Emitter and drip irrigation tube

An emitter that includes an emitter main body including at least a recessed portion and a through hole, and a film having flexibility that is joined to at least one surface of the emitter main body so as to seal an opening of at least a part of the recessed portion and the through hole, the emitter being configured to be joined on an inner wall surface of a tube for carrying irrigation liquid at a position corresponding to a discharging port that communicates between inside and outside of the tube, the emitter being configured to quantitatively discharge the irrigation liquid in the tube from the discharging port to the outside of the tube, the emitter comprising:

• an intake part for intake of the irrigation liquid;
• a discharging part configured to be disposed to face the discharging port, and configured to discharge the irrigation liquid;
• a channel configured to connect the intake part and the discharging part, and configured to distribute the irrigation liquid;
• a flow rate reducing part disposed in the channel, and configured to reduce a flow rate of the irrigation liquid in accordance with a pressure of the irrigation liquid in the tube;
• and
• a pressure reducing channel disposed on an upstream side of the flow rate reducing part in the channel, and configured to guide the irrigation liquid taken from the intake part to the flow rate reducing part while reducing a pressure of the irrigation liquid taken from the intake part,
• wherein the flow rate reducing part includes:
• a recess for reducing the flow rate,
• a diaphragm part having flexibility that is a part of the film, and is disposed to close a communication between inside of the recess and inside of the tube,
• a first through hole that opens at an inner surface of the recess, and is communicated with one of the discharging part and the pressure reducing channel,
• a second through hole that opens at the inner surface of the recess, and is communicated with the other of the discharging part and the pressure reducing channel,
• a valve seat part disposed to surround the first through hole or the second through hole and to face the diaphragm part without making contact with the diaphragm part, wherein when a pressure of the irrigation liquid flowing through the tube is greater than a predetermined value, the diaphragm part is allowed to make intimate contact with the valve seat part, and
• a communication groove formed on a surface of the valve seat where the valve seat part is allowed to make intimate contact with the diaphragm part, the communication groove being configured to communicate between the inside of the recess and the first through hole or the second through hole,
• wherein the diaphragm part includes a thin part that is disposed in a shape surrounding a region of the diaphragm part where the diaphragm part is allowed to make intimate contact with the valve seat part, and
• wherein the thin part is formed such that the thin part is recessed with respect to the inside of the tube, and is protruded with respect to the recess.