A rain gauge includes a cylindrical rain holder having a float in the rain holder and a rainfall value indicator arranged so that as the float moves vertically in the rain holder a pointer moves circumferentially to indicate the amount of rainfall. A cover for the rain holder includes an opening that is less in area than the area of the surface of water in the rain holder, whereby the water level in the rain holder raises less than but in proportion to the rainfall. The pointer is on the float and the float is mounted to a vertical screw so as to rotate as it floats vertically, whereby the pointer points to lettering on the rain holder wall indicating the amount of rainfall. The pitch per inch of the screw is proportional to the ratio of the area of the surface of water in the rain holder to the area of the opening.

The invention concerns a float-controlled flow-control devie for the outlet from a sewage system, especially a rain basin. The bearings for the pivots (7 & 8) that the float arm (4) and the shutter (2) rotate on are mounted on a displaceable structure (3). This makes it possible to vary the outflow volume to be controlled even when the device is in operation, and hence to control it remotely as well.

The invention concerns a device for the regulation of a constant outflow from a liquid container, in particular from a rain reservoir, with an outflow opening for the liquid, wherein to the outflow opening is assigned a movable throttle element, which in dependence on the liquid level regulates the outflow of the liquid from the container. According to the invention, it is proposed that a component part (2) that is form-changeable in dependence on the fluid pressure control the throttle element, wherein takes place the stopping-down movement of the throttle element against a restoring force (spring 5). A device of this sort makes possible a regulation of a constant outflow from a fluid container, without requiring for this the use of a float.

An outflow regulator for a gravity-fed liquid outlet of a liquid reservoir comprising a restriction plate mountable within the liquid outlet for limiting a flow rate of an effluent. The restriction plate allows a lower passage for the effluent when a first level of liquid is reached within the liquid reservoir, and an upper passage for the effluent when a second level of liquid is reached. The regulator also comprises a flapgate pivotable between a closed position where the flapgate covers the lower passage of the restriction device and an open position away from the restriction plate. When the flapgate is in the closed position, the effluent is free to flow out though the upper passage. A float counterweight switches the flapgate between the opened position and closed position according to the liquid level in the reservoir.

The device for controlling fluid flow from a rain retention chamber or the like includes an inlet communicating with the chamber, an outlet permitting fluid to flow out of the device, and a shutter disposed between the inlet and the outlet, and supported in the device for linear shifting between a raised position and lowered position. A control element is rotatably mounted in a device for rotation about a central axis and includes a curved controller surface which is non-concentric with the central axis of the central element, such that rotation of the control element varies the radial distance between the central axis and the controller surface. A coupler member operably connects the shutter with the controller surface, such that rotation of the control element shifts the shutter between the raised and lowered positions to achieve a predetermined flow rate of fluid from the chamber. The device also includes a sensor adapted to detect fluid level in the chamber, and includes an actuator which shifts linearly as a function of the fluid level in the chamber. A transmission member operably connects the actuator with the control element, such that linear shifting of the actuator in response to fluid level fluctuations in the chamber rotates the control element to selectively shift the shutter in a direction which achieves the predetermined flow rate.