Patent Publication Number: US-2021176928-A1

Title: Emitter and drip irrigation tube

Description:
TECHNICAL FIELD 
     The present invention relates to an emitter, and a drip irrigation tube including the emitter. 
     BACKGROUND ART 
     In the related art, drip irrigation is known as a method of growing plants. The drip irrigation method is a method in which drip irrigation tubes are placed in the soil where plants are planted and irrigation liquid such as water or liquid fertilizer is dripped from the drip irrigation tubes into the soil. In recent years, drip irrigation methods have received particular attention because of their ability to minimize the consumption of liquid for irrigation. 
     A drip irrigation tube has a tube with a plurality of through holes through which the irrigation liquid is discharged, and a plurality of emitters (also referred to as “drippers”) joined to the inner surface of that tube to discharge the irrigation liquid from each through hole (see, for example, PTL 1). 
     PTL 1 discloses an emitter including a body and a flap that is movable about a hinge with respect to the body. In this emitter, the body and the flap are formed integrally with each other using the same material. In addition, the flap includes a film (diaphragm) disposed in a frame. In an operational state with the emitter that has been assembled, a recess of the body is covered with the film of the flap turned about the hinge. The recess is formed in the body with a rim provided in a frame housing as a peripheral portion. When the film of the flap is pressed against the rim, a pressure adjustment chamber is formed. The flow rate of liquid that flows out of the pressure adjustment chamber is adjusted by elastic deflection of the film in accordance with pressure variation. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1 
         WO2017/093882 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     To reduce the manufacturing cost, the emitter disclosed in PTL 1 may be formed using a resin material with a low hardness. In this case, when the liquid pressure is high, the film deformed under the pressure of the liquid may make contact with the bottom surface of the recess to deform the bottom surface of the recess, and consequently the flow rate of the liquid that flows out of the pressure adjustment chamber may not be appropriately controlled. 
     An object of the present invention is to provide an emitter and a drip irrigation tube that can appropriately achieve a flow rate adjustment function even when formed using a resin material with low hardness. 
     Solution to Problem 
     An emitter according to an embodiment of the present invention is configured to be joined to an inner wall surface of a tube for carrying irrigation liquid at a position corresponding to a discharging port configured to communicate between inside and outside of the tube to quantitatively discharge the irrigation liquid inside the tube from the discharging port to the outside of the tube, the emitter including: an emitter body; and a base seat part configured to be housed in the emitter body. The emitter body includes: an intake part configured to take in the irrigation liquid, a pressure reducing channel groove communicated with the intake part and configured to form a pressure reducing channel, the pressure reducing channel being configured to carry the irrigation liquid while depressurizing the irrigation liquid, a housing part communicated with the pressure reducing channel groove and configured to house the base seat part, and a diaphragm part having flexibility and configured to deform toward the base seat part when receiving a pressure of the irrigation liquid in the tube in a state where the base seat part is housed in the housing part. The base seat part includes: a base seat with which the diaphragm part under the pressure of the irrigation liquid in the tube makes contact, a communication hole whose one opening is open at the base seat, the communication hole being configured to discharge, toward the discharging port, the irrigation liquid having entered the housing part from the pressure reducing channel groove, and a deformation suppression part disposed to protrude from a surface on a side opposite to the base seat with which the diaphragm part deformed under the pressure of the irrigation liquid makes contact, the deformation suppression part being configured to suppress deformation of the base seat due to the pressure of the irrigation liquid by making contact with the tube when the diaphragm part under the pressure of the irrigation liquid is in contact with the base seat. 
     A drip irrigation tube according to an embodiment of the present invention includes a tube including a discharging port configured to discharge irrigation liquid; and the emitter joined at a position corresponding to the discharging port in an inner wall surface of the tube. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide an emitter and a drip irrigation tube that can appropriately achieve a flow rate adjustment function even when formed using a resin material with low hardness. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view of a drip irrigation tube according to Embodiment 1 of the present invention; 
         FIGS. 2A to 2D  illustrate a configuration of an emitter according to Embodiment 1 after a base seat part is housed in a housing part; 
         FIGS. 3A and 3B  illustrate a configuration of the emitter according to Embodiment 1 after the base seat part is housed in the housing part; 
         FIGS. 4A to 4D  illustrate a configuration of the emitter according to Embodiment 1 before the base seat part is housed in the housing part; 
         FIGS. 5A to 5D  illustrate a configuration of an emitter according to a modification of Embodiment 1; 
         FIGS. 6A to 6D  illustrate a configuration of an emitter according to a modification of Embodiment 1; 
         FIGS. 7A to 7D  illustrate a configuration of an emitter according to a modification of Embodiment 1; 
         FIGS. 8A to 8C  illustrate a configuration of an emitter according to a modification of Embodiment 1; 
         FIGS. 9A to 9D  illustrate a configuration of an emitter according to Embodiment 2 after a base seat part is housed in a housing part; 
         FIGS. 10A and 10B  illustrate a configuration of the emitter according to Embodiment 2 after the base seat part is housed in the housing part; 
         FIGS. 11A to 11E  illustrate a configuration of the emitter according to Embodiment 2 before the base seat part is housed in the housing part; 
         FIGS. 12A and 12B  illustrate a configuration of the emitter according to Embodiment 2 before the base seat part is housed in the housing part; 
         FIGS. 13A to 13C  illustrate a configuration of an emitter according to Embodiment 3 after a base seat part is housed in a housing part; 
         FIGS. 14A to 14F  illustrate configurations of emitters according to Modifications 1 to 3 of Embodiment 3; 
         FIGS. 15A to 15D  illustrate a configuration of an emitter according to Embodiment 4 after a base seat part is housed in a housing part; 
         FIGS. 16A to 16E  illustrate a configuration of an emitter according to Modification 1 of Embodiment 4; 
         FIGS. 17A to 17E  illustrate a configuration of an emitter according to Modification 2 of Embodiment 4; 
         FIGS. 18A to 18E  illustrate a configuration of an emitter according to Modification 3 of Embodiment 4; 
         FIGS. 19A to 19D  illustrate a configuration of an emitter according to Embodiment 5 before a base seat part is housed in a housing part; and 
         FIGS. 20A and 20B  illustrate a configuration of an emitter according to Embodiment 6 after a base seat part is housed in a housing part. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be elaborated below with reference to the accompanying drawings. 
     Embodiment 1 
     Configurations of Drip Irrigation Tube and Emitter 
       FIG. 1  is a sectional view of drip irrigation tube  100  according to Embodiment 1 of the present invention. 
     As illustrated in  FIG. 1 , drip irrigation tube  100  includes tube  110  and emitter  120 . 
     Tube  110  is a tube for carrying irrigation liquid. Examples of the irrigation liquid include water, liquid fertilizer, agricultural chemicals and mixtures thereof. The flow direction of the irrigation liquid in tube  110  is not limited. In addition, the material of tube  110  is not limited. In the present embodiment, the material of tube  110  is polyethylene. 
     In the tube wall of tube  110 , a plurality of discharging ports  111  for discharging irrigation liquid is formed at a predetermined interval (e.g., from 200 mm to 500 mm) in the axis direction of tube  110 . The diameter of the opening of discharging port  111  is not limited as long as irrigation liquid can be discharged. In the present embodiment, the diameter of the opening of discharging port  111  is 1.5 mm. Each emitter  120  is joined at a position corresponding to discharging port  111  of inner wall surface  112 . The cross-sectional shape and the cross-sectional area perpendicular to the axis direction of tube  110  are not limited as long as emitter  120  can be disposed inside tube  110  without causing liquid leakage. 
     Drip irrigation tube  100  is produced by joining rear surface  125  (see  FIG. 2 ) of emitter  120  to inner wall surface  112 . The method of joining tube  110  and emitter  120  is not limited. For example, tube  110  and emitter  120  are joined by welding of the resin material of tube  110  or emitter  120 , bonding with an adhesive agent, and the like. Discharging port  111  may be formed after or before tube  110  and emitter  120  are joined. 
       FIGS. 2A to 3B  illustrate a configuration of emitter  120  after base seat part  122  is housed in housing part  135 .  FIG. 2A  is a plan view of emitter  120 ,  FIG. 2B  is a bottom view,  FIG. 2C  is a left side view, and  FIG. 2D  is a right side view.  FIG. 3A  is a front view, and  FIG. 3B  is a sectional view taken along line A-A of  FIG. 2A .  FIGS. 4A to 4D  illustrate a configuration of emitter  120  before base seat part  122  is housed in housing part  135 .  FIG. 4A  is a bottom view of emitter  120 ,  FIG. 4B  is a plan view,  FIG. 4C  is a sectional view taken along line A-A of  FIG. 4A , and  FIG. 4D  is a front view. 
     As illustrated in  FIG. 1 , emitter  120  is joined to inner wall surface  112  of tube  110  to cover discharging port  111 . The shape of emitter  120  is not limited as long as it can make intimate contact with inner wall surface  112  and cover discharging port  111 . In the present embodiment, in the cross-section of emitter  120  in the direction perpendicular to the axis direction of tube  110 , the shape of rear surface  125  joined to inner wall surface  112  is a substantially arc shape that protrudes toward inner wall surface  112  to match inner wall surface  112 . In plan view, the shape of emitter  120  is a substantially rectangular shape with chamfered four corners as illustrated in  FIG. 2A . The size of emitter  120  is not limited, and may be appropriately determined based on the desired discharge rate of the irrigation liquid from discharging port  111 . In the present embodiment, emitter  120  has a length of 19 mm in the long side direction, a length of 8 mm in the short side direction, and a height of 2.7 mm. 
     In the present embodiment, emitter  120  is formed of an elastic material. Examples of the material of emitter  120  include resin, elastomer and rubber. Examples of the resin include polyethylene and silicone. The flexibility of emitter  120  can be adjusted by the elastic material used. Examples of the adjustment method of the flexibility of emitter  120  include selection of elastic resins and adjustment of the mixing ratio of an elastic resin with respect to a hard resin material. The index representing the hardness of the material of emitter  120  includes the durometer hardness defined in JIS K6253-3 (2012). The hardness of the material of emitter  120  is about D60 in durometer hardness. Note that the durometer hardness may be type A, type D, and type E depending on the type of durometer used for the measurement. For example, when a type D durometer is used and hardness  60  is indicated, durometer hardness D60 is obtained. Regarding the durometer hardness, when the types have the same numerical value, the type D is the hardest, and the type A and the type E are softer in that order. In the present embodiment, when the material has a durometer hardness D60 or smaller, the effect of suppressing the deformation of base seat  161  is favorably ensured. 
     As illustrated in  FIGS. 1 to 4D , emitter  120  includes emitter body  121  and base seat part  122  housed in emitter body  121 . Base seat part  122  is housed in housing part  135  of emitter body  121  from rear surface  125  side opposite to discharging port  111  before emitter  120  is joined to tube  110 . Emitter body  121  and base seat part  122  may be formed integrally with each other, or may be molded as separate members. In the present embodiment, emitter body  121  and base seat part  122  are molded in a state where they are connected with each other through hinge part  123 . The boundary between the emitter body  121  and hinge part  123  is disconnected to house base seat part  122  in housing part  135 . The method for forming emitter body  121 , base seat part  122 , and hinge part  123  integrally with each other is not limited. In the present embodiment, emitter body  121 , base seat part  122  and hinge part  123  are molded integrally with each other by injection molding. 
     Emitter body  121  includes intake part  131 , first connecting groove  132  serving as first connecting channel  142 , pressure reducing groove (pressure reducing channel groove)  133  serving as pressure reducing channel  143 , second connecting groove  134  serving as second connecting channel  144 , and flow rate adjusting part  136 . When base seat part  122  is housed in housing part  135  of emitter body  121 , flow rate adjusting part  136  and discharging part  137  are formed. Intake part  131  opens at front surface  124  of emitter body  121 . First connecting groove  132 , pressure reducing groove  133 , second connecting groove  134  and housing part  135  are open at rear surface  125  of emitter body  121 . 
     When emitter  120  is joined to tube  110 , first connecting groove  132 , pressure reducing groove  133  and second connecting groove  134  serve as first connecting channel  142 , pressure reducing channel  143  and second connecting channel  144 , respectively. With this configuration, a channel composed of intake part  131 , first connecting channel  142 , pressure reducing channel  143 , second connecting channel  144 , flow rate adjusting part  136  and discharging part  137 , and configured to connect intake part  131  and discharging part  137  is formed. This channel carries irrigation liquid from intake part  131  to discharging part  137 . 
     Intake part  131  is disposed in a half region of front surface  124  of emitter body  121 . The number of intake parts  131  is not limited. In the present embodiment, one intake part  131  is disposed in one half surface in the longitudinal axis direction in emitter  120  ( FIG. 2A ). In front surface  124 , flow rate adjusting part  136  is disposed in the region where intake part  131  is not disposed ( FIG. 1 ). Intake part  131  includes intake side screen part  146  and intake through hole  147 . 
     Intake side screen part  146  prevents entry into intake through hole  147  of floating matters in the irrigation liquid taken into emitter  120 . Intake side screen part  146  is open to interior of tube  110 , and includes intake recess  148  and ridge  149 . 
     Intake recess  148  is a recess formed almost entirely in the region of the half surface where diaphragm part  153  is not disposed in front surface  124  of emitter  120 . The depth of intake recess  148  is not limited, and is appropriately set in accordance with the size of emitter  120 . Ridge  149  is formed on the bottom surface of intake recess  148 . In addition, intake through hole  147  is formed in the bottom surface of intake recess  148 . 
     Ridge  149  is disposed on the bottom surface of intake recess  148 . The arrangement and the number of ridges  149  are not limited as long as entry of floating matters in the irrigation liquid can be prevented while taking in the irrigation liquid from the opening side of intake recess  148 . In the present embodiment, a plurality of ridges  149  is arranged in the longitudinal axial direction of intake recess  148 . In addition, ridge  149  may be formed such that the width decreases from front surface  124  of emitter  120  toward the bottom surface of intake recess  148 , or that the width does not change from front surface  124  of emitter  120  toward the bottom surface of intake recess  148 . 
     Intake through hole  147  is formed in the bottom surface of intake recess  148 . The shape and the number of intake through holes  147  are not limited as long as the irrigation liquid taken into intake recess  148  can be taken into emitter body  121 . In the present embodiment, intake through hole  147  is a single long hole formed along the longitudinal axial direction in the bottom surface of intake recess  148 . Since the long hole is covered with the plurality of ridges  149 , one intake through hole  147  appears to be divided into many through holes as viewed from the front side. 
     Irrigation liquid flowing inside tube  110  is taken into emitter  120  while entry of floating matters into intake through hole  147  is prevented by intake side screen part  146 . 
     First connecting groove  132  (first connecting channel  142 ) connects intake through hole  147  (intake part  131 ) and pressure reducing groove  133 . First connecting groove  132  is formed along the outer edge of rear surface  125  of emitter  120 . One end portion of first connecting groove  132  is connected to pressure reducing groove  133 . When tube  110  and emitter  120  are joined to each other, first connecting groove  132  and inner wall surface  112  of tube  110  form first connecting channel  142 . The irrigation liquid taken from intake part  131  flows toward pressure reducing channel  143  through first connecting channel  142 . 
     Pressure reducing groove  133  (pressure reducing channel  143 ) connects first connecting groove  132  (first connecting channel  142 ) and second connecting channel  144 . Pressure reducing groove  133  (pressure reducing channel  143 ) guides, to flow rate adjusting part  136 , the irrigation liquid taken from intake part  131  while depressurizing the irrigation liquid. Pressure reducing groove  133  is disposed along the longitudinal axial direction at one end portion of rear surface  125  in the minor axis direction. The upstream end of pressure reducing groove  133  is connected to first connecting groove  132 , and the downstream end of pressure reducing groove  133  is connected to second connecting groove  134  communicated with flow rate adjusting part  136 . The shape of pressure reducing groove  133  is not limited as long as the above-described function can be ensured. In the present embodiment, pressure reducing groove  133  has a zigzag shape in plan view. In pressure reducing groove  133 , protrusions  139 , each of which has a substantially triangular prism shape protruding from the inner surface, alternate along the flow direction of the irrigation liquid. Each protrusion  139  is disposed such that its tip end does not cross the central axis of pressure reducing groove  133  in plan view. When tube  110  and emitter  120  are joined to each other, pressure reducing groove  133  and inner wall surface  112  of tube  110  form pressure reducing channel  143 . The irrigation liquid taken from intake part  131  is depressurized by pressure reducing channel  143  and guided to flow rate adjusting part  136 . 
     Second connecting groove  134  (second connecting channel  144 ) connects pressure reducing groove  133  (pressure reducing channel  143 ) and flow rate adjusting part  136 . Second connecting groove  134  is a groove that is formed in a straight line shape along the longitudinal axial direction of emitter  120  on rear surface  125  side of emitter  120 . The upstream end of second connecting groove  134  is connected to pressure reducing groove  133 , and the downstream end of second connecting groove  134  is connected to flow rate adjusting part  136  (housing part  135 ). When tube  110  and emitter  120  are joined to each other, second connecting groove  134  and inner wall surface  112  of tube  110  form second connecting channel  144 . The irrigation liquid depressurized by pressure reducing channel  143  flows to flow rate adjusting part  136  through second connecting channel  144 . 
     Flow rate adjusting part  136  adjusts the flow rate of incoming irrigation liquid. Flow rate adjusting part  136  is disposed in a region where intake part  131  is not provided in emitter  120 . Flow rate adjusting part  136  includes housing part  135 , base seat  161 , communication hole  151 , deformation suppression part  152 , and diaphragm part  153 . In addition, base seat part  122  includes base seat  161 , communication hole  151 , connecting groove  162 , deformation suppression part  152 , and protrusion  163 . 
     Housing part  135  includes first recess  155  having a substantially columnar shape, and second recess  156  disposed next to first recess  155  and having a substantially quadrangular prism shape. In first recess  155 , base seat  161  (see  FIG. 1 ) is disposed to adjust the discharging amount of irrigation liquid coming from second connecting channel  122  and discharged from discharging port  111  of tube  110 . Protrusion  163  next to base seat  161  is fit to second recess  156 . After base seat  161  is disposed to first recess  155  and protrusion  163  is fit to second recess  156 , emitter  120  is joined to inner wall surface  112  of tube  110 . 
     Base seat  161  is a region with which diaphragm part  153  deformed under the pressure of the irrigation liquid makes contact. The shape of base seat  161  is not limited. The shape of base seat  161  may be a curved surface or a flat surface. In the present embodiment, the shape of base seat  161  is a flat surface. Cutout groove  150  is formed in the flat surface part where base seat  161  is disposed. 
     Cutout groove  150  is used for appropriately guiding, to first recess  155 , irrigation liquid from second connecting channel  134 . The shape of cutout groove  150  is not limited as long as the above-mentioned function can be ensured. In the present embodiment, cutout groove  150  is formed in a linear shape. 
     Communication hole  151  is used for discharging, toward discharging port  111 , irrigation liquid entering housing part  135  from pressure reducing channel  143 . In the present embodiment, communication hole  151  is open at a center portion of base seat  161 . The size of the opening of communication hole  151  is not limited and may be appropriately set. 
     Connecting groove  162  is a groove for guiding irrigation liquid to communication hole  151  even in a state where diaphragm part  153  is in contact with base seat  161 . One end portion of connecting groove  162  is communicated with communication hole  151 . The other end portion of connecting groove  162  is disposed outside the outer edge of the contact region of base seat  161  in the state where diaphragm part  153  is in contact with base seat  161 . 
     Deformation suppression part  152  makes contact with tube  110  to suppress the deformation of base seat  161  when diaphragm part  153  is in contact with base seat  161  under the pressure of the irrigation liquid. Deformation suppression part  152  is disposed to protrude from the surface on the side opposite to the surface of base seat  161  with which diaphragm part  153  deformed under the pressure of the irrigation liquid makes contact. Deformation suppression part  152  is disposed at the periphery of the opening of communication hole  151  on discharging port  111  side. The shape of deformation suppression part  152  is not limited as long as the deformation of base seat  161  can be suppressed. In the present embodiment, the shape of deformation suppression part  152  includes deformation suppression part body  171  having a columnar shape, and ejection groove  172  formed in deformation suppression part body  171 . In the present embodiment, in plan view, deformation suppression part body  171  has a shape with opposite two arcs and two parallel straight lines connecting the both ends of the arcs. The height of deformation suppression part body  171  is not limited as long as the deformation of base seat  161  can be suppressed. The height of deformation suppression part body  171  may be set such that it makes contact with the inner wall surface of tube  110  when disposed to tube  110 , or that it does not makes contact with the inner wall surface of tube  110  when disposed to tube  110 . 
     Ejection groove  172  can appropriately guide irrigation liquid to discharging port  137  even in a state where deformation suppression part  152  is in contact with tube  110 . Ejection groove  172  is formed in the bottom surface of deformation suppression part body  171 . One end portion of ejection groove  172  is communicated with communication hole  151 , and the other end portion reaches the side surface of deformation suppression part body  171 . As illustrated in  FIG. 2B , preferably, ejection groove  172  reaches the surface on the side opposite to discharging part  137  in deformation suppression part body  171 . When ejection groove  172  is formed in such a direction, external foreign matters such as sand and tree root that entered tube  110  less likely cause clogging of ejection groove  171 . 
     As illustrated in  FIG. 1 , when emitter  120  is joined to inner wall surface  112  of tube  110 , base seat part  122  disposed in housing part  135  and diaphragm part  153  facing base seat  161  form flow rate adjusting part  136  that adjusts the flow rate of the irrigation liquid discharged from communication hole  151  of emitter  120  (base seat  161 ) in accordance with the pressure of the irrigation liquid in tube  110 . In the present embodiment, diaphragm part  153  has a circular shape in plan view. In the present embodiment, diaphragm part  153  is formed integrally with the other configurations (intake part  131 , first connecting channel  142 , pressure reducing channel  143 , and second connecting channel  144 ) of emitter body  121 . 
     Diaphragm part  153  is formed integrally with the other configuration of emitter body  121 , and thus has flexibility. In the state where emitter  120  is joined to inner wall surface  112  of tube  110 , diaphragm part  153  deforms toward base seat  161  under the pressure of the irrigation liquid in tube  110 . 
     In the present embodiment, as described above, emitter body  121  and base seat part  122  are manufactured in a state where they are connected to each other through hinge part  123 . During manufacture of emitter  120 , hinge part  123  connects emitter body  121  and base seat  161 . The shape and the size of hinge part  123  may be appropriately set as long as the above-described function can be ensured. In the present embodiment, hinge part  123  is connected to side surface  126  contiguous with rear surface  125 . Hinge part  123  may be disposed at the side surface located at either end in the longitudinal axial direction of emitter body  121  (the flow direction of the irrigation liquid), or may be located at side surface  126  at either end in the minor axis direction of emitter body  121 . Preferably, to prevent blockage of the flow of the irrigation liquid, hinge part  123  is connected to side surface  126  on the upstream side or the downstream side in the flow direction of the irrigation liquid. 
     When base seat part  122  is housed in housing part  135 , hinge part  123  may be bent or may be separated away from emitter body  121  and base seat  161 . In the present embodiment, hinge part  123  is cut away from emitter body  121 . Hinge part  123  is housed in groove  164  formed in rear surface  125  of emitter body  121 . In the state where hinge part  123  is housed in groove  164  formed in rear surface  125  of emitter body  121 , rear surface  125  of emitter  120  is appropriately joined to inner wall surface  112  of tube  110 . 
     When base seat part  122  is housed in housing part  135 , the cut hinge part  123  is housed in groove  164 . The shape of groove  164  is not limited as long as hinge part  123  can be housed therein and irrigation liquid is not leaked. In the present embodiment, groove  164  is slightly smaller than hinge part  123 . When emitter  120  is joined to tube  110 , base seat  161  is housed in housing part  135  and hinge part  123  is housed in groove  164 . At this time, hinge part  123  is housed by press-fitting hinge part  123  to groove  164  because groove  164  is slightly smaller than hinge part  123 . 
     Discharging part  137  temporarily stores the irrigation liquid from ejection groove  172 . The irrigation liquid reaching discharging part  137  is discharged to the outside from discharging port  111 . 
     Now an operation of diaphragm part  153  in accordance with the pressure of the irrigation liquid in tube  110  is described. 
     Before irrigation liquid is fed into tube  110 , the pressure of the irrigation liquid is not applied to diaphragm part  153 , and diaphragm part  153  is not deformed (see  FIG. 1 ). 
     When the feeding of irrigation liquid into tube  110  is started, the pressure of the irrigation liquid in tube  110  increases and diaphragm part  153  deforms. When the pressure of the irrigation liquid is relatively low, the deformation of diaphragm part  153  is relatively small, and diaphragm part  153  does not make contact with base seat  161 . In this state, communication hole  151  of base seat  161  is not closed, and therefore the irrigation liquid flowing into the space between diaphragm part  153  and base seat  161  from second connecting channel  144  is discharged to discharging part  137  from communication hole  151 . 
     When the pressure of the irrigation liquid exceeds a set value, the deformation amount of diaphragm part  153  further increases, and diaphragm part  153  makes intimate contact with base seat  161 . It should be noted that even when diaphragm part  153  is in intimate contact with base seat  161 , connecting groove  162  is not closed. Therefore, the irrigation liquid flowing into the space from second connecting channel  144  flows through connecting groove  162  and is then discharged from communication hole  151  to discharging part  137 . Thus, even when diaphragm part  153  is in intimate contact with base seat  161 , irrigation liquid of a certain amount or more is discharged to discharging part  137 . 
     Here, in the case where the hardness of emitter  120  is low as in the present embodiment, the greater the deformation amount of diaphragm part  153 , the greater the pressure of diaphragm part  153  against base seat  161 . In this case, when the pressure is excessively high, base seat  161  may deform toward discharging port  111 . To suppress such deformation of base seat  161 , emitter  120  according to the present embodiment includes deformation suppression part  152 . 
     In the present embodiment, even when the deformation amount of diaphragm part  153  increases, deformation suppression part  152  suppresses the deformation of base seat  161 . More specifically, the pressure of diaphragm part  153  against base seat  161  is canceled by the reactive force that is generated when the bottom surface of deformation suppression part  152  makes contact with the inner wall surface of tube  110 . 
     With this configuration, regardless of the pressure of the irrigation liquid in tube  110 , irrigation liquid of a certain amount or greater can be reliably discharged from communication hole  151 . That is, drip irrigation tube  100  according to the present embodiment can discharge irrigation liquid of a certain amount or greater to the outside of tube  110  regardless of whether the pressure of the irrigation liquid is high or low. 
     Effect 
     As described above, emitter  120  according to the present embodiment includes deformation suppression part  152 , and thus the deformation of base seat  161  due to contact of diaphragm part  153  deformed under the pressure of the irrigation liquid can be suppressed. Thus, the flow rate adjustment function of emitter  120  can be appropriately achieved. 
     Modification 
     Deformation suppression part  152  is not limited as long as the above-described function can be ensured. 
     As illustrated in  FIGS. 5A and 5B , deformation suppression part  252  in emitter  220  may include deformation suppression part body  271  having a circular shape in plan view and ejection groove  272  formed in deformation suppression part body  271 . 
     As illustrated in  FIGS. 5C and 5D , deformation suppression part  352  in emitter  320  may include deformation suppression part body  371  and ejection groove  372 . Deformation suppression part body  371  is a plurality of annular protrusions disposed in a nesting form. Each of the plurality of annular protrusions includes a cutout part. A plurality of the cutout parts functions as ejection groove  372 . 
     As illustrated in  FIGS. 6A and 6B , deformation suppression part  452  in emitter  420  may include deformation suppression part body  471  and ejection groove  472 . Deformation suppression part body  471  is a plurality of protrusions each of which has the bottom surface of a circular sector with a center angle of 90°. The plurality of protrusions are separated away from each other with communication hole  151  at the center. The region between two separate protrusions functions as ejection groove  472 . 
     As illustrated in  FIGS. 6C and 6D , deformation suppression part  552  in emitter  520  may include deformation suppression part body  571  and ejection groove  572 . Deformation suppression part body  571  includes a plurality of protrusions. The plurality of protrusions is disposed in a rectangular grid pattern in the flat surface at which communication hole  151  opens. Each region between the plurality of protrusions functions as ejection groove  572 . 
     As illustrated in  FIGS. 7A and 7B , deformation suppression part  652  in emitter  620  may include deformation suppression part body  671  and ejection groove  672 . Deformation suppression part body  672  includes a plurality of protrusions. The plurality of protrusions has a shape of a column with a square bottom surface. Ejection groove  672  includes a plurality of first grooves each connecting the center portions of adjacent two sides of the square and a second groove connecting one end portion of the groove. 
     As illustrated in  FIGS. 7C and 7D , deformation suppression part  752  in emitter  720  may include deformation suppression part body  771  and ejection groove  772 . Deformation suppression part body  771  includes a plurality of protrusions. In the flat surface at which communication hole  151  opens, the plurality of protrusions is arranged in the longitudinal axial direction so as to extend along the minor axis direction. The region between the plurality of protrusions functions as ejection groove  772 . 
     As illustrated in  FIGS. 8A and 8B , deformation suppression part  852  in emitter  820  may include deformation suppression part body  871  and ejection groove  872 . 
     As illustrated in  FIG. 8C , hinge part  923  in emitter  920  according to the present modification may be disposed at surface  126  located at either end in the minor axis direction of emitter body  121 . 
     Embodiment 2 
     A drip irrigation tube according to Embodiment 2 differs from drip irrigation tube  100  according to Embodiment 1 only in configuration of emitter  1120 . In view of this, the emitter  1120  of the drip irrigation tube according to Embodiment 2 is described below. 
     Configuration of Emitter 
       FIGS. 9A to 10B  illustrate a configuration of emitter  1120  according to Embodiment 2 after base seat part  1122  is housed in housing part  1127 .  FIG. 9A  is a plan view of emitter  1120 ,  FIG. 9B  is a bottom view,  FIG. 9C  is a left side view, and  FIG. 9D  is a right side view.  FIG. 10A  is a front view, and  FIG. 10B  is a sectional view taken along line A-A of  FIG. 9A .  FIGS. 11A to 12B  illustrate a configuration of emitter  1120  according to Embodiment 2 before base seat part  1122  is housed in housing part  1127 .  FIG. 11A  is a bottom view of emitter  1120 ,  FIG. 11B  is a left side view of base seat part  1122 ,  FIG. 11C  is a right side view of base seat part  1122 ,  FIG. 11D  is a left side view of emitter body  1121 , and  FIG. 11E  is a right side view of emitter body  1121 .  FIG. 12A  is a plan view of emitter  1120 , and  FIG. 12B  is a front view of emitter body  1121 . 
     As illustrated in  FIGS. 9A to 12B , emitter  1120  includes emitter body  1121 , base seat part  1122  housed in emitter body  1121 . Before emitter  1120  is joined to tube  110  (see  FIG. 1 ), base seat part  1122  is housed in housing part  1127  of emitter body  1121  from rear surface  1125  side opposite to discharging port  111 . Emitter body  1121  and base seat part  1122  may be formed integrally with each other, or may be formed as separate members. In the present embodiment, emitter body  1121  and base seat part  1122  are formed in a state where they are connected to each other through hinge part  1123 . Then, the boundary between emitter body  1121  and hinge part  1123  is disconnected and base seat part  1122  is housed in housing part  1127 . The method of forming emitter body  1121 , base seat part  1122  and hinge part  1123  integrally with each other is not limited. In the present embodiment, emitter body  1121 , base seat part  1122 , and hinge part  1123  are formed integrally with each other by injection molding. 
     Emitter body  1121  includes intake part  1131 , first connecting groove  1132  serving as first connecting channel  1152 , first pressure reducing groove  1133  serving as first pressure reducing channel  1153 , second connecting groove  1134  serving as second connecting channel  1154 , second pressure reducing groove  1135  serving as second pressure reducing channel  1155 , third connecting groove  1136  serving as third connecting channel  1156 , flow rate adjusting part  1137 , and channel opening-closing part  1138 . When base seat part  1122  is housed in housing part  1127  of emitter body  1121 , flow rate adjusting part  1137 , channel opening-closing part  1138  and discharging part  1139  are formed. Intake part  1131  is open at front surface  1124  of emitter body  1121 . On the other hand, first connecting groove  1132 , first pressure reducing groove  1133 , second connecting groove  1134 , second pressure reducing groove  1135 , third connecting groove  1136  and housing part  1127  are open at rear surface  1125  of emitter body  1121 . At rear surface  1125  of base seat part  1122 , fourth connecting groove  1141  serving as fourth connecting channel  1161  and bypass groove  1142  serving as bypass channel  1162  are open. 
     When emitter  1120  is joined to tube  110 , first connecting groove  1132 , first pressure reducing groove  1133 , second connecting groove  1134 , third connecting groove  1136 , second pressure reducing groove  1135 , fourth connecting groove  1141  and bypass groove  1142  serve as first connecting channel  1152 , first pressure reducing channel  1153 , second connecting channel  1154 , second pressure reducing channel  1155 , third connecting channel  1156 , fourth connecting channel  1161  and bypass channel  1162 , respectively. With this configuration, a first channel composed of intake part  1131 , first connecting channel  1152 , first pressure reducing channel  1153 , second connecting channel  1154 , fourth connecting channel  1161 , flow rate adjusting part  1137  and discharging part  1139 , and configured to connect intake part  1131  and discharging part  1139  is formed. In addition, a second channel composed of intake part  1131 , first connecting channel  1152 , second pressure reducing channel  1155 , third connecting channel  1156 , channel opening-closing part  1138 , bypass channel  1162 , flow rate adjusting part  1137  and discharging part  1139 , and configured to connect intake part  1131  and discharging part  1139  is formed. The first channel and the second channel carry the irrigation liquid from intake part  1131  to discharging part  1139 . 
     Intake part  1131  is disposed in the half region of front surface  1124  of emitter body  1121 . The number of intake parts  1131  is not limited. In the present embodiment, one intake part  1131  is disposed in one half surface in the longitudinal axial direction of emitter  1120  ( FIG. 9A ). Flow rate adjusting part  1137  and channel opening-closing part  1138  are disposed in the region where intake part  1131  is not disposed in front surface  1124  ( FIG. 9A ). Intake part  1131  includes intake side screen part  1171  and intake through hole  1172 . 
     Intake side screen part  1171  prevents entry into intake through hole  1172  of floating matters in the irrigation liquid taken into emitter  1120 . Intake side screen part  1171  opens to the interior of tube  110 , and includes intake recess  1173  and ridge  1174 . 
     Intake recess  1173  is a recess formed almost entirely in the half surface region in front surface  1124  of emitter  1120  where first diaphragm part  1184  and second diaphragm part  1188  are not disposed. The depth of intake recess  1173  is not limited, and is appropriately set in accordance with the size of emitter  1120 . Ridge  1174  is formed on the bottom surface of intake recess  1173 . In addition, intake through hole  1172  is formed in the bottom surface of intake recess  1173 . 
     Ridge  1174  is disposed on the bottom surface of intake recess  1173 . The arrangement and the number of ridge  1174  are not limited as long as irrigation liquid can be taken from the opening side of intake recess  1173  while preventing entry of floating matters in the irrigation liquid. In the present embodiment, a plurality of ridges  1174  is arranged in the longitudinal axial direction of intake recess  1173 . In addition, ridge  1174  may be formed such that the width decreases from the front surface  1124  of emitter  1120  toward the bottom surface of intake recess  1173 , or that the width does not change from the front surface  1124  of emitter  1120  to the bottom surface of intake recess  1173 . 
     Intake through hole  1172  is formed in the bottom surface of intake recess  1173 . The shape and the number of intake through holes  1172  are not limited as long as the irrigation liquid taken into intake recess  1173  can be taken into emitter body  1121 . In the present embodiment, intake through hole  1172  is two long holes formed along the longitudinal axial direction of the bottom surface of intake recess  1173 . Since the long holes are covered with the plurality of ridges  1174 , each of the intake through holes  1172  appear to be divided into many through holes as viewed from the front side. 
     The irrigation liquid flowing inside tube  110  is taken into emitter  1120  while intake side screen part  1171  prevents entry of floating matters into intake through hole  1172 . 
     First connecting groove  1132  (first connecting channel  1152 ) connects intake through hole  1172  (intake part  1131 ) and first pressure reducing groove  1133  and second pressure reducing groove  1135 . First connecting groove  1132  is formed along the outer edge of rear surface  1125  of emitter  1120 . First pressure reducing groove  1133  is connected to one end portion of first connecting groove  1132 , and second pressure reducing groove  1135  is connected to a center portion of first connecting groove  1132 . When tube  110  and emitter  1120  are joined to each other, first connecting groove  1132  and inner wall surface  112  of tube  110  form first connecting channel  1152 . Irrigation liquid taken from intake part  1131  flows through first connecting channel  1152  to first pressure reducing channel  1153  and second pressure reducing channel  1155 . 
     First pressure reducing groove  1133  (first pressure reducing channel  1153 ) connects first connecting groove  1132  (first connecting channel  1152 ) and second connecting channel  1154 . First pressure reducing groove  1133  (first pressure reducing channel  1153 ) depressurizes the irrigation liquid taken from intake part  1131  and guides the irrigation liquid toward flow rate adjusting part  1137 . First pressure reducing groove  1133  is disposed along the longitudinal axial direction in one end portion of rear surface  1125  in the minor axis direction. The upstream end of first pressure reducing groove  1133  is connected to first connecting groove  1132 , and the downstream end is connected to second connecting groove  1134  communicated with flow rate adjusting part  1137 . The shape of first pressure reducing groove  1133  is not limited as long as the above-described function can be ensured. In the present embodiment, first pressure reducing groove  1133  has a zigzag shape in plan view. In first pressure reducing groove  1133 , protrusions  1175 , each of which has a substantially triangular prism shape protruding from the inner surface, alternate along the flow direction of the irrigation liquid. Each protrusion  1175  is disposed such that its tip end does not cross the central axis of first pressure reducing groove  1133  in plan view. When tube  110  and emitter  1120  are joined to each other, first pressure reducing groove  1133  and inner wall surface  112  of tube  110  form first pressure reducing channel  1153 . The irrigation liquid taken from intake part  1131  is depressurized by first pressure reducing channel  1153  and guided to flow rate adjusting part  1137 . 
     Second connecting groove  1134  (second connecting channel  1154 ) connects first pressure reducing groove  1133  (first pressure reducing channel  1153 ) and fourth connecting groove  1141  (fourth connecting channel  1161 ). Second connecting groove  1134  is a groove linearly formed along the longitudinal axial direction of emitter  1120  on rear surface  1125  side of emitter  1120 . The upstream end of second connecting groove  1134  is connected to first pressure reducing groove  1133 , and the downstream end of second connecting groove  1134  is connected to fourth connecting groove  1141  (fourth connecting channel  1161 ). When tube  110  and emitter  1120  are joined to each other, second connecting groove  1134  and inner wall surface  112  of tube  110  form second connecting channel  1154 . The irrigation liquid depressurized by first pressure reducing channel  1153  is guided to flow rate adjusting part  1137  through second connecting channel  1154 . 
     Second pressure reducing groove  1135  (second pressure reducing channel  1155 ) connects first connecting groove  1133  (first connecting channel  1153 ) and third connecting groove  1136  (third connecting channel  1156 ). Second pressure reducing groove  1135  (second pressure reducing channel  1155 ) depressurizes the irrigation liquid taken from intake part  1131  and guides the irrigation liquid toward channel opening-closing part  1138 . Second pressure reducing groove  1135  is disposed along the longitudinal axial direction in a center portion of rear surface  1125  in the minor axis direction. The upstream end of second pressure reducing groove  1135  is connected to first connecting groove  1132 , and the downstream end is connected to third connecting groove  1136  communicated with channel opening-closing part  1138 . Second pressure reducing groove  1135  has the same shape as the above-described first pressure reducing groove  1133 . When tube  110  and emitter  1120  are joined to each other, second pressure reducing groove  1135  and inner wall surface  112  of tube  110  form second pressure reducing channel  1155 . The irrigation liquid taken from intake part  1131  is depressurized by second pressure reducing channel  1155  and guided to channel opening-closing part  1138 . 
     Third connecting groove  1136  (third connecting channel  1156 ) connects second pressure reducing groove  1135  (second pressure reducing channel  1155 ) and channel opening-closing part  1138 . Third connecting groove  1136  is a groove linearly formed along the longitudinal axial direction of base seat part  1122  on rear surface  1125  side of base seat part  1122 . The upstream end of third connecting groove  1136  is connected to second pressure reducing groove  1135 , and the downstream end of third connecting groove  1136  is connected to channel opening-closing part  1138  (housing part  1127 ). When tube  110  and emitter  1120  are joined to each other, third connecting groove  1136  and inner wall surface  112  of tube  110  form third connecting channel  1156 . The irrigation liquid coming from second pressure reducing channel  1155  flows to channel opening-closing part  1138  through third connecting channel  1156 . 
     Fourth connecting groove  1141  (fourth connecting channel  1161 ) connects second connecting groove  1134  (second connecting channel  1154 ) and flow rate adjusting part  1137 . Fourth connecting groove  1141  is a groove linearly formed along the longitudinal axial direction of base seat part  1122  on rear surface  1125  side of base seat part  1122 . The upstream end of fourth connecting groove  1141  is connected to second connecting channel  1154 , and the downstream end of fourth connecting groove  1141  is connected to flow rate adjusting part  1137  (housing part  1127 ). When tube  110  and emitter  1120  are joined to each other, fourth connecting groove  1141  and inner wall surface  112  of tube  110  form fourth connecting channel  1161 . The irrigation liquid coming from second connecting channel  1154  flows to flow rate adjusting part  1137  through fourth connecting channel  1161 . 
     Flow rate adjusting part  1137  adjusts the flow rate of incoming irrigation liquid. Flow rate adjusting part  1137  is disposed in the region where intake part  1131  is not disposed in emitter  1120 . Flow rate adjusting part  1137  includes housing part  1127 , first base seat  1181 , communication hole  1182 , deformation suppression part  1183 , and first diaphragm part  1184 . In addition, base seat part  1122  includes first base seat  1181 , communication hole  1182 , connecting groove  1185 , deformation suppression part  1183 , and fourth connecting groove  1141 . 
     Housing part  1127  includes recess  1186 . In recess  1186 , first base seat  1181  configured to adjust the discharging amount of the irrigation liquid coming from second connecting channel  1154  and discharged from discharging port  111  of tube  110 , and second base seat  1187  configured to open and close the second channel are disposed. After first base seat  1181  and second base seat  1187  are disposed in recess  1186 , emitter  1120  is joined to inner wall surface  112  of tube  110 . 
     First base seat  1181  is a region with which first diaphragm part  1184  deformed under the pressure of the irrigation liquid makes contact. The shape of first base seat  1181  is not limited. The shape of first base seat  1181  may be a curved surface or a flat surface. In the present embodiment, the shape of first base seat  1181  is a flat surface. 
     Communication hole  1182  is used for discharging, toward discharging port  111 , the irrigation liquid having entered housing part  1127 . In the present embodiment, communication hole  1182  is open at a center portion of first base seat  1181 . The size of the opening of communication hole  1182  is also not limited and may be appropriately set. 
     Connecting groove  1185  is a groove for guiding the irrigation liquid to communication hole  1182  even in the state where first diaphragm part  1184  is in contact with first base seat  1181 . One end portion of connecting groove  1185  is communicated with communication hole  1182 . The other end portion of connecting groove  1185  is disposed outside the outer edge of the contact region of first base seat  1181  in the state where first diaphragm part  1184  is in contact with first base seat  1181 . 
     When first diaphragm part  1184  is in contact with first base seat  1181  under the pressure of the irrigation liquid, deformation suppression part  1183  makes contact with tube  110  to suppress the deformation of first base seat  1181 . Deformation suppression part  1183  is disposed to protrude from the surface on the side opposite to the surface of first base seat  1181  with which first diaphragm part  1184  deformed under the pressure of the irrigation liquid makes contact. Deformation suppression part  1183  is disposed at the periphery of the opening of communication hole  1182  on discharging port  111  side. The shape of deformation suppression part  1183  is not limited as long as the deformation of first base seat  1181  can be suppressed. In the present embodiment, the shape of deformation suppression part  1183  is defined by the region around communication hole  1182  and the region on the rear side of second base seat  1187 . The height of deformation suppression part  1183  is not limited as long as the deformation of first base seat  1181  can be suppressed. The height of deformation suppression part  1183  may be set such that it makes contact with the inner wall surface of tube  110  when disposed to tube  110 , or that it does not make contact with the inner wall surface of tube  110  when disposed to tube  110 . 
     When emitter  1120  is joined to inner wall surface  112  of tube  110 , base seat part  1122  disposed in housing part  1127  and first diaphragm part  1184  facing first base seat  1181  form flow rate adjusting part  1137  configured to adjust the flow rate of the irrigation liquid discharged from communication hole  1182  of emitter  1120  (first base seat  1181 ) in accordance with the pressure of the irrigation liquid in tube  110 . In the present embodiment, first diaphragm part  1184  has a circular shape in plan view. In the present embodiment, first diaphragm part  1184  is formed integrally with other configurations of emitter body  1121 . 
     First diaphragm part  1184  is formed integrally with other configurations of emitter body  1121 , and thus has flexibility. In the state where emitter  1120  is joined to inner wall surface  112  of tube  110 , first diaphragm part  1184  is deformed toward first base seat  1181  by the pressure of the irrigation liquid in tube  110 . 
     Channel opening-closing part  1138  closes the second channel in accordance with the pressure in tube  110 , and stops the feeding of the irrigation liquid to flow rate adjusting part  1137  through the second channel. Channel opening-closing part  1138  is disposed in the region where intake part  1131  and flow rate adjusting part  1137  of emitter  1120  are not disposed. Channel opening-closing part  1138  includes housing part  1127 , second base seat  1187 , deformation suppression part  1183 , and second diaphragm part  1188 . 
     Second base seat  1187  is a region with which second diaphragm part  1188  deformed under the pressure of the irrigation liquid makes contact. The shape of second base seat  1187  is not limited. The shape of second base seat  1187  may be a curved surface or a flat surface. In the present embodiment, the shape of second base seat  1187  is a flat surface. Cutout groove  1190  is formed in a part of the flat surface where second base seat  1187  is disposed. 
     Cutout groove  1190  is used for appropriately guiding, to recess  1186 , the irrigation liquid from third connecting channel  1156 . The shape of cutout groove  1190  is not limited as long as the above-mentioned function can be ensured. In the present embodiment, cutout groove  1190  is formed in a linear shape. 
     When emitter  1120  is joined to inner wall surface  112  of tube  110 , base seat part  1122  disposed in housing part  1127  and second diaphragm part  1188  facing second base seat  1187  form channel opening-closing part  1138  configured to open and close the second channel in accordance with the pressure of the irrigation liquid in tube  110 . In the present embodiment, second diaphragm part  1188  has a circular shape in plan view. In the present embodiment, second diaphragm part  1188  is formed integrally with other configurations of emitter body  1121 . In addition, flow rate adjusting part  1137  and channel opening-closing part  1138  are connected through bypass channel  1162 . 
     Second diaphragm part  1188  is formed integrally with other configurations of emitter body  1121 , and thus has flexibility. In the state where emitter  1120  is joined to inner wall surface  112  of tube  110 , second diaphragm part  1188  is deformed toward second base seat  1187  by the pressure of the irrigation liquid in tube  110 . 
     In the present embodiment, emitter body  1121  and base seat part  1122  are manufactured in the state where they are connected to each other with hinge part  1123  therebetween as described above. During manufacture of emitter  1120 , hinge part  1123  connects emitter body  1121  and base seat part  1122 . The shape and the size of hinge part  1123  may be appropriately set as long as the above-described function can be ensured. In the present embodiment, hinge part  1123  is connected to surface  1126  contiguous with rear surface  1125 . Hinge part  1123  may be disposed at a side surface at either end in the longitudinal axial direction (the flow direction of the irrigation liquid) of emitter body  1121 , or at side surface  1126  at either end in the minor axis direction both of emitter body  1121 . Preferably, to prevent blockage of the flow of the irrigation liquid, hinge part  1123  is connected to side surface  1126  on the upstream side or the downstream side in the flow direction of the irrigation liquid. 
     Discharging part  1139  temporarily stores the irrigation liquid from communication hole  1182 . The irrigation liquid reaching discharging part  1139  is discharged to the outside from discharging port  111 . 
     Now an operation of first diaphragm part  1184  and second diaphragm part  1188  in accordance with the pressure of the irrigation liquid in tube  110  is described. 
     Before irrigation liquid is fed into tube  110 , the pressure of the irrigation liquid is not applied to first diaphragm part  1184  and second diaphragm part  1188 , and therefore first diaphragm part  1184  and second diaphragm part  1188  are not deformed. 
     When the feeding of irrigation liquid into tube  110  is started, first diaphragm part  1184  of flow rate adjusting part  1137  deforms toward first base seat  1181 . In addition, second diaphragm part  1188  of channel opening-closing part  1138  deforms toward second base seat  1187 . However, in this state, first diaphragm part  1184  is not in contact with first base seat  1181 , and second diaphragm part  1188  is not in contact with second base seat  1184 , and therefore, the irrigation liquid taken from intake part  1131  is discharged to the outside from discharging port  111  of tube  110  through both the first channel and the second channel. In this manner, at the start of the feeding of irrigation liquid into tube  110 , and in the case where the pressure of the irrigation liquid in tube  110  is significantly low and the like, the irrigation liquid taken from the intake part is discharged through both the first channel and the second channel. 
     When the pressure of the irrigation liquid in tube  110  reaches a predetermined first pressure, second diaphragm part  1188  makes contact with second base seat  1187  to close the second channel. At this time, first diaphragm part  1184  is not in contact with first base seat  1181 . In this manner, when the pressure of the irrigation liquid in tube  110  increases to a value enough to deform second diaphragm part  1188 , second diaphragm part  1188  comes closer to second base seat  1187 , and accordingly the amount of the irrigation liquid discharged through the second channel decreases. Then, when the pressure of the irrigation liquid in tube  110  reaches a predetermined first pressure, the irrigation liquid in the second channel is not discharged from discharging port  111 . As a result, the irrigation liquid taken from intake part  1131  is discharged to the outside from discharging port  111  of tube  110  through only the first channel. 
     When the pressure of the irrigation liquid in tube  110  further increases, first diaphragm part  1184  further deforms toward first base seat  1181 . When the pressure of the irrigation liquid is relatively low, the deformation of first diaphragm part  1184  is relatively small, and first diaphragm part  1184  does not make contact with first base seat  1181 . In this state, communication hole  1182  of first base seat  1181  is not closed, and therefore the irrigation liquid entering the space between first diaphragm part  1184  and first base seat  1181  from fourth connecting channel  1161  is discharged to discharging part  1139  from communication hole  1182 . 
     When the pressure of the irrigation liquid exceeds a set value, the deformation amount of first diaphragm part  1184  further increases, and first diaphragm part  1184  makes intimate contact with first base seat  1181 . It should be noted that connecting groove  1185  is not closed even when first diaphragm part  1184  is in intimate contact with first base seat  1181 . Therefore, the irrigation liquid entering the space from fourth connecting channel  1161  is discharged from communication hole  1182  to discharging part  1139  through connecting groove  1185 . Thus, even when first diaphragm part  1184  is in intimate contact with first base seat  1181 , irrigation liquid of a certain amount or more is discharged to discharging part  1139 . 
     Note that also in the present embodiment, emitter  1120  includes deformation suppression part  1183  to suppress the above-mentioned deformation of first base seat  1181 , and the deformation of first base seat  1181  is suppressed by deformation suppression part  1183  even when the deformation amount of first diaphragm part  1184  is increased. More specifically, the pressure of first diaphragm part  1184  against first base seat  1181  is canceled by the reactive force that is generated when the bottom surface of deformation suppression part  1183  makes contact with the inner wall surface of tube  110 . In addition, emitter  1120  includes deformation suppression part  1183  to suppress the above-mentioned deformation of second base seat  1187 , and the deformation of second base seat  1187  is suppressed by deformation suppression part  1183  even when the deformation amount of second diaphragm part  1188  is increased. More specifically, the pressure of second diaphragm part  1188  against second base seat  1187  is canceled by the reactive force that is generated when the bottom surface of deformation suppression part  1183  makes contact with the inner wall surface of tube  110 . 
     With this configuration, regardless of the pressure of the irrigation liquid in tube  110 , irrigation liquid of a certain amount or greater can be reliably discharged from communication hole  1182 . That is, drip irrigation tube  100  according to the present embodiment can discharge irrigation liquid of a certain amount or greater to the outside of tube  110  regardless of whether the pressure of the irrigation liquid is high or low. 
     Effect 
     As described above, emitter  1120  according to the present embodiment has an effect similar to that of emitter  120  according to Embodiment 1. 
     Embodiment 3 
     A drip irrigation tube according to Embodiment 3 differs from drip irrigation tube  100  according to Embodiment 1 only in configuration of emitter  1220 . In view of this, emitter  1220  of the drip irrigation tube according to Embodiment 3 is described below. 
     Configuration of Emitter 
       FIGS. 13A to 13C  illustrate a configuration of emitter  1220  according to Embodiment 3 after base seat part  122  is housed in housing part  135 .  FIGS. 14A to 14F  illustrate configurations of emitter  1220  according to Modifications 1 to 3 of Embodiment 3 after base seat part  122  is housed in housing part  135 .  FIG. 13A  is a plan view of emitter  1220  according to Embodiment 3,  FIG. 13B  is a bottom view, and  FIG. 13C  is a right side view.  FIG. 14A  is a plan view of emitter  1220  according to Modification 1 of Embodiment 3,  FIG. 14B  is a right side view of emitter  1220  according to Modification 1,  FIG. 14C  is a plan view of emitter  1220  according to Modification 2,  FIG. 14D  is a right side view of emitter  1220  according to Modification 2,  FIG. 14E  is a plan view of emitter  1220  according to Modification 3, and  FIG. 14F  is a right side view of emitter  1220  according to Modification 3. 
     As illustrated in  FIGS. 13A to 13C , emitter  1220  according to Embodiment 3 includes emitter body  1221  and base seat part  122  housed in emitter body  1221 . Emitter body  1221  includes first protrusion part  1231  in addition to intake part  131 , first connecting groove  132 , pressure reducing groove  133 , second connecting groove  134  and flow rate adjusting part  136 . 
     First protrusion part  1231  functions to reduce the contact area between emitter  1220  and a parts-feeder during production of the drip irrigation tube. The drip irrigation tube is produced by continuously joining emitter  1220  formed in advance to the inner surface of the tube while continuously forming the tube, for example. At this time, emitters  1220  formed in advance are stored in the parts-feeder, and continuously sent into the tube from the parts-feeder. However, static electricity may be generated due to friction between the emitter and the inner surface of the parts-feeder and the emitter may be stuck to the inner surface of the parts-feeder, thus reducing the production efficiency. In view of this, first protrusion part  1231  is disposed at front surface  124  in emitter  1220  according to the present embodiment. 
     The shape and the installation of first protrusion part  1231  are not limited as long as the contact area with the inner surface of the parts-feeder can be reduced as described above. In the present embodiment, first protrusion part  1231  is disposed over the entirety of one end portion in the minor axis direction along the longitudinal axis of emitter  1220 . In other words, in plan view of emitter  1220 , first protrusion part  1231  is disposed over the entirety of one long side. The height of first protrusion part  1231  is not limited as long as the contact area between front surface  124  and the inner surface of the parts-feeder can be reduced, and may be appropriately set. 
     The shape of first protrusion part  1231  is not limited to the example illustrated in  FIGS. 13A to 13C . For example, as illustrated in  FIGS. 14A and 14B , first protrusion part  1331  may be disposed in a part of a center portion of one long side of emitter  1320  (emitter body  1321 ). In addition, as illustrated in  FIGS. 14C and 14D , first protrusion part  1431  may be disposed at both end portions in one long side. In addition, as illustrated in  FIGS. 14E and 14F , first protrusion part  1531  may be disposed in both long sides of emitter  1520  (emitter body  1521 ). 
     Effect 
     As described above, emitters  1220 ,  1320 ,  1420  and  150  according to the present embodiment can reduce the contact area with the parts-feeder while achieving the effect of the emitter according to Embodiment 1, and thus can improve the productivity. 
     Embodiment 4 
     A drip irrigation tube according to Embodiment 4 differs from drip irrigation tube  100  according to Embodiment 1 only in configuration of emitter  1620 . In view of this, emitter  1620  of the drip irrigation tube according to Embodiment 4 is described below. 
     Configuration of Emitter 
       FIGS. 15A to 15D  illustrate a configuration of emitter  1620  according to Embodiment 4.  FIGS. 16A to 18E  illustrate configuration of emitters  1620  according to Modifications 1 to 3 of Embodiment 4.  FIG. 15A  is a plan view of emitter  1620  according to Embodiment 4,  FIG. 15B  illustrates another exemplary installation of second protrusion part  1631 ,  FIG. 15C  is a sectional view illustrating a shape of second protrusion part  1631 , and  FIG. 15D  is a sectional view illustrating another shape of second protrusion part  1631 .  FIG. 16A  is a plan view of emitter  1620  according to Modification 1 of Embodiment 4,  FIG. 16B  is a front view,  FIG. 16C  is a bottom view,  FIG. 16D  is a left side view, and  FIG. 16E  is a right side view.  FIG. 17A  is a plan view of emitter  1620  according to Modification 2 of Embodiment 4,  FIG. 17B  is a front view,  FIG. 17C  is a bottom view,  FIG. 17D  is a left side view, and  FIG. 17E  is a right side view.  FIG. 18A  is a plan view of emitter  1620  according to Modification 3 of Embodiment 4,  FIG. 18B  is a front view,  FIG. 18C  is a bottom view,  FIG. 18D  is a left side view, and  FIG. 18E  is a right side view. 
     As illustrated in  FIGS. 15A to 15D , emitter  1620  according to Embodiment 4 includes emitter body  1621  and base seat part  122  housed in emitter body  1621 . Emitter body  1621  includes a plurality of second protrusion parts  1631  in addition to intake part  131 , first connecting groove  132 , pressure reducing groove  133 , second connecting groove  134  and flow rate adjusting part  136 . 
     The plurality of second protrusion parts  1631  reduces the contact area with the guide rail during production of the drip irrigation tube. As described above, the drip irrigation tube is produced by continuously joining emitter  1620  formed in advance to the inner surface of the tube while continuously forming the tube, for example. At this time, emitter  1620  is conveyed to the tube with a rail called guide rail. The cross-sectional shape of the guide rail orthogonal to the sending direction of emitter  1620  is substantially complementary with the cross-sectional shape of emitter  1620 , and is partially communicated with the outside. In this case, when emitter  1620  makes contact with the inner surface of the guide rail, emitter  1620  may be clogged, or emitter  1620  may not perform the feeding at a constant speed. In view of this, in emitter  1620  according to the present embodiment, second protrusion part  1631  is disposed at front surface  124 . 
     The shape and the installation of the plurality of second protrusion parts  1631  are not limited as long as the contact area of the inner surface of the guide rail can be reduced as described above. In the present embodiment, the plurality of second protrusion parts  1631  is disposed at an interval over the entire surface along the longitudinal axis of emitter  1620 . The height of second protrusion part  1631  is not limited as long as the contact area between front surface  124  and the inner surface of the guide rail can be reduced, and may be appropriately set. The cross-sectional shape of second protrusion part  1631  orthogonal to the extending direction is not limited. For example, the cross-sectional shape may be a triangular shape (see  FIG. 15C ) or a semicircular shape (see  FIG. 15D ). 
     The position of the plurality of second protrusion parts  1631  is not limited to the example illustrated in  FIGS. 15A and 15B . For example, as illustrated in  FIGS. 16A to 16E , second protrusion part  1631  may be disposed over the whole circumference of the side surface of emitter  1620 . In addition, as illustrated in  FIGS. 17A to 17E , second protrusion part  1631  may be disposed only in a part of the side surface of emitter  1620 . In addition, as illustrated in  FIGS. 18A to 18E , second protrusion part  1631  may be disposed in rear surface  125  of emitter  1620 . 
     Effect 
     As described above, emitter  1620  according to the present embodiment can reduce the contact area with the guide rail while achieving the effect of the emitter according to Embodiment 1, and thus can improve the productivity. 
     Embodiment 5 
     A drip irrigation tube according to Embodiment 5 differs from drip irrigation tube  100  according to Embodiment 1 only in configuration of emitter  1720 . In view of this, emitter  1720  of the drip irrigation tube according to Embodiment 5 is described below. 
     Configuration of Emitter 
       FIGS. 19A to 19D  illustrate a configuration of emitter  1720  before base seat part  122  is housed in housing part  135 .  FIG. 19A  is a bottom view of emitter  1720 ,  FIG. 19B  is a plan view,  FIG. 19C  is a sectional view taken along line A-A of  FIG. 19A , and  FIG. 19D  is a front view. 
     As illustrated in  FIGS. 19A to 19D , the emitter  1720  according to Embodiment 5 includes emitter body  1721  and base seat part  122  housed in emitter body  1721 . Emitter  1720  includes intake part  131 , first connecting groove  132 , pressure reducing groove  133 , second connecting groove  134 , and flow rate adjusting part  1736 . 
     Flow rate adjusting part  1736  includes housing part  135 , base seat  161 , communication hole  151 , deformation suppression part  152 , and diaphragm part  153 . In addition, base seat part  122  includes base seat  161 , communication hole  151 , communication groove  1762 , deformation suppression part  152 , and protrusion  163 . 
     Communication groove  1762  in the present embodiment is shorter than connecting groove  162  of emitter  120  according to Embodiment 1. With this configuration, in communication groove  1762 , the opening on diaphragm part  153  side is completely closed when diaphragm part  153  makes contact with base seat  161  under the pressure of the irrigation liquid. 
     In the drip irrigation tube including emitter  1720 , when the feeding of irrigation liquid into tube  110  is started, the pressure of the irrigation liquid in tube  110  increases, and diaphragm part  153  deforms. When the pressure of the irrigation liquid is relatively low, the deformation of diaphragm part  153  is relatively small, and diaphragm part  153  does not make contact with base seat  161 . In this state, communication hole  151  of base seat  161  is not closed, and the irrigation liquid entering the space between diaphragm part  153  and base seat  161  from second connecting channel  144  is discharged to discharging part  137  from communication hole  151 . 
     When the pressure of the irrigation liquid exceeds a set value, the deformation amount of diaphragm part  153  further increases, and a center portion of diaphragm part  153  makes intimate contact with base seat  161 . It should be noted that when a center portion of diaphragm part  153  makes intimate contact with base seat  161 , the opening of communication hole  151  on diaphragm part  153  side is closed, but the opening of communication groove  1762  on diaphragm part  153  side is not closed. Therefore, the irrigation liquid entering the space from second connecting channel  144  is discharged from communication hole  151  to discharging part  137  through communication groove  1672 . Thus, a certain amount of irrigation liquid is discharged to discharging part  137  even when a center portion of diaphragm part  153  is in intimate contact with base seat  161 . 
     When the pressure of the irrigation liquid further increases, the deformation amount of diaphragm part  153  further increases, and diaphragm part  153  makes intimate contact with base seat  161  so as to entirely cover the opening of communication groove  1762  on diaphragm part  153  side. In this state, the irrigation liquid entering the space from second connecting channel  144  is not discharged to discharging part  137 . That is, the drip irrigation tube including emitter  1720  stops the discharging of the irrigation liquid from discharging port  111  of the tube when the pressure of the irrigation liquid in tube  110  becomes excessive. 
     Effect 
     As described above, emitter  1720  according to the present embodiment can stop the discharging of the irrigation liquid when the pressure of the irrigation liquid in tube  110  is excessive while achieving the effect of the emitter according to Embodiment 1. 
     Embodiment 6 
     A drip irrigation tube according to Embodiment 6 differs from drip irrigation tube  100  according to Embodiment 1 only in configuration of emitter  1820 . In view of this, emitter  1820  of the drip irrigation tube according to Embodiment 6 is described below. 
       FIGS. 20A and 20B  illustrate a configuration of emitter  1820  according to Embodiment 6.  FIG. 20A  is a plan view of emitter  1820  according to Embodiment 6, and  FIG. 20B  is a partially enlarged sectional view taken along line A-A of  FIG. 20A , illustrating a connecting part of cutout groove  150  of base seat part  122  and second connecting channel  144  of emitter body  121 . 
     As illustrated in  FIGS. 20A and 20B , emitter  1820  according to the present embodiment includes emitter body  121  and base seat part  122 . 
     Emitter body  121  includes intake part  131 , first connecting groove  132  serving as first connecting channel  142 , pressure reducing groove  133  serving as pressure reducing channel  143 , second connecting groove  134  serving as second connecting channel  144 , and housing part  135 . Base seat part  122  includes cutout groove  150  (see  FIG. 4B ), base seat  161 , communication hole  151 , connecting groove  162 , deformation suppression part  152 , and protrusion  163 . When base seat part  122  is housed in housing part  135  of emitter body  121 , flow rate adjusting part  136  and discharging part  137  are formed. In addition, a connecting channel is disposed from emitter body  121  to base seat part  122  so as to connect pressure reducing groove  133  and flow rate adjusting part  136  (the space between diaphragm part  153  and base seat  161 ). This connecting channel is composed of cutout groove  150  of base seat part  122  and second connecting channel  144  of emitter body  121 . 
     When emitter  1820  is joined to tube  110 , first connecting groove  132 , pressure reducing groove  133  and second connecting groove  134  serve as first connecting channel  142 , pressure reducing channel  143  and second connecting channel  144 , respectively. With this configuration, a channel composed of intake part  131 , first connecting channel  142 , pressure reducing channel  143 , the above-mentioned connecting channel (second connecting channel  144  and cutout groove  150 ), flow rate adjusting part  136  and discharging part  137 , and configured to connect intake part  131  and discharging part  137  is formed. This channel carries irrigation liquid from intake part  131  to discharging part  137 . 
     In the above-mentioned connecting channel that connects pressure reducing groove  133  and flow rate adjusting part  136  (the space between diaphragm part  153  and base seat  161 ), second connecting channel  144  is composed of emitter body  121 , whereas cutout groove  150  is composed of base seat part  122 . As described above, emitter  1820  is formed by housing base seat part  122  in housing part  135  of emitter body  121 . As such, a small gap is defined between base seat part  122  and housing part  135 . Consequently, the positions of the opening as the downstream end of second connecting channel  144  of emitter body  121  and the opening as the upstream end of cutout groove  150  of base seat part  122  may be shifted from each other, and the irrigation liquid flowing through connecting part thereof may be unintentionally depressurized. In view of this, in the present embodiment, at the boundary between emitter body  121  and base seat part  122 , the opening as the upstream end of cutout groove  150  of base seat part  122  (the opening of the connecting channel at base seat part  122  on emitter body  121  side) is configured to be larger than the opening as the downstream end of second connecting channel  144  of emitter body  121  (the opening of the connecting channel of emitter body  121  on base seat part  122  side), and thus the cross-sectional area of the channel at the connecting part is prevented from being reduced even when the positions of the downstream end of second connecting channel  144  and the upstream end of cutout groove  150  are shifted from each other. Thus, even when the positions of the downstream end of second connecting channel  144  and the upstream end of cutout groove  150  are shifted from each other, unintentional depressurization of the irrigation liquid flowing through the connecting parts is reduced. 
     Effect 
     As described above, emitter  1820  according to the present embodiment can adjust the flow rate of the irrigation liquid with high accuracy while achieving the effect of the emitter according to Embodiment 1. 
     This application is entitled to and claims the benefit of Japanese Patent Application No. 2018-140276 filed on Jul. 26, 2018 and Japanese Patent Application No. 2018-222273 filed on Nov. 28, 2018, the disclosure each of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, it is possible to provide an emitter that can adjust the flow rate of output liquid at a low manufacturing cost. Therefore, wider use of the emitter in technical fields that require long-term dripping, such as drip irrigation and endurance testing, and further development of the technical fields are expected. 
     REFERENCE SIGNS LIST 
     
         
           100  Drip irrigation tube 
           110  Tube 
           111  Discharging port 
           112  Inner wall surface 
           120 ,  220 ,  320 ,  420 ,  520 ,  620 ,  720 ,  820 ,  920 ,  1120 ,  1220 ,  1320 ,  1420 ,  1520 ,  1620 ,  1720 ,  1820  Emitter 
           121 ,  1121 ,  1221 ,  1321 ,  1421 ,  1521 ,  1621 ,  1721  Emitter body 
           122 ,  1122  Base seat part 
           123 ,  923 ,  1123  Hinge part 
           124 ,  1124  Surface 
           125 ,  1125  Rear surface 
           126 ,  1126  Side surface 
           131 ,  1131  Intake part 
           132 ,  1132  First connecting groove 
           133  Pressure reducing groove 
           134 ,  1134  Second connecting groove 
           135 ,  1127  Housing part 
           136 ,  1137 ,  1736  Flow rate adjusting part 
           137 ,  1139  Discharging part 
           139 ,  1175  Protrusion 
           142 ,  1152  First connecting channel 
           143  Pressure reducing channel 
           144 ,  1154  Second connecting channel 
           146 ,  1171  Intake side screen part 
           147 ,  1172  Intake through hole 
           148 ,  1173  Intake recess 
           149 ,  1174  Ridge 
           150 ,  1190  Cutout groove 
           151 ,  1182  Communication hole 
           152 ,  252 ,  352 ,  452 ,  552 ,  652 ,  752 ,  852 ,  1183  Deformation suppression part 
           153  Diaphragm part 
           155  First recess 
           156  Second recess 
           161  Base seat 
           162 ,  1185  Connecting groove 
           163  Protrusion 
           164  Groove 
           171 ,  271 ,  371 ,  471 ,  571 ,  671 ,  771 ,  871  Deformation suppression part body 
           172 ,  272 ,  372 ,  472 ,  572 ,  672 ,  772 ,  872  Ejection groove 
           1133  First pressure reducing groove 
           1135  Second pressure reducing groove 
           1136  Third connecting groove 
           1138  Channel opening-closing part 
           1141  Fourth connecting groove 
           1142  Bypass groove 
           1153  First pressure reducing channel 
           1155  Second pressure reducing channel 
           1156  Third connecting channel 
           1161  Fourth connecting channel 
           1162  Bypass channel 
           1181  First base seat 
           1184  First diaphragm part 
           1188  Second diaphragm part 
           1186  Recess 
           1187  Second base seat 
           1231 ,  1331 ,  1431 ,  1531  First protrusion part 
           1631  Second protrusion part 
           1762  Communication groove