Flow control arrangement and method of cleaning such an arrangement

A flow control arrangement comprising

• a first valve member being movable along a longitudinal direction into sealing engagement with a first valve seat and being movable along a direction opposite the longitudinal direction from said sealing engagement with the first valve seat,
• a second valve member being movable along the longitudinal direction into sealing engagement with a second valve seat and being movable along the direction opposite the longitudinal direction from said sealing engagement with the second valve seat,
• a first and a second conduit section each being configured to allow a respective flow of a fluid and being arranged beside each other as seen along the longitudinal direction, wherein the first and second conduit sections are interconnected by a mixing opening allowing a flow of fluid between the first and second conduit sections, wherein the first and second valve seats each extends around the mixing opening at two longitudinally separated positions, wherein the mixing opening is selectively closable and openable by a double valve formed by the first and second valve members,
• wherein in a closed state of the double valve, the first and second valve members are sealingly engaging the first and the second valve seat, respectively, with a longitudinal gap being present between the first and second valve members,
• wherein in an open state of the double valve, the first and the second valve members are brought out of engagement of the first and second valve seat, respectively, and into the second conduit section,
• wherein, in a change from the closed state to the open state, the first valve member is configured to be moved a longer distance compared to a movement of the second valve member, such that, in the open state, the first valve member sealingly engages the second valve member,
• wherein the first valve member comprises a first circumferentially extending gasket being configured to sealingly interact with the first valve seat in the closed state, and a second circumferentially extending gasket arranged further in the direction opposite the longitudinal direction than the first circumferentially extending gasket and being configured to sealingly interact with the second valve member in the open state,
• wherein the second valve member is, at an end facing the first valve member, formed with
• a circumferentially extending ring-shaped surface facing with a major component in the longitudinal direction,
• a recess being surrounded by the ring-shaped surface and being configured to receive a portion of the first valve member, and
• a circumferentially extending edge formed in a transition between the ring-shaped surface and the recess,
• wherein the second circumferentially extending gasket of the first valve member is configured to sealingly interact with the circumferentially extending edge of the second valve member when the double valve is in the open state,
• wherein the second valve member comprises a longitudinally extending hollow valve stem and the first valve member comprises a longitudinally extending valve stem extending inside the longitudinally extending hollow valve stem of the second valve member.

A flow control arrangement comprising

• a first valve member being movable along a longitudinal direction into sealing engagement with a first valve seat and being movable along a direction opposite the longitudinal direction from said sealing engagement with the first valve seat,
• a second valve member being movable along the longitudinal direction into sealing engagement with a second valve seat and being movable along the direction opposite the longitudinal direction from said sealing engagement with the second valve seat,
• a first and a second conduit section each being configured to allow a respective flow of a fluid and being arranged beside each other as seen along the longitudinal direction, wherein the first and second conduit sections are interconnected by a mixing opening allowing a flow of fluid between the first and second conduit sections, wherein the first and second valve seats each extends around the mixing opening at two longitudinally separated positions, wherein the mixing opening is selectively closable and openable by a double valve formed by the first and second valve members,
• an actuator comprising a piston cylinder arrangement with an air connection,
• wherein in a closed state of the double valve, the first and second valve members are sealingly engaging the first and the second valve seat, respectively, with a longitudinal gap being present between the first and second valve members,
• wherein in an open state of the double valve, the first and the second valve members are brought out of engagement of the first and second valve seat, respectively, and into the second conduit section,
• wherein, in a change from the closed state to the open state, the first valve member is configured to be moved a longer distance compared to a movement of the second valve member, such that, in the open state, the first valve member sealingly engages the second valve member,
• wherein the first valve member comprises a first circumferentially extending gasket being configured to sealingly interact with the first valve seat in the closed state, and a second circumferentially extending gasket arranged further in the direction opposite the longitudinal direction than the first circumferentially extending gasket and being configured to sealingly interact with the second valve member in the open state,
• wherein the second valve member is, at an end facing the first valve member, formed with
• a circumferentially extending ring-shaped surface facing with a major component in the longitudinal direction,
• a recess being surrounded by the ring-shaped surface and being configured to receive a portion of the first valve member, and
• a circumferentially extending edge formed in a transition between the ring-shaped surface and the recess,
• wherein the second circumferentially extending gasket of the first valve member is configured to sealingly interact with the circumferentially extending edge of the second valve member when the double valve is in the open state,
• wherein the air connection is configured to, in order to set the flow control arrangement in the open state, supply pressurized air to the piston cylinder arrangement such that a piston is moved in the direction opposite the longitudinal direction, the piston being connected to and thereby draw the first valve member in the direction opposite the longitudinal direction to the open state, wherein the second valve member is also drawn in the direction opposite the longitudinal direction to the open state by the first valve member contacting the second valve member in its movement in the direction opposite the longitudinal direction, wherein the second valve member in the open state is urged towards the first valve member by a compressed spring positioned between the piston and the second valve member.