Abstract: A device for indicating changes of a fluid flow, comprises a housing (1) and a support member (7), connected with the housing. A valve member (11) is slidable on the support member (7) and is adapted to increase or decrease the through-flow area of a passage (14) provided in the housing for the fluid flow. A spring (13) supported by said support member (7) is urging the valve member to decrease the through-flow area of the passage. Indicating means (15, 16) is arranged to indicate the position of the valve member (11) in the housing. According to the invention, the support member (7) is adjustable relative to the housing in the moving direction of the valve member (11) for adapting the position of the valve member (7) to various magnitudes of fluid flow through the passage (14).

Abstract: A flexible membrane wall divides a control valve housing into two chambers, one for a control fluid and one for a fluid to be processed, the latter chamber containing a valve seat coacting with a valve body secured to the central part of the membrane wall. This wall comprises two membrane members facing said chambers, respectively, and separated by a plurality of stiff supporting elements which are movable relative to each other. Each supporting element is pivotally connected at one end to the valve housing and at the other end to the valve body, whereby axial loads on the membrane members are transferred through the support elements to the housing and valve body.