Manual 3 EXPANDING SEAL PLUG VALVE DOUBLE BLOCK & BLEED API6D - TWIN SERIES MODEL TWIN EXPANDING SEAL PLUG VALVE NON LUBRICATED DOUBLE BLOCK AND BLEED DOUBLE BLOCK AND BLEED SOLUTIONS • Permanent integral thermal relief and bleed function • In-line mainternance in case of seal replacement • Very short installation space required • Double isolation function, according API-6D/ISO14313 • Only 1 actuator required to operate the valve Unlike other valve types, the APV TWIN Twinseal style Dual Expanding Twinseal style plug valve creates an optimum seal without causing any abrasion and wear, providing a ‘zero-leakage’ solution, upstream and downstream ensuring a long life-time of the seals and valve, as well as a low opening and closing torque. This unique design is combined with a bleed function, all in one valve, saving space as well as providing a reliable, safe and economical solution. PRODUCT STRUCTURAL FEATURES Used in various industries such as petroleum, chemical industry, chemical fertiliser, power industry etc. Class 150 - 1500LBS and working temperature of -29~180°C. MAIN STRUCTURAL FEATURES • The Twinseal style double expanding plug valve has a rugged structure, reliable sealing, excellent performance and exact tolerances. • Sealing rings around the valve plug provide the seal. It has a unique design incorporating machined and pressed sealing rings. • Bi-directional, double block and bleed. OPERATION PRINCIPLE When the hand wheel is turned, the plug will rotate toward the closing direction for 90 degree turn closing, the plug will then be firmly seated after moving downward into its closing position. When the hand wheel is turned inversely, first of all the plug will move upward and the valve plug and valve seat will be separated till the valve plug is turned 90 degree driven by the plug and finally the bore of the plug will be in alignment with the channel of valve body. The advantage of this type of valve is during the opening and closing of the valve, the plug and valve seat are separated and there is no friction, thus the sealing face experiences no abrasion in the process, at the same time the soft seal is applied for sealing so that there will be no leakage in the process of closing.