SHUT-OFF AND REGULATING UNIT Russian patent published in 2002 - IPC

FIELD: hydropneumoatomation; plants required throttling flows at high accuracy and in wide range by flow rate, at gas-distributing stations for example which service gas consumers under conditions of considerable (up to 100-fold) change in gas consumption at retained constant pressure in low-pressure gas line. SUBSTANCE: shut-off and regulating unit has body with two shut-off members which are located coaxially and are opened in succession. Guide cylinder for first shut-off member is secured coaxially relative to body. First shut-off member is movable relative to guide cylinder and is engageable with seat. Second shutoff member in form of diminished duplicate of first shut-off member is connected with servo drive. Guide cylinder of second shut-off member is secured with guide cylinder of first shut-off member on side of flow outlet. Body is located vertically. Inlet of flow of adjustable medium to cavity of body is communicated through side hole and flow outlet-from lower butt of body. Secured at lower butt is guide cylinder for first shut- off member which is perforated by straightway holes. First shut-off member is made in form of hollow sleeve movable from outer side of guide cylinder. On side of outlet of flow sleeve is engageable with seat of guide cylinder. On opposite side circular shoulder of sleeve provided with relief openings is supported by return spring relative to blanked-off upper butt of body. Guide cylinder of second shut-off member is perforated by straightway openings and on side of flow outlet it is secured with guide cylinder of first shut-off member. On opposite side, bottom of sleeve of second shut-off member is supported relative to bottom of sleeve of first shut-off member by return spring and is connected with servo drive by means of rod. Sleeve of first shut-off member is mounted for motion inside intermediate cylinder embracing it. Intermediate cylinder is secured with upper blanked-off butt of body forming dampening chamber together with circular shoulder of sleeve. Dampening chamber is communicated with flow outlet on one side through second shut-off member on other side-with circular cavity by means of longitudinal slots which are located on inner wall of intermediate cylinder over length exceeding amount of working stroke of sleeve of first shut-off member. Circular cavity is formed by sleeve of first shut-off member and cylindrical wall of body. Lower butt of above-mentioned cylinder is located at level not higher than lower edge of side hole of cylinder admitting the flow to cavity of body. Straightway openings in guide cylinder of first shut-off member are made in form, for example, of longitudinal and equidistant oriented slots radially located over circumference; they are located at shift relative to lower edge of sleeve for opening each diametrically opposite pair of above-mentioned straightway openings in raising of sleeve. EFFECT: enhanced reliability; increased service life of shut-off regulating unit; ease in maintenance; simplified construction at retained high accuracy of control of flows in wide range of their rates. 2 cl, 2 dwg