Irrigation emitter

An emitter comprising:

• a plurality of distinct inlet apertures through each of which liquid separately enters the emitter;
• a manifold flow channel in fluid communication with said plurality of inlet apertures, the manifold flow channel arranged such that all liquid passing through the emitter must pass through the manifold flow channel;
• an elastic diaphragm that seats on the manifold flow channel;
• first and second parts that sandwich the diaphragm between them, wherein the first part is formed having the manifold flow channel;
• and
• an outlet aperture through which liquid that enters the emitter exits the emitter;
• wherein:
• liquid that enters the inlet apertures displaces only a portion of the diaphragm from the manifold flow channel so that the liquid can leave the manifold flow channel and flow through the emitter to reach the outlet aperture;
• the first part is formed having a plurality of protuberances on which the diaphragm rests;
• and
• the protuberances are spaced apart from and surround at least a portion of the manifold flow channel.

An emitter comprising:

• a first part having formed therein a manifold flow channel rimmed with a raised rim and having first and second regions, the manifold flow channel arranged such that all liquid passing through the emitter must pass through the manifold flow channel;
• a second part having formed therein a labyrinth;
• and
• an elastic diaphragm sandwiched between the first and second parts;
• wherein, when liquid enters the manifold flow channel;
• the liquid is substantially prevented from exiting the manifold flow channel in the first region because the second part presses the diaphragm onto the raised rim in the first region, thereby sealing the manifold flow channel in the first region against egress of liquid;
• and
• the liquid pushes the diaphragm off of the raised rim in the second region, thereby allowing the liquid to flow out of the second region between the raised rim and the diaphragm.

An emitter comprising:

• a first part comprising:
• an external surface and an internal surface;
• a plurality of distinct inlet apertures formed in the external surface, each inlet aperture configured to separately permit passage of liquid from the external surface to an interior of the emitter;
• and
• an elongated manifold flow channel formed in the internal surface and in fluid communication with the plurality of inlet apertures, the elongated manifold flow channel being rimmed with a raised rim and having a first region and a second region;
• a second part having formed therein a labyrinth communicating with an outlet;
• and
• a diaphragm sandwiched between the first and second parts,
• wherein:
• when liquid pressure at the external surface of the first part drops below a threshold pressure, the diaphragm is pressed against the raised rim in both the first and second regions to seal the emitter against backflow of liquid into the emitter via the outlet.