Abstract: A cylindrical, or part cylindrical, diaphragm for a drip emitter is disclosed, the diaphragm having a depressed labyrinthine path in the outer face thereof. The path is constituted by a groove, there being one or more holes in the diaphragm which place one end of the groove in communication with the interior of the diaphragm. The diaphragm has a thinner area which forms a distortable membrane. The other end of the groove communicates with the space which lies radially outwardly of the membrane. The diaphragm is placed in a cylindrical holder which has a hole in the walling thereof. Said membrane extends over the hole in the holder.

Abstract: A pressure compensating, water flow control device in which the incoming water is split between first and second flow paths. The first flow path is in the form of a closed loop and the second flow path includes a vortex chamber. The outlet from the device is co-axial with said vortex chamber. Both ends of the closed loop communicate with an inlet zone. The vortex chamber is, in one form, connected to said inlet zone by a passage and, in another form, said chamber and said inlet zone are contiguous.