Pressure regulator for maintaining a stable flow level of a fluid

A flow regulator for maintaining a stable rate of flow of a fluid in a flow channel (2), comprising a flow-actuated element (4) which is movable under the influence of a pressure drop in the fluid flow, and a throttle valve (10) for regulating the fluid flow under the influence of said element (4), characterized in that flow-actuated element (4) constitutes a control element for a servo means (11) comprising a pilot valve (17) for controlling the movement of a drive means (12) coupled to a valve body (19) in the throttle valve (10), and which, by means of the servo means (11), is arranged to be moved in a smooth manner independently of sudden changes in the fluid flow, said control element (4) being arranged to be moved in the flow direction only when the rate of flow exceeds a preselected level, said control element (4) including a piston forming a partition between a first chamber (5) connected to the flow channel (2) upstream of a pressure-drop orifice (3) in the channel, and a second chamber (6) connected to the channel (2) at the downstream side of the orifice (3), and that the drive means (12) is arranged in the second chamber (6) and comprises a piston housing (3) and a drive piston (14) which together defines a third chamber (15) at the side of the piston (14) facing away from the throttle valve (10), the third chamber (15) by means of the pilot valve (17) being arranged to be filled with fluid from the second chamber (6) or emptied of fluid in dependence on the movement of the control element (4), the drive piston (14) at the side facing the throttle valve (10) being influenced by the pressure in the second chamber (6), and on the opposite side being influenced by the force from a prestressed drive spring (16) and by the pressure from the fluid supplied to the third chamber (15), so that the drive piston (14) is moved when the resulting force from the drive spring (16) and the fluid pressure in the third chamber (15) exceeds or becomes less than the force influence from the pressure in the second chamber (6).

A flow regulator for maintaining a smooth and stable rate of flow of a liquid in a flow channel under a relatively high pressure, e.g. 100-300 bars, comprising

• a flow actuated element (4) which is moveable under the influence of a pressure drop in the liquid flow, and which is influenced by a preset force acting oppositely to the flow direction, so that the element is only moved when the rate of flow exceeds a preselected level,
• a pressure-balanced throttle valve (10) having a valve body (19) for regulating the liquid flow under the influence of the flow-actuated element (4), and
• a servo means (11) which is connected between the flow-actuated element (4) and the throttle valve (19), said element constituting a control element for the servo means,
• the servo means (11) comprising a pressure-balanced pilot valve (17) arranged to cooperate with a drive means (13, 14, 18) in such a manner that the drive means after a time delay follows the movement of the control element without exertion of any counter-acting force on the control element,
• the drive means being rigidly connected to the valve body (19) of the throttle valve (10) to slave-control the valve body so that the movement thereof after said time delay corresponds to the movement of the flow-actuated element.