Emitter, and drip irrigation tube

An emitter for quantitatively discharging irrigation liquid in a tube to outside of the tube, the tube being configured for allowing the irrigation liquid to flow therethrough, the emitter being configured to be disposed on the tube, the emitter comprising:

• an intake part for receiving the irrigation liquid in the tube;
• a pressure reduction channel for allowing the irrigation liquid received from the intake part to flow therethrough while reducing a pressure of the irrigation liquid;
• a flow rate controlling part for controlling a flow rate of the irrigation liquid supplied from the pressure reduction channel in accordance with a pressure of the irrigation liquid in the tube or in the intake part;
• and
• a discharge part which is supplied with the irrigation liquid which has a flow rate controlled by the flow rate controlling part and is to be discharged to the outside of the tube;
• wherein the flow rate controlling part includes:
• a valve element for opening and closing a channel of the irrigation liquid,
• a valve seat on which the valve element sits when the valve element closes the channel of the irrigation liquid,
• a film which is disposed above the valve element such that the film is separated from the valve element when the pressure of the irrigation liquid is not exerted on the film, and the film is configured to make contact with the valve element to push the valve element toward the valve seat when bent under the pressure of the irrigation liquid in the tube or in the intake part such that the valve element sits on the valve seat, and
• a groove formed on a surface of the valve seat, and configured to communicate between the channel of the irrigation liquid on an upstream side of the valve seat and the channel of the irrigation liquid on a downstream side of the valve seat when the valve element sits on the valve seat, wherein:
• the film pushes the valve element such that the valve element sits on the valve seat when the pressure of the irrigation liquid in the tube is equal to or higher than a predetermined value.