Grate and water recovery system

A grate for use as a self-cleaning filter, comprising

• a grate assembly adaptable for mounting in an installed position along a diagonal plane to a horizontal axis with said grate formed with a leading edge opposed to a trailing edge, such that in the installed position the trailing edge is vertically lower than the leading edge, such grate assembly formed with a plurality of spaced upraised rib sections that each extend in the direction from the said leading edge to the said trailing edge, with at least
• one flange section located between a pair of said rib sections, the upper surface of which flange section extends in the said diagonal plane, and with at least
• one opening located between a pair of said rib sections and extending in the direction from the trailing edge to the leading edge, such that
• the flow of a liquid freely falling upon an upper section of the grate will be distributed between some flow of liquid on said flange or flanges flowing towards the trailing edge and some flow of liquid through said opening, and such that where debris in the liquid that falls on the said flange or flanges, and where said debris is of a larger size than the opening will accomodate, the said debris will be splashed or pushed by the flow of water on the flanges towards the trailing edge of the grate while most or all of the said water will fall through the opening before reaching the trailing edge,
• together with first receiver means located to receive liquid that is filtered through the opening of said grate, where said first receiver means is located below the grate opening, in which
• the said first receiver means is a storage tank for recovery and reuse of drain water, together with
• a receptacle for containment of chemicals useful in treatment of drain water, with said receptacle linked to the storage tank by a valve, together with means responsive to flow of water into said storage tank which means is linked to said valve so as to open said valve when water is flowing into said storage tank, and to close said valve upon cessation of such water flow, in which
• the said means to control said valve comprises
• pivotal means of mounting of said grate in a first generally diagonal plane,
• spring means to bias the trailing edge of said grate in an upwards direction to said first diagonal plane,
• said pivotal means located so that weight of water on the flanges of said grate biases the trailing edge of the grate in the downwards direction from said first diagonal plane, to a second diagonal plane of said grate,
• linkage means for said grate to said valve such that when said grate is pivoted by the flow of water to the second diagonal plane, the said valve is opened, with said linkage means closing said valve when the grate is in the first diagonal plane.