Abstract: A valve is installed into an underground conduit to control drainage of water through that conduit. The drainage control valve includes a perforated plate across the conduit. The latter plate is formed with a peripheral groove rectangular in cross section and a hollow tube made of flexible material is inserted into this groove to seal the joint between the plate and the inner surface of the conduit. A flap also made of flexible material is applied against the upstream surface of the plate and is formed with a peripheral edge taper whereby pressure applied on the flap by water upstream of the drainage valve forces the edge taper against the upstream plate surface to form a sealed joint between these flap and plate. The upper portion of the flap is attached to the upper portion of the plate through screw and nut assemblies. These assemblies traverse rigid washers inserted in respective holes made in the flap.

Abstract: The disclosure herein describes a control device for use with an underground drainage and irrigation network formed of a main conduit line and of adjacently disposed water permeable secondary conduit lines. At least one head control stand is used defining a water-collecting chamber with a pair of float members therein. These floats are operatively connected to respective drainage and irrigation control valves. The chamber communicates with an underground duct having a free, perforated end positioned between a pair of secondary lines to collect underground water received in the chamber to influence the floats. The valves are operated by the floats to maintain an underground water table between the two adjacent secondary lines at a level adequate for optimal plant growth.

Abstract: The disclosure herein describes a control device for use with an underground drainage network of main collectors and adjacently disposed water-collecting pipes. A head control stand is used defining a water-collecting chamber with a float member therein. The latter is operatively connected to a valve disposed in an associated main collector and is opened as a result of the float member being influenced by the measurement of the water table depth between two adjacently disposed water-collecting pipes of the network. The valve remains opened as long as the level of underground water exceeds a value corresponding to optimal plant growth.