Flow emitter units moulds for use in the manufacture thereof

An emitter unit having wall means for defining an elongated flowduct having a flowduct inlet and a flowduct outlet and a unit inlet and a unit outlet respectively coupled to the flowduct inlet and the flowduct outlet;

• said flowduct comprising a central elongated control duct of substantially rectangular cross-sectional shape having a width a and two sets of successive like flow pockets located respectively on either side of the control duct and opening into the control duct;
• each flow pocket of said sets being defined between a pair of adjacent side walls of a pair of successive baffles of a corresponding set of baffles, between first and second opposite flowduct walls and a flowduct side wall;
• the baffle side walls terminating in a baffle edge of width c and of height b, the baffles of one set being respectively directed substantially towards the mid-points of the inter-baffle regions of the opposite set;
• the baffle edges of each set of baffles being substantially aligned and defining one pair of opposite longitudinal sides of the control duct, the other pair of longitudinal sides of said control duct being defined by first and second opposite control duct walls, the aligned edges of one set of baffles being substantially parallel to the aligned edges of the opposite set of baffles;
• the dimensions of a and c relative to d where d is the minimum throughflow spacing in said flowduct between successive oppositely directed baffles being such that c lies substantially in the range 0-0.25 d and a lies substantially in the range 0.2 d-0.4 d.